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HomeMy WebLinkAboutEx07_Geotechnical_ReportJob No. 2020-2 S&EE S&EE REPORT OF GEOTECHNICAL STUDY (DRAFT) APRON A-SITE STORMWATER IMPROVEMENTS RENTON MUNICIPAL AIRPORT S&EE JOB NO. 2020-2 MARCH 20, 2020 RECEIVED 04/16/2020 amorganroth PLANNING DIVISION Exhibit 7 DocuSign Envelope ID: AD7CAF2A-ED12-4A88-ACD2-89EFB0E3A881 DocuSign Envelope ID: AD7CAF2A-ED12-4A88-ACD2-89EFB0E3A881 2020-2rpt S&EE TABLE OF CONTENTS Section Page 1.0 INTRODUCTION ................................................................................................................................................. 1 2.0 SCOPE OF WORK ............................................................................................................................................... 2 3.0 SITE CONDITIONS ............................................................................................................................................. 2 3.1 SITE HISTORY & GEOLOGY .......................................................................................................................... 2 3.2 SURFACE CONDITIONS ................................................................................................................................... 3 3.3 SUBSURFACE CONDITIONS ........................................................................................................................... 3 3.4 GROUNDWATER CONDITIONS .................................................................................................................... 4 4.0 LABORATORY TESTING ................................................................................................................................. 4 5.0 ENGINEERING EVALUATIONS AND RECOMMENDATIONS ................................................................. 5 5.1 FOUNDATION SUPPORT ................................................................................................................................ 5 5.1.1 SPREAD FOOTING DESIGN ...................................................................................................................... 5 5.1.2 FOOTING CONSTRUCTION ..................................................................................................................... 5 5.2 SLAB-ON-GRADE OR LOAD-SUPPORTING MATS ................................................................................... 6 5.3 UNDERGROUND UTILITY CONSTRUCTION .............................................................................................. 6 5.3.1 TEMPORARY SLOPE AND SHORING ...................................................................................................... 6 5.3.2 SUBGRADE PREPARATION ..................................................................................................................... 7 5.3.3 BEARING CAPACITY AND SUBGRADE MODULUS .............................................................................. 7 5.3.4 DEWATERING .......................................................................................................................................... 7 5.3.5 BUOYANCY RESISTANCE ...................................................................................................................... 8 5.4 STRUCTURAL FILL ......................................................................................................................................... 8 5.5 LATERAL EARTH PRESSURES ON PERMANENT UNDERGROUND WALLS ........................................ 9 5.6 PAVEMENT RECOMMENDATIONS ............................................................................................................ 10 5.7 SEISMIC CONSIDERATION AND HAZARDS ............................................................................................ 11 5.8 ADDITIONAL SERVICES .............................................................................................................................. 12 6.0 CLOSURE ............................................................................................................................................................. 12 FIGURE 1: SITE LOCATION MAP FIGURE 2: LOCATION OF PREVIOUS BORINGS (APRON A NORTH) FIGURE 3: MAP SHOWS PREVIOUS LAKE SHORELINE FIGURE 4: LIQUIFACTION MAP APPENDIX A: FIELD EXPLORATION AND LOG OF BORING APPENDIX B: LABORATORY TEST RESULTS DocuSign Envelope ID: AD7CAF2A-ED12-4A88-ACD2-89EFB0E3A881 1508rpt S&EE (DRAFT) REPORT OF GEOTECHNICAL STUDY APRON A-SITE STORMWATER IMPROVEMENTS For The Boeing Company 1.0 INTRODUCTION We present in this report our geotechnical study for the proposed Apron A-Site Stormwater Improvements project at Renton Municipal Airport. The project site is located in the eastern portion of the airport. A Site Location Map is shown in Figure 1 which is included at the end this report. At the time of this report, we are preparing a field exploration and testing program. The program will include the drilling of a few soil test borings, characteristic testing of soil samples for geotechnical properties, as well as analytical testing of soil and groundwater samples for environmental profiles. The results of the field exploration and testing program will be included in a final report which will be issued at a later date. This draft report utilizes the geotechnical data we collected at Apron A North which is adjacent to the current site. Based on our knowledge of the site area, we believe that the subsurface conditions in the area are relatively consistent. We will evaluate the results of the planned field exploration and testing program, and make modifications to our recommendations, if necessary. We understand that the project scope will include the followings. I) The conveyance system, water quality and fuel spill containment systems to capture and treat the runoff from the eastern quarter of stalls A3-A7. The proposed improvements include the installation of approximately 810 LF of slot drain, catch basins, HDPE storm drainage pipe, an oil water separator, enhanced water quality treatment, connection to the existing A7 stall drainage, and replacement and upgrades to the existing fuel spill valves and controls within stall A7. II) The conveyance and water quality systems to capture the runoff from the W1 parking lot. The proposed improvements include the installation of approximately 9 separate Modular Wetland water quality units along with a conveyance system for the treated water and connection to the existing W1 parking lot outfall. The depth of the utility lines will range from 3 to 7 feet and the depths of the vaults and catch basins will range from 7 to 10 feet. DocuSign Envelope ID: AD7CAF2A-ED12-4A88-ACD2-89EFB0E3A881 2020-2rpt 2 S&EE 2.0 SCOPE OF WORK The purpose of our geotechnical study is to provide geotechnical parameters and recommendations for design and construction. Specifically, the scope of our services includes the following: 1. Review of available geotechnical data. A field exploration program was performed at Apron A North which is immediately north of the current project site. A total of 10 soil test borings were performed in 2015. The locations of these borings are shown in Figure 2 and the log of borings are included in Appendix A. 2. Engineering evaluations and recommendation for the following: - Foundation support - Excavation shoring and dewatering - Pavement design - Underground utility design and construction - Earthwork 3. Meetings and communications 4. Preparation of this geotechnical report 5. Preparation of a field exploration and testing program. 3.0 SITE CONDITIONS 3.1 SITE HISTORY & GEOLOGY Renton Municipal Airport is located at the south end of Lake Washington. Figure 3 shows that the northern portion of the airport was once under the lake. The Black River used to run out of the lake, flowed south through the site vicinity and then veered west. In 1911, Cedar River flooded Renton. In the following year the town excavated a 2000-foot-long, 80-foot-wide canal to reroute the course of the river to the north so that it flowed directly into Lake Washington, in the hope of avoiding floods in the future. From July to October 1916, the construction of the Lake Washington Ship Canal lowered Lake Washington 8.8 feet. In the process, the Black River dried up, and the outfall DocuSign Envelope ID: AD7CAF2A-ED12-4A88-ACD2-89EFB0E3A881 2020-2rpt 3 S&EE from Lake Washington became the ship canal (reference: Suzanne Larson, History of the Lake Washington Ship Canal, King County Arts Commission, 1975, Introduction, 23.) During WW II, the site area was leveled by up to 8 feet thick of fill. The native soils immediately under the fill include alluvial deposits that are over 100 feet in thickness. These soils are typically soft and unconsolidated in the upper 50 feet and become compact thereafter. Published geologic information (Geologic Map of The Renton Quadrangle, King County, Washington by D.R. Mullineaux, 1965) indicates that the alluvial soils are underlain by Arkosic sandstone. S&EE performed a few soil test borings in 2012 – 2013 at North Bridge site located at the north end of Cedar River (see Figure 3). These borings found glacially deposited and consolidated soil (hard silt) at depths of about 150 to 170 feet. Boring data from our previous projects at the south side of Renton Airport show that the hard silt is underlain by sandstone. Seismic Hazards The project site is under the threat of the movement of the Seattle Fault. This fault is a collective term for a series of four or more east-west-trending, south-dipping fault strands underlying the Seattle area. This thrust fault zone is approximately 2 to 4 miles wide (north-south) and extends from the Kitsap Peninsula near Bremerton on the west to the Sammamish Plateau east of Lake Sammamish on the east. The four fault strands have been interpolated from over-water geophysical surveys (Johnson, et al., 1999) and, consequently, the exact locations on land have yet to be determined or verified. Recent geologic evidence suggests that movement on this fault zone occurred about 1,100 years ago, and the earthquake it produced was on the order of a magnitude 7.5. 3.2 SURFACE CONDITIONS The project site is bordered by airport runway to the west and Perimeter Road to the east. The road runs along the top of the levy that borders Cedar River. The northern boundary of the site borders the taxiway that connects the South Bridge. The majority of Apron “A” is covered with concrete and asphalt pavements. The pavement is in fair conditions. There are some small cracks but no obvious signs of distress. The site surface is very flat. 3.3 SUBSURFACE CONDITIONS As mentioned previously, we believe that the subsurface conditions at the current project site are similar to those at the neighboring Apron A North. This assumption will be confirmed by the DocuSign Envelope ID: AD7CAF2A-ED12-4A88-ACD2-89EFB0E3A881 2020-2rpt 4 S&EE planned field exploration program. Based on the boring data obtained at the Apron A North site, the subsurface conditions in the site area include fill over native soils. The fill ranges from about 3 to 8 feet in thickness and includes sand, silty sand and silt. In general, these soils are at least medium dense or medium stiff in the upper 5 feet and appear to have been placed with some compaction. The native soils below the fill include sand, silty sand and silt. In general, these soils are very loose to loose or very soft to soft. Based on our knowledge of the subsurface conditions in the region, we believe that these soils are underlain by glacially deposited soils a depth of about 150 to 170 feet. 3.4 GROUNDWATER CONDITIONS Based on our experience with the subsurface conditions in the site vicinity, we believe that the depth of groundwater is affected by the river level and precipitation. We expect that the groundwater may vary between 4 to 7 feet below the ground surface. The groundwater depth will fluctuate with season and precipitation. In general, the depth will be the lowest in summer and highest in winter. 4.0 LABORATORY TESTING A laboratory consolidation test was performed in the previous investigation for Apron A North. The test results are included in Appendix B and were utilized in the current study. DocuSign Envelope ID: AD7CAF2A-ED12-4A88-ACD2-89EFB0E3A881 2020-2rpt 5 S&EE 5.0 ENGINEERING EVALUATIONS AND RECOMMENDATIONS 5.1 FOUNDATION SUPPORT 5.1.1 SPREAD FOOTING DESIGN We recommend that conventional spread footings be utilized for the support of light-weight structures. The footings can be designed with an allowable bearing load of 1,500 pounds per square feet (psf). This value includes a safety factor of at least 3, and can be increased by one-third for wind and seismic loads (no increase for blast loads). Based on our estimate, short-term (less than a month) settlement should be about 1/2 inch, and long-term settlement should be about one inch. Lateral Resistance: Lateral resistance can be obtained from the passive earth pressure against the footing sides and the friction at the contact of the footing bottom and base course. The former can be obtained using an equivalent fluid density of 230 pounds per cubic feet (pcf), and the latter using a coefficient of friction of 0.5. These values include a safety factor of 1.5. 5.1.2 FOOTING CONSTRUCTION We recommend that footing subgrades be inspected by our site inspector. In the event that soft, wet or organic soils are present at or near subgrade level, we will provide recommendations regarding over-excavation and/or other method of subgrade stabilization such as the use of geotextile. The contractor should prepare to compact the subgrade with a compactor that weighs at least 800 pounds. The subgrade soil should have adequate moisture content (within +/-2% from optimum) at the time of compaction. A 6-inch thick crushed rock layer should be installed at the bottom of the footing. The crushed rock should have an adequate moisture content (+/- 2% from optimum) at the time of placement, and be compacted to a firm and non-yielding condition using the same compactor. Exterior footings should be founded at least 15 inches below the adjacent finished grade to provide protection against frost action. In the event that thickened-edges are to be constructed, the slope connecting the slab and footing should be 2H:1V or flatter. The flat slope is to prevent subgrade disturbance during rebar installation. DocuSign Envelope ID: AD7CAF2A-ED12-4A88-ACD2-89EFB0E3A881 2020-2rpt 6 S&EE 5.2 SLAB-ON-GRADE AND LOAD-SUPPORTING MATS Slab-on-grade and load-supporting mats can be designed using a subgrade reaction modulus of 100 pounds per cubic inches (pci). Similar to footing subgrade preparation, all slabs and mats should be underlain by a 6-inch thick crushed rock layer. The crushed rock should have an adequate moisture content (+/- 2% from optimum) at the time of placement, and be compacted to a firm and non-yielding condition using a compactor that weighs at least 800 pounds. Again, if thickened edges are to be installed, the slope between the slab and thickened edges should be 2H:1V or flatter. 5.3 UNDERGROUND UTILITY CONSTRUCTION 5.3.1 TEMPORARY SLOPE AND SHORING When temporary excavations are required during construction, the contractor should be responsible for the safety of their personnel and equipment. The followings cut angles are provided only as a general reference: Open cuts shallower than 3 feet may be cut vertically. For cuts over 3 feet and shallower than 5 feet, the cut should be sloped at 1H:1V or flatter. Cuts over 5 feet in depth or below groundwater table may need to be 2H:1V or flatter. For a combination of open cut and shoring, benching in the upper 2 to 4 feet works well in the past as it lessens the overburden pressure and facilitates backfill. The benches should have a 1:1 ratio for bench height and width. To avoid bank caving, the height of each bench should be limited to 2 feet. Excavation shoring will be required at locations of space constraint. A variety of shoring methods has been used at Boeing Renton Plant, including trench boxes, steel sheets, timber lagging, and steel sheetpile. For estimating purposes, we recommend the following soil parameters for the design. We should review the design and provide recommendations for necessary adjustments. • Soil’s total unit weight: 130 pcf (pounds per cubic feet) • Soil’s buoyant unit weight: 60 pcf • Active soil pressure: 45 pcf, equivalent fluid density, above groundwater table • Active soil pressure: 21 pcf, equivalent fluid density, below groundwater table • Passive soil pressure: 190 pcf, equivalent fluid density, above groundwater table (include 1.5 safety factor) • Passive soil pressure: 80 pcf, equivalent fluid density, below groundwater table (include 1.5 safety factor) Please note that unbalanced hydrostatic pressure should be added to the active side. A 2 feet over- excavation at the passive side should be considered in the design. DocuSign Envelope ID: AD7CAF2A-ED12-4A88-ACD2-89EFB0E3A881 2020-2rpt 7 S&EE 5.3.2 SUBGRADE PREPARATION All loose soil cuttings should be removed prior to the placement of bedding materials. Wet and loose subgrades should be anticipated. The contractor should make efforts to minimize subgrade disturbance, especially during the last foot of excavation. Subgrade disturbance in wet and loose soil may be inevitable and stabilization is necessary in order to avoid re-consolidation of the disturbed zone. Depending on the degrees of disturbance, the stabilization may require a layer of quarry spalls (2 to 4 inches or 4 to 6 inches size crushed rock). Based on our experience at Apron A North, when compacted by a hoepac, a 12 to 18 inches thick layer of spalls would sink into the loose and soft subgrade, interlock and eventually form a stable subbase. A chocker stone such as 1-1/4-inch or 5/8- inch clean (no fines) crushed rock should be installed over the quarry spalls. This stone should be at least 4 inches in thickness and should be compacted to a firm and non-yielding condition by a jumping jack compactor or a vibratory plate compactor that weighs at least 800 pounds. In the event that soft silty soils above groundwater table are encountered at subgrades, the subgrade should be over-excavated for a minimum of 6 inches. A non-woven geotextile having a minimum grab tensile strength of 200 pounds should be installed at the bottom of the over-excavation and the over-excavation be backfilled with 1-1/4” minus crushed rock. The material should be compacted to a firm a non-yielding condition by the same compactors. 5.3.3 BEARING CAPACITY AND SUBGRADE MODULUS Subgrade so prepared should have an allowable bearing capacity of 1,500 psf (pounds per square feet), and a subgrade modulus of 50 pci (pounds per cubic inches). The bearing capacity includes a safety factor of 3. Total settlement under these loads should be on the order of 1/4 to 1/2 inch. 5.3.4 D EWATERING Dewatering will be required for excavations deeper than the groundwater table. One groundwater monitoring well is planned in the proposed field exploration program. Since the depth of groundwater will fluctuate with seasons and precipitation, we recommend that the contractor measure the depth prior to excavation. Based on our experience at Apron A North, dewatering can be successful using local sumps for excavations shallower than 5 feet in the winter months and 8 feet in the summer months. The contractor should install sumps at locations and spacing that are best fitted for the situation. To facilitate drainage, the sump holes should be at least 2 feet below the DocuSign Envelope ID: AD7CAF2A-ED12-4A88-ACD2-89EFB0E3A881 2020-2rpt 8 S&EE excavation subgrade. Also, the granular backfill in the sump should allow hydraulic connection with the crushed rock and quarry spalls placed for subgrade stabilization. Well-points can be considered for the dewatering of deeper excavations. A detailed well-point design is typically provided by a hydrogeologist. O ur experience at Apron A North has shown that well-points at 5 to 8 feet spacing can provide adequate dewatering. The discharge rates may range from1/2 to 5 gallons per minutes per well-point. 5.3.5 BUOYANCY RESISTANCE The subsoils below groundwater table will liquefy during strong earthquakes. As such, buoyancy force should be considered in the design. If the self-weight of the structure and equipment is insufficient to resist the buoyancy force, an extended base can be considered for additional resistance. In this case, the additional resistance can be calculated using the weight of the soil above groundwater table and above the extended base. A soil’s unit weight of 13 0 pounds per cubic feet (pcf) can be used for this purpose. Sidewall friction should be ignored. 5.4 STRUCTURAL FILL Structural fill should be used for utility backfill and in areas that will support loads such as slab, pavement, walkway, etc. Structural fill materials should meet both the material and compaction requirements presented below. Material Requirements: Structural fill should be free of organic and frozen material and should consist of hard durable particles, such as sand, gravel, or quarry-processed stone. The existing onsite fill soils are suitable on a selective basis; and its suitability should be confirmed by a site inspector from our office. The soil below groundwater table are not suitable for structural fill. Suitable imported structural fill materials include silty sand, sand, mixture of sand and gravel (pitrun), recycle concrete, and crushed rock. All structural fill materials should be approved by an engineer from our office prior to use. Please note that: - Flowable CDF (Control Density Fill) is an acceptable structural fill. The following recommendations should be followed: 1) CDF should have a minimum compressive strength of 150 psi. 2) All loose/disturbed subgrade soils should be removed prior to CDF DocuSign Envelope ID: AD7CAF2A-ED12-4A88-ACD2-89EFB0E3A881 2020-2rpt 9 S&EE pour; and 3) shoring should be retrieved while CDF is still fluid so that all voids around shoring will be filled. - Recycled concrete often has a fines content exceeding 20%, making the material sensitive to moisture. As such, the material may be difficult to use in wet winter month Placement and Compaction Requirements: Structural fill should be placed in loose horizontal lifts not exceeding a thickness of 6 to 12 inches, depending on the material type, compaction equipment, and number of passes made by the equipment. Structural fill should be compacted to a firm and non-yielding condition. The subsoils at the site are soft and loose, and groundwater is shallow. Therefore, compaction requirements using conventional method such as 95% Proctor may not be suitable for the project site, as this may lead to disturbance to the subgrade soils and uneven settlement of the underground utilities. We thus recommend performance base requirements including appropriate compaction equipment, moisture content, lift thickness, number of passes, and inspection/approval by our onsite inspector. 5.5 LATERAL EARTH PRESSURES ON PERMANENT UNDERGROUND WALLS Lateral earth pressures on permanent retaining walls, underground vaults or utility trenches/pits, and resistance to lateral loads may be estimated using the recommended soil parameters presented in the following table. Equivalent Fluid Unit Weight (PCF) Coefficient of Friction at Base Active At-rest Passive Structural fill and native soils 45 60 250 0.4 Note: Hydrostatic pressures are not included in the above lateral earth pressures. DocuSign Envelope ID: AD7CAF2A-ED12-4A88-ACD2-89EFB0E3A881 2020-2rpt 10 S&EE The at-rest case applies to unyielding walls, and would be appropriate for walls that are structurally restrained from lateral deflection such as basement walls, utility trenches or pits. The active case applies to walls that are permitted to rotate or translate away from the retained soil by approximately 0.002H to 0.004H, where H is the height of the wall. The passive earth pressure and coefficient of friction include a safety factor of 1.5. SURCHARGE INDUCED LATERAL LOADS Additional lateral earth pressures will result from surcharge loads from floor slabs or pavements for parking that are located immediately adjacent to the walls. The surcharge-induced lateral earth pressures are uniform over the depth of the wall. Surcharge-induced lateral pressures for the "active" case may be calculated by multiplying the applied vertical pressure (in psf) by the active earth pressure coefficient (Ka). The value of Ka may be taken as 0.36. The surcharge-induced lateral pressures for the "at-rest" case are similarly calculated using an at-rest earth pressure coefficient (Ko) of 0.5. 5.6 PAVEMENT RECOMMENDATIONS We recommend that all pavement subgrades be proof-rolled to identify areas of soft, wet, organic, or unstable soils. Proof-rolling should be accomplished with a heavy (10-ton) vibratory roller, front-end- loader, or loaded dump truck (or equivalent) making systematic passes over the subgrade while being observed by a site inspector from our office. In areas where unstable and/or unsuitable subgrade soils are observed, these soils should be over-excavated a minimum 12 inches. Additional over-excavation depth may be required to remove buried debris, organic or very soft soil. Woven geotextile having a minimum 200 pounds grab tensile strength may be necessary for additional subgrade stabilization. The geotextile should be placed with 12-inch overlaps and all wrinkles removed. The over-excavation should be monitored by an inspector from our office. Our inspector will provide recommendations regarding the final depth of over-excavation and the preparation of the over-excavated subgrade. The over-excavation should then be backfilled with structural fill. The material should have adequate moisture content, and be compacted to a firm and non-yielding condition by a compactor approved by our site inspector. After proof-rolling, the top 12 inches of the subgrade should be thoroughly compacted to a firm and non- yielding condition. The subgrade soil should have adequate moisture content (within +/-2% from optimum) at the time of compaction. DocuSign Envelope ID: AD7CAF2A-ED12-4A88-ACD2-89EFB0E3A881 2020-2rpt 11 S&EE Asphalt pavements constructed over prepared subgrades can be designed with a CBR (California Bearing Ratio) value of 10; concrete pavement can be designed with a subgrade reaction modulus of 50 pci (pounds per cubic inches). Top course and base courses under pavements should consist of well-graded crushed rock conforming to either FAA requirements or WSDOT specifications for Crushed Surfacing, Specification 9-03.9(3). The material should be compacted to at least 95 percent of the maximum dry density, as determined by the modified Proctor compaction test (ASTM D 1557) or to meet standards dictated by project specifications. 5.7 SEISMIC CONSIDERATION AND HAZARDS We have evaluated the geotechnical-related parameters for seismic design in accordance with 2015 IBC. The spectral response accelerations for the “Risk-Targeted Maximum Considered Earthquake” (MCER) were obtained from the USGS website using a latitude of 47.493 degrees and a longitude of 122.216 degrees. The values for Site Class B (rock) are: SS = 1.455 g (short period, or 0.2 second spectral response) S1 = 0.545 g (long period, or 1.0 second spectral response) The Site Class is selected using the definitions in Chapter 20 of ASCE 7-10 considering the average properties of soils in the upper 100 feet of the soil profile at the site. Using the boring data obtained from current and previous projects, we estimate that the average standard penetration resistance (N) in the upper 100 feet is 7. This value corresponds to Site Class E (“Soft Clay Soil”) in Table 20.3-1 (ASCE 7- 10). The site coefficient values are used to adjust the mapped spectral response acceleration values to get the adjusted spectral response acceleration values for the site. The recommended Site Coefficient values for Site Class E are: Fa = 0.9 (short period, or 0.2 second spectral response) Fv = 2.4 (1.0 second spectral response) The most recent USGS Earthquake Hazards Map (U.S. Geologic Survey web site, 2008 data) has indicated that a horizontal peak acceleration (PGA) of 0.61 g is appropriate for a 4275-year return period event, i.e. an event having a 2 percent chance of being exceeded in 50 years. DocuSign Envelope ID: AD7CAF2A-ED12-4A88-ACD2-89EFB0E3A881 2020-2rpt 12 S&EE Based on our evaluation, the subsoils below the groundwater table and to a depth of about 100 feet are liquefaction prone during the subduction zone earthquakes. Also, liquefaction can result in ground settlements on the order of 10 to 20 inches. 5.8 ADDITIONAL SERVICES We recommend the following additional services during the construction of the project: 1. Monitor underground utility construction. We will observe excavation and recommend re-use of onsite soil for backfill; observe excavation subgrade and provide recommendations regarding subgrade stabilization; observe dewatering and provide recommendations when necessary; observe any potential adverse impacts on nearby structures and provide recommendations regarding mitigation; observe backfill placement and assist contractor to achieve compaction. 2. Monitor footing and mat constructions. We will observe subgrades and approve bearing capacity; provide recommendations regarding subgrade stabilization, if necessary. 3. Monitor pavement construction. We will observe proof-rolling and provide recommendations regarding local over-excavation to remove soft, wet or organic soil; observe and approve structural fill material and base course; observe and approve fill placement and assist contractor to achieve compaction. 4. Review contractors’ submittals and RFI’s. 5. Attend construction progress meetings. 6. Prepare and distribute field reports. 7. Other geotechnical issues deemed necessary. 6.0 CLOSURE The recommendations presented in this report are provided for design purposes and are based on soil conditions disclosed by the available geotechnical boring data. Subsurface information presented herein does not constitute a direct or implied warranty that the soil conditions between exploration locations can be directly interpolated or extrapolated or that subsurface conditions and soil variations different from those disclosed by the explorations will not be revealed. The recommendations outlined in this report are based on the assumption that the development plan is consistent with the description provided in this report. If the development plan is changed or subsurface conditions different from those disclosed by the exploration are observed during construction, we should be advised at once so that we can review these conditions, and if necessary, reconsider our design recommendations. DocuSign Envelope ID: AD7CAF2A-ED12-4A88-ACD2-89EFB0E3A881 LOGAN AVEEXIT 5 900 515 900 EXIT 4 EXIT 4A 405 405 167 EXIT 4B 405 169 167 D9 D40 D35 D30 EXIT 2B From Issaquah From Bellevue 4-04 Medical Clinic Safety LK WASHINGTON BLVD N From Seattle LAKE WASHINGTON Boeing Employees Flying Association RA I N I E R A V E N 4-41 4-20 4-21 4-69 4-402 4-78 4-77 4-79 4-71 4-42 4-45 Apron D 5-27 5-403 5-288 9 7 1 16 17 15 12 13A 14 10-18 GARDEN AVE N N EVA NEDRAGEVA KRAPN 8TH ST 11 10-16 10-13 4-89 4-88Badge Office 10-20 10-80 Hub 4-17 4-90 4-75 4-81 4-82 4-83 4-86 Renton Airport From I-5 From Longacres Park From Kent and Auburn From Enumclaw Apron A Apron BRAINIER AVE N AIRPORT WAY RE N T O N A V E S S 3RD ST S 2ND ST Renton Stadium 5-09 5-02 S U N S E T B L V D W BENSON RD S M. L . K I N G J R W A Y S SW 10TH S T OAKESDALE AVE SW SW 19TH ST SW 16TH ST DNOMYAR WS EVA WS EVA DNILTALBOT RD S EVA NIAM HOUSER WAY N LOGAN AVE N CEDAR RIVER N 1 S T S T BRONSON W AY N S 4TH ST N 3RD ST N 4TH ST N NEDRAG S EVA TTENRUBLOGAN AVE S SW 7TH ST GRADY WA Y S W N EVA YROTCAFMONSTER RD 5-50 5-51 N EVA SMAILLIW7-206 Triton Tower Two 7-207 Triton Tower Three From Seattle 5-08 Washington – Renton North 8th and Park Avenue North, Renton, WA 98055 N 5TH ST N 6TH ST N 8TH ST 5-45 Revised 03-09 Boeing North Bridge Boeing South Bridge 7-244 Rivertech Corporate Center HOUSER WAY BYPASS Copyright 2009© The Boeing Company. All rights reserved.PARK AVE N WELLS AVE N POWELL AVE SW NACHES AVE 4-95Shed 4-96GuardShack Employee gates AMS Turnstile gates Fence lines Boeing property General parking Restricted parking Bus stop Helistop 51 52 53 54 55 51 52 53 54 55 A B C D E F A B D E F C D44 D41 D4 D32CURRENT SITE Figure 1 - Site Location Map APRON A-NORTH DocuSign Envelope ID: AD7CAF2A-ED12-4A88-ACD2-89EFB0E3A881 B-3AB-3B with Groundwater Monitoring WellB-4B-5Figure 2 - Site & Exploration Plan (Sep-14-2015 Revision)NB-1 B-2 B-6B-7B-8B-9B-10APRON A NORTH UPGRADE (Completed 2016)CURREN/PROPOSED APRON A-SITE STORMWATER IMPROVEMENTSSOUTH BRIDGEDocuSign Envelope ID: AD7CAF2A-ED12-4A88-ACD2-89EFB0E3A881 RentonFacilityBoundary AncestralCedarRiver AncestralBlackRiver Former LakeWashingtonShoreline CurrentCedar RiverWaterway 01-0183 Fig2-9.ai R DESIGNERS/CONSULTANTSMANAGERS N Scale in Feet 0 500 1000 Figure Renton Airport Former Lake Washington Shoreline, Black and Cedar River Channels 2-9 Wetland Forested Uplands EXPLANATION Facility Boundary Former Lake Washington Shoreline Ancestral Black River Ancestral Cedar River Current Cedar River Waterway Geologic Cross Section (see figure 2-8)A A' A' A Figure 3 Approximate Location of Project Site North Bridge DocuSign Envelope ID: AD7CAF2A-ED12-4A88-ACD2-89EFB0E3A881 Figure 4 (Airport) DocuSign Envelope ID: AD7CAF2A-ED12-4A88-ACD2-89EFB0E3A881 2020-2rpt S&EE APPENDIX A FIELD EXPLORATION AND LOG OF BORING The subsurface conditions at the neighboring project site were explored with the drilling of 10 soil test borings, B-1 to B-10 on September 17 and 18, 2015. The test boring was advanced using a truck- mounted drill rig. Boring B-3A encountered an abandoned storm drain at a depth of 9 feet. The boring was moved 2 feet northwest and a new boring, B-3B, was drilled. A representative from S&EE was present throughout the exploration to observe the drilling operations, log subsurface soil conditions, obtain soil samples, and to prepare descriptive geologic logs of the exploration. Soil samples were taken at 2.5- and 5-foot intervals in general accordance with ASTM D-1586, "Standard Method for Penetration Test and Split-Barrel Sampling of Soils" (1.4” I.D. sampler). The penetration test involves driving the samplers 18 inches into the ground at the bottom of the borehole with a 140 pounds hammer dropping 30 inches. The numbers of blows needed for the samplers to penetrate each 6 inches are recorded and are presented on the boring logs. The sum of the number of blows required for the second and third 6 inches of penetration is termed "standard penetration resistance" or the "N- value". In cases where 50 blows are insufficient to advance it through a 6 inches interval the penetration after 50 blows is recorded. The blow count provides an indication of the density of the subsoil, and it is used in many empirical geotechnical engineering formulae. The following table provides a general correlation of blow count with density and consistency. DENSITY (GRANULAR SOILS) CONSISTENCY (FINE-GRAINED SOILS) N-value < 4 very loose N-value < 2 very soft 5-10 loose 3-4 soft 11-30 medium dense 5-8 medium stiff 31-50 dense 9-15 stiff >50 very dense 16-30 very stiff >30 hard After drilling, the test borings were backfilled with bentonite chips and the surface is patched with quick set concrete. The boring logs are included in this appendix. A chart showing the Unified Soil Classification System is included at the end of this appendix. DocuSign Envelope ID: AD7CAF2A-ED12-4A88-ACD2-89EFB0E3A881 DocuSign Envelope ID: AD7CAF2A-ED12-4A88-ACD2-89EFB0E3A881 DocuSign Envelope ID: AD7CAF2A-ED12-4A88-ACD2-89EFB0E3A881 DocuSign Envelope ID: AD7CAF2A-ED12-4A88-ACD2-89EFB0E3A881 DocuSign Envelope ID: AD7CAF2A-ED12-4A88-ACD2-89EFB0E3A881 DocuSign Envelope ID: AD7CAF2A-ED12-4A88-ACD2-89EFB0E3A881 DocuSign Envelope ID: AD7CAF2A-ED12-4A88-ACD2-89EFB0E3A881 DocuSign Envelope ID: AD7CAF2A-ED12-4A88-ACD2-89EFB0E3A881 DocuSign Envelope ID: AD7CAF2A-ED12-4A88-ACD2-89EFB0E3A881 DocuSign Envelope ID: AD7CAF2A-ED12-4A88-ACD2-89EFB0E3A881 DocuSign Envelope ID: AD7CAF2A-ED12-4A88-ACD2-89EFB0E3A881 DocuSign Envelope ID: AD7CAF2A-ED12-4A88-ACD2-89EFB0E3A881 DocuSign Envelope ID: AD7CAF2A-ED12-4A88-ACD2-89EFB0E3A881 DocuSign Envelope ID: AD7CAF2A-ED12-4A88-ACD2-89EFB0E3A881 DocuSign Envelope ID: AD7CAF2A-ED12-4A88-ACD2-89EFB0E3A881 DocuSign Envelope ID: AD7CAF2A-ED12-4A88-ACD2-89EFB0E3A881 DocuSign Envelope ID: AD7CAF2A-ED12-4A88-ACD2-89EFB0E3A881 DocuSign Envelope ID: AD7CAF2A-ED12-4A88-ACD2-89EFB0E3A881 DocuSign Envelope ID: AD7CAF2A-ED12-4A88-ACD2-89EFB0E3A881 Job No. 1509 S&EE APPENDIX B LABORATORY TESTING The soil sample at the depth of 27.5 feet from Boring B-3B was transported to our sub-contracted laboratory, Materials Testing & Consulting, for consolidation testing of a peaty soil. The soil properties were used in the evaluation of consolidation (long-term) settlement. DocuSign Envelope ID: AD7CAF2A-ED12-4A88-ACD2-89EFB0E3A881 Project:Apron - A Project #:15T003-02 Date Received:09/21/15 Client:Soil & Environmental Engine Sampled By:Client Sample Description Source:27.5' Depth Date Tested:09/22/15 Gray Silt with Brown Peat Sample#:T15-0423 Tested By:CL Equipment Used GeoTac Sigma-1 Load Frame 107.7%Final Moisture Content, %55.0% 39.0 Final Dry Unit Weight, lb/ft3 67.9 2.63 Final Void Ratio 1.21 92.8%Final Saturation 99.5% These values are calculated from the initial sample parameters, using a specific gravity of 2.27. Load, psf Strain Ratio D0 D50 D100 Df t90 (min)Sample Ht Drainage Path Cv (in2/s) 500 1.16%0.0000 0.0053 0.0105 0.0104 0.8896 0.4448 1,000 3.24%0.0104 0.0098 0.0300 0.0188 0.81 0.8708 0.4354 0.00341 2,000 6.62%0.0188 0.0212 0.0611 0.0492 0.49 0.8404 0.4202 0.00364 4,000 13.25%0.0492 0.0362 0.1215 0.1089 4.00 0.7807 0.3904 0.00120 8,000 23.34%0.1089 0.0521 0.2130 0.1996 5.29 0.6900 0.3450 0.00071 16,000 30.68%0.1996 0.0404 0.2805 0.2657 4.00 0.6239 0.3119 0.00035 32,000 39.59%0.2657 0.0389 0.3434 0.3459 12.25 0.5437 0.2718 0.00020 64,000 46.22%0.3459 0.0200 0.3859 0.4008 6.76 0.4888 0.2444 0.00015 16,000 45.66% 4,000 42.71% 1,000 37.80% Calculations: The following equation was used to calculate the values shown in the table above: Cv = THD502/t50 Where: T = The time factor for 50% consolidation, provided as 0.197 (per ASTM D2435). HD50 = The length of the drainage path at 50% of primary consolidation (double drainage path). t50 = The time corresponding to 50% of primary consolidation. For the void ratio and saturation values, an assumed specific gravity of 2.65 was used. Comments: Regional Offices: Olympia ~ 360.534.9777 Bellingham ~ 360.647.6111 Silverdale ~ 360.698.6787 Tukwila ~ 206.241.1974 Visit our website: www.mtc-inc.net Corporate ~ 777 Chrysler Drive • Burlington, WA 98233 • Phone (360) 755-1990 • Fax (360) 755-1980 Sample Parameters Test Data Reviewed by: Initial Moisture Content, % Initial Dry Unit Weight, lb/ft3 Initial Void Ratio Initial Saturation All results apply only to actual locations and materials tested. As a mutual protection to clients, the public and ourselves, all reports are submitted as the confidential property of clients, and authorization for publication of statements, conclusions or extracts from or regarding our reports is reserved pending our written approval. Materials Testing & Consulting, Inc. Geotechnical Engineering • Special Inspection • Materials Testing • Environmental Consulting One-Dimensional Consolidation Report One-Dimensional Consolidation performed in accordance with ASTM D2435/D2435M DocuSign Envelope ID: AD7CAF2A-ED12-4A88-ACD2-89EFB0E3A881 Project:Apron - A Project #:15T003-02 Date Received:09/21/15 Client:Soil & Environmental Engineers Sampled By:Client Sample Description Source:27.5' Depth Date Tested:09/22/15 Gray Silt with Brown PeatSample#:T15-0423 Tested By:CL Equipment Used GeoTac Sigma-1 Load Frame Step No.Vertical Stress (psf) Vertical Strain (%) D90 (in) D100 (in) H100 (in) H50 (in) t90 (min) cv (in2/sec) 1 500 1.16 0.0000 0.8896 0.0000 N/A 2 1000 3.24 0.0108 0.0120 0.8708 0.8836 0.81 0.00341 3 2000 6.62 0.0160 0.0180 0.8404 0.8628 0.72 0.00364 4 4000 13.25 0.0380 0.0412 0.7807 0.8153 1.96 0.00120 5 8000 23.34 0.0520 0.0573 0.6900 0.7500 2.79 0.00071 6 16000 30.68 0.0450 0.0500 0.6239 0.6650 4.41 0.00035 7 32000 39.59 0.0440 0.0487 0.5437 0.5985 6.25 0.00020 8 64000 46.22 0.0360 0.0397 0.4888 0.5224 6.25 0.00015 Comments: Reviewed by: -0.0020 0.0000 0.0060 0.0251 0.0307 0.0250 0.0253 0.02130.0030 0.0020 0.0000 0.0040 0.0090 Regional Offices: Olympia ~ 360.534.9777 Bellingham ~ 360.647.6111 Silverdale ~ 360.698.6787 Tukwila ~ 206.241.1974 Visit our website: www.mtc-inc.net Corporate ~ 777 Chrysler Drive • Burlington, WA 98233 • Phone (360) 755-1990 • Fax (360) 755-1980 All results apply only to actual locations and materials tested. As a mutual protection to clients, the public and ourselves, all reports are submitted as the confidential property of clients, and authorization for publication of statements, conclusions or extracts from or regarding our reports is reserved pending our written approval. D0 (in) D50 (in) 0.0080 0.0000 Materials Testing & Consulting, Inc. Geotechnical Engineering • Special Inspection • Materials Testing • Environmental Consulting One-Dimensional Consolidation Report One-Dimensional Consolidation performed in accordance with ASTM D2435/D2435M Sample Preparation Natural Moisture Test Method Used Data Interpretation Procedure Procedure 2 (SqRt) Procedure 1 (Log) 0.00 5.00 10.00 15.00 20.00 25.00 30.00 35.00 40.00 45.00 50.00 100 1,000 10,000 100,000Axial Strain (%) Axial Effective Stress (psf) Axial Strain versus Axial Effective Stress Consolidation Test Results at the End of Incremental Loading Method A Inundated Method B DocuSign Envelope ID: AD7CAF2A-ED12-4A88-ACD2-89EFB0E3A881 Project:Apron - A Project #:15T003-02 Date Received:09/21/15 Client:Soil & Environmental Engineers Sampled By:Client Sample Description Source:27.5' Depth Date Tested:09/22/15 Gray Silt with Brown PeatSample#:T15-0423 Tested By:CL Equipment Used GeoTac Sigma-1 Load Frame Load, psf 500 1000 2000 4000 8000 16000 32000 64000 16000 4000 1000 These values calculated from the incremental loading data. Comments: Reviewed by: Visit our website: www.mtc-inc.net One-Dimensional Consolidation performed in accordance with ASTM D2435/D2435M Corporate ~ 777 Chrysler Drive • Burlington, WA 98233 • Phone (360) 755-1990 • Fax (360) 755-1980 All results apply only to actual locations and materials tested. As a mutual protection to clients, the public and ourselves, all reports are submitted as the confidential property of clients, and authorization for publication of statements, conclusions or extracts from or regarding our reports is reserved pending our written approval. 1.087 Regional Offices: Olympia ~ 360.534.9777 Bellingham ~ 360.647.6111 Silverdale ~ 360.698.6787 Tukwila ~ 206.241.1974 1.372 1.016 0.751 0.784 0.891 Materials Testing & Consulting, Inc. Geotechnical Engineering • Special Inspection • Materials Testing • Environmental Consulting One-Dimensional Consolidation Report Void Ratio 2.553 2.469 2.334 2.069 1.666 Sample Preparation Natural Moisture Test Method Used Data Interpretation Procedure Procedure 2 (SqRt) Procedure 1 (Log) 0.65 1.15 1.65 2.15 2.65 100 1,000 10,000 100,000 Void Ratio Axial Effective Stress, (psf) Axial Strain versus Void Ratio Method A Inundated Method B DocuSign Envelope ID: AD7CAF2A-ED12-4A88-ACD2-89EFB0E3A881