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HomeMy WebLinkAboutEx_12_RS_Geotech_Report_210804_v1EarthSolutionsNWLLC EarthSolutions NW LLC 15365 N.E.90th Street,Suite 100 Redmond,WA 98052 (425)449-4704 Fax (425)449-4711 www.earthsolutionsnw.com Geotechnical Engineering Construction Observation/Testing Environmental Services GEOTECHNICAL ENGINEERING STUDY HARRINGTON REDEVELOPMENT 960 HARRINGTON AVENUE NORTHEAST RENTON,WASHINGTON ES-7282 EXHIBIT 12 RECEIVED 08/30/2021 jding PLANNING DIVISION DocuSign Envelope ID: 9A2B0C09-72D8-490B-A60E-EAD24B2FAACB PREPARED FOR ZARNOOR ASSOCIATES, LLC c/o MR. KARIM KARMALI May 24, 2021 _________________________ Chase G. Halsen, L.G. Project Geologist _________________________ Keven D. Hoffmann, P.E. Geotechnical Engineering Services Manager GEOTECHNICAL ENGINEERING STUDY HARRINGTON REDEVELOPMENT 960 HARRINGTON AVENUE NORTHEAST RENTON, WASHINGTON ES-7282 Earth Solutions NW, LLC 15365 Northeast 90th Street, Suite 100 Redmond, Washington 98052 Phone: 425-449-4704 | Fax: 425-449-4711 www.earthsolutionsnw.com 05/24/2021 05/24/2021 DocuSign Envelope ID: 9A2B0C09-72D8-490B-A60E-EAD24B2FAACB Geotechnical-Engineering Report Important Information about This Subsurface problems are a principal cause of construction delays, cost overruns, claims, and disputes. While you cannot eliminate all such risks, you can manage them. The following information is provided to help. The Geoprofessional Business Association (GBA) has prepared this advisory to help you – assumedly a client representative – interpret and apply this geotechnical-engineering report as effectively as possible. In that way, you can benefit from a lowered exposure to problems associated with subsurface conditions at project sites and development of them that, for decades, have been a principal cause of construction delays, cost overruns, claims, and disputes. If you have questions or want more information about any of the issues discussed herein, contact your GBA-member geotechnical engineer. Active engagement in GBA exposes geotechnical engineers to a wide array of risk-confrontation techniques that can be of genuine benefit for everyone involved with a construction project. Understand the Geotechnical-Engineering Services Provided for this Report Geotechnical-engineering services typically include the planning, collection, interpretation, and analysis of exploratory data from widely spaced borings and/or test pits. Field data are combined with results from laboratory tests of soil and rock samples obtained from field exploration (if applicable), observations made during site reconnaissance, and historical information to form one or more models of the expected subsurface conditions beneath the site. Local geology and alterations of the site surface and subsurface by previous and proposed construction are also important considerations. Geotechnical engineers apply their engineering training, experience, and judgment to adapt the requirements of the prospective project to the subsurface model(s). Estimates are made of the subsurface conditions that will likely be exposed during construction as well as the expected performance of foundations and other structures being planned and/or affected by construction activities. The culmination of these geotechnical-engineering services is typically a geotechnical-engineering report providing the data obtained, a discussion of the subsurface model(s), the engineering and geologic engineering assessments and analyses made, and the recommendations developed to satisfy the given requirements of the project. These reports may be titled investigations, explorations, studies, assessments, or evaluations. Regardless of the title used, the geotechnical-engineering report is an engineering interpretation of the subsurface conditions within the context of the project and does not represent a close examination, systematic inquiry, or thorough investigation of all site and subsurface conditions. Geotechnical-Engineering Services are Performed for Specific Purposes, Persons, and Projects, and At Specific Times Geotechnical engineers structure their services to meet the specific needs, goals, and risk management preferences of their clients. A geotechnical-engineering study conducted for a given civil engineer will not likely meet the needs of a civil-works constructor or even a different civil engineer. Because each geotechnical-engineering study is unique, each geotechnical-engineering report is unique, prepared solely for the client. Likewise, geotechnical-engineering services are performed for a specific project and purpose. For example, it is unlikely that a geotechnical- engineering study for a refrigerated warehouse will be the same as one prepared for a parking garage; and a few borings drilled during a preliminary study to evaluate site feasibility will not be adequate to develop geotechnical design recommendations for the project. Do not rely on this report if your geotechnical engineer prepared it: • for a different client; • for a different project or purpose; • for a different site (that may or may not include all or a portion of the original site); or • before important events occurred at the site or adjacent to it; e.g., man-made events like construction or environmental remediation, or natural events like floods, droughts, earthquakes, or groundwater fluctuations. Note, too, the reliability of a geotechnical-engineering report can be affected by the passage of time, because of factors like changed subsurface conditions; new or modified codes, standards, or regulations; or new techniques or tools. If you are the least bit uncertain about the continued reliability of this report, contact your geotechnical engineer before applying the recommendations in it. A minor amount of additional testing or analysis after the passage of time – if any is required at all – could prevent major problems. Read this Report in Full Costly problems have occurred because those relying on a geotechnical- engineering report did not read the report in its entirety. Do not rely on an executive summary. Do not read selective elements only. Read and refer to the report in full. You Need to Inform Your Geotechnical Engineer About Change Your geotechnical engineer considered unique, project-specific factors when developing the scope of study behind this report and developing the confirmation-dependent recommendations the report conveys. Typical changes that could erode the reliability of this report include those that affect: • the site’s size or shape; • the elevation, configuration, location, orientation, function or weight of the proposed structure and the desired performance criteria; • the composition of the design team; or • project ownership. As a general rule, always inform your geotechnical engineer of project or site changes – even minor ones – and request an assessment of their impact. The geotechnical engineer who prepared this report cannot accept DocuSign Envelope ID: 9A2B0C09-72D8-490B-A60E-EAD24B2FAACB responsibility or liability for problems that arise because the geotechnical engineer was not informed about developments the engineer otherwise would have considered. Most of the “Findings” Related in This Report Are Professional Opinions Before construction begins, geotechnical engineers explore a site’s subsurface using various sampling and testing procedures. Geotechnical engineers can observe actual subsurface conditions only at those specific locations where sampling and testing is performed. The data derived from that sampling and testing were reviewed by your geotechnical engineer, who then applied professional judgement to form opinions about subsurface conditions throughout the site. Actual sitewide-subsurface conditions may differ – maybe significantly – from those indicated in this report. Confront that risk by retaining your geotechnical engineer to serve on the design team through project completion to obtain informed guidance quickly, whenever needed. This Report’s Recommendations Are Confirmation-Dependent The recommendations included in this report – including any options or alternatives – are confirmation-dependent. In other words, they are not final, because the geotechnical engineer who developed them relied heavily on judgement and opinion to do so. Your geotechnical engineer can finalize the recommendations only after observing actual subsurface conditions exposed during construction. If through observation your geotechnical engineer confirms that the conditions assumed to exist actually do exist, the recommendations can be relied upon, assuming no other changes have occurred. The geotechnical engineer who prepared this report cannot assume responsibility or liability for confirmation-dependent recommendations if you fail to retain that engineer to perform construction observation. This Report Could Be Misinterpreted Other design professionals’ misinterpretation of geotechnical- engineering reports has resulted in costly problems. Confront that risk by having your geotechnical engineer serve as a continuing member of the design team, to: • confer with other design-team members; • help develop specifications; • review pertinent elements of other design professionals’ plans and specifications; and • be available whenever geotechnical-engineering guidance is needed. You should also confront the risk of constructors misinterpreting this report. Do so by retaining your geotechnical engineer to participate in prebid and preconstruction conferences and to perform construction- phase observations. Give Constructors a Complete Report and Guidance Some owners and design professionals mistakenly believe they can shift unanticipated-subsurface-conditions liability to constructors by limiting the information they provide for bid preparation. To help prevent the costly, contentious problems this practice has caused, include the complete geotechnical-engineering report, along with any attachments or appendices, with your contract documents, but be certain to note conspicuously that you’ve included the material for information purposes only. To avoid misunderstanding, you may also want to note that “informational purposes” means constructors have no right to rely on the interpretations, opinions, conclusions, or recommendations in the report. Be certain that constructors know they may learn about specific project requirements, including options selected from the report, only from the design drawings and specifications. Remind constructors that they may perform their own studies if they want to, and be sure to allow enough time to permit them to do so. Only then might you be in a position to give constructors the information available to you, while requiring them to at least share some of the financial responsibilities stemming from unanticipated conditions. Conducting prebid and preconstruction conferences can also be valuable in this respect. Read Responsibility Provisions Closely Some client representatives, design professionals, and constructors do not realize that geotechnical engineering is far less exact than other engineering disciplines. This happens in part because soil and rock on project sites are typically heterogeneous and not manufactured materials with well-defined engineering properties like steel and concrete. That lack of understanding has nurtured unrealistic expectations that have resulted in disappointments, delays, cost overruns, claims, and disputes. To confront that risk, geotechnical engineers commonly include explanatory provisions in their reports. Sometimes labeled “limitations,” many of these provisions indicate where geotechnical engineers’ responsibilities begin and end, to help others recognize their own responsibilities and risks. Read these provisions closely. Ask questions. Your geotechnical engineer should respond fully and frankly. Geoenvironmental Concerns Are Not Covered The personnel, equipment, and techniques used to perform an environmental study – e.g., a “phase-one” or “phase-two” environmental site assessment – differ significantly from those used to perform a geotechnical-engineering study. For that reason, a geotechnical-engineering report does not usually provide environmental findings, conclusions, or recommendations; e.g., about the likelihood of encountering underground storage tanks or regulated contaminants. Unanticipated subsurface environmental problems have led to project failures. If you have not obtained your own environmental information about the project site, ask your geotechnical consultant for a recommendation on how to find environmental risk-management guidance. Obtain Professional Assistance to Deal with Moisture Infiltration and Mold While your geotechnical engineer may have addressed groundwater, water infiltration, or similar issues in this report, the engineer’s services were not designed, conducted, or intended to prevent migration of moisture – including water vapor – from the soil through building slabs and walls and into the building interior, where it can cause mold growth and material-performance deficiencies. Accordingly, proper implementation of the geotechnical engineer’s recommendations will not of itself be sufficient to prevent moisture infiltration. Confront the risk of moisture infiltration by including building-envelope or mold specialists on the design team. Geotechnical engineers are not building-envelope or mold specialists. Copyright 2019 by Geoprofessional Business Association (GBA). Duplication, reproduction, or copying of this document, in whole or in part, by any means whatsoever, is strictly prohibited, except with GBA’s specific written permission. Excerpting, quoting, or otherwise extracting wording from this document is permitted only with the express written permission of GBA, and only for purposes of scholarly research or book review. Only members of GBA may use this document or its wording as a complement to or as an element of a report of any kind. Any other firm, individual, or other entity that so uses this document without being a GBA member could be committing negligent or intentional (fraudulent) misrepresentation. Telephone: 301/565-2733 e-mail: info@geoprofessional.org www.geoprofessional.org DocuSign Envelope ID: 9A2B0C09-72D8-490B-A60E-EAD24B2FAACB May 24, 2021 ES-7282 Zarnoor Associates, LLC c/o Mr. Karim Karmali 19515 North Creek Parkway, Suite 314 Bothell, Washington 98011 Attention: Mr. Nazim Karmali Dear Mr. Karmali: Earth Solutions NW, LLC (ESNW) is pleased to present this geotechnical report to support the design and construction of the proposed mixed-use development, currently known as the Harrington Redevelopment. Based on the results of our investigation, the proposed redevelopment is feasible from a geotechnical standpoint. Our study indicates the site is underlain primarily by dense to very dense glacial till. Based on our findings, the proposed mixed-use structure may be constructed on a conventional continuous and spread footing foundations bearing upon competent native soil, recompacted native soil, or new structural fill placed directly on competent native soil. Competent native soil suitable for support of the proposed building will likely be encountered beginning at depths of about two-and-one-half to five feet below existing grades across most of the site. Soil in the northwest site corner was characterized as loose to medium dense during the field exploration; accordingly, areas of native soil may need to be either mechanically recompacted or overexcavated and replaced with suitable structural fill to establish competent and uniform soil bearing conditions. In general, where loose or unsuitable soil conditions are exposed at foundation subgrade elevations, compaction of the soil to the specifications of structural fill or overexcavation and replacement with suitable structural fill will be necessary. Full infiltration is not recommended from a geotechnical standpoint given the predominance of dense silty sand encountered across most of the site. Sandier soils encountered near the northwest site corner may prove feasible for limited, targeted infiltration. However, any design would need to incorporate provisions for overflow. If infiltration is pursued, ESNW should be contacted to provide supplementary consulting and testing services. Pertinent geotechnical recommendations are provided in this study. We appreciate the opportunity to be of service to you on this project. If you have any questions regarding the content of this geotechnical engineering study, please call. Sincerely, EARTH SOLUTIONS NW, LLC Chase G. Halsen, L.G. Project Geologist 15365 N.E. 90th Street, Suite 100 • Redmond, WA 98052 •(425) 449-4704 • FAX (425) 449-4711 Earth Solutions NW LLC Geotechnical Engineering, Construction Observation/Testing and Environmental Services DocuSign Envelope ID: 9A2B0C09-72D8-490B-A60E-EAD24B2FAACB Earth Solutions NW, LLC Table of Contents ES-7282 PAGE INTRODUCTION ................................................................................. 1 General..................................................................................... 1 Project Description ................................................................. 2 SITE CONDITIONS ............................................................................. 2 Surface ..................................................................................... 2 Subsurface .............................................................................. 2 Topsoil and Fill ............................................................. 3 Native Soil ..................................................................... 3 Geologic Setting ........................................................... 3 Groundwater ................................................................. 3 Critical Areas Review ............................................................. 4 DISCUSSION AND RECOMMENDATIONS ....................................... 4 General..................................................................................... 4 Site Preparation and Earthwork ............................................. 4 Temporary Erosion Control ......................................... 4 Excavations and Slopes .............................................. 5 In-situ and Imported Soil ............................................. 5 Subgrade Preparation .................................................. 6 Wet Season Grading…………………………………...... 6 Structural Fill ................................................................ 6 Foundations ............................................................................ 7 Seismic Design ....................................................................... 8 Slab-on-Grade Floors ............................................................. 9 Retaining Walls ....................................................................... 9 Drainage................................................................................... 10 Preliminary Infiltration Feasibility ............................... 10 Utility Support and Trench Backfill ....................................... 10 LIMITATIONS ...................................................................................... 11 Additional Services ................................................................. 11 DocuSign Envelope ID: 9A2B0C09-72D8-490B-A60E-EAD24B2FAACB Earth Solutions NW, LLC Table of Contents Cont’d ES-7282 GRAPHICS Plate 1 Vicinity Map Plate 2 Boring Location Plan Plate 3 Retaining Wall Drainage Detail Plate 4 Footing Drain Detail APPENDICES Appendix A Subsurface Exploration Boring Logs Appendix B Laboratory Test Results DocuSign Envelope ID: 9A2B0C09-72D8-490B-A60E-EAD24B2FAACB Earth Solutions NW, LLC GEOTECHNICAL ENGINEERING STUDY HARRINGTON REDEVELOPMENT 960 HARRINGTON AVENUE NORTHEAST RENTON, WASHINGTON ES-7282 INTRODUCTION General This geotechnical engineering study (study) was prepared for the proposed mixed-use project (currently referred to as the Harrington Redevelopment), to be constructed directly southeast of the intersection between Northeast Sunset Boulevard and Harrington Avenue Northeast, in Renton, Washington. This study was prepared to provide geotechnical recommendations for currently proposed development plans and included the following geotechnical services:  Borings to characterize soil and groundwater conditions.  Laboratory testing of representative soil samples collected at the boring locations.  Engineering analyses. The following documents and maps were reviewed as part of our study preparation:  Feasibility Study for Revised Options – Surface Parking, prepared by Grouparchitect, dated August 10, 2020.  Conceptual Site Plan for 25% Schematic Design, prepared by Grouparchitect, dated February 4, 2021.  ALTA/NSPS Land Title Survey, prepared by Axis Survey & Mapping, Inc., dated January 7, 2020.  Online Web Soil Survey (WSS) resource, maintained by the Natural Resources Conservation Service (NRCS) under the United States Department of Agriculture (USDA).  Geologic Map of the Renton Quadrangle, Washington, prepared by D.R. Mullineaux, 1965.  Chapter 3, Title IV of the Renton Municipal Code. DocuSign Envelope ID: 9A2B0C09-72D8-490B-A60E-EAD24B2FAACB Zarnoor Associates, LLC ES-7282 c/o Mr. Karim Karmali Page 2 May 24, 2021 Earth Solutions NW, LLC Project Description We understand the project is pursing construction of a six-story, mixed-use structure and associated site improvements. The at-grade level will include a parking garage, retail space, and residential accessories, and levels two through six will be apartments. Site ingress and egress will be provided by Northeast Sunset Boulevard. At the time of report submission, specific building load plans were not available for review. Based on our experience with similar developments, the proposed structure will utilize a concrete podium for at-grade level construction, with lightly loaded wood farming above. Perimeter footing loads will likely be about 5 to 6 kips per lineal foot. Slab-on-grade loading is anticipated to be approximately 150 pounds per square foot (psf). We anticipate grade modifications (cuts or fills) of less than five feet will be necessary to establish design elevations. If the above design assumptions either change or are incorrect, ESNW should be contacted to review the recommendations provided in this report. ESNW should review final designs to confirm that appropriate geotechnical recommendations have been incorporated into the plans. SITE CONDITIONS Surface The subject site is located at the southeast corner of the Northeast Sunset Boulevard and Harrington Avenue Northeast intersection, in Renton, Washington. The approximate site location is depicted on Plate 1 (Vicinity Map). The irregularly shaped site consists of King County Parcel No. 722780-1025, totaling about 0.67 acres. The site is bordered to the north by Northeast Sunset Boulevard, to the east by a Safeway grocery store and parking lot, to the south by an apartment building, and to the west by Harrington Avenue Northeast. The existing topography descends to the southwest, with about six to eight feet of elevation change across the subject site. The site is currently developed with two restaurants (Subway and Pizza Hut) and associated improvements. Most of the site is surfaced with asphalt. Subsurface An ESNW representative observed, logged, and sampled the advancement of three soil borings on February 12, 2021. The borings were completed within accessible areas of the property using a drill rig and operators retained by our firm. The approximate locations of the borings are depicted on Plate 2 (Boring Location Plan). Please refer to the boring logs provided in Appendix A for a more detailed description of subsurface conditions. Representative soil samples collected at the boring locations were analyzed in general accordance with both Unified Soil Classification System (USCS) and USDA methods and procedures. DocuSign Envelope ID: 9A2B0C09-72D8-490B-A60E-EAD24B2FAACB Zarnoor Associates, LLC ES-7282 c/o Mr. Karim Karmali Page 3 May 24, 2021 Earth Solutions NW, LLC Topsoil and Fill Topsoil was not encountered at the boring locations. Given the existing level of development, significant amount of topsoil is not expected across the site. Silty sand fill was encountered at B-2, extending to a depth of about four-and-one-half feet below the existing ground surface (bgs). The fill was characterized as very loose and moist. As stated above, asphalt covers most of the ground surface across the site. Asphalt thicknesses were about one to two inches at the boring locations. Native Soil Native site soil encountered at the boring locations consisted primarily of silty sand (USCS: SM). Localized areas of poorly graded sand with silt and well-graded sand with silt (USCS: SP-SM and SW-SM) were encountered at B-3. Native soils were primarily observed in a medium dense to very dense and moist condition and generally exhibited an increasingly dense condition with depth. However, the approximate upper 10 feet of soil encountered at B-3 was characterized as loose to medium dense. Each boring location was terminated in very dense native soil and extended to a maximum exploration depth of about 26.5 feet bgs. Geologic Setting The referenced geologic map resource identifies ground moraine deposits (Qgt) as underlying the site and adjacent areas. Ground moraine deposits, otherwise known as glacial till, are considered an unsorted mixture of sand, silt, clay, and gravel. The referenced WSS resource identifies soils of the Ragnar-Indianola association and Urban land designations across the site and immediately adjacent areas. The Ragnar-Indianola associations is representative of kame, terrace, and eskers landforms, while designations of Urban land suggest historic earthwork activities and grade modifications in the area. Based on the encountered conditions, native soils are generally considered representative of ground moraine (glacial till) deposits in accordance with local geologic mapping. Groundwater Minor perched groundwater seepage was exposed at a depth of about 10 feet bgs within B-1. Zones of perched groundwater seepage should be expected during general earthwork activities and will likely develop within the soil substratum depending on the time of year. Seepage rates and elevations fluctuate depending on many factors, including precipitation duration and intensity, the time of year, and soil conditions. In general, groundwater flow rates are higher during the winter, spring, and early summer months. DocuSign Envelope ID: 9A2B0C09-72D8-490B-A60E-EAD24B2FAACB Zarnoor Associates, LLC ES-7282 c/o Mr. Karim Karmali Page 4 May 24, 2021 Earth Solutions NW, LLC Critical Areas Review The City of Renton GIS mapping application and Chapter 3, Title IV of the Renton Municipal Code were reviewed to evaluate the presence of jurisdictionally recognized geologic hazards on site or on immediately adjacent parcels. Review of these applications did not indicate the presence of any jurisdictionally recognized geologic hazards in the area. In addition, we did not observe any obvious indication of the presence of these hazards at surface grades or within the boring locations. DISCUSSION AND RECOMMENDATIONS General Based on the results of our investigation, construction of the proposed residential development is feasible from a geotechnical standpoint. The primary geotechnical considerations for the proposal are in reference to structural fill placement and compaction, established a suitable subgrade to support the proposed mixed-use structure, foundation design, and stormwater management recommendations. Site Preparation and Earthwork Initial site preparation activities will consist of installing temporary erosion control measures, establishing grading limits, and demolishing existing improvements. Subsequent earthwork activities will involve site grading activities, foundation preparation, and installation of infrastructure improvements. Temporary Erosion Control The following temporary erosion and sediment control (TESC) Best Management Practices (BMPs) are offered:  Temporary construction entrances and drive lanes should be constructed with at least six inches of quarry spalls to both minimize off-site soil tracking and provide a stable access entrance surface. A woven geotextile fabric can be placed beneath the quarry spalls to provide greater stability, if needed.  Silt fencing should be placed around the site perimeter.  When not in use, soil stockpiles should be covered or otherwise protected. Stockpiles should never be placed at the top of slopes, whether the slopes are native or created through grading.  Temporary measures for controlling surface water runoff, such as interceptor trenches, sumps, or interceptor swales, should be installed prior to beginning earthwork activities.  Dry soils disturbed during construction should be wetted to reduce dust.  When appropriate, permanent planting or hydroseeding will help to stabilize site soils. DocuSign Envelope ID: 9A2B0C09-72D8-490B-A60E-EAD24B2FAACB Zarnoor Associates, LLC ES-7282 c/o Mr. Karim Karmali Page 5 May 24, 2021 Earth Solutions NW, LLC Additional TESC BMPs, as specified by the project civil engineer and/or as indicated on the TESC plans, should be incorporated into construction activities. TESC measures must be upkept and may require modification during construction to ensure proper function. Excavations and Slopes Based on the soil conditions observed at the boring locations, the following allowable temporary slope inclinations, as a function of horizontal to vertical (H:V) inclination, may be used. The applicable Federal Occupation Safety and Health Administration (OSHA) and Washington Industrial Safety and Health Act (WISHA) soil classifications are also provided:  Loose to medium dense soil 1.5H:1V (Type C)  Areas exposing groundwater seepage 1.5H:1V (Type C)  Dense to very dense, undisturbed native soil 0.75H:1V (Type A) Steeper temporary slope inclinations within undisturbed, very dense native soil may be feasible based on the soil and groundwater conditions exposed within the excavations. ESNW can evaluate the feasibility of utilizing steeper temporary slopes at the time of construction, on a case- by-case basis. In any event, an ESNW representative should observe temporary slopes to confirm inclinations are suitable for the exposed soil conditions and to provide additional excavation and slope stability recommendations, as necessary. If the recommended temporary slope inclinations cannot be achieved, temporary shoring may be necessary to support excavations. Permanent slopes should be graded to 2H:1V (or flatter) and planted with vegetation to enhance stability and minimize erosion potential. Permanent slopes should be observed by ESNW prior to vegetation and landscaping. In-situ and Imported Soil Successful use of the on-site soil as structural fill will largely be dictated by the moisture content at the time of placement and compaction. Based on the conditions observed during our subsurface exploration, the on-site soil is highly moisture sensitive. Depending on the time of year construction occurs, remedial measures (such as soil aeration) may be necessary as part of site grading and earthwork activities. If the on-site soil cannot be successfully compacted, the use of an imported soil may be necessary. In our opinion, a contingency should be provided in the project budget for export of soil that cannot be successfully compacted as structural fill, particularly if grading activities take place during periods of extended rainfall activity. In general, soils with fines contents greater than 5 percent typically degrade rapidly when exposed to periods of rainfall. DocuSign Envelope ID: 9A2B0C09-72D8-490B-A60E-EAD24B2FAACB Zarnoor Associates, LLC ES-7282 c/o Mr. Karim Karmali Page 6 May 24, 2021 Earth Solutions NW, LLC Imported structural fill soil should consist of a well-graded, granular soil that can achieve a suitable working moisture content. During wet weather conditions, imported soil intended for use as structural fill should consist of a well-graded, granular soil with a fines content of 5 percent or less (where the fines content is defined as the percent passing the Number 200 sieve, based on the minus three-quarter-inch fraction). Subgrade Preparation Foundation and slab subgrade surfaces should consist of competent, undisturbed native soil or structural fill placed and compacted atop competent native soil. ESNW should observe subgrade areas prior to placing formwork. Supplementary recommendations for subgrade improvement may be provided at the time of construction; such recommendations would likely include further mechanical compaction effort or overexcavation and replacement with suitable structural fill. Wet Season Grading Earthwork activities that occur during wet weather conditions may require additional measures to protect structural subgrades and soils intended for use as structural fill. Site-specific recommendations can be provided at the time of construction and may include leaving cut areas several inches above design elevations, covering working surfaces with crushed rock, protecting structural fill soils from adverse moisture conditions, and additional TESC recommendations. ESNW can assist in obtaining a wet season grading permit or extension, where appropriate, if required by the governing jurisdiction. Structural Fill Structural fill is defined as compacted soil placed in foundation, slab-on-grade, roadway, permanent slope, retaining wall, and utility trench backfill areas. The following recommendations are provided for soils intended for use as structural fill:  Moisture content At or slightly above optimum  Relative compaction (minimum) 95 percent (per ASTM D1557)  Loose lift thickness (maximum) 12 inches Existing site soil may only be considered suitable for use as structural fill if it can achieve a suitable moisture content at the time of placement and compaction. If the on-site soil cannot meet the above specifications, use of an imported structural fill material will likely be necessary. With respect to underground utility installations and backfill, local jurisdictions will likely dictate soil type(s) and compaction requirements. DocuSign Envelope ID: 9A2B0C09-72D8-490B-A60E-EAD24B2FAACB Zarnoor Associates, LLC ES-7282 c/o Mr. Karim Karmali Page 7 May 24, 2021 Earth Solutions NW, LLC Foundations In our opinion, the proposed mixed-use structure may be constructed on a conventional continuous and spread footing foundations bearing upon competent native soil, recompacted native soil, or new structural fill placed directly on competent native soil. Competent native soil suitable for support of the proposed building will likely be encountered beginning at depths of about two-and-one-half to five feet bgs across most of the site. Soils encountered at B-3 (northwest corner) were characterized as loose to medium dense to a depth of about 10 feet bgs. Loose native soil will likely need to be either mechanically recompacted or overexcavated and replaced with suitable structural fill to establish competent and uniform soil bearing conditions. ESNW should be on site during foundation preparation activities to further delineate areas requiring remediation and provide additional recommendations. In general, where loose or unsuitable soil conditions are exposed at foundation subgrade elevations, compaction of the soil to the specifications of structural fill or overexcavation and replacement with suitable structural fill will be necessary. Provided the foundations will be supported as suggested, the following parameters may be used for design:  Allowable soil bearing capacity 3,000 psf  Passive earth pressure 300 pcf (equivalent fluid)  Coefficient of friction 0.40 An allowable soil bearing capacity of 5,000 psf may be used for design only if foundation elements are supported directly on either dense native soil or two-inch-diameter, clean crushed rock placed directly on dense native soil. Common-earth fill is not considered suitable for use as structural fill where a higher soil bearing capacity is desired. As such, if the higher soil bearing capacity is assumed for design, overexcavation to dense native soil should be expected in some areas but will ultimately depend on final grades and subgrade elevations. The above passive pressure and friction values include a factor-of-safety (FOS) of 1.5. A one- third increase in the allowable soil bearing capacity may be assumed for short-term wind and seismic loading conditions. With structural loading as expected, total settlement in the range of one inch and differential settlement of about one-half inch is anticipated. Most settlement should occur during construction when dead loads are applied. ESNW should be retained to evaluate foundation subgrade areas at the time of construction to document suitable bearing conditions and provide additional recommendations, as deemed necessary. DocuSign Envelope ID: 9A2B0C09-72D8-490B-A60E-EAD24B2FAACB Zarnoor Associates, LLC ES-7282 c/o Mr. Karim Karmali Page 8 May 24, 2021 Earth Solutions NW, LLC Seismic Design The 2018 International Building Code (2018 IBC) recognizes the most recent edition of the Minimum Design Loads for Buildings and Other Structures manual (ASCE 7-16) for seismic design, specifically with respect to earthquake loads. Based on the soil conditions encountered at the boring locations, the parameters and values provided below are recommended for seismic design per the 2018 IBC. Parameter Value Site Class C* Mapped short period spectral response acceleration, S S (g) 1.428 Mapped 1-second period spectral response acceleration, S 1 (g) 0.488 Short period site coefficient, Fa 1.2 Long period site coefficient, Fv 1.5 Adjusted short period spectral response acceleration, S MS (g) 1.714 Adjusted 1-second period spectral response acceleration, S M1 (g) 0.732 Design short period spectral response acceleration, S DS (g) 1.142 Design 1-second period spectral response acceleration, S D1 (g) 0.488 * Assumes very dense soil conditions, encountered to a maximum depth of 26.5 feet bgs during the February 2021 field exploration, remain very dense to at least 100 feet bgs. Based on our experience with the project geologic setting (glacial till) across the Puget Sound region, soil conditions are likely consistent with this assumption. Further discussion between the project structural engineer, the project owner (or their representative), and ESNW may be prudent to determine the possible impacts to the structural design due to increased earthquake load requirements under the 2018 IBC. ESNW can provide additional consulting services to aid with design efforts, including supplementary geotechnical and geophysical investigation, upon request. Liquefaction is a phenomenon where saturated or loose soil suddenly loses internal strength and behaves as a fluid. This behavior is in response to increased pore water pressures resulting from an earthquake or another intense ground shaking. In our opinion, site susceptibility to liquefaction may be considered negligible. The absence of a shallow groundwater table and the relatively dense characteristics of the native soil were the primary bases for this opinion. DocuSign Envelope ID: 9A2B0C09-72D8-490B-A60E-EAD24B2FAACB Zarnoor Associates, LLC ES-7282 c/o Mr. Karim Karmali Page 9 May 24, 2021 Earth Solutions NW, LLC Slab-on-Grade Floors Slab-on-grade floors for the proposed mixed-use structure should be supported on competent, firm, and unyielding subgrades. Unstable or yielding subgrade areas should be recompacted or overexcavated and replaced with suitable structural fill prior to slab construction. A capillary break consisting of at least four inches of free-draining crushed rock or gravel should be placed below each slab. The free-draining material should have a fines content of 5 percent or less (where the fines content is defined as the percent passing the Number 200 sieve, based on the minus three-quarter-inch fraction). In areas where slab moisture is undesirable, installation of a vapor barrier below the slab should be considered. Vapor barriers should be made from material specifically designed for use as a vapor barrier and should be installed in accordance with the manufacturer’s recommendations. Retaining Walls Retaining walls must be designed to resist earth pressures and applicable surcharge loads. The following parameters may be used for design:  Active earth pressure (unrestrained condition) 35 pcf (equivalent fluid)  At-rest earth pressure (restrained condition) 55 pcf  Traffic surcharge* (passenger vehicles) 70 psf (rectangular distribution)  Passive earth pressure 300 pcf (equivalent fluid)  Coefficient of friction 0.40  Seismic loading condition 8H psf** * Where applicable ** Where H equals the retained height (in feet) The above passive pressure and friction values include a FOS of 1.5 and are based on a level backfill condition and level grade at the wall toe. Revised design values will be necessary if sloping grades are to be used above or below retaining walls. Additional surcharge loading from adjacent foundations, sloped backfill, or other relevant loads should be included in the retaining wall design. Retaining walls should be backfilled with free-draining material that extends along the height of the wall and a distance of at least 18 inches behind the wall. The upper 12 inches of the wall backfill may consist of a less permeable soil, if desired. A sheet drain may be considered in lieu of free-draining backfill. A perforated drainpipe should be placed along the base of the wall and connected to an approved discharge location. A typical retaining wall drainage detail is provided on Plate 3. If drainage is not provided, hydrostatic pressures should be included in the wall design. DocuSign Envelope ID: 9A2B0C09-72D8-490B-A60E-EAD24B2FAACB Zarnoor Associates, LLC ES-7282 c/o Mr. Karim Karmali Page 10 May 24, 2021 Earth Solutions NW, LLC Drainage Discrete zones of perched groundwater seepage should be anticipated in site excavations depending on the time of year grading operations take place, particularly within deeper excavations for utilities. Temporary measures to control surface water runoff and groundwater during construction would likely involve interceptor trenches, interceptor swales, and sumps. ESNW should be consulted during preliminary grading to both identify areas of seepage and provide recommendations to reduce the potential for seepage-related instability. Finish grades must be designed to direct surface drain water away from structures and slopes. Water must not be allowed to pond adjacent to structures or slopes. In our opinion, foundation drains should be installed along building perimeter footings. A typical foundation drain detail is provided on Plate 4. Preliminary Infiltration Feasibility Full infiltration is not recommended from a geotechnical standpoint given the predominance of dense silty sand encountered across most of the site. Sandier soils encountered near the northwest site corner may prove feasible for limited, targeted infiltration. However, any design would need to incorporate provisions for overflow. For feasibility and sizing considerations only, a preliminary infiltration rate of 0.5 inches per hour may be considered for infiltration facilities proposed near the northwest site corner. If infiltration is pursued, ESNW should be contacted to provide supplementary consulting and testing services. Additional services concerning infiltration feasibility would likely include in-situ testing and soil suitability verification. Utility Support and Trench Backfill In our opinion, the native soil will generally be suitable for support of utilities. Remedial measures may be necessary in some areas to provide support for utilities, such as overexcavation and replacement with structural fill and/or placement of geotextile fabric. Groundwater seepage may be encountered within utility excavations, and caving of trench walls may occur where groundwater is encountered. Depending on the time of year and conditions encountered, dewatering or temporary trench shoring may be necessary during utility excavation and installation. The on-site soil may only be suitable for use as structural backfill throughout the utility trench excavations if the soil is at (or slightly above) the optimum moisture content at the time of placement and compaction. Moisture conditioning of the soil may be necessary at some locations prior to use as structural fill. Each section of the utility lines must be adequately supported in the bedding material. Utility trench backfill should be placed and compacted to the structural fill specifications previously detailed in this report or to the applicable specifications of the presiding jurisdiction. DocuSign Envelope ID: 9A2B0C09-72D8-490B-A60E-EAD24B2FAACB Zarnoor Associates, LLC ES-7282 c/o Mr. Karim Karmali Page 11 May 24, 2021 Earth Solutions NW, LLC LIMITATIONS This study has been prepared for the exclusive use of Zarnoor Associates, LLC, and its representatives. The recommendations and conclusions provided in this study are professional opinions consistent with the level of care and skill that is typical of other members in the profession currently practicing under similar conditions in this area. No warranty, express or implied, is made. Variations in the soil and groundwater conditions observed at the boring locations may exist and may not become evident until construction. ESNW should reevaluate the conclusions provided in this study if variations are encountered. Additional Services ESNW should have an opportunity to review final project plans with respect to the geotechnical recommendations provided in this report. ESNW should also be retained to provide testing and consultation services during construction. DocuSign Envelope ID: 9A2B0C09-72D8-490B-A60E-EAD24B2FAACB Drwn.MRS Checked CGH Date Mar.2021 Date 03/29/2021 Proj.No.7282 Plate 1 Earth Solutions NWLLC Geotechnical Engineering,Construction EarthSolutionsNWLLC EarthSolutions NW LLC Observation/Testing and Environmental Services Vicinity Map Harrington Redevelopment Renton,Washington NORTHReference: King County,Washington OpenStreetMap.org NOTE:This plate may contain areas of color.ESNW cannot be responsible for any subsequent misinterpretation of the information resulting from black &white reproductions of this plate. SITE Renton DocuSign Envelope ID: 9A2B0C09-72D8-490B-A60E-EAD24B2FAACB Plate Proj.No. Date Checked By Drwn.ByEarthSolutionsNWLLCGeotechnicalEngineering,ConstructionObservation/TestingandEnvironmentalServicesEarthSolutionsNWLLCEarthSolutionsNWLLCMRS CGH 03/29/2021 7282 2BoringLocationPlan HarringtonRedevelopmentRenton,WashingtonLEGEND Approximate Location of ESNW Test Pit,Proj.No. ES-7282,Feb.2021 Subject Site Existing Building NORTH 0 2 0 4 0 8 0 Sc ale in Feet1"=4 0 ' NOTE:This plate may contain areas of color.ESNW cannot be responsible for any subsequent misinterpretation of the information resulting from black &white reproductions of this plate. NOTE:The graphics shown on this plate are not intended for design purposes or precise scale measurements,but only to illustrate the approximate test locations relative to the approximate locations of existing and /or proposed site features.The information illustrated is largely based on data provided by the client at the time of our study.ESNW cannot be responsible for subsequent design changes or interpretation of the data by others. B-1 B-1 B-2 B-3 N .E. SU N SET BOULEVARDHARRI NGTON AVENUE S.E. 340 334 340 334 DocuSign Envelope ID: 9A2B0C09-72D8-490B-A60E-EAD24B2FAACB Drwn.MRS Checked CGH Date Mar.2021 Date 03/29/2021 Proj.No.7282 Plate 3 Earth Solutions NWLLCEarthSolutionsNWLLC EarthSolutions NW LLC Geotechnical Engineer ing,C onstr uction Observation/Testing and Environmental Services Retaining Wall Drainage Detail Harrington Redevelopment Renton,Washington NOTES: Free-draining Backfill should consist of soil having less than 5 percent fines. Percent passing No.4 sieve should be 25 to 75 percent. Sheet Drain may be feasible in lieu of Free-draining Backfill,per ESNW recommendations. Drain Pipe should consist of perforated, rigid PVC Pipe surrounded with 1-inch Drain Rock. LEGEND: Free-draining Structural Backfill 1-inch Drain Rock 18"Min. Structural Fill Perforated Rigid Drain Pipe (Surround in Drain Rock) SCHEMATIC ONLY -NOT TO SCALE NOT A CONSTRUCTION DRAWING DocuSign Envelope ID: 9A2B0C09-72D8-490B-A60E-EAD24B2FAACB Drwn.MRS Checked CGH Date Mar.2021 Date 03/29/2021 Proj.No.7282 Plate 4 Earth Solutions NWLLC Geotechnical Engineering,Construction Observation/Testing and Environmental Services EarthSolutionsNWLLC EarthSolutions NW LLC Footing Drain Detail Harrington Redevelopment Renton,Washington Slope Perforated Rigid Drain Pipe (Surround in Drain Rock) 18"Min. NOTES: Do NOT tie roof downspouts to Footing Drain. Surface Seal to consist of 12"of less permeable,suitable soil.Slope away from building. LEGEND: Surface Seal:native soil or other low-permeability material. 1-inch Drain Rock SCHEMATIC ONLY -NOT TO SCALE NOT A CONSTRUCTION DRAW ING DocuSign Envelope ID: 9A2B0C09-72D8-490B-A60E-EAD24B2FAACB Earth Solutions NW, LLC Appendix A Subsurface Exploration Boring Logs ES-7282 Subsurface conditions at the subject site were explored on February 12, 2021, by advancing three borings using a drill rig and operators retained by our firm. The approximate locations of the borings are illustrated on Plate 2 of this study. The boring logs are provided in this Appendix. The borings were advanced to a maximum depth of approximately 26.5 feet bgs. The final logs represent the interpretations of the field logs and the results of laboratory analyses. The stratification lines on the logs represent the approximate boundaries between soil types. In actuality, the transitions may be more gradual. DocuSign Envelope ID: 9A2B0C09-72D8-490B-A60E-EAD24B2FAACB GRAVEL AND GRAVELLY SOILS CLAYEY GRAVELS, GRAVEL - SAND - CLAY MIXTURES WELL-GRADED SANDS, GRAVELLY SANDS, LITTLE OR NO FINES POORLY-GRADED SANDS, GRAVELLY SAND, LITTLE OR NO FINES SILTY SANDS, SAND - SILT MIXTURES CLAYEY SANDS, SAND - CLAY MIXTURES INORGANIC SILTS AND VERY FINE SANDS, ROCK FLOUR, SILTY OR CLAYEY FINE SANDS OR CLAYEY SILTS WITH SLIGHT PLASTICITY INORGANIC CLAYS OF LOW TO MEDIUM PLASTICITY, GRAVELLY CLAYS, SANDY CLAYS, SILTY CLAYS, LEAN CLAYS ORGANIC SILTS AND ORGANIC SILTY CLAYS OF LOW PLASTICITY INORGANIC SILTS, MICACEOUS OR DIATOMACEOUS FINE SAND OR SILTY SOILS INORGANIC CLAYS OF HIGH PLASTICITY SILTS AND CLAYS MORE THAN 50% OF MATERIAL IS LARGER THAN NO. 200 SIEVE SIZE MORE THAN 50% OF MATERIAL IS SMALLER THAN NO. 200 SIEVE SIZE MORE THAN 50% OF COARSE FRACTION PASSING ON NO. 4 SIEVE MORE THAN 50% OF COARSE FRACTION RETAINED ON NO. 4 SIEVE SOIL CLASSIFICATION CHART (APPRECIABLE AMOUNT OF FINES) (APPRECIABLE AMOUNT OF FINES) (LITTLE OR NO FINES) FINE GRAINED SOILS SAND AND SANDY SOILS SILTS AND CLAYS ORGANIC CLAYS OF MEDIUM TO HIGH PLASTICITY, ORGANIC SILTS PEAT, HUMUS, SWAMP SOILS WITH HIGH ORGANIC CONTENTS LETTERGRAPH SYMBOLSMAJOR DIVISIONS COARSE GRAINED SOILS TYPICAL DESCRIPTIONS WELL-GRADED GRAVELS, GRAVEL - SAND MIXTURES, LITTLE OR NO FINES POORLY-GRADED GRAVELS, GRAVEL - SAND MIXTURES, LITTLE OR NO FINES SILTY GRAVELS, GRAVEL - SAND - SILT MIXTURES CLEAN GRAVELS GRAVELS WITH FINES CLEAN SANDS (LITTLE OR NO FINES) SANDS WITH FINES LIQUID LIMIT LESS THAN 50 LIQUID LIMIT GREATER THAN 50 HIGHLY ORGANIC SOILS DUAL SYMBOLS are used to indicate borderline soil classifications. The discussion in the text of this report is necessary for a proper understanding of the nature of the material presented in the attached logs. GW GP GM GC SW SP SM SC ML CL OL MH CH OH PT Earth Solutions NW LLC DocuSign Envelope ID: 9A2B0C09-72D8-490B-A60E-EAD24B2FAACB 316.0 SS SS SS SS SS 67 67 67 100 0 22-24-31 (55) 17-28-28 (56) 14-15-20 (35) 19-26-28 (54) 50/5" MC = 9.3% Fines = 23.9% MC = 6.5% MC = 13.2% MC = 5.3% MC = 8.4% SM 20.0 Brown silty SAND, medium dense, moist -becomes gray, very dense [USDA Classification: slightly gravelly SAND] -becomes dense -minor perched groundwater seepage -increased sand content -becomes very dense NOTES Surface Conditions: asphalt ~1.5" to 2" GROUND ELEVATION 336 ft LOGGED BY CGH DRILLING METHOD HSA HOLE SIZE DRILLING CONTRACTOR Geologic Drill Partners GROUND WATER LEVELS: CHECKED BY KDH DATE STARTED 2/12/21 COMPLETED 2/12/21 AT TIME OF DRILLING --- AT END OF DRILLING --- AFTER DRILLING --- (Continued Next Page)SAMPLE TYPENUMBERDEPTH(ft)0 5 10 15 20 PAGE 1 OF 2 BORING NUMBER B-1 PROJECT NUMBER ES-7282 PROJECT NAME Harrington Redevelopment GENERAL BH / TP / WELL - 7282.GPJ - GINT STD US.GDT - 5/24/21Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711 RECOVERY %BLOWCOUNTS(N VALUE)TESTS U.S.C.S.MATERIAL DESCRIPTION GRAPHICLOGDocuSign Envelope ID: 9A2B0C09-72D8-490B-A60E-EAD24B2FAACB 315.5SS10050/6"MC = 9.0%SM 20.5 Gray silty SAND, very dense, moist Boring terminated at 20.5 feet below existing grade. Groundwater seepage encountered at 10.0 feet during drilling. Boring backfilled with bentonite.SAMPLE TYPENUMBERDEPTH(ft)20 PAGE 2 OF 2 BORING NUMBER B-1 PROJECT NUMBER ES-7282 PROJECT NAME Harrington Redevelopment GENERAL BH / TP / WELL - 7282.GPJ - GINT STD US.GDT - 5/24/21Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711 RECOVERY %BLOWCOUNTS(N VALUE)TESTS U.S.C.S.MATERIAL DESCRIPTION GRAPHICLOGDocuSign Envelope ID: 9A2B0C09-72D8-490B-A60E-EAD24B2FAACB 331.5 316.0 SS SS SS SS SS 100 100 100 100 50 1-1-1 (2) 4-14-19 (33) 50/5" 11-14-18 (32) 50/4" MC = 14.2% MC = 13.9% Fines = 26.6% MC = 8.7% MC = 11.0% MC = 10.7% SM SM 4.5 20.0 Brown silty SAND, very loose, moist (Fill) -trace organic material Brown silty SAND, loose, moist [USDA Classification: slightly gravelly sandy LOAM] -becomes gray, dense -minor iron oxide staining -becomes very dense -becomes dense -possible obstruction -no recovery due to obstruction. Sample taken from spoils. NOTES Surface Conditions: asphalt ~1" GROUND ELEVATION 336 ft LOGGED BY CGH DRILLING METHOD HSA HOLE SIZE DRILLING CONTRACTOR Geologic Drill Partners GROUND WATER LEVELS: CHECKED BY KDH DATE STARTED 2/12/21 COMPLETED 2/12/21 AT TIME OF DRILLING --- AT END OF DRILLING --- AFTER DRILLING --- (Continued Next Page)SAMPLE TYPENUMBERDEPTH(ft)0 5 10 15 20 PAGE 1 OF 2 BORING NUMBER B-2 PROJECT NUMBER ES-7282 PROJECT NAME Harrington Redevelopment GENERAL BH / TP / WELL - 7282.GPJ - GINT STD US.GDT - 5/24/21Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711 RECOVERY %BLOWCOUNTS(N VALUE)TESTS U.S.C.S.MATERIAL DESCRIPTION GRAPHICLOGDocuSign Envelope ID: 9A2B0C09-72D8-490B-A60E-EAD24B2FAACB SS 50/0"Boring terminated at 20.0 feet below existing grade. No groundwater encountered during drilling. Boring backfilled with bentonite.SAMPLE TYPENUMBERDEPTH(ft)PAGE 2 OF 2 BORING NUMBER B-2 PROJECT NUMBER ES-7282 PROJECT NAME Harrington Redevelopment GENERAL BH / TP / WELL - 7282.GPJ - GINT STD US.GDT - 5/24/21Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711 RECOVERY %BLOWCOUNTS(N VALUE)TESTS U.S.C.S.MATERIAL DESCRIPTION GRAPHICLOGDocuSign Envelope ID: 9A2B0C09-72D8-490B-A60E-EAD24B2FAACB 330.5 318.0 SS SS SS SS SS 67 67 67 100 55 5-5-6 (11) 4-4-6 (10) 5-3-2 (5) 2-3-13 (16) 13-50/5" MC = 8.4% MC = 6.8% Fines = 9.5% MC = 9.6% MC = 11.0% Fines = 29.9% MC = 7.5% SP- SM SM 7.5 20.0 Brown poorly graded SAND with silt and gravel, medium dense, moist [USDA Classification: very gravelly loamy coarse SAND] Brown silty SAND, loose, moist [USDA Classification: gravelly fine sandy LOAM] -becomes gray, medium dense -becomes very dense NOTES Surface Conditions: asphalt ~1" GROUND ELEVATION 338 ft LOGGED BY CGH DRILLING METHOD HSA HOLE SIZE DRILLING CONTRACTOR Geologic Drill Partners GROUND WATER LEVELS: CHECKED BY KDH DATE STARTED 2/12/21 COMPLETED 2/12/21 AT TIME OF DRILLING --- AT END OF DRILLING --- AFTER DRILLING --- (Continued Next Page)SAMPLE TYPENUMBERDEPTH(ft)0 5 10 15 20 PAGE 1 OF 2 BORING NUMBER B-3 PROJECT NUMBER ES-7282 PROJECT NAME Harrington Redevelopment GENERAL BH / TP / WELL - 7282.GPJ - GINT STD US.GDT - 5/24/21Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711 RECOVERY %BLOWCOUNTS(N VALUE)TESTS U.S.C.S.MATERIAL DESCRIPTION GRAPHICLOGDocuSign Envelope ID: 9A2B0C09-72D8-490B-A60E-EAD24B2FAACB 317.0 311.5 SS SS 100 100 25-30-38 (68) 26-26-42 (68) MC = 7.4% Fines = 10.3% MC = 5.0% SM SW- SM 21.0 26.5 Gray silty SAND, very dense, moist [USDA Classification: slightly gravelly coarse SAND] Gray well-graded SAND with silt, very dense, moist -4" silty sand lens Boring terminated at 26.5 feet below existing grade. No groundwater encountered during drilling. Boring backfilled with bentonite.SAMPLE TYPENUMBERDEPTH(ft)20 25 PAGE 2 OF 2 BORING NUMBER B-3 PROJECT NUMBER ES-7282 PROJECT NAME Harrington Redevelopment GENERAL BH / TP / WELL - 7282.GPJ - GINT STD US.GDT - 5/24/21Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711 RECOVERY %BLOWCOUNTS(N VALUE)TESTS U.S.C.S.MATERIAL DESCRIPTION GRAPHICLOGDocuSign Envelope ID: 9A2B0C09-72D8-490B-A60E-EAD24B2FAACB Earth Solutions NW, LLC Appendix B Laboratory Test Results ES-7282 DocuSign Envelope ID: 9A2B0C09-72D8-490B-A60E-EAD24B2FAACB 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 0.0010.010.1110100 3 D100 140 Specimen Identification 1 fine 6 HYDROMETER 304 23.9 26.6 9.5 29.9 10.3 101/2 COBBLES Specimen Identification 4 coarse 20 401.5 8 14 USDA: Gray Slightly Gravelly Loamy Sand. USCS: SM. USDA: Gray Slightly Gravelly Sandy Loam. USCS: SM. USDA: Brown Very Gravelly Loamy Coarse Sand. USCS: SP-SM with Gravel. USDA: Gray Gravelly Fine Sandy Loam. USCS: SM. USDA: Gray Slightly Gravelly Coarse Sand. USCS: SW-SM. 6 60 PERCENT FINER BY WEIGHTD10 0.115 0.096 0.345 0.075 0.232 0.376 0.371 2.788 0.214 0.599 GRAIN SIZE DISTRIBUTION 100 35.00 8.22 LL B-01 B-02 B-03 B-03 B-03 0.08 3/4 U.S. SIEVE OPENING IN INCHES U.S. SIEVE NUMBERS GRAVEL SAND 19 19 37.5 37.5 9.5 %Silt 0.54 1.24 B-01 B-02 B-03 B-03 B-03 2 2003 Cc CuClassification %Clay 16 PID60 D30 coarse SILT OR CLAYfinemedium GRAIN SIZE IN MILLIMETERS 3/8 50 2.5ft. 5.0ft. 5.0ft. 10.0ft. 20.0ft. 2.50ft. 5.00ft. 5.00ft. 10.00ft. 20.00ft. PL PROJECT NUMBER ES-7282 PROJECT NAME Harrington Redevelopment GRAIN SIZE USDA ES-7282 HARRINGTON REDEVELOPMENT.GPJ GINT US LAB.GDT 2/24/21Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711 DocuSign Envelope ID: 9A2B0C09-72D8-490B-A60E-EAD24B2FAACB Earth Solutions NW, LLC Report Distribution ES-7282 EMAIL ONLY Zarnoor Associates, LLC c/o Mr. Karim Karmali 19515 North Creek Parkway, Suite 314 Bothell, Washington 98011 Attention: Mr. Nazim Karmali EMAIL ONLY Grouparchitect 1735 Westlake Avenue North, Suite 200 Seattle, Washington 98109 Attention: Mr. Kyle Stevens DocuSign Envelope ID: 9A2B0C09-72D8-490B-A60E-EAD24B2FAACB