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FOR REFERENCE BLD2022-1323+Geotechnical_Report+9.30.2022_7.32.37_PM+3140204RECEIVED 10/7/22 BLD2022-1323 CITY OF EDMONDS elm DEVELOPMENT SERVICES DEPARTMENT I LW REVIEWED RILEYGROUP BY CITY OF EDMONDS GEOTECHNICAL ENGINEERING REPORT PREPARED BY: THE RILEY GROUP, INC. 17522 BOTHELL WAY NORTHEAST BOTHELL, WASHINGTON 98011 PREPARED FOR: HOUSING HOPE 3331 BROADWAY EVERETT, WASHINGTON 98201 RGI PROJECT No. 2021-319-1 HOUSING HOPE EDMONDS 82XX 236TH STREET SOUTHWEST EDMONDS, WASHINGTON 98026 JUNE 17, 2021 Corporate Office 17522 Bothell Way Northeast Bothell, Washington 98011 Phone 425.415.0551 + Fax 425.415.0311 www.riley-group.com mom 1 Lu RILEYGROUP June 17, 2021 Todd Bullock Housing Hope 3331 Broadway Everett, Washington 98201 Subject: Geotechnical Engineering Report Housing Hope Edmonds 82XX 236th Street Southwest Edmonds, Washington RGI Project No. 2021-319-1 Dear Mr. Bullock: As requested, The Riley Group, Inc. (RGI) has prepared this Geotechnical Engineering Report (GER) for the above -referenced site. Our services were completed in accordance with our proposal 2021-319-PRP1 dated May, 2021 and authorized by the client on May 18, 2021. The information in this GER is based on our understanding of the proposed construction, and the soil and groundwater conditions encountered in the test pits completed by RGI at the site on June 2, 2021. RGI recommends the project plans and specifications be submitted for a general review so that RGI may confirm that the recommendations in this GER are interpreted and implemented properly in the construction documents. RGI also recommends that a representative of our firm be present on site during portions of the project construction to confirm that the soil and groundwater conditions are consistent with those that form the basis for the engineering recommendations in this GER. If you have any questions or require additional information, please contact us. Respectfully submitted, THE RILEY GROUP, INC. �e o{ Wash/ O2698 ed Ge ERIC L. WOODS Eric L. Woods, LG Project Geologist RUNQI k,:"111 0� �13 SSj�NAL�� Ricky R. Wang, PhD, PE Principal Engineer Coiporate Office 17522 Bothell Way Northeast Bothell, Washington 98011 Phone 425.415.0551 4 Fax 425.415.0311 �/ 1 -7 1111. 1 wiv}v. riley-group. coin elm 1 LW RILEYGROUP TABLE OF CONTENTS 1.0 INTRODUCTION.................................................................................................................................... 1 2.0 PROJECT DESCRIPTION......................................................................................................................... 1 3.0 FIELD EXPLORATION AND LABORATORY TESTING.............................................................................. 1 3.1 FIELD EXPLORATION................................................................................................................................... 1 3.2 LABORATORY TESTING................................................................................................................................ 2 4.0 SITE CONDITIONS................................................................................................................................. 2 4.1 SURFACE..................................................................................................................................................2 4.2 GEOLOGY.................................................................................................................................................2 4.3 SOILS.......................................................................................................................................................2 4.4 GROUNDWATER........................................................................................................................................3 4.5 SEISMIC CONSIDERATIONS...........................................................................................................................3 4.6 GEOLOGIC HAZARD AREAS..........................................................................................................................4 5.0 DISCUSSION AND RECOMMENDATIONS............................................................................................. 4 5.1 GEOTECHNICAL CONSIDERATIONS .................................................................................................................4 5.2 EARTHWORK.............................................................................................................................................4 5.2.1 Erosion and Sediment Control.....................................................................................................4 5.2.2 Excavations...................................................................................................................................5 5.2.3 Stripping and Site Preparation.....................................................................................................6 5.2.4 Structural Fill................................................................................................................................7 5.2.5 Cut and Fill Slopes........................................................................................................................8 5.3 FOUNDATIONS..........................................................................................................................................8 5.4 RETAINING WALL.......................................................................................................................................9 5.5 SLAB -ON -GRADE CONSTRUCTION............................................................................................................... 10 5.6 DRAINAGE..............................................................................................................................................10 5.6.1 Surface.......................................................................................................................................10 5.6.2 Subsurface..................................................................................................................................11 5.6.3 Infiltration..................................................................................................................................11 5.7 UTILITIES................................................................................................................................................11 5.8 PAVEMENTS............................................................................................................................................11 6.0 ADDITIONAL SERVICES....................................................................................................................... 12 7.0 LIMITATIONS.......................................................................................................................................12 LIST OF APPENDICES Figure1.....................................................................................................................Site Vicinity Map Figure 2............................................................................................... Geotechnical Exploration Plan Figure 3...............................................................................................Retaining Wall Drainage Detail Figure 4....................................................................................................Typical Footing Drain Detail Appendix A..........................................................................Field Exploration and Laboratory Testing Corporate Office 17522 Bothell Way Northeast Bothell, Washington 98011 Phone 425.415.0551 + Fox 425.415.0311 www.riley-group.com Geotechnical Engineering Report June 17, 2021 Housing Hope Edmonds, Edmonds, Washington RGI Project No. 2021-319-1 Executive Summary This Executive Summary should be used in conjunction with the entire GER for design and/or construction purposes. It should be recognized that specific details were not included or fully developed in this section, and this GER must be read in its entirety for a comprehensive understanding of the items contained herein. Section 7.0 should be read for an understanding of limitations. RGI's geotechnical scope of work included the excavation of six test pits to depths up to 8.5 feet below ground surface (bgs). Based on the information obtained from our subsurface exploration, the site is suitable for development of the proposed project. The following geotechnical considerations were identified. Soil Conditions: The site is underlain by up to 3.5 feet of loose to medium dense fill comprised of silty sand with some gravel over native deposits of loose to medium dense silty sand with some gravel over dense silty sand with varying amounts of gravel glacial till. Groundwater: Groundwater was not encountered during our test exploration. Foundations: Foundations for the proposed building can be supported on conventional spread footings bearing on medium dense native soil or structural fill. Slab -on -grade: Slab -on -grade floors for the proposed building can be supported on medium dense native soil or structural fill. Pavements: The following pavement sections are recommended: ➢ For general parking areas: 3 inches of Hot Mix Asphalt over 6 inches of CRB over firm subgrade Geotechnical Engineering Report 1 June 17, 2021 Housing Hope Edmonds, Edmonds, Washington RGI Project No. 2021-319-1 1.0 Introduction This Geotechnical Engineering Report (GER) presents the results of the geotechnical engineering services provided for the proposed Housing Hope Edmonds in Edmonds, Washington. The purpose of this GER is to assess subsurface conditions and provide geotechnical recommendations for the construction of a new building to the south of the existing building with a detention pond. Our scope of services included field explorations, laboratory testing, engineering analyses, and preparation of this GER. The recommendations in the following sections of this GER are based upon our current understanding of the proposed site development as outlined below. If actual features vary or changes are made, RGI should review them in order to modify our recommendations as required. In addition, RGI requests to review the site grading plan, final design drawings and specifications when available to verify that our project understanding is correct and that our recommendations have been properly interpreted and incorporated into the project design and construction. 2.0 Project Description The project site is located to the 82XX 236th Street Southwest in Edmonds, Washington. The approximate location of the site is shown on Figure 1. The site includes a tax parcel of 1.35 acres in size. RGI understands that the project will include two multi -family residential buildings about 55,215 square feet with related parking. The building will be three-story above the ground surface without any basement. RGI's understanding of the project is based on a conceptual site plan prepared by Designs Northwest Architects dated March 19, 2021. At the time of preparing this report, detailed building plans were not available for us to review. RGI anticipates that the proposed building will be supported on perimeter walls with bearing loads of 3 to 6 kips per linear foot, and a series of columns with a maximum load up to 500 kips. Slab -on -grade floor loading of 250 pounds per square foot (psf) are expected. RGI also expects that some grading will be needed to reach the final grade. 3.0 Field Exploration and Laboratory Testing 3.1 FIELD EXPLORATION On June 2, 2021, RGI observed the excavation of six test pits in the building and parking area. The approximate exploration locations are shown on Figure 2. Field logs of each exploration were prepared by the geologist who continuously observed the drilling. These logs included visual classifications of the materials encountered during low 1 LU RILEYGPOUP Geotechnical Engineering Report 2 June 17, 2021 Housing Hope Edmonds, Edmonds, Washington RGI Project No. 2021-319-1 drilling as well as our interpretation of the subsurface conditions between samples. The test pit logs included in Appendix A represent an interpretation of the field logs and include modifications based on laboratory observation and analysis of the samples. 3.2 LABORATORY TESTING During the field investigation, a representative portion of each recovered sample was sealed in containers and transported to our laboratory for further visual and laboratory examination. Samples retrieved from the test pits were tested for moisture content and grain size analysis to aid in soil classification and provide input for the recommendations provided in this GER. The results and descriptions of the laboratory tests are enclosed in Appendix A. 4.0 Site Conditions 4.1 SURFACE The entire site is a rectangular -shaped property comprised of one tax parcel with a total area of about 1.35 acres. The site is bound to the north and east by residential properties, to the west by Edmonds Lutheran Church, and to the south by 236th Street Southwest. The site is currently an undeveloped, vacant lot. The site is relatively level with less than eight feet of elevation change across the property. The site is vegetated with grass and several small- to medium -diameter trees. 4.2 GEOLOGY Review of the Geologic Map of the Edmonds East and part of the Edmonds West Quadrangles, Washington by James P. Minard (1983) indicates that the soil in the project vicinity is mapped as Till (Map Unit Qvt) which is a compact mixture of clay, silt, sand, and gravel deposited by glacial ice. These descriptions are generally similar to the findings in our field explorations. 4.3 SOILS The site is underlain by up to 3.5 feet of loose to medium dense fill comprised of silty sand with some gravel over native deposits of loose to medium dense silty sand with some gravel over dense silty sand with varying amounts of gravel glacial till. More detailed descriptions of the subsurface conditions encountered are presented in the test pit logs included in Appendix A. Sieve analyses were performed on three selected soil samples. The grain -size distribution curves are included in Appendix A. o 1 LU RILEYG?(''J Geotechnical Engineering Report 3 Housing Hope Edmonds, Edmonds, Washington June 17, 2021 RGI Project No. 2021-319-1 4.4 GROUNDWATER Groundwater was not encountered during our field exploration to a maximum depth of 8.5 feet bgs. It should be recognized that fluctuations of the groundwater table will occur due to seasonal variations in the amount of rainfall, runoff, and other factors not evident at the time the explorations were performed. In addition, perched water can develop within seams and layers contained in fill soils or higher permeability soils overlying less permeable soils following periods of heavy or prolonged precipitation. 4.5 SEISMIC CONSIDERATIONS Based on the International Building Code (IBC), RGI recommends the follow seismic parameters for design. Site Soil Class' Site Latitude Site Longitude Table 1 IBC Parameter 2015 Value 2018 Value CZ 47.785575 Short Period Spectral Response Acceleration, Ss (g) 1-Second Period Spectral Response Acceleration, Sl (g) Adjusted Short Period Spectral Response Acceleration, SMs (g) Adjusted 1-Sec Period Spectral Response Acceleration, SM1 (g) Numeric seismic design value at 0.2 second; SDS(g) -122.344157 1.262 1.278 0.493 0.448 1.262 1.533 0.644 0.6723 0.842 1.022 Numeric seismic design value at 1.0 second; SD1(9) 0.43 0.448' 1. Note: In general accordance with Chapter 20 of ASCE 7-10. The Site Class is based on the average characteristics of the upper 100 feet of the subsurface profile. 2. Note: The 2015 IBC and ASCE 7-16 require a site soil profile determination extending to a depth of 100 feet for seismic site classification. The current scope of our services does not include the required 100 foot soil profile determination. Test pit explorations extended to a maximum depth of 8.5 feet, and this seismic site class definition considers that similar soil continues below the maximum depth of the subsurface exploration. Additional exploration to deeper depths would be required to confirm the conditions below the current depth of exploration. 3. Note: In accordance with ASCE 11.4.8, a ground motion hazard analysis is not required for the following cases: • Structures on Site Class E sites with Ss greater than or equal to 1.0, provided the site coefficient Fa is taken as equal to that of Site Class C. • Structures on Site Class D sites with S, greater than or equal to 0.2, provided that the value of the seismic response coefficient Cs is determined by Eq. 12.8-2 for values of T <_ 1.5Ts and taken as equal to 1.5 times the value computed in accordance with either Eq. 12.8-3 for TL >_ T > 1.5Ts or Eq. 12.8-4 for T > TL. • Structures on Site Class E sites with S� greater than or equal to 0.2, provided that T is less than or equal to Ts and the equivalent static force procedure is used for design. The above exceptions do not apply to seismically isolated structures, structures with damping systems or structures designed using the response history procedures of Chapter 16. Liquefaction is a phenomenon where there is a reduction or complete loss of soil strength due to an increase in water pressure induced by vibrations from a seismic event. low 1 LU RILEYGRUUP Geotechnical Engineering Report 4 June 17, 2021 Housing Hope Edmonds, Edmonds, Washington RGI Project No. 2021-319-1 Liquefaction mainly affects geologically recent deposits of fine-grained sands that are below the groundwater table. Soils of this nature derive their strength from intergranular friction. The generated water pressure or pore pressure essentially separates the soil grains and eliminates this intergranular friction, thus reducing or eliminating the soil's strength. RGI reviewed the soil conditions encountered during field exploration and assessed the potential for liquefaction of the site's soil during an earthquake. Because the site is underlain by glacial till, RGI considers that the possibility of liquefaction during an earthquake is minimal 4.6 GEOLOGIC HAZARD AREAS Regulated geologically hazardous areas include erosion, landslide, earthquake, or other geological hazards. Based on the conditions observed on the site, the site does not contain geologically hazardous areas. 5.0 Discussion and Recommendations 5.1 GEOTECHNICAL CONSIDERATIONS Based on our study, the site is suitable for the proposed construction from a geotechnical standpoint. RGI recommends that the proposed building be supported on spread footings bearing on medium dense native soil or structural fill. Detailed recommendations regarding the above issues and other geotechnical design considerations are provided in the following sections. These recommendations should be incorporated into the final design drawings and construction specifications. 5.2 EARTHWORK RGI expects that site grading will consist of shallow cuts and fills to achieve building and pavement grades and excavation for utilities including storm, water, sanitary sewer, and other utilities. 5.2.1 EROSION AND SEDIMENT CONTROL Potential sources or causes of erosion and sedimentation depend on construction methods, slope length and gradient, amount of soil exposed and/or disturbed, soil type, construction sequencing and weather. The impacts on erosion -prone areas can be reduced by implementing an erosion and sedimentation control plan. The plan should be designed in accordance with applicable city and/or county standards. RGI recommends the following erosion control Best Management Practices (BMPs): low 1 L- RILEVOROUP Geotechnical Engineering Report 5 Housing Hope Edmonds, Edmonds, Washington June 17, 2021 RGI Project No. 2021-319-1 ➢ Scheduling site preparation and grading for the drier summer and early fall months and undertaking activities that expose soil during periods of little or no rainfall ➢ Establishing a quarry spall construction entrance ➢ Installing siltation control fencing or anchored straw or coir wattles on the downhill side of work areas ➢ Covering soil stockpiles with anchored plastic sheeting ➢ Revegetating or mulching exposed soils with a minimum 3-inch thickness of straw if surfaces will be left undisturbed for more than one day during wet weather or one week in dry weather ➢ Directing runoff away from exposed soils and slopes ➢ Decreasing runoff velocities with check dams, straw bales or coir wattles ➢ Confining sediment to the project site ➢ Inspecting and maintaining erosion and sediment control measures frequently (The contractor should be aware that inspection and maintenance of erosion control BMPs is critical toward their satisfactory performance. Repair and/or replacement of dysfunctional erosion control elements should be anticipated.) Permanent erosion protection should be provided by reestablishing vegetation using hydroseeding and/or landscape planting. Until the permanent erosion protection is established, site monitoring should be performed by qualified personnel to evaluate the effectiveness of the erosion control measures. Provisions for modifications to the erosion control system based on monitoring observations should be included in the erosion and sedimentation control plan. 5.2.2 EXCAVATIONS All temporary cut slopes associated with the site and utility excavations should be adequately inclined to prevent sloughing and collapse. The site soils consisted of very loose to dense silty sand with trace gravel. Accordingly, for excavations more than 4 feet but less than 20 feet in depth, the temporary side slopes should be laid back with a minimum slope inclination of 1-1/21-1:1 V (Horizontal:Vertical) in existing fill or 3/41-1:1V in glacial till. If there is insufficient room to complete the excavations in this manner, or excavations greater than 20 feet in depth are planned, using temporary shoring to support the excavations should be considered. For open cuts at the site, RGI recommends: ➢ No traffic, construction equipment, stockpiles or building supplies are allowed at the top of cut slopes within a distance of at least 5 feet from the top of the cut. ➢ Exposed soil along the slope is protected from surface erosion using waterproof tarps and/or plastic sheeting. Geotechnical Engineering Report 6 June 17, 2021 Housing Hope Edmonds, Edmonds, Washington RGI Project No. 2021-319-1 ➢ Construction activities are scheduled so that the length of time the temporary cut is left open is minimized. ➢ Surface water is diverted away from the excavation. ➢ The general condition of slopes should be observed periodically by a geotechnical engineer to confirm adequate stability and erosion control measures. In all cases, however, appropriate inclinations will depend on the actual soil and groundwater conditions encountered during earthwork. Ultimately, the site contractor must be responsible for maintaining safe excavation slopes that comply with applicable OSHA or WISHA guidelines. 5.2.3 STRIPPING AND SITE PREPARATION Stripping efforts should include removal of pavements, vegetation, organic materials, and deleterious debris from areas slated for building, pavement, and utility construction. Based on the test pit exploration, approximately 12 inches of top soil needs to be stripped off in the building pad area. RGI anticipates that some areas of loose soil may be present on the site after stripping operations are complete. Prior to placement of structural fill, RGI recommends proofrolling building and pavement subgrades and areas to receive structural fill. These areas should be proofrolled under the observation of RGI and compacted to a firm and unyielding condition in order to achieve a minimum compaction level of 95 percent of the modified proctor maximum dry density as determined by the American Society of Testing and Materials D1557-09 Standard Test Methods for Laboratory Compaction Characteristics of Soil Using Modified Effort (ASTM D1557). Proofrolling and adequate subgrade compaction can only be achieved when the soils are within approximately ± 2 percent moisture content of the optimum moisture content. Soils may be proofrolled with a heavy compactor, loaded double -axle dump truck, or other heavy equipment under the observation of a RGI representative. This observer will assess the subgrade conditions prior to filling. Subgrade soils that become disturbed due to elevated moisture conditions should be overexcavated to reveal firm, non -yielding, non -organic soils and backfilled with compacted structural fill. In order to maximize utilization of site soils as structural fill, RGI recommends that the earthwork portion of this project be completed during extended periods of warm and dry weather, if possible. If earthwork is completed during the wet season (typically November through May) it will be necessary to take extra precautionary measures to protect subgrade soils. Wet season earthwork will require additional mitigative measures beyond what would be expected during the drier summer and fall months. Geotechnical Engineering Report 7 Housing Hope Edmonds, Edmonds, Washington June 17, 2021 RGI Project No. 2021-319-1 5.2.4 STRUCTURAL FILL Once site preparation is complete, cuts and fills can be made to establish desired building grades. Prior to placing fill, RGI recommends proof -rolling as described above. RGI recommends fill below the foundation and floor slab, behind retaining walls, and below pavement and hardscape surfaces be placed in accordance with the following recommendations for structural fill. The suitability of excavated site soils and import soils for compacted structural fill use will depend on the gradation and moisture content of the soil when it is placed. As the amount of fines (that portion passing the U.S. No. 200 sieve) increases, soil becomes increasingly sensitive to small changes in moisture content and adequate compaction becomes more difficult or impossible to achieve. Soils containing more than about 5 percent fines cannot be consistently compacted to a dense, non -yielding condition when the moisture content is more than 2 percent above or below optimum. Optimum moisture content is the moisture that results in the greatest compacted dry density with a specified compactive effort. The onsite excavated soils may be suitable for use as structural fill if the moisture can be properly controlled at the time of compaction. If the construction occurs in winter or extended to wet season, it may be necessary to import clean, granular soils to complete site work that meets the grading requirements listed in Table 2. Table 2 Structural Fill Gradation U.S. Sieve Size 4 inches inch No. 4 No. 200 *Based on minus 3/4 inch fraction. Percent Passing 100 70 minimum 35 to 60 0to5* Prior to use, a RGI representative should observe and test all materials imported to the site for use as structural fill. Structural fill materials should be placed in uniform loose layers not exceeding 12 inches and compacted as specified in Table 3. The soil's maximum density and optimum moisture should be determined by ASTM D1557. low 1 LM RILEVOROUP Geotechnical Engineering Report 8 Housing Hope Edmonds, Edmonds, Washington June 17, 2021 RGI Project No. 2021-319-1 Table 3 Structural Fill Compaction ASTM D1557 Location Minimum Material Type Compaction Percentage Moisture Content Range Foundations On -site granular or approved 95 +2 -2 imported fill soils Retaining Wall Backfill On -site granular or approved 92 +2 2 imported fill soils Slab -on -grade On -site granular or approved 95 +2 -2 imported fill soils General Fill (non- On -site granular or approved 90 +3 -2 structural areas) imported fill soils Pavement, Subgrade On -site granular or approved 95 +2 -2 and Base Course imported fill soils Placement and compaction of structural fill should be observed by RGI. A representative number of in -place density tests should be performed as the fill is being placed to confirm that the recommended level of compaction is achieved. 5.2.5 CUT AND FILL SLOPES All permanent cut and fill slopes should be graded with a finished inclination no greater than 2H:1V. Interior slopes of detention pond should be graded to 3H:1V. Upon completion of construction, the slope face should be trackwalked, compacted and vegetated, or provided with other physical means to guard against erosion. All fill placed for slope construction should meet the structural fill requirements as described in Section 5.2.4. Final grades at the top of the slopes must promote surface drainage away from the slope crest. Water must not be allowed to flow in an uncontrolled fashion over the slope face. If it is necessary to direct surface runoff towards the slope, it should be controlled at the top of the slope, piped in a closed conduit installed on the slope face, and taken to an appropriate point of discharge beyond the toe of the slope. 5.3 FOUNDATIONS Following site preparation and grading, the proposed building foundations may be supported on conventional spread footings bearing on medium dense native soil. Perimeter foundations exposed to weather should be at a minimum depth of 18 inches below final exterior grades. Interior foundations can be constructed at any convenient depth below the floor slab. Finished grade is defined as the lowest adjacent grade within low 1 LU RILEYG?0UP Geotechnical Engineering Report 9 June 17, 2021 Housing Hope Edmonds, Edmonds, Washington RGI Project No. 2021-319-1 5 feet of the foundation for perimeter (or exterior) footings and finished floor level for interior footings. Table 4 Foundation Design Design Parameter Value Allowable Bearing Capacity — Medium dense native soil 4,000 psfl Friction Coefficient 0.3 Passive pressure (equivalent fluid pressure) 250 pcf2 Minimum foundation dimensions Columns: 24 inches Walls: 16 inches 1 psf = pounds per square foot 2 pcf = pounds per cubic foot The allowable foundation bearing pressures apply to dead loads plus design live load conditions. For short-term loads, such as wind and seismic, a 1/3 increase in this allowable capacity may be used. At perimeter locations, RGI recommends not including the upper 12 inches of soil in the computation of passive pressures because it can be affected by weather or disturbed by future grading activity. The passive pressure value assumes the foundation will be constructed neat against competent soil or backfilled with structural fill as described in Section 5.2.4. The recommended base friction and passive resistance value includes a safety factor of about 1.5. With spread -footing foundations designed in accordance with the recommendations in this section, maximum total and differential post -construction settlements of 1 inch and 1/2 inch, respectively, should be expected. 5.4 RETAINING WALL If retaining walls are needed for a detention vault or site retaining walls, RGI recommends cast -in -place concrete walls be used. The retaining wall must be supported on firm native soil or structural fill. The magnitude of earth pressure development on retaining walls will partly depend on the quality of the wall backfill. RGI recommends placing and compacting wall backfill as structural fill. Wall drainage will be needed behind the wall face. A typical retaining wall drainage detail is shown on Figure 3. The retaining wall foundation subgrade should be supported on competent native soil. With wall backfill placed and compacted as recommended, and drainage properly installed, RGI recommends using the values in the following table for design. o 1 LU RILEY GP0UP Geotechnical Engineering Report 10 Housing Hope Edmonds, Edmonds, Washington June 17, 2021 RGI Project No. 2021-319-1 Table 5 Retaining Wall Design Design Parameter Value Allowable Bearing Capacity 4,000 psf Active Earth Pressure (unrestrained walls) 35 pcf At -rest Earth Pressure (restrained walls) 50 pcf For seismic design, an additional uniform load of 7 times the wall height (H) for unrestrained walls and 14H for restrained walls should be applied to the wall surface. Friction at the base of foundations and passive earth pressure will provide resistance to these lateral loads. Values for these parameters are provided in the Section 5.3. 5.5 SLAB -ON -GRADE CONSTRUCTION Once site preparation has been completed as described in Section 5.2, suitable support for slab -on -grade construction should be provided. The native soil subgrade should be medium dense native soil. Immediately below the floor slab, RGI recommends placing a 4- inch-thick capillary break layer of clean, free -draining pea gravel, washed rock, or crushed rock that has less than 5 percent passing the U.S. No. 200 sieve. This material will reduce the potential for upward capillary movement of water through the underlying soil and subsequent wetting of the floor slab. For the anticipated floor slab loading, we estimate post -construction floor settlements of %- to %-inch. For thickness design of the slab subjected to point loading from storage racks, RGI recommends using a subgrade modulus (Ks) of 150 pounds per square inch per inch of deflection. 5.6 DRAINAGE 5.6.1 SURFACE Final exterior grades should promote free and positive drainage away from the building area. Water must not be allowed to pond or collect adjacent to foundations or within the immediate building area. For non -pavement locations, RGI recommends providing a minimum drainage gradient of 3 percent for a minimum distance of 10 feet from the building perimeter. In paved locations, a minimum gradient of 1 percent should be provided unless provisions are included for collection and disposal of surface water adjacent to the structure. low 1 LM RILEVOROUP Geotechnical Engineering Report 11 Housing Hope Edmonds, Edmonds, Washington June 17, 2021 RGI Project No. 2021-319-1 5.6.2 SUBSURFACE RGI recommends installing perimeter foundation drains, details shown on Figure 3. The foundation drains and roof downspouts should be tightlined separately to an approved discharge facility. Subsurface drains must be laid with a gradient sufficient to promote positive flow to a controlled point of approved discharge. Considering the native soil is fairly permeable, the footing drain may be eliminated in area covered by sidewalk or pavement. 5.6.3 INFILTRATION A small scale Pilot Infiltration Test (PIT) was conducted to assess any infiltration potential in the native soils. The PIT test was conducted at a depth of approximately 3.5 feet below grade in test pit TP-1 which is in the northeastern portion of the site. Water was introduced into the pit until approximately twelve inches of water was standing in the bottom of the pit. The water supply was shut off and the water level was observed for approximately one hour. The water level was observed to be the same after one hours and the test was terminated. Based on the results of the PIT test, the native soil was determined to have no infiltration potential. 5.7 UTILITIES Utility pipes should be bedded and backfilled in accordance with American Public Works Association (APWA) specifications. For site utilities located within the right-of-ways, bedding and backfill should be completed in accordance with City of Edmonds specifications. At a minimum, trench backfill should be placed and compacted as structural fill, as described in Section 5.2.4. Where utilities occur below unimproved areas, the degree of compaction can be reduced to a minimum of 90 percent of the soil's maximum density as determined by ASTM D1557. The native soils may be used as backfill provided they can be adequately moisture conditioned and compacted in dry weather condition. Imported structural fill may be required for trench backfill in winter. 5.8 PAVEMENTS Pavement subgrades should be prepared as described in Section 5.2 of this GER and as discussed below. Regardless of the relative compaction achieved, the subgrade must be firm and relatively unyielding before paving. This condition should be verified by proofrolling with heavy construction equipment or hand probe by inspector. With the pavement subgrade prepared as described above, RGI recommends the following pavement sections for parking and drive areas paved with flexible asphalt concrete surfacing. ➢ For general parking areas: 3 inches of HMA over 6 inches of CRB over firm native soil Geotechnical Engineering Report 12 June 17, 2021 Housing Hope Edmonds, Edmonds, Washington RGI Project No. 2021-319-1 The asphalt paving materials used should conform to the Washington State Department of Transportation (WSDOT) specifications for Hot Mix Asphalt Class 1/2 inch and CRB surfacing. Long-term pavement performance will depend on surface drainage. A poorly -drained pavement section will be subject to premature failure as a result of surface water infiltrating into the subgrade soils and reducing their supporting capability. For optimum pavement performance, surface drainage gradients of no less than two percent are recommended. Also, some degree of longitudinal and transverse cracking of the pavement surface should be expected over time. Regular maintenance should be planned to seal cracks when they occur. 6.0 Additional Services RGI is available to provide further geotechnical consultation throughout the design phase of the project. RGI should review the final design and specifications in order to verify that earthwork and foundation recommendations have been properly interpreted and incorporated into project design and construction. RGI is also available to provide geotechnical engineering and construction monitoring services during construction. The integrity of the earthwork and construction depends on proper site preparation and procedures. In addition, engineering decisions may arise in the field in the event that variations in subsurface conditions become apparent. Construction monitoring services are not part of this scope of work. If these services are desired, please let us know and we will prepare a proposal. 7.0 Limitations This GER is the property of RGI, Housing Hope, and their designated agents. Within the limits of the scope and budget, this GER was prepared in accordance with generally accepted geotechnical engineering practices in the area at the time this report was issued. This GER is intended for specific application to the proposed Housing Hope Edmonds project at 82XX 236th Street Southwest in Edmonds, Washington, and for the exclusive use of Housing Hope and its authorized representatives. No other warranty, expressed or implied, is made. Site safety, excavation support, and dewatering requirements are the responsibility of others. The scope of services for this project does not include either specifically or by implication any environmental or biological (for example, mold, fungi, bacteria) assessment of the site or identification or prevention of pollutants, hazardous materials, or conditions. If the owner is concerned about the potential for such contamination or pollution, we can provide a proposal for these services. Geotechnical Engineering Report 13 Housing Hope Edmonds, Edmonds, Washington June 17, 2021 RGI Project No. 2021-319-1 The analyses and recommendations presented in this GER are based upon data obtained from the exploration performed on site. Variations in soil conditions can occur, the nature and extent of which may not become evident until construction. If variations appear evident, RGI should be requested to reevaluate the recommendations in this GER prior to proceeding with construction. It is the client's responsibility to see that all parties to the project, including the designers, contractors, subcontractors, are made aware of this GER in its entirety. The use of information contained in this GER for bidding purposes should be done at the contractor's option and risk. low 1 LM RILEY(:R0UP -J CL LW 22TH-ST-SW ' 04267-1 w Esperanc ' L LLJ 3TH,ST-S 6 O -SW o 00 99 104 LW �Srl NO 2361 H ST SW T, I 240TH ST S 242ND ST SW 205TH ST- N 205TH ST NW 205TH-ST V ST N 2Q0TH ST T USGS, 2020, Edmonds East, Washington Approximate Scale: 1"=1000' A 7.5-Minute Quadrangle 0 500 1000 2600 N Corporate Office Housing Hope at Edmonds T- Figure 1 a 17522 Bothell Way Northeast LWpBothell, Washington 98011 Phone: 425.415.0551 RGI Project Number: 2021-319-1 Site Vicinity Map Date Drawn: 06/2021 FULEYGROUFFax: 425.415.0311 Address: 82XX 236th Street Southwest, Edmonds, Washington 98026 I 15 _ S A�L ABI.- + _ 10' RO_SET CK STEP BACK IF>25'HEI TP-6-----_� I I I I I I---f--t------------------------- 20 I STEP-€ (E) BLOCKABLE�--L—��—� I 223 SFI2 UNDER €ILDG. B ,13T/ ;- 1. PARKIP,4G (6)/ / < BIKE IMF RTS rI GROUN FLOOR a 7,82 SF 1RT BD OFFI () r¢° 816 F/2 B - I 1 1,053 SF 13 913 - - ---- I", H ES JE Imo_-JILINA 0IN I aK _ BIKE BIKE BIKE I OT A 1 ❑❑❑❑❑ 5�f VCR SF I OILET MI- 6'X14' LAUNORV 22'X14' C --- BIKE BIK I BIKE Ti -RDD I, 1 I CHILORENB --- ; P ROOM = I 1 I 1 NEC STOR i I I <.UNDEFt B'XB J LRGW..I 1 I I ILET I PARKIN Q= KITCHEN X1B' I 6 �I m Pinzn n �22 moR. 4—J 04 BXr OILEf CURE I COURTYARD r ` L J l I I LL COMMUNRY IMULTIPURPOS ILE TP-4',X,a ; I Y Ua I avxa4' , 4, 4. PAR I I I A.1ORK I 0) I ADMIN./ ---4 I I I I OMMUNITY I 5,832SF� - 14- ; ; j IRE o T.n I I 12'%14El G V% F HEALTH ERVK;E BLDG. GE ABOVE GROUN FLOOR 0 T _ J R PAN'4RV 14'X9.5' 2X,5 X CE r Co�.� �; L ] 5,05 SF w — —, (3) 600 F / 1 BD ERVICE 14' 1 --ERVICE — �— X 1.5' --L ---------- MI . --- --- o 50/o FACAD ___ 10'STR ET 9414] SETBA K o— v o r, y = Test pit by RGI, 06/02/21 Approximate Scale: 1"=40' — — — = Site boundary 0 20 40 80 N Corporate Office Housing Hope at Edmonds Figure 2 17522 Bothell Way Northeast LW Bothell, Washington 98011 r Phone: 425.415.0551 11 LG Fax: 425.415.0311 RGI Project Number: 2021-319-1 Geotechnical Exploration Plan Date Drawn: 06/2021 Address: 82XX 236th Street Southwest, Edmonds, Washington 98026 12" Minimum Wide Free -Draining Gravel Slope to Drain 12" min. 000 coo: I' °00 dO i 0 .0... o O ... :;.°p0 _ . 00 .. Filter Fabric Material ::::: o0 c Excavated Slope (See Report for 00 00, Appropriate 0° i Incliniations) °° I- Compacted Structural ° Backfill (Native or Import) 0G0 o 00 00 ° ° °o °o°° 0 0 00.000 0 0 0. 0 0 0 °° 00 12" Over the Pipe 3" Below the Pipe e Diameter PVC p Perforated Pipe Not to Scale Corporate Office Housing Hope at Edmonds Figure 3 17522 Bothell Way Northeast RGI Project Number: Date Drawn: Bothell, Washington 98011 Retaining Wall Drainage Detail LG1 rV Phone: 425.415.0551 2021-319-1 06�2021 I Fax: 425.415.0311 Address: 82XX 236th Street Southwest, Edmonds, Washington 98026 Building Slab J ° O. •A 4" Perforated Pipe 3/4" Washed Rock or Pea Gravel Not to Scale Filter Fabric J Corporate Office Housing Hope at Edmonds Figure 4 17522 Bothell Way Northeast RGI Project Number: Date Drawn: Bothell, Washington 98011 Typical Footing Drain Detail LG1 rV Phone: 425.415.0551 2021-319-1 06/2021 I Fax: 425.415.0311 Address: 82XX 236th Street Southwest, Edmonds, Washington 98026 Geotechnical Engineering Report June 17, 2021 Housing Hope Edmonds, Edmonds, Washington RGI Project No. 2021-319-1 APPENDIX A FIELD EXPLORATION AND LABORATORY TESTING On June 2, 2021, RGI explored the subsurface soil conditions at the site by observing the excavation of six test pits to a maximum depth of 8.5 feet below existing grade. The test pit locations are shown on Figure 2. The test pit locations were approximately determined by measurements from existing property lines and paved roads. A geologist from our office conducted the field exploration and classified the soil conditions encountered, maintained a log of each exploration, obtained representative soil samples, and observed pertinent site features. All soil samples were visually classified in accordance with the Unified Soil Classification System (USCS). Representative soil samples obtained from the explorations were placed in closed containers and taken to our laboratory for further examination and testing. As a part of the laboratory testing program, the soil samples were classified in our in house laboratory based on visual observation, texture, and the limited laboratory testing described below. Moisture Content Determinations Moisture content determinations were performed in accordance with the American Society of Testing and Materials D2216-10 Standard Test Methods for Laboratory Determination of Water (Moisture) Content of Soil and Rock by Mass (ASTM D2216) on representative samples obtained from the exploration in order to aid in identification and correlation of soil types. The moisture content of typical sample was measured and is reported on the test pit logs. Grain Size Analysis A grain size analysis indicates the range in diameter of soil particles included in a particular sample. Grain size analyses for the greater than 75 micrometer portion of the samples were performed in accordance with American Society of Testing and Materials D422 Standard Test Method for Particle -Size Analysis of Soils (ASTM D422) on three of the samples, the results of which are attached in Appendix A. low 1 LU RILEY(:R0UP Project Name: Housing Hope Edmonds Test Pit No.: TP-1 Project Number: 2021-319-1 lk- Client: Housing Hope RILEYGRUUP Sheet 1 of 1 Date(s) Excavated: 6/2/2021 Logged By ELW Surface Conditions: Grass Excavation Method: Test Pit Bucket Size: N/A Total Depth of Excavation: 8.5 feet bgs Excavator Type: Rubber Tracked Excavator Excavating Contractor: Kelly's Excavating Approximate N/A Surface Elevation Groundwater Level: Not Encountered Sampling Grab Method(s) Compaction Method Bucket Test Pit Backfill: Cuttings Location 82XX 236th Street Southwest, Edmonds, Washington n E H Z T _J O O N to U L O O_ U) Q (6 w 0 <n U) D cD MATERIAL DESCRIPTION REMARKS AND OTHER TESTS 0 TPSL 101, topsoil sm Reddish brown silty SAND with some gravel, loose, moist Becomes medium dense 10% moisture sm Gray silty SAND with trace gravel, dense, moist (Glacial Till) 14% moisture, 33% fines s 13% moisture 10% moisture Test Pit terminated at 8.5' 1 The Riley Group, Inc. 17522 Bothell Way NE, Bothell, WA 98011 Project Name: Housing Hope Edmonds Test Pit No.: TP-2 Project Number: 2021-319-1 lk- Client: Housing Hope RILEYGROUP Sheet 1 of 1 Date(s) Excavated: 6/2/2021 Logged By ELW Surface Conditions: Grass Excavation Method: Test Pit Bucket Size: N/A Total Depth of Excavation: 5 feet bgs Excavator Type: Rubber Tracked Excavator Excavating Contractor: Kelly's Excavating Approximate N/A Surface Elevation Groundwater Level: Not Encountered Sampling Grab Method(s) Compaction Method Bucket Test Pit Backfill: Cuttings Location 82XX 236th Street Southwest, Edmonds, Washington n E H Z T to —J O O N U L O O_ U) Q (6 w 0 <n U) D cD MATERIAL DESCRIPTION REMARKS AND OTHER TESTS 0 TPSL 4" topsoil Fill Brown silty SAND with some gravel, medium dense, moist (Fill) SM P Reddish brown gravelly silty SAND, loose to medium dense, moist 10% moisture, 18% fines SM Gray silty SAND with some gravel, dense, moist (Glacial Till) 13% moisture 10% moisture 5 Test Pit terminated at 5' 1 The Riley Group, Inc. 17522 Bothell Way NE, Bothell, WA 98011 Project Name: Housing Hope Edmonds Test Pit No.: TP-3 Project Number: 2021-319-1 lk- Client: Housing Hope RILEYGRUUP Sheet 1 of 1 Date(s) Excavated: 6/2/2021 Logged By ELW Surface Conditions: Grass Excavation Method: Test Pit Bucket Size: N/A Total Depth of Excavation: 6.5 feet bgs Excavator Type: Rubber Tracked Excavator Excavating Contractor: Kelly's Excavating Approximate N/A Surface Elevation Groundwater Level: Not Encountered Sampling Grab Method(s) Compaction Method Bucket Test Pit Backfill: Cuttings Location 82XX 236th Street Southwest, Edmonds, Washington n E H Z T —J O O N to U L O O_ U) Q (6 w 0 <n U) D cD MATERIAL DESCRIPTION REMARKS AND OTHER TESTS 0 TPSL 5" topsoil Fill Brown silty SAND with some gravel, loose, moist (Fill) 13% moisture SM Reddish brown silty SAND with some gravel, medium dense, moist 16% moisture s SM Gray silty SAND with some gravel, dense, moist (Glacial Till) 14% moisture Test Pit terminated at 6.5' 1 The Riley Group, Inc. 17522 Bothell Way NE, Bothell, WA 98011 Project Name: Housing Hope Edmonds Test Pit No.: TP-4 Project Number: 2021-319-1 lk- Client: Housing Hope RILEYGRUUP Sheet 1 of 1 Date(s) Excavated: 6/2/2021 Logged By ELW Surface Conditions: Grass Excavation Method: Test Pit Bucket Size: N/A Total Depth of Excavation: 3.5 feet bgs Excavator Type: Rubber Tracked Excavator Excavating Contractor: Kelly's Excavating Approximate N/A Surface Elevation Groundwater Level: Not Encountered Sampling Grab Method(s) Compaction Method Bucket Test Pit Backfill: Cuttings Location 82XX 236th Street Southwest, Edmonds, Washington n E O H O Z N T to —J U L O O_ U) Q (6 w 0 <n U) D cD MATERIAL DESCRIPTION REMARKS AND OTHER TESTS 0 TPSL 6" topsoil SM Reddish brown silty SAND with some gravel, loose to medium dense, moist SM Gray silty SAND, dense, moist (Glacial Till) 21 % moisture, 49% fines Test Pit terminated at 3.5' 5- The Riley Group, Inc. 17522 Bothell Way NE, Bothell, WA 98011 Project Name: Housing Hope Edmonds Test Pit No.: TP-5 Project Number: 2021-319-1 lk- Client: Housing Hope RILEYGRUUP Sheet 1 of 1 Date(s) Excavated: 6/2/2021 Logged By ELW Surface Conditions: Grass Excavation Method: Test Pit Bucket Size: N/A Total Depth of Excavation: 4.5 feet bgs Excavator Type: Rubber Tracked Excavator Excavating Contractor: Kelly's Excavating Approximate N/A Surface Elevation Groundwater Level: Not Encountered Sampling Grab Method(s) Compaction Method Bucket Test Pit Backfill: Cuttings Location 82XX 236th Street Southwest, Edmonds, Washington n E H Z T —J O O N to U L O O_ U) Q (6 w 0 <n U) D cD MATERIAL DESCRIPTION REMARKS AND OTHER TESTS 0 SW-SM 7" topsoil Fill Brown silty SAND with some gravel, medium dense, moist Fill) race asphalt debris sM Reddish brown silty SAND with some gravel, medium dense, moist 13% moisture sM Gray silty SAND, dense, moist (Glacial Till) 22% moisture Test Pit terminated at 4.5' 5- The Riley Group, Inc. 17522 Bothell Way NE, Bothell, WA 98011 Project Name: Housing Hope Edmonds Test Pit No.: TP-6 Project Number: 2021-319-1 lk- Client: Housing Hope RILEYGRUUP Sheet 1 of 1 Date(s) Excavated: 6/2/2021 Logged By ELW Surface Conditions: Grass Excavation Method: Test Pit Bucket Size: N/A Total Depth of Excavation: 5.5 feet bgs Excavator Type: Rubber Tracked Excavator Excavating Contractor: Kelly's Excavating Approximate N/A Surface Elevation Groundwater Level: Not Encountered Sampling Grab Method(s) Compaction Method Bucket Test Pit Backfill: Cuttings Location 82XX 236th Street Southwest, Edmonds, Washington n E H Z T _J O O N to U L O O_ U) Q (6 w 0 <n U) D cD MATERIAL DESCRIPTION REMARKS AND OTHER TESTS 0 TPSL 101, topsoil Fill Brown silty SAND with some gravel, loose, moist Contains wood, concrete debris sm Reddish brown silty SAND with some gravel, medium dense, moist 16% moisture sm Gray silty SAND with trace gravel, dense, moist (Glacial Till) s 19% moisture Test Pit terminated at 5.5' 1 The Riley Group, Inc. 17522 Bothell Way NE, Bothell, WA 98011 Project Name: Housing Hope Edmonds Key to Logs Project Number: 2021-319-1 Client: Housing Hope RILEYGROUP Sheet 1 of 1 _ O - Q H O E Z N T W 0) _J U > a at E m E a1 U W n w o U)i W D C� COLUMN DESCRIPTIONS MATERIAL DESCRIPTION I REMARKS AND OTHER TESTS 1 Elevation (feet): Elevation (MSL, feet). 2 Depth (feet): Depth in feet below the ground surface. LIJ Sample Type: Type of soil sample collected at the depth interval shown. ® Sample Number: Sample identification number. FIELD AND LABORATORY TEST ABBREVIATIONS CHEM: Chemical tests to assess corrosivity COMP: Compaction test CONS: One-dimensional consolidation test LL: Liquid Limit, percent MATERIAL GRAPHIC SYMBOLS TYPICAL SAMPLER GRAPHIC SYMBOLS Auger sampler Bulk Sample Z3-inch-OD California w/ brass rings GENERAL NOTES CME Sampler Grab Sample 2.5-inch-OD Modified California w/ brass liners 5 USCS Symbol: USCS symbol of the subsurface material. L6J Graphic Log: Graphic depiction of the subsurface material encountered. �7 MATERIAL DESCRIPTION: Description of material encountered. May include consistency, moisture, color, and other descriptive text. ® REMARKS AND OTHER TESTS: Comments and observations regarding drilling or sampling made by driller or field personnel. PI: Plasticity Index, percent SA: Sieve analysis (percent passing No. 200 Sieve) UC: Unconfined compressive strength test, Qu, in ksf WA: Wash sieve (percent passing No. 200 Sieve) • • d��; Well graded SAND with Silt (SW-SM) Topsoil Pitcher Sample 2-inch-OD unlined split spoon (SPT) Shelby Tube (Thin -walled, fixed head) OTHER GRAPHIC SYMBOLS Water level (at time of drilling, ATD) • Water level (after waiting) _ Minor change in material properties within a v stratum — Inferred/gradational contact between strata — ? — Queried contact between strata 1: Soil classifications are based on the Unified Soil Classification System. Descriptions and stratum lines are interpretive, and actual lithologic changes may be gradual. Field descriptions may have been modified to reflect results of lab tests. 2: Descriptions on these logs apply only at the specific boring locations and at the time the borings were advanced. They are not warranted to be representative of subsurface conditions at other locations or times. The Riley Group, Inc. 17522 Bothell Way NE, Bothell, WA 98011 THE RILEY GROUP, INC. 17522 Bothell Way NE Bothell, WA 98011 PHONE: (425) 415-0551 FAX: (425) 415-0311 PROJECT TITLE Housing Hope Edmonds PROJECT NO. 2021-319-1 FECH/TEST DATE EW/CD WATER CONTENT (Delivered Moisture) Wt Wet Soil & Tare (gm) Wt Dry Soil & Tare (gm) Weight of Tare (gm) Weight of Water (gm) (w4=w1 Weight of Dry Soil (gm) (w5=w2 Moisture Content (%) (w4/w5) GRAIN SIZE ANALYSIS STM D421, D422, D1140, D2487, D6913 SAMPLE ID/TYPE TP-1 SAMPLE DEPTH 3.5' 6/2/2021 DATE RECEIVED 6/2/2021 Total Weight Of Sample Used For Sieve Corrected For Hygroscopic Moi Weight Of Sample (gm) 375.3 (w1) 426.4 15.8 (w2) 375.3 Tare Weight (gm) 359.5 (w3) 15.8 (W6) Total Dry Weight (gm) -w2) 51.1 SIEVE ANALYSIS -w3) 359.5 Cumulative *1001 14 Wt Ret Wt-Tare (%Retained) % PASS +Tare Rwtret/wW1001 (100%ret) • COBBLES 0.0 12.0" • C GRAVEL 0.0 3.0" % F GRAVEL 9.3 2.5" • C SAND 6.2 2.0" % M SAND 20.6 1.5" • F SAND 30.9 1.0" % FINES 33.0 0.75" • TOTAL 100.0 0.50" 0.375" D10 (mm) #4 D30 (mm) #10 D60 (mm) #20 Cu #40 Cc #60 100 90 80 P 70 A 60 S 50 40 S 30 1 20 N 10 0 #100 #200 PAN 15.8 0.00 0.00 100.00 15.8 0.00 0.00 100.00 15.8 0.00 0.00 100.00 15.8 0.00 0.00 100.00 24.9 9.10 2.53 97.47 49.1 33.30 9.26 90.74 71.4 55.60 15.47 84.53 145.4 129.60 36.05 63.95 221.5 205.70 j 57.22 j 42.78 256.6 240.80 66.98 33.02 375.3 359.50 100.00 0.00 12" 3" 2" 1".75" .375" #4 #10 #20 #40 #60 #100 #200 G 1000 100 10 1 Grain size in millimeters DESCRIPTION Silty SAND with trace gravel USCS SM Prepared For: Housing Hope Reviewed By: ELW cobbles coarse gravel coarse gravel coarse gravel coarse gravel coarse gravel fine gravel fine gravel fine gravel coarse sand medium sand medium sand fine sand fine sand fine sand fines silt/clay 0.1 0.01 0.001 mom ,_ RILEYGROUP THE RILEY GROUP, INC. 17522 Bothell Way NE Bothell, WA 98011 PHONE: (425) 415-0551 FAX: (425) 415-0311 II GRAIN SIZE ANALYSIS II ASTM D421, D422, D1140, D2487, D6913 PROJECT TITLE Housing Hope Edmonds PROJECT NO. 2021-319-1 TECH/TEST DATE EW/CD 6/2/20; WATER CONTENT (Delivered Moisture) Wt Wet Soil & Tare (gm) (w1) 353.9 Wt Dry Soil & Tare (gm) (w2) 324.0 Weight of Tare (gm) (w3) 15.5 Weight of Water (gm) (w4=w1-w2) 29.9 Weight of Dry Soil (gm) (w5=w2-w3) 308.5 Moisture Content (%) (w4/w5)*100 10 % COBBLES % C GRAVEL % F GRAVEL % C SAND % M SAND %FSAND % FINES % TOTAL D10 (mm) D30 (mm) D60 (mm) Cu CC 0.0 12.0' 3.0' 2.5' 2.0' 1.5' 1.0' 0.75' 0.50' 0.375' #4 #1C #2C #4C #6C 10.0 24.3 11.8 15.7 19.9 18.3 100.0 P A S S I N G #10C #20C PAN SAMPLE ID/TYPE TP-2 SAMPLE DEPTH 2' DATE RECEIVED 6/2/2021 tal Weight Of Sample Used For Sieve Corrected For Hygroscopic Mc Weight Of Sample (gm) 324.0 Tare Weight (gm) 15.5 (W6) Total Dry Weight (gm) 308.5 SIEVE ANALYSIS Cumulative Wt Ret (Wt-Tare) (%Retained) % PASS +Tare 1(wt ret/w6)*1001 (100-%ret) 15.5 0.00 0.00 100.00 15.5 0.00 0.00 100.00 15.5 0.00 0.00 100.00 46.3 30.80 9.98 90.02 90.6 75.10 24.34 75.66 121.2 105.70 34.26 65.74 157.6 142.10 46.06 53.94 206.1 190.60 61.78 38.22 254.2 238.70 77.37 22.63 267.6 252.10 81.72 18.28 324.0 308.50 100.00 0.00 12" 3" 2" 1".75 .375" #4 #10 #20 #40 #60 #100 #200 100 90 80 70 60 50 40 30 20 10 0 1000 100 10 1 Grain size in millimeters DESCRIPTION Gravelly silty SAND USCS SM Prepared For: Housing Hope Reviewed By: ELW -obbles -oarse gravel -oarse gravel -oarse gravel -oarse gravel -oarse gravel fine gravel fine gravel fine gravel -oarse sand -nedium sand -nedium sand fine sand fine sand fine sand fines silt/clay 0.1 0.01 0.001 mom ,- RILEYGROUP THE RILEY GROUP, INC. 17522 Bothell Way NE Bothell, WA 98011 PHONE: (425) 415-0551 FAX: (425) 415-0311 II GRAIN SIZE ANALYSIS II ASTM D421, D422, D1140, D2487, D6913 PROJECT TITLE Housing Hope Edmonds PROJECT NO. 2021-319-1 TECH/TEST DATE EW/CD 6/2/20; WATER CONTENT (Delivered Moisture) Wt Wet Soil & Tare (gm) (w1) 385.0 Wt Dry Soil & Tare (gm) (w2) 321.9 Weight of Tare (gm) (w3) 15.9 Weight of Water (gm) (w4=w1-w2) 63.1 Weight of Dry Soil (gm) (w5=w2-w3) 306.0 Moisture Content (%) (w4/w5)*100 21 % COBBLES % C GRAVEL % F GRAVEL % C SAND % M SAND % F SAND % FINES % TOTAL D10 (mm) D30 (mm) D60 (mm) Cu CC 0.0 12.0' 3.0' 2.5' 2.0' 1.5' 1.0' 0.75' 0.50' 0.375' #4 #1C #2C #4C #6C 0.0 3.5 2.7 21.5 22.9 49.4 100.0 P A S S I N G #10C #20C PAN SAMPLE ID/TYPE TP-4 SAMPLE DEPTH 3' DATE RECEIVED 6/2/2021 tal Weight Of Sample Used For Sieve Corrected For Hygroscopic Mc Weight Of Sample (gm) 321.9 Tare Weight (gm) 15.9 (W6) Total Dry Weight (gm) 306.0 SIEVE ANALYSIS Cumulative Wt Ret (Wt-Tare) (%Retained) % PASS +Tare 1(wt ret/wW1001 (100-%ret) 15.8 -0.10 -0.03 100.03 15.8 -0.10 -0.03 100.03 15.8 -0.10 -0.03 100.03 15.8 -0.10 -0.03 100.03 22.0 6.10 1.99 98.01 26.6 10.70 3.50 96.50 34.9 19.00 6.21 93.79 100.6 84.70 27.68 72.32 151.6 135.70 44.35 55.65 170.8 154.90 50.62 49.38 321.9 306.00 100.00 0.00 12" 3" 2" 1".75" .375" #4 #10 #20 #40 #60 #100 #200 100 90 80 70 60 50 40 30 20 10 0 1000 100 10 1 Grain size in millimeters DESCRIPTION Silty SAND USCS SM Prepared For: Housing Hope Reviewed By: ELW -obbles -oarse gravel -oarse gravel -oarse gravel -oarse gravel -oarse gravel fine gravel fine gravel fine gravel -oarse sand -nedium sand -nedium sand fine sand fine sand fine sand fines silt/clay 0.1 0.01 0.001 mom ,- RILEYGROUP