Loading...
The URL can be used to link to this page
Your browser does not support the video tag.
Revised Geotech Report recd 6-9-17.pdf
�d ; Geotechnical Engineering Geology Environmental Scientists Construction Monitoring AP p �wN i ,'�lyror w, ra� a� �„� /� qr,,. mrriM'i•�9' w � / '� / If w4 M /Jk REVISED A4 PROPOSED GEOTECHNICAL ENGINEERING STUDYx 4� �n F ROPO SED SII GLE-FAMILY RESIDENCES 612 — 7th AVENUE SOUTH EDMONDS, WASHINGTON; 7.0 / PREPARED FOR SELECT HOMES, INC. December 29, 2016 Revised June 6, 2017 a . L AOA-4 4.� S38 3 Henry T. Wright, P.E. Senior Project Engineer Raymond A. Coglas, P.E. Principal REVISED GEOTECHNICAL ENGINEERING STUDY PROPOSED SINGLE-FAMILY RESIDENCES 612-7 TH AVENUE SOUTH EDMONDS, WASHINGTON ES -4937.01 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 Ueolechn"Ical Eflglfleeplflg� Report 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 solelyfor the 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 —noteven 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 Foci ort Is Based on A Unique Set of roject-Rpeci 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 reportwhose 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 Gootechnical 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 timeto 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 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 gwonviron. mentalstudy differ significantly from those used to perform a geotechnical study. For that reason, a geotechnical engineering report does not usually relate any geoenviron mental 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 -tris 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 he sufficient to prevent mold from growing in or on the structure involved. Iter on Your ASFE-Member Geotecimicial g neer 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. ASFe the sell People an forth 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, tnc. 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 perrnfsstort, Excerpting, guoring, 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 bowie revleit Only members of ASFE may use 1W 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. 1IGER06045,OM December 29, 2016 Revised June 6, 2017 ES -4937.01 Select Homes, Inc. 16531 -13th Avenue West, A-107 Lynnwood, Washington 98037 Attention: Ms. Kayla Clark Dear Ms. Clark: Earth Solutions NW:«. Earth Solutions NW LLC • Geotechnical Engineering • Construction Monitoring • Environmental Sciences Earth Solutions NW, LLC (ESNW) is pleased to present this report titled "Revised Geotechnical Engineering Study, Proposed Single -Family Residences, 612 — 7th Avenue South, Edmonds, Washington". This report was revised to reference current plans and to incorporate additional slope stability analysis. Based on the results of our study, construction of the proposed single- family residential structures at the subject site is feasible from a geotechnical standpoint. Based on the results of our study, the proposed residential structures can be supported on a conventional foundation system bearing on competent native soil, recompacted native soil, or structural fill. Competent soils suitable for support of foundations should be encountered at a depth of roughly three feet below existing grades across the majority of the site; foundations should be advanced deeper, as necessary, to maintain a minimum building setback of 15 feet from the sloped area to the west and northwest of the site and at least a 1 H:1 V setback from the rockery/wall to the north of the site. Slab -on -grade floors should be supported on dense native soil, re -compacted native soil, or structural fill. Where loose, organic or other unsuitable materials are encountered at or below the footing subgrade elevation, the material should be removed and replaced with structural fill, as necessary. This report provides a geologically hazardous areas assessment, and recommendations for foundation subgrade preparation, foundation and retaining wall design parameters, drainage, the suitability of the on-site soils for use as structural fill, and other geotechnical recommendations. The opportunity to be of service to you is appreciated. If you have any questions regarding the content of this geotechnical engineering study, please call. Sincerely, EARTH SOLUTIONS NW, LLC Henry T. Wright, P.E. Senior Project Engineer 1805 - 136th Place N.E., Suite 201 0 Bellevue, WA 98005 0 (425) 449-4704 • FAX (425) 449-4711 Table of Contents ES -4937.01 PAGE INTRODUCTION . ........_ ..... .................... ....., .,..... 1 Proiect Descrilation SITE CONDITIONS...................................................................... 2 Surface............................................................................ 2 Subsurface... .................................. . ....... .... M ..................... 2 Geologic Setting, .......... ........... ............. ........ 3 Groundwater..................................................................... 3 GEOLOGICAL HAZARDS ASSESSMENT ....................................... 3 Slooe Reconnaissance. ..... ............ ....... .......... _... 3 Landslide Hazard Areas Specia,l Study and«« :« BuildingDevelopment Standards .. 7 MinimuM Setback• DISCUSSION AND RECOMMENDATIONS ...................................... 9 General.............................................................................. 9 Site Preparation and Earthwork .............. ___ ............ _........ 10 Temporary Erosion Control......... .................................... 10 In -Situ Soils........................................................................ 10 Structural Fill................................................................. 11 Excavations and Slopes ..................................................... 11 Foundations......................... w .,..................................., ... 11 Seismic Considerations ........ ................. ............. .................. 12 Slab -on -Grade Floors........................................................ 12 Retaining Walls................................................................ 12 (drainage ....... .... ____ ............... ........ ......... ..,.....,, ........... 13 Infiltration Evaluation .............................................. 14 LowImpact Development...,... _ . ........................... 14 Utilily Trench Support and Backfill ...................................... 16 PavementSections........................................................... 16 LIMITATIONS.. . .............................. . ....... ... , ................. 16 Additional Services... ....... ..................................... .... ...I ... 1 16 Earth Solutions NW, LLC Table of Contents Continued ES -4937.01 GRAPHICS Plate 1 Vicinity Map Plate 2 Test Pit Location Plan Plate 3 Foundations Adjacent to Slopes Plate 4 Retaining Wall Drainage Detail Plate 5 Footing Drain Detail APPENDICES Appendix A Subsurface Exploration Test Pit Logs Appendix B Laboratory Test Results Grain Size Distribution Appendix C Slope Stability Analysis Results Earth Solutions NW, LLC REVISED GEOTECHNICAL ENGINEERING STUDY PROPOSED SINGLE-FAMILY RESIDENCES 612-7 TH AVENUE SOUTH EDMONDS, WASHINGTON ES -4937.01 INTRODUCTION General This geotechnical engineering study was prepared for the proposed single-family residential structures to be constructed at 612 — 7th Avenue South in Edmond's, Washington. To complete the scope of services detailed in our proposal PES -4937 dated November 21, 2016, we performed the following: « Subsurface exploration and characterization of soil and groundwater conditions by way of test pits excavated at accessible areas of the site; a• Laboratory testing of soil samples obtained during subsurface exploration; • Engineering analyses and recommendations for the proposed development, and; • Preparation of this report. The following documents and/or resources were reviewed as part of our report preparation; +• Boundary and Topography Survey, prepared by Lovell-Sauerland & Associates, Inc., dated November 10, 2016; • Preliminary Plans, prepared by RAM Engineering, Inc., dated February 14, 2017; • Geologic Map of the Edmonds East and Part of the Edmonds West Quadrangle, Washington, prepared by James P. Minard, dated 1983; • North Edmonds Earth Subsidence and Landslide Hazard Area Summary Report, prepared by Landau Associates, dated March 14, 2007; • Department of Ecology Stormwater Management Manual for Western Washington, Volume III Hydrologic Analysis and Flow Control BMPs, dated August 2012 • Edmonds City Code, Chapter 23.80 (Geologically Hazardous Areas), and; • Online Web Soil Survey (WSS) resource provided by United States Department of Agriculture (USDA), Natural Resources Conservation Services. Earth Solutions NW, LLC Select Homes, Inc. December 29, 2016 Revised June 6, 2017 Pro'ect Description ES -4937.01 Page 2 Based on the site plan provided to us, the existing single-family residential structure will be demolished and two new single-family residential structures will be constructed. We anticipate grading activities will primarily include cuts to establish the planned building alignments. Based on the existing grades, we estimate cuts to establish building pad and foundation subgrade elevations will be on the order of up to four to six feet; we understand grading for the proposed houses will reduce the elevations adjacent to the sloped areas. However, grading plans were not available at the time this report was prepared. Site improvements will also include underground utility installations. At the time this report was prepared, specific building load values were not available. However, we anticipate the proposed residential structures will consist of relatively lightly loaded wood framing supported on conventional foundations. Based on our experience with similar developments, we estimate wall loads on the order of two kips per linear foot and slab -on -grade loading of 150 pounds per square foot (psf). If the above design assumptions are incorrect or change, ESNW should be contacted to review the recommendations in this report. ESNW should review the final design to verify the geotechnical recommendations provided in this report have been incorporated into the plans. SITE CONDITIONS Surface The subject site located at 612 - 7th Avenue South in Edmonds, Washington, as illustrated on the Vicinity Map (Plate 1). The site consists of one residential tax parcel (Snohomish County parcel number 27032500203500) totaling approximately 0.41 acres of land area. The property is currently developed with a single-family residence and associated improvements. The majority of the site is relatively level with a gentle west descending slope. Based on site observation and available topographic data, a west descending slope with a gradient in excess of 55 percent and elevation change of up to 14 feet is located to the west of the site. Vegetation within the steep slope area consists of saplings and ivy groundcover. The subject site is bordered to the north, south, and west by residential structures and to the east by 7th Avenue South. The Test Pit Location Plan (Plate 2) illustrates the approximate limits and local topography of the property. Subsurface As part of the subsurface exploration, two test pits were excavated in the north-west and north- east corners of the site for purposes of assessing soil and groundwater conditions. The test pits were advanced to depths of approximately nine feet below existing grade. Please refer to the test pit logs provided in Appendix A for a more detailed description of the subsurface conditions. Soil conditions observed at test pit locations consisted of loose to medium dense poorly graded sand (Unified Soil Classification System: SP) outwash deposits. Overall soil relative density increased with depth. Earth solutions NW, LLC Select Homes, Inc. December 29, 2016 Revised June 6, 2017 Geologic Setting ES -4937.01 Page 3 According to the referenced geologic map, the subject site is underlain by outwash (Qva) deposits. Soil conditions observed at the test pit locations were generally consistent with outwash deposits. According to the referenced NRCS soil survey, the subject site consists of Alderwood/Everett series soils. Groundwater No groundwater seepage was observed during our fieldwork on December 2, 2016. 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. GEOLOGICAL HAZARDS ASSESSMENT As part of this geotechnical engineering study, the referenced chapter of the Edmonds City Code (ECC) was reviewed. Per the ECC requirements, the following topics related to development plans and site conditions are addressed. ` During our fieldwork, we performed a visual slope reconnaissance across the steep slope areas to the west and northwest of the site as well as the slope and rockery/wall area to the north of the site. The main focus of our reconnaissance was to identify signs of instability or erosion hazards along the site slopes. The typical instability indicators include features such as head scarps, tension cracks, hummocky terrain, groundwater seeps along the surface and erosion features such as gulleys and rills. During the slope reconnaissance, no signs of recent, large scale erosion or slope instability were observed. The slope is vegetated with saplings and ivy groundcover. In general, based on the slope reconnaissance, stability of the sloped areas adjacent to the property can be characterized as good. Additionally, indications of previous grading and slope modification were observed across the sloped areas such as existing walls, utilities, and landscape paver steps.- Erosion teps: Erosion Hazard Areas — ECC 23.80.020.A. With respect to erosion hazard areas, section 23.80.020 of the ECC defines erosion hazards as "at least those areas identified by the U.S. Department of Agriculture's Natural Resources Conservation Service as having a "moderate to severe", "severe", or "very severe" rill and inter - rill erosion hazard. Erosion hazard areas are also those areas impacted by shoreland and/or stream bank erosion. Within the city of Edmonds, erosion hazard areas include: Earth Solutions NW, LLC Select Homes, Inc. December 29, 2016 Revised June 6, 2017 ES -4937.01 Page 4 Those areas of the city of Edmonds containing soils that may experience severe to very severe erosion hazard. This group of soils includes, but is not limited to, the following when they occur on slopes of 15 percent or greater: a. Alderwood soils (15 to 25 percent slopes); b. Alderwood/Everett series (25 to 70 percent slopes); c. Everett series (15 to 25 percent slopes); 2. Coastal and stream erosion areas which are subject to the impacts from lateral erosion related to moving water such as stream channel migration and shoreline retreat; 3. Any area with slopes of 15 percent or greater and impermeable soils interbedded with granular soils and springs or ground water seepage; and 4. Areas with significant visible evidence of ground water seepage, and which also include existing landslide deposits regardless of slope. The on-site soils are generally consistent with Alderwood/Everett series soils. Based on the ECC definition, the steep slope areas adjacent to the property classify as erosion hazard areas. Typical BMP measures and implementation are expected to be sufficient for adequately managing and mitigating the erosion potential for this project. Landslide Hazard Areas — ECC 23.80.020.13. With respect to landslide hazard areas, section 23.80.020 of the ECC defines landslide hazard areas as "areas potentially subject to landslides based on a combination of geologic, topographic, and hydrologic factors. They include areas susceptible because of any combination of soil, slope (gradient), slope aspect, structure, hydrology, or other factors. Within the city of Edmonds, landslide hazard areas specifically include: 1. Areas of ancient or historic failures in Edmonds which include all areas within the earth subsidence and landslide hazard area as identified in the 1979 report of Robert Lowe Associates and amended by the 1985 report of GeoEngineers, Inc., and further discussed in the 2007 report by Landau Associates; 2. Coastal areas mapped as class U (unstable), UOS (unstable old slides) and URS (unstable recent slides) in the Department of Ecology Washington coastal atlas; 3. Areas designated as quaternary slumps, earthflows, mudflows, or landslides on maps published by the United States Geological Survey or Washington State Department of Natural Resources; 4. Any slope of 40 percent or steeper that exceeds a vertical height of 10 feet over a 25 - foot horizontal run. Except for rockeries that have been engineered and approved by the engineer as having been built according to the engineered design, all other modified slopes (including slopes where there are breaks in slopes) meeting overall average steepness and height criteria should be considered potential landslide hazard areas; 5. Any slope with all three of the following characteristics: a. Slopes steeper than 15 percent; b. Hillsides interesting geologic contacts with relatively permeable sediment overlying a relatively impermeable sediment; and c. Springs or ground water seepage; Earth Solutions NW, LLC Select Homes, Inc. December 29, 2016 Revised June 6, 2017 ES -4937.01 Page 5 6. Any area potentially unstable as a result of rapid stream incision or stream bank erosion 7. Any area located on an alluvial fan, presently subject to, or potentially subject to, inundation by debris flow or deposition of stream -transported sediments, and; 8. Any slopes that have been modified by past development activity that still meet the slope criteria. Based on site observation and the referenced topographic survey, a west -descending steep slope with gradient in excess of 40 percent is located to the west and continues to the northwest of the subject property and a rockery/wall with a slope above is located to the north of the property; as discussed above, indications of previous grading and slope modification were observed across the slopes. Per the above definition of landslide hazard areas, the steep slope to the west and northwest of the subject property classifies as a potential landslide hazard area based on a slope gradient of 40 percent or steeper with a vertical relief of 10 feet or more. The rockery/wall with slope above to the north of the site should not be considered a landslide hazard area due to the engineered rockery/wall which accounts for approximately half of the slope height. The overall stability of the site can be characterized as good and it is our opinion that the potential landslide hazard for the slope to the west and northwest of the site can be considered very low. Additionally, we understand grading for the proposed development will likely include lowering elevations at the top of the sloped areas, effectively reducing the height of the slope to below 10 feet. Mapplin,, of Geologically Hazardous Areas — ECC 23.80.030 Review of available geologically hazardous areas mapping did not reveal any geologically hazardous areas within or immediately adjacent to the subject site. L0=11 K*41111u A. This geotechnical engineering study and geological hazards assessment was completed by a professional engineer licensed in the state of Washington with experience analyzing geologic hazards throughout the Puget Sound region. B. 1. The project area includes the subject site as delineated in the referenced preliminary plans. 2. Erosion hazard areas, as defined above, are located along and adjacent to the north and west site margins. Landslide hazard areas, as defined above, are located to the west and continuing to the northwest of the site. C. This geological hazards assessment included a field investigation and an assessment of geologic hazards. This Geotechnical report has been prepared, stamped, and signed by a qualified professional. 1. It is our opinion the level of analysis completed for this geological hazards assessment is appropriate for the scale and scope of the project and scale of the geological hazard areas present. 2. A discussion of all geologically hazardous areas on the site and any geologically hazardous areas off site potentially impacted by the proposed project is provided in this report. Earth Solutions NW, LLC Select Homes, Inc. December 29, 2016 Revised June 6, 2017 ES -4937.01 Page 6 3. Based on the results of our analysis, the proposed project will not decrease slope stability or pose an unreasonable threat to persons or property either on or off site. These conclusions are based on slope stability analysis completed for representative slope cross-sections as well as the fact the proposed project will reduce height of slopes and loading on the slopes. 4. This geological hazards assessment is provided as adequate information to comply with requirements of ECC geological hazards. 5. This geotechnical report generally follows the guidelines set forth in the Washington State Department of Licensing Guidelines for Preparing Engineering Geology Reports in Washington (2006). 6. Landslide hazard minimum building setback and erosion hazard mitigation recommendations are provided in this report. D. We are not aware of a previous study completed for the subject site. E. The mitigation recommendations include permanent solutions, such as reducing overall height of slopes, building foundation setbacks, and erosion control recommendations. F. This geological hazards assessment and geotechnical engineering study should be reviewed as part of the overall submittal package. 1. Please refer to preliminary plans prepared by RAM Engineering, Inc. for the site plan. a. The height of the slopes and slope gradients are discussed in this report and displayed within the preliminary plans. Representative cross-sections of the slopes to the north and west of the site are displayed within our slope stability analysis results. b. Springs, seeps, or other surface expressions of groundwater were not observed on or within 200 feet of the project area. c. No surface water runoff features were observed during out site visits. 2. a. Vegetative cover across the landslide hazard areas generally consists of non- native groundcover (i.e. ivy), shrubs, and small trees. b. Subsurface conditions are described in the Subsurface section of this report. c. Surface and groundwater conditions are discussed in previous sections of this report. Clear indications of fill were not observed within the test pits excavated at the subject site. However, based on existing retaining walls, rockeries, other improvements, and the flat lots with slopes between, it is evident that some degree of land modification has occurred within and adjacent to the landslide hazard areas. The landslide hazard areas were likely artificially steepened by a combination of cuts and fills completed during historic lot development grading activities. Local natural topography was likely more of a gradual consistent slope. d. The slopes within and adjacent to the subject site generally exhibit good overall stability. A quantitative slope stability analysis was completed as part of this geological hazards assessment; the results of the slope stability analysis are discussed below. e. The slopes within and adjacent to the subject site are not characterized as bluffs and we do not anticipate a retreat of the slopes to occur. f. Based on the sand soils present on the site and no indications of groundwater, we would anticipate the run -out hazard of landslide debris to be confined to a distance of up to half the height of slope away from the toe. If such a landslide occurred, impacts of run -out on downslope properties would likely consist of a few feet of landslide Earth Solutions NW, LLC Select Homes, Inc. December 29, 2016 Revised June 6, 2017 ES -4937.01 Page 7 debris covering the ground adjacent to the toe of the slope. Repair of the slide would likely require cleanup of debris and engineered reconstruction of the slope and/or construction of an engineered retaining wall at the toe of the slope. It should be noted, based on the results of our study, likelihood of such a landslide event occurring adjacent to the subject site is very low and the proposed project will not increase the likelihood. g. A quantitative slope stability analysis was completed as part of this geological hazards assessment; the results of the slope stability analysis are discussed below. h. Recommendations for building siting limitations are provided in this report. i. Proposed surface and subsurface drainage includes collecting surface water from impermeable surfaces and directing them to infiltration systems located along the eastern side of the site. The proposed drainage design is engineered and located in a manner which utilizes the native sand soils and minimizes impacts to sloped areas. The site soils are susceptible to erosion if exposed to surface water runoff without the implementation of BMP measures. However, typical temporary and permanent BMP measures will effectively mitigate the erosion potential. 3. This geotechnical engineering study was prepared by a licensed engineer. a. Geotechnical design parameters are provided within this report. b. Drainage and subdrainage recommendations are provided within this report. c. Earthwork recommendations are provided within this report. d. Recommendations for mitigation of adverse site conditions are provided within this report, as necessary. 4. A preliminary TESC plan is provided as part of the referenced plan package. G. It is our opinion the site erosion hazard areas should be considered stable. H. Based on the results of our study, the site does not contain any seismic hazard areas. Development Standards General Re uirements — ECC 23.80.060 Based on the results of our geological hazards assessment, the proposed project will not increase the threat of the geological hazard to adjacent properties beyond predevelopment conditions, the proposed project will not adversely impact other critical areas, the proposed project is designed so that the hazard to the project is eliminated or mitigated to a level equal to or less than predevelopment conditions, and the project is certified as safe as designed under anticipated conditions. A. 1. We recommend a minimum building setback of 15 feet from the sloped area to the west and northwest of the site and at least a 1 H: 1V setback from the rockery/wall to the north of the site to not increase loading at the top of the slope and rockery/wall. The setback should be measured horizontally from the edge of the footing to the face of the slope and can be established by advancing the foundations deeper; see Plate 3 (Foundation Adjacent to Slope) for an illustration of advancing foundations deeper to achieve the minimum setback. This minimum setback will ensure the buildings do not increase the loading on the slope and rockery/wall. Earth Solutions NW, LLC Select Homes, Inc. December 29, 2016 Revised June 6, 2017 ES -4937.01 Page 8 2. Based on the results of our study, it is our opinion that a buffer is not necessary for the landslide hazard areas. The proposed project will include reducing the overall height .of the landslide hazard areas. 3. The proposed project will include removing some soil at the top of landslide hazard areas, effectively reducing the overall height and loading of the landslide hazard areas. The alteration will include establishing permanent erosion control and drainage measures at the top of the landslide and erosion hazard areas. Provided the recommendations in this report and subsequent geotechnical recommendations are incorporated into the design and construction of the project, the proposed alteration will not increase surface water discharge or sedimentation to adjacent properties beyond predevelopment conditions, will not decrease slope stability on adjacent properties, and such alterations will not adversely impact other critical areas. 4. a. As part of this geological hazards assessment, we completed slope stability analysis of the landslide hazard area located along the west side of the property and the rockery/wall with slope to the north side of the property; the full results of the slope stability analysis are included in Appendix C of this report. The cross- sections are representative of approximate slope and structure configurations; the cross-section locations are illustrated on the Test Pit Location Plan (Plate 2). The following table provides a summary of the safety factor (SF) results: Cross -Section Static SF Seismic SF A -A 2.1 1.2 B -B 1.7 1.2 The above results indicate compliance with ECC 23.80.070.A.4.a. b. It is our opinion that the structures and improvements have been located and engineered in a manner which sufficiently mitigates impacts to geologically hazardous areas. C. Historic development of the subject property and adjacent properties previously altered the natural contour of the slopes. The proposed project will reduce the overall height of the slopes and foundations will be advanced deeper, as necessary, to minimize impacts to the slopes. d. The structures and improvements have been located and engineered in a manner that minimizes impacts to the most critical portions of the site by locating the structures along the east side of the property. e. The proposed development will not result in greater risk or a need for increased buffers on neighboring properties. f. Foundation retaining walls will be utilized, as necessary, to achieve landslide hazard setbacks. 5. We did not observe any vegetation within the subject site which should be retained to maintain site and slope stability. 6. It is our opinion that this site should not be restricted to seasonal clearing and grading work. This opinion is based on the relatively small scope of the project and relatively small scale of the geological hazard areas. 7. We are not aware of proposed point discharges. Earth Solutions NW, LLC Select Homes, Inc. December 29, 2016 Revised June 6, 2017 ES -4937.01 Page 9 The proposed development will involve demolition of the existing single-family residential structure and construction of two new single-family residential structures. Based on the referenced site plans, the grading will involve cuts and fills to establish level building pad areas; we understand grading for the proposed development will likely include lowering elevations at the top of the sloped areas. It is our opinion the proposed project will not decrease slope stability or pose an unreasonable threat to persons or property either on or off site. These determinations are based on the relatively small extent of the previously modified steeply sloped areas, stable nature of the site soils, the relatively minor grading proposed which will reduce the overall height of the slope, and overall minor scale and scope of the proposed project. Minimum Building Setback We recommend a minimum building setback of 15 feet from the sloped area to the west and northwest of the site and at least a 1 H:1V setback from the rockery/wall to the north of the site to not increase loading at the top of the slope and rockery/wall. The setback should be measured horizontally from the edge of the footing to the face of the slope and can be established by advancing the foundations deeper; see Plate 3 (Foundation Adjacent to Slope) for an illustration of advancing foundation deeper to achieve the minimum setback. This minimum setback will ensure the buildings do not increase the loading on the slope and rockery/wall. DISCUSSION AND RECOMMENDATIONS General Based on the results of our study, in our opinion, construction of the proposed residential structures at the subject' site is feasible from a geotechnical standpoint. The primary geotechnical considerations associated with the proposed development include foundation support, temporary excavations, retaining walls, and the suitability of the on-site soils for use as structural fill. Based on the results of our study, the proposed residential structures can be supported on a conventional foundation system bearing on competent native soil, recompacted native soil, or structural fill. Competent soils suitable for support of foundations should be encountered at a depth of roughly three feet below existing grades across the majority of the site; foundations should be advanced deeper, as necessary, to maintain a minimum building setback of 15 feet from the sloped area to the west of the site and at least a 1 H:1 V setback from the rockery/wall to the north of the site. Slab -on -grade floors should be supported on dense native soil, re - compacted native soil, or structural fill. Where loose, organic or other unsuitable materials are encountered at or below the footing subgrade elevation, the material should be removed and replaced with structural fill, as necessary. Earth Solutions NW, LLC Select Homes, Inc. December 29, 2016 Revised June 6, 2017 ES -4937.01 Page 10 This study has been prepared for the exclusive use of Select Homes, Inc. 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. Based on the referenced site plans and given the existing topography, we anticipate grading for the project will involve cuts of up to three to five feet to establish building pad and foundation subgrade alignments. Silt fencing and temporary erosion control measures should be placed along the perimeter of the site prior to beginning grading activities. Temporary Erosion Control Temporary construction entrances, consisting of at least six inches of quarry spalls can be considered in order to minimize off-site soil tracking and to provide a temporary road surface. Silt fences should be placed along the margins of the property. Interceptor swales and a temporary sediment pond may be necessary for control of surface water during construction. Erosion control measures should conform to the Washington State Department of Ecology (DOE) and City of Edmonds standards. In -Situ Soils From a geotechnical standpoint, the soils encountered at the test pit locations are generally suitable for use as structural fill. However, successful use of the on-site soils will largely be dictated by the moisture content of the soils at the time of placement and compaction. The site soils were generally in a damp to moist condition at the time of the exploration on December 2, 2016. Based on the conditions encountered during our fieldwork, the site soils will generally have a moderate sensitivity to moisture. During periods of dry weather, the on-site soils should generally be suitable for use as structural fill, provided the moisture content is at or near the optimum level at the time of placement. Successful placement and compaction of the on-site soils during periods of precipitation will be difficult. If the on-site soils cannot be successfully compacted, the use of an imported soil may be necessary. Imported soil intended for use as structural fill should consist of a well -graded granular soil with a moisture content that is at or near 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 defined as the percent passing the Number 200 sieve, based on the minus three-quarter inch fraction. Earth Solutions NW, LLC Select Homes, Inc. December 29, 2016 Revised June 6, 2017 Structural Fill ES -4937.01 Page 11 Structural fill is defined as compacted soil placed in foundation, slab -on -grade, and roadway areas. Fills placed to construct permanent slopes and throughout retaining wall and utility trench backfill areas are also considered structural fill. Soils placed in structural areas should be placed in loose lifts of 12 inches or less and compacted to a relative compaction of 90 percent, based on the laboratory maximum dry density as determined by the Modified Proctor Method (ASTM D-1557). For soil placed in utility trenches underlying structural areas, compaction requirements are dictated by the local city, county, or utility district, and in general are specified as 95 percent relative compaction. The upper 24 inches of foundation subgrade areas and the upper 12 inches of slab -on -grade and pavement subgrade areas should be compacted to a relative compaction of at least 95 percent. The Federal Occupation Safety and Health Administration (OSHA) and the Washington Industrial Safety and Health Act (WISHA) provide soil classification in terms of temporary slope inclinations. The loose to medium dense native soils encountered in the upper approximately three to five feet of the test pit locations and where fill and/or groundwater seepage is exposed are classified as Type C by OSHANVISHA. Temporary slopes over four feet in height in Type C soils must be sloped no steeper than 1.5H:1V (Horizontal:Vertical). Medium dense to dense native soils encountered below approximately three to five feet where no groundwater seepage is exposed would be classified as Type B by OSHANVISHA. Temporary slopes over four feet in height in Type B soils must be sloped no steeper than 1H:1V. The presence of perched groundwater may cause caving of the temporary slopes due to hydrostatic pressure. ESNW should observe site excavations to confirm the soil type and allowable slope inclination are appropriate for the soil exposed by the excavation. If the recommended temporary slope inclination cannot be achieved, temporary shoring may be necessary to support excavations. Permanent slopes should maintain a gradient of 2H:1V, or flatter, and should be planted with vegetation to enhance stability and to minimize erosion. A representative of ESNW 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, as necessary. Foundations The proposed residential structures can be supported on a conventional foundation system bearing on competent native soil, recompacted native soil, or structural fill. Competent soils suitable for support of foundations should be encountered at a depth of roughly three feet below existing grades across the majority of the site; foundations should be advanced deeper, as necessary, to maintain a minimum building setback of 15 feet from the sloped area to the west and northwest of the site and at least a 1 H: 1V setback from the rockery/wall to the north of the site. Slab -on -grade floors should be supported on dense native soil, re -compacted native soil, or structural fill. Where loose, organic or other unsuitable materials are encountered at or below the footing subgrade elevation, the material should be removed and replaced with structural fill, as necessary. Earth Solutions NK LLC Select Homes, Inc. December 29, 2016 Revised June 6, 2017 ES -4937.01 Page 12 Provided the structures will be supported as described above, the following parameters can be used for design of the new foundations: o Allowable soil bearing capacity 2,500 psf 0 Passive earth pressure 300 pcf (equivalent fluid) o Coefficient of friction 0.40 A one-third increase in the allowable soil bearing capacity can be assumed for short-term wind and seismic loading conditions. With structural loading as expected, total settlement in the range of one inch is anticipated, with differential settlement of about one-half inch. The majority of the settlements should occur during construction, as dead loads are applied. Seismic Considerations The 2015 IBC recognizes ASCE for seismic site class definitions. If the project will be permitted under the 2015 IBC, in accordance with Table 20.3-1 of ASCE, Minimum Design Loads for Buildings and Other Structures, Site Class D', should be used for design. In our opinion, the site is not susceptible to liquefaction. The soil relative density and the absence of an established shallow groundwater table are the primary bases for this opinion. Slab -On -Grade Floors Slab -on -grade floors should be supported on a firm and unyielding subgrade consisting of competent native soil or at least 12 inches 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 defined as the percent passing the Number 200 sieve, based on the minus three-quarters inch fraction. In areas where slab moisture is undesirable, installation of a vapor barrier below the slab should be considered. If used, the vapor barrier should consist of a material specifically designed to function as a vapor barrier and should be installed in accordance with the manufacturer's specifications. If retaining walls will be utilized, they should be designed to resist earth pressures and applicable surcharge loads. The following parameters can be used for retaining wall design: Earth Solutions NW, LLC Select Homes, Inc. December 29, 2016 Revised June 6, 2017 • Active earth pressure (yielding condition) • At -rest earth pressure (restrained condition) o Traffic surcharge (passenger vehicles) Passive earth pressure Coefficient of friction Seismic surcharge *Where H equals retained height ES -4937.01 Page 13 35 pcf 50 pcf 70 psf (rectangular distribution) 300 pcf 0.40 6H* Where sloping or other surcharge conditions will be present, supplement recommendations and design earth pressure values should be provided by ESNW. 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. 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 one foot of the wall backfill can consist of a less permeable soil, if desired. A perforated drain pipe should be placed along the base of the wall, and should be connected to an approved discharge location. A typical retaining wall drainage detail is provided as Plate 4. �r e» No groundwater seepage was observed during our fieldwork on December 2, 2016. Water seepage is possible in site excavations, particularly in the winter, spring and early summer months. Temporary measures to control groundwater seepage and surface water runoff during construction will likely involve passive elements such as interceptor trenches and sumps, as necessary. Surface water should not be allowed to runoff over sloped areas and should not be allowed to pond near the top of sloped areas or retaining structures. Surface grades must be designed to direct water away from buildings. The grade adjacent to buildings should be sloped away from the buildings at a gradient of at least 2 percent for a horizontal distance of ten feet. In our opinion, perimeter footing drains should be installed at or below the invert of the building footings. A typical footing drain detail is provided on Plate 5 of this report. Earth Solutlons NW, LLC Select Homes, Inc. December 29, 2016 Revised June 6, 2017 Infiltration Evaluation ES -4937.01 Page 14 We understand drywells, trenches or other methods will be utilized for on-site infiltration. For design, the long term infiltration rate was evaluated based on the criteria specified in the referenced 2012 DOE Manual (Section 3.3.4). Section 3.3.4 of the referenced DOE Manual provides criteria for estimating the long term infiltration rate based on soil grain size analysis method and USDA soil classification. Based on the sieve analysis data from soil samples collected at test pit locations TP -1 and TP -2 (representative locations for proposed infiltration systems) the soils are classified as slightly gravelly sand to very gravelly coarse sand. Given the sieve analysis testing and observation of soil conditions by the undersigned during the field exploration, the criteria specified in Section 3.3.4 of the referenced DOE Manual is an acceptable method for deriving a long term infiltration rate. The following long term infiltration rate was calculated using the following equation and correction factors: Loglo (Ksat) _ -1.57 + 1.90Dlo + 0.015D60 - 0.013D90 - 2.08fr;nes Site variability; number of locations tested • Test Method o Degree of influent control to prevent siltation 9 Total correction factor Calculated Long Term Infiltration Rate* CF„ = 0.33 CFt = 0.40 CFm = 0.90 CFT = 0.119 TP -1 (4') 8.73 in/hr TP -2 (3') 8.46 in/hr TP -2 (8.6') 12.93 in/hr "Per Stormwater Management Manual for Western Washington, August, 2012. Chapter 3.3.4 Due to the proximity to the landslide hazard area, we recommend the long term design infiltration rate to be reduced by one-half. Therefore, we recommend a long term design infiltration rate of 4.0 inches per hour. In addition, we recommend the proposed infiltration systems be located with a setback of at least 25 feet from the top of landslide hazard areas to the west of the subject site. The geotechnical engineer should observe the excavations for the proposed infiltration systems to confirm soil conditions at the time of construction. We recommend an emergency overflow provision be included in the infiltration system design. Low Impact Development The following table provides our evaluation and recommendations regarding low impact development BMPs for the proposed project: Earth Solutions NK LLC Select Homes, Inc. December 29, 2016 Revised June 6, 2017 ES -4937.01 Page 15 Earth Solutions NW, LLC T5.13: Post -construction soil quality and depth Considered infeasible on slopes of 33 Yes (Volume V, Chapter 5) percent or greater. Roofs l/ / /, f/; // ; / ; / , T5.30: Full dispersion is not T5.30: Full dispersion (Volume V, Chapter 5) No recommended due to sloped topography on-site and adjacent to the site. T5.1OA: Downspout full infiltration systems T5.10A: A design infiltration of 4.0 (Volume III, Chapter 3) Yes inches per hour should be used for preliminary design. A design infiltration of 4.0 inches per Bioretention (Volume V, Chapter 7) Yes hour should be used for design. Dispersion is not recommended due to T5.1013: Downspout dispersion systems No sloped topography adjacent to the site. (Volume III, Chapter 3) T5.10C: Perforated stub -out connections Yes No limitations, (Volume III, Chapter 3) Ofh'er Haid,/Surfaces„ '' , / Full dispersion is not recommended T5.30: Full dispersion (Volume V, Chapter 5) No due to sloped topography adjacent to the site. Near -surface soils generally have a higher fines content and a design T5.15: Permeable pavement (Volume V, Yes infiltration rate of 1.0 inch per hour Chapter 5) should be used for design of permeable avement. A design infiltration of 4.0 inches per Bioretention (Volume V, Chapter 7) Yes hour should be used for design. T5.12: Sheet flow dispersion Full dispersion is not recommended T5.11: Concentrated flow dispersion (Volume No due to sloped topography adjacent to V, Chapter 5) the site. Earth Solutions NW, LLC Select Homes, Inc. December 29, 2016 Revised June 6, 2017 ES -4937.01 Page 16 In our opinion, the soils observed at the test pit locations are generally suitable for support of utilities. In general, the soils observed at the test pit locations should be suitable for use as structural backfill in the utility trench excavations, provided the soil is at or near 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. Utility trench backfill should be placed and compacted to the specifications of structural fill provided in this report, or to the applicable requirements of the City of Edmonds. 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 detailed in the Site Preparation and Earthwork section of this report. It is possible that soft, wet, or otherwise unsuitable subgrade areas may still exist after base grading activities. Areas of unsuitable or yielding subgrade conditions may require remedial measures such as overexcavation and replacement with structural fill or thicker crushed rock sections prior to pavement. For relatively lightly loaded pavements subjected to automobiles and occasional truck traffic, the following sections can be considered for preliminary design: Two inches of hot mix asphalt (HMA) placed over four inches of crushed rock base (CRB), or; • Two inches of HMA placed over three inches of asphalt treated base (ATB). The HMA, CRB and ATB materials should conform to WSDOT specifications. LIMITATIONS 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. A warranty is not expressed or implied. Variations in the soil and groundwater conditions observed at the boring location may exist, and may not become evident until construction. ESNW should reevaluate the conclusions 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. Earth Solutions NW, LLC Reference: NORTH Snohomish County, Washington Map 454 By The Thomas Guide Rand McNally Vicinity Map 32nd Edition 612 - 7th Avenue S. Edmonds, Washington NOTE: This plate may contain areas of color. ESNW cannot be Drwn. MRS Date 06/06/2017 Proj. No. 4937.01 responsible for any subsequent misinterpretation of the information resulting from black & white reproductions of this plate. Checked HTW Date June 2017 Plate 1 Y r vj"iobse � F a �s � r — shit Driv vray i Wo 110 I � p 0 1 I LEGEND TP -1 I Approximate Location of ESNW Test Pit, Proj. No. I ES -4937, Dec. 2016 Subject Site Existing Building Slope Stability Cross -Section 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. NORTH 0 25 50 100 1"=50' --_...--- ......Scale in Feet Earth Solutions NWIvc Test Pit Location Plan 612 - 7th Avenue S. Edmonds, Washington NOTE: This plate may contain areas of color. ESNW cannot be responsible for any subsequent misinterpretation of the information Drwn. MRS Date 06/06/2017 Proj. No. 4937.01 resulting from black &white reproductions of this plate. Checked HTW Date June 2017 Plate 2 Earth Solutions NW u. FOUNDATIONS ADJACENT TO SLOPES 612 - 7th Avenue S. Edmonds, Washington Drwn. MRS Date 06/06/2017 Proj. No. 4937.01 Checked HTW I Date June 2017 Plate 3 111-111— III —111 -III r NOTES: 18" Min. 0 0 O �' po o Oo o0 Q. Oc 0 0 0 0 o O -" Q�� o� '°� o, 0 0 0 o p '°p o0 000 80 O g o o 0 0 0 0' 0 00 0 0 0 0 O o0 Qo oQ o 9 o o 0 0 0 0 o-00. OO O00 , :. I Op p 0 0 0 00 0 oQo .0 .0 Oo Oo 0 oO a o 00 ' 0 0 B 00 00 0 0 0 o apo ...0 = p o 0 0o 00,00 000 0 00 � o0 .0 o 0. 00 00 0 00 0 e o Q 0000 0 0 0 0 0 0 • 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', po 0 Q 0 o Free Draining Structural Backfill o W .11 r•r•r• 1 inch Drain Rock Structural Fill � Perforated Drain Pipe (Surround In Drain Rock) SCHEMATIC ONLY - NOT TO SCALE NOTA CONSTRUCTION DRAWING 1KEarth Solutio NW Lu RETAINING WALL DRAINAGE DETAIL 612 - 7th Avenue S. Edmonds, Washington Drwn. MRS Date 06/06/2017 Proj. No. 4937.01 Checked HTW Date June 2017 Plate 4 Perforated Rigid Drain Pipe (Surround with 1" Rock) 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: F77— 77 171 Surface Seal; native soil or other low permeability material. .w 1 Drain Rock SCHEMATIC ONLY - NOT TO SCALE NOTA CONSTRUCTION DRAWING FOOTING DRAIN DETAIL 612 - 7th Avenue S. Edmonds, Washington Drwn. MRS Date 06/06/2017 Proj. No. 4937.01 Checked HTW Date June 2017 Plate 5 Appendix A Subsurface Exploration ES -4937.01 The subsurface conditions at the site were explored by excavating two test pits at the approximate locations illustrated on Plate 2 of this report. The test pit logs are provided in this Appendix. The subsurface exploration was completed on December 2, 2016. The test pits were excavated to a maximum depth of nine feet below existing grades. Logs of the test pits advanced by ESNW are presented in Appendix A. 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 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. TYPICAL MAJOR DIVISIONSSYMBOLS GRAPH LETTER DESCRIPTIONS CLEAN . GRAVELS, GRAVEL - GRAVEL GRAVELS `wrWELL-GRADED G �!� SAND MIXTURES, LITTLE OR NO ', so FINES AND GRAVELLY GRAVELS, SOILS OR NO FINES)GP ° & POORLY -GRADED GRAVEL SAND MIXTURES, LITTLE (LITTLE 0OR ply - NO FINES COARSE 0 ° '° ° GRAINED GRAVELS WITH D GM SILTY GRAVELS, GRAVEL -SAND - SOILS MORE THANFINES SILT MIXTURES OF COARSEE � a FRACTION RETAINED ON NO. 4 SIEVE (APPRECIABLEGC CLAYEY GRAVELS GRAVEL - SAND - AMOUNT OF FINES) CLAY MIXTURES CLEAN SANDS SW DED SANDS, GR LITTLE MORE THAN 50% SAND ANDS, OR NO FINEASVELLY OF MATERIAL IS AND LARGERTHAN SANDY NO. 200 SIEVE SOILSPOORLY-GRADED NO FINES) SP SANDS, GRAVELLY SAND, LITTLE OR NO SIZE (LITTLE OR FINES SANDS WITHSILTY r SM SANDS, SAND - SILT MORE THAN 50% FINES MIXTURES OF COARSE FRACTION PASSING ON NO. 4 SIEVE (APPRECIABLE S`+ CLAYEY SANDS, SAND - CLAY AMOUNT OF FINES) MIXTURES INORGANIC SILTS AND VERY FINE ML SANDS, ROCK FLOUR, SILTY OR CLAYEY FINE SANDS OR CLAYEY SILTS WITH SLIGHT PLASTICITY SILTS INORGANIC CLAYS OF LOW TO FINELIQUID LIMIT AND CL MEDIUM PLASTICITY, GRAVELLY GRAINED LESS THAN 50 CLAYS CLAYS, SANDY CLAYS, SILTY SOILS CLAYS, LEAN CLAYS — „.....- — = OL ORGANIC SILTS AND ORGANIC — - SILTY CLAYS OF LOW PLASTICITY MORE THAN 50% INORGANIC SILTS, MICACEOUS OR OF MATERIAL IS NIH DIATOMACEOUS FINE SAND OR SMALLER THAN SILTY SOILS NO. 200 SIEVE SIZE SILTS AND LIQUID LIMIT CH INORGANIC CLAYS OF HIGH GREATER THAN 50 PLASTICITY CLAYS OH ORGANIC CLAYS OF MEDIUM TO HIGH PLASTICITY, ORGANIC SILTS ' HIGHLY ORGANIC SOILS s ei..eai "' ` PT HUMUS, SWAMP SOILS WITH „ „ „ HIGH ORGANIC CONTENTS HIGH 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. 1805 - 136th Place N.E., Suite 201 PAGE 1 OF 1 Bellevue, Washington 98005 40 Earth Solutions NW TEST PIT NUMBER TP -1 Telephone: 425-449-4704 Fax: 425-449-4711 _�Inc.PROJECT NAME 612-a7th Avenue S CLIENT elec_ _4mQS, n „ PROJECT NUMBER 493 _. w � PROJECT LOCATION Eflrlyorl4 �VV� ... COMPLETED ..DATE STARTED 92 ��..��.w Wm..... ..�,.-..._-�..uu�_........-�. /2116 1212/16 . / .6 s GROUND ELEVATION 112 ftm TEST PIT SIZE EXCAVATION CONTRACTOR Client Provided GROUND WATER LEVELS: EXCAVATION METHOD AT TIME OF EXCAVATION — LOGGED BY HTW CHECKED BY HTW AT END OF EXCAVATION — NOTES Syrfaoe Conditions Crushed rock � � �. � ,. AFTER EXCAVATION W w W LU g TESTS a. O MATERIAL DESCRIPTION Cd ❑ Q Z V, V) Q OC o.b 4"- 6" Crushed rock -�� ...... SP- medium Light brown poorly graded SAND with silt, loose to dense, damp SM 1.5110.5 .. ...... -..._ .w....mw�. ....... . Gray poorly graded SAND, loose..__ . a.. to medium dense dam p -oxide staining -sparse roots MC = 6.60% -pocket of increased gravel content Fines = 0.94% [USDA Classification: slightly gravelly SAND] ISP -becomes medium dense, moist MC = 5.20% Test pit terminated 8.5 feet below existing grade. .mi ..... No groundwater encountered during excavation. Caving observed through upper 6 feet. Bottom of test pit at 8.5 feet. Earth Solutions NW Iva TEST PIT NUMBER TP -2 1805 -136th Place N.E., Suite 201 Bellevue, Washington 98005 PAGE 1 OF 1 Telephone: 425-449-4704 Fax: 425-449-4711 CLIENT ..Sele......ct Homes Inc. ®„ „ _ w-� a . ............... o„ PROJECT NAME 612 - 7th Avenue S PROJECT NUMBER 4937y PROJECT LOCATION Edmonds. Washingten a. DATE STARTED 1212116 COMPLETED 1212116 mmm _ GROUND ELEVATION 107 ftTEST PIT SIZE _....._ EXCAVATION CONTRACTOR Client Provided GROUND WATER LEVELS: EXCAVATION METHOD AT TIME OF EXCAVATION —_w.. _.. LOGGED BY HTW —„ CHECKED BY HTW AT END OF EXCAVATION — _-W. ..m. NOTES Death of Topsoil & Sad m24 : weedsm AFTER EXCAVATION W IL r Of U a. a j TESTS O MATERIAL DESCRIPTION LU Cd ❑ ¢Z 0 Darn brown sandy TOPSOIL to 24" TPSL fir. ro� k� .......... .e 2,0 _ _ 7CiJ,tl' Brown poorly graded SAND, loose to medium dense, damp to moist MC = 10.00% Fines = 3.53% [USDA Classification: gravelly SAND] -becomes gray 5 -becomes medium dense, moist SP -pocket of increased gravel content MC = 4.40% MC = 4,00% Fines - 0-07% ep Classification: very AND] [ ry gravelly SAND] ...� ,. m..m.,_ _ o pit terminated at 9.0 ------ fejt below Test grade. No groundwater encountered during excavation. Caving observed through upper 6 feet. Bottom of test pit at 9.0 feet. a C7 r� �II asp Appendix B Laboratory Test Results ES -4937.01 Earth Solutions NW, LLC 6 4 3 2 1,5 1 W 112WI3 3 4 6 610 1416 20 30 40 50 60 100140'200 100 95 _ - L 90 85 . , ° . 80 . . n ° w 75 70 65 60 55 - - , Z _ LL F- 45 Lu„ CJ° w a" 35 ' " " " . 30 25 . " " 20 15 • . . . . " . „ 5 " p 100 10 1 0,1 0.01 0"001 GRAIN SIZE IN MILLIMETERS GRAVEL e SAN COBBLES C SILT OR ITmm „ LAY ITITrse fine coarse medium fine Specimen Identification i,- Classification Cc FCU _ TP -1 4.00ft _.USDA�IT : Gray Slightly Gravelly Sand. USCS: SP. 1.00 2.55 TP -2 3.00ft. USDA: Brown Gravelly Sand. USCS: SP. 0.89 3.37 TP -2 8.50ft. USDA: Brown Very Gravelly Sand. USCS: SP with Gravel. 0.45 6.96 Specimen Identification D100 D60 D30 D100 PI LL PL TP -1 4.Oft. 19 0.451 0.283 0.177 0.94 ... ..... _.._ ___ _. __-.....WW..._ Z TP -2 3.Oft. 19 0.683 0.351 0.202 3.53 -A TP -2 8.5ft. 19 2.046 0.521 0.294 0.07 Appendix C Slope Stability Analysis Results ES -4937.01 Earth Solutions NW, LLC (D N U) t O C0 O C C N O oQV Mti US rn I CL ' N Cb Irl O m W co a. cn Alm ME 6/6/2017 71111 Ave S Short Plat 7th Ave S Short Pat Report generated using GeoStudio 2016 Copyright © 1991-2017 GEO-SLOPE International Ltd. File information File Version: 8.16 Title: 7th Ave S Short Plat Created By: Henry Wright Last Edited By: Terry Dunn Revision Number: 15 Date: 5/18/2017 Time: 8:19:35 AM Tool Version: 8.16.2.14053 File Name: 612, Proposed, Static.gsz Directory: C:\Users\terry.dunn\Desktop\4937.01 SlopeW\ Last Solved Date: 5/18/2017 Last Solved Time: 8:19:38 AM Project Settings Length(L) Units: Feet Time(t) Units: Seconds Force(F) Units: Pounds Pressure(p) Units: psf Strength Units: psf Unit Weight of Water: 62.4 pcf View: 2D Element Thickness: 1 Analysis Settings 7th Ave S Short Plat Kind: SLOPE/W Method: Morgenstern -Price Settings Side Function Interslice force function option: Half -Sine PWP Conditions Source: (none) Slip Surface Direction of movement: Right to Left Use Passive Mode: No Slip Surface Option: Entry and Exit Critical slip surfaces saved: 1 Resisting Side Maximum Convex Angle: 1 ° Driving Side Maximum Convex Angle: 5 ° Optimize Critical Slip Surface Location: No Tension Crack Tension Crack Option: (none) F of S Distribution F of S Calculation Option: Constant file:///C:/Users/terry.dunn/Desktop/4937.01%20slopew/612,%20proposed%20static.html 1/4 6/62017 7th Ave S Short Plat Advanced Number of Slices: 30 F of S Tolerance: 0.001 Minimum Slip Surface Depth: 0.1 ft Search Method: Root Finder Tolerable difference between starting and converged F of S: 3 Maximum iterations to calculate converged lambda: 20 Max Absolute Lambda: 2 Materials Medium Dense Sand Model: Mohr -Coulomb Unit Weight: 120 pcf Cohesion': 0 psf Phi': 36' Phi -B: 0 ' Slip Surface Entry and Exit Left Projection: Range Left -Zone Left Coordinate: (1, 90.2) ft Left -Zone Right Coordinate: (22.65126, 98.69772) ft Left -Zone Increment: 4 Right Projection: Range Right -Zone Left Coordinate: (36, 101) ft Right -Zone Right Coordinate: (138.65507, 111.83793) ft Right -Zone Increment: 8 Radius Increments: 4 Slip Surface Limits Left Coordinate: (0, 90) ft Right Coordinate: (150, 112) ft Surcharge Loads Surcharge Load 1 Surcharge (Unit Weight): 250 pcf Direction: Vertical Coordinates X. (ft) Y � ft) _. , 50 10 _,.®.. 60 102 80 112 .. 100 ,... 112 file:///C:lUsers/terry.dunn/Desktopl4937.01%20slopew/612,%20proposed,%20sta0c.html 214 6/6/2017 Seismic Coefficients Horz Seismic Coef.: 0 Points 7th Ave S Short Plat ions Material Points Area (ft Region 1 Medium Dense Sand 5,6,1 2,3,4,7,8 6,808.5 Current Slip Surface Slip Surface: 47 F of S: 2.096 Volume: 97.600046 ft3 Weight: 11, 712.006 lbs Resisting Moment: 327,935.17 lbs -ft Activating Moment: 156,517.74 lbs -ft Resisting Force: 7,596.6031 lbs Activating Force: 3,624.2126 lbs F of S Rank (Analysis): 1 of 225 slip surfaces F of S Rank (Query): 1 of 225 slip surfaces Exit: (6.7592069, 91.351841) ft Entry: (36, 101) ft Radius: 40.243453 ft Center: (9.7289939, 131.48557) ft Slip Slices Point 1 0 60 Point 20 X (ft) 90 Point 3 10 92 Point 4. 2, 7 ..... 1_011 Point 5 150 112 Point 6 150 60� Point 7 m 60 101 Point 8 801 11 7th Ave S Short Plat ions Material Points Area (ft Region 1 Medium Dense Sand 5,6,1 2,3,4,7,8 6,808.5 Current Slip Surface Slip Surface: 47 F of S: 2.096 Volume: 97.600046 ft3 Weight: 11, 712.006 lbs Resisting Moment: 327,935.17 lbs -ft Activating Moment: 156,517.74 lbs -ft Resisting Force: 7,596.6031 lbs Activating Force: 3,624.2126 lbs F of S Rank (Analysis): 1 of 225 slip surfaces F of S Rank (Query): 1 of 225 slip surfaces Exit: (6.7592069, 91.351841) ft Entry: (36, 101) ft Radius: 40.243453 ft Center: (9.7289939, 131.48557) ft Slip Slices PWP Base Normal Stress Frictional Strength X (ft) Y (ft) (psf) _ (psf)11 �� (psf) Slice 1 7.2993391 91.319169 0 17.5961 12.784315_. . .... Slice 2 m 8.3796035 91.268374 0 51.71_771 7 5 5 75116 37.575116 ..60.3� Slice 3 9.4598678_ _ 9_1.246638 0 83.008599 _ ®,. 09277 ... __.. ..... Slice 4 ...10.5 91.252608 p 0 ®. ,.., . ...... 130.86855 _ ..m® .. 95.081566 _ k . _.. Slid..e,........e Slice 5 _ 11.5 .. 91.284216 0 195.27389 141.87479 Slice 6 12.5 91.340755 0 255.97151 185.97419 _.. .. _.. Slic...... e 7 �_.m 13.591.422331 _ 0 312.14851 m..,., 226.78917 e� Slice 14.5 �... ® ....... _ .. 91.529097 0 ... ®.,,A.... 363.13453 263.83268 � _8 Slice 9 15.5 91.661255 0�_...m,.,..... 408.44598 296.75338 16.5 91.81906 0 447.80981 325,35287 10Ce Cohesive Strength file:/!/C:/Users/terry.dunn/Desktop/4937.01%20slopew/612,%20proposed,%20statc.html 34 6/6/2017 file:!!/C:lUserslterry.dunn/Desktop/4937.01%20slopew/612,%20proposed,%20static.html 4/4 7th Ave S Short Plat Slice 17.5 92.00282 0 481.16618 349.58769 0 11 Slice 18.5 92.212898 0 508.65229 369.55752 0 12 v.. ..� ... . � ..............,, .. � .,..r. �_,.. ,....._.. ...........�_ ....�. Slice 19.5 92.44972... 0 530.57 187 385.48303 0 13 Slice 20.5 92.713777 0 547.35577 397.67725 0 14 ..... �_� .......� ....... _ .. _ _....�....... w.............. n..... Slice ....,w .. 21.5 w ., 93.......,.. _ .00563 0 559.51911 406.51443 0 15 � � �0 Slice 22.5 �93.325916� 0�.. 567.61962 412.39979 16 �... . m..._ �M. ,._.. �_, ...... Slice 23.5 ® 93.675359 0 572.22045 415.74249 0 17 2 m...a . a �..... ,��. . ... Slice ,. 24.5 .... .94.054777 0 573.85921..... 416.933.12... 0........ 18 ......... ....... ..... .... ........ ...... ...... ... . Slice 25.5 94.465092 0 573.02377 416.32614 0 19 Slice 26.5 94.907344 0 570,13449 414.22695 0 20 .95.382709 .,�.�539.41588. � �..m . ................ Slice 27.5....... 0 391.90858.. 0...,... 21 �_ ...... ._....... m..� _... .._ .... ®... �..... �....... ......._ w.. Slice 28.5 95.892515 0 482.145 350.29885 0 22 23Ce 29.5 96.438266 0 h�424.5218 308.43314 0 .... �.. �� _ ,, ..... .,m . .m .. . ............................. .. _ .. Slice . 30 ........e ...... 5 . ... 97.021672 0 366.12717 266.00696 0 24 Slice 31.5 97.644684 0 306.4049 222.61619 0 25 . _ . _ ..... ...._244.66153 ....� .,... �e�..� ..®.. ...w... _.. � .,. �........ . __e ......... . Slice 32.5 98.309536.,..0. 17.7.. 75701 0 26 Slice 33.5 99.018802 0 180.06158 130.82239 0 27 .. _ Slice __...34.5, .....�_. 99.77547... 0��.. 111.61745 81.094825 0 28 Sluice 35.5 100.58303 0 38.173519 27.734685 0 file:!!/C:lUserslterry.dunn/Desktop/4937.01%20slopew/612,%20proposed,%20static.html 4/4 N U) N t O c N O C C N O o< c') (D CD ti V d N (nr O N wcOaCD m CO a) d) 0 E N 2 Ann 6/6/2017 7th Ave S Short Plat 7th Ave S Short Plat Report generated using GeoStudio 2016. Copyright ® 1991-2017 GEO-SLOPE International Ltd. File Information File Version: 8.16 Title: 7th Ave 5 Short Plat Created By: Henry Wright Last Edited By: Terry Dunn Revision Number: 17 Date: 6/6/2017 Time: 8:14:07 AM Tool Version: 8.16.2.14053 File Name: 612, Proposed, Seismic.gsz Directory: C:\Users\terry.dunn\Desktop\4937.01 SlopeW\ Last Solved Date: 6/6/2017 Last Solved Time: 8:14:11 AM Project Settings Length(L) Units: Feet Time(t) Units: Seconds Force(F) Units: Pounds Pressure(p) Units: psf Strength Units: psf Unit Weight of Water: 62.4 pcf View: 2D Element Thickness: 1 Analysis Settings 7th Ave S Short Plat Kind: SLOPE/W Method: Morgenstern -Price Settings Side Function Interslice force function option: Half -Sine PWP Conditions Source: (none) Slip Surface Direction of movement: Right to Left Use Passive Mode: No Slip Surface Option: Entry and Exit Critical slip surfaces saved: 1 Resisting Side Maximum Convex Angle: 1 Driving Side Maximum Convex Angle: 5 ° Optimize Critical Slip Surface Location: No Tension Crack Tension Crack Option: (none) F of S Distribution F of 5 Calculation Option: Constant file:MC:/Users/terry.dunn/Desktop/4937.01%20slopew/612,%20proposed%20seismic.html 1/4 6/6/2017 7th Ave S Short Plat Advanced Number of Slices: 30 F of S Tolerance: 0.001 Minimum Slip Surface Depth: 0.1 ft Search Method: Root Finder Tolerable difference between starting and converged F of S: 3 Maximum iterations to calculate converged lambda: 20 Max Absolute Lambda: 2 Materials Medium Dense Sand Model: Mohr -Coulomb Unit Weight: 120 pcf Cohesion': 0 psf Phi': 36 ° Phi -B: 0 ° Slip Surface Entry and Exit Left Projection: Range Left -Zone Left Coordinate: (1, 90,2) ft Left -Zone Right Coordinate: (22.65126, 98.69772) ft Left -Zone Increment: 4 Right Projection: Range Right -Zone Left Coordinate: (36, 101) ft Right -Zone Right Coordinate: (138.65507, 111.83793) ft Right -Zone Increment: 8 Radius Increments: 4 Slip Surface Limits Left Coordinate: (0, 90) ft Right Coordinate: (150, 112) ft Surcharge Loads Surcharge Load 1 Surcharge (Unit Weight): 250 pcf Direction: Vertical Coordinates X (ft) ...Y (ft)... .102..�,_ 50 _. �. ,60 102 80 112 100 112 file:/!/C:/Users/terry.dunnlDesktop/4937.01%20slopew/612,%20proposed,%20seismic.html 214 616/2017 7th Ave S Short Plat Seismic Coefficients Horz Seismic Coef.: 0.2 Points Regions Material Points Area (ftp) Region 1 Medium Dense Sand 5,6,1,2,3,4,7,8 6,808.5 Current Slip Surface Slip Surface: 46 F of S: 1.244 Volume: 46.135607 ft' Weight: 5,536.2729 lbs Resisting Moment: 755,509.53 lbs -ft Activating Moment: 607,292.27 lbs -ft Resisting Force: 3,350.0145 lbs Activating Force: 2,692.9189 lbs F of S Rank (Analysis):1 of 225 slip surfaces F of S Rank (Query): 1 of 225 slip surfaces Exit: (10.749218, 92.396645) ft Entry: (36, 101) ft Radius: 213,19855 ft Center: (-45.24947, 298.10947) ft Slip Slices X (ft) ] Y (ft) Slice 1 11.17687 92.514015 X (ft) Y (ft) 12.032175 92.750673 Point 1 0 60 0 a11111111 . Point.2.�. 0.. .... ...90. me Slice 5 Point 3 10 2 92 15.45339 _ .. ._ 93.7358340 Point 4 , 27 101 0 Point 5 .,1.50 ......... . Slice 9 Point 6 150 60 175.0......17 17 Point 7 60 101 0 Point 8 8 0 111 Regions Material Points Area (ftp) Region 1 Medium Dense Sand 5,6,1,2,3,4,7,8 6,808.5 Current Slip Surface Slip Surface: 46 F of S: 1.244 Volume: 46.135607 ft' Weight: 5,536.2729 lbs Resisting Moment: 755,509.53 lbs -ft Activating Moment: 607,292.27 lbs -ft Resisting Force: 3,350.0145 lbs Activating Force: 2,692.9189 lbs F of S Rank (Analysis):1 of 225 slip surfaces F of S Rank (Query): 1 of 225 slip surfaces Exit: (10.749218, 92.396645) ft Entry: (36, 101) ft Radius: 213,19855 ft Center: (-45.24947, 298.10947) ft Slip Slices X (ft) ] Y (ft) Slice 1 11.17687 92.514015 0 Slice 2 12.032175 92.750673 0 Slicew..... 3 ... 12.887479 92.99117 0 .. .,. Slice 4 ...... � . ,,, .......,.. 13.742783 93.23552 0 Slice 5 14.598088 93.483737 0 Slice 6 . 92 15.45339 _ .. ._ 93.7358340 ................... 59.574619 Slice 7 16.3086.. 96 93,991827 ..4 ....._.. 0 Slice 8 ....17.1640�.. ..... YOY 01 94.25173 0 Slice 9 8.019305 94.515558 0 Slice 175.0......17 17 127.15742 ........ 18.874609 94,783326 0 10 PWP Base Normal Stress Frictional Strength (psf) (psf) (psf) 11.418751 8.2962084 ..u_ _ 34.57.,.,. ._ ..____ 0493 25.116933 58.122594 42.228536 . -......u.... 81.997429 ................... 59.574619 5.98714 77.004162 ' 129.76526 94.279977 _._....., 152.92196111,10431 .. .� _....... � .,.,. 175.0......17 17 127.15742 ........ _ . ...m 195.64222 ®�_..._ .m ..... 142.1424 214,479 1 155.82811 Cohesive Strength 9 file:l//C:lUserslterry.dunn/Desktopl4937.01%20slopewl612,%20proposed,%20seismic.html 3/4 6/6/2017 file:!!/C:lUsers/terry.dunn/Desktopl4937.01%20slopew/612,%20proposed,%20seismic.html 4/4 7th Ave S Short Plat Slice 19.729913 95.05505 0 231.34621 168.08286 0 11 _ _.... _.- -------- _ ...._ ... ................ __ , ...... .., .. Slice �., 20.585218 95.330745 0 246.2251 178.89301 0 12 . .. .,... ... Slice ®.. .�............. 21.440522 195.610429 0 259.26099 188.36414 0 13 ..m_.0 -- I I - - w.va . ..m .... .... ...... ---. .... Slice --- . 22.295826 95.894117 0 270.74168 196.70535 0 14 .. ------ �.. Slice .w.. ,..m 23.151 131 e. m . _ 96. 181826 0 281.05793 204.20054 0 15 ® .. �U211.172 ,, e.e _ .... .. .......� Slice � 24.006435... 96,473574. O..m 290.65382 36 0 16 .. �, ._m �.... _ , ....�. � d . �... _ Slice Slice 24.861739 96.769378 0 299.97592 217.94526 0 17 - _ .... .. �..,.� _ .. _....,.,., .. �. ...... 18Ce 25,717044 ._. 97,069256 0 309.4293 224.81355 0 Slice 348 97,373226 0 319.34604 232.01848 0 19 _ , ZlCe 27.409091 97.674534 0 309.00878 224.50802 0 _ _ a..,.,202.5650��. Slice .� 28.227273 97.973022 0. 278.80693..._....... 9 0 ... ........ .._ . -... , 11111-11-11 , m.. -.1 ....w .. __...w �.. Slice 29.045455 .. 98.275306 0 249.55798 181.31449 0 22_ _ ._. ..... _m..._ �. m .... .._. ,. ®,,.. .... �...r._ ... _. ., Slice 29.863636..... 98.581403 0 220.97835 160.55017 0 23 ...... ....... . ,, .m ,..._.�.Y..... , .. ..�. ................. _. ............ .., . .,.. Slice 30.681818 98.89133 0 192.76583 140.05257 0 24 ,- ......... ..... Slice ...... .. 31.5 99.205106 0 164.62157 1 119,60457 0 25 m ®0� n..,.,......, ... ..._ .....�.. _ ..�........ �._ _..... �..r....r _� Slice -32.318182 � ..99.522748 136.26453 99............... 001978 0 26 �..® ,�. .. . �.a..... . ... �... �........m .. Slice _.:... ........ 1 33.136364 99.844276 0 107.43988 78.059641 0 27 w� ,,....,............77.922829 _ w_ .. �,, � ...... �....m.,.. Slice 33.954545 100.16971 56.614249.... 0 28 Slid e 34.772727 100.49906 0 47.520056 34.525342 0 29 Slice,,,,,.,., 35 590909 100.83236 0 16.069963 11.675511 0 30 . file:!!/C:lUsers/terry.dunn/Desktopl4937.01%20slopew/612,%20proposed,%20seismic.html 4/4 a� cn 0 .E Z 0 0 c U) 0 W :3-o c c a> 0 CD v v ~00. " r0 wcoCLcn cu U) CD N 0 cn .CU 0 N c� t O L Zr.+ O O CO O N 7 'p C C N O a M N � O N C' U) , 2 4 W Co a cn C C/) cn C E co CU .i V (D �NO/ 6/6/2017 7th Ave S Short Plat 7th Ave S Short Plat Report generated � using GeoStudio 2016. Copyright ©1991 2017 GEO-SLOPE International Ltd. File information File Version: 8.16 Title: 7th Ave S Short Plat Created By: Henry Wright Last Edited By: Terry Dunn Revision Number: 21 Date: 5/18/2017 Time: 9:05:39 AM Tool Version: 8.16.2.14053 File Name: 612 North, Proposed, Static.gsz Directory: C:\Users\terry.dunn\Desktop\4937.01 SlopeW\ Last Solved Date: 5/18/2017 Last Solved Time: 9:05:40 AM Project Settings Length(L) Units: Feet Time(t) Units: Seconds Force(F) Units: Pounds Pressure(p) Units: psf Strength Units: psf Unit Weight of Water: 62.4 pcf View: 2D Element Thickness: 1 Analysis Settings 7th Ave S Short Plat Kind: SLOPE/W Method: Morgenstern -Price Settings Side Function Interslice force function option: Half -Sine PWP Conditions Source: (none) Slip Surface Direction of movement: Right to Left Use Passive Mode: No Slip Surface Option: Entry and Exit Critical slip surfaces saved: 1 Resisting Side Maximum Convex Angle: 1 ° Driving Side Maximum Convex Angle: 5 ° Optimize Critical Slip Surface Location: No Tension Crack Tension Crack Option: (none) F of S Distribution F of S Calculation Option: Constant file:///C:JUserslterry.dunn/Desktop/4937.01 %20slopew/612%20north,%20proposed,%20static.htm 1 1/4 6/6/2017 7th Ave S Short Plat Advanced Number of Slices: 30 F of S Tolerance: 0.001 Minimum Slip Surface Depth: 0.1 ft Search Method: Root Finder Tolerable difference between starting and converged F of S: 3 Maximum iterations to calculate converged lambda: 20 Max Absolute Lambda: 2 Materials Medium Dense Sand Model: Mohr -Coulomb Unit Weight: 120 pcf Cohesion': 0 psf Phi': 36 ° Phi -B: 0' Rockery Model: Mohr -Coulomb Unit Weight: 145 pcf Cohesion': 0 psf Phi': 60' Phi -B: 0' Slip Surface Entry and Exit Left Projection: Range Left -Zone Left Coordinate: (13, 100) ft Left -Zone Right Coordinate: (28, 103) ft Left -Zone Increment: 4 Right Projection: Range Right -Zone Left Coordinate: (36, 105) ft Right -Zone Right Coordinate: (71.31583, 105) ft Right -Zone Increment: 4 Radius Increments: 4 Slip Surface Limits Left Coordinate: (0, 100) ft Right Coordinate: (75, 105) ft Surcharge Loads Surcharge Load 1 Surcharge (Unit Weight): 250 pcf Direction: Vertical Coordinates X (ft) I Y (ft) l file:///C:/Userstterry.dunn/Desktop/4937.01 %20slopew/612%2Onorth,%20proposed,%20static.htm I 2/4 6/6/2017 7th Ave S Short Plat Points ...... , .......,X...ft)... .._........... X ,..Y..�.ft ...,�, 11-1-111-1- .. Point 1 0 80 Point 2 0 100 1100 ,-" Point 3 30 Point 4 30 103 Point 5 34 105.... Point 6 75 80 Point 7 75 105 Point 8 28 100 Point 9 28 103 ons nm . .. —11,11,1111, a...._..,..... Material Points Area i .. .m�,.... �..,.,,.... _o.o... Region 1 Rockery 9,4,3,8 6 Region 2 Medium Dense Sand 2,8,3,4,5,7,6,1 1,721 Current Slip Surface Slip Surface: 53 F of S: 1.710 Volume: 23.554744 ft3 Weight: 2,976.3639 lbs Resisting Moment: 27,812.853 lbs -ft Activating Moment: 16,262.383 lbs -ft Resisting Force: 2,052.2271 lbs Activating Force: 1,199.841 lbs F of S Rank (Analysis): 1 of 125 slip surfaces F of S Rank (Query): 1 of 125 slip surfaces Exit: (22, 100) ft Entry: (36, 105) ft Radius: 11.857063 ft Center: (25.892937, 111.19978) ft Slip Slices PWP Base Normal Stress X (ft) Y (ft) _ (psf) (psf) Slice 1 22.230769 99.925043 0 11.03 3052 Slice 2 22.692308 99.78537 8 �. 0 3 � 33.106652 Slice 3 23.153846 99.665867 0 54.069831 ,.., .,w Slice 4 .... 23 615385 ,... .... ..... 99.565886 0 , ... 73.14825 u, I'll 1-11.m Slice 5 .... .., 24 076923 99.484935 0 89.509474 Slice 6 24.538462 99.422621 0 102.37286 _ Slice ? 25 99 ,A. .....A... 378649 0 ..- 111.12118 Slice 8 25.461538 99.352814 0 115.38719 Slice 9 1 25.923077 99.344997 0 1 115.09566 Cohesive Strength file:l//C:lUsers/terry.dunn/Desktop/4937.01%20slopewl612%20north,%20proposed,%20static.html 3/4 6/6/2017 file:/l/C:IUserslterry.dunn/Desktop/4937.01 %20slopew/612%20north,%20proposed,%20static.htm I 414 7th Ave S Short Plat Slice 26.384615 99.355163 0 110.45451 80.249897 0 10 .... .... ., ...� _.,..,_. 1 Slice ...... .... ......_........e_..., ............ m 26.846154 99.383359 0 101.90216 74.036256 0 11 .�_. Slice ......... .. ..... ..._... _� ... .....m. .. ....m _._ ,..s. 27.3076 92 99,429713 0 90.027453 65.408773 0 12 ... . Sli m ... .. ........... .. ,_ �. ,m ®_, ....... ..0 2.... 7.769231 ! 99.494442 0 75.481626 54.840611 0 13ce . ,,._.�._,. Slice ...., ...e..am �.........�._ 28.223234 99.576187 0 516.66432 375.3786 0 14 �. ......_. �...® m.n............. ...... ..... ........ ... .... _ .. �.,. .. ...e.. ..... ....._ __ Slice L 28,669703 99.674726 0 480.96508 349.44158 0 15 . .v.. v. ..99.79158... �. ._ ... _ ..._ _... ..,.........w.., ........,._.......... . l.. Slice 29. 116172 44 3.5686 322.27145 0 16 _.os.... .� Slice ......... �� ........ _ �. m..........� �. , .e,.w...... 29.56264 99.927327. 0 405.53371.... 294.6374. 9 0 17 Slice 29 892937 100.03837 0 428.83011 742.75553 0 18 ._.�e.,�n.. Slice .,, 0_s�., _294,33183 ..�. � �.... ........�.,� .__.� �_..e� ...W� .... 30.222222 100.163.91 2.13. .84459 0 19 Slice 30.666667 100.34885 0 1 281. 204.66374 0 .69547 Slice 31.111111 100.55556 0 268.29289 194.9262 0 21 .. ... _ Slice ..D . � .... ..� ..... � ...... ...._ , �._. .. ..�,........ �..... 31.555556 100.78533 254.39174............................. 184.82642 0 22 _O..e__24..�.e� ..... .......v_m. �. .. � .m.... .o .... ................... � .. oo .0 Slice 32 101.03973 0.14228 174.47358 0 23 Slice _...._...�.w,.. w .. _ ........_ ....._ ........�.. 32.444444 101.32068_L.. 0 225.58536 163.89736 0 24 Slice 32.888889 101.63051 0� 210.65739 153.05155 0 25 �� � �� . .... . . ... .... . . . . . . .. .. . Slice Slice _ ��® � ����� _ ��� ���� ������� � 33.333333 101.97216 O.m 195.19004 141.81386�� 0 26 Slice 33.777778 102.34932 0 178.90233 129.98015 0 27 ... Slice _ � me. m 34.25m. 102.7959 0 150.34882 109.23481 0 28_ m..�,.. � � ........�. _103.32572 .. ........m M 0...... 109.15019_..,_. 79.302252.. 0..., 29Ce34.75 Slice 35.25 103.92865 0 220.29097 160.05076 0 30 . .. ............. _.... , ..... .. Sli 35.75 104.62518 0 172.56168 125.3734 0 31Ce file:/l/C:IUserslterry.dunn/Desktop/4937.01 %20slopew/612%20north,%20proposed,%20static.htm I 414 a cn 0 s Z 0 Cl) 0 U) N o C) Q U a ~ 0 CbC14 CL 2 O WcoCL(n cc U) cn c CD 0 E CU .i CD cu ��0 LL L .1 E 6/6/2017 7th Ave S Short Plat 7th AveS Short Plat Report generated using GeoStudio 2016. Copyright m 1991-2017 GEO-SLOPE International Ltd. File Information File Version: 8.16 Title: 7th Ave 5 Short Plat Created By: Henry Wright Last Edited By: Terry Dunn Revision Number: 23 Date: 6/6/2017 Time: 8:16:50 AM Tool Version: 8.16.2.14053 File Name: 612 North, Proposed, Seismic.gsz Directory: C:\Users\terry.dunn\Desktop\4937.01 SlopeW\ Last Solved Date: 6/6/2017 Last Solved Time: 8:16:54 AM Project Settings Length(L) Units: Feet Time(t) Units: Seconds Force(F) Units: Pounds Pressure(p) Units: psf Strength Units: psf Unit Weight of Water: 62.4 pcf View: 2D Element Thickness: 1 Analysis Settings 7th Ave S Short Plat Kind: SLOPE/W Method: Morgenstern -Price Settings Side Function Interslice force function option: Half -Sine PWP Conditions Source: (none) Slip Surface Direction of movement: Right to Left Use Passive Mode: No Slip Surface Option: Entry and Exit Critical slip surfaces saved: 1 Resisting Side Maximum Convex Angle: 1 ° Driving Side Maximum Convex Angle: 5 ° Optimize Critical Slip Surface Location: No Tension Crack Tension Crack Option: (none) F of S Distribution F of S Calculation Option: Constant file://lC:lUsersfterry.dunnlDesktop/4937.01%20slopew/612%20north,%20proposed,%20seismic.html 1/4 6/68017 7th Ave S Short Plat Advanced Number of Slices: 30 F of S Tolerance: 0.001 Minimum Slip Surface Depth: 0.1 ft Search Method: Root Finder Tolerable difference between starting and converged F of S: 3 Maximum iterations to calculate converged lambda: 20 Max Absolute Lambda: 2 Materials Medium Dense Sand Model: Mohr -Coulomb Unit Weight: 120 pcf Cohesion': 0 psf Phi': 36 ° Phi -B: 0 ° Rockery Model: Mohr -Coulomb Unit Weight: 145 pcf Cohesion': 0 psf Phi': 60 ° Phi -B: 0 ° Slip Surface Entry and Exit Left Projection: Range Left -Zone Left Coordinate: (13, 100) ft Left -Zone Right Coordinate: (28, 103) ft Left -Zone Increment: 4 Right Projection: Range Right -Zone Left Coordinate: (36, 105) ft Right -Zone Right Coordinate: (71.31583, 105) ft Right -Zone Increment: 4 Radius Increments: 4 Slip Surface Limits Left Coordinate: (0, 100)ft Right Coordinate: (75, 105) ft Surcharge Loads Surcharge Load 1 Surcharge (Unit Weight): 250 pcf Direction: Vertical Coordinates file:///C:/Users/terry.dunn/Desktopt4937.01%20slopew/612%20north,%20proposed "/°20seismic.html 2/4 6!6/2017 7th Ave S Short Plat 35 106 �. 'j. . 7.5 ],._.106� Seismic Coefficients Horz Seismic Coef.: 0.2 Points Regions . . . ...Material -"Points . Points° r�Area (ft2j Region 1 Rockery 9,4,3,8 6 Region 2 Medium Dense Sand 2 8 3 4,5 7, ... 6,1 1,721 Current Slip Surface Slip Surface: 53 F of S: 1.219 Volume: 23.554744 ft' Weight: 2,976.3639 lbs Resisting Moment: 26,477.181 lbs -ft Activating Moment: 21,728.849 lbs -ft Resisting Force: 1,980.7904 lbs Activating Force: 1,625518 lbs F of S Rank (Analysis): 1 of 125 slip surfaces F of S Rank (Query): 1 of 125 slip surfaces Exit: (22, 100) ft Entry: (36, 105) ft Radius: 11.857063 ft Center: (25.892937, 111.19978) ft Slip Slices (ft) Y (ft) Point 1 0 . 80 Point 2 m ._�0 _. . 100......,.. Point 33�0 ..............�.......�������.�����������������......... 100 Point 4...30 22.692308 103. Point 5 34 105 Point 6 .. 5 7 80 Point 7 75 105 Point 8 28 100 Point 9 28 103 Regions . . . ...Material -"Points . Points° r�Area (ft2j Region 1 Rockery 9,4,3,8 6 Region 2 Medium Dense Sand 2 8 3 4,5 7, ... 6,1 1,721 Current Slip Surface Slip Surface: 53 F of S: 1.219 Volume: 23.554744 ft' Weight: 2,976.3639 lbs Resisting Moment: 26,477.181 lbs -ft Activating Moment: 21,728.849 lbs -ft Resisting Force: 1,980.7904 lbs Activating Force: 1,625518 lbs F of S Rank (Analysis): 1 of 125 slip surfaces F of S Rank (Query): 1 of 125 slip surfaces Exit: (22, 100) ft Entry: (36, 105) ft Radius: 11.857063 ft Center: (25.892937, 111.19978) ft Slip Slices Base Normal Stress I Frictional Strength N Cohesive Strength 12.119328 X (ft) Y (ft) PWP 27.184533 0 63.246538 (psf) Slice 1 22.230769 99.925043 0 Slice 2 22.692308 99.785378 0 Slice 3 23.153846 99.665867 0 slice 4 23.615385 99.565886 0 Slice 5 24.076923 99.484935 0 Base Normal Stress I Frictional Strength N Cohesive Strength 12.119328 8.8052068 0 37.416299 27.184533 0 63.246538 45.951299 0 88.391265 64.220013 0 111.13044 80.740987 0 file:///C:IU serslterry.dunn/D esktop/4937.01 %20slopew/612%20north,%20proposed,%20seism ic.html 314 6/6/2017 file:///C:/Users/terry.dunn/Desktop/4937.01 %20slopew/612%20north,%20proposed,%20seism ic.htm I 4/4 7th Ave S Short Plat Slice 6 24.538462 99.422621 0 129.62575 94.178621 0 Slice 7 25 99.378649 0 142.30743 103.3924 0 Slice 8 25.461538 ,wm 99.352814 0�®. � 148.17432._w. 107. ....,. � 65494 0...... Slice 925.923077 99_.344997 0 146.94742 106.76355 0 Slicem .�..., ,. ... ®.. ,,. _., ._ . ...... ....... .. .......o,,, �. ��....,......... 26.384615 99.3551..m 63 0 139.06117 101.03386 0 10 Slice 26.846154 99.383359 0 125.5185 91.194525 0 11 Slice 1.2..ce ... ''^27.307692 99.429713 0 107.66372 �78.222269.....mm..� ... Om. .... _.. s.. .....m..� . � � Slice s � � � ...................... �....,..... 27.769231 99.494442 0 86.935825 63.162574�m...�_ 0 13 Slice 28.223234 99.576187 0 517.26596 375.81572 0 14 Slice 28.669703 99.674726 0 467.41374 339.59596 0 15 e . _ ... .. .. Slice ,n. ..,0.... _... ...., 29.116172 99.791582 418.22235 303.85632��� 0 16 Slice 29.56264 99.927327 0 371.27935 269.75023 0 17 .................. ... Slice ................... .. � 29.892937 ...�. 100.03837 s ..._.. 0 488.58664 846.25689 0�� 18 Slice 0 30 222222 100.16391 255.35078 185. 5232 0 19 Slice _..... _....._w�.._ 30.666667 100.34885 0 238.26568 173.11015 0 20 Slice .....100.55556...0 ,n...222.40006e. .. .E�._�� _.,�. _ ..........._. ®..,n.r.�.., 31.111111 161.5831 0 21 Slice . _ e..�. �� .....� �....... ........... .... �........................... .aw 31.555556 100.78533....v 0..�...w... 207.7986.... 4 150.97455 0 22 2S3Ce 101.03973 0 194.35048 141.20389 0 .. __._. Sli .m...w.. ._.._.. �. mw �.. � . A................ .e..p.. .. .._. -------- 32.444444 10...� 1.32068 1.32068 0 181.83016 132.10735 0 24Ce _ Slice 1_ �.u.. u" - . -.... ._ .m. �,... 1-11-11, -.111-11_1_11_1 �. _11. . �, 32.888889 101.6305. 1 0 169.92257 123.45598 0 25 ...... ,�...... ,� .... ..... e. ...... Slice _...33.333333 _..., _ n ...... � . ®.... e.......... � �. � 101.9721.. 6 0 158.23375 114.96355 0 26 Zlce 33.777778 102.34932 0 146.28883 106.28506 0 .... ......M.. , ............. ......._ ... .............. Slice... 34.25 102.7959 0 124.18847 90.228201 0 28 ®...............34.75 Slice � w..91.22.,. ,�.. .._... ............ �.�,,. �..,.... .�....... �..�.u.. .,.. 103.32572 0......... 4536 66.278505 0 29 Slice 35.25 103.92865 0 191.48969 139.12541 0 30 . ... . m ....... ..,_............. .... .... . .... ......... .., 35.75 104.62518 0 149.05979 108.2982 8 0 31SliCe file:///C:/Users/terry.dunn/Desktop/4937.01 %20slopew/612%20north,%20proposed,%20seism ic.htm I 4/4 Report Distribution ES -4937.01 EMAIL ONLY Select Homes, Inc. 16531 -13th Avenue West, Suite A107 Lynnwood, Washington 98037 Attention: Ms. Kayla Clark EMAIL ONLY RAM Engineering, Inc. 16831 — Ie Avenue West, Suite A108 Lynnwood, Washington 98037 Attention: Mr. Rob Long Earth Solutions NW, LLC