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HomeMy WebLinkAboutMiscTECHNICAL MEMORANDUM Project: Subject: Date: Authors: Renton Heritage Apartments Transportation Impact Analysis June 17, 2014 Jennifer Barnes, P.E. Tod McBryan, P.E. DRAFT : l i! j i~ This report presents the transportation impact analysis for the proposed mixed use development at 207 - 219 Main Avenue S in Renton. It includes a description of existing and proposed conditions in the site vicinity, projected trip generation and distribution, operational analysis where site-generated traffic would access the street system, and an assessment of the project's impacts to transit service and non- motorized facilities. The analysis presented in this report follows traffic impact analysis guidelines that have been established by the City of Renton (City).' 1. Project Description The site consists of four parcels, one of which was occupied by a service station and three vacant lots. It is bounded by Main Avenue S on the east, an alley on the west, S 2"d Street on the north, and private parcels on the south. The site vicinity is shown on Figure I. The project would construct a six-story building with IO I apartments and up to 5,000 square feet (st) of ground-level neighborhood retail space. The project would provide on-site parking for 10 I vehicles, which would be accessed from the alley. The project would also dedicate right-ot:way and make improvements such that the alley would be 16- feet wide along the project frontage (approximately 250 feet) south from S 2"d Street. The proposed site plan is shown on Figure 2. It should be noted that the alley currently extends about 400 feet south from S 2"d Street and ends. However, City staff has indicated that in conjunction with redevelopment of this block, the City would acquire an easement and/or right-of-way to connect the alley from its current southern terminus east to S Main Avenue. The City would also make the requisite improvements to the alley south of the project site (approximately 270 feet) to S Main Avenue.2 Therefore, this report assumes that with the proposed project, the alley would provide access at S 2"d Street and S Main Avenue. City of Renton, Policy Guidelines for Traffic Impact Analysis for New Development, Rev. March 12, 2008. City of Renton, Rocale Timmons, June 16, 2014. heffron -1 -June 17, 2014 11¥1,4--l•i•IMMIIM,MeMMIIM "' w '< r: w z a: ::, <D 900 Renton Heritage Apartments Project "' w '< "' ::, ,,; ~ ~ ji;: z w '< S 2nd ST "' w '< "' ~ ~ ~ S 3rd ST z w '< Jones Park "' w '< z < ::, SITE ~ " S 4th ST z w '< >; ~ w Q_ N 2nd ST Figure 1 SITE VICINITY UJ '< a: '3 UJ u z w '< z w D a: <t C) Liberty Park "' UJ '< z ~ UJ a: z w '< "' 0 D <t w ::, heffron • N Not:o Scale z w '< >-a: 0 ,_ u ft Cedar River Park trans ortat1on inc 06 17.2014 = Source: Stricker Cato Mur h Architects, June 2014 Renton Heritage Apartments Project 0 Figure 2 SITE PLAN -0 io, l ~ i . ... '·.i \ ~ ~ jr:11 11 IT ~ 101 ¢ heffron • N trans ortat1on inc 0617.2014 Renton Heritage Apartments Transportation Impact Analysis 2. Roadway Network 2.1. Existing Network DRAFT The City of Renton designates streets as principal arterials, minor arterials, collectors, and local access streets depending upon the street's function in the roadway network.1 The key roadways in the vicinity of the project site are described below. Main Avenue S is a Principal Arterial that extends from S Grady Way to Bronson Way S. It continues as a local access street for about two blocks to the north of Bronson Way S. North of Houser Way S, it is one-way in the southbound direction. In the vicinity of the project site, it has two southbound general purpose lanes and on-street parallel parking lanes (with 2-hour restrictions) on both sides. The roadway has a posted speed limit of 25 miles per hour (mph) and curbs, gutters, and sidewalks on both sides. S 2°• Street is a Principal Arterial that extends from Main Avenue S to Rainier Avenue S, and is one-way in the westbound direction. For one block to the east of Main Avenue S, it is a local access street. In the vicinity of the project site it has four westbound general purpose lanes; the southernmost lane transitions into a left-turn lane at Williams Avenue S, and into a parking lane farther west. The roadway has a posted speed limit of 25 mph and curbs, gutters, and sidewalks on both sides. S 3'• Street is a Principal Arterial that extends from Rainier Avenue S to Main Avenue S, and is one-way in the eastbound direction. In the vicinity of the project site, it has two eastbound general purpose lanes and parallel on-street parking (with 2-hour restrictions) on both sides, and curb bulbs at each intersection. The roadway has a posted speed limit of 25 mph and curbs, gutters, and sidewalks on both sides. Wells Avenue Sis a Minor Arterial that extends from S Grady Way to N 4'" Street, and is one-way in the northbound direction. Between N 4 '" Street and N 6'" Street it continues as a local access street. In the vicinity of the project site, it has two northbound general purpose lanes and parallel on-street parking ( with 2-hour restrictions) on both sides, and curb bulbs at each intersection. The roadway has a posted speed limit of 25 mph and curbs, gutters, and sidewalks on both sides. Regional access to the site vicinity is provided via Interstate-405 (l-405), State Route (SR) 169 (Maple Valley Highway), and SR 167. SR 169 and 1-405 are accessed at Bronson Way N/Sunset Boulevard N interchange, about Y, mile northeast of the project site. SR 167 and 1-405 are accessed at the Rainier Avenue S interchange, about 1 Y, miles southwest of the project site. 2.2. Planned Transportation Projects in Site Vicinity The City ofRenton's 2014-2019 Six-Year Transportation improvement Program' was reviewed to determine if any proposed projects would affect study-area roadways. No projects are identified in the vicinity of the project site. However, as described previously, City staff has indicated that, in conjunction with redevelopment of the project site, the City would acquire an easement and/or right-of- way lo connect the alley from its current southern terminus east to S Main Avenue. The City would also make the improvements to the alley south of the project site (approximately 270 feet) to S Main Avenue. Therefore, completion of the alley connection is assumed in the future "with project" analysis presented in this report. 4 City of Renton, Arterial Streets, Revised on June 24, 2013, Resolution 4189. City of Renton, 2013. heffron -4 - ii•IMMlll•i,FNIEM June 17, 2014 Renton Heritage Apartments Transportation Impact Analysis 3. Trip Generation DRAFT Vehicle trip generation for the proposed Renton Heritage Apartments project was determined using rates and equations provided in the Institute of Transportation Engineers (!TE) Trip Generation' which compiles trip generation counts throughout the country for a variety of land-use types. Procedures established by !TE in the Trip Generation Handbook6 were applied to determine whether the average rates or equations were appropriate for each proposed land use. Trip generation rates and equations used to derive the trip generation for the proposed project are summarized in Table 1. These were applied to the proposed apartment and retail land uses to estimate the total vehicle trips that these uses would generate. Since there is currently no active land use on the site, no trips were estimated for the existing land use nor applied as credit against the proposed development. Table 1. !TE Vehicle Trip Generation Rates and Equations Applied to Project Trips Rates and Equations Land Use (ITE Land Use Code) Dailv AM Peak Hour PM Peak Hour Apartment (LU 220)" T O 6.06(X) + 123.56 T O 049(X) + 3.73 T O 0.55(X) + 17.65 (50% in, 50% out) (20% in, 80% out) (65% in, 35% out) Shopping Center (LU 820) 42.70 trips/ 1,000 sf 0.96 trips/ 1.000 sf 3.71 trips/ 1,000 sf (50% in, 50% out) (62% in, 38% out) ( 48% in, 52% out) Source: Institute of Transportation Engineers (/TE} Trip General/On. 9" Edition. 2072. a. T O average vehicle /rip ends; X O number of dwelling units. The vehicle trips projected to be generated by the proposed project arc summarized in Table 2. As shown, the project is anticipated to generate 950 vehicle trips per day (475 in, 475 out), with 58 occurring during the AM peak hour, and 92 occurring during the PM peak hour. Table 2. Estimated Vehicle Trips Generated by the Proposed Project AM Peak Hour Trips PM Peak Hour Trips Prooosed Land Use Size Daily Trips In Out Total In Out Total Proposed Apartments 101 units 740 11 42 53 47 26 73 Retail 5,000 sf 210 3 2 5 g 10 19 Total Project Trins 950 14 44 58 56 36 92 Source.· Heffron Transporta/lon. Inc., June 2074. 6 Institute of Transportation Engineers. Trip Generation, 9'" Edition, 2012. Institute of Transportation Engineers, Trip Generation Handbook, 2"' Edition. 2004. heffron -5 -June 17, 2014 IIMMii--Mii•IMW¥ill•i1MMBM Renton Heritage Aparlments Transportation Impact Analysis 4. Trip Distribution and Assignment DRAFT Trip distribution patterns were developed for the project-generated trips based on existing traffic patterns in the site area. Table 3 summarizes the overall origins and destinations that were assumed for this analysis and presented to City staff during the traffic analysis scoping process. 7 The resulting total project trip distribution patterns for the daily, AM, and PM peak hours are shown on Figure 3. The site trips were assigned to the roadway network based on the trip distribution patterns shown. The resulting trip assignment is also shown on Figure 3. As discussed previously, the trip distribution reflects the assumption that, with redevelopment of the site, the alley would be extended to provide access at S 2"' Street and S Main Avenue. Table 3. Project Trip Distribution Percentages To/From % Trios North via 1-405 35% South/west via 1-405 25% South via SR 167 20% East via SR 169 10% North via Park Avenue N 5% West via S 2"' StreeVS 3'' Street 3% West via SW Gradv Wav 2% Total Trins 100% Source: Heffron Transportation, 2014. 5. Traffic Operational Impacts 5.1. Traffic Volumes Existing AM and PM peak hour tratlic volumes at intersections in the vicinity of the project site were obtained from new turning movement counts performed on Wednesday, May 14, 2014. The existing intersection turning movement volumes are shown on Figure 4. City ofRenton's Policy Guidelines for Traffic Impact Analysis For New Development' indicate that operational analysis is required for intersections that would experience a 5% increase in peak hour traffic volumes as a result of the proposed development. Table 4 summarizes the increase in intersection volumes expected to result from the proposed project. The table reflects existing AM and PM peak hour conditions as well as the expected project-generated trips described in the previous section. As shown, the project is not expected to increase intersection volumes by 5% or more at any intersection during either peak hour. The largest increase is estimated at 4.3%; therefore, operational analysis of the study area intersections is not required. ' Traffic scoping meeting with Jan Illian, May I, 2014, City of Renton, 2008. heffron -6- IIMliMei•IMMIM•MiWMIMM June 17, 2014 ,r-56(14) "' w " " w z 0: C, "' ® LEGEND 1 9 (10) ADT 90 900 (0)2-+ "' w " "' "' ,,; ~ ~ ~ +-XX PM Peak Hour Volume (XX) AM Peak Hour Volume Renton Heritage Apartments Project z w " "' w " "' ~ ~ UJ s S 3rd ST ADT 19 z w " "' ~ ~ w s Jones Park t z w " ~ w Q_ N 2nd ST (I) 3 t z "' w " ~ w u z w " z w 0 t 0: <( Cl 2 (2) Liberty Park (34)27~ z w " s 0 0 <( w "' .. N Not to Scale z w " >-0: 0 >-u ;:< <59 Cedar River Park Outbound Route and Trip Percentage f\.'0::::11.-,llo..lnbound Route ~ __ j ~ and Trip Percentage !ADT xxxl Average Daily Trips (ADT) Figure 3 PROJECT TRIP DISTRIBUTION DAILY, AM AND PM PEAK HOURS heffron trans ortat1on inc 06.17.2014 t.._ 27 (14) .____ 451 (603) (4) (536) 30 8l3 l (231 I 740 ---+ (46) 199 ,. LEGEND 1 t 171 127 (118) (91) ~ 894 (1219) S 3rd ST ._ XX PM Peak Hour Volume (XX) AM Peak Hour Volume Renton Heritage Apartments Project z z w w ::;, ::;, U) :,:; ~ ~ ~ w w ,: 0.. N 2nd ST z w ::;, "' "' i't Jones Parle U) w ::;, S4th ST Figure 4 EXISTING (2014) VOLUMES AM AND PM PEAK HOURS (527) 406 ,.J (525) 803 i .____a2111) .------67 (14) (15) (3) (16) 26 19 89 l ,.J i (0) 3 ----------3' (3) (16) 15 51 l (1) 3---+ (0) 4 y • N No:to Scae z w ::;, >-"' 0 >-0 ii t.._ 14 (0) .____ 39 (5) .-----3 (0) 1 t ~ 307 41 101 (763) 171 (76) Cedar River Parle (814) 443----------3' (704) 1251---+ (21) 43,. t ~ 48 34 (50) (35) heffron trans ortat1on inc 06.17.2014 Renton Heritage Apartments Transportation Impact Analysis DRAFT Table 4. Increase in Peak Hour Intersection Volumes Resulting from Project Intersection/ Peak Period Total Enterinq Volume Proiect T rins Added Percent Increase AM Peak S 2°d Street/ Wells Avenue S 826 10 1.2% S 2" Street/ Main Avenue S 1.137 14 1.2% S 2°d Street/ Mill Avenue S 886 7 0.8% Houser Way S / Mill Avenue S 1.643 27 1.6% S 3'd Street/ Main Avenue S 2,036 41 2.0% S 3" Street/ Wells Avenue S 486 a 0 0.0% PM Peak S zed Street/ Wells Avenue S 776 9 12% S 2'' Street/ Main Avenue S 1,358 56 4.1% S 200 Street/ Mill Avenue S 649 28 4.3% Houser Way S / Mill Avenue S 1,887 44 2.3% S 3" Street/ Main Avenue S 2,736 55 2.0% S 3'" Street/ Wells Avenue S 1,237' 2 0.2% Source: Heffron Transportation. Inc., June 207 4. a. Although turning movement counts were not conducted at this intersection, total volume through the intersection was derived based on the counts at the ad;acent 1i1tersect1ons to the north and east To evaluate potential site access impacts, operational analysis was conducted for the alley intersections with S 2"' Street and S Main Avenue. Analysis was conducted for future 2016 conditions, which is the year the project is proposed to be completed and occupied. To determine an appropriate rate for background traffic growth, the 2014 traffic counts at the study area intersections were compared to 2008 counts provided by the City. Overall, the count comparison indicated that traffic volumes have decreased in the study area since 2008; this is consistent with trends that have been observed throughout the Puget Sound region. However, the counts did indicate that traffic growth has occurred on S 3'' Street over that period, at a rate of about 1.2% per year. Therefore, to estimate background traffic volumes for 2016 conditions, a compound annual growth rate of 1.2% per year was applied to existing volumes. The resulting 2016 "without project" volumes at the alley intersections are shown on Figure 5. To estimate 2016 traffic volumes with the proposed project, the project trips (presented previously on Figure 3) were added to the "without project" volumes. Forecast 2016 "with-project" volumes at the alley intersections are shown on Figure 6. heffron -9 -June 17, 2014 IIMM,4-Wii•IIMIM•MiWWW z ,.__ 485 (605) .----15 (5) 1 5 (25) S 2nd ST "' w "' "' "' w w "' "' t: "' z w :,e « z ~ "' a: ~ 0 => ~ ~ "' 3: S 3rd ST 900 LEGEND ._ XX PM Peak Hour Volume (XX) AM Peak Hour Volume Renton Heritage Apartments Project "' w "' "' ~ ~ w ,: z z w w "' "' "' '.':; ~ ~ ~ w w ,: Q. N 2nd ST z w "' "' ~ Jones Parl< "' w "' z « :,e ~ ~ :,; SITE ~ ID a/ S 4th ST Figure 5 FUTURE (2016) WITHOUT PROJECT TRAFFIC VOLUMES AM AND PM PEAK HOURS z w "' z w D a: « "' Liberty Parl< (0)(555) O 925 J + (0) 0-----. z w "' ,: 0 0 « w :,e heffron • N Not. to Sca'e z w "' >-a: 0 0 ~ Cedar River Parl< trans ortat1on inc 06.17.2014 z w '< +-485 (605) ,.--71 (19) 1 14 (35) S 2nd ST 900 u, w u, u, '< w w '< '< " u, z w :,; <t z :,; '-' "' ~ 0 => ~ ~ "' ea: S 3rd ST 900 LEGEND +-XX PM Peak Hour Volume (XX) AM Peak Hour Volume Renton Heritage Apartments Project "' w '< u, ~ ~ w " z z w w '< '< u, ':, ~ ~ ~ w w " "- N 2nd ST z w '< " "' it Jones Park u, w '< z <( :,; SITE ~ w '< S 4th ST Figure 6 FUTURE (2016) WITH PROJECT TRAFFIC VOLUMES AM AND PM PEAK HOURS z w '< z w 0 "' <t '-' Liberty Park (555) (0) 925 j i (34) 27 ----,. z w '< " 0 0 <t w :a heffron • N Not to Scale z w '< >-"' 0 ,- 0 ;£ Cedar River Park rans ortat1on inc 06.17.2014 Renton Heritage Apartments Transportation Impact Analysis 5.2. Traffic Operations Analysis DRAFT To evaluate potential site access impacts, level of service (LOS) analyses were performed for the alley intersections with S 2"d Street and S Main Avenue for the AM and PM peak hours. Level of service is a qualitative measure used to characterize traffic operating conditions. Six letter designations, "A" through "F," are used to define level of service. LOS A is the best and represents good traffic operations with little or no delay to motorists. LOS F is the worst and indicates poor traffic operations with long delays. Level of service for intersections is based on average delay per vehicle in seconds. Levels of service for the study area intersections were analyzed using methodologies presented in the Highway Capacity Manual.9 Delay is calculated using complex equations that consider a number of variables. For example, at unsignalized intersections, delay is determined for vehicles that must stop or yield for oncoming traffic. That delay is related to the availability of gaps in the main street's traffic flow and the ability of a driver to enter or pass through those gaps. All level of service calculations were performed with Trafficware's Synchro 8.0 analysis software. Because the HCM 2010 module is not set up to evaluate a stop-controlled intersection at a street with more than two through-lanes, levels of service were reported using the HCM 2000 unsignalized module of the Synchro software. Table 5 summarizes the existing (2014) and forecast 2016 levels of service, with and without the proposed project, at the two alley intersections. As shown, with the added alley connection and additional project-generated trips, all movements at both intersections are expected to operate at LOS B or better. Therefore, no adverse operational impacts related to site access are anticipated. Table 5. Level of Service Summary -Existing (2014) and Forecast 2016 Peak Hours Existing (2014) 2016 Wrthout Project 2016 With Project Unsiqnalized Intersections LOS 1 Delay 2 LOS Delay LOS Delay AM Peak Hour S z,, Street I Alley Northbound from Alley A 9.9 A 9.9 B 10.1 Westbound on S 2" Street A 0.1 A 0.1 A 0.2 Main Avenue S I Alley Eastbound from Alley N/A 3 NIA B 11.9 PM Peak Hour S 2" Street I Alley Northbound from Alley A 9.9 A 9.9 B 10.5 Westbound on S z,, Street A 0.2 A 0.2 A 0.6 S Main Avenue I Alley Eastbound from Alley NIA NIA B 14.1 Source: Heffron Transportalion. June 2014. 7. LOS" Level of service. 2. Delay= Average seconds of delay per vehicle. 3. Alley in/ersec/ion does no/ curren/ly exisl; proposed by Cily in coryune/ion wilh projec/ 9 Transportation Research Board. 2010. Highway Capacity Manual. Special Report 209. Washington, DC. heffron -12 -June 17, 2014 4--IEM•IMfflli•ieFMIM Renton Heritage Apartments Transportation Impact Analysis 6. Traffic Safety DRAFT Collision data for intersections and roadway segments surrounding the project site were obtained from the Washington State Department of Transportation (WSDOT). These data, reflecting the period between January I, 2011 and May 31, 2014 (about 3.4 years), were examined to determine if there are any unusual traffic safety conditions that could impact or be impacted by the proposed project. The collision data are summarized in Table 6. As shown, the highest number of collisions was recorded at the S 2"d Street/Main Avenue S/Bronson Way S intersection. One collision at this intersection in 2011, involving a right turning pick-up or panel truck hitting a pedestrian, resulted in a fatality. Table 6. Collision Summary (January 1, 2011 through May 31, 2014) Head-Rear-Side-Right Left Right Ped/ Total for Average/ Intersection On End Swipe Tum Tum Angle Cycle Other 3.4 Years Year S 2"' St I Wells Ave S 0 0 1 1 3 3 0 0 8 2.4 S 2"' St I Main Ave S 0 2 1 2 3 10 1 a 0 19 5.6 S 3'' St/ Wells Ave S 0 0 0 0 5 7 1 0 13 3.8 S 3,d St/ Main Ave S 0 0 0 1 0 4 0 0 5 1.5 Head-Rear-Side-Right Left Right Ped/ Total for Average/ Roadway Segment On End Swipe Tum Tum Angle Cycle Otherb 3.4 Years Year S 2'' St -between Wells 0 0 0 0 0 0 0 0 0 0.0 and Main Aves S S 3,, St -between Wells 0 1 0 0 0 0 0 2 3 0.9 and Main Aves S Main Ave S -between S 0 0 0 0 3 0 0 1 4 1.2 2'" St and S 3" St Source· Washington State Department of Transportation. Collision data for the period 07/07/2077 through 05/37/2074. a. Collision wl/h pedestrian resulted in a fatality. b. "Other"" col/is1ons involved parked vehicles or vehicles exiting a parking space. 7. Transit Service Impacts Transit service in the site vicinity is provided by King County Metro. A bus stop serving Route 280 is located directly in front of the project site on Main Avenue S just south of S 2"d Street. Less than Y, mile southwest of the site, the Renton Transit Center is served by several bus routes that provide daily service to and from Seattle, Bellevue, Renton Highlands, and other areas of Renton; additional commuter service is provided to and from Kent, Enumclaw, and other regional destinations. Although the trip generation estimates conservatively assume that all trips generated by the project would occur by vehicle, some transit trips could also be generated. There is ample transit service in the site vicinity to accommodate additional transit riders, and no adverse impacts to transit are anticipated. heffron -13 -June 17, 2014 =lii•MMW¥1ii•MeWMIMM Renton Heritage Apartments Transportation Impact Analysis 8. Non-Motorized Facility Impacts DRAFT The project would provide frontage improvements along its S 2"' Street and Main Avenue S frontages including replacing the sidewalks and providing new landscaping to meet City of Renton standards. The proposed project is expected to increase pedestrian activity in the area (persons walking, bicycling and taking transit to and from the site). The area is served by a complete sidewalk network, with marked crosswalks provided at signalized intersections. No adverse non-motorized impacts are anticipated. 9. Transportation Impact Fee The 2013-14 City of Renton Fee Schedule identifies transportation impact fee rates of $953.25 per apartment unit, and $3.22 per square foot of retail (shopping center). Based on these rates, the transportation impact fee for the proposed project is estimated to be $112,378.25 [(IOI apartments x $953.25/unit) + (5,000 sf x $3.22 sf)]. The project should be given credit against these fees for removal of the previous use. The actual traffic impact fee and credit amount will be determined at the time of building permit issuance based on the final project program. 10. Summary of Findings The project would construct a six-story building with IO I apartments, up to 5,000 sf of retail space on the ground level, and parking for 101 vehicles, which would be accessed at the alley. The project would also dedicate right-of-way and make improvements such that the alley would be 16-feet wide along the project frontage (approximately 250 feet south from S 2"' Street). The City of Renton has indicated that in conjunction with redevelopment of this block, it would acquire an easement and/or right-of-way to connect the alley from its current southern terminus east to S Main Avenue. The City would also make the improvements to the alley south of the project site (approximately 270 feet) to S Main Avenue. The project is anticipated to generate 950 vehicle trips per day, with 58 occurring during the AM peak hour, and 92 occurring during the PM peak hour, and is expected to increase intersection volumes in the site vicinity by 4.3% or less during the AM and PM peak hours. With the added alley connection and additional project-generated trips, all movements at the alley intersections with S 2"' Street and S Main Avenue are expected to operate at LOS B or better. Transit service and non-motorized facilities are adequate to accommodate transit and non-motorized trips generated by the project. Based on these analyses, the project would not require any off-site transportation mitigation. The transportation impact fee for the proposed project is estimated to be $112,378.25 based on the development program evaluated herein. JAB/tsm Renton Her!lage Apts_ rransportatian !mpacr AnaljSIS -DRAFr.oocx heffron -14 -June 17, 2014 IMMMeAH,MMMIMM,MeWIM i! i;,' (! i;! -,i:)) GEOTECHNICAL ENGINEERING STUDY Proposed Mixed-Use Building 207-219 Main Avenue South Renton, Washington This report presents the findings and recommendations of our geotechnical engineering study for the site of the proposed mixed-use building to be located in Renton. We were provided with site plans and a topographic map. TSA Architects developed these plans, which are dated March 8, 2007. The topographic map shows the buildings and structures on and near the subject site, 2-foot contour intervals have also been mapped, and the relationship between the property and the intersecting streets, Main Avenue South and South 2nd Street are also shown. Based on these plans, we understand that the building will consist of 5 stories of residential apartments aver a ground-level parking and retail area and one level of below ground parking. The project will cover the majority of the site and we anticipate cuts on the order of 10 to 12 feet. If the scope of the project changes from what we have described above, we should be provided with revised plans in order to determine if modifications to the recommendations and conclusions of this report are warranted. SITE CONDITIONS SURFACE The Vicinity Map, Plate 1, illustrates the general location of the site. The property is rectangular in shape and consists of four lots at the southwest corner of Main Avenue South and South 2nd Street in Renton. The northern half of the site, at one time a gas station, is still occupied by the pump canopy and the shop building. The gas tanks an the southern portion of the northern parcel were removed in the past. Currently, the building is occupied by a coffee shop and the southern half of the site is undeveloped and being used as a parking lot. The site is flat and the northern half is paved while the southern half is gravel. An 11-foot-wide alley bounds the site to the west and South 2nd Street and Main Avenue South bounds the site to the north and east. On the western side of the alley are three CMU office buildings. The northernmost building is a tall one-story, is located approximately 11 feet from the site, and has a finished floor elevation several feet below the alley grade The central building is located approximately 25 feet from the site and is one story tall. The southern building is two stories over a basement that has a finished floor approximately 4 to 5 feet below the alley grade. A tall one-story CMU building sits on the common property line to the south. Its finished fioor elevation is near the existing site grade. Several large cracks are visible on the north-facing wall of this building, and it appears that the eastern end of the building has settled severely relative to its western end. SUBSURFACE The subsurface conditions were explored by drilling seven borings at the approximate locations shown on the Site Exploration Plan, Plate 2. Our expioration program was based an the proposed GEO TECH CONSUL 7 ANTS. INC. N & C Investments, LLC. July 18, 2007 JN 07190 Page 2 construction, anticipated subsurface conditions and those encountered during exploration, and the scope of work outlined in our proposal. The seven borings were drilled on June 15 and 16, 2007 using a truck-mounted, hollow-stem auger drill. Samples were taken at 2.5-to 5-foot intervals with a standard penetration sampler. This split- spoon sampler, which has a 2-inch outside diameter, ·1s driven into the soil with a 140-pound hammer falling 30 inches. The number of blows required to advance tho sampler a given distance is an indication of the soil density or consistency. A geolechnical engineer from our staff observed the drilling process, logged the test borings, and obtained representative samples of the soii encountered. The Test Boring Logs are attached as Plates 3 through 10. Soil Conditions In all seven of our borings we observed fill soils overlying loose to medium-dense, alluvial (water deposited) sand and gravels. The depth at which the native sand and gravels became dense varied across the site but typically was from approximately 20 to 25 feet below the existing grade except in boring 8-5, near the northwest corner of the site, where dense soil was not encountered until 32 feet. The maximum explored depth of our borings was 39 feet. Typically the fill soil on the site was up to 3 feet thiGk, except in boring B-7, drilled near the center of the northern half of the property where the previous gas station tanks were removed, here we encountered approximately 15 feet of fill. Large gravels and cobbles were common to all of our borings. No obstructions were revealed by our explorations. However, debris, buried utilities, and old foundation and slab elements are commonly encountered on sites that have had previous development. Groundwater Conditions Groundwater seepage was observed at a depth of 20 to 26 /eel. The borings were left open for only a short time period. Therefore, the seepage levels on the logs represent the location of transient water seepage and may not indicate the static groundwater level. Groundwater levels encountered during drilling can be deceptive, because seepage into the boring can be blocked or slowed by the auger itself. 11 should be noted that groundwater levels vary seasonally with rainfall and other factors. We anticipate that groundwater could be found in more permeable soil layers and between the near-surface weathered soil and the underlying denser soil. The stratification lines on the logs represent the approximate boundaries betv,een soil types at the exploration locations. The actual transition between soil types may be gradual, and subsurface conditions can vary between exploration iocations. The logs provide specific subsurface information only at the locations tested. If a transition in soil type occurred between samples in the borings, the depth of the transition was interpreted. The relative densities and moisture descriptions indicated on the boring logs are in\erpretive descriptions based on the conditions observed during drilling. GEOTECH CONSULTANTS, INC. N & C Investments, LLC. July 18, 2007 GENERAL CONCLUSIONS AND RECOMMENDATIONS JN 07190 Page 3 THIS SECTION CONTAINS A SUMMARY OF OUR STUDY AND FINDINGS FOR THE PURPOSES OF A GENERAL OVERVIEW ONLY. MORE SPECIFIC RECOMMENDATIONS AND CONCLUSIONS ARE CONTAINED IN THE REMAINDER OF THIS REPORT. ANY PARTY REL YING ON THIS REPORT SHOULD READ THE ENTIRE DOCUMENT The site is underlain by loose to medium-dense, alluvial (water deposited) sand and gravel. The soil became dense at 20 to 25 feet below the existing grade except the northwest corner where dense soil was encountered near 32 feet. The loose soils are compressible under the anticipated building loads and would be potentially liquefiable below the water table. Due to the size of the proposed structure, we recommend that the proposed building be supported on deep foundations embedded into the dense to very dense, native soils. Due to the presence of potentially caving near-surface soils and groundwater, it appears that augercast piers are the most suitable deep foundation option. We understand that the proposed building will have an underground garage for parking. This will require large cuts to be made close to the property line. As mentioned above the upper soils are loose and prone to caving; therefore, cuts in this type of sand and gravel should be limited to an inclination of 1.5:1 (Horizontal:Vertical). If these excavation inclinations cannot be maintained within the site boundaries, an easement could be sought from the adjacent property owners. It easements cannot be obtained or if they are not feasible then a temporary shoring system will have t.o be designed. Based on the current plans, it appears that shoring will be necessary along each sia'e of the excavation. The adjoining southern building was constructed on conventional, shallow foundations and has already experienced severe post-construction settlement Prior to beginning excavation the northern wall of th'1s building will need to be underpinned lo avoid settlement due to the adjacent proposed excavation. Based on our experience in the vicinity, we recommend that this building be underpinned by using small-diameter, driven pipe-piles. The upper soils are prone to caving a~d the presence of large cobbles and boulders makes the installation of soldier piles with lean-mix cement very difficult and unpredictable. Therefore, the drilled shoring piles are no( the recommended underpinning system for the southern adjacent building. Soldier piles can, however, be used as temporary shoring for the excavation. The minimum underpinning pile length will be dependent on the driving refusal of the piles, but the piles should be embedded into the dense sand and gravels below the lowest excavation elevation to ensure that no loads from the neighboring building are transmitted to this project's shoring or permanent beiow-grade walls. GEOTECH CONSUL TAN TS. INC N & C Investments, LLC. July 18, 2007 JN 07190 Page 4 Slabs-on-grade floors may also experience noticeable differential settlement relative to the foundations. If some settlement is acceptable a slab-on-grade could be used for the garage floors. This slab should be reinforced with steel bars to limit the potential for excess cracking when settlement occurs. A minimum reinforcement of No. 4 rebar placed on 18-inch centers each way in the slab is typically sufficient. Wherever possible the slab should be isolated from the pier- supporled walls and columns. An exception to this is whern interior and exterior slabs and walk ups lead to doorways. At these locations, the slab's reinforcement should be tied to the pier- supported foundations. This lessens the chance that a sharp downset {i.e., trip hazard) will form at the door threshold. The adjacent structures are likely supported on conventional foundations that bear on compressible soils. As a result, it is likely that they have undergone excessive settlement already. There is always some risk associated with demolition and foundation construction near structures such as this. It is imperative that unshared excavations do not extend below a 2:1 (Horizontal:Vertical) imaginary bearing zone sloping downward from existing footings. Contractors working on. the demolition and construction of the building must be cautioned to avoid strong ground vibrations, which could cause additional settlement in the neighboring foundations. During demolition, strong pounding on the ground with the excavator, which is often used lo break up debris and concrete, should not occur. Large equipment and vibratory compactors should not be used close to the south property line. Additionally, in order to protect yourselves from unsubstantiated damage claims from the adjacent owners, 1) the existing condition of the foundation should be documented before starting demolition, and 2) the footings should be monitored for vertical movement during the demolition, excavation, and construction process. These are common recommendations for projects located close to existing structures that may bear on loose soil and have already experienced excessive settlement. We can provide additional recommendations for documentation and monitoring of the adjacent structures, if desired. Storm detention/retention facilities and other utilities are often installed below, or near, structures. The walls of storm vaults must be designed as etther cantilever or restrained retaining walls, as appropriate. Wall pressures for the expected soil conditions are presented in the permanent foundation and retaining walls section of this report. It is important that the portion of the structure above the permanent detained water level be backfilled with free-draining soil, as recommended for retaining walls. Should drainage not be provided, the walls must be designed for hydrostatic forces acting on the outside of the structure. The backfill for all underground structures must be compacted in lifts according to the criteria in the pervious section of this report. Trenches for underground structures and utilities should not cross a line extending downwards from an existing footing at an inclination of (2: 1) (Horizontal:Vertical), or a line extending downwards from a property line at an inclination of (1.5:1) (H:V). We should be consulted if these excavation zones will be exceeded for installation of storm facilities or other utilities. If the structure includes an elevator, it may be necessary to provide special drainage or waterproofing measures for the elevator pit. If no seepage into the elevator pit is acceptable, it will be necessary to provide a footing drain and free-draining wall backfill, and the walls should be waterprocfed. If the footing drain will be too low to connect to the storm drainage system, then it will likely be necessary to install a pumped sump to discharge the collected water. Alternatively, the elevator pit could be designed to be entirely waterproci; this would include designing the pit structure to resist hydrostatic uplift pressures. The erosion control measures needed during the site development will depend heavily on the weather conditions that are encountered. While site clearing will expose a large area of bare soil, the erosion potential on the site is relatively low due to 1he sandy soil conditions and the excavation GEOTECH CONSULTANTS, INC N & C Investments, LLC. July 18, 2007 JN 07190 Page 5 being lower than the surrounding area. Rocked construction access roads should be extended into the site to reduce the amount of soil or mud carried off the property by trucks and equipment. Wherever possible, these roads should follow the alignment of planned pavements, and trucks should not be allowed to drive off of the rock-covered areas. Cut slopes and soil stockpiles should be covered with plastic during wet weather. Following rough grading, it may be necessary to mulch or hydroseed bare areas that will not be immediately covered with landscaping or an impervious surface. The drainage and/or waterproofing recommendations presented in this report are intended only to prevent active seepage from flowing through concrete walls or slabs. Even in the absence of active seepage into and beneath structures, water vapor can migrate through walls, slabs, and floors from the surrounding soil, and can even be transmitted from slabs and foundation walls due to the concrete curing process. Water vapor also results from occupant uses, such as cooking and bathing. Excessive water vapor trapped within structures can result in a variety of undesirable conditions, including, but not limited to, moisture problems with flooring systems, excessively moist air within occupied areas, and the growth of molds, fungi, and other biological organisms that may be harmful to the health of the occupants. The designer or architect must consider the potential vapor sources and likely occupant uses, and provide sufficient ventilation, either passive or mechanical. to prevent a build up of excessive water vapor within the planned structure. Geotech Consultants, Inc. should be allowed to review the final development plans to verify that the recommendations presented in this report are adequately addressed in the design. Such a plan review would be additional work beyond the current scope of work for this study, and it may include revisions to our recommendations to accommodate site, development, and geotechnical constraints that become more evident during the review process. We recommend including this report, in its entirety, in the project contract documents. This report should also be provided to any future property owners so they will be aware of our findings and recommendations. SEISMIC CONS/DERA T/ONS In accordance with Table 1613.5.2 of the 2006 International Building Code {!BC), the site soil profile within 1 DO feet of the ground surface is best represented by Soil Profile Type D (Stiff Soil Profile. The augercast foundation piers, recommended in this report, will be embedded into dense, non-liquefiable soils. AUGERCAST CONCRETE PIERS Augercast piers are installed using continuous flight. hollow-stem auger equipment mounted on a crane. Concrete grout must be pumped continuously through the auger as it is withdrawn. This allows the piers to be installed where caving conditions or significant groundwater are anticipated. We recommend that augercast piers be installed by an experienced contractor who is familiar with the anticipated subsurface conditions. An allowable compressive capacity of 35 tons can be attained by installing a 16-inch-diameter, augercast concrete pier at least 10 feet into dense, native sand and gravel. For transient loading, such as wind or seismic loads, the allowable pier capacity may be increased by one-third. We can provide design criteria for different pier diameters and embedment lengths, if greater capacities are GEOTECH CONSUcTANTS, INC. N & C Investments, LLC. July 18, 2D07 JN 07190 Page 6 required. The minimum center-to-center pier spacing should be three times the pier diameter. Based on our boring information, we estimate that pier lengths of about 35 to 40 feet will be required to achieve adequate pe~etration into the bearing soil. We estimate that the total settlement of single piers installed as described above will be on the order of one-halt inch. Most of this settlement should occur dunng the construction phase as the dead loads are applied. The remaining post-construction settlement would be realized as the live loads are applied. We estimate that differential settlements over any portion of the structures should be less than about one-quarter inch. We recommend reinforcing each pier its entire length. This typically consists of a rebar cage extending a portion of the pier's length with a full-length center bar. Each pier can be assumed to have a point of fixity (poin1 of maximum bending moment) at 12 feet below the top of the pier for design of the reinforcing. The loose soil against the piers can be assumed to have a design passive earth resistance of 200 pounds per cubic foot (pcf) acting on two times the pier diameter. Passive earth pressures on the grade beams will also provide some lateral resistance. If structural fill is placed against the outside of the grade beams, the design passive earth pressure from the fill can be assumed to be equal to that pressure exerted by an equivalent fiuid with a density of 200 pcf. This passive resistance is an ultimate value that does not include a safety factor. PIPE PILES This section applies to our recommendations for the underpinning of the adjacent building south of the subject property. Three-or 4-inch-diameter pipe piles driven with a 650-or 800-or 1, 1 DO- pound hydraulic jackhammer to the following final penetration rates may be assigned the following compressive capacities. --lNSJUli PILE .. , J)IAMETER I ' . FINAL DRIVING RATE {90·µound h.tm111l!r) , I NIA FINAL DRIVING RATE (650-poun<l ha111m1:r) . ' ' ' FINAL DRIVING RATE (BOO-round hunun0r) 6 socltnch 10 sec/inch FINAL DRIVING RATE (I, I OO-pou11d 11.in,ml;'r) 6 sec/inch ALLOWAJll,E CO,\IPRESSIVE CAPACITY .. 6 tons Note: The refusal criteria indicated in Iha above table are valid only for pipe piles that are installed using a hydraulic impact hammer carried on leads that allow the hammer to sit on the lop of the pile during driving. If the piles are inslalied by alternative methods, such as a vibra1ory hammer or a hammer 1hat is hard-mounted to lhe Installation machine, numerous load tests to 200 percent of the design capacity would be necessary to substantiate the allowable pile load. The appropriate number of load tests would need to be determined at the lime the contractor and installation method are chosen. As a minimum, load tests on 20 percent of the piles is typical where alternative pile installalion methods are used. As a minimum, Schedule 40 pipe should be used. The si1e soils should not be highly corrosive. Considering this, it is our opinion that standard "black" pipe can be used, and corrosion protection, such as galvanizing, is not necessary for the pipe piles. Based on the planned excavation depth and our borings, we recommend a minimum pile length of 20 feet to achieve embedment into dense, native soils. Our experience with installation of small· diameter pipe piles indicates that it is likely that the piles will be longer than this minimum length. GEOTECH CONSULTANTS. INC. N & C Investments, LLC July 18, 20C7 JN 07190 Page 7 Pile caps, grade beams, or brackets should be used to transmit loads to the piles. Isolated pile caps should include a minimum of two piles to redi;ce the potential for eccentric loads being applied to the piles. Subsequent sections of pipe can be connected with slip or threaded couplers, or they can be welded together. If slip couplers are used, they should fit snugly into the pipe sections. This may require that shims be used or that beads of welding flux be applied to the outside of the coupler. PERMANENT FOUNDATION AND RETAINING WALLS Retaining walls backfilled on only one side should be designed to resist the lateral earth pressures imposed by the soil they retain. The following recommended parameters are for walls that restrain level backfill: --r-----T-r,\IUMlcTER \'ALUE ' ! Active Earth Pressure • 35 pcf Passive Earth Pressure 300 pcf Soil Unit Weight 130 pcf When'.!: {i) pcf is pounds per cublc foot, and (JI) active and passive earth pressures are t;omputed using the equivalent fluid pressures. • For a reslrained wall that cannot deflect at least 0.002 times its height, a uniform lateral prusure equal to 10 psf times the height o1 the wall should be added to the above aci:lve equivalent fluid pressure. The values given above are to be used to design permanent foundation and retaining walls only. The passive pressure given is appropriate for the depth of level structural fill placed in front of a retaining or foundation wall only. The value for passive resistance is an ultimate value and does not include a safety factor. We recommend a safety factor of at least 1 5 for overturning and sliding, when using the above values to design the walls. Restrained wall soil parameters should be utilized for a distance of 1.5 times the wall height from corners or bends in the walls. This is intended to reduce the amount of cracking that can occur where a wall is restrained by a comer. The design values given above do not include the effects of any hydrostatic pressures behind the walls and assume that no surcharges, such as those caused by slopes, vehicles, or adjacent foundations will be exerted on the walls. If these conditions exist, those pressures should be added to the above lateral soil pressures. Where sloping backfill is desired behind the walls, we will need to be given the wall dimensions and the slope of the backfill in order to provide the appropriate design earth pressures. The surcharge due to traffic loads behind a wall can tyoically be accounted for by adding a uniform pressure equal to 2 feet multiplied by the above active fluid density. Heavy construction equipment should not be operated behind retaining and foundation walls within a distance equa: to the height of a wall, unless the walls are designed for the additional lateral pressures resulting from the equipment. The wall design criteria assume that the backfill will be well-compacted in lifts no t:iicker than 12 inches. The compaction of backfill near the walls should GEOTECH CONSULTANTS. INC. N & C Investments, LL C. July 18, 2007 JN07190 Page 8 be accomplished with hand-operated equipment to prevent the walls frori being overloaded by the higher soil forces that occur during compaction. Retaining Wall Bar;i<fi/1 and Waterproofing Backfill placed behind retaining or foundation walls should be coarse, free-draining structural fill containing no organi~s. This backfill should contain no more than 5 percent silt or clay particles and have no gravel greater than 4 inches in diameter. The percentage of particles passing the No. 4 sieve should be between 25 and 70 percent. If the native sand and gravel is used as backfill, a drainage composite similar to Miradrain 6000 should be placed against the backfilled retaining walls. The drainage composites should be hydraulically connected to the foundation drain system. Free-draining backfill or gravel should be used for the entire width of the backfill where seepage is encountered. For increased protection, drainage composites should be placed along cut slope faces, and the walls should be backfilled entirely with free-draining soil. The later section entitled Drainage Considerations should also be reviewed for recommendations related to subsurface drainage behind foundation and retaining walls. The purpose of these backfill requirements is to ensure that the design criteria for a retaining wall are not exceeded because of a build-up of hydrostatic pressure behind the wall. The top 12 to 18 inches of the backfill should consist of a compacted, relatively impermeable soil or topsoil, or the surface should be paved. The ground surface must also slope away from backfilled walls to reduce the potential for surface water to percolate into the backfill. The section entitled General Earthwork and Structural Fill contains recommendations regarding the placement and compaction of structural fill behind retaining and foundatior walls. The above recommendations are not intended to waterproof below-grade walls. or to prevent the formation of mold, mildew or fungi in interior spaces. Over time, the performance of subsurface drainage systems can degrade, subsurface groundwater flow patterns can change, and utilities can break or develop leaks. Therefore, waterproofing should be provided where future seepage through the walls is not acceptable. This typically includes limiting cold-joints and wall penetrations, and using bentonite panels or membranes on the outside of the walls. There are a variety of different waterproofing materials and systems, which should be installed by an experienced contractor familiar with the anticipated construction and subsurface conditions. Applying a thin coat of asphalt emulsion to the outside face of a wall is not considered waterproofing, and will only help to reduce moisture generated from water vapor or capillary action from seeping through the concrete. As with any project, adequate ventilation of basement and crawl space areas is important to prevent a build up of water vapor that is commonly transmitted through concrete walls from the surrounding soil, even when seepage is not present. This is appropriate even when waterproofing is applied to the outside of foundation and retaining walls. We recommend that you contact a specialty consultant if detailed recommendations or specifications related to waterproofing design, or minimizing the potential for infestations of mold and mildew are desired. The General, Slabs-On-Grade, and Drainage Considerations sections should be reviewed for additional recommendations related to the control of groundwater and excess water vapor for the anticipated construction. r.:;FOTFr.H CONS! Jl T ANTS INr. N & C Investments, LLC. Ju!y 18, 2007 SLABS-ON-GRADE JN 07190 Page 9 If some potential for post construction settlement and cracking can be to:erated, the garage floors can be constructed as slabs-on-grade atop a minimum of 12 inches of compacled structural fill over native soils.,. To reduce the magnitude of the slab cracking we recommend reinforcing the slabs with a minimum of No. 4 reba r piaced on 18-inch centers each way. The subgrade soil must be in a fimn, non-y'elding condition at the time of slab constnuction or underslab :'ill placement. Any soft areas encountered should be excavated and replaced with additional select, imported structural fill. Living space slabs and slabs where no potential for settlement is acceptable should be structurally supported by the piling Even where the exposed soils appear dry, water vapor will tend to naturally migrate upward through the soil to the new constructed space above it. All interior slabs-on-grade must be underlain by a capillary break or drainage layer consisting of a minimum 4-inch thickness of grave! or crushed rock that has a fines content (percent passing the No. 200 sieve) of less than 3 percent and a sand content (percent passing the No. 4 sieve) of no more than 10 percent. This capillary break/drainage layer is not necessary if an underslab drainage system is installed. As noted by the American Concrete Institute (ACI) in the Guides for Concrete Floor and Slab Structures, proper moisture protection is desirable immediately below any on-grade slab that will be covered by tile, wood, carpet, impemneable floor coverings, or any moisture-sensitive equipment or products. ACI also notes that vapor retarders, such as 6-mil plastic sheeting, are typically used. A vapor retarder is defined as a material with a permeance of less than 0.3 US pemns per square loot (psi) per hour, as determined by ASTM E 96. It is possible that concrete admixtures may meet this specification, although the manufacturers of the admixtures should be consulted. Where plastic sheeting is used under slabs, joints should over1ap by at least 6 inches and be sealed with adhesive tape. The sheeting should extend to the foundation walls for maximum vapor protection. If no potential for vapor passage through the slab is desired, a vapor barrier should be used. A vapor barrier, as defined by ACI, is a product with a water transmission rate of 0.00 perms per square foot per hour when tested in accordance with ASTM E 96. Reinforced membranes having sealed overlaps can meet this requirement. In the recent past, ACI (Section 4.1.5) recommended that a minimum of 4 inches of well-graded compactable granular material, such as a 518 inch minus crushed rock pavement base, should be placed over the vapor retarder or barrier for protection of the retarder or barrier and as a "blotter" to aid in the curing of the concrete slab. Sand was not recommended by ACI for this purpose. However, the use of material over the vapor retarder is controversial as noted in current ACI literature because of the potential that the protection/blotter material can become wet between the time of its placement and the installation of the slab. If the material is wet prior to slab placement, which is always possible in the Puget Sound area, it could cause vapor transmission to occur up through the slab in the future, essentially destroying the purpose of the vapor barrier/retarder. Therefore, if there is a potential that the protection/blotter material will become wet before the slab is installed, ACI ~ow recommends that no protection/blotter material be used. However, ACI then recommends that, because there is a potential for slab cure due to the loss of the blotter material, joint spacing in the slab be reduced, a low shrinkage concrete mixture be used, and "other measures" (steel reinforcing, etc.) be used. ASTM E-1643-98 "Standard Practice for Installation of Water Vapor Retarders Used in Contact with Earth or G,anular Fill Under Concrete Slabs" generally agrees with the recent ACI literature. We recommend that the contractor, the project materials engineer. and the owner discuss these issues and review recent AC! literature and ASTM E-1643 for installation guidelines and guidance GEOTECH CONSULTANTS INC. N & C Investments, LL C. July 18, 2007 JN 07190 Page 10 on the use of the protec1ion/blotter material. Our opinion is that with impervious surfaces tha1 all means should be undertaken to reduce water vapor transmission The General, Permanent Foundation and Retaining Walls, and Drainage Considerations sec1ions should be reviewed for additional recommenda1ions related to the control of groundwater and excess water vapor for the anticipated construction. Isolation joints should be provided where the slabs intersect columns and walls. Control and expansion joints should also be used to control cracking from expansion and contraction. Saw cuts or preformed strip joints used to control shrinkage cracking should extend through the upper one- fourth of the slab. The spacing of control or expansion joints depends on the slab shape and the amount of steel placed in it. Reducing the water-to-cement ratio of the concrete and curing the concre1e, by preventing the evaporation of free water until cement hydration occurs, will also reduce shrinkage cracking. EXCAVA T/ONS AND SLOPES Excavation slopes should not exceed the limits specified in local, state, and national government safety regulations. Temporary cuts to a depth of about 4 feet may be attempted vertically in unsaturated soil, if there are no indications of slope instability. However, vertical cuts should not be made near property boundaries, or existing utilities and structures. Based upon Washington Administrative Code (WAC) 296, Part N, the soil at the subject site would generally be classified as Type C. Therefore, temporary cut slopes greater than 4 fee1 in height should not be excavated at an inclination steeper than 1.5:1 (Horizontal:Vertical), extending continuously between the top and the bottom of a cut. In addition, no unshared cuts should be made within a 2:1 (H:V) inclination of any existing footings. The above-recommended temporary slope inclination is based on the conditions exposed in our explorations, and on what has been successful at other sites with similar soil conditions. It is possible that variations in soil and groundwater conditions will require modifications to the inclination at which temporary slopes can stand. Temporary cuts are those that will remain unsupported for a relatively short duration to allow for the construction of foundations, retaining walls, or utilities. Temporary cut slopes should be protected with plastic sheeting during wet weather. It is also important that surface water be directed away from 1emporary slope cuts. The cut slopes should also be backfilled or retained as soon as possible to reduce the potential for instability. Please note that loose soil can cave suddenly and without warning. Excavation, foundation, and utility contractors should be made especially aware of this potential danger. These recommendations may need to be modified if the area near the potential cuts has been disturbed in the past by utility installation, or if settlement-sensitive utilities are located nearby. All permanent cuts into native soil should be inclined no steeper than 2:1 (H:V). To reduce the potential for shallow sloughing, fill must be compacted to the face of these slopes. This can be accomplished by overbuilding the compacted fill and then trimming it back to its final inclination. Adequate compaction of the slope face is important 'or long-term stability and is necessary to prevent excessive settlement of patios, slabs, foundations, or other improvements that may be placed near the edge of the slope. Water should not be allowed to flow uncontrolled over the top of any temporary or penmanent slope. All permanently exposed slopes should be seeded with an appropriate species of vegetation to reduce erosion and improve the stability of the surficial layer of soil. r.;FOTFr.H r.(}NSI JI T ANTS INr. N & C lnves/menls, LLC. July 18, 200-f TEMPORARY SHORING JN07190 Page 11 A variety of shoring systems are feasibie for use at this site. This section presents design considerations for cantilevered or tied-back soldier-pile walls. Since the most suitable choice is primarily dependent on a number of factors under the contractor's control, we suggest that the contractor work closely with the structural engineer during the shoring design. As discussed above, the sensitivity of adJacent buildings and utilities must be considered in the design to reduce the risk of causing settlement of these adjacent elements. Regardless of the system used, all shoring systems will deflect in toward the excavation. Therefore, there is always a risk of noticeable settlement occurring on the ground behind the shoring wall. These risks are reduced, but not entirely eliminated, by using more rigid shoring systems, such as soldier piles The shoring design should be submitted to Geotech Consultants, Inc. for review prior lo beginning site excavation. We are available and would be pleased to assist in this design effort. CANTILEVERED AND TIED-BACK SOLDIER PILES Soldier-Pile Installation Soldier-pile walls would be constructed after making planned cut slopes, and prior lo commencing the mass excavation, by setting steel H-beams in a drilled hole and grouting the space between the beam and the soii with concrete for the entire height of the drilled hole. We anticipate that the holes would require casing, the contractor should be prepared to case the holes or use the slurry method if caving soil is encountered. Excessive ground loss in t~e drilled holes must be avoided to reduce the potential for settlement on adjacent properties. If water is present in a hole at the time the soldier pile is poured, concrete must be tremied to the bottom of the hole. As excavation proceeds downward, the space between the piles should be lagged with timber, and any voids behind the timbers should be filled with pea gravel, or a slurry comprised of sand and fly ash. Treated lagging is usually required for permanent walls, While untreated lagging can often be utilized for temporary shoring walls. Temporary vertical cuts will be necessary between the soldier piles for the Jagging placement. The prompt and careful installation of lagging is important, particularly in loose or caving soil, to maintain the integrity of the excavation and provide safer working conditions. Additionally, care must be taken by the excavator to remove no more soil between the soldier piles than is necessary to install the lagging. Caving or overexcavation during lagging placement could result in loss of ground on neighboring properties. Timber lagging should be designed for an applied lateral pressure of 30 percent of the design wall pressure, if the pile spacing is less than three pile diameters. For larger pile spacings, the lagging should be designed for 50 percent of the design load. If permanent building walls are to be constructed against the shoring walls, drainage should be provided by attaching a geoiextile drainage composite with a solid plastic backing, similar to Miradrain 6000, lo the entire face of the lagging, prior to placing waterproofing and pouring the foundation wall. These drainage composites should SEOTECH CO!'\SULTANTS. INC. N & C Investments, LLC. July 18, 2007 JN07190 Page 12 be hydraulically connected to the foundation drainage system through weep holes placed in the foundation walls. Soldier-Pile Wall Design Temporary soldier-pile shoring that is cantilevered or restrained by one row of tiebacks, and that has a level backslope, should be designed for an active soil pressure equal to that pressure exerted by an equivalent fluid with a unit weight of 35 pounds per cubic foot (pcf). For the shoring along the southern property line adjacent to the exisung building, we recommend that an at rest soil pressure of 55 pcf be utilized in the shoring design to reduce the lateral deflections in this wall. Traffic surcharges can typically be accounted for by increasing the effective height of the shoring wall by 2 feet. Existing adjacent buildings will exert surcharges on the proposed shoring wall, unless the buildings are underpinned. Slopes above the shoring walls will exert additional surcharge pressures. These surcharge pressures will vary, depending on the configuration of the cut slope and shoring wall. For a 1.5:1(H:V) cut slope above the shoring a uniform lateral surcharge nf 20(S) psf should be applied (where S is the height oi the cut slope in feet). We can provide recommendations regarding building surcharge pressures if necessary when the preliminary shoring design is completed. It is imporiant that the shoring design provides sufficient working room ta drill and install the solaier piles, without needing to make unsafe, excessively steep temporary cuts. Cut slopes should be planned to intersect the backside of the drilled holes, not the back of the lagging. Lateral movement of the soldier piles below the excavation level will be resisted by an ultimate passive soil pressure equal to that pressure exerted by a fiuid with a density of 350 pcf. No safety factor is included in the given value. This soil pressure is valid only for a level excavation in front of the soldier pile; it acts on two times the grouted pile diameter. C,1t slopes made in front of shoring walls significantly decrease lhe passive resistance. This includes temporary cuts necessary to install internal braces or rakers. The minimum embedment below the floor of the excavation for cantilever soldier piles should be equal to the height of the "stick-up." Tied-back soldier piles should be embedded no less than 10 feet below the lowest point of the excavation, including footing and utility excavations. The vertical capacity of soldier piles lo carry the downward component of the tieback forces will be developed by a combination of frictional shaft resistance along the embedded length and pile end-bearing. -2'1@M#M ...... 1Wfrtlf'ff .. ~ile Shaft Fric\i~ 800 psf _j Where: (f) psf is pounds per square foot The above values assume that the excavation is level in front of the soldier pile and that the bottom of the pile is embedded a minimum of 10 feet below the floor of the excavation. The concrete surrounding the embedded portion of the pile must have C:::Fnn:r.H r.nN_c;111 TANT<:; !Nr. N & C Investments, I.LC. July 18, 2007 JN07190 Page 13 sufficient bond and stength to transfer the vertical load from the steel section through the concrete into the soil. EXCAVATION AND SHORING MONITORING As with any shoring system, there is a potential risk of greater-than-anticipated movement of the shoring and the ground outside of the excavation. This can translate into noticeable damage of surrounding on-grade elements, such as foundations and slabs. Therefore, we recommend making an extensive photographic and visual survey of the project vicinity, prior to demolition activities, installing shoring or commencing excavation. This documents the condition of buildings, pavements, and utilities in the immediate vicinity of the site in order to avoid, and protect the owner from, unsubstantiated damage claims by surrounding property owners. Additionally, the shoring walls, and any adjacent foundations should be monitored during construction to detect soil movements. To monitor their performance, we recommend establishing a series of survey reference points to measure any horizontal deflections of the shoring system. Control points should be established at a distance well away from the walls and slopes, and deflections from the reference points should be measured throughout construction by survey methods. At least every third soldier pile should be monitored by taking readings al the top of the pile. Additionally, benchmarks installed on the surrounding buildings should be monitored for at least vertical movement. We suggest taking the readings at least once a week, until it is established that no deflections are occurring. The initial readings for this monitoring should be taken before starting any demolition or excavation on the site. DRAINAGE CONSIDERA T/ONS We anticipate that permanent foundation walls (will/may) be constructed against the shoring walls. Where this occurs, a plastic-backed drainage composite, such as Miradrain, Battledrain, or similar, should be placed against the entire surface of the shoring prior to pouring the foundation wall. Weep pipes located no more than 6 feet on-center should be connected to the drainage composite and poured into the foundation walls or the perimeter footing. A footing drain installed along the inside of the perimeter footing will be used to collect and carry the water discharged by the weep pipes to the storm system. Isolated zones of moisture or seepage can still reach the permanent wall where groundwater finds leaks or joints in the drainage composite. This is often an acceptable risk in unoccupied below-grade spaces, such as parking garages. However, formal waterproofing is typically necessary in areas where wet conditions at the face of the permanent wall will not be tolerable. If this is a concern, the permanent drainage and waterproofing system should be designed by a specialty consultant familiar with the expected subsurface conditions and proposed construction. Footing drains placed inside the building or behind backfilled walls should consist of 4-inch, perforated PVC pipe surrounded by at least 6 inches of 1-inch-minus, washed rock wrapped in a non-woven, geotextile filter fabric (Mirafi 140N, Supac 4NP, or similar material). At its highest point, a perforated pipe invert should be al least 6 inches below the level of a crawl space or the bottom of a floor slab, and it should be sloped slightly for drainage. Plate 11 presents typical considerations for footing drains. All roof and surface water drains must be kept separate from the foundation drain system. GEOTECH CONSULTANTS. INC. N & C Investments, LL C. Jury 18. 2007 JN 07190 Page 14 If the structure includes an elevator, it may be necessary 1o provide special drainage or wa1erproofing measures for the elevator pii. If no seepage into the elevator pit is acceptable, it will be necessary to provide a footing drain and free-draining wall backfill, and the walls should be waterproofed. If the footing drain will be too low 10 connect to the storm drainage system, then it will likely be necessary to install a pumped sump to discharge the collected water. Alternatively, the elevator pit could be designed to be entirely waterproof; this would include designing the pit structure 1o resist hydrostatic uplift pressures. Groundwa1er was observed during our field work. If seepage is encoun1ered in an excavation, it should be drained from the site by directing it through drainage ditches, perforated pipe, or French drains, or by pumping it from sumps interconnected by shallow connector trenches at the bottom of the excavation. The excavation and site should be graded so that surface water is directed off the site and away from the tops of slopes. Water should not be allowed to stand in any area where foundations. slabs, or pavements are to be constructed. Final site grading in areas adjacent to the building should slope away at least 2 percent, except where the area is paved. Surface drains should be provided where necessary to prevent ponding of water behind foundation or retaining walls. GENERAL EARTHWORK AND STRUCTURAL FILL All building and pavement areas should be stripped of surface vegetation, topsoil, organic soil, and other deleterious material. The stripped or removed materials should not be mixed with any materials to be used as structural fill, but they could be used in non-structural areas, such as landscape beds. Structural fill is defined as any fill, including utility backfill, placed under, or close to, a building, behind permanent retaining or foundation walls, or in other areas where the underlying soil needs to support loads. Ali structural fill should bo placed in horizontal lifts with a moisture content at, or near, the optimum moisture content. The optimum moisture content is that moisture content that results in the greatest compactec dry density. The moisture content of fill is very important and must be closely controlled during the filling and compaction process. The on-stte sand and gravel is well suited for reuse as structural fill. The allowable thickness of the fill lift will depend on the material type selected, the compaction equipment used, and the number of passes made to compact the lift. The loose lift thickness should not exceed 12 inches. We recommend testing the fill as it is placed. If the fill is not sufficiently compacted, it can be recompacted before another lift is placed. This eliminates the need to remove the fill to achieve the required compaction. The following table presents recommended relative compactions for structural fill: (;FOTFr.H r:nNSI 11 IANT,c:; !hlf": N & C Investments, LLC. July 18, 2007 1,ocA·~~IUM m,t.ATl\'t: l'LACll 01\ll'ACI ION Beneath footings, slabs 95% or walkways ~ Filled slopes and behind 90% retainino w(:1115 95% for upper 12 inches of Beneath pave'llents subgrade; 90% below thal level Where: Minimum Relative Compaction is the ratio, expressed in percentages, of the compacted dry density to the maximum dry density, a.is determined in accordance with ASTM lest Designation D 1557·91 (Modified Proctor). JN07190 Page 15 Structural fill that will be placed in wet weather should consist of a coarse, granular soil with a silt or clay content of no more than 5 percent. The percentage of particles passing the No. 200 sieve should be measured from that portion of soil passing the three-quarter-inch sieve. LIM/TA TIONS The conclusions and recommendations contained in this report are based on site conditions as they existed at the time of our exploration anc assume that the soil and groundwater conditions encountered in the borings are representative of subsurface conditions on the site. If the subsurface conditions encountered during construction are significantly different from those observed in our explorations, we should be advised at once so that we can review these conditions and reconsider our recommendations where necessary. Unanticipated soil conditions are commonly encountered on construction sites and cannot be fully anticipated by merely taking soil samples in borings. Subsurface conditions can also vary between exploration locations. Such unexpected conditions frequently require making additional expendiiures to attain a properly constructed project. 11 is recommended that the owner consider providing a contingency fund to accommodate such potential extra costs and risks. This is a standard recommendation for all projects. This report has been prepared for the exclusive use of N&C Investments , and its representatives, for specific application to this project and site. Our recommendations and conclusions are based on observed site materials, and engineering analyses. Our conclusions and recommendations are professional opinions derived in accordance with current standards of practice within the scope of our services and within budget and time constraints. No warranty is expressed or implied. The scope of our services does not include services related to construction safety precautions, and our recommendations are not intended to direct the contractor's methods, techniques, sequences, or procedures, except as specifically described in our report for consideration in design. Our services also do no1 include assessing or minimizing the potential for biological hazards, such as mold, bacteria, mildew and fungi in either the existing or proposed site development. ADDITIONAL SERVICES In addition to reviewing the final plans, Geotech Consultants, Inc. should be retained to provide geotechnical consultation, testing, and observation services during construction. This is to confirm r.;cnTECH CONSULTANTS INC. N & C Investments, LLC. July 18. 2007 JN 07190 Page 16 that subsurface conditions are consistent with those indicated by our exploration. to evaluate whether earthwork and foundation construction activilies comply wit~ the general intent of the recommendations presented in this report, and to provide suggestions for design changes in the event subsurface conditions differ from those anticipated prior to the start of construclion. However, our work wou,d not include the supervision or direction of the actual work of the contractor and its employees or agents. Also, job and site safety, and dimensional measurements, will be the resoonsibility of the contractor. Durtng the construction phase, we will provide geotechnical observation and testing services when requesled by you or your representatives. Please be aware thal we can only document site work we actually observe. If is still the responsibility of your contractor or on-site construction team to verify that our recommendations are being followed, whether we are present at the site or not. The scope of our work did not include an erwironmental assessment, but we can provide this service, if requested. The following plates are attached to complete this report: Plate 1 Plate 2 Plates 3 -1 D Plate 11 Vicinity Map Site Exploration Plan Test Boring Logs Typical Footing Drain Detail We appreciate the opportunity to be of service on this project. If you have any questions, or if we may be of further service, please do not hesitate to contact us. ZJM/JHS: jyb Respectfully submitted, GEOTECH CONSULTANTS, INC. Zack J. Munstermann Geotechnical Engineer ________ ..,,....., James H. Strange, Jr., P.E. !E)(P'lij£S 01-31-Of\ J Project Manager r,FnTFGH r.nNSI H TANT.S INr: I /1 ~ I• V ~-11 ~~2T~S~IN1! ,:i,~;~;,"""l'-y::"l!!!!!! ..... ==-- VICINITY MAP 207 -219 Main Avenue South Renton, Washington I Job No: 07190 I Oate: Ju'y 2007 I Plate: j' -,·,l N I I\ South 2nd Street ~ v Legend: >, a, "' r··-··;.~·-··-··-··-··-··-··-··-··~-.. ~ 8-6 Existing Existing Building Building B-7 ~ ~ 8-1 ~ B-2 I 8-3 8-4,.. : ~ '17 '··-··-··-I·-··-··-0 ·-••-••-••-••-• ·- ..c -::, 0 U) Ql ::, C a, > <( C .. ::'!: 0 Test boring location GEOTECH CONSULTANTS, INC. :P SITE EXPLORATION PLAN 207 • 219 Main Avenue South Renton, Washington Job No: I Date: I jPtate: 07190 July 2007 No Scale 2 --... 15 ... 5 ----3 - 1 0 ..... ---4 I- 1 5 L-... --10 - 20 ----62 - 25 -.Y .... I--60 - 30 ----79/11 ... 35 ~ ... ... ... 871 -10.5 40 - BORING 1 Description "{..:,.· '• Brown SAND and gravel, mediurn-to coarse-grained, moist, loose :, ... ~ . .,c :;., t, ,"•~ ;o .. . .. () ' ob .. ~ I • ·'· ' 1 ~~.-.,,:~~~ .1.,,,\~ f~ ~'ii• •ao "' "t./Cl\1 ~". ~ .... 'l,t; " " " ~ { • q "" g ~:: ~-~ t, • '1:1·~ 1 ····« • 2 • <>J <> ·" • ,..! <I Jo ,• o"° ,~· ... t, ~-~""'"'.,0 o! ""' o: .;., '• ~'I,•"~·" ~~:: .. 'a~: o 0 o" I ~'"""' 'I 3 I '°·'··"· b"o ~ ~a., " ' . "' (J G •£>l .. / • C" r;~:-0,\ . oJ <> D : l'I• b 0 .,.~ • " ~ . .. .,J">"< • ., .. ~ ~~ •• o ..... r, r\ ·:.-:, 4 @J !, .r,;,·~' ,;, "ca"· .o", "p" 'O\ 0; • ,-• • ,, 11 ..• o,,.!,_° ,0., 5 •. , ,,,,.. .. ~:~'j,~o~ " ... ; -becomes Iron stained, wltti some fine-grained sand, wet, very dense o..,,., ~ ·r·.,:. l~. ,.f ll ... O 0. 0 o .. \l, .'"•\l,J"' • • a o • ...... , " ~ •6 0 b I o,t.,: ~~! 6 ."'.;;! 't ':. :: J> ... .,. ~ .. " " ... ' .... h• ~.,. ,::,~ " .. t:iZ" i,,0 " o' •o :,o 'i.' • ~ ,0 <> a I() ·~ . 1 • .:;"~ <>o.oo.,.o<> 7 I .u"': ! ~ . " "' ~;,;, ... ; • '!a .. ' .. •o D,I <> ~ " ~ . " : ~' ~·t-;: ~: :'i\,;,, q o~· 1 ,}~"•'" •• "'I r t'll-q' s:, 8 o.,•,l'"~ (} . ·,:,'; •. c..l ·"· .o~ * Test boring was terminated at 39 feet on June 14, 2007. ' Groundwater seepage was encountered at 25 feet during drilling. BORING LOG GEOTECH 207 -219 Main Avenue South Renton, Washington CONSULTANTS, INC. Job Date: 07190 Jul 2007 Logged by: Plate: ZJM ;P 3 35 5 22 10 14 15 51 20 25 25 63 30 50 35 47 40 BORING 2 Description Brown SANO and gravel, medium-to coarse-grained, very moist, medium-dense -with larger gravels -becomes very dense -becomes fine-to coarse-grained • Test boring was terminated at 39 feet on June 14, 2007. • Groundwater seepage was encountered at 20 feet during drilling. GEOTECH CONSULTANTS, INC. Job BORING LOG 207 -219 Main Avenue South Renton, Washington Date: Logged by: Plate: 07190 Jul 2007 ZJM 4 L L... L... L.. 5 --.... .... .... 1 0 '-- --.... .... 15 '----- 1-, 20 .__ L ... .... ... 25 '--.. .!- .... L.. L.. 30 '-- .... .... .... .... 35 '-- I- L... .... L.. 40 '-- 3 17 8 23 51 26 48 52 68 79/11 • FILL BORING 3 Description Asphalt over 5/8" minus crushed rock --------·----------Brown SAND, fne-to medium-grained, very moist, loose ·srown SAND and grave!, medium-to coarse-grained, very moist, medium-dense -beoomes loose -becomes medium-dense -becomes dense • Test boring was terminated at 39 feet on June 14, 2007. • Groundwater seepage was encountered at 26 feet during drilling. GEOTECH CONSULTANTS, INC. BORING LOG 207 -219 Main Avenue South Renton, Washington s-SC $ Job Date: 07190 July 2007 Logged by: Plate: 5 ZJM -... ... ... 5 .... ... ... .. - 1 0 ----- 1 5 I,-... .. ... ... 20 ..._ ... --- 25 -... ... ... - JO -.. ... ... - 35 --.... ... ... 40 - BORING 4 Description 5/8" minus crushed rock FILL 3 Brown SAND, fine-to medium-grained, moist iOOse {FJ/1) 5 FILL 0 Brown SANO and gravel, fir.a-to coarse-grained. vary moist, vary loose 3 41 · glass shards 3 51 rMLl I Gray orange mottled. sandy SILT, highly plastic, very moist, soft Brown SAND and gravel, medium-to coarse.--grained, very moist, medium-dense 73/11 23 41 87/11 79 -becomes dense -becomes very dense ' Test bormg was terminated at 39 feet on June 14, 2007. ' Groundwater seepage was encountered at 24 feet during drilling. GEOTECH CONSULTANTS, JNC. Job BORING LOG 207 -219 Main Avenue South Renton, Washington Date: Logged by: Plate: C7190 July 2007 ZJM 6 5 10 15 20 25 30 35 40 BORING 5 Description Asphalt over FILL 1" minus crushed rock 4 12 Brown SAND and gravel, fine-ta coarse-grained, moist, medium-dense 42 -becomes medium-to coarse-grained, dense 40 8 27 32 -becomss dense -becomes very dense 62 • Test boring was terminated at 39 feet on June 14, 2007. • Groundwater seepage was encountered at 24 feet during drilling. ~-ii GEOTECH CONSULTANTS, INC. BORING LOG ~>,,,..f;;t;.s....,,..,!"l!!or="'=""""".,,,,,,... Job 207 -219 Main Avenue South Renton, Washington Date: Logged by: Plate: 07190 Jut 2007 ZJM 7 21 5 8 10 20 15 28 20 6 25 42 30 76 35 66 40 BORING 6 Description Brown, silty SAND with gravel, fine-to medium-grainsd, very moist, loose to medium-dense (Fill) • Test boring was terminated at 39 feet on June 14, 2007. • Groundwater seepage was encountered at 24 feet during drilling. GEOTECH CONSULTANTS, INC. Job BORING LOG 207-219 Main Avenue South Renton, Washington Date: Logged by: Plate: 8 07190 July 2007 ZJM 5 1 0 1 5 2 0 25 30 35 40 L... ... ... ... .__ -- L-.. .__ ... ----... ... ... ... ..... ... ... ... ... ,..._ ~ ~ ... ... --... L... -,__ ... ... ... L... < -- BORING 7 Description Brown SAND and gravel, fine-to medium-grained, moist medium-dense (Fil~ 13 2 I FILL -pea gravel Brown SAND "iirld gravel, medium-to coarse-grained, very moist, dense -becomes very dense ' Test boring was terminated at 39 feet on June 14, 2007. ' Groundwater seepage was encountered at 25 feet during drilling. GEOTECH CONSUL.TANI'S, INC. BORING LOG 207 -219 Main Avenue South Renton, Washington -*1 l~~·~~~ --~--..==---..-Job Date: Logged by: Plate: 07190 Jul 2007 ZJM 9 Drainage composite~ Waterproofing-...__.~ /Treated lagging Vapor retarder Non .. woven fllter fabric -------,. Washed rock or pea gravel-----b. 4" perforated PVC drain (holes turned downward) 2" PVC weep pipe at 6' centers (Pour Into footing or wall below slab) Attach weep pipe to drainage composite. Pierce waterproofing and plastic backing of drainage composite. Soldier pile Note. Refer to the report for additional considerations related to drainage and waterproofing. GEOTECH CONSULTANTS, INC. FOUNDATION DRAIN DETAIL 207 -219 Main Avenue South Renton, Washington 'Job No: 07190 I Date: July 2007 I Plate: Rll.· --,. bJLl_~ ..,, .... ~ ~ s ~ m ~ • " m • • 0 ~ • 0 m ~ § g ~ z . ' s: )> -z )> < m • en 0 C -I ::I: z 0 ::c -I ' ~ tel s::; ::I: " .. e t 0 (I]; ;t,- ,1, ,6' o·, r----- tt·~1--T-~~·-·-· I , , , ' _·:_ ;.:.... :_~t----1· I I I I I • I I tit. -1-·T·r. ------r~-1 - 1 · ' ' I , I ! I ' ' I i i i ~: r -----r~-i-1 ,, . , , , , I ru1: I I I ! j 1 ' , I I I I I ; Ir. 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LJbffiy Parle :ri " ~ 0 ~ ! <n < ~ ± ,; " -" ;f c...i.,, '9;'1,. ?<;,l_!, "'%4 N _ Renton,.-;,. communtty c~nti:-r '--' carci, Th.ea,re--(a:· ,:f ~ar River Park Cedar Aivr:F Tr,,,· -,.t/1,,, "'"'7/.f WEBE e-~!~}NITY PLAN (!' -~ Henry Mo A.qua,k; Ce1 c~a ~ .,,,.. Ir '"- • - + I "' s 9 I) ti -·· A A Mapdala€2()1.ll{looyle Term~ Pr1Yacy R~ortap1oblem :rnofl'------' LAND USE HEARING SIGN-IN SHEET Heritage Apartments LUA14-000933, CU-H, SA-H, MOD September 9, 1:00 PM PLEASE PRINT LEGIBLY ADDRESS Phone# with area code Email NAME (including City & Zip) (optional) (optional) p& N'A/ IS j\ll.45c,4,i' /,IV 45 & ?c:/7 S-5' 1;{ ,4 VE· S; J4< '1/Jl/f' -f/t,_i:,v,-/1 '1<';-j tL-h ii>cjffe_,, 1, '7l/b :i3'ER(...1Nc.:< -?us · X)l · :.JI?'(.-./vC. I ,( /,b~q-L{ 5c~e / {\? o-+ .350C.. "PcH--lc-JX -~ l Ve;,~ 4is-. 1'>,. 339;;; -, I ~rt\,_1,~k, lneitY-ctxl.e 1[t> ... '.v ' net ) ) I ~ })AJ./C Cf 0 .e _; u.cck, /ooc: _s. 2nd id-ll~A/ -~00 q qq 41'0) i,. .. h ,<-f ('~ «de, f)lY.OL, 0~ \-?~-\J ou.J f\>0-~ "£i C:::wl ~ -\\-s _ 0 .. -t '[-ZS°' :2..')J.,, ~L(L q, C}....,_l-{..4 h .. ..._\\:,'. ~ 1 y, <-tM5 Pc.~ fld--C2)w-~--- /\Ji .I j IA 1/1 ,~ /, ( eAf. //._ looJ-..S 8--H d. If-Kffl!hJ/1 f/1fovi I 01 m d2e.. c:;~, iJ J lfrttg §DCI ena1neeRs 5 Seattle u Portland '" Spokane t .I; San Diego 0) Austin ~ Irvine :g Eugene I San Francisco Anchorage TECHNICAL INFORMATION REPORT For Renton Heritage Apartments 207-219 Main Avenue South Renton, Washington Prepared for: Stricker Cato Murphy Architects, P.S. 311 First Avenue South, Suite 300 Seattle, Washington 98104 DCI Job No. 14012-0023 July 15, 2014 818 Stewart Street, Suite 1000 Seatt.a, Washington. 98101 Phone (206) 332-1900 Service Innovation Value ---- CONTENTS SECTION I -PROJECT OVERVIEW SECTION II -CONDITIONS AND REQUIREMENTS SUMMARY SECTION Ill -LEVEL I OFF-SITE ANALYSIS (:it:,; (1-i r~ion \ i. 1 '1 I' , 1 '. I· ··J ' ' I SECTION IV -FLOW CONTROL & WATER QUALITY ANALYSIS & DESIGN SECTION V -CONVEYANCE SYSTEM ANALYSIS & DESIGN SECTION VI -SPECIAL REPORTS & STUDIES SECTION VII -OTHER PERMITS SECTION VIII -CSWPPP ANALYSIS & DESIGN SECTION IX-BOND QUANTITIES, FACILITY SL'MMARIES & DECLARATION OF COVENANT SECTION X-OPERATIONS & MAINTENANCE MANUAL Renton Heritage Apartments DCI Engineers SECTION I -PROJECT OVERVIEW This report summarizes stormwater control design considerations for the construction of a six-story mixed-use building at 207-219 Main Avenue South in Renton, Washington (Figure 2). The building will include commercial space at the ground level and five additional stories of residential consisting of IO 1 residential units on a 0.68-acre site. There will be one below grade parking level with 39 parking spaces accessed from the alley and 47 additional parking spaces at 5 feet above grade level, accessed from an alley on the west side of the building. An additional 17 at grade parking spaces will be accessed from the alley. The site was previously occupied by a gas station with a service building on the north half. The south half of the site was previously a parking lot. All above-grade improvements have been demolished. The site is nearly level. The property's stormwater runoff is conveyed into catch basins that are located on the east side of the prope1ty and also conveyed into the alley on the west side of the property where it collects into a gutter system that runs east along S 2nd St and into a catch basin on the southwest corner of the intersection on S 2°ct St and Main Ave South. The building will be constructed on a mat foundation. The parking garage and foundation will be excavated using shoring as recommended by the geotechnical report. The west and east sections of the parking garage will be excavated using a 1.5: I (H: V) benching and the north and south sections of the building will be excavated using a 2: I (H:V) benching. The excavation depth will be around -13 feet deep at the maximum depth on the north side. The minimum depth will be around -9 feet deep at the south side of the building. (Figure 3 ). A July 2007 geotechnical report by Geotech Consultants, Inc. (see Section VI) identifies the predominant soil on the site as medium-dense alluvial (water deposited) sand and gravels, overlain by three feet of fill and 15 feet of fill where gas tanks were previously located. Groundwater was encountered at depths of 20-26 feet. The site is substantially impervious and there will be minimal change in flow characteristics of the site with the proposed construction. Renton Heritage Apartments DCI Engineers f1e:,u,tc.; ,,, KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MA)IUAL TECHNICAL INFORMATION REPORT (TIR) WORKSHEET 1-~art-; P~OJECT OWNER AND I PROJECT ENGINEER ' Project Owner C.os.,.os f)r,~i:tol'liuw( (.D..,PlrtJ / Phone ( ql~) 4S"/ • fi/gg' , fxT /?/) Address \\ 1<i 1 Ng fIKsT sr 5Uffc J!D1) S,(LLf~u" , w 1r c:izc,"s- Project Engineer ________ _ Company DL l I:~ t,.pJi-ll"R ~ Phone Part 3 TYPE OF PERMIT APPLICATION 0 Landuse Services Subdivison / Short Subd. / UPD ~ B~g..Se.c(ices iMlf)t~~ I SFR 'Ci Clearing and Grading 0 Right-of-Way Use 0 other Part5 PLAN AND REPORT INFORMATION Technical Information Report i Type of Drainage Review ~/ Targeted 1 (circle): ge Site Date (include revision dates): Date of Final: I Part 6 ADJUSTMENT APPROVALS I I --·- Part 2 PROJECT LOCATION AND . . ····~ DESCRIPTION -------·-------, Project Name \J. ~R1T lru-G AP}.~ (l,{r;, .. rts DDES Permit# --------- [ Location Township 2? fJ I Range S (; Section Ir I Site Address '2.C>'I • 2\"I V. ~w S\IJE:tJtl'" I Qww q..) i w .1r " f c> !.r Part 4 .OTHER REVIEWS AND PERMITS 0 DFWHPA 0 COE404 0 DOE Dam Safety 0 FEMA Floodplain 0 COE Wetlands 0 Other --- 0 Shoreline Management 0 Structural RockeryNault/~- 0 ESA Section 7 I Site Improvement Plan (Engr. Plans) I Type (circle one): ~ I Modified I II Site Date (include revision dates): Date of Final: ! Type (circle one): Standard / Complex / Preapplication / Experimental/ Blanket Description: (include conditions in TIR Section 2) Date of A roval: c...:::.==c'-"!Ct'..'..C'...:~--------------------·-·-·· _J 2009 Surface Water Design Manual 1 119/2009 'f°lt,uRi' 1-2 KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL TECHNICAL INFORMATION REPORT (TIR) WORKSHEET lPart 7 MONITORING REQUIREMENTS Monitoring Required: Yes / No Describe:------------- Start Date: Completion Date: . Part 8 SITE COMMUNITY AND DRAINAGE BASIN Community Plan: ____________ _ Special District Overlays:----------------------- Drainage Basin: (, Ei [) ~ R ~ 1 1/G=l'L Stormwater Requirements: ?E" J.k;. ro.:.; C.6-.J t Ro L Part 9 ONSITE AND ADJACENT SENSITIVE AREAS .. 0 River/Stream ________ _ 0 Steep Slope ________ _ 0 Lake 0 Erosion Hazard ______ _ 0 Wetlands __________ _ 0 Landslide Hazard ______ _ D Closed Depression _______ _ 0 Coal Mine Hazard -------D Floodplain _________ _ ~ Seismic Hazard ______ _ D Other ___________ _ 0 Habitat Protection ______ _ ~ 'tl/ft. Part 1 0 SOI LS Soil Type Slopes t,A1: Dl:VM UENS1t, L fli l:L ':> \Ti: Erosion Potential LOW AU.V'll f\ I. ( \No,-1-r• Otros-W) s~ I) A!J.I) &~•s ' 0 High Groundwater Table (within 5 feet) 0 Other _________ _ D Additional Sheets Attached 2009 Surface Water Design Manual 2 ~ Sole Source Aquifer 0 Seeps/Springs 1/9/2009 fl f71Ji.'i' 1. t KING COUNTY, WASIIINGTON, SURFACE WATER DESIGN MANUAL TECHNICAL INFORMATION REPORT (TIR) WORKSHEET ::rt-F-:-:-E:-~-E_I_N_A_G_E_D_E_S_IG_N_L_IM_IT_A_T_io_N_s ___ L_IM-I-TA_T_I_O_N_/_Sl·T-E-CO-NS_T_RA_IN-T====-----1 D Core 2 -Offsite Analysis D Sensitive/Critical Areas D SEPA I ~ Other 'zo,ull: 'I-~Qol fl:!! ~or~~ I D k?..~"' [El Additional Sheets Attached ~··--------- I Part 12 TIR SUMMARY SHEET _(f>rovide one TIR Summary Sheet per Threshold Discharge.AJea) -· Threshold Discharge Area: i . (name or description) . ---------~O\Ec..1 S\1i:t Core Requirements (all 8 apply) ·---- ___ ._Discharge at Natural Location Number of Natural Discharge Locations: Offsite Analysis Level:· G)t 2 / 3 dated: Flow Control Level: ,Q 2 / 3 or Exemption Number (incl. facility summarv sheet) Small Site MPs Conveyance System Spill containment located at: . ·--- Erosion and Sediment Control ESC Site Supervisor: T~i) Contact Phone: After Hours Phone: Maintenance and Operation Responsibility: ~ Public __ If Private,.Maintenance Log Required: Yes / No Financial Guarantees and Provided: Yes / No Liability . Water Quality Type: B~~ Sens. Lake / Enhanced Basicm / Bog (include facility summary sheet) orCExemptio . IB L Landsca2e Management Plan: Yes / /NO) i Special Requirements (as aoolicable) Area Specific Drainage Type: CDA / SDO / MOP/ BP/ LMP / Shared Fae. / None Reauirements Name: I>,-~v. 1 f(E flJ).,J (.OtJTI\O L <Ji' >,.w i) I.~ I) l\,~1, A ---- Floodplain/Floodway Delineation Type: Major / Minor / Exemption / ~ i 100-year Base Flood Elevation (or range): Datum: Flood Protection Facilities Describe: ~o~V: Source Control Describe landuse: (comm./industrial landuse) Describe any structural controls: 2009 Surface Water Design Manual 1/9/2009 3 fJ ~~, (.If KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL TECHNICAL INFORMATION REPORT (TIR) WORKSHEET ------;co'"il~C"_o_n_"t_r_o;-1 ------------;H"'ig--;h---us-e--cS;cic-te-: --;Y7e_s_/,_@r,-,o_---------------- Treatment BMP: -------------- Maintenance Agreement: Yes / No with whom? Other Drainage Structures Describe: ~oDf i)Rt,.~<; ~ Part 13 EROSION AND SEDIMENT CONTROL REQUIREMENTS MINIMUM ESC REQUIREMENTS MINIMUM ESC REQUIREMENTS DURING CONSTRUCTION AFTER CONSTRUCTION D Clearing Limits \B' Stabilize Exposed Surfaces l8I Cover Measures 8J Remove and Restore Temporary ESC Facilities ~ Perimeter Protection 2iJ Clean and Remove All Silt and Debris, Ensure 5,;I Traffic Area Stabilization Operation of Permanent Facilities 5:il Sediment Retention D Flag Limits of SAO and open space 0 Surface Water Collection preservation areas D Other 0 Dewatering Control !iii' Dust Control D Flow Control --·-·-----"---·----·---- Part 14 STORMWATER FACILITY DESCRIPTIONS (Note: Include Facility Summarv and Sketch} f------·--· Flow Control Tvoe/Description I Water Quality Tvpe/Descriotion i D Detention I D Biofiltration D Infiltration D Wetpool D Regional Facility 0 Media Filtration D Shared Facility D Oil Control D Flow Control D Spill Control BMPs D Flow Control BMPs D Other \JO\!~ 0 Other t.)oojg 2009 Surface Water Design Manual 1/9/2009 4 1-1. 6'-'"i:: , . , KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL TECHNICAL INFORMATION REPORT (TIR) WORKSHEET Part 15 EASEMENTSfTRACTS Part 16 STRUCTURAL ANALYSIS D Drainage Easement D Cast in Place Vault D Covenant D Retaining Wall D Native Growth Protection Covenant D Rockery > 4' High D Tract D Structural on Steep Slope D Other 0 Other Part 17 SIGNATURE OF PROFESSIONAL ENGINEER I, or a civil engineer under my supervision, have visited the site. Actual site conditions as observed were incorporated into this worksheet and the attached Technical Information Report. To the best of my knowledge the information provided here is accurate . . /t/ ~ · // . '7/;S~L/ ' Sianed/Date 2009 Surface Water Design Manual 5 l/9/2009 S 2nd ST S 3rd ST "' . ~ SITE "1 ·1 s 7th ST ~ \ --"' VICINITY MAP NOT TO SCALE I A 8 C D E F G 2 [XISfcNG 66" WAl(R UN£, P!i'OlfCI I~ Pi.ACE PROTECT IN PLACE [XISTlNG WATER LINE 3 R;.tSE EXISTING STREET LIGHT covrn TO nN1Sr1 GRADE------~ . -~INSTALL N(WHEE··s-TANOtNG-FOC·-~-7".,... INS~ALL NEW "r1R[ HYDRANT AS.StMBLY:-</' ----•• -I -I ', 4 1 l S. 2ND STREET ~· 5 ----INSTALL NEW 12· WAlf_R, ENGINEERING DETAILS PROV1DEO ON flil\/RE ?LANS , ---EX1Si1NC-$TORl.l ·~"R-AIN UNE; PROTECT IN PLAC( _ •. -:__ ---:_~ RAISE [~IS.TING H£CTRCAL VAULT LID TO FINISH GRADE ,,.,--i.----R"ASE EXISTING GOMI.I \/AULT LID TQ_fJNISH GRADE -----[(j] --~_/ /~,--/ ·_;/-::,:: ' --- ~-_-_:--:<tl j. _ ,· I --i-/ Hf/ ---t=~ -c--- R.AIS[ [XISTING GAS AP~URTINANCE LID ----=-- _j~--.-- EXISTING BUILDING, PRGT!:CT IN PLACE ~j],fi--i"i:<~ UPPER F1.00RS/ BALC:'.JNY ----- ltJSlALL N[W 16' WIDF ASPH/1.U ALLEY ----~- :.u___.=-L _ ~-'.; -·;;:., ., ifl1{ ~ iJ t:</-·t:~r·__ -0 fXISTlNG CATtf' Bl'ISIN, PROTE--CT IN PLAff, -· LL.._ L;l::__~ 1 .~ ' _ _--" ,,.-. ~ t;J_ j___.c:-. l IN5TALL CATCH BASIN INSERT (TYi') ) :· --~ ·--...._ ;, ).<-t ~,;,;;-~ f _ /~·--· ---REJSE EXISTING SID[ SE.vER LINE. SEE SEWER NOTE ~ \ ·, -· .,.-,,-' --~ INSTALL NEW TYPE I CATCH BASIN AND BUILDING c--• _-STOf/1.1 ORA.IN CONNECTlON '\ ! --_ s_.----:NSTALL NfW TYPE I CATCH BASIN \\'lTH SOLID i " I. ~ I "' ,.,,---.--, LOCKING U:J r~ f · , ',._ 1 _ ~--, INSTAL N(W flR[ HY()RANT 11ss[f.lBLY -i I ~ '!!_-'J' ____ ;__ EXISTING CURB AND GUTTER. PROTECT IN PLACE '. f I -·r 1-. -. / --·-----,---EXl?ll!_lY GAS c.l_N_~"~~OTECT !N PLACE I 1,· , _,,.;.,/ _,/ ~ '-~--~~6~~~DN~% ?~,T~tETEt[A~~GINt'~lJ.H, urnn:s------JI 1.----i-----REUSE EXISTING s1ot 'if:WER UN~ sn SEWER NOTE ~ I ---,;----EXIS"JNG 8 WARR LINE PROTECT IN '-'L/1.CE ~ j 1 ~ --=--1 -j -; -11 _..,. / ~ ----EXISTING 8 SEWER LINE PROTECT IN al/I.CE ~ 1 r ,,. -~ -EXISTING sTORf.l DRAIN LINE PROTECT IN PLAC~ _j c.l / l I :1~---~ -----fF-:-~ .-_l/ .---,,,m, "" C,R[ """'"' "'"'" ; ' L I -~ t r ! I co ' I ~--------INSTALL NEW TYP[ I C/1.TCt< BASIN win, SOLID • LOCK:NG LID 1 I 111 -: , . _. INS!A1.l NEW lYPi: I CAlCh BASIN ANO BUILDING sroRt.t DRAIN CONN[CllON 6 i I. , i I -i . . ~ g'.'.:-::c~,. f ,,, !'< ' I ~ I I ~ ·---- __,,,". ,.,.,1._; ~-'c::J-J ~ ------l-~ i----r I ~ , ~ r j r "" _ ~-1 ---INSlkl NE.II' SlRtET 'REE AND PLANTER (TYP) --RAISE EXISTING H.ECTRICAL HAND HOLE LID TO FINISH GRADE 4 ""'"'-"1 _ -L ---j /. ------INSTA'.L NEW 5" SIDE SEWER CONNECTIO~ WITH CL[ANO'J" -' -~ -INSTA,L NEW lYPE I C/1.TCH BASIN ANO BUILDING ,.,, STORf.l DRAIN CO~NECTIDt. l ~ --------INSTALL NEW TYPE I CATCH BASIN WTh SOLID i l I J .. ->----~-~ --~::~N~~~~G STREET LIGHT C0\1:R TO FINISH GR/I.OE -~ ~ ~__µ -----------J~-2_:--__ .-/------1-·· ---RAISE EXISTING LID Tel rn,1sH GRAD[ l I f-• l l i __ :-~/----~~ :::::~~ :~~G:~:~N H:;:Tll::S::~:CVA INTE~I~ TO BUILDING · I 1-_, f -.f 1----1-~ -------I w W---t:---INST/I.LL riR[ WATER UN[ I -' . -.. ----r--·-·~ : . . ==-._::-~. W-, -~,-----INST ALL COMM~RCIAL WA-ER LINE ANO RPBA ~ ....... ~. _J / i ~ G $\: /,, 1'11THIN BUILOING ' . j ! iiicc'"" ': j '.~~·J ···-~-----~ST:~,. :S-S[ROC[ '"' ,me ."·::f>'.,:---:,-..'J PRCTECT IN Pl.ACE EXISTING CCf.lMIJNICAllON clN[S ----=c::-- PROTECT IN PLACf EXISTING GAS I INF SAWCU1 EXISTING CONCRf"lF -INSTALL DOMESTIC WATER LINE WITH OCVA INTERIOR TO BUILDING --~~!5-~-,,,,- -~.,~31 ~,,-_ -::~~(-- POTENTIAL EL[CTRICAL TRANSFOR~(R, COORDINATE W!Tl-' PS£ BELOW G~AOf PARK·NG -- EXISTING BUILDING, PROTECT IN PLACE SEWER NOTE POT HOLE AND CAMERA TO 'IERlrY INVCRT [LEVA TION, LOCATION, AND CONDITION R~LINf AS DIRECTED BY ENGINEER IN ACCORDANC( \l,ril-i CHY OF RENTON SH.NOARO PER THE PLUMBING CODE BACK WATER VALVES ARE REQUIRED ON ALL $10[ SEWERS 1'11-1ERE Tu[ F!W>HD FLOOR ELEVATION IS ~OWER Tl-lAN THE El F'IA TIC'l'I Of TltE l}I[ NEXT UPSTREAM I.IANf-10'_[ RI~ ELEVA110N UPC 2009 SECTION 710.1 NOTE All N[W ANO [XISTiliG HAND HOLES & VAL V[S S'1ALL BE FURNISHED WITH NON-SKID LIDS GRAPHIC SCALE ~~~ cw:: ~- ( J}ln:n} ) 'l>Ch ~ 20 ft r UNDERGROUND SERVICE ALERT ~ • e -Ulg .J U a:~~ ~ !::a:, :, w~; § i-c w~5 lg C i=~ -~o:: tl'J :i::: go 1- 1111 ~ i ! i~ c~g ~ 5 w;;;~ ~ U I'! I i I I ' I I ! -- ~ ! ls ' ~ ~ ~ . •• '- " ~ ' 1: 11 ' ;: , [ .f ~ ~ i t & l l w UJ (.!) > <( <( I-en z -1--a::: z <( <t WUJL;;: :::C: L c,0 z I-0 zo::1-~ Q<(enW I-CLO a:: <(z Z N w a::: en ~ ~ • - Srl£ET mu SITE UTILITY PLAN ® ONE-CALL NUf.lBER (800)424-5555 °'"' '° § rnST,'° m METER POOffCT " PC.CE --~ I ~ -°"' '" '"'""' om I C 2 • Q I " ' BEFORE "OU DIG ~ "10:t•O .,,., 1<. 2014 -<26pm ,t,emon~er O\Oc-C.,,1\2014\14012-002-1-~e"lon-Hec,luee-A,1\o~g\1002,-"L'ld~~ .,~o,I Nome CiDu SECTION 17, TOWNSHIP 23 NORTf-1, RAN';E 05 EAST, W.M -~ Soil Map-King County Area, Wash ington ~ ~ 1i1 ~ ,.. El e 559300 559400 559500 559600 559700 5599:Xl 559'l00 560000 -~ .• .I ••. ------i 47" NJ"N 47" N3'N ~ ~ ~ !!l "' 8 ~ 8 ~ -,1 ; :I ',, 1111 I II ; --, G' C ~ -'!I . 'lWIN ' ,u '...:..~-';S" rn ··--I -; ,_.. i lill . ·-. CII • ~ i I ..t • "' - ~ i ~ "' ~ "' I 47" 28' 38" N ------r I I I I 47" 28' 38" N 559300 559400 559500 559600 559700 559000 559'l00 560000 560100 560200 560300 560400 ~ ~ ~ Map Scale: 1:5,500 if pirm:1 on A landscape (11" X 8.5") sheet 1i1 ~ Men,, ;:: El N 0 50 100 200 300 El A Feel 0 250 500 1000 1500 Map projection: Weh Men:::atIY o:me-roordnates: WGS84 Edge oo;: I.JT7'1 Zone IQ',/ WGS84 U~l),\ Natural Reso urces Web Soil Survey 6/25/20 14 ---.. Conservation S ervice National Cooperative Soi l Survey Page 1 of 3 US DA .r Soil Map-Ki ng Cou nty Area. Washi ngton MAP LEGEND MAP INFORMATION Area of Interest (AOI) D Area o f Interest (AOI) Soils _J ..-.,,,, • Soil Map Unit Polygons Soil Map Unit Lines S oi l Map Unit Poin ts Special Point Feat ures ~ Blowout ~ Borrow Pit • Clay Spot () Closed Dep ressio n X Gra vel P it Gravelly S po t 0 Landfill A. Lava Flow a Marsh or swamp ~ Mine or Quarry 0 Miscellaneo us Water 0 Perennial Wa ter V Rock O utcrop + Saline Spot Sandy Spot @ Severely Eroded Spot 0 S inkh ole ~ Slide or S lip ti Sod ic Spot Natural Resources erv -ervi, ~ Sp oil Area ~ Ston y Spo t m Ve ry Stony S pot \I' Wet Spot 1'::. Oth er ... S pecia l Li n e Features Wate r Fe atures Strea ms a nd Canals Trans portation +++ Rails ~ Interstate Highways -US Route s Major Ro ads Local Ro ad s Background • Aerial P hotography Web Soi l Survey ••-·•---1 co -----~ve S ·· ~ ey The soi l surveys that compri se your AO I were mapped at 1 :24 ,000 . i.Wami.ng~~i l Map may not be va lid at th is sca le . Enla rgement of maps beyond the sca le of ma pping can cause . misunderstand ing of the detail of mapping and accuracy of soi l line l placement. The maps do not show the small areas of contrast ing soi ls that cou ld have been shown at a more detailed scale. . ---- Please re ly on the bar sca le on each map sheet for map measurements. Source of Map: Natural Resources Conservati on Service Web Soil Survey URL: http://web soilsurvey.nrcs .usda.gov Coordinate Sy stem: Web Mercator (EPSG:3857) Maps from the Web Soil Su rvey are based on the Web Mercator proj ection, wh ich preserves direction and shape but distorts distance and a rea. A projection that p reserves area , such as the A lbe rs equa l-area con i c projecti on, shou ld be used if more accurate ca lc ulations of distance or area are requ ired . Th is product is generated from the USD A -NRCS certifi ed data as of the vers ion date(s) listed be low. Soil Survey Area: Survey Area Data: King County Area, Washi ngton Version 8 , Dec 10 , 20 13 Soil map units are labeled (as spa ce a ll ows)for map sca les 1 :50 ,000 o r larger. Date(s) ae rial images were photographed: Aug 31 , 20 13-0ct 6 , 2013 T he orthophoto or other base map on whi ch the so il lines were compi led and dig it ized probably diffe rs from the background imagery d isp layed on th ese maps. As a result , some minor sh ifting of map unit boundaries may be eviden t. 6/25/20 14 n -ge 2 -·" ~ ~ C .,., CV ~ ~ Soil Map--King County Area, Washington Map Unit Legend Map Unit Symbol AkF ' :AmC 1 BeD :------- Rh Ur w Totals for Area of Interest USDA Natural Resources ,.... -Conservation Service I King County Area, Washington (WA633) Map Unit Name Alderwood and Kitsap soils, very steep I Arents, Alderwood material, 6 to , 15 percent s!opes Beausite gravelly sandy loam, 15 to 30 percent slopes Rive!'W'ash Urban land Water Acres inAOI Web Soil Survey National Cooperative Soil Survey 1.3 7.9 0.1 0.2 129.B 4.0 143.4 I Percent of AOI 0.9% 5.5% 0.1% 0.2% 90.5% I 2.8%: ··---' 100.0% 6/25/2014 Page 3 of3 SECTION II -CONDITIONS AND REQUIREMENTS SUMMARY This project is subject to full drainage review under the 2009 King County Surface Water Design Manual (KCSWDM) and the 2009 City of Renton Addendum to the 2009 KCSWDM. The site lies in a Peak Rate Flow Control Standard Area as delineated by the City of Renton. The following is a summary of how the project will address each of the core stormwater requirements identified in the KCSWDM. Core Requirement# 1 -Discharge at the Natural Location: A series of catch basins on Main Avenue South and catch basins at the northeast corner of the site provide a natural discharge location for stormwater runoff. Storm water runoff generated on the site currently appears to sheet t1ow toward the north and east section of the lot, where it is collected in multiple catch basins and is piped to a 12" storm sewer in Main A venue South. The proposed development will preserve this drainage pattern to the maximum extent feasible. Core Requirement# 2 -Off-site analysis: See section III, "Level I Downstream Analysis". Core Requirement # 3 -Flow Control: This project is in a Peak Rate Flow Control Standard Area and is required to release stormwater at rates not exceeding 2-, 10-, and JOO-year return periods for existing conditions. Because the site is nearly 100% impervious, this project will not increase runoff over existing rates. Consequently, no t1ow control measures are required. See also Section IV, "Drainage Analysis". Core Requirement# 4 -Conveyance System: See Section V, "Conveyance System Analysis & Design". Core Requirement# 5 -Erosion and Sediment Control: See Section VIII, "ESC Analysis and Design". Core Requirement# 6 -Maintenance and Operations: Maintenance and operation of the on-site drainage system is the responsibility of the property owner. See Section X, "Operations and Maintenance Manual". Core Requirement# 7 -Financial Guarantees and Liability: Per RMC 4-6-0301 the project will require a bond for all stormwater conveyance systems installed on the site prior to the City of Renton issuing a permit. This will be presented to the City once final construction plans are approved and a utility contractor has been selected. Core Requirement# 8 -Water quality: This project qualifies for Exemption #I b on the 2009 City of Renton Addendum to the KCSWDM. Less than 5,000 sq. ft. of new PGIS plus replaced PGIS will be created with the redevelopment project. Repaving of the alley will consist of approximately 4120 sq. ft. of replaced PGIS for the project. Renton Heritage Apartments DCI Engineers Special Requirement # 1 -Other Adopted Area-Specific Requirements: There are no known area-specific requirements applicable to this project, other than the Peak Rate Flow Control Standard Area designation. Special Requirement # 2 -Flood Hazard Area Delineation: The project site is subject to no identified flood hazards identified in the Revised FEMA Preliminary DFIRM Nov. 2010 (Figure 6 in Section Ill). Special Requirement# 3 -Flood Protection Facilities: There are no known flood protection facilities impacted by this project. Special Requirement # 4 -Source Controls: When the Renton Heritage Apartment building is in operation following construction, it is not expected to generate significant sources of pollution. Special Requirement# 5 -Oil Control: Oil control facilities are not required per KCSWDM 1.3.5 because the proposed facility does not meet the definition of a "high use site''. Special Requirement# 6 -Aquifer Protection Area: The project is located within Zone I of the Aquifer Protection Area. None of the restricted drainage facilities listed in the 2009 City of Renton Addendum to the KCSWDM are proposed on the site. Renton Heritage Apartments DC! Engineers SECTION III -LEVEL 1 OFF-SITE ANALYSIS DCI staff have obtained GIS stormwater records from the City of Renton, and have walked the stormwater conveyance route from the project site to the point at which the conveyance discharges to the Cedar River approximately 700 feet to the east. A map of the downstream path, excerpted from the city's GIS mapping, is provided as Figure 5 following this narrative. All stormwater runoff generated on the project site drains to the public rights-of-way on Main Avenue South, S 2nd Street and the alley on the west side of the site. The alley drains north to the 2nd Street gutter, and 2nd Street drains east toward an inlet at the southwest corner of Main Avenue. This inlet is connected to a 12-inch storm sewer draining north on Main Avenue. The Main A venue storm system turns east at a Type 2 catch basin in 2"d Street and drains approximately 300 feet east to Mill Street, where it passes through catch basins at the southwest and southeast corners of the intersection. The flow continues approximately 200 feet east through a parking lot to a Type 2 catch basin near the 200 Mill Building, where it turns to the northeast 200 feet through a landscaped courtyard and discharges through a rubber flap gate on the bank of the Cedar River approximately 75 feet southeast of the public library building, which straddles the river. The entire 700-foot run of the conveyance route appears to be constructed of 12-inch concrete pipe. Renton Heritage Apartments DCI Engineers ___ r 11,Uft C !, 1/4 MILE DOWNSTREAM FLOWPATH -CITY OF RENTON I 1 1 0 11200 0 100 2 0 0 Feet WGS _ 1984 _Web_ Mercator_ Auxiliary_ Sphere City of R.ento fl {~:,. Finance & IT Division Parcel s Network Structures ICJ 1n1e1 @ Manhole D Utility Vault C Un known Structure ® Control Structure • Pump Station • Discharge Poi nt ,r W:atPr 011:alitv Information Technology-GIS RentonMapSu pport@Rentonwa.gov 6/27/2014 P ipe Vau t Wetand Culve rt Open D rains Faci lity Outline Fence 0 Stormwater Pon d s • Faci lity Transfe r T his map is a user generated st.Jhc 0t1tr.tJ I from an 1n1ems: mappng site .1ra 1s for re ference o n y Data layers tha t appear or1 Un~ ma;i rr-a y or nay not be ac:r:u r;ita. current :)t o the'Vl.isP. mlirtble THIS MAP IS NOT TO BE USED FOR NAVIGATION SECTION IV -FLOW CONTROL & WATER QUALITY ANALYSIS & DESIGN Part A -Existing Site Hydrology The 0.68 acre project site comprises of four parcels at the southwest corner of the intersection of S. 2"d Street and Main Avenue South. Aerial photographs show the site has had nearly 100% impervious cover since at least 1990. See Figure 7 at the end of this section. Buildings adjacent to the south boundary, an off-site conveyance system on Main Avenue South and the alley that runs along the western boundary of the site handle the stormwater runoff on the site. Runoff generated on-site sheet flows toward the adjacent streets. There is one existing inlet on site that is located near the eastern boundary where it is piped to the 12" storm sewer main on Main A venue South. Part B -Developed Site Hydrology This project is in a Peak Rate Flow Control Standard Area and is required to provide Level I (match existing conditions) flow control in accordance with KCSWDM and the 2009 City of Renton Addendum. The project will be constructed on two levels. A 39 space parking garage will be constructed 5 feet below grade and an additional 17 parking spaces will be constructed at grade level. A second parking level 5 feet above ground will hold an additional 46 parking spaces. There will be three parking entrances located at the alley which consist of a parking entrance to the below grade garage that will be located at the southwest end of the project site and a parking entrance for the above ground parking located near the northeast end of the building. The at-grade parking will be accessed from the alley. The first main floor of the building will be at-grade and the total building footprint will occupy approximately 89% of the site. The remaining 11 % of the site will consist of impervious paved surfaces such as sidewalks, access ramps and paved vehicle entry as well as some landscaping. All stormwater runoff managed on the site will be tightlined to the existing public storm system at the northeast corner of the site. (See Figure 3 in Section L) Part C -Performance Standards This project is in a Peak Rate Flow Control Standard Area and is required to release stormwater at rates not exceeding the 2-, 10-, and JOO-year return periods based on existing conditions. Because the site is already I 00% impervious, this project will not increase runoff over existing rates. Consequently, no flow control measures are required. Part D -Flow Control System As explained in Part C above, flow control facilities are not proposed for this project. Renton Heritage Apartments DCI Engineers Part E-Water Quality System This project qualifies for Exemption #lb on the 2009 City of Renton Addendum lo the KCSWDM. The storm water runoff to be managed by this project will be generated by non-polluting surfaces. Consequently, no water quality treatment is proposed. Renton Heritage Apartments DCI Engineers 2012 Impervious Surface Coverage Notes 'I 0 I I 64 0 32 WGS 1984_Web Mercator Aux1l1a ry Sphe re Finance & IT Di visio n 64 Feet Legend Addresses P arcels lnfonnatlon Technology -GIS RentonMapSupport@Rentonwa .gov 7/14/20 14 Tr. s map 1s a user generated static output from an !rtter,et map;:11ng site arid s for refe~ence only Dala c1ycrs that a;1pear on this map mayo· rray not be accu rate t:ur~en'.. or :i:t'erwise ·el i.ible TH IS MAP IS NOT TO BE USED FOR NAVI GATIO N SECTION V -CONVEYANCE SYSTEM ANALYSIS & DESIGN All conveyance pipes for this project will be smooth-interior 8-inch PVC or HOPE. There will be roof drains tightlincd on the eastern side of the building conveyed to the 12" concrete storm sewer main on Main A venue South. Given the shallow depth of the storm sewer on Main Avenue South, we have provided three storm drainage connections for the plumbing contractor to tie into. Three curb inlet Type I catch basins will be installed at the western flow line on Main Avenue South and routed to the existing 12" storm sewer main near the centerline of Main Avenue South. The inlet catch basins will connect to three Type I catch basins on the 12" storm sewer main. (See Figure 3 in Section I) The KCRTS analysis determined that the peak unmitigated runoff from the entire site under developed conditions for a 100 year event will be 0.321 cfs. The conveyance analysis in Figure 8.1 at the end of this section demonstrates that an 8-inch pipe at 0.5% slope has a capacity of 0.987 cfs. No single pipe in the proposed onsite system will be laid that flat or carry the flow from the entire site. Consequently, we conclude that the onsite conveyance system is adequately sized for this project. See figure 8 for KCRTS output. There are no known downstream conveyance issues that were observed during the offsitc analysis described in Section III. Existing impervious coverage will remain the same with the proposed development. Flow conditions will be matched to existing conditions and should not impact the City of Renton' s storm water collection system. Renton Heritage Apartments DCI Engineers TARGET.txt KCRTS Program ... File Directory: C:\KC_SWDM\KC_DATA\ [CJ CREATE a new Time series ST 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.68 PREDEV. tsf T 1.00000 T 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.000000 Till Forest 0.000000 Till Pasture 0.000000 Till Grass 0.000000 outwash Forest 0.000000 Outwash Pasture 0.000000 outwash Grass 0.000000 Wetland 0.000000 Impervious [T] Enter the Analysis TOOLS Module [P] compute PEAKS and Flow Frequencies predev.tsf PREDEV.pks [R] RETURN to Previous Menu [X] exit KCRTS Program Flow Frequency Analysis Time series File:predev.tsf Project Location:Sea-Tac ---Annual Peak Flow Rates--- Rank Time of Peak -----Flow Frequency Analysis------- Flow Rate (CFS) 0.165 0.145 0. 201 0.169 0. 201 0.176 0. 247 0.321 computed Peaks 7 8 3 6 4 5 2 1 2/09/01 1/05/02 12/08/02 8/26/04 10/28/04 1/18/06 10/26/06 1/09/08 2:00 16:00 18:00 2:00 16:00 16:00 0:00 6:00 --Peaks Rank Return Prob (CFS) Period 0. 321 1 100.00 0.247 2 25.00 0.201 3 10.00 0. 201 4 5. 00 0.176 5 3.00 0.169 6 2.00 0.165 7 1.30 0.145 8 1.10 0.296 50.00 Page 1 0.990 0.960 0.900 0.800 0.667 0. 500 0. 231 0.091 0.980 Results· Flow, q 0.9865 ,v, Velocity, v ' 2.9814ifllsec t2 ·' ' m I mm I tt I Inches I ,, et units: Velocity head, h.,, 0.1381 ft V 1ipe diameter, do 8 pnches vi Flow area 0.3309 ft"2 V, 1anning roughness, n 1 10.012 Wetted perimeter 1.6654 ft V 1ressure slope (possibly? equal to pipe slope), So 1.005 I rise/run [ v Hydraulic radius 0.1987 ft V 'ercent of (or ratio to) full depth (100°/o or 1 if flowing full)lso 1% ~ Top width, T 0.4000 ft V Froude number, F 0.58 Shear stress (tractive force), tau 0.1873 psf V -- r-- !:' ~ 7) >' ~: ~ "' ~ 10 ... i: .,. ("' sr, 11\ oO • - SECTION VI -SPECIAL REPORTS & STUDIES Renton Heritage Apartments DCI Engineers GEOTECHNICAL ENGINEERING STUDY Proposed Mixed-Use Building 207-219 Main Avenue South Renfon, Washington This report presents the findings and recommendations of our geotechnical engineering study for the site of the proposed mixed-use building to be located in Renton. We were provided with site plans and a topographic map. TSA Architects developed these plans, which are dated March 8, 2007. The topographic map shows the buildings and structures on and near the subject site, 2-foot contour intervals have also been mapped, and the relationship between the property and the intersecting streets, Main Avenue South and South 2nd Street are also shown. Based on these plans, we understand that the building will consist of 5 stories of residential apartments over a ground-level parking and retail area and one level of below ground parking. The project will cover the majority of the site and we anticipate cuts on the order of 10 to 12 feet. If the scope of the pro1ect changes from what we have described above, we should be provided with revised plans in order to determine if modifications to the recommendations and conclusions of this repor1 are warranted. SITE CONDITIONS SURFACE The Vicinity Map, Plate 1, illustrates the general location of the site. The property is rectangular in shape and consists of four lots at the southwest comer of Main Avenue South and South 2nd Street in Renton. The northern half of the site, at one time a gas station, is still occupied by the pump canopy and the shop building. The gas tanks on the southern portion of the northern parcel were removed in the past Currently, the building is occupied by a coffee shop and the southern half of the site is undeveloped and being used as a parking lot. The site is flat and the northern half is paved while the southern half is gravel. An 11-foot-wide alley bounds the site to the west and South 2nd Street and Main Avenue South bounds the site to the north and east. On the western side of the alley are three CMU office buildings. The northernmost building 1s a tall one-story, is located approximately 11 feet from the site, and has a finished floor elevation several feet below the alley grade. The central building ·1s located approximately 25 feet from the site and is one story tall. The southern building is two stories over a basement that has a finished floor approximately 4 to 5 feet below the alley grade. A tall one-story CMU building sits on the common property line to the south. Its finished floor elevation is near the existing site grade. Several large cracks are visible on the north-facing wall of this building, and it appears that the eastern end of the building has settled severely relative to its western end. SUBSURFACE The subsurface conditions were explored by drilling seven borings at the approximate locations shown on the Site Exploration Plan, Plate 2. Our exploration program was based on the proposed GEOTECH CONSULTANTS, INC. N & C Investments, LLC. July 18, 2007 JN 07190 Page 2 construction, anticipated subsurface conditions and those encountered during exploration, and the scope of work outlined in our proposal. The seven borings were drilled on June 15 and 16, 2007 using a truck-mounted, hollow-stem auger drill. Samples were taken at 2.5-to 5-foot intervals with a standard penetration sampler. This split- spoon sampler, which has a 2-inch outside diameter, is driven into lhe soil with a 140-pound hammer falling 30 inches. The number of blows required to advance tho sampler a given distance is an indication of the soil density or consistency. A geotechnica/ engineer from our staff observed the drilling process, logged the test borings, and obtained representative samples of the soii encountered. The Test Boring Logs are attached as Plates 3 through 10. Soil Conditions In all seven oi our borings we observed fill soils overlying loose to medium-dense, alluvial (water deposited) sand and gravels. The depth at which the native sand and gravels became dense varied across the site but typically was from approximately 20 to 25 feet below the existing grade except in boring B-5, near the northwesl corner of the site, where dense soil was not encountered until 32 feet. The maximum explored depth of our borings was 39 feet. Typically the fill soil on the site was up to 3 feet thick, except in boring B-7, drilled near the center of the northern ha If of the property where the previous gas station tanks were removed, here we encountered approximately 15 feet of fill. Large gravels and cobbles were common to all of our borings. No obstructions were revealed by our explorations. However, debris, buried utilities, and old foundation and slab elements are commonly encountered on sites that have had previous development. Groundwater Conditions Groundwa1er seepage was observed at a depth oi 20 to 26 feet. The borings were left open for only a shor1 time period. Therefore, the seepage levels on the logs represent the location of transient water seepage and may not indicate the static groundwater level. Groundwater levels encountered during drilling can be deceptive, because seepage into !he boring can be blocked or slowed by the auger itself. It should be noted that groundwater levels vary seasonally with rainfall and other factors. We anticipate that groundwater could be found in more permeable soil layers and between the near-surface weathered soil and the underlying denser soil. The stratification lines on \he logs represent the approximate boundaries between soil types at the exploration locations. The actual transition between soil types may be gradual, and subsurface conditions can vary between exploration locations. The logs provide specific subsurface information only at the locations tested. If a transition in soil type occurred between samples in the borings, the depth of the transitior: was interpreted The relative densities and moisture descriptions indicated on the boring logs are interpretive descriptions based on the conditions observed during drilling. GEOTECH CONSULTANTS, INC. N & C Investments, LLC. July 18, 2007 GENERAL CONCLUSIONS AND RECOMMENDATIONS JN 07190 Page 3 THIS SECTION CONTAINS A SUMMARY OF OUR STUDY AND FINDINGS FOR THE PURPOSES OF A GENERAL OVERVIEW ONLY. MORE SPECIFIC RECOMMENDATIONS AND CONCLUSIONS ARE CONTAINED IN THE REMAINDER OF THIS REPORT ANY PARTY REL YING ON THIS REPORT SHOULD READ THE ENTIRE DOCUMENT The site is underlain by loose to medium-dense, alluvial (water deposited) sand and gravel. The soil became dense at 20 to 25 feet below 1he existing grade except the northwest corner where dense soil was encountered near 32 feet The loose soils are compressible under the anticipated building loads and would be potentially liquefiable below the water table. Due to the size of the proposed structure, we recommend that the proposed building be supported on deep foundations embedded into the dense to very dense, native soils. Due le the presence of potentially caving near-surface soils and groundwater, it appears thal augercast piers are the most suitable deep foundation option. We understand that the proposed building will have an underground garage tor parking. This will require large cuts to be made close to the property line. As mentioned above the upper soils are loose and prone to caving; therefore, cuts in this type of sand and gravel should be limited to an inclination of 1.5:1 (Horizontal:Vertical). If these excavation inclinations cannot be maintained within the site boundaries, an easement could be sought from the adjacent property owners. If easements cannot be obtained or if they are not feasible then a temporary shoring system will have to be designed. Based on the current plans, it appears that shoring will be necessary along each sicie of the excavation. The adjoining southern building was constructed on conventional, shallow foundations and has already experienced severe post-construction settlement. Prior to beginning excavation the northern wall of this building will need to be underpinned to avoid settlement due to the adjacent proposed excavation. Based on our experience in the vicinity, we recommend that this building be underpinned by using small-diameter, driven pipe-piies. The upper soils are prone to caving a~d the presence of large cobbles and boulders makes the installation of soldier piles with lean-mix cement very difficult and unpredictable. Therefore, the drilled shoring piles are no! the recommended underpinning system for the southern adjacent building. Soldier piles can, however, be used as temporary shoring for the excavation. The minimum underpinning pile length will be dependent on the driving refusal of the piles, but the piles should be embedded into the dense sand and gravels below the lowest excavation elevation to ensure that no loads from the neighboring building are transmitted to this project's shoring or permanent below-grade walls. GEOTECH CONSULTANTS, INC. N & C investments, LL C. July 18, 2007 JN 07190 Page 4 Slabs-on-grade floors may also experience noticeable differential settlemen1 relative to the foundations. If some settlement is acceptable a slab-on-grade couid be used for the garage floors. This slab should be reinforced with steel bars to limit the potential for excess cracking when settlement occurs. A minimum reinforcement of No. 4 rebar placed on 18-inch centers each way in the slab is typically sufficient. Wherever possible the slab should be isolated from the pier- supporied walls and columns. Ar. exception to this is where interior and exterior slabs and walk ups lead to doorways. At these locations, the slab's reinforcement should be tied to the pier- supported foundations. This lessens the chance !hat a sharp downset {i.e., trip hazard) will form at the door threshold. The adjacent structures are likely suppor1ed on conventional foundations that bear on compressible soils. As a result, it is likely that they have undergone excessive settlement already. There is always some risk associated with demolition and foundation construction near structures such as this. It is imperative that unshared excavations do not extend below a 2:1 (Horizontal:Vertical) imaginary bearing zone sloping downward from existing footings. Contractors worl<ing on the demolition and construction of the building must be cautioned to avoid strong ground vibrations, which could cause additional settlement in the neighboring foundations. During demolition, strong pounding on the ground with the excavator, which is often used to break up debris and concrete, should not occur. Large equipment and vibratory compactors should not be used close to the south property line. Additionally, in order to protect yourselves from unsubstantiated damage claims from the adjacent owners, 1.) the existing condition of the foundation should be documented before star1ing demolition. and 2) the footings should be monitored for vertical movement during the demolition, excavation, and construction process These are common recommendations for projects located close to existing structures '.hat may bear on loose soil and have already experienced excessive settlement. We can provide additional recommendations for documentation and monitoring of the adjacent structures, if desired. Storm detention/reteniion facilities and other utilities are often installed below, or near, structures. The walls of storm vaulls must be designed as either cantilever or restrained retaining walls, as appropriate. Wall pressures for the expected soil conditions are presented in the permanent foundation and retaining walls section of this repor1. It is important that the portion of the structure above the permanent detained water level be backfilled with free-draining soil, as recommended for retaining walls. Should drainage not be provided, lhe walls must be designed for hydrostatic forces acting on the outside of the structure. The backfill for all underground structures must be compacted in lifts according to the criteria in the pervious section of this repor1. Trenches for underground structures and utilities should not cross a line extending downwards from an existing footing at an inclination of (2: 1) (Horizontal:Vertical), or a line extending downwards from a property line at an inclination of (1.5:1) (H:V). We should be consulted if these excavation zones will be exceeded for installation of storm facilities or other utilities. If the structure includes an elevator, it may be necessary to provide special drainage or waterproofing measures for the elevator pit. If no seepage into the eievator pit is acceptable, it will be necessary to provide a footing drain and free-draining wa II backfill, and the walls should be waterproofed. If the footing drain will be too low to connect to the storm drainage system, them it will likely be necessary to install a pumped sump to discharge the collected water. Alternatively, the elevator pit could be designed to be entirely waterproof; this would include designing the pit structure to resist hydrostatic uplift pressures. The erosion control measures needed during the site development will depend heavily on the weather conditions that are encountered. While site clearing will expose a large area of bare soil, the erosion potential on the site is relatively low due to the sandy soil conditions and the excavation GEOTECH CONSULTANTS, INC. N & C Investments, LLC. July 18, 2007 JN 07190 Page 5 being lower than the surrounding area. Rocked constructior, access roads should be extended into the site to reduce the amount of soil or mud carried off the property by trucks and equipment. Wherever possible, these roads should follow the alignment of planned pavements, and trucks should not be allowed to drive off of the rock-covered areas. Cut slopes and soil stockpiles should be covered with plastic during wet weather. Following rough grading, it may be necessary to mulch or hydroseed bare areas that will not be immediately covered with landscaping or an impervious surface. The drainage and/or waterproofing recommendations presented in this report are intended only to prevent active seepage from flowing through concrete walls or slabs. Even in the absence of active seepage into and beneath structures, water vapor can migrate through walls, slabs, and floors from the surrounding soil, and can even be transmitted from slabs and foundation walls due to the concrete curing process. Water vapor also results from occupant uses, such as cooking and bathing. Excessive water vapor trapped within structures can result in a variety of undesirable conditions, including, but not limited to, moisture problems with flooring systems, excessively moist air within occupied areas, and the growth of molds, fungi, and other biological organisms that may be harmful to the health of the occupants. The designer or architect must consider the potential vapor sources and likely occupant uses, and provide sufficient ventilation, either passive or mechanical, to prevent a build up of excessive water vapor within the planned structure. Geotech Consultants, Inc. should be allowed to review the final development plans to verify that the recommendations presented in this report are adequately addressed in the design. Such a plan review would be additional work beyond the current scope of work for this study, and it may include revisions to our recommendations to accommodate site, development, and geotechnical constrain1s that become more evident during the review process. We recommend including this report, in i1s entirety, in the project contract documents. This report should also be provided to any future property owners so they will be aware of our findings and recommendations. SEISMIC CONSIDERA T/ONS In accordance with Table 1613.5.2 of the 2006 International Building Code (IBC), the site soil profile within 100 feet of the ground surface is best represented by Soil Profile Type O (Stiff Soil Profile. The augercast foundation piers, recommended in this report, will be embedded into dense, non-liquefiable soils. AUGERCAST CONCRETE PIERS Augercast piers are installed using continuous flight. hollow-stem auger equipment mounted on a crane. Concrete grout must be pumped continuously through the auger as it is withdrawn. This allows the piers to be installed where caving conditions or significant groundwater are anticipated. We recommend that augercast piers be installed by an experienced contractor who is familiar with the anticipated subsurface conditions. An allowable compressive capacity of 35 tons can be attained by installing a 16-inch-diameter, augercast concrete pier at least 10 feet into dense, native sand and gravel. For transient loading, such as wind or seismic loads, the allowable pier capacity may be increased by one-third. We can provide design criteria for different pier diameters and embedment lengths, if greater capacities are GEOTECH CONSULTANTS, INC. N & C Investments, LLC. July 18, 2007 JN07190 Page 6 required. The minimum center-to-center pier spacing should bo three times the pier diameter. Based on our boring information, we estimate that pier lengths of about 35 to 40 feel will be required to achieve adequate penetration into the bearing soil. We estimate that the total settlement of single piers inslalled as described above will be on the order of one-half inch. Most of this settlement should occur during the construction phase as lhe dead loads are applied. The remaining post-cons1ruction settlement would be realized as the live loads are applied. We estimate that differential settlements over any portion of the structures should be less than about one-quarter inch. We recommend reinforcing each pier its entire length. This typically consists of a rebar cage extending a portion of the pier's length with a full-length center bar. Each pier can be assumed to have a point of fixity (poin1 of maximum bending moment) al 12 feet below the top of the pier for design of the reinforcing. The loose soil agains1 the piers can be assumed to have a design passive earth resistance of 200 pounds per cubic foot (pcf) acting on two times the pier diameter. Passive earth pressures on the grade beams will also provide some lateral resistance. If structural fill is placed against the outside of the grade beams. the design passive earth pressure from the fill can be assumed to be equal to that pressure exerted by an equivalent fiuid with a density of 200 pcf. This passive resistance is an ultimate value that does not include a safety factor. PIPE PILES This section applJes to our recommendations for the underpinning of the adjacent building south of the subject property. Three-or 4-inch-diameter pipe piles driven with a 650-or 800-or 1,100- pound hydraulic jackhammer to the following final penetration rates may be assigned the following compressive capacities. INSIIJ!i PILE J)IAMETER 3 inches FINAL DIUVJNG RATE (90-µouud l1am111er) FINAL DRIVING RATE (6'.'0-poumJ lm1111ncr) 60 sec/inch 6 sec/mch NIA •• FINAL DRIVING RATE {800-pound lmnunl!r) • • FINAL DRIVING RATE ( I , 100-pournl kHnmi;;"r) 6 sec/inch ALLOWAllLE COMPRESSIVE CAPACITY .. 6 tons Note: The refusal criteria indic-a1ed in !he above 1able are valid only for pipe piles that are installed using a hydraulic impact hammer carried on leads that allow the hammer Jo sit on the lop of the pile during driving. If the piles are installed by alternative methods, such as a vibratory hammer or a hammer that is hard-mounted to the Installation machine, numerous load tests to 200 percent of the design capacity would be necessary to substantiate the allowable pile load. The appropriate number of load tests would need to be determined al the time the contractor and installation method are chosen. As a minimum, load tests on 20 percent o! the piles is typical where alternative pile installation methods are used. As a minimum. Schedule 40 pipe should be used. The site soils should not be highly corrosive. Considering this, it is our opinion that standard "black" pipe can be used, and corrosion protection, such as galvanizing, is not necessary for the pipe piles. Based on the planned excavation depth and our borings, we recommend a minimum pile length of 20 feet to achieve embedmen1 into dense, native soils. Our experience with installation of small- diameter pipe piles indicates that ii is likely that the piles will be longer than this minimum length. GEOTECH CONSULTANTS. INC. N & C Investments, LLC. July 18, 2007 JN 07190 Page 7 Pile caps, grade beams, or brackets should be used to transmit loads to the piles. Isolated pile caps should include a minimum of two piles to reduce the potential for eccentric !oads being applied to the piles. Subsequent sections of pipe can be connected with slip or threaded couplers, or they can be welded together. If slip couplers are used, they should fit snugly into the pipe sections. This may require that sh•ms be used or that beads of welding flux be applied to the outside of the coupler. PERMANENT FOUNDATION AND RETAINING WALLS Retaining walls backfilled on only one side should be designed to resist the latera! earth pressures imposed by the soil they retain. The following recommended parameters are for walls that restrain level backfill: r--·------~--, l',\llAMETER \'ALlffi I c1ve a At ErthP res sure 35 p f C Passive Earth Pressure 300 pcf Soil Unit Weight 130 pcf Where: (iJ pct is pounds per coble foot, and (ii) active and passive earth pressures are computed using the equivalent fluid pressures. • For a restrained w.stl that canno1 deflect at least 0.002 times its height, a untform latEiral pressure equal to 10 psf times the helght or the wal! should be added to the above active aqulvBlent fluld pressure. I ! The values given above are to be used to design permanent foundation and retaining walls only. The passive pressure given is appropriate for the depth of level structural fill placed in front of a retaining or foundation wall only. The value for passive resistance is an ultimate value and does not include a safety factor. We recommend a safety factor of at least 1 5 for overturning and slid:ng, when using the above values to design the walls. Restrained wall soil parameters should be utilized for a distance of 1.5 times the wall height from corners or bends in the walls. This is intended to reduce the amount of cracking that can occur where a wall is restrained by a comer. The design values given above do not include the effects of any hydrostatic pressures behind the walls and assume that no surcharges, such as those caused by slopes, vehicles, or adjacent foundations will be exerted on the walls. If these conditions exist, those pressures should be added to the above lateral soil pressures. Where sloping backfill is desired behind the walls, we will need to be given the wall dimensions and the slope of the backfill in order to provide the appropriate design earth pressures. The surcharge due to traffic loads behind a wall can typically be accounted for by adding a uniform pressure equal to 2 feet multiplied by the above active fluid density. Heavy construction equipmen1 should not be operated behind retaining and foundation walls within a distance equa, to the height of a wall, unless the walls are designed for the additional lateral pressures resulting from the equipment. The wall design criteria assume that the backfill will be well-compacted in lifts no thicker than 12 inches. The compaction o/ backfill near the walls should GEOTECH CONSULT ANTS. iNC. N & C Investments, LL C. July 18, 2007 JN 07190 Page 8 be accomplished with hand-operated equipment to prevent the walls from being overloaded by the higher soil forces that occur during compaclion. Retaining Wall Backfill and Waterproofing Backfill placed behind retaining or foundation walls should be coarse, free-draining structural fill containing no organics. This backfill should contain no more than 5 percent silt or clay particles and have no gravel greater than 4 inches in diameter. The percentage of particles passing the No. 4 sieve should be between 25 and 70 percent. If the native sand and gravel is used as backfill, a drainage composite similar to Miradrain 6000 should be placed against the backfilled retaining walls. The drainage composites should be hydraulically connected to the foundation drain system. Free-draining backfill or gravel should be used for the entire width of the backfill where seepage is encountered. For increased protection, drainage composites should be placed along cut slope faces, and the walls should be backfilled entirely with free-draining soil. The later section entitled Drainage Considerations should also be reviewed for recommendations related to subsurface drainage behind foundation and retaining walls. The purpose of these backfill requirements is to ensure that the design criteria for a retaining wall are not exceeded because of a build-up of hydrostatic pressure behind the wall. The top 12 to 18 inches of the backfill should consist of a compacted, relatively impermeable soil or topsoil, or the surface should be paved. The ground surface must also slope away from backfilled walls to reduce the potential for surface water to percolate into the backfill. The section entitled General Earthwork and Structural Fill contains recommendations regarding the placement and compaction of structural fill behind retaining and foundation walls. The above recommendations are not intended to waterproof below-grade walls, or to prevent the formation of mold, mildew or fungi in interior spaces. Over time, the performance of subsurface drainage systems can degrade, subsurface groundwater flow patterns can change, and utilities can break or develop leaks. Therefore, waterproofing should be provided where future seepage through the walls is not acceptable. This typically includes limiting cold-joints and wall penetrations, and using bentonite panels or membranes on the outside of the walls. There are a variety of different waterproofing materials and systems, which should be installed by an experienced contractor familiar with the anticipated construction and subsurface conditions. Applying a thin coat of asphalt emulsion to the outside face of a wall is not considered waterproofing, and will only help to reduce moisture generated from water vapor or capillary action from seeping through the concrete. As with any project, adequate ventilation of basement and crawl space areas is important to prevent a build up of water vapor that is commonly transmitted through concrete walls from the surrounding soil, even when seepage is not present. This is appropriate even when waterproofing is applied to the outside of foundation and retaining walls. We recommend that you contact a specialty consultant if detailed recommendations or specifications related to waterproofing design, or minimizing the potential for infesta1ions of mold and mildew are desired. The General, Slabs-On-Grade, and Drainage Considerations sections should be reviewed for addi1ional recommendations related to the control of groundwater and excess water vapor for the anticipated construction. [':;F()TFr.H r.ON!=i! JLT ANT~ IN(: N & c Investments, LLC. Juiy 18, 2007 SLABS-ON-GRADE JN 07190 Page 9 If some potential for post construction settlement and cracking can be tolerated, the garage floors can be constructed as slabs-on-grade atop a minimum of 12 hches of compacted structural fill over native soils.,. To reduce the magnitude of the slab cracking we recommend reinforcing the slabs with a minimum of No. 4 rebar piaced on 18-inch centers each way. The subgrade soil must be in a firm, non-yielding condition at the time of slab construction or underslab fill placement. Any soft areas encountered should be excavated and replaced with additional select, imported structural fill. Living space slabs and slabs where no potential for settlement is acceptable should be structurally supported by the piling Even where the exposed soils appear dry. water vapor will tend to naturally migrate upward through the soil to the new constructed space above it. All interior slabs-on-grade must be underlain by a capillary break or drainage layer consisting of a minimum 4-inch thickness of grave! or crushed rock that has a fines content (percent passing the No. 200 sieve) of less than 3 percent and a sand content (percent passing the No. 4 sieve) of no more than 10 percent. This capillary break/drainage layer is no! necessary if an underslab drainage system is installed. As noted by the American Concrete Institute (ACI) in the Guides for Concrete Floor and Slab Structures, proper moisture protection is desirable immediately belcw any on-grade slab that will be covered by tile, wood, carpet, impermeable floor coverings, or any moisture-sensitive equipment or products. ACI also notes that vapor retarders, such as 6-mil plastic sheeting, are typically used. A vapor retarder is defined as a material with a perm ea nee of less than 0.3 US perms per square fool (psf) per hour, as determined by ASTM E 96. It is possible that concrete admixtures may meet this specification, although the manufacturers of the admixtures should be consulted. Where plastic sheeting is used under slabs, joints should overlap by at least 6 inches and be sealed with adhesive tape. The sheeting should extend to the founda1ion walls for maximum vapor pro1edion. If no potential for vapor passage through the slab is desired. a vapcr barrier should be used. A vapor barrier, as defined by ACI, is a product with a water transmission rate of 0.00 perms per square foot per hour when tested in accordance with ASTM E 96. Reinforced membranes having sealed overlaps can meet this requirement. In the recent past, ACI (Section 4.1.5) reGommended that a minimum oi 4 inches of well-graded compactable granular material. such as a 518 inch minus crushed rock pavement base, should be placed over the vapor retarder or barrier for protection of the retarder or barrier and as a "blotter" to aid in the curing of the concrete slab. Sand was not recommended by ACI for this purpose. However, the use of material over the vapor retarder is controversial as noted in current ACI literature because of the potential that the protection/blotter material can become we1 between the time of its placement and the inslailation of the slab. If the material is wet prior to slab placement, which is always possible in the Puget Sound area, it could cause vapor transmission to occur up through the slab in the future, essentially destroying the purpose of the vapor barrier/retarder. Therefore, if there is a potential that the protection/blotter material will become wet before the slab is installed, ACI now recommends that no protection/blotter material be used. However, ACI then recommends that, because there is a potential for slab cure due to the loss of the blotter material, joint spacing in the slab be reduced, a low shrinkage concrete mixture be used, and "other measures" (steel reinforcing, etc.) be used. ASTM E-1643-98 "Standard Practice for Installation of Water Vapor Retarders Used in Contact with Earth or Granular Fill Under Concrete Slabs" generally agrees with the recent AC! literature. We recommend that the contractor, the project materials engineer, and the owner discuss these issues and review recent AC! literature and ASTM E-1643 for installation guidelines and guidance G!;OTECH CONSULTANTS INC. N & C Investments, LLC. July 18, 2007 JN07190 Page 10 on the use of the protection/blotter material. Our opinion is that with impervious surfaces that all means should be undertaken to reduce water vapor transmission. The General, Permanent Foundation and Retaining Walls, and Drainage Considerations sections should be reviewed for additional recommendations related to the control of groundwater and excess water vapor for the anticipated construction. Isolation joints should be provided where the slaos intersect columns and walls. Control and expansion joints should also be used to control cracking from expansion and contraction. Saw cuts or preformed strip joints used to control shrinkage cracking should extend through the upper one- fourth of the slab. The spacing of control or expansion joints depends on the slab shape and the amount of steel placed in it. Reducing the water-to-cement ratio of the concrete and curing the concrete, by preventing the evaporation of free water until cement hydration occurs, will also reduce shrinkage cracking. EXCA VA T/ONS AND SLOPES Excavation slopes should not exceed the limits specified in local, state, and national government safety regulations. Temporary cuts to a depth of about 4 feet may be attempted vertically in unsaturated soil, if there are no indications of slope instability. However, vertical cuts should not be made near property boundaries, or existing utilities and structures. Based upon Washington Administrative Code (WAC) 296, Part N, the soil at the subject site would generally be classified as Type C. Therefore, temporary cut slopes greater than 4 feet in height should not be excavated at an inclination steeper than 1.5:1 (Horizontal:Vertical), extending continuously between the top and the bottom of a cut. In addition, no unshared cuts should be made within a 2:1 (H:V) inclination of any existing footings. The above-recommended temporary slope inclination is based on the conditions exposed in our explorations, and on what has been successful at other sites with similar soil conditions. It is possible that variations in soil and groundwater conditions will require modifications to the inclination at which temporary slopes can stand. Temporary cuts are those that will remain unsuppor1ed for a relatively short duration to allow for the construction of foundations, retaining walls, or utilities. Temporary cut slopes should be protected with plastic sheeting during wet weather. It is also important that surface water be directed away from temporary slope cuts. The cut slopes should also be backfilled or retained as soon as possible to reduce the potential for instability. Please note that loose soil can cave suddenly and without warning. Excavation, foundation, and utility contractors should be made especially aware oJ this potential danger. These recommendations may need to be modified if the area near the potential cuts has been disturbed in the past by utility installation, or if settlement-sensitive utilities are located nearby. All permanent cuts into native soil should be inclined no steeper than 2:1 (H:V). To reduce the potential for shallow sloughing, fill must be compacted tc the face of these slopes. This can be accomplished by overbuilding the compacted fill and then trimming it back to its final inclination. Adequate compaction of the slope face is impor1ant for long-term stability and is necessary to prevent excessive settlement of patios, slabs, foundations, or other improvements that may be placed near the edge of the slope. Water should not be allowed to flow uncontrolled over the top of any temporary or penmanent slope. All permanently exposed slopes should be seeded with an appropriate species of vegetation to reduce erosion and improve the stability of the surficial layer of soil. r::F=nTF=f:H r.CiNSl JI TANTS INf': N & C Investments, LLC July 18, 2007 TEMPORARY SHORING JN 07190 Page 11 A variety of shoring systems are feasibie for use at this site. This section presents design considerations for cantilevered or tied-back soldier-pile walls. Since the most suitable choice is primarily dependent on a number of factors under the contractor's control, we suggest that the contractor work closely with the structural engineer during the shoring design. As discussed above, the sensitivity of adjacent buildings and utilities must be considered in the design to reduce the risk of causing settlemenl of these adjacent elemen1s. Regardless of the system used, all shoring systems will defiect in toward the excavation. Therefore, there is always a risk of noticeable settlement occurring on lhe ground behind the shoring wall. These risks are reduced, but not entirely eliminated, by using more rigid shoring systems, such as soldier piles. The shoring design should be submitted to Geotech Consultants, Inc. For review prior to beginning site excavation. We are available and would be pleased to assist in this design effort. CANTILEVERED AND TIED-BACK SOLDIER PILES Soldier-Pile Installation Soldier-pile walls would be constructed after making planned cut slopes, and prior to commencing the mass excavation, by setting steel H-beams in a drilled hole and grouting the space between the beam and the soi; with concrete for the entire height of the drilled hole. We anticipate that the holes would require casing, the contractor should be prepared to case the holes or use the slurry method if caving soil is encountered. Excessive ground loss in t.ne drilled holes must be avoided to reduce the potential for settlement on adjacent properties. If water 1s present in a hole at the time the soldier pile is poured, concrete must be tremied to the bottom of the hole. As excavation proceeds downward, the space between the piles should be lagged with timber, and any voids behind the timbers should be filled with pea gravel, or a slurry comprised of sand and fly ash Treated lagging is usually required for permanent walls, while untreated lagging can often be utilized for temporary shoring walls. Temporary vertical cuts will be necessary between the soldier piles for the Jagging placement. The prompt and careful installation of lagging is important, particularly in loose or caving soil, to maintain the integrity of the excavation and provide safer working conditions. Additionally, care must be taken by the excavator to remove no more soil between the soldier piles than is necessary to install the lagging. Caving or overexcavation during lagging placement could result in loss of ground on neighboring properties. Timber lagging should be designed for an applied lateral pressure of 30 percent of the design wall pressure, if the pile spacing is less than three pile diameters. For larger pile spacings, the lagging should be designed for 50 percent of the design load. If permanent building walls are to be constructed against the shoring walls, drainage should be provided by attaching a geotextile drainage composite with a solid p:astic backing, similar to Miradrain 6000, to the entire face of the lagging, prior to placing waterproofing and pouring the foundation wall. These drainage composites should GEOTECH CONSULTANTS. INC. N & C Investments, LLC. July 18, 200 7 JN0719D Page 12 be hydraulically connected to lhe foundation drainage system through weep holes placed in the foundation walls. Soldier-Pile Wall Design Temporary soldier-pile shoring that is cantilevered or restrained by one row of tiebacks, and that has a level backslope, should be designed for an active soil pressure equal to that pressure exerted by an equivalent fluid with a unit weight of 35 pounds per cubic foot (pcf). For the shoring a long the southern property line adjacent to the existing building, we recommend that an at rest soil pressure oi 55 pcf be utilized in the shoring design to reduce the lateral deflections in this wall. Traffic surcharges can typically be accounted for by increasing the effective height of the shoring wall by 2 feel. Existing adjacent buildings will exert surcharges on the proposed shoring wall. unless the buildings are underpinned. Slopes above the shoring walls will exert additional surcharge pressures. These surcharge pressures will vary, depending on the configuration of the cut slope and shoring wall. For a 1.5: 1(H:V) cut slope above the shoring a uniform lateral surcharge ·of 20(S) psi should be applied (where S is the height of the cut slope in feet). We can provide recommendations regarding building surcharge pressures if necessary when the preliminary shoring design is completed. It is important that the shoring design provides sufficient working room to drill and install the soldier piles. without needing to make unsafe, excessively steep temporary cuts. Cut slopes should be planned to intersect the backside of the drilled holes, not the back of the lagging. Lateral movement of the soldier piles below the excavation level will be resisted by an ultimate passive soil pressure equal to that pressure exerted by a fluid with a density of 350 pcf. No safety factor is included in the given value. This soil pressure is valid only for a level excavation in front of the soldier pile; it acts on lwo times the grouted pile diameter. C~t slopes made 1n front of shoring walls significantly decrease the passive resistance. This includes temporary cuts necessary to install internal braces or rakers. The minimum embedment below the floor of the excavation for cantilever soldier piles should be equal to the height of the "stick-up." Tied-back soldier piles should be embedded no less than 10 feet below the lowest point of the excavation, including looting and utility excavations. The vertical capacity of soldier piles to carry the downward component of the tieback forces will be developed by a combination of frictional shaft resistance along the embedded length and pile end-bearing. -2-U?JM#M; ..... rtttftlf'l«W ~ile Shafi Fric!io~ 800 psf ~ Where: (I) psf is pounds per s~uare foot. The above values assume that the excavation is level in front of the soldier pile and that the bottom of the pile is embedded a minimum of 10 feet below the floor of the excavation. The concrete surrounding the embedded portion of the pile must have ~i=nTr:r:H r.nN~I 11 TANT:c; IN('; N & C Investments, LLC. July 18, 2007 JN 07190 Page 13 sufficient bond and st:ength to transfer the vertical load from the steel section through tr,e concrete into !he soil. EXCAVATION AND SHORING MONITORING As with any shoring system, there is a potential risk of greater-than-anticipated movement of the shoring and the ground outside of the excavation. This can translate into noticeable damage of surrounding on-grade elements, such as foundations and slabs. Therefore, we recommend making an extensive photographic and visual survey of the project vicinity, prior to demolition activities, installing shoring or commencing excavation. This documents the condition of buildings, pavements, and utilities in the immediate vicinity of the site in order to avoid, and protect the owner from, unsubstantiated damage claims by surrounding property owners. Additionally, the shoring walls, and any adJacent foundations should be monitored during construction to detect soil movements. To monitor their performance, we recommend establishing a series of survey reference points to measure any horizontal deflections of the shoring system. Control points should be established at a distance well away from the walls and slopes, and deflections from the reference points should be measured throughout construction by survey methods. At least every third soldier pile should be monitored by taking readings at the top of the pile. Additionally, benchmarks installed on the surrounding buildings should be monitored for at least vertical movement. We suggest taking the readings at least once a week, until it is established that no deflections are occurring. The initial ,eadings for this monitoring should be taken before starting any demolition or excavation on the site. DRAINAGE CONSIDERATIONS We anticipate that permanent foundation walls (will/may) be constnucted against the shoring walls. Where this occurs, a plastic-backed drainage composite, such as Miradrain, Battledrain, or similar, should be placed agains1 the entire surface of the shoring prior to pouring the foundation wall. Weep pipes located no more than 6 feet on-center should be connected to the drainage composite and poured into the foundation walls or the perimeter footing. A footing drain installed along the inside of the perimeter footing will be used to collect and carry the water discharged by the weep pipes to the storm system. Isolated zones of moisture or seepage can still reach the permanent wall where groundwater finds leaks or joints in the drainage composite. This is often an acceptable risk in unoccupied below-grade spaces, such as parking garages. However, formal waterproofing is typically necessary in areas where wet conditions at the face of the permanent wall will not be tolerable. If this is a concern, the permanent drainage and waterproofing system should be designed by a specialty consultant familiar with the expected subsurface conditions and proposed construction. Footing drains placed inside the building or behind backfilled walls should consist of 4-inch, perforated PVC pipe surrounded by at least 6 inches of 1-inch-minus, washed rocx wrapped in a non-woven, geotextile filter fabric (Mirafi 140N, Supac 4NP, or similar material). At its highest point, a perforated pipe invert should be at least 6 inches below the level of a crawl space or the bottom of a floor slab, and it should be sloped slightly for drainage. Plate 11 presents typical considerations for footing drains. All roof and surface water drains must be kept separate from the foundation drain system. GEOTe:CK CONSULTANTS. INC. N & C Investments, LLC. July 18, 2007 JN 07190 Page 14 If the structure includes an elevator, it may be necessary to provide special drainage or waterproofing measures for the elevator pi1. If no seepage into the elevator pit is acceptable, it will be necessary to provide a footing drain and free-draining wall backfill, and the walls should be waterproofed. If the footing drain will be too low 10 connect to the storm drainage system, then it will likely be necessary to install a pumped sump to discharge the collected water. Alternatively, the elevator pit could be designed to be entirely waterproof; this would include designing the pit structure to resist hydrostatic uplift pressures. Groundwater was observed during our fieid work. If seepage is encountered in an excavation, it should be drained from the site by directing it through drainage drtches, perforated pipe, or French drains, or by pumping it from sumps interconnected by shallow connector trenches at the bottom of the excavation. The excavalion and site should be graded so thal surface weter is directed off the site and away from the tops of slopes. Water should nol be allowed to stand in any area where foundations. slabs, or pavements are to be constructed. Final site grad·,ng in areas adjacent to the building should slope away at least 2 percent, except where the area is paved. Surface drains should be provided where necessary to prevent ponding of waler behind foundation or retaining walls. GENERAL EARTHWORK AND STRUCTURAL FILL All building and pavement areas should be stripped of surface vegetation. topsoil, organic soil, and other deleterious material. The stripped or removed materials should not be mixed with any materials to be used as structural fill, but they could be used in non-structural areas, such as landscape beds. Structural fill is defined as any fill, including utility backfill, placed under, or close to, a building, behind permanent retaining or foundation walls, or in other areas where the underlying soil needs to supporl loads. All structural fill should be placed in horizontal lifts with a moisture content at, or near, the optimum moisture content. The optimum moisture cmter.1 is that moisture content that results in the greatest compactec' dry density. The moisture content of fill is very important and must be closely controlled during the filling and compaction process. The on-site sand and gravel is well suited for reuse as structural fill. The allowable thickness of the fill Ifft will depend on the material type selected, the compaction equipment used, and the number of passes made to compact the lift The loose lift thickness should not exceed 12 inches. We recommend testing the fill as it is placed. If the fill is not sufficiently compacted, ii can be recompacted before another lift is placed. This eliminates the need to remove the fill lo achieve the required compaction. The following table presents recommended relative compactions for structural fill, c..i=nn:r.H r.nN~I JI TANT.C. IN(; N & C Investments, LLC. July 18, 2007 ' Beneath footings, slabs or wa!kwa s ! Filled slopes and behind 95% 90% retaini.ng walls ...... --+-cc-.,~~-~. 95% for upper 12 inches of subgrade; 90% below that level Beneath pavements Where: Minimum Relative Compaction is !hi: ratio, expressed in percentages, of the compacted dry density lo the maximum dry density, as determini:d In accordance with ASTM )est Designation O 1557-91 {Modified Proclm). JN 07190 Page 15 Structural fill that will be placed in we, weather should consist of a coarse, granular soil with a silt or clay content of no more than 5 percent. The percentage of particles passing the No. 200 sieve should be measured from that portion of soil passing the three-quarter-inch sieve. L/MITA T/ONS The conclusrons and recommendations contained in this report are based on site conditions as they existed at the time of our exploration anc assume that the soil and groundwater conditions encountered in the borings are representative of subsurface conditions on the site. If 1he subsurface conditions encountered during construc1ion are significantly different from those observed in our explorations. we should be advised at once so that we can review these conditions and reconsider our recommendations where necessary. Unanticipated soil conditions are commonly encountered on construction sites and cannot be fully anticipated by merely taking soil samples in borings. Subsurface conditions can also vary between exploration locations. Such unexpected conditions frequently require making additional expenditures to attain a properly cor.structed project It is recommended that the owner consider providing a contingency fund to accommodate such potential extra costs and risks. This is a standard recommendation for all projects. This repor1 has been prepared for the exciusive use of N&C Investments . and its representatives, for specific application to this project and site. Our recommendations and conclusions are based on observed site materials. and engineering analyses. Our conclusions and recommendations are professional opinions derived in accordance with current standards of practice within the scope of our seNices and within budget and time constraints. No warranty is expressed or implied. The scope of our services does not include services related to construction safety precautions, and our recommendations are not intended to direct the contractor's methods, techniques, sequences, or procedures, except as specifically described in our repor1 for consideration in design. Our services also do not include assessing or minimizing the potential for biological hazards, such as mold, bacteria, mildew and fungi in either the existing or proposed site development. ADDITIONAL SERVICES In addition to reviewing the final plans, Geotech Consultants, Inc. should be retained to provide geotechnical consultation, testing, and observation services during construction. This is to confirm c:;.c::OTECH CONStJL TANTS. INC. N & C Investments, LL C. July 18, 2007 JN 07190 Page 16 that subsurface conditions are consistent with those indicated by our exploration, to evaluate whether earthwork and foundation construction activities comply with the general intent of the recommendations presented in this report, and to provide suggestions for design changes in the event subsurface conditions differ from those anticipated prior to the start of construction. However, our work would not include the supervision or direction of the actual work of the contractor and its employees or agents. Also, job and site safety, and dimensional measurements, will be the resoonsibility of the contractor. During the construction phase, we will provide geotechnical observation and testing services when requested by you or your representatives. Please be aware that we can only document site work we actually observe. It is still the responsibility of your contractor or on-site construction team to verify thal our recommendations are being followed, whether we are present at the site or not. The scope of our work did not include an environmental assessment. but we can provide this service, if requested. The following plates are attached to complete this report: Plate 1 Plate 2 Plates 3-10 Plate 11 Vicinity Map Site Exploration Plan Test Boring Logs Typical Footing Drain Detail We appreciate the opportunity to be of service on this project. If you have any questions, or if we may be of further service, please do not hesitate to contact us. ZJM/JHS: jyb t'§XP'fj£S 01-a1-a e, Respectfully submitted, GEOTECH CONSULTANTS, INC. Zack J. Munstermann Geotechnical Engineer James H. Strange, Jr., P.E. Project Manager ~FnTFr.H r.nNSI fl TANT.S INC:: GEOTECH CONSULTA'ITS, INC. i t, VICINITY MAP 207 -219 Main Avenue South Renton, Washington I Job No: · 07190 I Date: July 2007 I Plate: legend: >, Q) "' South 2nd Street r ··-· ·-·· -··-·· -··-·. -·· -. ·-·· -··-··~ B·S " j " 8-6 : I Existing Existing Building Building B-7 " " B-1 " 8·2 . j B-3 B-4,,. : " .,, '··-· ·-·· -. ·-··-,,_ .. ,_ ··-· ·-··-·· -··- .c -:, 0 tf) Q) :, C "' > <I: C <ti ~ 0 Test boring location GEOTECH CONSULTA<'..rS, INC. )3 SITE EXPLORATION PLAN 207 -219 Main Avenue South Renton, Washington Job No: I Date: I jPlafe; 07190 July 2007 No Scale 2 --- 1- 5 ,-. ... ... ... ... 101-- 1- .... .... .... 15 1- 1-- 1-- .... .... 20 1-.. ... 25 f-.. --... 30 f- c.. - -- 35 1- - 40 - 15 3 4 62 871 10.5 ' BORING 1 Description Brown SAND ar1d gravel, medium-to coa~se-grained, moist, loose -becomes Iron stained, wltti some fine-grained sand, wet, very dense * Test boring was terminated at 39 feet on June 14, 2007. * Groundwater seepage was encountered at 25 feet during drilling. BORING LOG GEOTECH 207 -219 Main Avenue South Renton, Washington CONSULTANTS, INC Job Date: 07190 Jul 2007 Logged by: Plate: ZJM -3 35 5 22 10 14 15 51 20 25 25 63 30 50 35 47 40 . BORING 2 Description • Test boring was terminated at 39 feet on June 14, 2007. • Groundwater seepage was encountered at 20 feet during drilling. GEOTECH CONSULTANTS, INC. Job BORING LOG 207 -219 Main Avenue South Renton, Washington Date: 07190 Jul 2007 Logged by: Plate: ZJM 4 L- L- ~ ~ 5 -.... .... .... L- 10 ---... .... ... 15 ..... L- L-.... .... 20 - '---- 25 ...... L.. y --- 30 -L- L--- 35 -L- L-... ~ 40 .__ 3 17 8 23 51 26 48 52 68 79111 • BORING 3 Description Aspf-:alt ovef FILL 5/8'' ml.ius crushed rock Brown SAND, fine· to rnediurTl-gr3ir1-cd,-V8ry moisi: locse BroWn SAND and graV'e!, medium~ to coarse-gr2ined~ very moist. medium=-dense -becomes loose -becomes medium-dense -becomes dense * Test boring was terminated at 39 feet on June 14, 2007. • Groundwater seepage was encountered at 26 feet during drilling. GEOTECH CONSULTANTS, INC. BORING LOG 207 -219 Main Avenue South Renton, Washington Job Date: 07190 July 2007 Logged by: ZJM 5 10 15 20 25 30 35 40 ----------- I--... .._ ... -----... --------.. I- I---- I- I- -- 3 5 0 3 BORING 4 Description 5/8" minus crushed rock FILL 1 lf---+~B-ro_w_r~S~A~N7.D~.~fi~n-e-~t-o-m--e~d0iu-m:,grained, moist. loose (Fi/J) 2 I 3 I 41 FILL Brown SAND and gravel, fine-to coarse-grained, very moist, very loose -glass shards -becomes dense -becomes very dense * Test boring was terminated at 39 feet on June 14, 2007. * Groundwater seepage was encountered at 24 feet during drilling. ~ii ~!gT~S~J! BORING LOG 207 -219 Main Avenue South Renton, Washington ~loo ..... """'""""""""""""" ..... """"""""' .... $ ~"";.> Job Date: Logged by: Plate: 07190 Jul 2007 ZJM 6 L.. ... ... - 5 1,.---... ... 1 0 '-- L... --- 1 5 -.... .... .... .... 2 0 ---.... L. 25 .__ L.. L.. .... ~ 30 --.... .... .... 35 '----.... .... 40 ...... 4 12 42 40 8 27 32 62 BORING 5 Description Asphalt over 1" minus crushec' rock Brown SAfib",-fins-to rnedium~grained, mcist, laO_s_e ___________ ----- Brnwn SAND and gravel. fine-to coarse-grained, moist, medium-dense • becomes medium-to coarse-grained, dense -becomes dense -becomes very dense ' Test boring was termmated at 39 feet on June 14, 2007. • Groundwater seepage was encountered at 24 feet during drilling. GEOTECH CONSULTANTS, INC. Job BORING LOG 207 -219 Main Avenue South Renton, Washington 07190 2007 Logged by: Plate: ZJM 7 5 10 15 20 25 30 35 40 21 8 20 28 6 42 76 66 FILL BORING 6 Description Brown, silly SANO with gravel, fine-to medium~grained, very moist, loose to medium-dense (Fill) ' Test boring was terminated at 39 feet on June 14, 2007. • Groundwater seepage was encountered at 24 feet during drilling. ~i/ ~~'2J!s~™1!. BORING LOG 207 -219 Main Avenue South Renton, Washington ~~~~~==---Job Date: Logged by: Plate: 8 07190 Jul 2007 ZJM I- I- I-18 I- 5 I- I---13 - 1 0 I-.... .... .... 24 L.. 15 1-- L.. L L.. 50/5.5 L.. 20 1-- - '- ~ 33 I- 25 1--.... '-... ... 22 - 30 I- L.. L.. '-78/ -11.5 35 -... '- '-71111 - 40 L_ ' > BORING 7 Description Brown SANO and grave!, fine-to rnedlurn-graineC, moist, medium-dense (Fil{) 1 I I FILL 2 3 I -pea gravel ... "-~. Brown SAND and gravel, medium-to coarse-grained, very moist, del"lse ol'o" • 2, : ... ~ ..• ~ 0 .: o~<>-., ~,;: ,..~ =-r •. ~::,:. I 4 ' •. e a:.' ol • 0 •<, .. ~ C O \ <'':, ·~ C 0 p.• { J; o~.., .. o: ~. ottl•c· ,;; •() II to ' '. • () 0 ""! ""; • r·• "<'I 1/o " C, 0 0 "' ......... ~ <;> 5 , ., '~t-· !~~ ~'lo () "< .. ,, l ,Jc•" .,"'I p_D "'o }o• l.C. <> ( 0 { •• c ~ .. ts.·· F ; 6 I ."')~;~~ Pt .. to~" E," {'.,/'"'t~ .,,"'"'· ~ .... t.r <> .. ~ " ! ; ,i.,"'.; o':,..;t"} l,c,'~ Co .. ~C' I 'r.J! ~ 7 .. (l ,,.c -becomes very dense '"~ t ." ,,"" ot'll•,, • '-' "'-!",,.c·.,~ C> " .. ,,, ... t .. ~l • 'i, )".:,' c;~: ~~., " •,· ' paoo , ~ ........ I, <;)•c' " 8 ~ 1' "; 0(" C <?0" "O!, "A~.~~r"'! • Test boring was terminated at 39 feet on June 14, 2007. ' Groundwater seepage was encountered at 25 feel during drilling. BORING LOG GEOTECH 207 -219 Main Avenue South Renton, Washington CONSULTANTS, INC. Job Date: Logged by: Plate: 07190 Jul 2007 ZJM 9 Drainage composite-\ /Treated lagging Waterproofing ......._~ 4( Vapor retarder Non.woven filter fabric Washed rock or pea gravel,----...._,~ 4 .. perforated PVC drain (holes turned downward) 2" PVC weep pipe at 6' centers (Pour Into footing or wall below slabt Attach weep pipe to drainage composite. Pierce waterproofing and plastic backing of drainage composite. Soldier pile Note· Refer to the report for additional considerations related to drainage and waterproofing. GEOTECH CONSULTANTS, INC. FOUNDATION DRAIN DETAIL 207 -219 Main Avenue South Renton, Washington jJob No: 07190 I Date: Ju!y 2007 I Plate: SECTION VII -OTHER PERMITS This project will require building and grading permits. The project site is less than an acre and will not require a Construction Stormwater General Permit from the Department of Ecology. Renton Heritage Apartments DCI Engineers SECTION VIII-CSWPPP ANALYSIS & DESIGN PART A -ESC PLAN ANALYSIS AND DESIGN KCSWDM Appendix D.3 requires that the following categories of erosion sedimentation control measures be considered for every ground-disturbing project: 1. Clearing Limits: Prior to any site clearing or grading, areas to remain undisturbed during project construction shall be delineared on the project's ESC plan and physically marked on the project site. The entire site will be subject to clearing and grading. Project limits will be delineated in the field by fencing or flagging. 2. Cover Measures: Temporary and permanent cover measures shall be provided when necessary to protect disturbed areas. The intent o( these measures is to prevent erosion by having as much area as possible covered during any period of precipitation. Exposed soil will be covered or mulched within time limits detailed in the construction plans. Permanent landscape areas will be replanted as soon as practicable. 3. Perimeter Protection: Perimeter protection to filter sediment from sheet flow shall be provided downstream of all disturbed areas prior to upslope grading. Straw wattles will be installed around the perimeter of all disturbed areas along with inlet protection at catch basins impacted by construction. Barrier measures are detailed in the construction plans. 4. Traffic Area Stabilization: Unsuifaced entrances, roads, and parking areas used by construction traffic shall be stabilized to minimize erosion and tracking of sediment offsite. A quarry spall surfaced construction entrance into the site will be provided. The requirements for the entrance are detailed in the construction plans. 5. Sediment Retention: Surface water collected from all disturbed areas of the site shall be routed through a sediment pond or trap prior to release from the site, except those areas at the perimeter of the site small enough to be treated solely with perimeter protection. Sediment retention facilities shall be installed prior to grading any contributing area. It is anticipated that perimeter siltation barriers and inlet protection will provide better silt control than sediment ponds on this 0.68 acre site. The proposed project will excavate one story below grade for the proposed parking garage and foundation. All Renton Heritage Apartments DCI Engineers runoff during construction will be contained on-site. In the event water at the base of excavation does no infiltrate, baker tanks maybe utilized to settle out pumped water prior to discharge to the City's storm water conveyance system. 6. Surface Water Collection: Swface water collection measures/ e.g., ditches, berms, etc.) shall be installed to intercept all swface water from disturbed areas, convey it to a sediment pond or trap, and discharge it downstream of any disturbed areas. Areas at the perimeter of the site, which are small enough to be treated solely with perimeter protection, do not require surface water collection. Significant sources of upstream surface water that drain onto disturbed areas shall be intercepted and measures shall be installed concurrently with or immediately following rough grading and shall be designed, constructed, and stabilized as needed to minimize erosion. No significant runoff is expected to enter the site from neighboring parcels. On-site construction runoff will sheet flow across the site toward the silt barriers at the perimeter. The contractor will have the option of directing concentrated flows toward or away from specific areas as work progresses. 7. Dewateri11g Control: The water resulting from construction site de-watering activities must be treated prior to discharge or disposed of as specified. No dewatering is anticipated for this project if it is constructed during the dry season. Wet season work may require enhanced measures, including management of dewatering effluent. Ii. Dust Control: Preventive measures to minimize wind transport of soil shall be implemented when a traffic hazard may be created or when sediment transported by wind is likely to be deposited in water resources. The construction site will be sprinkled to mitigate dust issues. 9. Flow Control: Surface water from disturbed areas must be routed through the project's onsiteflow control.facility or other provisions must he made to prevent increases in the existing site conditions 2-year and JO-year runoff peaks discharging from the project site during construction. The entire existing site is impervious due to previous development on the parcels. Consequently, no construction related increase in runoff is anticipated. PART B -SWPPS PLAN DESIGN Vehicles, construction equipment and/or petroleum product storage/dispensing: • All vehicles, equipment and petroleum product storage/dispensing areas will be inspected regularly to detect any leaks or spills and to identify maintenance needs to prevent leaks or spills. • On-site fueling tanks and petroleum product storage containers shall include secondary containment. Renton Heritage Apartments DCI Engineers • Spill prevention measures, such as drip pans, will be used when conducting maintenance and repair of vehicles or equipment. • In order to perform emergency repairs on site, temporary plastic will be placed beneath and, if raining, over the vehicle. • Contaminated surfaces shall be cleaned immediately following any discharge or spill incident. Renton Heritage Apartments DCI Engineers SECTION IX -BOND QUANTITIES, FACILITY SUMMARIES & DECLARATION OF COVE~ANT Renton Heritage Apartments DCI Engineers Site Improvement Bond Quantity Worksheet Original bond computations pr&pared by: D P,~R l:IJ Sl MP'x> tJ '.l,. '1-'S"~ Date: r/ \ S'~ GO / 1.J Tel.#: 201. • g7--i?i \ r Name: PE Registration Number: Address: .fili I? ll(r!:.N G 1: RS D<-1 Firm Name: s,-.. _, .. ,:t :»-' 5 .. ~~ ~c) 5e,J--fle, \.J,t 1 ~tcl I Project No: ----------- ROAD IMPROVEMENTS & DRAINAGE FACILITIES FINANCIAL GUARANTEE REQUIREMENTS PERFORMANCE BOND•,0 AMOUNT PUBLIC ROAD & DRAINAGE MAINTENANCE/DEFECT BOND*,u Stabilization/Erosion Sediment Control (ESC) (A) Existing Right-of-Way Improvements (8) Future Public Road Improvements & Drainage Facilities (C) Private Improvements (D) Construction Bond* Amount (A+B+C+D) = TOTAL (T) Maintenance/Defect Bond"' Total NAME OF PERSON PREPARING BONO• REDUCTION: $ $ $ $ $ Minimum bond• amount is $1000. (B+C)x 0.20 = $ -'------- • NOTE: The word "bond" as used in this document means any financial guarantee acceptable to the City of Renton. -NOTE: All prices include labor, equipment, materials, overhead and profit Prices are from RS Mean.s data adjusted for the Seattle area or from local sources if not included in the RS Means database. REQUIRED BONO• AMOUNTS ARE SUBJECT TO REVIEW ANO MODIFICATION BY ROSO Page 1 of 1 REF 8-H BOND QUANTITY WORKSHEET.xis Date: Unit prices updated: 2/12/02 Version: 4/22102 Report Date: 111912010 Site Improvement Bond Quantity Worksheet GENERALITEMS"" ., •• ,,,\ :;}h'No/Y'•:r:: ,\. £,,,;,., e:,,,t,:c Backfill & Compaction-embankment Gl-11 $ 5.62 Backfill & Compaction-trench GJ-21 $ 8.53 Clear/Remove Brush, by hand Clearing/Grubbing!Tree Removal Excavation -bulk GI -3 GI -4 GI -5 Excavation -Trench I GI -6 Fencing, cedar, 6' high I GI -7 Fencing, chain link, vinyl coated, 6' high I GI -8 Fencing, chain link, gate, vinyl coated, 2Q GI -9 Fencing, split r~(I, 3' high--[GI -1 ( Fill & compact -common barrow [GI -11 Fill & compact -gravel base IG I -1 ~ Frn&-compact -screened topsoil !GI -1 ~ Gabion, 12" deep, stone filled mesh IGI -1~ Gabion, 18" deep, stone filled mesh IGI -1: Gablon, 36" deep, stone filled mesh fGI -1E Grading, firle, by hand IG! -1 Gradin~, fine, with grader !GI -·11 Monuments, 3' long IG! -1 ~ Sensitive Areas Sign IGI -2C Sodding, 1"deep, sloped ground IG! -21 Surveying, line & grade Surveying, lot location/lines Traffic control crew { 2 flaggers ) ·trail, 4" chipped wood Trail, 4" crushed cinder Trail, 4" top course Wall, retaining, concrete 1waif, rockery Page 2 of 7 Gl-2 GI -2: GI -2, GI -2 GI -21 GI -2 GI -2 l\:JI -.t. $ 0.36 $8,876.16 $ 1.50 $ 4.06 $ 18.55 $ 13.44 $1,271.81 $ 12.12 $ 22.57 $ 25.48 $ 37.85 $ 54.31 $ 74.85 $ 132.48 $ 2.02 $ 0.95 $ 135.13 $ 2.88 $ 7.46 $ 788.26 $ 1,556.64 $ 85.1B $ 7.59 $ 8.33 $ 8.19 l 44.16 T"'!l.49 SUBTOTAL REF 8-H BOND QUANTITY WORKSHEET.xis CY CY SY Acre CY CY LF LF Each LF CY CY CY SY SY SY SY SY Each Each SY Day Acre HR SY SY SY SF ~, :;·h·~/f::.· .;::,~"',f.j::.-.: doo 0.00 :~9 I .3_~~.'+I tr.!lI 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 U.U\ 0.00 1/l. i. '"l l 0.00 0.00 ··~."' :?-:~ 1::-~ 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 000 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0:00 0.00 .-,--- 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0 00 0.00 0.00 0.00 O.m 0.00 Unit prices updated: 2/12/02 Version: 4122102 Report Date: 1/1912010 Site Improvement Bond Quantity Worksheet AC Grinding, 4' wide machine< 1000sy RI· 1 $ 23.00 SY z~ -,_ 5"i , IX) 8:0II' 0.00 AC Grinding, 4' wide machine 1000-2000 RI -2 $ 5.75 SY 0.00 0.00 AC Grinding, 4' wide machine> 2000sy RI· 3 $ 1.38 SY 0.00 0.00 AC Removal/Disposal/Repair RI -4 $ 41.14 SY << I <,S,,-,(,).. 1l:CIO 0.00 Barricade, type I RI· 5 $ 30.03 LF 0.00 0.00 Barricade, type Ill ( Permanent) RI· 6 $ 45.05 LF 0.00 0.00 Curb & Gutter, rolled RI -7 $ 13.27 LF 0.00 0.00 Curb & Gutter, vertical Rl-8 $ 9.69 LF p lib.).~ 0jl[l 0.00 Curb and Gutter, demolition and disposal RI· 9 $ 13.58 LF ,-')., li;'<l.,~• = 0.00 Curb, extruded asphalt RI· 1, $ 2.44 LF 0.00 0.00 Curb, extruded concrete RI -11 $ 2.56 LF 0.00 0.00 Sawcut, asphalt, 3" depth RI -t $ 1.85 LF (,, 1,, 1 TT \0 ll:lltl 0.00 Sawcut, concrete, per 1u depth RI -1. $ 1.69 LF 0.00 0.00 Sealant, asphalt RI· 14 $ 0.99 LF 0.00 0.00 Shoulder, AC, ( see AC road unit price ) RI -1 $ . SY 0.00 0.00 Shoulder, gravel, 4" thick RI -1 $ 7.53 SY 0.00 0.00 Sidewalk, 4n thick RI· 1 $ 30.52 SY I" ~ ~~, ·z.t "TID[ 0.00 Sidewalk, 4" thick, demolition and dispos RI -1 $ 27.73 SY if'. u•,~. I~ rmr 0.00 Sidewalk, 5" thick RI -1 $ 34.94 SY 0.00 0.00 Sidewalk, SM thick, demolition and dispo~ RI· 2 $ 34.65 SY 0.00 0.00 RI· 21 $ 85.28 Each 0.00 0.00 RI· 2 $ 5.82 Each 0.00 0.00 $ 2.38 SF 0.00 0.00 Lr n "' U.uu Page 3 of7 SUBTOTAL 3 S'~l, . L(( ~ 0.00 Rl=I= H-1-i sor-in nt IANTITV INORl<'"l-<l=l=T.xls 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 O.uu 0.00 ':'"-·<.· - 0.00 0.00 0.00 0.00 0.00 0.00 000 0.00 000 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 a.oc 0.00 Unit prices updated: 2/12/02 Version: 4/22/02 Report Date: 1/1~/2010 Site Improvement Bond Quantity Worksheet ~-~ ~.,i,.;.":...1-.:,':::·~· • ',;).::.:.s''"'f&>i~5it"lJI.;,,;.;;.' ,{i.~>i'.;_~i¥'1i'10":i.:ili' · ::i:e;·.f/a',:~':-0-~4,'S!iJ,,i: 1·~i·il;~_i;;.:i:;.~t-,,;,;;/ .\.•,·-. • .-,,..;,,._ ., :, .-, For KCRS '93, (additional 2.5a base) add: RS -1 $ 3,60 SY 0,00 0,00 AC Overlay, 1.5" AC RS-2 $ 7_39 SY 0,00 0,00 AC Overlay, 2" AC RS-3 $ 8,75 SY ~ -,; ··JS'S/~ = 0,00 AC Road, 2", 4" rock, First 2500 SY RS-4 $ 17,24 SY 0,00 0,00 AC Road, 2", 4" rock, Qty. over 2500SY RS-5 $ 13,36 SY 0,00 0,00 AC Road, 3", 4" rock, First 2500 SY RS-6 $ 19,69 SY 0,00 0,00 AC Road, 3", 4" rock, Qty. over 2500 SY RS-7 $ 15,81 SY 0,00 0,00 AC Road, 5", First 2500 SY RS-8 $ 14,57 SY 0,00 0,00 AC Road, 5", Qty, Over 2500 SY RS-9 $ 13,94 SY 0,00 0,00 :AC Road, 6a, First 2500 SY ,S -1 $ 16,76 SY ~-3 ~!i5,~ 1llfO 0,00 ;AC Road, 6", Qty, Over 2500 SY -..s -1 $ 16, 12 SY 0,00 0,00 Asphalt Treated Base, 4" thick ,S -1 $ 9,21 SY om 0,00 Gravel Road, 4" rock, First 2500 SY S -1 $ 11A1 SY om 0,00 Gravel Road, 4" rock, Qty. over 2500 SY S -1· $ 7,53 SY om 0,00 PCC Road, 5", no base, over2500 SY S-1 $ 21-51 SY 0,00 0,00 PCC Road, 6", no base, over 2500 SY S -1 $ 21-87 SY 0,00 0,00 11 n1ckened r-nge ,~ -1 • b,oo Lr O,v, U,v, Page 4 of 7 SUBTOTAL J t.il .'?,?, il,00 0,00 REF 8-H BOND QUANTITY WORKSHEETxls ' ., ', ,, 0.00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0,00 0.00 0,00 0,00 U,UO 0.00 -, . ,, , ,:, ·c:-'T: 0,00 0,00 0,00 0,00 0.00 0,00 0,00 0,00 0.00 0,00 0,00 0,00 0,00 0,00 0,00 0.00 U,vv 0,00 Unit prices updated: 2112/02 Version: 4/22102 Report Date: 1/1912010 Site Improvement Bond Quantity Worksheet _ : ··" '""''' ., .. ·•.A:s:,~\;:s~·:,,i;pt,ll.uN<>ito.it;;i,,<MWM101\¥-!}i/ilvef,Wlf1"!1J(o(i~!l\#~1'i<ll'Y~~ .. m~i>.tt!"4~4"1!d'.fil"'1,'c;/r, 16.74 SY 0.00 0.00 0.00 o.ool B0113rcls--fixed 1 D-21 $ 240.74 Each 0.00 0.00 0.00 000 Bollards -removable ID -3 I $ 452.34 Each 0.00 0.00 0.00 0.00 • (CBs include frame and lid) CB Type I D-4 $1,257.64 Each (._ ~ 5° 'i $i>''-f"irn'll 0.00 0.00 0.00 CB Type IL D-5 $1,433.59 Each 0.00 0.00 0.00 0.00 CB Type II, 48" diameter D-6 $2,033.57 Each 0.00 0.00 0.00 0.00 for additional depth over 4' D-7 $ 436.52 FT 0.00 0.00 0.00 0.00 CB Type II, 54" diameter D-8 $2,192.54 Each 0.00 0.00 0.00 0.00 for additional depth over 4' D-9 $ 486.53 FT 0.00 0.00 0.00 0.00 CB Type II, 60" diameter D-10 $2,351.52 Each 0.00 0.00 0.00 0.00 for additional depth over 4' D -11 $ 536.54 FT 0.00 0.00 0.00 0.00 CB Type II, 72" diameter D-12 $3,212.64 Each 0.00 0.00 0.00 0.00 for additional depth over 4' D-13 $ 692.21 FT 000 0.00 0.00 0.00 Through-curb Inlet Framework (Add) D-14 $ 366.09 Each .,._ I f'!!i .Z Tl crJll 0.00 0.00 0 00 Cleanout, PVC, 4" D-15 $ 130.55 Each 0.00 0.00 0.00 0.00 Cleanout, PVC, 6" D-16 $ 174.90 Each 0.00 0.00 0.00 0.00 Cleanout, PVC, 8" D -17 $ 224.19 Each ?. t,.. '7) r.;;:,. I.I!"" 0.00 0.00 0.00 Culvert, PVC, 4" D -18 $ 8.64 LF 0.00 0.00 0.00 0.00 Culvert, PVC, a~ D -19 $ 12.60 LF 0.00 0.00 0.00 0.00 Culvert, PVC, 8" D -20 $ 13.33 LF 0.00 0.00 0.00 0.00 Culvert, PVC, 12" D -21 $ 21.77 LF 0.00 0.00 0.00 0.00 Culvert, CMP, 8" D-22 $ 17.25 LF 0.00 0.00 0.00 0.00 Culvert, CMP, 12" D-23 $ 26.45 LF 0.00 0.00 0.00 0.00 Culvert, CMP, 15" D-24 $ 32.73 LF 0.00 0.00 0.00 0.00 Culvert, CMP, 18" D-25 $ 37.74 LF 0.00 0.00 0.00 0.00 Culvert, CMP, 24~ D-26 $ 53.33 LF 0.00 0.00 0.00 0.00 Culvert, CMP, 30" D-27 $ 71.45 LF 0.00 0.00 0.00 0.00 Culvert, CMP, 36" D-28 $ 112.11 LF 000 0.00 0.00 0.00 Culvert, CMP, 48" D-29 $ 140.83 LF 0.00 0.00 0.00 0.00 Culvert, CMP, 60" D-30 $ 235.45 LF 0.00 0.00 0.00 0.00 uivert, L..tvir , , £ D ~ ;:s1 S .·m.,._ ,o Lr O."" U.vs O.uu 0.001 Page 5 of 7 SUBTOTAL _j~\ \i .\i\ .a;8!! 0.00 0.00 0.00 REF 8-H BOND QUANTITY WORKSHEET.xis Unit prices updated: 2/12/02 Version: 4/22/02 Repnrt n~te: 1110,.,n10 Site Improvement Bond Quantity Worksheet 6~~i~~iJg~~t~,IftiJsf~:J~ ~fiim~ffilrnii~~m,'1:r,r.;fitli\,;;;f.iri'if!~*"TI'!i'ii..1'ti~Hl'l'i'rt~f.:tc·7..,.7Fl-','.m~R~~#ii~;;;i;-5S%,!~~i;;i:~"*~ Culvert, Concrete, 8" Culvert, Concrete, 12" $ Culvert, Concrete, 15" D-34 $ 37.34 LF O o Culvert, Concrete, 18" D -35 $ 44.51 LF O <11 1 - Culvert, Concrete, 24" ID-361 $ 61.07 I LF 0 0 Culvert, Concrete. 30" ID -371 $ 104.18 I LF 0 0 Culvert, Concrete, 36" ID -381 $ 137.63 I LF 0 0 Culvert, Concrete, 42" [O -39[ $ 158.42 l LF 0 0 Culvert, Concrete, 48" ID -401 $ 175.94 I LF 0 0 Culvert,CPP,6" ID-411$ 10.10J'LF 0 0 Culvert, CPP, 8" ID -421 $ 16.10 I LF 0 0 Culvert, CPP, 12" ID -431 $ 20.70 I LF 0 0 Culvert,CPP, 15" ID-441 $ 2300 I LF 0 0 Culvert, CPP, 18" ID -451 $ 27.60 I LF 0 0 Culvert, CPP, 24" ID -461 $ 36.80 I LF 0 0 Culvert, CPP, 30" ID -411 $ 48.30 I LF 0 0 Culvert,CPP,36" ID-481 $ -55.20 I LF 0 0 Ditching ID -491 $ 8.08 I CY 0 0 Flow Dispersal Trench _i1,436 base+) ID -501 s· 25.99 I LF French Drain (3' depth) ID -51 I $ 22.60 I LF 0 0 Geotextile, laid in trench, polypropylene ID --521 $ 2.40 l -SY 0 0 Infiltration pond testing ID -531 $ 74.75 I HR 0 0 Mid-tank Access Riser, 48" dia, 6' deep ID -54[ $ 1,605.40 I Each 0 0 Pond Overflow Spillway ID -551 $ 14.01 I SY 0 0 RestrictOriOi1Sepa-F.itOr, 12" JD -56[ $·1.045.-19 ·r·taCh 0 0 Restrictor/Oil Separator, 15" ---JD -57[ $1,095.56 I Each 0 0 Restrictor/Oil Separator, 18" JD -58 [ $ 1 , 146 16 I Each 0 0 Riprap, placed ID -591 $ 39.08 I CY 0 0 Tank End Reducer (36" diameter) ID -601 $1,000.50 I Each 0 0 Trash Rack, 12" ID -61 I $ 211.97 I Each 0 0 ;Trash Rack, 15" ID-621 $ 237.27 I Each 0 0 Trash Rack, 18" -----ID-631 $ 26889 I Eacti 0 0 rash Hack, L 1 [~~4L !Ii ~U6.~ I c_ach 0 a Page 6 of 7 SUBTOTAL .'b 'S ). 'L'l.O 6' 0 REF 8-H BOND QUANTITY WORKSHEET.xis 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 l 0 a 0 0 0 0 0 0 0 0 0 0 a 0 0 0 0 0 0 0 0 0 0 0 0 0 0 a 0 0 0 Unit prices updated: 2/12102 Version: 4122102 Report Date: 1119/201 O Site Improvement Bond Quantity Worksheet ':<SURFAGING'?},U:: ~~~,:.~~'{-ffi'.~.~;~J/!~t.\;;;~~.-fl:;ti;-:J;:;:. t0?;~::-Pi::~IJ;~i~,i.fc)J;'§'t.\,i;~f.,~; ~¥~\,~, tfJ/{,~,~~~~'~t~ . .'.i''S;):7.'·:·.:;}M',f?.f~-~}.1~·.;I,1,·.~.,~ik.~iz:/~~,\f~~-~#'!A~~/);_,!·,f!~'t:-::,;'. .. ~'.:~~¥~:::;; },~:.-,\:-{';; ~::;· .:::~--~::<· -· No. 2" AC, 2" top course rock & 4" bOrfOW-PL -1 $ 1s_e4-·--sv 2" AC, 1.5" top course & 2.5" base cour PL -2 $ 17.24 SY i4" select borrow PL· 3 $ 4.55 SY 1.5M top course rock & 2.5" base course PL-4 $ 11.41 SY c6'1N•IT.EMS\'i ?::i'l'.'\2;°1J.:J''>ic.i'i-::\'\'" No WI -1 Each WI -2 SY Wl-3 CY WI -4 LF Wl-5 FT Wl-6 Wl-:-'i Wl-8 Wl-9 Wl-10 SUBTOTAL SUBTOTAL (SUM ALL PAGES): 30% CONTINGENCY & MOBILIZATION: GRANOTOT AL: COLUMN: Page 7 of 7 REF 8-H BOND QUANTITY WORKSHEET.xis 0 0 0 0 0 0 0 0 0 0 0 0 0 jj ff 0.00 , , f f?,1.l,0*'°11"' I.( 'I~ }l. l" -Mm 11 s, "·'° 0.00 B 0 0 0 0 QOO QOO 0.00 QOO 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 C 0 0 0 0 OM OM OM OM OM OM OM OM OM 0.00 0.00 0.00 0.00 0 0 0 0 0 0.00 0.00 0.00 0.00 0.00 0.00 0 00 0.00 0.00 jj 0.00 0.00 0.00 0.00 E Unit prices updated: 2112/02 Version: 4122102 Rep"'..t n"'te: 1/10/?rl10 Return Address: City Clerk's Office City of Renton 1055 S Grady Way Renton, WA 98057 DECLARATION OF COVENANT FOR INSPECTION AND MAINTENANCE OF STORMW ATER FACILITIES AND BMPS Grantor: C. DSMOS _ Ll~e.lotll'lt..if ~""'f-" f Grantee: City of Renton Legal Description: 5e..ea fk:pecl'lOLy 4 C 41TIA-C<teO) IN CONSIDERATION of the approved City of Renton pennit for application file No. LUNSWP relating to the real property ("Property") described above, the Grantor(s), the owner(s) in fee of that Property, hereby covenants(covenant) with the City of Renton, a political subdivision of the state of Washington, that he/she(they) will observe, consent to, and abide by the conditions and obligations set forth and described in Paragraphs 1 through 10 below with regard to the Property, and hereby grants(grant) an easement as described in Paragraphs 2 and 3. Grantor(s) hereby grants(grant), covenants(covenant), and agrees(agree) as follows: 1. The Grantor(s) or his/her(their) successors in interest and assigns ("Owners of the described property") shall at their own cost, operate, maintain, and keep in good repair, the Property's stormwater facilities and/or best management practices ("BMPs") constructed as required in the approved construction plans and specifications on file with the City of Renton and submitted to the City of Renton for the review and approval of pennit(s) ---~-· The property's stormwater facilities and/or best management practices ("BMPs") are shown and/or listed on Exhibit A. The property's stormwater facilities and/or BMPs shall be maintained in compliance with the operation and maintenance schedule included and attached herein as Exhibit B. Stormwater facilities include pipes, swales, tanks, vaults, ponds, and other engineered structures designed to manage and/or treat stormwater on the Property. Stormwater BMPs include dispersion and infiltration devices, native vegetated areas, permeable pavements, vegetated roofs, rainwater harvesting systems, reduced impervious surface coverage, and other measures designed to reduce the amount of stormwater runoff on the Property. 2. City of Renton shall have the right to ingress and egress over those portions of the Property necessary to perform inspections of the stormwater facilities and BMPs and conduct maintenance activities specified in this Declaration of Covenant and in accordance with RMC 4-6-030. 3. If City of Renton detennines that maintenance or repair work is required to be done to any of the stormwater facilities or BMPs, City of Renton shall give notice of the specific maintenance and/or repair work required pursuant to RMC 4-6-030. The City shall also set a reasonable time in which such Page 1 of3 Form Approved by City Attorney 10/2013 work is to be completed by the Owners. If the above required maintenance or repair is not completed within the time set by the City, the City may perform the required maintenance or repair, and hereby is given access to the Property, subject to the exclusion in Paragraph 2 above, for such purposes. Written notice will be sent to the Owners stating the City's intention to perform such work. This work will not commence until at least seven (7) days after such notice is mailed. If, within the sole discretion of the City, there exists an imminent or present danger, the seven (7) day notice period will be waived and maintenance and/or repair work will begin immediately. 4. If at any time the City of Renton reasonably determines that a stormwater facility or BMP on the Property creates any of the hazardous conditions listed in RMC 4-4-060 G or relevant municipal successor's codes as applicable and herein incorporated by reference, the City may take measures specified therein. 5. The Owners shall assume all responsibility for the cost of any maintenance or repair work completed by the City as described in Paragraph 3 or any measures taken by the City to address hazardous conditions as described in Paragraph 4. Such responsibility shall include reimbursement to the City within thirty (30) days of the receipt of the invoice for any such work performed. Overdue payments will require payment of interest at the current legal rate as liquidated damages. If legal action ensues, the prevailing party is entitled to recover reasonable litigation costs and attorney's fees. 6. The Owners are hereby required to obtain written approval from City of Renton prior to filling, piping, cutting, or removing vegetation ( except in routine landscape maintenance) in open vegetated storrnwater facilities (such as swales, channels, ditches, ponds, etc.), or performing any alterations or modifications to the stormwater facilities and BMPs referenced in this Declaration of Covenant. 7. Any notice or consent required to be given or otherwise provided for by the provisions of this Agreement shall be effective upon personal delivery, or three (3) days after mailing by Certified Mail, return receipt requested. 8. With regard to the matters addressed herein, this agreement constitutes the entire agreement between the parties, and supersedes all prior discussions, negotiations, and all agreements whatsoever whether oral or written. 9. This Declaration of Covenant is intended to protect the value and desirability of the real property described above, and shall inure to the benefit of all the citizens of the City of Renton and its successors and assigns. This Declaration of Covenant shall run with the land and be binding upon Grantor(s), and Grantor's(s') successors in interest, and assigns. 10. This Declaration of Covenant may be terminated by execution of a written agreement by the Owners and the City that is recorded by King County in its real property records. IN WITNESS WHEREOF, this Declaration of Covenant for the Inspection and Maintenance of Storrnwater Facilities and BMPs is executed this __ day of , 20 __ GRANTOR, owner of the Property GRANTOR, owner of the Property Page 2 of3 Form Approved by City Attorney 10/2013 STATE OF WASHINGTON COUNTY OF KING )ss. On this day personally appeared before me: _____ ,tome known to be the individual(s) described in and who executed the within and foregoing instrument and acknowledged that they signed the same as their free and voluntary act aud deed, for the uses and purposes therein stated. Given under my hand and official seal this __ day of ___ _ --_ ,20 __ Page 3 of3 Printed name Notary Public in and for the State of Washington, residing at My appointment expires _________ _ Form Approved by City Attorney 10/2013 Legal Description (Af'~-.JD:s:x A) LOTS 16 THROUGH 20 INCLUSIVE, BLOCK 13, PLAT OF THE TOWN OF RENTON, ACCORDING TO THE PLAT RECORDED IN VOLUME 1 OF PLATS, PAGE 135, IN KING COUNTY, WASHINGTON; EXCEPT THE WEST 5 FEET OF SAID LOT 16 DEEDED TO THE CITY OF RENTON BY QUIT CLAIM DEED RECORDED MAY 7, 1979 UNDER RECORDING NO. 7905070629; AND EXCEPT THE WEST 5 FEET OF SAID LOT 17 DEEDED TO THE CITY OF RENTON BY QUIT CLAIM DEED RECORDED MAY 7, 1979 UNDER RECORDING NO. 7905070628. SECTIO!\" X -OPERATIONS & MAINTENANCE MANUAL Renton Heritage Apartments DCI Engineern DRAINAGE FACILITIES OPERATIONS & MAINTENANCE MANUAL Renton Heritage Apartments 207-219 Main Avenue South Renton, Washington Prepared by: DCI EnG1nEERS 818 Stewart Street Seattle, WA 98101-3311 (206) 332-1900 Phone (888) 433-8130 Toll Free (206) 332-1600 Fax DCI Job No. 14012-0023 July 9, 2014 The stormwater management system for the Renton Heritage Apartments consists of a Type 1 catch basin located on Main A venue South, an open curb face frame and grate catch basin and connecting pipes. Catch basins & connecting pipes: Catch basins are located at collection points and pipe junctions. They include sumps below the outlets to store accumulated sediment. Catch basins must be inspected periodically and emptied of sediment as needed, either hy mechanical or manual means. Connecting pipes are designed to be self-flushing in large storms, and do not ordinarily require maintenance. The.following pages include drawings of the layout and details of' the drainage components, followed by maintenance guidelines from the King County Stormwater Design Manual (KCSWDM). FRAME AND VANED GRATE I IPE A LOWAN CES MAXIMUM PIPE MATERIAL INSIDE DIAMETER REINFORCED OR 12' PLAIN CONCRETE ALL METAL PIPE 15" .. CPSSP* 12· (STD. SPEC. 9--05.20) SOLID WALL PVC 15" (STD. SPEC. 9-05.12(1)) ~· PROFILE WALL PVC 15" (STD SPEC. 9-05.12(2)) * CORRUGATED POLYETHYLENE STORM SEWER PIPE ' I \ \L ONE #3 BAR HOOP FOR 6" HEIGHT TiNO #3 BAR HOOPS FOR 12" HEIGHT RECTANGULAR ADJUSTMENT SECTION #3 BAR EACH CORNER - #3 BAR EACH SIDE #3 BAR EACH WAY PRECAST BASE SECTION SEE NOTE 1 ALTERNATIVE PRECAST BASE SECTION NOTES As acceptable alternatives to the rebar shown in the PRECAST BASE SECTION, fibers (placed according to the Standard Specifications), or wire mesh having a minimum area of0.12 square inches per foot shall be used with the minimum required rebarshown in the ALTERNATIVE PRECAST BASE SECTION. Wire mesh shall not be placed in the knockouts. 2 The knockout diameter shall not be greater than 20". Knockouts shall have a wall thickness of 2" minimum to 2.5" maximum. Provide a 1.5" minimum gap between the knockout wall and the outside of the pipe. After the pipe is installed, fill the gap with joint mortar in accordance with Standard Specification 9-04.3. 3 The maximum depth from the finished grade to the lowest pipe invert shall be 5'. 4. The frame and grate must be installed with the flange down. 5. The Precast Base Section may have a rounded floor, and the walls may be sloped at a rate of 1 :24 or steeper. 6 The opening shall be measured al the top of the precast base section. 7. All pickup holes shall be grouted full after the basin has been placed. B. All grade rings and castings shall be set in mortar in accordance with Standard Specification 9-04.3. STD. PLAN -200.00 PUBLIC WORKS DEPARTMENT CATCH BASIN TYPE 1 MARCH 2008 I 1"M!N ! TYP i- HOOD--...., I i/2"MIN. SEE N0TE3 -. 29" MIN 20 114" 0 \\ \_ SEE NOTE 4 '· (TYP.) \ .. SEE NOTE 2 . (TYP.) TOP VIEW FRAME DETAIL ISOMETRIC VIEW PUBLIC WORKS DEPARTMENT :: 5 1/2" L~0 1"R 1 D .. ---r_ 1·· Ml~>-----------r -1 ~6 L----' .--ti __ OPEN I.NG HEIGf--<T \ 4" MIN \ j_ -----------.I TOP OF GRATE ------------ FRAME DETAIL SECTION (~ CATCf:! BASIN zr (::::0.58') \H ::: 3" (:: 0.25') ~'i ~~ . ,.---GRATE SEE NOTE 1 SECTION C:,.) NOTES The asymmetry of the Combination Inlet shall be considered when calculating the offset distance for the catch basin. See SECTION A. 2. The dimensions of the Frame and Hood may vary slightly among dif~ ferent manufacturers. The Frame may have cast features intended to support a grate guard. Hood units shall mount outside of the Frame. The methods for fastening the Safety Bar/ Debris Guard Rod to the Hood may vary. The Hood may include casting lugs. The top of the Hood may be cast with a pattern. 3 Attach the Hood to the frame with two 3/4" x 2" hex head bolts, nuts, and oversize washers. The washers shall have diameters adequate to assure full bearing across the slots. 4. When bolt-down grates are specified \n the contract, provide two holes in the frame that are vertically aligned with the grate slots. Tap each hole to accept a 5/8" x -11 NC x 2" a11en head cap screw. Location of bolt-down holes varies among different manufacturers. See BOLT-DOWN DETAIL 5. Only ductile iron Vaned Grates shall be used. 6 This plan is intended to show the installation details of a manufac- tured product. It is not the intent of this plan to show the specific details necessary to fabricate the castings shown on this drawing. OPEN CURB FACE FRAME AND GRATE INSTALLATION DETAIL STD. PLAN -203.00 MARCH 2008 APPENDIX A MAINTENANCE REQUIREMENTS FOR FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES NO. 5 -CATCH BASINS AND MANHOLES Maintenance Defect or Problem Condition When Maintenance is Needed Results Expected When Component Maintenance is Performed Structure Sediment Sediment exceeds 60% of the depth from the Sump of catch basin contains no bottorn of the catch basin to the invert of the sediment. lowest pipe into or out of the catch basin or is within 6 inches cf the invert of the lowest pipe into or out of the catch basin. Trash and debris Trash or debris of more than Y:z cubic foot which No Trash or debris blocking or is located immediately in front of the catch basin potentially blocking entrance to opening or is blocking capacity of the catch basin catch basin. by more than 10%. Trash or debris in the catch basin that exceeds No trash or debris in the catch basin. 1h the depth from the bottom of basin to invert the lowest pipe into or out of the basin. Dead animals or vegetation that could generate No dead animals or vegetation odors that could cause complaints or dangerous present within catch basin. gases (e.g., methane). Deposits of garbage exceeding 1 cubic foot in No condition present which would volume. attract or support the breeding of insects or rodents. Damage to frame Corner of frame extends more than % inch past Frame is even with curb. and/or top slab curb face into the street (If appllcable). Top slab has holes larger than 2 square inches or Top slab is free of holes and cracks. cracks wider than~ inch. Frame not sitting flush on top slab, i.e., Frame is sitting flush on top slab. separation of more than % inch of the frame from the top slab. Cracks in walls or Cracks wider than 1h inch and longer than 3 feet. Catch basin is sealed and bottom any evidence of soil particles entering catch structurally sound. basin through cracks, or maintenance person judges that catch basin is unsound. Cracks wider than 1h inch and longer than 1 foot No cracks more than 1 /4 inch wide at at the joint of any inlet/outlet pipe or any evidence the joint of inlet/outlet pipe. of soil particles entering catch basin through cracks. Settlement/ Catch basin has settled more than 1 inch or has Basin replaced or repaired to design misalignment rotated more than 2 inches out of alignment. standards. Damaged pipe joints Cracks wider than %-inch at the joint of the No cracks more than %-inch wide at inlet/outlet pipes or any evidence of soil entering the joint of inlet/outlet pipes. the catch basin at the joint of the inlet/outlet pipes. Contaminants and Any evidence of contaminants or pollution such Materials removed and disposed of pollution as oil, gasoline, concrete slurries or paint. according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oi! film. Inlet/Outlet Pipe Sediment Sediment frl!ing 20% or more of the pipe. Inlet/outlet pipes clear of sediment. accumulation Trash and debris Trash and debris accumulated in inlet/outlet No trash or debris in pipes. pipes (includes floatables and non-floatables). Damaged Cracks wider than %-inch at the joint of the No cracks more than %-inch wide at inlet/outlet pipes or any evidence of soil entering the joint of the inlet/outlet pipe. at the joints of the inlet/outlet pipes. 2009 Surface Water Design Manual -Appendix A 119/2009 A-9 APPENDIX A MAINTENANCE REQUIREMENTS FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES --- NO. 5-CATCH BASINS AND MANHOLES Maintenance Defect or Problem Condition When Maintenance is Needed Results Expected When Component Maintenance is Performed r------·--· Metal Grates Unsafe grate opening Grate with opening wider than 7 /8 incr,. Grate opening meets design I (Catch Basins) standards. i I Trash and debris Trash and debris that is blocking more than 20% Grate free of trash and debris. I I of grate surface. footnote to guidelines for disposal Damaged or missing Grate missing or broken member(s) of the grate. Grate is in place and meets design Any open structure requires urgent standards. maintenance. Manhole Cover/Lid Cover/lid not in place Cover/lid is missing or only partially in place. Cover/lid protects opening to Any open structure requires urgent structure. maintenance. - Locking mechanism Mechanism cannot be opened by one Mechanism opens with proper tools. Not Working maintenance person with proper tools. Bolts cannot be seated. self-locking cover/lid does not work. >--· Cover/lid difficult to One maintenance person cannot remove Cover/lid can be removed and Remove cover/lid after applying 80 lbs. of lift. reinstalled by one maintenance person. 1/9/2009 2009 Surface Water Design Manual -Appendix A A-10 APPENDIX A MAINTENANCE REQUIREMENTS FOR FLOW CONTROL, CONVEYANCE, AND WQ FACILITIES / NO. 6 -CONVEYANCE PIPES AND DITCHES i Maintenance Defect or Problem Conditions When Maintenance is Needed Results Expected When Component Maintenance is Performed Pipes Sediment & debris Accumulated sediment or debris that exceeds Water flows freely through pipes. accumulation 20% of the diameter of the pipe. ----, Vegetation/roots Vegetation/roots that reduce free movement of Water flows freely through pipes. water through pipes. Contaminants and Any evidence of contaminants or pollution such Materials removed and disposed of pollution as oil, gasoline, concrete slurries or paint. according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Damage to protective Protective coating is damaged; rust or corrosion Plpe repaired or replaced. coating or corrosion is weakening the structural integrity of any part of pipe. Damaged Any dent that decreases the cross section area of Pipe repaired or replaced. pipe by more than 20% or is determined to have weakened structural integrity of the pipe. Ditches Trash and debris Trash and debris exceeds 1 cubic foot per 1,000 Trash and debris cleared from square feet of ditch and slopes. ditches. Sediment Accumulated sediment that exceeds 20% of the Ditch cleaned/flushed of all sediment accumulation design depth. and debris so that it matches design. Noxious weeds Any noxious or nuisance vegetation which may Noxious and nuisance vegetation constitute a hazard to County personnel or the removed according to applicable public. regulations. No danger of noxious vegetation where County personnel or the public might normally be. Contaminants and Any evidence of contaminants or pollution such Materials removed and disposed of pollution as oil, gasoline, concrete slurries or paint. according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Vegetation Vegetation that reduces free movement of water Water flows freely through ditches. through ditches. Erosion damage to Any erosion obse1,1ed on a ditch slope. Slopes are not eroding. slopes Rock lining out of One layer or less of rock exists above native soil Replace rocks to design standards. place or missing (If area 5 square feet or more, any exposed native Applicable) soil. ' / 2009 Surface Water Design Manual -Appendix A 1/9/2009 A-11 STRICKER CATO MURPHY • ARCHITECTS, P.S. • I 311 First Avenue South, Suite 300 Seattle,Washington 98104 Tel: (206)324-4800 Fax:(206)322-2875 Website: www.scm-arch.com City of Renton Planning Division 1055 S Grady Way Renton, WA 98057 September 9, 2014 Re: Clarification on Number of Employees to be Employed by the Proposed Renton Heritage Apartments Project Address: 207-219 Main Avenue S, Renton, WA Per the Report to the Hearing Examiner for the above-referenced project, the planning staff recommends that the applicant "be required to revise the parking plan to include ... the provision of additional on-site stalls for potential residential/restaurant employees and restaurant patrons in the amount of I 0-20 stalls. Alternatively, the applicant may provide parking off-site, which could be subject to a joint parking requirement. The revised parking plan shall be submitted to and approved by the Current Planning Project Manager prior to building permit approval or construction permit approval, whichever comes.first." We erroneously indicated that the project will be employing 25 new employees to operate 3,579 square feet of retail space and manage 101 residential units. We would like to clarify that this number is an overestimation on our part, and that the correct number is more likely to be one to two residential managers, and three new employees for the retail component of the project. We respectfully request the planning staff to reconsider their recommendation on the additional parking requirements in light of this clarification. Thank you. Respectfully, ~RB, LEED AP urphy Architects Address ~II I' A,e Sourh. Suitt .<00, Seattle. Washin1"ton 98104 lei (206)324-4800 Fax (206)32~-2875 w11·w.scm arch.com September 9, 2014 Ms Roca le Timmons Senior Planner TD ~ 'Pt.X-€.D t ,-) Fi\:c~. ~(4- aooct-s3 City of Renton -Current Planning 1055 South Grady Way Renton, WA 98057 Re: Renton Heritage Apartments File# LUA14-00933, CU·H, SA-H, MOD Dear Ms Rocale: We are in receipt of the City's recommendations to the Hearing Examiner for our Renton Heritage Apartments. Below please find our response to those recommendations. We have itemized our response numbers to coincide with the numbered items in your recommendations starting on page 29 of the City's report. 1. Agreed. 2. Agreed. 3. Agreed. 4. Parking Comments a. Three northern stalls along alley will be limited to back in parking only. b. A requirement to add 10-20 parking stalls from the currently proposed 101 to address employee parking, retail parking, and added tenant parking is of concern for the following reasons: i. Total project retail is 3,553 Gross SF (may be one or two tenant spaces). Potential employees will be 2-4 maximum. See attached clarification letter from Stricker Cato Murphy Architects. 1. There is no code requirement for Retail Parking. 2. Retail and Residential users have different use times. Retail parking users and employees can be allocated some or all of the 15 spaces outside of the building garage along the alley. These are swing spaces to be utilized by both Retail and Residential Tenants. Use of these spaces will be monitored and managed by residential management firm. ii. Total number of employees managing the project will be 1-2 iii. Residential Tenant parking requirement is one parking space per unit. iv. Adequate off street parking exists in downtown for retail users. v. Transit Center is located a couple of blocks from the project. vi. Urban Jurisdictions across the Puget Sound area are reducing their residential tenant parking requirements: 1. Seattle has no parking requirements. 2. We are current working on a major project in downtown Redmond that is proposing .75 parking spaces per residential unit do to its proximity with a Metro Bus Transit Center. vii. Applicant will add plus or minus 10 additional spaces of in line and/or tandem to Cosmos Development Company increase OVerall parking COUnt in garage tO approximately 111 parking Spaces. Hellevue. NA !Jo·,,_:~, f-'hons ~1'~'4'.il-O'Bt ~AX ~.2i!.'4':,1-84clcl 5. Agreed. 6. Agreed. 7. Agreed. Preliminary elevations are attached to depict general design concept. 8. Agreed. 9. Agreed. 10. Agreed. Additional Streetscape Amenities will be proposed and will include bike racks, trash, containers, and/or benches. These ornamental combinations will be offset by a reduction in interior bike rack requirements to defray the added costs of the ornamental combinations. Formula to be agreed-upon. 11. Agreed. See item 7. 12. Agreed. 13. Agreed. 14. Agreed. See item 10. 15. Agreed. 16. Agreed. 17. Agreed. Thank you for the opportunity to provide comments on the City's Recommendations to the Hearing Examiner for our Renton Heritage Apartments. We look forward to continuing our good working relationship with the City and to the construction of this exiting downtown project. R~pectfully £J j /If (/;---.--(!'--"( /~-- Oscar Del Moro Executive VP Cosmos Development Company