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Home My WebLink About02928 - Technical Information Report - Geotechnical _ < DEVELOPMENT PLANNINCa� CITY C?, RcNT(�N SEP 2 � �''04 3 >...z;,�<' �'r�- ,r�F�(�,"n � ,_ �� ; ,, ., .. GEOTECHNICAL REPORT Amberwood 6001 NE 4th Street Renton, Washington Project No. T-4725-1 � � -. .. . ,,�:. :� �.�; � i _ _ ��a��= Terra Associates■ In . ��1/4��{`/2 ' b 4 4�� A .� 1 � } � �;t's� $ ° '`' � 3 � � �:.4�� .� `�, ..�..#'?.'.:�9k'3x:. �� .' :: �..� :: , :: � � V.��t .. ... .. . . . . ... ... . . . . �"- . ..._.....S�F:..::� �::a:i�} � :�i'�:::i :M:.i':::`. �i`eo`; . `�i i ' , Prepared for: � � Northwest Brokers . Bellevue, Washington N:�: � j:. September 15, 2000 :::�� T:t: �.:�; �� : � K :.. .Z 9Zg C6�Z�� OpaS� �� ry TERRA ASSOCIATES, Inc. Consultants in Geotechnical Engineering, Geology and Environmental Earth Sciences September 1�; 2000 Project No. T-472�-1 I Mr. Steven Beck Northwest Brokers 2708 East Main Avenue Puyallup,Washington 98372 Subject: Geotechnical Report Ambenvood 6001 NE 4th Street Renton, Washington Dear Mr. Beck: As requested, w�e have conducted a geotechnical engineering study for the subject site. The attached report presents our findings and recommendations for the geotechnical aspects of project design and construction. Our field exploration indicates the site is generally underlain by glacially-derived silty sand and sandy silt soils. In our opinion, these soil conditions �vill be suitable for development of the proposed residential subdivision, - � provided the recommendations presented in this report are incorporated into project design and construction. Up to appro�mately eight feet of uncontrolled fill is present in the southwestern corner of the site. Depending on I'I planned development in this part of the site, overexcavation and recompaction of the soils in this part of the site I may be required. We�;rill be available to assist you �vith devetopment of specific recommendations after the final 'I project plans have been completed. 'i . We trust this information is sufficient for your cunent needs. If you have any questions or require additional � information, please call. Sincerelti•yours, TERRA ASSOCIATES, INC. � �W'/C./��"' ,' � hr t' V . �, ^ ��-�,4 Patricia Reed ��''�.-�,�Q a;.:��-f'�, � Project Geologist�� .�,�'�-'�� r� � G�/I �� ,� - � Anil Butail P.E. ` �7'� � �. �� Principal ��s��' ��r.�`,�.�''�, PR/AB:d�p `�"��'�`� ��:� ��.�r'o� - _� ' 12525 V��illo�-vs Road, Suite 101, Kirkland, Washington 98034 Phone (425) 821-7777 � Fax f425) 821-4334 • terraCterra-associates.com � TABLE OF CONTENTS Page No. 1.0 Project Description..................................................................................................... 1 ' 2.0 Scope of Work............................................................................................................ 1 3.0 Site Conditions...........................................................................................................2 � 3.1 Surface...........................................................................................................2 3.2 Geolog}�.........................................................................................................2 3.3 Soils...............................................................................................................2 3.4 Groundwater..................................................................................................3 4.0 Geologic Hazards.......................................................................................................3 4.1 Erosion ..........................................................................................................3 � 4.2 Seismic.--�......................................................................................................3 �.0 Discussion and Recommendations ..............................................................................4 �.1 General..........................................................................................................4 5.2 Site Preparation and Grading..........................................................................5 �.3 Excavations....................................................................................................6 �.4 Foundations ...................................................................................................6 �.� Slab-on-Grade Construction...........................................................................7 �.6 Lo�ver-Level and Retaining Walls ..................................................................7 �.7 Drainage ........................................................................................................7 , �.8 Utilities..........................................................................................................8 t5.9 Pavements......................................................................................................8 6.0 Additional Services.....................................................................................................9 7.0 Limitations .................................................................................................................9 FiQures 'I ,� Vicinity Ma ........................................................... .................Fi ure 1 � p........................... ........... g ' Exploration Location Plan...............................................................................................Figure 2 Retaining Wall Drainage Detail .....................................................................................Figure 3 Typical Footing Drain Detail ........................................................................................Figure 4 Appendix Field E�cploration and Laboratory Testing................................................................. AppendiY A .' (I) � Geotechnical Report Amberwood 6001 N E 4th Street , Renton, Washington 1.0 PROJECT DESCRIPTION � The project consists of the development of a 4.59-acre parcel located at 6001 NE 4th Street in Renton, «'ashington. ��e understand that the project will consist of the construction of a 19-lot residential development. Specific design and site grading details were not available at the time of our study. Ho«�ever, we expect the - buildings �vill be single-family, one- to two-story residences �vith ��ood-frame construction imposing relatively light foundation loads. We e�pect structural loads �i ill be approYimately 20 to 40 kips per foot for isolated ' columns, and 1 to 2 kips per foot for continuous bearing �valls. Main floors will be constructed at grade or framed over a cra�vl space. Given the gentle slopes on the site, ��e expect the grading required to establish desired building elevations «�ill be moderate. '�' The recommendations in the following sections of this report are based on our understanding of the design features. If actual features vary or changes are made, �ve should review them in order to modify our recommendations, as required. �Ve should revie�v final design dra��ings and specifications to verify that our recommendations have been properly interpreted and incorporated into project design and construction. 2.0 SCOPE OF WORK On August 21, 2000, �ve excavated seven test pits to depths between three and ten feet belo�v existing surface grades. Using the information obtained from our subsurface exploration, «�e performed analyses to develop r geotechnical recommendations for project design and construction. Specificall}�, this report addresses the follo�ti�ng: _, • Soil and ground�vater conditions • Suitabilitv of native soils for use as fill � • Site preparation and grading • Foundation support � • Earth pressure parameters for basement or retaining��all design • Slab-on-grade support • Drainage • Excavations • Utilities • Pavements � September 15, 2000 Project No. T-4725-1 3.0 SITE CONDITIONS 3.1 Surface The subject site is located at 6001 NE 4th Street in Renton, �Vashington. The approximate location of the site is sho�vn on Figure 1. The site is bounded by SE 128th Street to the north, residential structures to the east, and land under development to the �vest and south. There is an existing residential subdivision north of the site, across SE � 128th Street. The eastern limits of the City of Renton cross the eastern portion of the site. The site is currently residential development, �vith an 1,8�0 square foot house, garage, and a tall barn/garage built in 1967. There are numerous older cars parked in the southern portion of the site. The northern portion of the site is covered bv a coniferous/broadleaf�voodland. No«�etland conditions have been identified on the site. __ We reviewed the U.S. Geological Survey (USGS) Ouadrangle Map for Renton, Washington, dated 1949, with photorevisions dated 1968 and 1973. According to the map, topographic elevations across the site range frorn approximately Elev. 520 inn the northeast comer to approximately Elev. 480 in the southwest corner. The current site layout is sho�vn on Figure 2. 3.2 Geoloev � ��/e revie�ved the Geologic Map of the Renton Ouadrangle, King Cot�nty, Washington, by D.R. 1�1u11ineauY, dated 1965. This map shows the soils at the site as quaternar}� ground moraine deposits (QGT). This unit is described as mostly thin ablation till over lodgment till deposited by the Puget glacial lobe. The lodgment till is generally a compact, coherent, unsorted mixture of sand, silt, clay, and gravel commonly kno�vn hardpan. Ablation till is similar, but much less compact and coherent. In general, lodgment till is � to 30 feet thick, and ablation till is 2 to 10 feet thick. 3.3 Soils , Topsoil � EYcavation of the test pits at the site revealed an approximately� three-inch thick layer of topsoil overl}�ing glacially derived units. Very Weathered Till Topsoil overlies ri��o to three feet of silt}� sand and sandy silt soils. The unit is a ver�� eathered till, generally 1 consisting of yellowish-brown to reddish-brow�n silty sand with gravel, cobbles, and some roots. This material is loose to medium dense and moist to drv. Cemented Till A less ��•eathered till material ��as encountered h�o to three feet belo�v the surface zone. This till consists of mottled gray and bro4�•n to gray silty sand ��rith gravel and cobbles. This material is medium dense to very dense and moist to dry. There appears to be a calcite cementation binding the till. Pa;e No. 2 September 15, 2000 Project No. T-472�-1 Fill The depth to till soils in Test Pits TP-1 and TP-2 indicates that the south�vestern comer of the site has been filled. - This is consistent �vith the sunounding topography and current site cor,ditions observed during our field explorations. The fill appears to be derived from cuts in the southeastern portion of the site, and used to create a more level surface. The fi(1 is assumed to deepen west of Test Pit TP-l. The fill consists of light }�ello«- to olive gra}� silty gravelly sand. The fill reached depths of eight feet in Test Pit TP-1 and six feet in Test Pit TP-2. The former surface is identified as dark bro�vn siltv sand «-ith a �vood debris � layer underlying the fill. The former soil horizon��as moist to damp and overlies the cemented till. Test Pit TP-2 �vas left open for approximately one hour to observe seepage. However, no groundwater seepage �vas observed. Detailed descriptions of the subsurface conditions encountered are presented in Appendix A. The approximate test pit locations are shown on Figure 2. 3.4 Groundwater We did not encounter groundwater seepage at the time of our recent explorations. Ho�vever, in I`'ovember 1998 and January• 1999, ��e drilled 17 test pits on the adjacent properties to the south and �tiest. At that time, groundw•ater�vas encountered to depths ranging from six inches to eight feet below eristing surface grades. In general, groundwater will develop in a perched condition above the glacial till. Fluctuations in ground«-ater I seepage Ievels are expected on a seasonal and annual basis. Ty�pically, groundwater seepage reaches maYimum I, � levels during and shortly follo�ving the wet �r7nter months. For these reasons, it is likely that perched � groundwater is present on the site dunng the�vinter months. 4.0 GEOLOGIC HAZARDS 4.1 Erosion � The soils encountered on-site are classified as Alden�ood gravelly sandy loam (zero to six percent slopes) b5�the I Soil Conservation Service (SCS). These soils are nearly level and undulating. Therefore, in our opinion, the I erosion hazard at the site is lo�v. '' 4.2 Seismic �i � The Puget Sound area falls «rithin Seismic Zone 3, as classified by the 1997 Uniform Building Code (UBC). ! Based on the soil conditions encountered and the local geology, from Table 16-J of the 1997 UBC, a soil profile i ty�pe of S� should be used for design purposes. ', Page No. 3 September 15, 2000 - Project No. T-472�-1 Liquefaction is a phenomenon �vhere there is a reduction or complete loss of soil strength due to an increase in �vater pressure induced by vibrations. Liquefaction mainly afFects geologicall_y recent deposits of fine-grained sands located below the ground�t�ater table. Soils of this nature derive their strength from intergranular friction. The generated «�ater pressure or pore pressure essentially separates the soil grains and eliminates this � intergranular friction, thus eliminating the soil's strength. Based on the soil and ground�vater conditions �ve encountered, it is our opinion the risk of site damage due to seismically-induced subsidence or liquefaction is minimal. 5.0 DISCUSSION AND RECOI��IMENDATIONS 5.1 General In our opinion, development of the site as proposed is feasible from a geotechnical standpoint. Z'he residential I� , structures can be supported on conventional spread footings bearing on competent native soils below the upper 24 to 30 inches of surficial fill and topsoil. Alternatively, if required by desired final building elevations, structural fill placed and compacted above these native soils can be used to support building foundations. Floor slabs and � pavements can be similarly supported. The native soils encountered at the site contain a significant amount of fines and �vill be difficult to compact as structural fill �;-hen too wet. The ability to use native soil from site excavations as structural fill �vill depend on its moisture content and the prevailing weather conditions at the time of construction. If grading activities will take place during the winter season, the o�;mer should be prepared to import free-draining granular material for use as structural fill and backfill. � We revie�ved a preliminary sketch of the site layout provided by l��ir. Steven Beck of Northn-est Brokers. The sketch indicates the construction of a stormwater retention pond in the southwestern comer of the site. The lo�ver till appears to slope toward the south�vest. The adjoining development has created a rockery supported cut of ', approximately eight feet along the south and west sides of the site. Placement of a storm�vater retention pond in this area will require overeYcavation if the depth of the pond is less than the esisting fill. It could also necessitate the placement of bentonite slurry as an impervious banier to seepage. Mr. Beck �vas on-site during the excavations and discussed construction the pond in the eastem corner of the site. This area �vould be less impacted by the eristing fill. However, the uncontrolled fill �rill remain an issue to be addressed for any development proposed in the south�vest corner of the site. The pond shou(d be lined �i�ith an impervious material, such as compacted glacial till. A residential structure may be placed in the south�vestern corner of the site if the pond is constructed in the southeastern corner. How•ever, this would require overexcavation and recompaction, or the use of deepened foundations to support the structure. � We can provide detailed recommendations regarding these issues and other geotechnical design considerations for the storm«�ater retention pond when the final plans are provided to us. Page No. 4 September 15, 2000 Project No. T-4725-1 5.2 Site Preparation and GradinQ To prepare the site for construction, demolition should include the complete removal of existing buildings from the site. This includes existing utilities, slabs, and foundations. According to available records at the King County Assessor's O�ce, the house has a septic system and gas heat. Any underground storage tanks (USTs) discovered during excavation must be removed b�� a licensed contractor and disposed of in accordance «-ith � Washington State regulations. r Follo�ving demolition, all vegetation, organic surface soils, and other deleterious matcrials should be strippcd an�i removed from the site. In general, surface stripping depths of appro�cimately 6 to 12 inches should be expected t remove organic topsoil. Stripped vegetation debris should be removed from the site. Organic topsoil will not b_ ' suitable for use as structural fill. Ho�vever, organic topsoil may be used for limited depths in non-structural areas or for landscaping purposes. Once clearing and stripping are complete, cut and fill operations can be made to establish desired pavement building grades. Prior to placing fill and preparing building and pavement subgrades, all exposed surfaces should be proofrolled to determine if any isolated soft and yielding areas are present. Proofrolling should also be performed in cut areas that will provide direct support for ne�v construction. If excessively yielding areas are observed that cannot be stabilized by compaction, they should be cut to firm ` bearing and filled to grade �vith structural fill. If the depth of ercavation to remove unstable soils is excessive, using a geotextile fabric, such as Mirafi �OOX or equivalent, in conjunction �vith structural fill should be considered. A minimum of 18 inches of clean granular structural fill over the geotextile fabric should establish a stable bearing surface. , A representative from our office should observe all proofrolling operations. �Ve also recommend field evaluations at the time of construction to verif}�stable subgrades. The ability to use native soils from site excavations as structural fill will depend on their moisture content and the prevailing weather conditions when site grading activities take place. If grading activities are planned during thc �vet winter months, or if they are initiated during the summer and extend into fall and «�inter, the owner should be prepared to import wet weather structural fill. For this purpose, «�e recommend using a granular soil that meets the follo«ing grading requirements: U.S. Sieve Size Percent Passing 3 inches 100 No. 4 75 ma.�cimum No. 200 5 maximum* *Based on the 3/�3-inch fraction Prior to use,Terra Associates, Inc. should e�amine and test all materials proposed for use as structural fill. Page No. � September 1�, 2000 Project No. T-4725-1 Structural fill should be placed in uniform loose layers not exceeding 12 inches and compacted to a minimum of 9� percent of the soil's masimum dry density, as determined by ASTM Test Designation D-698 (Standard Proctor). The moisture content of the soil at the time of compaction should be within t�ti�o percent of its optimum, as determined by this ASTM standard. In non-structural areas or for backfill in utility trenches belo�v a depth of 4 feet,the degree of compaction can be reduced to 90 percent. } 5.3 Excavations All excavations at the site associated with confined spaces, such as utility trenches and lower building levels, must be completed in accordance «�th local, state, or federal requirements. Based on current Occupational Safety and Health Administration (OSHA) regulations, soils on the site�vould be classified as T}pe B soils. Accordingly, for excavations exceeding 4 feet but less than 20 feet deep, the side slopes should be laid back at a minimum slope inclination of l:l (Horizontal:Vertical). Alternatively, a shoring trench boY can be used to � support utility trench side�valls. This information is provided solely for the benefit of the owner and other design consultants, and should not be construed to imply that Terra Associates, Inc. assumes responsibility for job site safety. Job site safety is the sole � responsibility of the project contractor. � 5.4 Foundations Spread Footings Residential structures may be supported on conventional spread footing foundations bearing on competent native soils or on structural f lls placed above competent native soils. Foundation subgrades should be prepared as recommended in Section 5.2. Perimeter foundations should be at a minimum depth of 1.5 feet belo�;� final exterior grades. Interior foundations can be constructed at any convenient depth belo�v the floor slab. «e recommend designing foundations for a net allo�vable bearing capacity of 2,000 pounds per square foot (ps�. For short-term loads, such as r��ind and seismic, a one-third increase in this allowable bearing capacity can be used. With this bearing pressure and anticipated structural loads, «�e estimate total and differential settlements of appro�imately one inch and one-half inch, respectively. For designing foundations to resist lateral loads, a base friction coefficient of 0.3 can be used. Passive earth pressures acting on the sides of the footings and buried portions of the foundation stem �valls can also be considered. We recommend calculating this lateral resistance using an equivalent fluid �veight of 300 pounds per cubic foot (pcfl. We recommend not including the upper 12 inches of soil in this computation because it can be affected by ��eather or disturbed by future grading activity. This value assumes the foundations �vill be constructed neat against competent native soil or backfilled �L�ith structural fill; as described in Section 5.2. The values recommended include a saferi�factor of 1.�. Page No. 6 September 15, 2000 Project ti'o. T-�372�-1 5.5 Slab-on-Grade Construction Slabs-on-grade may be supported on the subgrade prepared as recommended in Section �.2. Immediatel}� belo« the floor slabs, �ve recommend placing a four-inch thick capillary break layer of clean, free-draining sand �r gravel having less than three percent passing the I�To. 200 sieve. This material will reduce the potential for up«-ar capillary movement of water through the underlying soil and subsequent wetting of the floor slab. Where moisture by vapor transmission is undesirable, a durable plastic membrane should be placed on the capillary break layer. The membrane should be covered ��ith ttvo inches of clean, moist sand to guard against damage during construction and to aid in curing of the concrete. 5.6 Low�er-Level and Retaining Walls The magnitude of earth pressure development on lower-level or retaining walls �vill depend, in part, on the quality of wall backfill. �Ve recommend placing and compacting �vall backf`ill as structural fill. Belo«r improved areas, such as pavements or floor slabs, the bac�ll should be compacted to a minimum of 9� percent of its maYimum } dr}� unit �veight, as determined by AST1�1 Test Designation D-698 (Standard Proctor). In unimproved areas, the ' relative compaction can be reduced to 90 percent. To guard against hydrostatic pressure development, �vall drainage must also be installed. A tr�pical recommended �vall drainage detail is sho��m on Figure 3. «ith �vall backfill placed and compacted as recommended and drainage properl5� installed, �i�e recommend -- designing unrestrained �valls for an active earth pressure equivalent to a fluid weighing 35 pcf. For restrained walls, an additional uniform lateral pressures of 100 psf should be added. These values assume a horizontal backfill condition and that no other surcharge loading, such as traffic, sloping embankments, or adjacent buildings will act on the�vall. If such conditions exist, the imposed loading must be included in the �r�all design. Friction at the base of foundations and passive earth pressure will provide resistance to these lateral loads. Values for these parameters are provided in Section 5.4. 5.7 Drainaae Surface Fina.l exterior grades should promote free and positive drainage a�vay from the site at all times. ��'ater must not be allowed to pond or collect adjacent to foundations or ��thin the immediate building areas. We recommend providing a gradient of at least three percent for a minimum distance of ten feet from the residential structures, eYcept in paved locations. In paved locations, a minimum gradient of one percent should be pro�zded unless provisions are included for col(ection and disposal of surface«�ater adjacent to the structures. Page No. 7 September 15, 2000 Project No. T-4725-1 Subsurface We recommend installing perimeter foundation drains adjacent to all structures ��7th main floors framed over a cra�vl space or constructed at grade �vith an elevation equal to or below the final e�cterior grade. If the floors are constructed at grade and elevated above the adjacent outside grade, the o�r-ner may elect to eliminate the foundation drains. However, positive drainage away from the structures must be established. A typical recommended drain detail is shown on Figure 4. Subsurface drains must be laid «�ith a gradient sufficient to promote positive flo�ti� to a controlled point of approved discharge. 5.8 Utilities Utility pipes should be bedded and backfilled in accordance��ith American Public�Vorks Association (APWA) or King County specifications. As a minimum, trench backfill should be placed and compacted as structural fill, as described in Section 5.2. As noted, soils excavated on-site should be suitable for use as backfill material in dry �veather, provided the moisture content can be controlled to facilitate proper compaction. If utility construction tal:es place during the winter, it«�I1 be necessary to import suitable «�et��•eather fill for utilit��trench backfilling. 5.9 Pavements Pavements should be constructed on subgrades prepared as described in Section 5.2. Regardless of the relative compaction achieved, the subgrade must be firm and relatively unyielding before paving. Proofrolling the subgrade with heavy construction equipment should be completed to verify this condition. The pavement section is dependent on the supporting capability of the subgrade soils and the trafFic conditions to �vhich it �vill be subjected. We understand that traffic �vill mainly consist of light passenger and commercial vehicles w•ith only occasional hea�y traffic in the form of moving trucks and trash removal vehicles. Based on this information, with a stable subgrade prepared as recommended, we recommend the follo�ving pavement sections: • T«�o inches of asphalt concrete(AC) over six inches of crushed rock base (CRB) • T�vo inches of AC over four inches of asphalt-treated base (ATB) The paving materials used should conform to the Washington State Department of Transportation («'SDOT) specifications for Class B asphalt concrete, ATB,and CRB surfacing. Long-term pavement performance �vill depend on surface drainage. A poorly-drained pavement section will be subject to premature failure as a result of surface ��ater infiltrating into the subgrade soils and reducing their supporting capability. To improve performance, «�e recommend surface drainage gradients of at least rit�o percent. Some longitudinal and transverse cracking of the pavement surface should be e�pected over time. Regular maintenance should be planned to seal cracks �r�hen they occur. Page No. 8 r September 15, 2000 Project No. T-472�-1 6.0 ADDITIONAL SERVICES Terra Associates, Inc. should revie«� the final design and specifications in order to �-erif}� that eanh«ork and . foundation recommendations have been properly interpreted and incorporatecl into project design. We should also provide geotechnical services during construction in order to observe compliance «ith the design concepts; specifications, and recommendations. This will allo�v for design changes if subsurface conditions differ from those anticipated prior to the start of construction. 7.0 LI��ZITATIONS We prepared this report in accordance ��ith generally accepted geotechnical engineering practices. This report is the property of Terra Associates, Inc. and is intended for specific application to the Ambenvood site. This report is for the exclusive use of North�vest Brokers and their authorized representatives. I�'o other warranri, eYpressed or imptied, is made. 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N r---- � Ep� --i � '� Q�J ,�` �' =�`� .v4i SE 1.7er�i 'SE P38TH �a <� = SE 138TH PL = LIBER SE 138TH ST I � ,fpf�`„4�a •'�JF �SE IJ9iN Pl� ��S�Ct'� � � F- �-- HS r� ��p � fl lJ9rN a r-��6 `�v`�., SE 139TH N =; �0 139TH PL `o o � SE H I _J s[ l�arx s� t� PL .n -- � �1 NI `iioni vi � N „f u�n ~ �� SE 141ST ^ �M4PC -r�—0 14 li � ...I � d �i� ST �� ' I �� u um I ST o �HFIGIfT "� o � ^SE 742ND ST I vi I :� �" ' j� 142N0 ST - �� SE 142ND .'�', „?PARK;,�; a SEa S�`' �i ,.,�o� SE�laz�o� - R-' SE I42ND Si lA�' $T � 14: /�`rF�'c�4.p" ..fj � PL a �-�I (�, i St u7 � '' = N o �� ¢r ,I - �\: "' SE 1�]uD�Z = �i � �l o u u r o n 5� S Q�' S E 1 4 3 S T �� I ii�+ol,`�� e qti+\�44TM"' �� ST Pi ; - '��o+ k+o' � S E � 1 4 4 T H v+ $�oi . `ti�\:a� a aSE 14��`r : � ` . � e $T ------�-^ �'�3'�'�4. SrN�-L-4 N � sE taiH 15900= .,� �, . � 'J�� '��i�`-� � J �'O - J:t�_��F N $T R ..� % �` ` _� F', iKTMs ct`SM � ;( N < ` 'W^o x 1. _ � �`' `�- �N > � �',� _� _�' W ='I'Stw � SE ' ZSf �. _ � vi �n i�sra.`-. �� ; } o � � b °• MID ■ 0 :..'�.. �:� .a �" � i _". J�f Q��GO $f I 87H �'o , � ySE�Il7TN $T� a ,� � , �._C . E M �":• � �' � \� � S7 � 7� SE � � � � I Sp b �. S ;R� Ea''P ,�:::22 ":" k = �arv��a� `� �`'b e�' ��_ �� S T�°A' �.,� � a 49 NTpN RI R r a,aREG10NA�.�i , �: -^� Jn.. I^ _" REFERENCE: THE THOMAS GUIDE, METROPOLITAN PUGET SOUND, PAGES 626, 627, 656 AND 657, 2000 EDITION. VICINITY MAP - �•- �� TERRA AMBERWOOD ••• ASSOC I ATE S RENTON, WASHINGTON Geotechnical Consultants Proj.No. 4725-1 Date SEPT. 2000 Figure 1 �'�'E. 4th, Street (SE. 128th Street) - -�---r----r-- �-- -- -�--r- , , ; � � I 4 I ; � , � , I � I 2 I 3 ----------- I � � � I I � - � , � � � , , TP 6 � . ,iy� � ( 5 ; I I � I TP-' ' � I � , , � , �____�_____�____ ________ -- , � � �_____ _____ ___ _______� I APPROXIMATE SCALE i T � � � 80 0 80 16Q feet � ; , ; 1 � I I I � 9 I � � E . i 6 � � � 8 ��---=--------{ i LEGEND: � � ( � � .__ _�.,_ 10 i ( � APPROXIMATE TEST PIT LOCATION � �--—-- - � �----- _ __—_____—__ � REFERENCE: , �� W � ( >_ ( FACSIMILES OF UNDATED AND UNTITLED SITE PLANS � 14 ( Ex� � � � � PROVIDED BY CLIENT. � � BLD.,. � � � � � __-"-"-r_� �� . . � � �---------� I NOTE: ' t THIS SITE PLAN WAS CREATED USI�JG LOCATIONS AND � 15 � � � � 2 i DIMENSIONS FOUND ON THE REFERENCED SITE PLANS. � TP-5� � DUE TO DISTORTION COMMON WITH FACSIMILES, ALL ------ -�- , - - , �_____�_________�- LOCATIONS AND DIMENSIONS SHOU�D BE CONSfDERED ' Ex. i TO BE APPROXIMATE. � 16 � � BLDG � i --- ---- -----� i ': � '. t f I � i ��`i- APPROXIMATE AREA � �� OF EXISTING FILL ' `# 17 � � 18 I 19 I I � �� _ ' � i�� j TP-4 I , -- , � ; � - TP-2 � �TP-3 � ' -----�-----�-- � ( TP I . -- : 1 ; � � PROPOSED STGRM �OND � 20 � , �__ __ ' _� __L__ __� EXPLORATION LOCATION PLAN �� TERRA AMBERWOOD .•. ASSOCIATES RENTON, WASHINGTON Geotechnical Consultants Proj.No. 4725-1 Date SEPT. 2000 Figure 2 12" MINIMUM WIDE FREE—DRAINING GRAVEL SLOPE TO DRAIN � -- I 12'� ;,.`,. I,� ; � \,'� �o o / , o / � � � .� /� , '^ � COMPACTED � 'c o , STRUCTURAL FILL �%� •.c o / . � �c o i c ^ � . 'o o a ;' EXCAVATED SLOPE , . � � � , (SEE REPORT TEXT FOR APPROPRIATE ' ° ° a � INCLINATIONS) 000 �� / � o c o �� o�o c c o ' 12" OVER PIPE - 0 0 0 Q�O,�C�O�O O C C / . �a��4 � .� /�i .<i.� .� /.� .� L� i�• • . . ' . C � . � . • ' o � :� . . . . i . , i, . .� � 3" BELOW PIPE 4" DIAMEfER PERFORATED PVC PIPE NOT TO SCALE RETAINING WALL DRAINAGE DETAIL �� TERRA AMBERWOOD .•. ASSOCIATES RENTON, WASHINGTON Geotechnical Consultants Proj.No. 4725-1 Date SEPT. 2000 Figure 3 BUILDING SLAB _ \�%\�/�\'%\'i /. �//. � /��/. � /. �� / � . : _ � . � ` _COMPACTED . �\�\ S�RUCTURAL . �. \ . : - � . � -BACK.FILL , / � - � \ . / , \ . � � . i%/i!/�;! . o o �o°g �, \ � o o � i . � . . . � . � . � . � . � . � . � . \, ,� �, j� ; , �,��\ /� i � //� /� /� � %i� i� � / ;/ 4" PERFORATED PVC PIPE 3/4" WASHED ROCK NOT TO SCALE I� TYPICAL FOOTING DRAIN DETAIL - � TERRA AMBERWOOD .•. ASSOCIATES RENTON, WASHINGTON Geotechnical Consultants Proj.No. 4725-1 Date SEPT. 2000 Figure 4 APPENDIX A FIELD EXPLORATIO\`AND LABORATORY TESTING Amberwood Renton, `Vashington On August 21, 2000, «�e performed our field etploration using a rubber-tired backhoe. We explored subsurface soil conditions at the site by excavating seven test pits to depths of between three and ten feet below eYisting surface grades. The test pit locations are sho�vr► on Figure 2. The test pit logs are presented on Figures A-2 through A-5. A geologist from our office conducted the field exploration, classified the soil conditions encountered, maintained a log of each test pit, obtained representative soil samples, and observed pertinent site features. All soil samples �4•ere visually classified in accordance �vith the Unified Soil Classification System (USCS) described on Figure A- 1. Representative soil samples obtained from the test pits �cere placed in closed containers and taken to our laboratory for further examination and testing. The moisture content of each sample �vas measured and is reported on the test pit logs. Grain size anal��ses �t�ere performed on three of the samples. The results are sho«n on Figures A-6 and A-7. � MAJOR DIVISIONS LETTER TYPICAL DESCRIPTION SYMBOL I � Clean ; GW Well-graded gravels, gravel-sand mixtures, little or no GRAVELS G�avels ! fines. J � (lesS than ' G P I Poorly-graded gravels, gravel-sand mixtures, little or O � N ' More than 5% fines) ; no fines. � �'� 50% of Coafse Siity gravels, gravel-sand-silt mixtures, non-plastic .` � ; fraction is � GM fnes. � � � i larger than No. Gravels _ ��— 4 sieve I with fines Z <n i (�jC Clayey gravels, gravel-sand-clay mixtures, plastic fines ' Q oo � - � o� Clean ' � I S�/ Well-graded sands, gravelly sands, little or no fines. � o SANDS Sands ___ � �Z (less th8n Poorly-graded sands or gravelly sands, little or no .� c More than 5/o fines) SP fines. � � `J � 50% of coarse � �� ffaCtiOn is SM Silty sands, sand-silt mixtures, non-plastic fines. U g smaller than Sands No. 4 sieve with fines SC Clayey sands, sand-clay mixtures, plastic fines. i � Inorganic silts, rock flour, clayey silts with slight J .�°o SILTS AND CLAYS M� plasticiry. O �� CL Inorganic clays of low to medium plasticity, (lean clay) � E o Liquid limit is less than 50°/a ' — � o Z•� � OL Organic silts and organic clays of low plasticity. Z � c�a � ' Q � "-' � � M H Inorganic silts, elastic. � s a�� SILTS AND CLAYS W � � ' CH j Inorganic clays of high plasticity, fat clays. z o �n ' Liquid limit is greater than 50% LL. � QH Organic clays of high plasticity. HIGHLY ORGANIC SOILS PT Peat. DEFINITION OF TERMS AND SYMBOLS w Standard Penetration � 2�� OUTSIDE DIAMETER SPLIT Q Density Resistance in Blows/Foot ., SPOON SAMPLER � � Very loose 0-4 � 2.4" INSIDE DIAMETER RING SAMPLER o Loose 4-10 _L OR SHELBY TUBE SAMPLER Medium dense 10-30 z Dense 30-50 Z WATER LEVEL (DATE) � Very dense >50 . Tr TORVANE READINGS, tsf Standard Penetration Pp PENETROMETER READING, tsf g ' Consistency Resistance in Blows/Foot DD DRY DENSITY, pounds per cubic foot v Very soft 0-2 LL LIClUID LIMIT, percent o Soft 2-4 � Medium stiff 4-8 PI PLASTIC INDEX J Stiff 8-16 � Very stiff 16-32 N STANDARD PENETRATION, blows per foot Hard >32 UNIFIED SOIL CLASSIFICATION SYSTEM TERRA AMBERWOOD ASS�CIATES KING COUNTY, WASHINGTON Geotechnical Consultants Proj. No. T-4725-1 Date SEPT 2000 Figure A-1 Test Pit No. TP-1 Logged by: PR Date: 8/21/00 Depth Moisture {ft.) Soil Description �(%}nt � 3inchestopsoil. FILL:lightyeilowish-brownsiltygravellysand,mediumdense,dry. (SM) 5 �2 DarkbrownsiftySANDwithwooddebris,organicodor,mediumdense,moist. (SM) Olive-graysiltygravellySAND,moderatelycemented,verydense,moist. (SM) 14 10 Test pitterminated at 10 feet. No groundwater encountered. 15 Test Pit No. TP-2 Logged by: PR Date: 8/21/00 Depth Moisture (ft.) Soil Description ��o�nt , 0 , FILL:lightolive-graysiltygravellysand,mediumdense,moisttodry. (SM) FILLreddish-brownsiltygravellysand,withwoodydebris,medium 20 , dense,dry. (SM) , 5 Olive-gray silty gravelly SAND,moderately cemented,very dense, moist. (SM) �q j �� Testpitterminatedat9feet. No groundwater encountered. i 15 � TEST PIT LOGS � TERRA AMBERWOOD '� � ' ASSOCIATES KING COUNTY, WASHINGTON Geotechnical Consultants ' Proj. No. T-4525-1 I Date SEPT 2000� Figure A-2 '� Test Pit No. TP-3 Logged by: PR Date: 8/21!00 Depth Moisture �ft'� Soil Description � {joj nt 0 Reddish-brown siltygravelly SAND,with organic debris(wood and roots), mediumdense,dry. (SM) Olive-graysilty gravelly SAND,moderately cemented,very dense,moist. (SM) � 12 Testpitterminated at6feet. No groundwater encountered. 10 Test Pit No. TP-4 Logged by: P R Date: 8/21/00 I Depth Moisture I Content �ft�� Soil Description �a�o� 0 Yellowish-brown silty gravelly SAND, medium dense, dry. (SM) Olive-gray silty gravelly SAND, moderately cemented, very dense, moist. (SM) � 7 Test pit terminated at 5 feet. No groundwater encountered. 10 TEST PIT LOGS TERRA AMBERWOOD � � ASSOCIATES KING COUNTY, WASHINGTON Geotechnical Consultants � Proj. No. T-4525-1 j Date SEPT 2000, Figure A-3 Test Pit No. TP-5 Logged by: PR Date: 8/21/00 Depth Moisture �ft�� Soil Description C��tj nt 0 Yellowish-brown silty gravelly SAND, medium dense, dry. (SM) Olive-gray silty gravelly SAND, moderately cemented, very dense, dry. (SM) �� 5 Test pit terminated at 5 feet. No groundwater encountered. 10 Test Pit No. TP-6 Logged by: PR Date: 8/21100 Depth Moisture Content �ft�� Soil Description {o�o� I, � Reddish-brown silty SAND with gravel,with organic debris(wood and roots), loose, dry. (SM) ' Olive-gray silty gravelly SAND, moderately cemented, very dense, moist. 8 Test pit terminated at 3 feet. , 5 No groundwater encountered. I 10 TEST PIT LOGS TERRA AMBERWOOD � � ASSOCIATES KING COUNTY, WASHINGTON Geotechnical Consultants ; Proj. No. T-4525-1 Date SEPT 2000� Figure A-4 I, Test Pit No. TP-7 Logged by: PR Date: 8/21/00 Depth Moisture �ft�� Soil Description C��oj nt 0 Reddish-brown silty gravelly SAND, loose, dry. (SM) Olive-gray silry gravelly SAND, moderately cemented, very dense, dry. (SM) 10 5 Testpitterminatedat4feet. No groundwater encountered. 10 TEST PIT LOGS TERRA AMBERWOOD �� •=' ' � ASSOCIATES KING COUNTY, WASHINGTON Geotechnical Consultants Proj. No. T-4525-1 �i Date SEPT 2000� Figure A-5 � � ,�, � � � � �� i � � �'�� • • • • � • • • • • � �� -��_��-_��-��-�� , -��__��---__-��-��_- � ��►��■■■■�� ■�■■■��w��■■ � •� ��■�■��■��■�■�� ■■■�� / ��■��■■■�� : ��■��a■■�►��■�■■�� ■■■�� ► •� ��►��■■■�� ' CC��C�:�`.��.�C�C��::C��C:C::�C� � . 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