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Home My WebLink AboutEx_09_Geotech_ReportEarthSolutionsNWLLC 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 PROPOSED SHORT PLAT 6304 SOUTHEAST 2 PLACE RENTON,WASHINGTON ES-8178 ND Exhibit 9 DocuSign Envelope ID: 121137F3-D672-460F-8802-55F5D3EB78FE PREPARED FOR SAA VENTURES, LLC November 2, 2021 _________________________ Chase G. Halsen, L.G. Project Geologist _________________________ Scott S. Riegel, L.G., L.E.G. Senior Project Manager GEOTECHNICAL ENGINEERING STUDY PROPOSED SHORT PLAT 6304 SOUTHEAST 2ND PLACE RENTON, WASHINGTON ES-8178 Earth Solutions NW, LLC 15365 Northeast 90th Street, Suite 100 Redmond, Washington 98052 Phone: 425-449-4704 | Fax: 425-449-4711 www.earthsolutionsnw.com 11/02/2021 DocuSign Envelope ID: 121137F3-D672-460F-8802-55F5D3EB78FE 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: 121137F3-D672-460F-8802-55F5D3EB78FE 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: 121137F3-D672-460F-8802-55F5D3EB78FE November 2, 2021 ES-8178 SAA Ventures, LLC 6463 – 167th Lane Southeast Bellevue, Washington 98006 Attention: Mr. Ravikumar Mandaleeka Mr. Kiran Komaravolu Greetings, Gentlemen: Earth Solutions NW, LLC (ESNW) is pleased to present this geotechnical engineering report in support of the proposed development. We understand the project is pursuing construction of a residential short plat and associated infrastructure improvements. From a geotechnical standpoint, development as currently proposed is feasible. Based on the conditions encountered during our subsurface exploration, the site is underlain by glacial till deposits. In our opinion, the proposed residential structures can be constructed on conventional continuous and spread foundations bearing on competent native soil, recompacted native soil, or new structural fill placed directly on competent native soils. Native soils considered capable for support of the proposed residences are anticipated to be first encountered at depths of about two to four-and-one-half feet below existing grades. Where loose or otherwise unsuitable soil conditions are encountered at foundation subgrades, additional compaction efforts or overexcavation and restoration with structural fill will likely be necessary. From a geotechnical standpoint, full infiltration is considered infeasible for the project given the widespread presence of unweathered glacial till across the site. Low-impact development designs or limited infiltration elements, such as permeable pavement and bio-filtration, is considered feasible provided that it is targeted to the weathered soil horizon encountered within the upper few feet of existing grades. A further discussion of infiltration feasibility and design considerations are provided within this report. 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: 121137F3-D672-460F-8802-55F5D3EB78FE Earth Solutions NW, LLC Table of Contents ES-8178 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 Structural Fill ................................................................ 6 Subgrade Preparation .................................................. 6 Wet Season Grading .................................................... 6 Foundations ............................................................................ 7 Seismic Design ....................................................................... 8 Slab-on-Grade Floors ............................................................. 8 Retaining Walls ....................................................................... 9 Drainage................................................................................... 10 Infiltration Evaluation ................................................... 10 Preliminary Pavement Sections ............................................. 11 Utility Support and Trench Backfill ....................................... 12 LIMITATIONS ...................................................................................... 12 Additional Services ................................................................. 12 DocuSign Envelope ID: 121137F3-D672-460F-8802-55F5D3EB78FE Earth Solutions NW, LLC Table of Contents Cont’d ES-8178 GRAPHICS Vicinity Map Test Pit Location Plan Retaining Wall Drainage Detail Plate 1 Plate 2 Plate 3 Plate 4 Footing Drain Detail APPENDICES Appendix A Subsurface Exploration Test Pit Logs Appendix B Laboratory Test Results DocuSign Envelope ID: 121137F3-D672-460F-8802-55F5D3EB78FE Earth Solutions NW, LLC GEOTECHNICAL ENGINEERING STUDY PROPOSED SHORT PLAT 6304 SOUTHEAST 2ND PLACE RENTON, WASHINGTON ES-8178 INTRODUCTION General This geotechnical engineering study was prepared for the proposed residential short plat to be constructed at 6304 Southeast 2nd Place, in Renton, Washington. The purpose of this study was to provide geotechnical recommendations for the proposed development and included the following geotechnical services:  Test pits to characterize site soil and groundwater conditions.  Laboratory testing of representative soil samples collected at the test pit locations.  Engineering analyses.  Preparation of this geotechnical engineering study. The following documents and resources were reviewed as part of our report preparation:  Geologic Map of the Renton Quadrangle, Washington, prepared by D.R. Mullineaux, 1965.  Online Web Soil Survey (WSS) resource, maintained by the Natural Resources Conservation Service under the United States Department of Agriculture (USDA).  Surface Water Design Manual, prepared by the City of Renton, Washington, dated December 12, 2016.  GIS mapping application, maintained by the City of Renton, Washington.  Title IV of the Renton Municipal Code. DocuSign Envelope ID: 121137F3-D672-460F-8802-55F5D3EB78FE SAA Ventures, LLC ES-8178 November 2, 2021 Page 2 Earth Solutions NW, LLC Project Description We understand the project is pursing construction of a four-lot short plat. The existing residence will remain and the parcel will be subdivided to create three new home building sites. At the time of report submission, specific building load plans were not available for review. Based on our experience with similar developments, the proposed residential structures will likely be two to three stories each and constructed using relatively lightly loaded wood framing supported on conventional foundations. Perimeter footing loads will likely be about 2 to 3 kips per lineal foot. Slab-on-grade loading is anticipated to be approximately 150 pounds per square foot (psf). We anticipate a combination of grade modifications (cuts or fills) of about five feet will likely be required to establish design building pad elevations. The feasibility of infiltration is being investigated as part of the project stormwater management plans. 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 along the north side of Southeast 2 nd Place, about 130 feet west of the intersection with 156th Avenue Southeast, in Renton, Washington. The approximate site location is depicted on Plate 1 (Vicinity Map). The site area consists of King County parcel number 142305-9033 and totals about 0.99 acre. Topography descends to the southwest with about 18 feet of elevation change occur across the site. Surface vegetation consists primarily of hard and soft landscaping features. The site is currently developed with a single-family residence and is bordered to the north, east, and west by single-family residences and to the south by Southeast 2nd Place. Subsurface An ESNW representative observed, logged, and sampled the excavation of five test pits on September 27, 2021. The test pit exploration was performed using a mini-trackhoe and operator retained by our firm. The approximate locations of the test pits are depicted on Plate 2 (Test Pit Location Plan). Representative soil samples collected at the test pit locations were analyzed in general accordance with Unified Soil Classification System (USCS) and USDA methods and procedures. The following sections provide a generalized characterization of the encountered subsurface conditions. Please refer to the test pit logs provided in Appendix A for a more detailed description of subsurface conditions. DocuSign Envelope ID: 121137F3-D672-460F-8802-55F5D3EB78FE SAA Ventures, LLC ES-8178 November 2, 2021 Page 3 Earth Solutions NW, LLC Topsoil and Fill Topsoil was encountered in the upper approximate 4 to 12 inches of existing grades at the test pit locations. The topsoil was characterized by a dark brown color, trace organic matter, and root inclusions. Fill was encountered at TP-4 and TP-5 during our subsurface exploration. The fill was characterized as dark brown silty sand in a loose and moist condition, extending to a depth between about one to two-and-one-half feet below the ground surface (bgs). Trace debris was also observed within the fill. The relic topsoil horizon was observed underlying the fill and was approximately six inches thick. Native Soil Underlying topsoil and localized fill, native soils were characterized primarily as silty sand with or without gravel (USCS: SM). The upper approximate four to four-and-one-half feet was characterized as the weathered horizon due to the observed brown hue and loose to medium dense in-situ condition. Thereafter, native soils transitioned into an unweathered condition and were observed in a dense to very dense state, extending to a maximum exploration depth of about nine feet bgs. Localized areas of increased sands and gravel contents were locally observed; however, silty sand is considered the predominate native soil type. Geologic Setting The referenced geologic map identifies ground moraine deposits (Qgt), otherwise known as glacial till, as underlying the site and surrounding areas. Ground moraine deposits (commonly termed hardpan) are characterized as an unsorted mixture of sand, silt, clay, and gravel. The referenced WSS resource identifies Alderwood gravelly sandy loam (Map Unit Symbol: AgC) as underlying the site and surrounding areas. These soils are associated with ridge and hill landforms and formed in glacial drift. Based on our field exploration, encountered native soils correlate with local geologic mapping designations of glacial till. Groundwater Perched groundwater was encountered at three test pit locations, generally at an exposure depth between about four-and-three-quarters to eight feet bgs. The seepage was characterized as being minor to heavy with respect to flow volume. We do not characterize the seepage to reflect the local, shallow groundwater table. Groundwater seepage rates and elevations fluctuate depending on many factors, including precipitation duration and intensity, the time of year, and soil conditions. In general, groundwater elevations and flow rates are higher during the winter, spring, and early summer months. DocuSign Envelope ID: 121137F3-D672-460F-8802-55F5D3EB78FE SAA Ventures, LLC ES-8178 November 2, 2021 Page 4 Earth Solutions NW, LLC Critical Areas Review We reviewed the City of Renton (COR) GIS map database to assist our field observations in identifying the presence of jurisdictionally recognized geological hazard areas both on site and directly adjacent to the site. We understand that the COR recognizes steep slope, landslide, erosion, seismic, and coal mine hazards as geological hazard areas. Based on our review of the COR GIS database, Renton Municipal Code (RMC), Title IV, Chapter 3, and our field observations, it is our opinion that none of the above geologic hazards are present on site or within the immediate vicinity of the site. Therefore, standard development practices and BMPs may be applied to this project. DISCUSSION AND RECOMMENDATIONS General Based on the results of our investigation, construction of the proposed residential short plat is feasible from a geotechnical standpoint. The primary geotechnical considerations for the proposal are in reference to structural fill placement and compaction, foundation design, and stormwater management. Site Preparation and Earthwork Initial site preparation activities will consist of installing temporary erosion control measures, establishing grading limits, and site clearing. Subsequent earthwork activities will involve mass excavation, foundation subgrade preparation activities, and related infrastructure improvements. Temporary Erosion Control The following temporary erosion and sediment control (TESC) Best Management Practices (BMPs) should be considered:  Silt fencing should be placed around the site perimeter, where appropriate.  Temporary construction entrances and drive lanes should be constructed with at least six inches of quarry spalls to minimize off-site soil tracking and provide a stable access entrance surface. A woven geotextile fabric may be placed underneath the quarry spalls to provide greater stability, if needed.  When not in use, soil stockpiles should be covered or otherwise protected. Soil stockpiles should never be placed near the top of a slope.  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 minimize dust. DocuSign Envelope ID: 121137F3-D672-460F-8802-55F5D3EB78FE SAA Ventures, LLC ES-8178 November 2, 2021 Page 5 Earth Solutions NW, LLC Additional TESC BMPs, as specified by the project design team and indicated on the plans, should be incorporated into construction activities. TESC measures must be actively monitored and modified during construction as site conditions require, as approved by the site erosion control lead to ensure proper performance is maintained. Excavations and Slopes Based on the soil conditions observed at the test 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 1.5H:1V (Type C)  Dense to very dense 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. If pursued, ESNW can evaluate the feasibility of utilizing steeper temporary slopes on a case-by-case basis at the time of construction. In any case, 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 vegetating and landscaping. In-situ and Imported Soil Based on the conditions observed during our subsurface exploration, site soils will exhibit a high sensitivity to moisture and are not suitable for use as structural fill unless the moisture content is at or slightly above optimum (determined using modified Proctor ASTM D-1557) prior to placement and compaction. Successful use of on-site soil as structural fill will largely be dictated by the moisture content at the time of placement and compaction. 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: 121137F3-D672-460F-8802-55F5D3EB78FE SAA Ventures, LLC ES-8178 November 2, 2021 Page 6 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). Structural Fill Structural fill is defined as compacted soil placed in 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 (Modified Proctor)  Loose lift thickness (maximum) 12 inches The on-site soil may not be suitable for use as structural fill unless a suitable moisture content is achieved at the time of placement and compaction. If the on-site soil cannot achieve 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. Subgrade Preparation Foundation and slab subgrade surfaces should consist of competent, undisturbed native soil or structural fill placed and compacted directly on a competent native soil subgrade. 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. Overexcavation of existing fill in the area of TP-4 and TP-5 should be anticipated prior to mass grading activities. However, the extent of overexcavation should be evaluated by ESNW at the time of construction. 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 also assist in obtaining a wet season grading permit or extension, where appropriate, if required by the presiding jurisdiction. DocuSign Envelope ID: 121137F3-D672-460F-8802-55F5D3EB78FE SAA Ventures, LLC ES-8178 November 2, 2021 Page 7 Earth Solutions NW, LLC Foundations Based on the conditions encountered during our fieldwork, in our opinion, the proposed residences can be constructed on conventional continuous and spread foundations bearing on competent native soil, recompacted native soil, or new structural fill placed directly on competent native soils. Native soils considered capable for support of the proposed residences are anticipated to be first encountered at depths of about two to four-and-one-half feet bgs. Where loose or otherwise unsuitable soil conditions are encountered at foundation subgrades, additional compaction efforts or overexcavation and restoration with structural fill will likely be necessary. Provided the foundations will be supported as recommended, the following parameters may be used for foundation design:  Allowable soil bearing capacity 2,500 psf  Passive earth pressure* 300 pcf (equivalent fluid)  Coefficient of friction 0.40 * Assumes sides of the foundation will be backfilled with compacted structural fill. ESNW must be contacted to review foundation plans and design subgrade elevations to confirm the presence of suitable soil conditions for support of the proposed foundation loads. Preliminary review of the foundation plans will also provide an opportunity for ESNW to identify areas that may require overexcavation and restoration prior to construction. A one-third increase in the allowable soil bearing capacity may be assumed for short-term wind and seismic loading conditions. The above passive pressure and friction values include a factor- of-safety of 1.5. 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. DocuSign Envelope ID: 121137F3-D672-460F-8802-55F5D3EB78FE SAA Ventures, LLC ES-8178 November 2, 2021 Page 8 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) 1.371 Mapped 1-second period spectral response acceleration, S 1 (g) 0.469 Short period site coefficient, Fa 1.2 Long period site coefficient, Fv 1.5 Adjusted short period spectral response acceleration, S MS (g) 1.645 Adjusted 1-second period spectral response acceleration, S M1 (g) 0.703 Design short period spectral response acceleration, S DS (g) 1.097 Design 1-second period spectral response acceleration, S D1 (g) 0.469 * Assumes very dense soil conditions, encountered to a maximum depth of nine feet bgs during the September 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. Slab-on-Grade Floors Slab-on-grade floors for the proposed structure should be supported on competent, well- compacted, firm, and unyielding subgrades. Unstable or yielding subgrade areas should be recompacted or overexcavated and replaced with suitable structural fill prior to slab construction. DocuSign Envelope ID: 121137F3-D672-460F-8802-55F5D3EB78FE SAA Ventures, LLC ES-8178 November 2, 2021 Page 9 Earth Solutions NW, LLC 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. The vapor barrier should be a material specifically designed for use as a vapor barrier and should be installed in accordance with the specifications of the manufacturer. 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)  Allowable soil bearing capacity 2,500 psf  Coefficient of friction 0.40  Seismic surcharge 8H psf** * Where applicable. ** Where H equals the retained height (in feet). Additional surcharge loading from foundations, sloped backfill, or other loading should be included in the retaining wall design, as appropriate. Drainage should be provided behind retaining walls such that hydrostatic pressures do not develop. If drainage is not provided, hydrostatic pressures should be included in the wall design, as appropriate. ESNW should review retaining wall designs to verify that appropriate earth pressure values have been incorporated into the design and to provide additional recommendations, as necessary. Retaining walls should be backfilled with free-draining material that extends along the height of the wall and a distance of at least 12 inches behind the wall. The upper one foot of the wall backfill may consist of a less permeable (surface seal) soil, if desired. In lieu of free-draining backfill, use of an approved sheet drain material may also be considered, based on the observed subsurface and groundwater conditions. ESNW should review conditions at the time of construction and provide recommendations for sheet drain material, as appropriate. A perforated drainpipe should be placed along the base of the wall and connected to an appropriate discharge location. A typical retaining wall drainage detail is illustrated on Plate 3. DocuSign Envelope ID: 121137F3-D672-460F-8802-55F5D3EB78FE SAA Ventures, LLC ES-8178 November 2, 2021 Page 10 Earth Solutions NW, LLC Drainage Surface grades must be designed to direct water away from the buildings to the extent practical. The grade adjacent to the buildings should be sloped away at a gradient of at least 2 percent for a horizontal distance of at least 10 feet (or as building and property setbacks allow). In no instance should water be allowed to collect, pond, or flow uncontrolled above and over sloping areas. Groundwater seepage zones may be encountered during construction, depending on the time of year grading operations take place. Temporary measures to control surface water runoff and groundwater seepage during construction would likely involve interceptor trenches and sumps. ESNW should be consulted during preliminary grading and excavation activities to identify areas of seepage and to provide recommendations to reduce the potential for seepage-related instability. In our opinion, foundation drains should be installed along building perimeter footings. A typical foundation drain detail is provided on Plate 4. Infiltration Evaluation To assist in determining infiltration feasibility for the project, ESNW conducted two, small-scale Pilot Infiltration Tests (PITs) during the September 2021 subsurface exploration. The following table depicts each infiltration test location, test date, test depth, measured rate, appropriate safety factors, and recommended design rate. Location Soil Type Test Depth (ft. bgs) Measured Rate (in/hr.) Reduction Factors Recommended Design Rate (in/hr.) Ft Fg Fp TP-2 GM 2’ 5.5 0.5 1* 0.7 1.9 TP-3 SM 6’ 0.24 0.5 1* 0.7 N/A * Correction factor of facility geometry is assumed at 1. This value may need to be updated upon final facility design. From a geotechnical standpoint, low-impact-development (LID) designs, such as permeable pavement, that are targeted to the upper weathered soil horizon is feasible for the proposed project and native soil conditions. Based on our representative in-situ testing, a long-term design rate of 1.9 in/hr. is considered appropriate for infiltration facilities that target the weathered soil horizon, which was generally encountered in the upper approximate three-and-one-half to four feet of existing grades. Given the consistent nature of the weathered horizon, the above rate should be considered suitable for site infiltration facilities targeted to this section of the deposit. Infiltration of any type into the unweathered till deposit in considered infeasible from a geotechnical standpoint given the very low measured field rate, appreciable fines contents, and dense to very dense in-situ condition. DocuSign Envelope ID: 121137F3-D672-460F-8802-55F5D3EB78FE SAA Ventures, LLC ES-8178 November 2, 2021 Page 11 Earth Solutions NW, LLC Infiltration into the weathered zone should be situated as high within the native soil as possible, to provide maximum capacity for infiltration. Areas targeted for infiltration will require protection from traffic, compaction, or other activities that may impede or otherwise degrade the infiltration capacity. Site runoff and other processes that could lead to sediment accumulation must not be allowed within areas targeted for infiltration, as this could also degrade the infiltration capacity of the native soils. Any area that will have a shallow infiltration facility must be identified and protected prior to, and throughout, mass earthwork operations. Failure to do so may reduce the infiltration characteristics of the near surface soils. It may be prudent to consider implementing an overflow provision into the LID designs if practical. ESNW should review the final grading and storm plans to confirm the recommendations in this evaluation are incorporated. ESNW should also observe the subgrade for infiltration devices prior to construction to confirm soil conditions are as anticipated. Preliminary Pavement Sections The performance of site pavements is largely related to the condition of the underlying subgrade. To ensure adequate pavement performance, the subgrade should be in a firm and unyielding condition when subjected to proofrolling with a loaded dump truck. Structural fill in pavement areas should be compacted to the specifications previously detailed in this report. Soft, wet, or otherwise unsuitable subgrade areas may still exist after base grading activities. Areas containing unsuitable or yielding subgrade conditions will require remedial measures, such as overexcavation and replacement with crushed rock or structural fill, prior to pavement. If roadway areas will be designed with an inverted crown, additional drainage measures may be recommended at the time of construction to help maintain subgrade stability and pavement performance. For lightly loaded pavement areas subjected primarily to passenger vehicles, the following preliminary pavement sections may be considered:  A minimum of two inches of hot-mix asphalt (HMA) placed over four inches of crushed rock base (CRB).  A minimum of two inches of HMA placed over three inches of asphalt-treated base (ATB). The HMA, ATB, and CRB materials should conform to the specifications of the governing jurisdiction. All soil base material should be compacted to at least 95 percent of the maximum dry density. Final pavement design recommendations can be provided once final traffic loading has been determined. City of Renton standards may supersede the recommendations provided in this report. DocuSign Envelope ID: 121137F3-D672-460F-8802-55F5D3EB78FE SAA Ventures, LLC ES-8178 November 2, 2021 Page 12 Earth Solutions NW, LLC Utility Support and Trench Backfill In our opinion, native soils will generally be competent for support of utilities. In general, native soils may be suitable for use as structural backfill throughout utility trench excavations, provided the soils are at (or slightly above) the optimum moisture content at the time of placement and compaction. Structural trench backfill should not be placed dry of the optimum moisture content. Each section of the site utility lines must be adequately supported in appropriate bedding material. Utility trench backfill should be placed and compacted to the specifications of structural fill (as previously detailed in this report) or to the applicable specifications of the presiding jurisdiction. LIMITATIONS This study has been prepared for the exclusive use of SAA Ventures, LLC and its representatives. No warranty, express or implied, is made. The recommendations and conclusions provided in this geotechnical engineering 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. Variations in the soil and groundwater conditions observed at the test pit locations may exist and may not become evident until construction. ESNW should reevaluate the conclusions provided in this geotechnical engineering study if variations are encountered. Additional Services ESNW should have an opportunity to review the final design 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: 121137F3-D672-460F-8802-55F5D3EB78FE Drwn.MRS Checked CGH Date Nov.2021 Date 11/01/2021 Proj.No.8178 Plate 1 Earth Solutions NWLLC Geotechnical Engineering,Construction EarthSolutionsNWLLC EarthSolutions NW LLC Observation/Testing and Environmental Ser vices Vicinity Map 2nd Place Short Plat Renton,Washington 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. NORTHReference: King County,Washington OpenStreetMap.org SITE Renton DocuSign Envelope ID: 121137F3-D672-460F-8802-55F5D3EB78FE Drwn. MRS Checked CGH Date Nov. 2021 Date 11/01/2021 Proj. No. 8178 Plate 2 Earth Solutions NWLLC Geotechnical Engineering,Construction EarthSolutionsNWLLC EarthSolutions NW LLC Observation/Testing and Environmental Services Test Pit Location Plan 2nd Place Short Plat Renton, WashingtonNOTE: 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. NORTHLEGEND Approximate Location of ESNW Test Pit, Proj. No. ES-8178, Sept. 2021 Subject Site Existing Building 0 40 80 160 Scale in Feet 1"=80' 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. TP-1 TP-1 TP-2 TP-3 TP-4 TP-5 S.E. 2ND PLACE 460 450 460 450 DocuSign Envelope ID: 121137F3-D672-460F-8802-55F5D3EB78FE Drwn.MRS Checked CGH Date Nov.2021 Date 11/01/2021 Proj.No.8178 Plate 3 Earth Solutions NWLLCEarthSolutionsNWLLC EarthSolutions NW LLC Geotechnical Engineer ing,C onstr uction Observation/Testing and Environmental Services Retaining Wall Drainage Detail 2nd Place Short Plat 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: 121137F3-D672-460F-8802-55F5D3EB78FE Drwn.MRS Checked CGH Date Nov.2021 Date 11/01/2021 Proj.No.8178 Plate 4 Earth Solutions NWLLC Geotechnical Engineering,Construction Observation/Testing and Environmental Services EarthSolutionsNWLLC EarthSolutions NW LLC Footing Drain Detail 2nd Place Short Plat 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: 121137F3-D672-460F-8802-55F5D3EB78FE Earth Solutions NW, LLC Appendix A Subsurface Exploration Test Pit Logs ES-8178 An ESNW representative observed, logged, and sampled five test pits on September 27, 2021. The explorations were completed in accessible site areas using a trackhoe and operator retained by our firm. The test pits were excavated to a maximum exploration depth of about nine feet bgs. The approximate locations of the test pits are depicted on Plate 2 (Test Pit Location Plan). The test pit logs are provided in this Appendix. 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: 121137F3-D672-460F-8802-55F5D3EB78FE 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: 121137F3-D672-460F-8802-55F5D3EB78FE MC = 35.5% Fines = 25.5% MC = 10.6% MC = 12.6% MC = 9.5% TPSL SM SP- SM SM Dark brown TOPSOIL, roots to 3' Brown silty SAND with gravel, loose to moist to wet [USDA Classification: gravelly fine sandy LOAM] -becomes gray, dense Gray poorly graded SAND with silt and gravel, very dense, wet -moderate perched groundwater seepage -trace cobbles Gray silty SAND, very dense, moist to wet -moderate iron oxide staining Test pit terminated at 9.0 feet below existing grade. Groundwater seepage encountered at 4.75 feet during excavation. No caving observed. 1.0 4.0 6.0 9.0 NOTES Depth of Topsoil & Sod 12": grass LOGGED BY CGH EXCAVATION METHOD EXCAVATION CONTRACTOR NW Excavating CHECKED BY SSR DATE STARTED 9/27/21 COMPLETED 9/27/21 GROUND WATER LEVEL: GROUND ELEVATION ~465 LONGITUDE -122.13322 LATITUDE 47.48146 AT TIME OF EXCAVATION SAMPLE TYPENUMBERDEPTH(ft)0 5 PAGE 1 OF 1 TEST PIT NUMBER TP-1 PROJECT NUMBER ES-8178 PROJECT NAME 2nd Place Short Plat GENERAL BH / TP / WELL - 8178.GPJ - GRAPHICS TEMPLATE.GDT - 11/2/21Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711 TESTS U.S.C.S.MATERIAL DESCRIPTION GRAPHICLOGDocuSign Envelope ID: 121137F3-D672-460F-8802-55F5D3EB78FE MC = 4.1% Fines = 12.2% MC = 7.2% MC = 11.4% TPSL GM SM Dark brown TOPSOIL, roots to 4' Brown silty GRAVEL with sand, loose, damp -becomes gray [USDA Classification: extremely gravelly sandy LOAM] Gray silty SAND with gravel, very dense, moist -heavy iron oxide staining at 4' Test pit terminated at 8.0 feet below existing grade. Groundwater seepage encountered at 4.0 feet during excavation. No caving observed. 0.5 4.0 8.0 NOTES Depth of Topsoil & Sod 6": grass LOGGED BY CGH EXCAVATION METHOD EXCAVATION CONTRACTOR NW Excavating CHECKED BY SSR DATE STARTED 9/27/21 COMPLETED 9/27/21 GROUND WATER LEVEL: GROUND ELEVATION ~460 LONGITUDE -122.13339 LATITUDE 47.48133 AT TIME OF EXCAVATION SAMPLE TYPENUMBERDEPTH(ft)0 5 PAGE 1 OF 1 TEST PIT NUMBER TP-2 PROJECT NUMBER ES-8178 PROJECT NAME 2nd Place Short Plat GENERAL BH / TP / WELL - 8178.GPJ - GRAPHICS TEMPLATE.GDT - 11/2/21Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711 TESTS U.S.C.S.MATERIAL DESCRIPTION GRAPHICLOGDocuSign Envelope ID: 121137F3-D672-460F-8802-55F5D3EB78FE MC = 9.3% MC = 14.9% Fines = 23.6% MC = 11.8% MC = 9.9% Fines = 16.5% TPSL SM Dark brown TOPSOIL, roots Brown silty SAND, loose, damp to moist -becomes gray, dense -6" thick sand/gravel lens, heavy iron oxide staining [USDA Classification: gravelly sandy LOAM] -weakly cemented -minor to moderate perched groundwater seepage -becomes silty sand with gravel [USDA Classification: very gravelly loamy SAND] Test pit terminated at 9.0 feet below existing grade. Groundwater seepage encountered at 8.0 feet during excavation. No caving observed. 1.0 9.0 NOTES Depth of Topsoil & Sod 12": grass LOGGED BY CGH EXCAVATION METHOD EXCAVATION CONTRACTOR NW Excavating CHECKED BY SSR DATE STARTED 9/27/21 COMPLETED 9/27/21 GROUND WATER LEVEL: GROUND ELEVATION ~458 LONGITUDE -122.13316 LATITUDE 47.48123 AT TIME OF EXCAVATION SAMPLE TYPENUMBERDEPTH(ft)0 5 PAGE 1 OF 1 TEST PIT NUMBER TP-3 PROJECT NUMBER ES-8178 PROJECT NAME 2nd Place Short Plat GENERAL BH / TP / WELL - 8178.GPJ - GRAPHICS TEMPLATE.GDT - 11/2/21Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711 TESTS U.S.C.S.MATERIAL DESCRIPTION GRAPHICLOGDocuSign Envelope ID: 121137F3-D672-460F-8802-55F5D3EB78FE MC = 23.3% MC = 9.4% MC = 15.3% Fines = 27.0% SM SM Dark brown silty SAND, loose, moist (Fill) -roots to 3' -garden hose/plastic debris -6" thick relic topsoil horizon at south edge of test pit Brown silty SAND with gravel, loose to medium dense, moist -becomes gray, dense to very dense -moderate iron oxide staining -minor to moderate perched groundwater seepage [USDA Classification: gravelly sandy LOAM] Test pit terminated at 8.0 feet below existing grade. Groundwater seepage encountered at 6.0 feet during excavation. No caving observed. 2.5 8.0 NOTES Depth of Topsoil & Sod 4": light brush LOGGED BY CGH EXCAVATION METHOD EXCAVATION CONTRACTOR NW Excavating CHECKED BY SSR DATE STARTED 9/27/21 COMPLETED 9/27/21 GROUND WATER LEVEL: GROUND ELEVATION ~442 LONGITUDE -122.13409 LATITUDE 47.48157 AT TIME OF EXCAVATION SAMPLE TYPENUMBERDEPTH(ft)0 5 PAGE 1 OF 1 TEST PIT NUMBER TP-4 PROJECT NUMBER ES-8178 PROJECT NAME 2nd Place Short Plat GENERAL BH / TP / WELL - 8178.GPJ - GRAPHICS TEMPLATE.GDT - 11/2/21Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711 TESTS U.S.C.S.MATERIAL DESCRIPTION GRAPHICLOGDocuSign Envelope ID: 121137F3-D672-460F-8802-55F5D3EB78FE MC = 10.9% Fines = 25.4% MC = 5.9% MC = 12.2% SM SM Dark brown silty SAND with gravel, loose, moist (Fill) -roots to 4', areas of increased organics within the fill Brown silty SAND, loose to medium dense, moist [USDA Classification: gravelly sandy LOAM] -becomes gray, very dense -very weakly cemented Test pit terminated at 9.0 feet below existing grade. No groundwater encountered during excavation. No caving observed. 1.0 9.0 NOTES Depth of Topsoil & Sod 12": grass LOGGED BY CGH EXCAVATION METHOD EXCAVATION CONTRACTOR NW Excavating CHECKED BY SSR DATE STARTED 9/27/21 COMPLETED 9/27/21 GROUND WATER LEVEL: GROUND ELEVATION ~465 LONGITUDE -122.13361 LATITUDE 47.48145 AT TIME OF EXCAVATION SAMPLE TYPENUMBERDEPTH(ft)0 5 PAGE 1 OF 1 TEST PIT NUMBER TP-5 PROJECT NUMBER ES-8178 PROJECT NAME 2nd Place Short Plat GENERAL BH / TP / WELL - 8178.GPJ - GRAPHICS TEMPLATE.GDT - 11/2/21Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711 TESTS U.S.C.S.MATERIAL DESCRIPTION GRAPHICLOGDocuSign Envelope ID: 121137F3-D672-460F-8802-55F5D3EB78FE Earth Solutions NW, LLC Appendix B Laboratory Test Results ES-8178 DocuSign Envelope ID: 121137F3-D672-460F-8802-55F5D3EB78FE 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 25.5 12.2 23.6 16.5 27.0 101/2 COBBLES Specimen Identification 4 coarse 20 401.5 8 14 USDA: Brown Gravelly Fine Sandy Loam. USCS: SM with Gravel. USDA: Gray Extremely Gravelly Sandy Loam. USCS: GM with Sand. USDA: Gray Gravelly Sandy Loam. USCS: SM. USDA: Gray Very Gravelly Loamy Sand. USCS: SM with Gravel. USDA: Gray Gravelly Sandy Loam. USCS: SM. 6 60 PERCENT FINER BY WEIGHTD10 0.09 0.59 0.109 0.215 0.089 0.394 19.12 0.487 2.678 0.421 GRAIN SIZE DISTRIBUTION 100 328.84 LL TP-01 TP-02 TP-03 TP-03 TP-04 3/4 U.S. SIEVE OPENING IN INCHES U.S. SIEVE NUMBERS GRAVEL SAND 37.5 37.5 19 37.5 19 %Silt 0.31 TP-01 TP-02 TP-03 TP-03 TP-04 2 2003 Cc CuClassification %Clay 16 PID60 D30 coarse SILT OR CLAYfinemedium GRAIN SIZE IN MILLIMETERS 3/8 50 2.0ft. 2.0ft. 6.0ft. 9.0ft. 8.0ft. 2.00ft. 2.00ft. 6.00ft. 9.00ft. 8.00ft. PL PROJECT NUMBER ES-8178 PROJECT NAME 2nd Place Short Plat GRAIN SIZE USDA ES-8178 2ND PLACE SHORT PLAT.GPJ GINT US LAB.GDT 10/11/21Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711 DocuSign Envelope ID: 121137F3-D672-460F-8802-55F5D3EB78FE 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 25.4 101/2 COBBLES Specimen Identification 4 coarse 20 401.5 8 14 USDA: Brown Gravelly Sandy Loam. USCS: SM with Gravel. 6 60 PERCENT FINER BY WEIGHTD10 0.0990.643 GRAIN SIZE DISTRIBUTION 100 LL TP-05 3/4 U.S. SIEVE OPENING IN INCHES U.S. SIEVE NUMBERS GRAVEL SAND 19 %Silt TP-05 2 2003 Cc CuClassification %Clay 16 PID60 D30 coarse SILT OR CLAYfinemedium GRAIN SIZE IN MILLIMETERS 3/8 50 2.0ft. 2.00ft. PL PROJECT NUMBER ES-8178 PROJECT NAME 2nd Place Short Plat GRAIN SIZE USDA ES-8178 2ND PLACE SHORT PLAT.GPJ GINT US LAB.GDT 10/11/21Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711 DocuSign Envelope ID: 121137F3-D672-460F-8802-55F5D3EB78FE Earth Solutions NW, LLC Report Distribution ES-8178 EMAIL ONLY SAA Ventures, LLC 6463 – 167th Lane Southeast Bellevue, Washington 98006 Attention: Mr. Ravikumar Mandaleeka Mr. Kiran Komaravolu EMAIL ONLY DMP, Inc. 726 Auburn Way North Auburn, Washington 98002 Attention: Mr. Hans Korve DocuSign Envelope ID: 121137F3-D672-460F-8802-55F5D3EB78FE