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HomeMy WebLinkAboutRS_Geotechnical_Report_170807_v1EarthSolutionsNWLLC EarthSolutions NW LLC Geotechnical Engineering Geology Environmental Scientists Construction Monitoring 1805 -136th Place N.E.,Suite 201 Bellevue,WA 98005 (425)449-4704 Fax (425)449-4711 www.earthsolutionsnw.com GEOTECHNICAL ENGINEERING STUDY PROPOSED COMMERCIAL DEVELOPMENT TALBOT ROAD SOUTH AND SOUTH 45th PLACE RENTON,WASHINGTON ES-0895.03 V", K ,4*?- * ■ T'-P ■j-■■■= ¥ m 3=Ss ss a■ '-5r' sft :+'-- 5£it ,_■* T « r Hnr. / "=■--- gu rC .- +'' Lr ’a4^■■ ■■-A.-/-*r ' -r_^>--f1 ■’■■*;*-^s-rrasa - ~-*■■,' £■*»■ ' _- > PREPARED FOR RJ DEVELOPMENT, LLC August 3, 2017 CllfirLs (?■ Chase G. Halsen Staff Geologist "3 ttS.giagel, L.E. Senior Project Manager v £WA0*hi•V '.5?. fc>NAL Kyle R. Campbell, P.E. Principal GEOTECHNICAL ENGINEERING STUDY PROPOSED COMMERCIAL DEVELOPMENT TALBOT ROAD SOUTH AND SOUTH 45th PLACE RENTON, WASHINGTON ES-0895.03 Earth Solutions NW, LLC 1805 - 136th Place Northeast, Suite 201 Bellevue, Washington 98005 Phone: 425-449-4704 Fax: 425-449-4711 Toll Free: 866-336-8710 Important Information About Your — Geotechnical Engineering Report—, Subsurface problems are a principal cause of construction delays, cost overruns, claims, and disputes. The following information is provided to help you manage your risks. Geotechnical Services Are Performed for Specific Purposes, Persons, and Projects Geotechnical engineers structure their services to meet the specific needs of their clients. A geotechnical engineering study conducted for a civil engi­ neer may not fulfill the needs of a construction contractor or even another civil engineer. Because each geotechnical engineering study is unique, each geotechnical engineering report is unique, prepared so/e/yforthe client. No one except you should rely on your geotechnical engineering report without first conferring with the geotechnical engineer who prepared it. And no one —not even you—should apply the report for any purpose or project except the one originally contemplated. Read the Full Report Serious problems have occurred because those relying on a geotechnical engineering report did not read it all, Do not rely on an executive summary. Do not read selected elements only. A Geotechnical Engineering Report Is Based on A Unique Set of Project-Specific Factors Geotechnical engineers consider a number of unique, project-specific fac­ tors when establishing the scope of a study. Typical factors include: the client's goals, objectives, and risk management preferences; the general nature of the structure involved, its size, and configuration; the location of the structure on the site; and other planned or existing site improvements, such as access roads, parking lots, and underground utilities. Unless the geotechnical engineer who conducted the study specifically indicates oth­ erwise, do not rely on a geotechnical engineering report that was: • not prepared for you, • not prepared for your project, • not prepared for the specific site explored, or • completed before important project changes were made. Typical changes that can erode the reliability of an existing geotechnical engineering report include those that affect: • the function of the proposed structure, as when it's changed from a parking garage to an office building, or from a light industrial plant to a refrigerated warehouse, • elevation, configuration, location, orientation, or weight of the proposed structure, • composition of the design team, or • project ownership. As a general rule, always inform your geotechnical engineer of project changes—even minor ones—and request an assessment of their impact. Geotechnical engineers cannot accept responsibility or liability for problems that occur because their reports do not consider developments of which they were not informed. Subsurface Conditions Can Change A geotechnical engineering report is based on conditions that existed at the time the study was performed. Do not rely on a geotechnical engineer­ ing report whose adequacy may have been affected by: the passage of time; by man-made events, such as construction on or adjacent to the site; or by natural events, such as floods, earthquakes, or groundwater fluctua­ tions. Always contact the geotechnical engineer before applying the report to determine if it is still reliable. A minor amount of additional testing or analysis could prevent major problems. Most Geotechnical Findings Are Professional Opinions Site exploration identifies subsurface conditions only at those points where subsurface tests are conducted or samples are taken. Geotechnical engi­ neers review field and laboratory data and then apply their professional judgment to render an opinion about subsurface conditions throughout the site. Actual subsurface conditions may differ-sometimes significantly— from those indicated in your report. Retaining the geotechnical engineer who developed your report to provide construction observation is the most effective method of managing the risks associated with unanticipated conditions. A Report's Recommendations Are Not Final Do not overrely on the construction recommendations included in your report. Those recommendations are not final, because geotechnical engi­ neers develop them principally from judgment and opinion. Geotechnical engineers can finalize their recommendations only by observing actual subsurface conditions revealed during construction. The geotechnical engineer who developed your report cannot assume responsibility or liability for the report's recommendations if that engineer does not perform construction observation. A Geotechnical Engineering Report is Subject to Misinterpretation Other design team members' misinterpretation of geotechnical engineering reports has resulted in costly problems. Lower that risk by having your geo­ technical engineer confer with appropriate members of the design team after submitting the report. Also retain your geotechnical engineer to review perti­ nent elements of the design team's plans and specifications, Contractors can also misinterpret a geotechnical engineering report. Reduce that risk by having your geotechnical engineer participate in prebid and preconstruction conferences, and by providing construction observation. Do Not Redraw the Engineer's Logs Geotechnical engineers prepare final boring and testing logs based upon their interpretation of field logs and laboratory data. To prevent errors or omissions, the logs included in a geotechnical engineering report should never be redrawn for inclusion in architectural or other design drawings. Only photographic or electronic reproduction is acceptable, but recognize that separating logs from the report can elevate risk. Give Contractors a Complete Report and Guidance Some owners and design professionals mistakenly believe they can make contractors liable for unanticipated subsurface conditions by limiting what they provide for bid preparation. To help prevent costly problems, give con­ tractors the complete geotechnical engineering report, but preface it with a clearly written letter of transmittal. In that letter, advise contractors that the report was not prepared for purposes of bid development and that the report's accuracy is limited; encourage them to confer with the geotechnical engineer who prepared the report (a modest fee may be required) and/or to conduct additional study to obtain the specific types of information they need or prefer. A prebid conference can also be valuable. Be sure contrac­ tors have sufficient time to perform additional study. Only then might you be in a position to give contractors the best information available to you, while requiring them to at least share some of the financial responsibilities stemming from unanticipated conditions. Read Responsibility Provisions Closely Some clients, design professionals, and contractors do not recognize that geotechnical engineering is far less exact than other engineering disci­ plines. This lack of understanding has created unrealistic expectations that V_______________________ have led to disappointments, claims, and disputes. To help reduce the risk of such outcomes, geotechnical engineers commonly include a variety of explanatory provisions in their reports. Sometimes labeled "limitations" many of these provisions indicate where geotechnical engineers’ responsi­ bilities 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 equipment, techniques, and personnel used to perform a geoenviron­ mental study differ significantly from those used to perform a geotechnical study. For that reason, a geotechnical engineering report does not usually relate any geoenvironmental findings, conclusions, or recommendations; e.g., about the likelihood of encountering underground storage tanks or regulated contaminants. Unanticipated environmental problems have led to numerous project failures. If you have not yet obtained your own geoen­ vironmental information, ask your geotechnical consultant for risk man­ agement guidance. Do not rely on an environmental report prepared for someone else. Obtain Professional Assistance To Deal with Mold Diverse strategies can be applied during building design, construction, operation, and maintenance to prevent significant amounts of mold from growing on indoor surfaces. To be effective, all such strategies should be devised for the express purpose of mold prevention, integrated into a com­ prehensive plan, and executed with diligent oversight by a professional mold prevention consultant. Because just a small amount of water or moisture can lead to the development of severe mold infestations, a num­ ber of mold prevention strategies focus on keeping building surfaces dry. While groundwater, water infiltration, and similar issues may have been addressed as part of the geotechnical engineering study whose findings are conveyed in-this report, the geotechnical engineer in charge of this project is not a mold prevention consultant; none of the services per­ formed in connection with the geotechnical engineer’s study were designed or conducted for the purpose of mold preven­ tion. Proper implementation of the recommendations conveyed in this report will not of itself be sufficient to prevent mold from growing in or on the structure involved. Rely, on Your ASFE-Member Geotechncial Engineer for Additional Assistance Membership in ASFE/The Best People on Earth exposes geotechnical engineers to a wide array of risk management techniques that can be of genuine benefit for everyone involved with a construction project. Confer with you ASFE-member geotechnical engineer for more information. _____________________________________________J J-15FE The Best People on Earih 8811 Colesville Road/Suite G106, Silver Spring, MD 20910 Telephone: 301/565-2733 Facsimile: 301/589-2017 e-mail: info@asfe.org www.asfe.org Copyright 2004 by ASFE. Inc. Duplication, reproduction, or copying of this document, in whole or in part, by any means whatsoever, is strictly prohibited, except with ASFE's specific written permission. Excerpting, quoting, or otherwise extracting wording from this document is permitted only with the express written permission of ASFE, and only for purposes of scholarly research or book review. Only members of ASFE may use this document as a complement to or as an element of a geotechnical engineering report. Any other firm, individual, or other entity that so uses this document without being an ASFE member could be committing negligent or intentional (fraudulent) misrepresentation. IIGER06045.0M August 3, 2017 ES-0895.03 1 RJ Development, LLC 401 Central Street Southeast Olympia, Washington 98501 Earth Solutions NW LLC Attention: Mr. Kyle Oster • Geotechnical Engineering • Construction Monitoring • Environmental Sciences Dear Mr. Oster: Earth Solutions NW, LLC (ESNW) is pleased to present this report titled “Geotechnical Engineering Study, Proposed Commercial Development, Talbot Road South and South 45th Place, Renton, Washington”. Based on review of our previously performed investigations, the proposed commercial development is feasible from a geotechnical standpoint. Our study indicates the site is underlain primarily by undifferentiated glacial deposits (Qu). During the subsurface exploration completed on November 18, 2006, groundwater seepage was identified at some of the test pit locations, at a depth of about two feet below existing grades. As such, the contractor should be prepared to respond to groundwater seepage during construction. In our opinion, proposed commercial structures may be constructed on conventional continuous and spread footing foundations bearing upon competent native soil, recompacted native soil, or new structural fill. In general, competent native soil suitable for support of foundations will likely be encountered at an approximate depth of three to five feet below existing grades. Where loose or unsuitable soil conditions are exposed at foundation subgrade elevations, compaction of soils to the specifications of structural fill, or overexcavation and replacement with suitable structural fill, will be necessary. We presume that surface water generated from new site surfaces will be managed through the implementation of a stormwater detention vault (vault) located on-site. Based on our field observations, grade cuts for the vault are likely to expose very dense, undisturbed native soils. It is our opinion the native fine-grained deposits should not be considered an ideal geologic feature for accommodation of infiltration facilities, especially when encountered in a dense, compact state. In general, the native fine-grained deposits should be considered impervious for practical design purposes. Pertinent geotechnical recommendations are provided in this study. We appreciate the opportunity to be of service to you on this project. If you have questions regarding the content of this geotechnical engineering study, please call. Sincerely, EARTH SOLUTIONS NW, LLC Chase G. Halsen Staff Geologist 1805 - 136lh Place N.E., Suite 201 • Bellevue, WA 98005 • (425)449-4704 • FAX (425) 449-4711 Table of Contents ES-0895.03 PAGE INTRODUCTION................................................................................................... 1 General...................................................................................................... 1 Project Description.................................................................................. 2 SITE CONDITIONS................................................................................................ 2 Surface.................................................................................................... 2 Subsurface................................................................................................ 3 Topsoil and Fill.............................................................................. 3 Native Soil..................................................................................... 3 Geologic Setting........................................................................... 3 Groundwater............................................................................................. 4 GEOLOGICALLY HAZARDOUS AREAS..................................................... 4 Steep Slope Hazard........................................................................... 4 Landslide Hazard............................................................................... 5 Erosion Hazard.................................................................................. 5 DISCUSSION AND RECOMMENDATIONS................................................... 6 General............................................................................................... 6 Site Preparation and Earthwork....................................................... 6 Temporary Erosion Control.................................................. 7 Stripping................................................................................. 7 Excavations and Slopes........................................................ 7 In-situ and Imported Soils..................................................... 8 Subgrade Preparation........................................................... 8 Structural Fill.......................................................................... 9 Foundations..................................................................................... 9 Seismic Design.................................................................................. 10 Slab-on-Grade Floors........................................................................ 10 Retaining Walls................................................................................ 10 Drainage............................................................................................. 11 Preliminary Infiltration Feasibility........................................ 12 Preliminary Pavement Sections....................................................... 12 Utility Support and Trench Backfill.................................................. 13 LIMITATIONS.................................................................................................. 13 Additional Services............................................................................ 13 Earth Solutions NW, LLC Table of Contents Cont’d ES-0895.03 GRAPHICS Plate 1 Vicinity Map Plate 2 Test Pit Location Plan Plate 3 Retaining Wall Drainage Detail Plate 4 Footing Drain Detail APPENDICES Appendix A Subsurface Exploration Test Pit Logs Appendix B Laboratory Test Results Earth Solutions NW, LLC GEOTECHNICAL ENGINEERING STUDY PROPOSED COMMERCIAL DEVELOPMENT TALBOT ROAD SOUTH AND SOUTH 45th PLACE RENTON, WASHINGTON ES-0895.03 INTRODUCTION General This geotechnical engineering study (study) was prepared for the proposed commercial development to be completed east of the intersection between Talbot Road South and South 45sh Place in Renton, Washington. The purpose of this study was to provide geotechnical recommendations for currently proposed development plans. Our scope of services for completing this study included the following: • Conducting a site visit to observe current conditions; • Review of previously performed test pits for purposes of characterizing site soil and groundwater conditions; • Review of laboratory testing results of soil samples collected at the test pit locations; • Conducting engineering analyses, and; • Preparation of this report. The following documents and maps were reviewed as part of our study preparation: • Boundary and Topographic Survey, prepared by Barghausen Consulting Engineers, Inc., dated January 25, 2008; • Title 4-3-050 of the Renton Municipal Code; • Steep Slope, Landslide Hazard, and Erosion Hazard Sensitive Areas Maps, maintained by the City of Renton, dated November 12, 2014; • Online Web Soil Survey (WSS) resource, maintained by the Natural Resources Conservation Service under the United States Department of Agriculture; • King County Liquefaction Susceptibility, endorsed by the King County Flood Control District, May 2010, and; • Geologic Map of the Renton Quadrangle, Washington, by D.R. Mullineaux, 1965. RJ Development, LLC August 3, 2017 ES-0895.03 Page 2 Project Description Formal site layout and grading plans were not available for review at the time of this report preparation, We anticipate the site will be redeveloped with a commercial building and related infrastructure improvements. At the time of report submission, specific building load and grading plans were not available for review; however, based on our experience, we anticipate that the site will be developed with commercial structure(s). We presume the structures will incorporate the use of conventional foundations, We anticipate cuts and/or fills of about 5 to 10 feet may be necessary to establish finish grade elevations. We expect cuts to achieve a typical vault subgrade elevation may be up to about 10 to 15 feet. Retaining walls and/or rockeries may be incorporated into final designs to accommodate grade transitions, where necessary. We presume stormwater management plans will include a vault located on site. If the above design assumptions are incorrect or change, 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 east of the intersection between Talbot Road South and South 45th Place in Renton, Washington. The approximate location of the subject site is depicted on Plate 1 (Vicinity Map). The rectangular property is comprised of two adjoining tax parcels (King County Parcel Nos. 312305-9094, and -9067) totaling approximately 4.63 acres. The site is bordered to the north and south by existing commercial and residential development, and to the east by undeveloped land and to the west by Talbot Road South. A single-family residence once occupied the northern site area but appears to have been demolished and removed from the property. The existing access road, however, still remains. Topography generally ascends gently to the east. The eastern site area maintains a general gradient of 30 percent while the central and western site area maintains a flatter gradient, on the order of approximately 10 percent. As observed during our August 2017 site visit, the property appears to be relatively un-changed from the previously performed explorations completed by our firm (November 2006 and May 2007). Earth Solutions NW, LLC RJ Development, LLC August 3, 2017 ES-0895.03 Page 3 Subsurface An ESNW representative observed, logged, and sampled six test pits excavated within the southern parcel (ES-0690) on November 18, 2006, as well as five test pits excavated within the northern parcel (ES-0895) on May 23, 2007. The test pits were excavated at accessible locations within the property boundaries using an excavator and operator retained by our firm. The test pits were completed for purposes of assessment and classification of site soils as well as characterization of groundwater conditions within accessible areas of the site. The approximate locations of the test pits are depicted on Plate 2 (Test Pit Location Plan). Please refer to the test pit logs provided in Appendix A for a more detailed description of subsurface conditions. Representative soil samples collected at the test pit locations were analyzed in accordance with both Unified Soil Classification System (USCS) and United States Department of Agriculture (USDA) methods and procedures. Topsoil and Fill Where encountered, topsoil was in the upper 12 to 18 inches of existing grades at the test pit locations. The topsoil was characterized by dark brown color, the presence of fine organic material, and small root intrusions. Deeper pockets of topsoil, however, may be encountered locally across the site. Fill was not encountered during our subsurface explorations. However, fill should be anticipated in proximity to current and existing site features. ESNW can evaluate in-situ fill where encountered during construction, as needed. Native Soil Underlying topsoil, native soils were encountered consisting primarily of silty sand (USCS: SM). The upper, loose to medium dense deposits may be characterized as “weathered”, and the lower, dense to very dense deposits were characterized as “unweathered”. Layers of silt, sand, and gravel soil types were also observed within some test pit locations. Native soils were observed primarily in a moist condition and extended to the maximum exploration depth of approximately 18 feet below the existing ground surface (bgs). Geologic Setting The referenced geologic map resource identifies Ground Moraine Deposits (Qgt) across the site and surrounding areas. According to the geologic map resource, moraine deposits are chiefly ablation till over lodgment till, characterized as an unsorted mixture of sand, silt, clay, and gravel. Moraine deposits are primarily compact and is commonly referred to as “hardpan”. However, based on the previously performed subsurface explorations, the layers of silt, sand, and gravel soils are indicative of a interglacial undifferentiated deposits (Qu), as mapped directly east of the subject site. The geologic map resource characterizes undifferentiated deposits as till sheets, glaciofluvial sand and gravel, glaciolacustrine clay and sand, and non­ glacial sand, clay, and thin peat. The referenced WSS resource identifies Alderwood gravelly sandy loam (Map Unit Symbols: AgC and AgD) across the site and surrounding areas. The Alderwood series was formed in glacial deposits and is present primarily in ridges and hills. Based on our field observations, native soils likely to be exposed during grading activities will be consistent with the geologic setting outlined of undifferentiated glacial deposits as outlined in this section. Earth Solutions NW, LLC RJ Development, LLC August 3, 2017 ES-0895.03 Page 4 Groundwater During our subsurface exploration completed in November 2006, groundwater seepage was identified at some test pit locations at about two feet below existing grades. As such, it is our opinion groundwater is likely to be encountered during subsequent construction activities, and the contractor should be prepared to respond as appropriate. 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 wetter, winter months. GEOLOGICALLY HAZARDOUS AREAS To assess the presence of geologically hazardous areas on-site, we reviewed critical area maps maintained by the City of Renton (City), Renton Municipal Code (RMC) Title 4-3-050, and the referenced topographic survey to ascertain approximate site gradients. Steep Slope Hazard Review of the City Steep Slope Hazard Map indicates a portion of the eastern site area as containing a sensitive slope area. RMC Title 4-3-050 provides criteria for slope designations, and are as follows: * Sensitive slopes: A hillside, or portion thereof, characterized by: (a) an average slope of 25 percent to less than 40 percent as identified in the city of Renton Steep Slope Atlas or in a method approved by the City or (b) an average slope of 40 percent or greater with a vertical rise of less than 15 feet as identified in the City of Renton Steep Slope Atlas or in a method approved by the City; (c) abutting an average slope of 25 to 40 percent as identified in the City of Renton Steep Slope Atlas or in a method approved by the City. This definition excludes engineered retaining walls. • Protected Slopes: A hillside, or portion thereof, characterized by an average slope of 40 percent or greater grade and having a minimum vertical rise of 15 feet as identified in the City of Renton Steep Slope Atlas or in a method approved by the City. Based on review of grade delineations on the referenced topographic survey, a majority of the eastern site sloping feature may be considered a sensitive slope (gradients between 25 and 40 percent) in accordance with RMC Title 4-3-050. Isolated areas of the slope may be considered a protected slope due to the presence of grades in excess of 40 percent over a vertical rise of at least 15 feet (northeastern site corner). Buffers and building setbacks from critical areas are largely established on the basis of findings and recommendations from the results of a critical area study, pending approval or alteration by the City building official or to comply with building codes. In this regard, it is our opinion that no buffer or building setback need be applied to areas of the site considered a sensitive slope. Likewise, areas of the site considered a protected slope, in our opinion, will not require a buffer. However, a mandated building setback of 15 feet from areas of the protected slope will be required. In general, structural elements will be supported either on competent cuts, or on structural fill placed directly on competent native soils. If the proposed structure(s) utilize stepped foundations, the potential building area may be expanded further into the eastern site area while not adversely affect the stability of the identified slopes on-site or immediately adjacent to the property. Earth Solutions NW, LLC RJ Development, LLC August 3, 2017 ES-0895.03 Page 5 Landslide Hazard Review of the City Landslide Hazard Map indicates a portion of the eastern site area as containing a medium potential landslide hazard. RMC Title 4-3-050 provides criteria for landslide hazard designations, and are as follows: • Medium Landslide Hazard: Areas with slopes between 15 and 40 percent and underlain by soils that consist largely of sand, gravel, or glacial till. • High Landslide Hazard: Areas with slopes greater than 40 percent, and areas with slopes between 15 percent and 40 percent and underlain by soil consisting largely of silt and clay. Native soils encountered during our previous subsurface explorations indicate that the site and surrounding area as being underlain by glacially consolidated deposits. In general, the eastern slope feature contains an average gradient between 15 and 40 percent. Therefore majority of this area may be considered a medium landslide hazard in accordance to City codes. With the presence of grades in excess of 40 percent, areas of the slope within the northeastern site corner may also be considered a high landslide hazard. No buffer or building setback has been required for medium and high landslide hazard areas, and in our opinion, none need to be required. Provided the proposed structures utilized stepped foundations, or incorporate temporary/permanent shoring to establish a level finish floor elevation, it is our opinion that the proposed development will not adversely affect the potential for the occurrence of a landslide hazards on-site. Erosion Hazard Review of the City Erosion Hazard Map indicates that no areas of the site have been identified with such a hazard. As defined within RMC Title 4-3-050, erosion hazards are characterized as: • Low Erosion Hazard: Areas with soils characterized by the Natural Resource Conservation Service (formerly U.S. Soil Conservation Service) as having slight or moderate erosion potential, and a slope less than 15 percent. • High Erosion Hazard: Areas with soil characterized by the Natural Resource Conservation Service (formerly U.S. Soil Conservation Service) as having severe or very severe erosion potential, and a slope more than 15 percent. The referenced WSS resource indication soils of the Alderwood gravelly sandy loam series (Map Unit Symbol: AgC and AgD) as underlying the subject site and surrounding area. In general, these soils are considered to have a moderate erosion potential. In general, slopes exhibiting an inclination greater than 15 percent may be characterized as being a high erosion hazard. In our opinion, with the present soil types and average gradient across the site, it is our opinion that the site possess and moderate erosion hazard potential. Erosion can be controlled through the use of temporary and permanent erosion and sediment control (ESC) measures. Earth Solutions NW, LLC RJ Development, LLC August 3, 2017 ES-0895.03 Page 6 Provided such measures are incorporated into final designs, it is our opinion that the potential for erosion will remain low both during and after construction. Site-specific ESC measures are typically specified by the project civil engineer during design. Upon finalization, ESNW should have the opportunity to review site layout and grading plans to ensure that our recommendations pertaining to geologic hazards on-site have been accounted for. DISCUSSION AND RECOMMENDATIONS General Based on the results of our investigation, construction of a commercial development is feasible from a geotechnical standpoint. The primary geotechnical considerations associated with the proposed development include foundation support, maintaining slope stability, slab-on-grade subgrade support, and the suitability of using on-site soils as structural fill. In our opinion, typical commercial structures on the site may be constructed on conventional continuous and spread footing foundations bearing upon competent native soil, recompacteci native soil, or new structural fill placed directly on competent native soil. In general, competent native soil suitable for support of foundations will likely be encountered at depths of three to five feet below existing grades. Where loose or unsuitable soil conditions are exposed at foundation subgrade elevations, compaction of soils to the specifications of structural fill, or overexcavation and replacement with suitable structural fill, will be necessary. We presume that surface water generated from new site surfaces will be managed through the implementation of a stormwater detention vault (vault) located on-site. Grade cuts for the vault are likely to expose competent native soils. It is our opinion the native fine-grained deposits should not be considered an ideal geologic feature for accommodation of infiltration facilities, especially when encountered in a dense, compact state. In general, the fine-grained deposits should be considered impervious for practical design purposes. This study has been prepared for the exclusive use of RJ Development, LLC and their representatives. No warranty, expressed or implied, is made. This study has been prepared in a manner consistent with the level of care and skill ordinarily exercised by other members of the profession currently practicing under similar conditions in this area. Site Preparation and Earthwork Initial site preparation activities will consist of installing temporary erosion control measures, establishing grading limits, performing clearing and site stripping (as necessary), and removing existing site features. Subsequent earthwork activities will involve mass site grading and related infrastructure improvements. Earth Solutions NW, LLC RJ Development, LLC August 3, 2017 ES-0895.03 Page 7 Temporary Erosion Control Prior to the installation of either initial or final pavement sections, temporary construction entrances and drive lanes, consisting of at least six inches of quarry spalls, should be considered in order to both minimize off-site soil tracking and provide a stable access entrance surface. Geotextile fabric may also be considered underlying the quarry spalls for greater stability of the temporary construction entrance. Erosion control measures should consist of silt fencing placed around the site perimeter. Soil stockpiles should be covered or otherwise protected to reduce soil erosion. Temporary approaches for controlling surface water runoff should be established prior to beginning earthwork activities. Additional Best Management Practices (BMPs), as specified by the project civil engineer and indicated on the plans, should be incorporated into construction activities. Stripping Where present, topsoil was encountered generally within the upper 12 to 18 inches of existing grades at the test pit locations. ESNW should be retained to observe site stripping activities at the time of construction so that the degree of required stripping may be assessed. Over­ stripping should be avoided, as it is unnecessary and may result in increased project development costs. Topsoil and organic-rich soil is neither suitable for foundation support nor for use as structural fill. Topsoil and organic-rich soil may be used in non-structural areas, if desired. Excavations and Slopes Excavation activities are likely to expose both loose to medium dense, weathered soil and dense to very dense soil, unweathered soil. Provided excavations are sloped as recommended below or shored as necessary, the overall stability of the site excavations is anticipated to be good. Based on the soil conditions observed at the test pit 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 and medium dense (weathered) soil 1.5H:1V (Type C) • Areas exposing groundwater seepage 1.5H:1V (Type C) • Dense to very dense (unweathered) soil 0.75H:1V (Type A) Steeper temporary slope inclinations within undisturbed, very dense native deposits, such as those expected within the vault excavation, may be feasible based on the soil and groundwater conditions exposed within the excavations. Steeper inclinations may be considered, and must be subsequently designed, by ESNW at the time of construction. Earth Solutions NW, LLC RJ Development, LLC August 3, 2017 ES-0895.03 Page 8 Permanent slopes should be planted with vegetation to enhance stability and to minimize erosion, and should maintain a gradient of 2H:1V or flatter. The presence of perched groundwater may cause localized sloughing of temporary slopes due to excess seepage forces. An ESNW representative should observe temporary and permanent slopes to confirm the slope inclinations are suitable for the exposed soil conditions and to provide additional excavation and slope recommendations. If the recommended temporary slope inclinations cannot be achieved, temporary shoring may be necessary to support excavations. In-situ and Imported Soils From a geotechnical standpoint, on-site soils may not be suitable for use as structural fill. On­ site soils are moisture sensitive, and successful use as structural fill will largely be dictated by the moisture content at the time of placement and compaction. Remedial measures, such as soil aeration and/or cement treatment (where allowed by the local jurisdiction or utility district), may be necessary as part of site grading and earthwork activities. If the on-site soils 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 (due to over-optimum moisture content) if grading activities take place during periods of extended rainfall activity. Soils with fines contents greater than 5 percent typically degrade rapidly when exposed to periods of rainfall. Imported soil intended for use as structural fill should consist of a well-graded, granular soil with a moisture content that is at (or slightly above) the optimum level. 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 Following site stripping and removal of existing structures and outbuildings, cuts and fills will be completed to establish proposed subgrade elevations across the site. ESNW should observe the subgrade(s) during initial site preparation activities to confirm soil conditions are as anticipated and to provide supplementary recommendations for subgrade preparation, as necessary. The process of removing existing structures may produce voids where old foundations and/or crawl space areas may have been present. Complete restoration of voids resulting from previous or current demolition activities must be executed as part of overall subgrade and building pad preparation activities. The following guidelines for preparing building subgrade areas should be incorporated into the final design: Earth Solutions NW, LLC RJ Development, LLC August 3, 2017 ES-0895.03 Page 9 • Where voids and related demolition disturbances extend below planned subgrade elevations, restoration of these areas should be completed. Structural fill should be used to restore voids or unstable areas resulting from the removal of existing structural elements. • Recompact, or overexcavate and replace, areas of existing fill, if present, exposed at building subgrade elevations. Overexcavations should extend into competent native soils and structural fill should be utilized to restore subgrade elevations as necessary. • ESNW should confirm subgrade conditions, as well as the required level of recompaction and/or overexcavation and replacement, during site preparation activities. ESNW should also evaluate the overall suitability of prepared subgrade areas following site preparation activities. Structural Fill Structural fill is defined as compacted soil placed in foundation, slab-on-grade, and roadway areas. Fill placed to construct permanent slopes and throughout retaining wall and utility trench backfill areas is considered structural fill as well. Soils placed in structural areas should be placed in loose lifts of 12 inches or less and compacted to a relative compaction of 95 percent, based on the laboratory maximum dry density as determined by the Modified Proctor Method (ASTM D1557). For soil placed in utility trenches underlying structural areas, compaction requirements are dictated by the local city, county, or utility district, and are typically specified to a relative compaction of at least 95 percent. Foundations In our opinion, the proposed residential structures may be constructed on conventional continuous and spread footing foundations bearing upon competent native soil, recompacted native soil, or new structural fill. In general, competent native soil suitable for support of foundations will likely be encountered at an approximate depth of three to five feet bgs. Where loose or unsuitable soil conditions are exposed at foundation subgrade elevations, compaction of soils to the specifications of structural fill, or overexcavation and replacement with suitable structural fill, will be necessary. Provided the foundations will be supported as prescribed, the following parameters may be used for design: • Allowable soil bearing capacity 2,500 psf* • Passive earth pressure 300 pcf (equivalent fluid) • Coefficient of friction 0.40 * A higher bearing capacity may be feasible depending on site layout and grading plans and should be evaluated by ESNW Earth Solutions NW, LLC RJ Development, LLC August 3, 2017 ES-0895.03 Page 10 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. The majority of the settlements should occur during construction, as dead loads are applied. Seismic Design The 2015 International Building Code recognizes the American Society of Civil Engineers (ASCE) for seismic site class definitions. In accordance with Table 20.3-1 of the ASCE Minimum Design Loads for Buildings and Other Structures manual, Site Class D should be used for design. The referenced liquefaction susceptibility map indicates the subject site maintains very low liquefaction susceptibility. Liquefaction is a phenomenon where saturated or loose soils suddenly lose internal strength and behave as a fluid. This behavior is in response to increased pore water pressures resulting from an earthquake or other intense ground shaking. In our opinion, site susceptibility to liquefaction may be considered negligible. The relatively consistent densities of the native soils and the absence of a uniformly established, shallow groundwater table were the primary bases for this consideration. Slab-on-Grade Floors Slab-on-grade floors for typical commercial structures should be supported on a well- compacted, firm and unyielding subgrade. Where feasible, native soils exposed at the slab-on- grade subgrade level can likely be compacted in situ to the specifications of structural fill. Unstable or yielding areas of the subgrade should be recompacted, or overexcavated and replaced with suitable structural fill, prior to construction of the slab, A capillary break consisting of a minimum of four inches of free-draining crushed rock or gravel should be placed below the 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. If a vapor barrier is to be utilized, it 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: Earth Solutions NW, LLC RJ Development, LLC August 3, 2017 ES-0895.03 Page 11 • Active earth pressure (yielding condition) • At-rest earth pressure (restrained condition) • Traffic surcharge* (passenger vehicles) • Passive earth pressure • Coefficient of friction • Seismic surcharge * Where applicable ** Where H equals the retained height (in feet) 35 pcf (equivalent fluid) 55 pcf 70 psf (rectangular distribution) 300 pcf (equivalent fluid) 0.40 6H psf** The above design parameters 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 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. Drainage Perched groundwater seepage, as observed at the time of our November 2006 fieldwork, may be encountered in site excavations depending on the time of year grading operations take place, particularly in excavations at depth for utilities and the vault. Temporary measures to control surface water runoff and groundwater during construction would likely involve interceptor trenches and sumps. ESNW should be consulted during preliminary grading to identify areas of seepage and to provide recommendations to reduce the potential for instability related to seepage effects. 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. Earth Solutions NW, LLC RJ Development, LLC August 3, 2017 ES-0895.03 Page 12 Preliminary Infiltration Feasibility As indicated in the Subsurface section of this report, native soils encountered during our fieldwork were characterized primarily as medium dense to very dense silty sand deposits. From a geotechnical standpoint, it is our opinion the native silty sands should not be considered suitable for infiltration, especially when encountered in a dense, compact state. In general, these soils should be considered impervious for practice al design purposes. However, areas where relatively clean sands and gravels (little to no fines content) were encountered during our prior explorations may prove feasible for targeted infiltration devices. However, an additional exploration would like be necessary to determine the extent and feasibility of utilizing these soils for infiltration purposes. As necessary, ESNW can provide further evaluation of, and recommendations for, stormwater flow control BMPs upon request. 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/or placement of thicker crushed rock or structural fill sections, prior to pavement. We anticipate new pavement sections will be subjected primarily to passenger vehicle traffic. 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), or; • 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 WSDOT specifications. All soil base material should be compacted to a relative compaction of 95 percent, based on the laboratory maximum dry density as determined by ASTM D1557. Final pavement design recommendations, including recommendations for heavy traffic areas, access roads, and frontage improvement areas, can be provided once final traffic loading has been determined. Road standards utilized by the City of Renton may supersede the recommendations provided in this report. Earth Solutions NW, LLC RJ Development, LLC August 3, 2017 ES-0895,03 Page 13 Utility Support and Trench Backfill In our opinion, on-site soils will generally be suitable for support of utilities. Remedial measures may be necessary in some areas in order 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, as well as temporary trench shoring, may be necessary during utility excavation and installation. On-site soils may not be suitable for use as structural backfill throughout utility trench excavations unless the soil is at (or slightly above) the optimum moisture content at the time of placement and compaction. Moisture conditioning of the soils 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 specifications of structural fill as previously detailed in this report, or to the applicable specifications of the City of Renton or other responsible jurisdiction or agency. LIMITATIONS 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. A warranty is neither expressed nor implied. Variations in the soil and groundwater conditions at the test pit 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. Earth Solutions NW, LLC Drwn.CAM Checked CGH Date July 2017 Date 07/20/2017 Proj.No.0895.03 Plate 1 Earth Solutions NWLLC Geotechnical Engineering,Construction Monitoring EarthSolutionsNWLLC EarthSolutions NW LLC and Environmental Sciences Vicinity Map Talbot Commercial Renton,Washington Reference: King County,Washington Map 686 By The Thomas Guide Rand McNally 32nd Edition NORTH 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 ^ '■ pvnBik 1™1 * : IWl^ * fl Vum ^ 41.Tt*'!1-1 f.. j — Ti -.5 nm. :E I $ 1IEJ I ■ ■ V3HD u it s A HVf At U ::■" -■ |C,4-!f . S- 1#4 J'h '-■l - I|r1i l! _!S..:*t VI.IT ■■■■ili.-5.£ .. t J Tijj lowd?5*;r * ?^L T23£l: pfc!■ nS-nj Lil-i T2?N■■-■ -■i ■‘■fr..! 'm;h ;.- -■ S l'l=.TH __ s j*-:.:■ IWf % V. fi -■ - 5 1 11 ■' t*" Li :ri- E t CC “f1-1 "'jHI. H */'^ . 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T JLjl, LTl-t-i + =■*«: *^Ur ilIh-*r ,. - ■■■vms f**1IJil!5s ' h wm’s- Jinh Ifnflufi |_ T: .3-, a S£ q ^anlHH LJ $M!f - 1,1 :.= = Bgyjw a ■ ufi j-tWHPC wii ri I'urfi SI" KWlirtT w SL^IJP."W~n—sum n / ■ _-_-«____iffliLL.^i 4* Plate Proj.No. Date Checked By Drwn.By E a r t h S o l u t i o n s N W L L C G e o t e c h n i c a l E n g i n e e r i n g , C o n s t r u c t i o n M o n i t o r i n g a n d E n v i r o n m e n t a l S c i e n c e s E a r t h S o l u t i o n s N W L L C E a r t h S o l u t i o n s N W L L C t a l b o t r d . s . 160 160 170 170 180 180 190 200 210 220 230 240 240230220210200190 TP-1 TP-2 TP-3 TP-4TP-5 TP-6 TP-1 TP-2 TP-3 TP-4 TP-5 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. LEGEND Approximate Location of ESNW Test Pit,Proj.No. ES-0895,May 2007 Approximate Location of ESNW Test Pit,Proj.No. ES-0690,Nov.2006 Subject Site TP-1 NORTH 0 4 0 8 0 1 6 0 Scale in Feet1"=8 0 ' TP-1 CAM CGH 07/20/2017 0895.03 2 T e s t P i t L o c a t i o n P l a n T a l b o t C o m m e r c i a l R e n t o n , W a s h i n g t o n i ! Hi' 11 L V 1 11 ii11ill i mI/1 1!' / / / / / /1 if!iill i /i!i!i ! , i / "/'//// //1!11 1 11 a' i.'ii 1 i V i 11 1 f/Rj/ ii / i1 111 ;1 / 11111 / / ^ 4'-L-u i-1 / Jji7/ I / / ////44///// _v,,/// / / // ! ///y/n!if!(( ' m',. i'ii i / 11 ' ' r y\/ iii< j fin//I I ifl; B;l V WiM/wm'' , , i i11 :■ <■ I 4 11 ' Hi>:1C |^[T I ’ 11 I ll I I 1 1 1 1 I 1 ] R"/ / / / Jir J i I /11 i I 1 1 ' 11,1 K~ - / / / / / - - / / /1111,../// // / / I \ I I i'll I 4* Drwn.CAM Checked CGH Date July 2017 Date 07/20/2017 Proj.No.0895.03 Plate 3 Earth Solutions NWLLC Geotechnical Engineering,Construction Monitoring and Environmental Sciences EarthSolutionsNWLLC EarthSolutions NW LLC RETAINING WALL DRAINAGE DETAIL Talbot Commercial Renton,Washington NOTES: Free Draining Backfill should consist of soil having less than 5 percent fines. Percent passing #4 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" Drain Rock. LEGEND: Free Draining Structural Backfill 1 inch Drain Rock 18"Min. Structural Fill Perforated Drain Pipe (Surround In Drain Rock) SCHEMATIC ONLY -NOT TO SCALE NOT A CONSTRUCTION DRAWING ■■■■■■■■■■■■■, vvvvs ■ ■■■■■■■■■■■■ I Drwn.CAM Checked CGH Date July 2017 Date 07/20/2017 Proj.No.0895.03 Plate 4 Earth Solutions NWLLC Geotechnical Engineering,Construction Monitoring and Environmental Sciences EarthSolutionsNWLLC EarthSolutions NW LLC FOOTING DRAIN DETAIL Talbot Commercial Renton,Washington Slope Perforated Rigid Drain Pipe (Surround with 1"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"Drain Rock SCHEMATIC ONLY -NOT TO SCALE NOT A CONSTRUCTION DRAW ING 7ZZZZZZZZZZZZZZZZZZZZ. m Appendix A Subsurface Exploration Test Pit Logs ES-0895.03 Subsurface conditions at the subject site were explored on November 18, 2006 and May 23, 2007, by excavating a total of 11 test pits using an excavator and operator retained by our firm. The approximate locations of the test pits are illustrated on Plate 2 of this study. The test pit logs are provided in this Appendix. The test pits were advanced to a maximum depth of approximately 18 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. Earth Solutions NW, LLC Earth Solutions NWllc SOIL CLASSIFICATION CHART MAJOR DIVISIONS COARSE GRAINED SOILS MORE THAN 50% OF MATERIAL IS LARGER THAN NO. 200 SIEVE SIZE GRAVEL AND GRAVELLY SOILS MORE THAN 50% OF COARSE FRACTION RETAINED ON NO. 4 SIEVE SAND AND SANDY SOILS MORE THAN 50% OF COARSE FRACTION PASSING ON NO. 4 SIEVE CLEAN GRAVELS (LITTLE OR NO FINES) GRAVELS WITH FINES (APPRECIABLE AMOUNT OF FINES) •• G OQ0OG fit]rOCi 90 CLEAN SANDS (LITTLE OR NO FINES) SANDS WITH FINES (APPRECIABLE AMOUNT OF FINES) SYMBOLS GRAPH LETTER & GW GP GM GC SW SP SM SC 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 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 ML INORGANIC SILTS AND VERY FINE SANDS. ROCK FLOUR, SILTY OR CLAYEY FINE SANDS OR CLAYEY SILTS WITH SLIGHT PLASTICITY FINE GRAINED SOILS MORE THAN 50% OF MATERIAL IS SMALLER THAN NO. 200 SIEVE SIZE SILTS AND CLAYS LIQUID LIMIT LESS THAN 50 CL INORGANIC CLAYS OF LOW TO MEDIUM PLASTICITY, GRAVELLY CLAYS, SANDY CLAYS, SILTY CLAYS, LEAN CLAYS OL ORGANIC SILTS AND ORGANIC SILTY CLAYS OF LOW PLASTICITY SILTS AND CLAYS LIQUID LIMIT GREATER THAN 50 MH INORGANIC SILTS, MICACEOUS OR DIATOMACEOUS FINE SAND OR SILTY SOILS CH INORGANIC CLAYS OF HIGH PLASTICITY OH ORGANIC CLAYS OF MEDIUM TO HIGH PLASTICITY, ORGANIC SILTS if oo O', O', 0'/ O', HIGHLY ORGANIC SOILS PT PEAT, HUMUS, SWAMP SOILS WITH HIGH ORGANIC CONTENTS 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. GE N E R A L B H / T P / W E L L 0 S S 5 . 6 P J G t N T U S G O T 6 / 1 2 / 0 7 9 Earth Solutions NW 2381 152nd Avenue N.E. Redmond, Washington 98052 Telephone: 425-284-3300 Fax: 425-284-2855 TEST PIT NUMBER TP-1 PAGE 1 OF 1 CLIENT JCR Development PROJECT NAME 4518 Talbot Road PROJECT NUMBER 0895 PROJECT LOCATION Renton, Washington DATE STARTED 5/23/07 COMPLETED 5/23/07 GROUND ELEVATION TEST PIT SIZE EXCAVATION CONTRACTOR NW Excavating EXCAVATION METHOD________________________ LOGGED BY SHA_______________ GROUND WATER LEVELS: AT TIME OF EXCAVATION CHECKED BY SHA NOTES Depth of Topsoil & Sod 16" AT END OF EXCAVATION — AFTER EXCAVATION — o. ein Q LU Q. f- HI nr TESTS •0 O MATERIAL DESCRIPTION MC = 16.00% MC= 16.70% SM MC = 13.10% 10 MC = 6.30% MC = 22.50% Brown silty SAND, loose, moist -becomes mottled with iron oxide staining -becomes dense, lighter brown and cemented -increased cobbles -becomes very dense at 10’ 11.0 Brown poorly graded SAND with gravel, loose, moist SP 12.5 ML Brown gray LOAM, medium dense, moist 14.0 Test pit terminated at 14.0 feet below existing grade. No groundwater encountered during excavation. Bottom of test pit at 14.0 feet. GE N E R A L QH ! T P / W E L L 0 B 9 5 . G P J G I N T U S G D T 6 / 1 2 A J 7 V. Earth Solutions NW 2881 152nd Avenue N.E. Redmond, Washington 98052 Telephone: 425-284-3300 Fax: 425-284-2855 CLIENT JCR Development PROJECT NUMBER 0895 DATE STARTED 5/23/07 COMPLETED 5/23/07 EXCAVATION CONTRACTOR NW Excavating EXCAVATION METHOD________________________ LOGGED BY SHA__________________ NOTES DeDth of ToDSoil & Sod 12' CHECKED BY SHA TEST PIT NUMBER TP-2 PAGE 1 OF 1 GROUND ELEVATION ________________ TEST PIT SIZE GROUND WATER LEVELS: AT TIME OF EXCAVATION ^______________________ AT END OF EXCAVATION ^_______________________ AFTER EXCAVATION —__________________________ PROJECT NAME 4518 Talbot Road PROJECT LOCATION Renton, Washington £L LUa LU Q- tK 9=3 TESTS ■CD MC = 15 80% MC = 15.30% SM SP- SM MC = 15.60% MC = 10.90% SM ML 2.5 5.0 7.0 MATERIAL DESCRIPTION Brown silty SAND, loose, moist SILT, medium dense, moist -iron oxide staining Brown gray silty SAND with gravel, dense, moist to wet -cemented Gray SILT with sand, very dense, moist Test pit terminated at 9.0 feet below existing grade. No groundwater en countered during excavation. Bottom of test pit at 9.0 feet. GE N E R A L 8 H / T P l W E L L 0 8 3 S . G P J G 1 N T U S . G D T 6 / 1 2 / 0 7 c—7 Earth Solutions NW 2881 152nd Avenue N,E. Redmond, Washington 98052 Telephone: 425-284-3300 Fax: 425-284-2855 TEST PIT NUMBER TP-3 PAGE 1 OF 1 CLIENT JCR Development PROJECT NAME 4518 Talbot Road PROJECT NUMBER 0895 PROJECT LOCATION Renton, Washington DATE STARTED 5/23/07 COMPLETED 5/23/07 GROUND ELEVATION TEST PIT SIZE EXCAVATION CONTRACTOR NW Excavatina EXCAVATION METHOD GROUND WATER LEVELS: ATTIME OF EXCAVATION — LOGGED BY SHA CHECKED BY SHA AT END OF EXCAVATION — NOTES Depth of Toosoil & Sod 12"AFTER EXCAVATION — Q- <tt LU ~Q UJ Q_ y- lu UJ g |1w TESTS -O <3 MATERIAL DESCRIPTION . 10 15 MC = 7.80% MC = 7.00% MC = 8.90% MC = 3,70% MC = 8.60% SM Brown silty SAND with gravel, loose, moist • « 4.5 Brown gravelly coarse SAND, medium dense, moist GW * -becomes very dense, increased cobbles<* k V V. £ ■c GP- GM GP Cyh ft 9.0 Brown well graded SAND with gravel, medium dense, moist 170 -increasing gravel -increased moisture Brown extremely gravelly SAND, medium dense, moist 1B.0 Test pit terminated at 18.0 feet below existing grade. No groundwater encountered during excavation. Bottom of test pit at 18.0 feet. GE N E R A L 9 H / T P / W E L L 0 3 S S G P J G t N T ' J S G O T 6 / 1 2 / 0 7 i- Earth Solutions NW 2881 152nd Avenue N.E, Redmond, Washington 98052 Telephone: 425-284-3300 Fax: 425-284-2855 TEST PIT NUMBER TP-4 PAGE 1 OF 1 CLIENT JCR Development PROJECT NAME 4518 Talbot Road PROJECT NUMBER 0895 PROJECT LOCATION Renton. Washington DATE STARTED 5/23/07 COMPLETED 5/23/07 GROUND ELEVATION TEST PIT SIZE EXCAVATION CONTRACTOR NW Excavating EXCAVATION METHOD________________________ LOGGED BY SHA___________________ NOTES Depth of Topsoil & Sod 12" CHECKED BY SHA GROUND WATER LEVELS: AT TIME OF EXCAVATION AT END OF EXCAVATION AFTER EXCAVATION — X t a? hi — Q HI CL f- HI Hl«> -ISx=>5 Z < w TESTS -O O MATERIAL DESCRIPTION 10 15 MC = 7.00% MC = 4.60% SM MC = 17.10% MC = 4 60% SM Brown silty SAND, loose, moist -becomes more coarse and clean at 5' 10.5 Brown SAND with silt, medium dense, moist, iron oxide staining in layers, loamy 12.0 Brown poorly graded SAND with gravel, loose, moist SP MC = 5.30%-increasing gravel content 16.0 Test pit terminated at 16.0 feet below existing grade. No groundwater encountered during excavation. Bottom of test pit at 16.0 feet. GE N E R A L B H / T P / W E L L 0 8 9 5 G P J G I N T U S . G D T 6 / 1 2 ) 0 7 ^ji v JEriTrni'rriti: Earth Solutions NW 2881 152nd Avenue N.E. Redmond, Washington 98052 Telephone: 425-234-3300 Fax: 425-284-2855 TEST PIT NUMBER TP-5 PAGE 1 OF 1 CLIENT JCR Development PROJECT NAME 4518 Talbot Road PROJECT NUMBER 0895 PROJECT LOCATION Renton, Washington DATE STARTED 5/23/07 COMPLETED 5/23/07 GROUND ELEVATION TEST PIT SIZE EXCAVATION CONTRACTOR NW Excavating EXCAVATION METHOD _______________________ LOGGED BY SHA CHECKED BY SHA NOTES Depth of Topsoil & Sod 8" GROUND WATER LEVELS: AT TIME OF EXCAVATION AT END OF EXCAVATION — AFTER EXCAVATION — Q.4U 111 D Q. asfeuP z w TESTS O o MATERIAL DESCRIPTION SM MC = 13,60% MC = 12,60% ML Brown silty SAND, loose, moist, iron oxide staining -becomes dense to very dense, increase in rock content 4.0 Brown SILT with sand, very dense, moist to wet 7.5 Test pit terminated at 7.5 feet below existing grade. No groundwater encountered during excavation. Bottom of test pit at 7.5 feet. GE N E R A L B N / T P / W E L L 0 6 9 0 . G P J G 5 N T U & G O T 1 1 / 2 2 / 0 6 gBgmminiT ttTOPW Earth Solutions NW, LLC 2881 152nd Avenue N.E. Redmond, WA 98052 Telephone: 4252843300 Fax: 4252842855 TEST PIT NUMBER TP-1 PAGE 1 OF 1 CLIENT John G. Radovich Development PROJECT NAME Talbot Medical Building PROJECT NUMBER 0690 PROJECT LOCATION Renton, Washington DATE STARTED 11/18/06 COMPLETED 11/18/06 EXCAVATION CONTRACTOR NW Excavating EXCAVATION METHOD_______________________ LOGGED BY SSR CHECKED BY SSR NOTES Depth of Topsoil & Sod 12": forest duff GROUND ELEVATION________________ GROUND WATER LEVELS: AT TIME OF EXCAVATION AT END OF EXCAVATION — AFTER EXCAVATION —________ TEST PIT SIZE Q. fcUJ Q UJ0.>-o: r- UJ m CD a! | izw TESTS ■ O MATERIAL DESCRIPTION SM 10 SM MC = 26.80% MC = 10.70% 4.0 Brown silty SAND, loose, moist to wet -trace organics -trace oxide staining -trace gravel -becomes medium dense Brown silty SAND, dense, moist -becomes very dense 10,0 Test pit terminated at 10.0 feet below existing grade. Groundwater seepage encountered at 2,0 feet during excavation. Bottom of test pit at 10.0 feet. GE N E R A L B H / T F > / W E L L 0 6 9 0 G P J G I N T U S G D T 1 1 / 2 2 / 0 6 uuIJSJTrnTmn,; Earth Solutions NW, LLC 2881 1S2nd Avenue N.E. Redmond, WA 980S2 Telephone: 4252843300 Fax: 4252842855 TEST PIT NUMBER TP-2 PAGE 1 OF 1 CLIENT John C. Radovich Development PROJECT NAME Talbot Medical Building PROJECT NUMBER 0690 PROJECT LOCATION Renton. Washington DATE STARTED 11/18/06 COMPLETED 11/18/06 GROUND ELEVATION TEST PIT SIZE EXCAVATION CONTRACTOR NW Excavating EXCAVATION METHOD ______________________ LOGGED BY SSR_______________CHECKED BY SSR NOTES Depth of Topsoil & Sod 12": forest duff GROUND WATER LEVELS: AT TIME OF EXCAVATION AT END OF EXCAVATION AFTER EXCAVATION -__________ fl. £, Ul wa tua. ujm si TESTS is o MATERIAL DESCRIPTION SM Brown silty SAND, loose, moist to wet 1.5 MC = 12.00% Brown poorly graded SAND with gravel, loose, moist -trace gravel -trace silt -slight caving SP -becomes medium dense 10 11.0 SM MC = 8.80% Tan silty fine SAND, dense, moist 140 Test pit terminated at 14.0 feet below existing grade. No groundwater encountered during excavation. Bottom of test pit at 14.0 feet. GE N E R A L B H / T P / W E L L 0 6 9 0 G P J G I N T U S . 6 D T 1 1 / 2 2 / 0 6 Earth Solutions NW, LLC 2881 152nd Avenue N.E. Redmond, WA 98052 Telephone: 4252843300 Fax: 4252842855 TEST PIT NUMBER TP-3 PAGE 1 OF 1 CLIENT John C, Radovtch Development PROJECT NAME Talbot Medical Building PROJECT NUMBER 0690 PROJECT LOCATION Renton, WashmQton DATE STARTED 11/18/06 COMPLETED 11/18/06 GROUND ELEVATION TEST PIT SIZE EXCAVATION CONTRACTOR NW Excavating EXCAVATION METHOD_______________________ LOGGED BY SSR_______________ GROUND WATER LEVELS: AT TIME OF EXCAVATION - CHECKED BY SSR NOTES Depth of Topsoil & Sod 12”: forest duff AT END OF EXCAVATION — AFTER EXCAVATION — CLUi ^ Q UJ 0.K Hiu LU £ ii<M TESTS no MATERIAL DESCRIPTION 10 SM MC = 17.00% MC = 16.20% SM SM MC = 10.90% Brown silty fine SAND, loose, wet -oxide staining -becomes medium dense 5,5 Brown silty SAND with gravel, dense, moist -occasional small boulders 9.0 Gray silty fine SAND with gravel, very dense, moist mo Test pit terminated at 10.0 feet below existing grade. Groundwater seepage encountered at 2 0 feet during excavation. Bottom of test pit at 10.0 feet. GE N E R A L B H / T P / W E L L 0 6 9 0 G P J G I N T U S G D T 1 1 / 2 2 / 0 6 fw'-jMjijri-1 ^■HUnrmJF W* Earth Solutions NW, LLC 2881 152nd Avenue N.E. Redmond, WA 98052 Telephone: 4252843300 Fax: 4252842855 CLIENT John C. Radovich Development________________________ PROJECT NUMBER 0690 DATE STARTED 11/18/06____________ COMPLETED 11/18/06 EXCAVATION CONTRACTOR NW Excavating____________________ EXCAVATION METHOD______________________________________ LOGGED BY SSR___________________ CHECKED BY SSR NOTES Depth ofTopsoil & Sod 16": forest duff___________________ GROUND ELEVATION________________ TEST PIT SIZE____________________ GROUND WATER LEVELS: AT TIME OF EXCAVATION ^_______________________________________ AT END OF EXCAVATION _________________________________________ AFTER EXCAVATION -____________________________________________ TEST PIT NUMBER TP-4 PAGE 1 OF 1 PROJECT NAME Talbot Medical Building_________________________________ PROJECT LOCATION Renton. Washington CL C LU — □ UJQ.>-ir r- Hi nj CD -j5M05 TESTS 0 MC = 8.90% 5 MC = 10.40% 05d 05d o X f MATERIAL DESCRIPTION io'.-JTPSL - 1.5 SM SM 0.0 9.0 Dark brown TOPSOIL, loose, wet Brown silty fine SAND, loose, moist -trace gravel -oxide staining -becomes dense Brown silty SAND with gravel, dense, moist Test pit terminated at 9.0 feet below existing grade. Groundwater seepage encountered at 2.0 feet during excavation. Bottom of test pit at 9.0 feet. GE N E R A L B H / T P / W E L L 0 6 9 0 G P J G I N T U S G O T 1 1 / 2 2 / 0 6 tagjijM. l Earth Solutions NW, LLC 2881 152nd Avenue N.E. Redmond, WA 98052 Telephone: 4252843300 Fax: 4252842855 TEST PIT NUMBER TP-5 PAGE 1 OF 1 CLIENT John C- Radovich Development______________________ PROJECT NUMBER 0690 DATE STARTED 11/18/06____________ COMPLETED 11/18/06 EXCAVATION CONTRACTOR NW Excavating___________________ EXCAVATION METHOD______________________________________ LOGGED BY SSR___________________ CHECKED BY SSR NOTES Depth of Topsoil & Sod 12": forest duff__________________ PROJECT NAME Talbot Medical Building________________ PROJECT LOCATION Renton. Washington GROUND ELEVATION ________________ TEST PIT SIZE GROUND WATER LEVELS: AT TIME OF EXCAVATION —_____________________ AT END OF EXCAVATION _______________________ AFTER EXCAVATION — Q. C Uia HI a.FCi-UJHim u5 O- D |Z « TESTS o O TPSL. 1.0 SM MC = 9 00% MC= 10.40%8.0 MATERIAL DESCRIPTION Darit brown TOPSOIL, loose, wet Brown silty SAND, loose, moist -becomes medium dense -becomes dense -becomes very dense Test pit terminated at 8.0 feet below existing grade. Groundwater seepage encountered at 2.0 feet during excavation. Bottom of test pit at 8.0 feet. GE N E R A L 8 H / T P / W E L L 0 6 9 0 G P J G I N T U S G O T 1 1 / 2 2 / 0 6 .■ HWimrrnvt Bya' \ Earth Solutions NW, LLC 2881 152nd Avenue N.E. Redmond, WA 98052 Telephone: 4252843300 Fax: 4252842855 TEST PIT NUMBER TP-6 PAGE 1 OF 1 CLIENT John C. Radovich Development________________________ PROJECT NUMBER 0690 DATE STARTED 11/18/06____________ COMPLETED 11/18/06 EXCAVATION CONTRACTOR NW Excavating ___________________ EXCAVATION METHOD______________________________________ LOGGED BY SSR___________________ CHECKED BY SSR NOTES Depth ofTopsoil & Sod 18": forest duff___________________ GROUND ELEVATION________________ TEST PIT SIZE GROUND WATER LEVELS: AT TIME OF EXCAVATION ^_____________________ AT END OF EXCAVATION _______________________ AFTER EXCAVATION —_________________________ PROJECT NAME Talbot Medical Building________________ PROJECT LOCATION Renton, Washington x a*?IN m a 2z TESTS g o TPSLlY'-.it o. J 1.5 MATERIAL DESCRIPTION Dark brown TOPSOIL, loose, wet Brown sandy SILT, loose, wet -oxide staining -trace gravel - 5 MC = 11.00%-becomes dense ML -becomes very dense ■boulder 10 MC = 12.30%11.0 Test pit terminated at 11.0 feet below existing grade. Groundwater seepage encountered at 2.0 feet during excavation. Bottom of test pit at 11.0 feet. Appendix B Laboratory Test Results ES-0895.03 Earth Solutions NW, LLC GR A I N S I Z E E S f l a S G P J G I N I U S L A B G O T 5 / 3 0 / G 7 Earth Solutions NW, LLC 2881 1S2nd Avenue N.E, Redmond, WA 98052 Telephone: (425) 234-3300 Fax: (425) 284-2855 GRAIN SIZE DISTRIBUTION CLIENT JCR Development PROJECT NAME Talbot Road PROJECT NUMBER £3 895 PROJECT LOCATION Renton US SIEVE OPENING IN INCHES I 6 4 3 2 L5 1 3iil 1/23/0 3 U.S, SIEVE NUMBERS [ 810 1416 20 30 40 5 0 60 100140200 HYDROMETER Trf*Tss!!100 95 90 85 80 75 \-i70 55 60 55 50 45 40 35 30 25 20 V10 0.011001 0.1 GRAIN SIZE IN MILLIMETERS 0.001 COBBLES GRAVEL SAND coarse fine coarse medium fine SILT OR CLAY Specimen Identification Classification LL PL PI Cc Cu •TP-01 4.5ft.USDA: Brown sandy loam, USCS: SM X TP-01 11.5ft.USDA: Brown sand, USCS: SP 0.90 2.31 A TP-01 12.5ft.USDA; Olive brown loam, USCS: ML *TP-02 7.5ft.USDA: Gray gravelly loam, USCS: SM ©TP-03 5.0ft.USDA: Brown extremely gravelly coarse sand, USCS: GW 1.02 25.56 Specimen Identification D100 D60 D30 D10 %G ravel %Sand %Silt %Clay •TP-01 4.5ft.19 0.165 4.2 50.0 45.8 X TP-01 11.5ft.4.75 0.54 0.338 0.234 0.0 97.3 2.7 A TP-01 12.5ft.4.75 0.0 29.6 70.4 •k TP-02 7.5ft.37.5 0.189 17.2 39.8 43.0 ©TP-03 5.0ft.37.5 8.496 1.698 0.332 53.5 43.1 3.4 GR A I N S I Z E E S - B 9 5 . G P J G 1 N T U S L A B G D T 5 / 3 0 / 0 7 Earth Solutions NW, LLC 2881 152nd Avenue N.E. Hedmond, WA 98052 Telephone: (425) 284-3300 Fax: (425) 284-2855 GRAIN SIZE DISTRIBUTION CLIENT JCR Development PROJECT NAME Talbot Road PROJECT NUMBER ES-895 PROJECT LOCATION Renton xC3 LU5>-mir LU Litotriu CL U S. SIEVE OPENING IN INCHES I U S SIEVE NUMBERS 6 4 3 2 L5 1 3B 1/23t8 3 4 6 810 14 16 20 30 40 50 60 400 140 2Qg 1 0.1 GRAIN SIZE IN MILLIMETERS COBBLES GRAVEL SAND coarse line coarse medium fine HYDROMETER 100 95 90 85 80 I75 70 55 50 55 fi50 45 V40 35 30 25 20 15 10 0.01100 0.001 SILT OR CLAY Specimen Identification Classification LL PL PI Cc Cu •TP-03 9.0ft.USDA: Brown sand, USCS: GP-GM 1.31 3.71 c TP-03 17.0ft.USDA: Olive brown extremely gravelly sand, USCS: GP 0.25 74.55 i TP-04 11.0ft.USDA: Brown loam, USCS: SM k TP-05 5.0ft.USDA: Brown loam, USCS: ML Specimen Identification D100 D60 D30 D10 %G ravel %Sand %Silt %C!ay •TP-03 9.0ft. 19 0.454 0.27 0.122 2.1 91.0 6.8 E TP-03 17.0ft. 37.5 13.407 0.776 0.18 58.4 37.8 3.8 k TP-04 11.0ft.19 0.152 2.8 49.4 47.8 k TP-05 5.0ft.19 0.127 3.8 45.4 50.8 GR A J N S I Z E E S - 6 9 0 G P J P I N T U S L f t B G D T 1 V 2 U 0 6 Earth Solutions NW, LIC 2881 152nd Avenue N.E. Redmond, WA 98052 Telephone: (425) 284-3300 Fax: (425) 284-2855 GRAIN SIZE DISTRIBUTION CLIENT J.C Radovich Company PROJECT NAME Talbot Medical Building PROJECT NUMBER ES-690 PROJECT LOCATION Renton US. SIEVE OPENING IN INCHES I U.S. SIEVE NUMBERS 8 4 3 2 1.5 1 W V2M 3 4 S B10 1416 20 3Q 40 50 60 HYDROMETER 100 140 200 InH "Hi 100 95 Vi,90 B5 K80 75 70 65 60 55 ';l 50 45 40 35 30 25 20 5 10 0.011001 0.1 GRAIN SIZE IN MILLIMETERS 0.001 COBBLES GRAVEL SAND coarse fine coarse medium fine SILT OR CLAY Specimen Identification Classification LL PL PI Cc Cu •TP-01 8.0ft Brown silty SAND, SM SI TP-02 3.0ft.Brown poorly graded SAND with gravel, SP 0.65 6.06 A TP-04 4.0ft Brown silty SAND, SM *TP-06 4.0ft.Light brown sandy SILT, ML Specimen Identification D100 D60 D30 D10 %Gravel %Sand %Silt %Clay •TP-01 8.0ft.19 0.16 3.4 50.0 46.6 a TP-02 3.0ft 19 1.141 0.374 0.188 15.3 82.7 1.9 ▲TP-04 4.0ft.37.5 0.17 11.8 41.6 46.6 ★TP-06 4.0ft.9.5 0.084 2.4 39.3 58.3 Report Distribution ES-0893.03 EMAIL ONLY RJ Development, LLC 401 Central Street Southeast Olympia, Washington 98501 Attention: Mr. Kyle Oster Earth Solutions NW, LLC