The URL can be used to link to this page

BLD2018-1622 Approved WC3 Hwy 99 Edmonds - Geo ReportGEOTECHNICAL ENGINEERING REPORT Proposed Edmonds Apartments 23326 Highway 99 Edmonds, Washington Project No. 1948.02 November 20, 2018 Prepared for: Goodman Real Estate PLAN REVIEW ACCEPTANCE FOR COMPLIANCE WITH THE APPLICABLE CONSTRUCTION CODES IDENTIFIED BELOW. BUILDING [@ STRUCTURAL MECHANICAL PLUMBING ELECTRICAL ENERGY ACCESSIBILITY FIRE PLAN REVIEW ACCEPTANCE OF DOCUMENTS DOES NOT AUTHORIZE CONSTRUCTION TO PROCEED IN VIOLATION OF ANY FEDERAL, STATE, OR LOCAL REGULATIONS. BY: DATE: 02/03/2020 WEST COAS1'CODE CONSULTANTS, INC ; Prepared by: Zipper Geo Associates, LLC Geotechnical and Environmental Consultants 19019 36th Avenue West, Suite E Lynnwood, WA 9803 Zipp Geo G ssional Consultants Project No. 1948.02 November 20, 2018 Goodman Real Estate 2801 Alaska Way, #310 Seattle, WA 98121 Attention: Mr. Tim Dickerson Subject: Geotechnical Engineering Report Proposed Edmonds Apartments 23326 Highway 99 Edmonds, Washington Dear Dickerson, In accordance with your request and written authorization, Zipper Geo Associates, LLC (ZGA) has completed the subsurface explorations and geotechnical engineering report for the proposed Edmonds Apartments project. This report presents the findings of the subsurface exploration and geotechnical recommendations for the project. Our work was completed in general accordance with our Proposal for Geotechnical Services (Proposal No. P1948.01) dated October 15, 2018. Written authorization to proceed was provided you on January 2, 2018. We appreciate the opportunity to be of service to you on this project. If you have any questions concerning this report, or if we may be of further service, please contact us. r,inroral Y/ Zipper Geo Associates, ILL /70-4�� Robert A. Ross, P.E. Principal Geotechnical Er Copies: Addressee (1) Studio Meng Strazzara (1) Cary Kopczynski & Company (1) Navix Engineering (1) Eli 1901936 th Avenue West, Suite E Lynnwood, WA 98036 (425) 582-9928 TABLE OF CONTENTS Page INTRODUCTION........................................................................................................................................... I PROJECT UNDERSTANDING ..................................................................................................................... 1 SURFACE CONDITIONS ............................................................................................................................. 2 SUBSURFACE CONDITIONS ...................................................................................................................... 2 SoilConditions ................................................................................................................................................. 2 GroundwaterConditions ................................................................................................................................. 3 Summary of Laboratory Testing ...................................................................................................................... 3 CONCLUSIONS AND RECOMMENDATIONS ............................................................................................ 4 General.......................................................................................................................................................... 4 Geologically Hazardous Ares ........................................................................................................................... 4 Seismic Design Considerations ........................................................................................................................ 4 SitePreparation ............................................................................................................................................... 6 Structural Fill Materials and Preparation ........................................................................................................ 7 UndergroundUtilities .................................................................................................................................... 10 Temporary and Permanent Slopes ................................................................................................................ 11 TemporaryShoring ........................................................................................................................................ 12 Temporary Shoring Monitoring ..................................................................................................................... 13 BuildingFoundations ..................................................................................................................................... 14 Permanent Foundation Walls ........................................................................................................................ 15 Stormwater Detention Vault ......................................................................................................................... 16 Stormwater Infiltration Feasibility ................................................................................................................ 16 On -Grade Concrete Slabs .............................................................................................................................. 17 Permanent Drainage Considerations ............................................................................................................ 18 CLOSURE................................................................................................................................................... 18 FIGURES Figure 1 — Site and Exploration Plan Figure 2 — Lateral Earth Pressures APPENDICES Appendix A —Subsurface Exploration Procedures and Logs Appendix B — Laboratory Testing Procedures and Results GEOTECHNICAL ENGINEERING REPORT PROPOSED EDMONDS APARTMENTS 23326 HIGHWAY 99 EDMONDS, WASHINGTON Project No. 1948.02 November 20, 2018 INTRODUCTION This report documents the surface and subsurface conditions encountered at the site and our geotechnical engineering recommendations for the proposed Edmonds Apartments project. Our geotechnical engineering scope of services for the project included a literature review, site reconnaissance, subsurface exploration, laboratory testing, geotechnical engineering analysis, and preparation of this report. The observations and conclusions summarized herein are based in part upon conditions observed in our subsurface explorations, site observations, and proposed project plans at the time this report was prepared. In the event that site conditions or proposed plans change, it may be necessary to modify the conclusions and recommendations presented in this report. This report is an instrument of service and has been prepared in general accordance with locally accepted geotechnical engineering practice. This report has been prepared for the exclusive use of Goodman Real Estate, and its agents, for specific application to the subject property and stated purpose. PROJECT UNDERSTANDING Based on our review of progress drawings provided by the project architect (Studio Meng Strazzara) and the project civil engineer (Navix Engineering), we understand the project will consist of design and construction of a new multi -story apartment building on a 1.4 acre property located at 23326 Highway 99 in Edmonds, Washington. The lower two levels of the building will be utilized mostly for vehicular parking while the upper levels will contain living space. Finished floor elevations of the lower -most level are currently planned at about 405.5 to 409.75 feet. The building will generally daylight to the east and be buried to the west. Grading for the building is expected to consist mostly of cuts ranging from a minimum of about 1 to 2 feet near the northeast property corner to a maximum estimated depth of about 23 feet along the west property boundary. Stormwater control for the project will occur through an underground detention vault located below the lower parking level in the northeast portion of the building. The bottom elevation of the vault is currently proposed at elevation 402 feet. The project will also include related site improvements including relocation of existing underground utilities, new underground utilities, and frontage improvements along the east side of the site abutting Highway 99. Existing topography and a plan view of the proposed building is shown on the attached Figure 1, Site and Exploration Plan. Page 1 ZipperGeo SURFACE CONDITIONS Proposed Edmonds Apartments Project No. 1948.02 November 20, 2018 The project site consists of a 1.4 acre, roughly trapezoidal -shaped, raw land site located 23326 Highway 99 in Edmonds, Washington. The site is bordered to the north by developed commercial property; to the south by 234 th Street SW; to the east by Highway 99; and to the west by a developed multi -family site. The site is undeveloped with the exception of existing underground utilities including sanitary and storm sewer piping. Topographically, the site generally occurs as an east -facing hillside. The site generally slopes gently to moderately downward to the east. A short (approximately 10 feet tall) steep slope is located along the south half of the west property boundary. This slope descends from about elevation 430 to 420 at an angle of about 23 degrees (43 percent grade). Remaining slopes on the property are generally inclined down to the east at about 10 to 17 percent grade. Total vertical relief from the west to east property boundaries is about 20 feet. Ground cover and vegetation across a majority of the site consists dense deciduous brush and moderately dense deciduous and coniferous trees. No springs or groundwater seepage were observed on the property at the time our subsurface explorations were completed. The site along with the proposed building location are shown on the attached Site and Exploration Plan, Figure 1. SUBSURFACE CONDITIONS Mapped Geology We reviewed published geologic mapping of the site vicinity through the Washington State Department of Natural Resource's web -based mapping application Washington Geologic Information Portal (https://geologyportal.dnr.wa.gov/). The published mapping indicates the site is underlain by Vashon Till. The mapping describes Vashon Till as a nonsorted mixture of clay, silt, sand, pebbles, cobbles, and boulders, all in variable amounts. The mapping further describes the Till as " It typically is hard lodgement till and often is referred to as "hardpan." The "hardpan" is largely a result of compaction caused by the great weight of the overriding ice, hundreds of meters thick." Soil Conservation Service Hydrologic Soil Group Classification We reviewed Soil Conservation Service (SCS) mapping of the site vicinity through USDA NRCS's Web Soil Survey application (https://websoilsurvey.sc.egov.usda.gov/App/WebSoilSurvey.aspx). The mapping indicates the site is underlain by Alderwood-Urban Land Complex soils. Soil Conditions Soil conditions at the site were evaluated through the completion of 5 geotechnical test borings (13-1 to 13- 5). The borings were advanced to a depths ranging from about 21 to 39 feet below existing site grades. The approximate boring locations are shown on the attached Site and Exploration Plan, Figure 1. Soils were visually classified in general accordance with the Unified Soil Classification System. Descriptive logs of the subsurface explorations and the procedures utilized in the subsurface exploration program are presented in Appendix A. A generalized description of soil conditions encountered in the borings is Page 2 ZipperGeo Proposed Edmonds Apartments Project No. 1948.02 November 20, 2018 presented below. Detailed descriptions of soils encountered are provided on the descriptive logs in Appendix A. Surficial soils conditions observed in the borings generally consisted of about 7 to 9 inches of forest cluff and topsoil. Below the forest cluff and topsoil, soil conditions observed in borings B-1, B-4, and B-5 generally consisted of about 5 to 7 feet of loose to medium dense, silty sand with variable gravel content interpreted as weathered glacial till. Below the weathered glacial till, these borings encountered dense to very dense, silty sand with variable gravel content interpreted as glacial till to the completion depths of about 21 to 30 feet below existing site grades. Drilling action in these borings indicated localized cobbles and boulders may be present within the very dense glacial till unit. Below the forest cluff and topsoil, soil conditions observed in borings B-2 and B-3 generally consisted of about 5 to 12 feet of loose to dense, silty sand with variable gravel content interpreted to be fill soils. Below the fill soils, these borings encountered dense to very dense, silty sand with variable gravel content interpreted to be glacial till to the completion depths of about 31 to 40 feet below existing site grade. Drilling action in these borings indicated localized cobbles and boulders may be present within the very dense glacial till unit. Groundwater Conditions Groundwater seepage was not observed in any of the borings completed as part of our work. Perched groundwater may develop at the contact between the upper medium dense soils and lower dense to very dense soils during the wetter months of the year. Fluctuations in groundwater levels will likely occur due to seasonal variations in the amount of rainfall, runoff and other factors not evident at the time the explorations were performed. Therefore, groundwater levels during construction or at other times in the life of the structure may be higher than indicated on the logs. The possibility of groundwater level fluctuations should be considered when developing the design and construction plans for the project. Summary of Laboratory Testing Laboratory testing was completed on select soil samples obtained from the explorations. Moisture content testing of soil samples obtained within the upper 17 feet of existing site grade ranged from about 5 to 20 percent with an average of about 10 percent. Grain size analysis were completed on select samples obtained from the borings. The grain size analysis indicated fines contents (silt and clay sized soil particles) as follows: Boring Number Sample Number Sample Depth (feet) Fines Content B-2 S-2 5 41% B-2 S-4 15 15% B-3 S-2 5 24% B-4 S-3 10 32% B-5 Composite S-4, S-5, & S-6 12.5 to 17.5 33% Page 3 ZipperGeo CONCLUSIONS AND RECOMMENDATIONS General Proposed Edmonds Apartments Project No. 1948.02 November 20, 2018 Based on our subsurface exploration program and associated research, we conclude that the proposed development is geotechnically feasible, contingent on proper design and construction practices and implementation of the recommendations presented in this report. Our recommendations are presented in the following sections. The recommendations contained in this report are based upon the results of field and laboratory testing (which are presented in Appendices A and B), engineering analyses, and our current understanding of the proposed project. ASTM and Washington State Department of Transportation (WSDOT) specification codes cited herein respectively refer to the current manual published by the American Society for Testing & Materials and the current edition of the WSDOT Standard Specifications for Road, Bridge, and Municipal Construction, (M41-10). Geologically Hazardous Ares As part of our services, we evaluated the presence of regulated geologically hazardous areas (GHAs) at the site. Chapter 23.80 of the Edmonds Municipal Code (the Code) designates GHAs as Erosion Hazard, Landslide Hazard, and Seismic Hazard. The reader is referred to the Code for definitions of GHAs. Based on soil conditions observed in our explorations and site slopes, the site is underlain by Alderwood soils with areas of slopes ranging from 10 to 43 percent grade, and therefore contains Erosion Hazard GHAs. For mitigation of erosion hazards at the site, we recommend the following: • A proper temporary erosion and sediment control plan should be prepared in accordance with local standards by the project civil engineer. • All areas disturbed by construction and not permanently covered with hard surfaces should be adequately stabilized through permanent landscaping. • Design and construct the project in accordance with the recommendations presented in this report. Provided that the above-recorn mended mitigation measures are implemented, it is our opinion that the potential for erosion and off -site sediment transport will be minimized. Based on soil conditions observed in our explorations and existing site topography, it is our opinion that no areas on the site meet the Code -defined criteria for a Landslide Hazard or Seismic Hazard Area. Seismic Design Considerations The tectonic setting of western Washington is dominated by the Cascadia Subduction Zone formed by the Juan cle Fuca plate subducting beneath the North American Plate. This setting leads to intraplate, crustal, Page 4 ZipperGeo Proposed Edmonds Apartments Project No. 1948.02 November 20, 2018 and interplate earthquake sources. Seismic hazards relate to risks of injury to people and damage to property resulting from these three principle earthquake sources. The seismic performance of the development was evaluated relative to seismic hazards resulting from ground shaking associated with a design seismic event with a 2,475 year return period determined in accordance with the 2015 International Building Code (IBC). Conformance to the above criteria for seismic excitation does not constitute any kind of guarantee or assurance that significant structural damage or ground failure will not occur if a maximum level earthquake occurs. The primary goal of the IBC seismic design procedure is to protect life and not to avoid all damage, since such design may be economically prohibitive. Following a major earthquake, a building may be damaged beyond repair, yet not collapse. IBC Seismic Design Parameters: Based on site location and soil conditions, the values provided below are recommended for seismic design. The values provided below are based on the 2015 IBC as the building code reference document. Description Value 2015 IBC Site Classification ' C 1 Ss Spectral Acceleration for a Short Period 1.263 g (Site Class B) S1 Spectral Acceleration for a 1-Second Period 0.493 g (site Class B) Sms Maximum considered spectral response 1.263 g (Site Class C) acceleration for a Short Period Smi Maximum considered spectral response 0.645 g (Site Class C) acceleration for a 1-Second Period SDs Five -percent damped design spectral response 0.852 g (Site Class C) acceleration for a Short Period SD1 Five -percent damped design spectral response 0.430 g (Site Class C) acceleration for a 1-Second Period 1. In general accordance with the 2015 International Building Code, Table 1613.5.2. IBC Site Class is based on the average characteristics of the upper 100 feet of the subsurface profile. 2. The borings completed for this study extended to a maximum depth of 40 feet below grade. ZGA therefore determined the Site Class assuming that similar density soils extend to 100 feet as suggested by published geologic maps for the project area. Ground Surface Rupture: Based on our review of the USGS Quaternary age fault database for Washington State, a strand of the Southern Whidbey Island Fault Zone is located approximately 1500 feet northeast of the project site. As the fault does not appear to cross the site, it is our opinion that the risk of ground surface rupture at the site is low. Page 5 ZipperGeo Proposed Edmonds Apartments Project No. 1948.02 November 20, 2018 Landsliding: Based on subsurface soil and groundwater conditions observed in our explorations and the gently to moderately sloping topography of the site and surrounding vicinity, it is our opinion that the risk of earthquake -induced landslicling is low. Soil Liquefaction: Liquefaction is a phenomenon wherein cohesionless soils below the groundwater table build up excess pore water pressures during earthquake loading. Liquefaction typically occurs in loose, cohesionless soils, but may occur in denser soils if the ground shaking is sufficiently strong. The potential hazardous impacts of liquefaction include liquefaction -induced settlement and lateral spreading. Soil conditions observed in our explorations generally consisted of dense to very dense, glacially overridden soils with no groundwater. The glacially overridden soils observed in our explorations are not susceptible to liquefaction. Site Preparation Erosion Control Measures: Stripped surfaces and soil stockpiles are typically a source of runoff sediments. We recommend that silt fences, berms, and/or swales be installed around the clownslope side of stripped areas and stockpiles in order to capture runoff water and sediment. If earthwork occurs during wet weather, we recommend that all stripped surfaces be covered with straw to reduce runoff erosion, whereas soil stockpiles should be protected with anchored plastic sheeting. Temporary Drainage: Stripping, excavation, grading, and subgrade preparation should be performed in a manner and sequence that will provide drainage at all times and provide proper control of erosion. The site should be graded to prevent water from poncling in construction areas and/or flowing into and/or over excavations. Exposed grades should be crowned, sloped, and smooth -drum rolled at the end of each day to facilitate drainage if inclement weather is forecasted. Accumulated water must be removed from subgrades and work areas immediately and prior to performing further work in the area. Equipment access may be limited and the amount of soil rendered unfit for use as structural fill may be greatly increased if drainage efforts are not accomplished in a timely manner. Clearing, Stripping, and Existing Utility Abandonment: Once TESC measures are installed, we expect site preparation to continue with clearing and grubbing brush and trees, stripping of organic rich topsoil, an abandonment of existing underground utilities. We recommend all tree stumps and roots larger than Y2 inch in diameter be cleared and grubbed from the areas planned for improvement. Based on our explorations, stripping depths to remove topsoil is estimated to range from about 7 to 10 inches. Stripping depths may be greater near trees and brush to fully remove root systems. All clearing and stripping debris should be wasted off site or, if approved, used for topsoil in landscape areas. For utility abandonment, we recommend all existing underground utilities be completely removed and wasted off site. Excavations for utility abandonment should be backfilled with compacted structural fill placed in accordance with this report. Alternatively, existing underground utility piping could be abandoned in -place by fully grouting the conduits. Page 6 ZipperGeo Proposed Edmonds Apartments Project No. 1948.02 November 20, 2018 Subgrade Preparation: Once site preparation is complete, all areas that are at design subgrade elevation or areas that will receive new structural fill should be moisture conditioned to a moisture content within plus or minus two percent of optimum moisture content for compaction. The subgrade should then be compacted to a firm and unyielding condition. The existing site soils consist of silty sand at or somewhat above optimum moisture content for compaction. During wet weather, achieving a moisture content adequate for compaction will be impossible. Therefore, we recommend subgrade preparation and earthwork in general, be completed during drier periods of the year when the soil moisture content can be control;ed by aeration and drying. If earthwork or construction activities take place during extended periods of wet weather, or if the in situ moisture conditions are elevated above the optimum moisture content, the soils will become unstable and not compactable. In the event the exposed subgrade becomes unstable ' yielding, or unable to be compacted due to high moisture conditions, we recommend that the materials be removed to a sufficient depth in order to develop stable subgrade soils that can be compacted to the minimum recommended levels. The severity of construction problems will be dependent, in part, on the precautions that are taken by the contractor to protect the subgrade soils. Once compacted, subgrades should be evaluated through density testing and proof rolling with a loaded dump truck or heavy rubber -tired construction equipment weighing at least 20 tons to assess the subgrade adequacy and to detect soft and/or yielding soils. In the event that compaction fails to meet the specified criteria, the upper 12 inches of subgrade should be scarified and moisture conditioned as necessary to obtain at least 95 percent of the maximum laboratory density (per ASTIVI D1557). Those soils which are soft, yielding, or unable to be compacted to the specified criteria should be over -excavated and replaced with suitable material as recommended in the Structural Fill section of this report. As an alternate to subgrade compaction during wet site conditions or wet weather, the upper 12 inches of subgrade should be overexcavated to a firm, non -yielding and undisturbed condition and backfilled with compacted imported structural fill consisting of free -draining Gravel Borrow or crushed rock. Freezing Conditions: If earthwork takes place during freezing conditions, all exposed subgrades should be allowed to thaw and then be compacted prior to placing subsequent lifts of structural fill. Alternatively, the frozen material could be stripped from the subgrade to expose unfrozen soil prior to placing subsequent lifts of fill or foundation components. The frozen soil should not be reused as structural fill until allowed to thaw and adjusted to the proper moisture content, which may not be possible during winter months. Structural Fill Materials and Preparation Structural fill includes any material placed below foundations and pavement sections, within utility trenches, to construct embankments, and behind retaining walls. Prior to the placement of structural fill, all surfaces to receive fill should be prepared as previously recommended in the Site Preparation section of this report. Page 7 ZipperGeo Proposed Edmonds Apartments Project No. 1948.02 November 20, 2018 Laboratory Testing: Representative samples of on -site and imported soils to be used as structural fill should be submitted for laboratory testing at least 4 days in advance of its intended use in order to complete the necessary Proctor tests. Reuse of Site Soils as Structural Fill: Mass grading for the building is expected to consist mostly of cuts with the excavation spoils hauled off site. However, we expect the reuse of site soils as structural fill will be desirable for underground utilities and for backfill around the proposed stormwater detention vault. The suitability for reuse of site soils as structural fill depends on the composition and moisture content of the soil. Soils encountered in excavations at the site are expected to consist of sands with a significant fines content (1S to over 30 percent). As the amount of fines increases, the soil becomes increasingly sensitive to small changes in moisture content. Soils containing more than about 5 percent fines cannot be consistently compacted to the appropriate levels when the moisture content is more than approximately 2 percent above or below the optimum moisture content (per ASTM D1557). Optimum moisture content is that moisture content which results in the greatest compacted dry density with a specified compactive effort. Laboratory testing of select soil samples indicates the in -place moisture content of site soils ranges from about 5 to 20 percent with an average of about 10 percent. Optimum moisture content of site soils is estimated at about 6 to 10 percent. Therefore, site soils appear at or slightly above optimum moisture content for compaction. Site soils will only be suitable for reuse as structural fill during dry weather. During wet weather, site soil will quickly become too wet for reuse as structural fill. During wet weather, the project team and bidding contractors should expect that site soils will not be suitable for reuse as structural fill and imported fill with little to no fines content will be required. We recommend that site soils used as structural fill have less than 4 percent organics by weight and have no woody debris greater than Y2 inch in diameter. We recommend that all pieces of organic material greater than Y2 inch in diameter be picked out of the fill before it is compacted. Any organic -rich soil derived from earthwork activities should be utilized in landscape areas or wasted off site. Imported Structural Fill: If backfilling of underground utilities and the stormwater detention vault occurs during wet weather, imported structural fill may be required. The appropriate type of imported structural fill will depend on weather conditions. During extended periods of dry weather, we recommend imported fill, at a minimum, meet the requirements of Common Borrow as specified in Section 9-03.14(3) of the most current version of the Washington State Department of Transportation, Standard Specifications for Road, Bridge, and Municipal Construction (WSDOT Standard Specifications). During wet weather, higher - quality structural fill might be required, as Common Borrow may contain sufficient fines to be moisture sensitive. During wet weather we recommend that imported structural fill meet the requirements of Gravel Borrow as specified in Section 9-03.14(l) of the WSDOT Standard Specifications. Prior to importing Page 8 ZipperGeo Proposed Edmonds Apartments Project No. 1948.02 November 20, 2018 structural fill for general use in raising site grades, we recommend we be provided a sample of the material to evaluate its suitability for use as structural fill. Retaining Wall Backfill: Cast -in -place concrete foundation retaining walls should include a drainage fill zone extending at least 2 feet back from the back face of wall for the entire wall height. The drainage fill should meet the requirements of Gravel Backfill for Walls as specified in Section 9-03.12(2) of the WSDOT Standard Specifications. Compaction Criteria: Our recommendations for soil compaction are summarized in the following table. Structural fill for roadways and utility trenches in municipal rights -of -way should be placed and compacted in accordance with the jurisdiction codes and standards. We recommend that a geotechnical engineer be present during grading so that an adequate number of density tests may be conducted as structural fill placement occurs. In this way, the adequacy of the earthwork may be evaluated as it proceeds. RECOMMENDED SOIL COMPACTION LEVELS Location Minimum Percent Compaction* All fill below building floor slabs and foundations 95 Upper 2 feet of fill below pavements 95 Pavement fill below 2 feet 92 Retaining wall backfill less 3 feet from back of wall face 92** Upper 2 feet of utility trench backfill 95 Utility trenches below 2 feet 92 Landscape Areas 90 * ASTM D1557 Modified Proctor Maximum Dry Density "Care must be taken not to over -compact retaining wall backfill as over -compaction can induce stresses in excess of design stresses. Moisture Content: Structural fill should be placed at a moisture content within plus or minus two percent of optimum moisture content as determined by the ASTIVI D-1557 test method (modified proctor). Imported structural fill should be delivered to the site at the recommended moisture content for compaction. Structural fill with a moisture content greater than two percent above optimum should be moisture conditioned by windrowing and drying or wasted off site. Structural fill with a moisture content less than two percent below optimum should be blended with water to achieve the recommended moisture content. Fill Placement: Structural fill should be placed in horizontal lifts with a loose lift thickness appropriate for the material and energy of the compaction equipment used. If lift loose lift thickness greater than 12 inches are desired, the contractor should be required to demonstrate that the combination of fill material and compaction equipment can compact the entire lift thickness to the specified levels. Each lift of fill Page 9 ZipperGeo Proposed Edmonds Apartments Project No. 1948.02 November 20, 2018 should be compacted to the minimum levels recommended above based on the maximum laboratory dry density as determined by the ASTM D1557 Modified Proctor Compaction Test. Underground Utilities We recommend that utility trenching conform to all applicable federal, state, and local regulations, such as OSHA and WISHA, for open excavations. Trench excavation safety guidelines are presented in WAC Chapter 296-155 and WISHA RCW Chapter 49.17. Utility Subgrade Preparation: We recommend that all utility subgrades be firm and unyielding and free of all soils that are loose, disturbed, or pumping. Such soils should be removed and replaced, if necessary. All structural fill used to replace over -excavated soils should be compacted as recommended in the Structural Fill section of this report. If utility foundation soils are soft, we recommend that they be over - excavated 12 inches and replaced with crushed rock. Structures such as manholes and catch basins which extend into soft soils should be underlain by at least 12 inches of crushed gravel fill compacted to at least 90 percent of the modified Proctor maximum dry density. This granular material could consist of crushed rock, quarry spalls, or coarse crushed concrete. Alternatively, quarry spalls or pea gravel could be used until above the water level. It may be necessary to place a geotextile fabric over the native subgrade soils if they are too soft, to provide a separation between the bedding and subgrade soils. Bedding: We recommend that a minimum of 4 inches of bedding material be placed above and below all utilities or in general accordance with the utility manufacturer's recommendations and local ordinances. We recommend that pipe bedding consist of Gravel Backfill for Pipe Zone Bedding as specified in Section 9-03.12(3) of the WSDOT Standard Specifications. All trenches should be wide enough to allow for compaction around the haunches of the pipe, or material such as pea gravel should be used below the spring line of the pipes to eliminate the need for mechanical compaction in this portion of the trenches. If water is encountered in the excavations, it should be removed prior to fill placement. Trench Backfill: Materials, placement, and compaction of utility trench backfill should be in accordance with the recommendations presented in the StructuralFill section of this report. In our opinion, the initial lift thickness should not exceed I foot unless recommended by the manufacturer to protect utilities from damage by compacting equipment. Light, hand operated compaction equipment may be utilized directly above utilities if damage resulting from heavier compaction equipment is of concern. Underground Utility Construction Sequencing: Based on our review of plans provided by the project civil engineer, new underground utilities are proposed along the outside of the building perimeter on the west side of the site. As discussed subsequently, temporary shoring will likely be required to construct the building. Installation of these utilities may conflict with temporary shoring elements. Additionally, access to the utility alignments could be difficult after temporary shoring is constructed. Construction Page 10 ZipperGeo Proposed Edmonds Apartments Project No. 1948.02 November 20, 2018 sequencing for construction of underground utilities and other aspects of the project should be thoroughly evaluated by the project team to identify and avoid potential conflicts. Temporary and Permanent Slopes Temporary excavation slope stability is a function of many factors, including: 0 The presence and abundance of groundwater; • The type and density of the various soil strata; • The depth of cut; • Surcharge loadings adjacent to the excavation; and • The length of time the excavation remains open. As the cut is deepened, or as the length of time an excavation is open, the likelihood of bank failure increases; therefore, maintenance of safe slopes and worker safety should remain the responsibility of the contractor, who is present at the site, able to observe changes in the soil conditions, and monitor the performance of the excavation. It is exceedingly difficult under the variable circumstances to pre -establish a safe and "maintenance -free" temporary cut slope angle. Therefore, it should be the responsibility of the contractor to maintain safe temporary slope configurations since the contractor is continuously at the job site, able to observe the nature and condition of the cut slopes, and able to monitor the subsurface materials and groundwater conditions encountered. Unsupported vertical slopes or cuts deeper than 4 feet are not recommended if worker access is necessary. The cuts should be adequately sloped, shored, or supported to prevent injury to personnel from local sloughing and spalling. The excavation should conform to applicable Federal, State, and Local regulations. According to Chapter 296-155, Part N of the Washington Administrative Code (WAC), the contractor should make a determination of excavation side slopes based on classification of soils encountered at the time of excavation. For planning purposes, we recommend temporary excavations within the upper 10 feet of existing site grades be planned no steeper than 1.5H:1V (horizontal to vertical). Temporary excavations completed in the very dense glacial till soils observed in our explorations (typically observed below 10 feet from existing site grades) should be planned not steeper than 0.75H:IV. Temporary cuts may need to be constructed at flatter angles based upon the soil moisture and groundwater conditions at the time of construction. Adjustments to the slope angles should be determined by the contractor at that time. Temporary excavations that extend below the groundwater table will not be adequately stable unless clewatered. Groundwater levels should be maintained a minimum of two feet below the bottom of temporary excavations. We recommend that all permanent cut or fill slopes (excluding stormwater ponds) constructed in native soils or with imported structural fill be designed at a 2H:1V (Horizontal:Vertical) inclination or flatter. All Page 11 ZipperGeo Proposed Edmonds Apartments Project No. 1948.02 November 20, 2018 permanent cut and fill slopes should be adequately protected from erosion both temporarily and permanently. We do not expect stormwater ponds for this project. If the slopes are exposed to prolonged rainfall before vegetation becomes established, the surficial soils will be prone to erosion and possible shallow sloughing. We recommend covering permanent slopes with a rolled erosion protection material, such as composite straw or coir matting or Curlex 11, if vegetation has not been established by the regional wet season (typically November through May). Temporary Shoring Based on our analysis, it appears sloped temporary excavations to construct the building along the north, west, and portions of the south property line are not feasible as they would extend beyond the property line. As such, it appears that temporary shoring will be required. In order to determine the limits of required temporary shoring, we recommend the project civil engineer develop a temporary excavation grading plan using the planning criteria for temporary cut slope inclinations provided above in the Temporary and Permanent Slopes section of this report. For the expected shoring heights, we have identified two alternatives for temporary shoring: 1.) anchored and cantilever soldier pile retaining walls or 2.) soil nail retaining walls. Soil nail U—pp-bdCLA—. walls are typically more economical as compared to anchored soldier pile SEep 1. E��Ml� Irfial Lift SNp 2. Drid Nag H* retaining walls. Based on subsurface soil and groundwater conditions, it is our opinion soil nailing is feasible for temporary shoring. The process of soil nailing consists of making short (typically 5 feet or less) vertical cuts, installing horizontal elements (soil nails) extending into the cut, and then placing a thin layer (typically 4 inches) of reinforced shotcrete (pneumatically placed concrete) on the soil cut face. Soil nails are typically installed at horizontal and vertical spacings of about 4 to 6 feet on 51,,, O-n Cul Stop 3. r;M1 aM Gfoul NO (Irp*dE* 64np L)ralm instaft9don) ----------- 2 ------------ 2 ------------ Flul ck� - 4 SWO 5, comtlucuon 0! SubSKUON LRVO� E]rjin SIM 4, PIRGA InVpl FWmj ?.InrhiClp� Ghab=&.P. PeiryruMTOM 9�rng �16W.Wa�hef aiA H&A NuL tigUllubW1 Stem 0. Place F-A Faciftg �1miudes6dIldir-A 01 FW Cvwn) center. The length of soil nails is typically about 0.7 times the wall height and installed at about 15 to 20 degrees from horizontal. The process is repeated until the bottom of the excavation is reached. Soil nail walls are most favorable in soils that show a significant standup time when cut vertical. However, alternative methods can be utilized Page 12 ZipperGeo Proposed Edmonds Apartments Project No. 1948.02 November 20, 2018 in less -stable soils such as stabilization berms, vertical elements, or shotcrete flash coating. The typical sequence of soil nailing is shown in the figure above. It should be noted that soil nails may extend beyond property lines therefore requiring temporary underground construction easements from adjacent property owners. Additionally, soil nails may conflict with existing or proposed underground utilities. These conflicts should be evaluated by the shoring designer. For design of soil nail shoring walls, we recommend the following design parameters. The shoring designer should refer to the boring logs provided in Appendix A for soil unit depth limits. Soil Unit Moist Soil Soil Friction Angle Soil Cohesion Ultimate Unit Weight (degrees) (psf) Ground/Grout Bond (pcf) (kips/ft)* Fill & Weathered Till 125 34 0 6 Till 135 40 500 10 *Assumes 6-inch minimum drill hole diameter Design of soil nail walls should be completed in accordance with the methodologies presented in the Federal Highway Administration Report Number FHWA-IF-03-017, Geotechnical Engineering Circular No. 7, Soil Nail Walls (allowable stress design). Construction of soil nail walls should be in accordance with Section 6-15 of the 2015 Washington State Department of Transportation Standard Specifications for Road, Bridge and Municipal Construction. We recommend that a minimum of two sacrificial, 200 percent verification tests be performed in each soil type to be nailed in order to evaluate the ultimate soil friction capacity and the load deformation performance of the soil nail. Verification testing should be accomplished as soon as each soil type is encountered and prior to installation of production nails. The location of the verification tests should be selected by the contractor and approved by the engineer of record. The drilling method, hole diameter, and depth of soil nail should be identical to the production soil nails. Additionally, 5 percent of production soil nails should be proof tested to 150 percent of design load to confirm the design capacity and appropriate construction methods. Zipper Geo Associates has extensive design experience with soil nail shoring walls. We are available to provide shoring design upon request. If the project team prefers anchored and cantilever solider pile shoring, we should be consulted to provide additional recommendations. Temporary Shoring Monitoring Any time an excavation is made below the level of existing buildings, utilities, or other structures, there is risk of damage even if a well -designed shoring system has been planned. Therefore, we recommend that Page 13 ZipperGeo Proposed Edmonds Apartments Project No. 1948.02 November 20, 2018 a monitoring program be conducted on adjacent facilities and structures. The monitoring program should include measurements of the horizontal and vertical movements of the adjacent structures and the shoring system itself. At least two reference lines should be established adjacent to the excavation at horizontal distances back from the excavation space of about 1/3H and H, where H is the final excavation height. Monitoring of the shoring system should include measurements of horizontal and vertical movements. If local wet areas are noted within the excavation, additional monitoring points may be recommended by ZGA. The measuring system used for shoring monitoring should have an accuracy of at least 0.01 foot. All reference points should be installed and readings taken prior to commencing the excavation. All reference points should be read prior to and during critical stages of construction. The frequency of readings will depend on the results of previous readings and the rate of construction. As a minimum, readings should be taken about once a week throughout construction until the basement walls are completed. All readings should be reviewed by ZGA. In order to limit the potential for construction damage claims on adjacent properties, we recommend the condition of existing off -site improvements be carefully documented. We recommend making a complete inspection and evaluation of pavements, structures, utilities, and other facilities located a maximum distance of two times the maximum shoring retained height. This inspection should focus on detecting any existing signs of existing damage. We recommend the observations be documented by pictures, notes, survey drawings, or other means of verification. If existing cracks are noted, consideration should be given to installing crack monitoring gauges to detect and document slight movements. Pre - construction condition assessments should be conducted in coordination with appropriate contractors, the owner, and shoring designer. Building Foundations Based on our analyses, conventional, shallow spread footings appear feasible for support of building foundation loads provided that the foundation subgrades are prepared in accordance with this report. Recommendations for shallow spread footings are provided below. General Footine Subgrade Preoaration Soils encountered at footing subgrade elevation are expected to consist of two distinct conditions. Where footings are located less than about 10 feet below existing site grades (generally in the east half of the building), soil conditions expected at footing subgrade elevations are expected to consist of medium dense to dense, weathered glacial till. Footing subgrade preparation in these areas should consist of compacting the footing subgrade to a firm and unyielding condition. Where footing subgrades are located greater than about 10 feet below existing site grades (generally in the west half of the building), soil conditions expected at footing subgrade elevation are expected to Page 14 ZipperGeo Proposed Edmonds Apartments Project No. 1948.02 November 20, 2018 consist of very dense, glacial till soils. In these areas, we do not expect any special footing subgrade preparation will be required. If wet weather is predicted, prepared footing subgrades should be protected through placement of a thin layer of controlled density fill (CDF). Shallow Foundation Allowable Bearing Pressure For footings founded less than 10 feet below existing site grade, we recommended an allowable bearing pressure of 3,000 psf. For footings founded greater than 10 feet below existing site grade, we recommend an allowable bearing pressure of 7,000 psf. A one-third increase of the bearing pressure recommended above may be used for short-term transient loads such as wind and seismic forces. Shallow Foundation Depth and Width For frost protection, the bottom of all exterior footings should bear at least 18 inches below the lowest adjacent outside grade, whereas the bottoms of interior footings should bear at least 12 inches below the surrounding slab surface level. We recommend that all continuous wall and isolated column footings be at least 12 and 24 inches wide, respectively. Lateral Resistance Resistance to lateral loads can be calculated assuming an ultimate soil passive resistance of 450 pcf equivalent fluid pressure (triangular distribution) and an ultimate base friction coefficient of 0.50. An appropriate safety factor (or load/resistance factors) should be included for calculating resistance to lateral loads. For allowable stress design, we recommend a minimum 1.5 safety factor. We recommend that passive resistance be neglected in the upper 18 inches of embedment. The above -recommended soil passive resistance assumes any structural fill used to backfill footing excavations is placed and compacted in accordance with the recommendations presented in this report. Estimated Foundation Settlements Total settlement of footings for service load conditions founded on a subgrade prepared as recommended in this report are estimated to be less than I inch. Differential settlement is estimated to be about Y2 inch or less in 40 feet. The above estimated foundation settlements should be considered preliminary. ZGA should be provided an opportunity to review foundation plans for the building to confirm or revise our estimated foundation settlements. Permanent Foundation Walls Recommended lateral earth pressures for design of permanent foundation walls are provided graphically in the attached Figure 2. Figure 2 provides recommendations for both static and seismic lateral earth pressures assuming an active condition. Lateral earth pressures were estimated in general accordance with generalized limit equilibrium (GLE) methodologies as described in Part 3 of the 2009 NEHRP Recommended Seismic Provisions for New Buildings and Other Structures (2009 NEHRP). Per Section Page 15 ZipperGeo Proposed Edmonds Apartments Project No. 1948.02 November 20, 2018 11.8.3 Commentary of the 2009 NEHRP, 2/3 of the PGArn was used for the design horizontal ground acceleration, kh. From the ASCE 7 seismic design maps web -based application, PGAm was determined to be 0.51g. Therefore a kh value of 0.34g was used. For the seismic component, limits of the seismic active earth pressure wedge were constrained to match that of the static wedge per recommendations presented in Tsai and Newman, 2014 (Wedge Size Issues On Calculating Seismically Induced Lateral Earth Pressure For Retaining Structures — An Overview And A New Simple Approach, Journal of GeoEngineering, Vol. 9, No. 2, pp. 45-53, August 2014). For lateral resistance, parameters provided above in the Building Foundations section of this report may be used. The recommendations for lateral earth pressures presented in Figure 2 for the west building line foundation wall assume that this wall will be cast neat against a temporary shoring wall. If the west building line foundation wall will be backfilled, we should be consulted for revised earth pressures. The earth pressures presented in Figure 2 assume an active earth pressure condition will prevail. If any permanent foundation walls will be braced prior to backfilling, an at -rest earth pressure condition will prevail and we should be consulted for revised earth pressures. Stormwater Detention Vault Current plans indicate an approximate 31,500 cubic foot underground detention vault will be constructed in the northeast portion of the site. The bottom elevation of the vault is currently proposed at elevation 402 feet. For lateral earth pressures, Figure 2 may be used for design of the vault. For bearing pressure and lateral resistance values, information provided above in the Building Foundations section of this report may be used. Footings for the building may impose a surcharge on the vault walls. If possible, we recommend building footings near the vault be planned such that they do not impose a surcharge on the vault walls by locating them in such a manner that a 1H:1V line projected from the bottom edge of a footing does not intersect vault walls. We should be consulted for surcharge recommendations if the footings cannot be located below this 1H:1V plane. Stormwater Infiltration Feasibility Borings B-4 and B-5 were completed in the vicinity of the proposed stormwater vault. At the proposed vault bottom elevation of 402 feet, the borings indicate site soil conditions consist of very dense glacial till (hardpan). Stormwater design in the City of Edmonds is regulated by the DOE's 2014 Stormwater Management Manual for Western Washington (2014 SWMM) and the City of Edmonds June 8, 2017 Stormwater Addendum. Appendix A of the June 2017 Edmonds Stormwater Addendum (ESA) outlines infeasibility criteria for various stormwater management BIVIPs. For infiltration systems, the ESA requires at least I foot of permeable soil from the bottom of the infiltration system to the seasonal high groundwater table or other impermeable layer. The 2014 SWIVIM defines permeable soil as "Soil materials with a sufficiently Page 16 ZipperGeo Proposed Edmonds Apartments Project No. 1948.02 November 20, 2018 rapid infiltration rate so as to greatly reduce or eliminate surface and stormwater runoff. These soils are generally classified as SCS hydrologic soil types A and B." As indicated above, SCS mapping indicates the site is underlain by the Alderwood group of soils. The 2014 SWMM classifies the Alderwood group soils as hydrologic soil group C. The 2014 SWMM defines hydrologic soil group as: "Soils having low infiltration rates when thoroughly wetted and consist chiefly of soils with a layer that impedes downward movement of water and soils with moderately fine to fine textures. These soils have a low rate of water transmission (0.05-0.15 in/hr.)." Additionally, in many areas, the 2014 SWMM generally refers to hardpan or glacial till as an impermeable layer as related to stormwater infiltration. We agree with the DOE's classification of till as an impermeable soil as related to stormwater infiltration. Additionally, the till at this site is extremely dense and contains fines contents generally in excess of 30 percent fines further supporting the generally impermeable nature of the till at this site. As such, it is our opinion that stormwater infiltration at the currently proposed vault location and elevation is infeasible due to the impermeable nature of till soils at this site. Based on proposed site grades and soils encountered in other borings, it is further our opinion that stormwater infiltration at other locations on the site is infeasible. On -Grade Concrete Slabs The following sections provide recommendations for on -grade floor slabs. Subgrade Preparation and Modulus of Subgrade Reaction Subgrades for on -grade slabs should be prepared in accordance with the Site Preparation and Structural Fill sections of this report. For slab subgrades prepared in accordance with this report, a modulus of vertical subgrade reaction of 250 pounds per cubic inch (pci) may be used for design. Capillary Break To provide a capillary break, uniform slab bearing surface, and a minimum subgrade modulus of 150 pci, we recommend the on -grade slabs be underlain by a 6-inch thick layer of compacted, granular fill contain less than 5 percent fines, based on that soil fraction passing the U.S. No. 4 sieve. A clean angular gravel such as No. 7 aggregate per WSDOT: 9-03.1(4)C could be used for this purpose. Alternative capillary break materials should be submitted to the geotechnical engineer for review and approval before use. Vapor Retarder The use of a vapor retarder should be considered beneath concrete slabs on grade that will be covered with wood, tile, carpet or other moisture sensitive or impervious coverings, or when the slab will support equipment sensitive to moisture or is otherwise considered moisture -sensitive. When conditions warrant the use of a vapor retarder, the slab designer and contractor should refer to ACI 302 and/or ACI 360 for procedures and cautions regarding the use and placement of a vapor retarder. Page 17 Proposed Edmonds Apartments Project No. 1948.02 ZipperGeo November 20, 2018 Permanent Drainage Considerations Surface Drainage Final site grades should be sloped to carry surface water away from buildings and other drainage -sensitive areas. Additionally, site grades should be designed such that concentrated runoff on softscape surfaces is avoided. Any surface runoff directed towards softscaped slopes should be collected at the top of the slope and routed to the bottom of the slope and discharged in a manner that prevents erosion. Permanent Foundation Wall Draina While groundwater was not encountered within our borings, surface water and coarse -grained zones within the Glacial Till create the potential for hydrostatic buildup behind the below -grade portions of the structure. Adequate drainage measures must be installed to collect and direct subsurface water away from subgrade walls. All backfilled walls should include a drainage aggregate zone extending a minimum of two feet from the back of wall for the full height of the wall and wide enough at the base of the wall to allow seepage to flow to the footing drain. The drainage aggregate should consist of material meeting the requirements of WSDOT 9-03.12(2), Gravel Backfill for Walls. A minimum 4-inch diameter, perforated PVC drain pipe should be provided at the base of backfilled walls to collect and direct subsurface water to an appropriate discharge point. We recommend placing a non -woven geotextile, such as Mirafi 140N, or equivalent, around the free draining backfill material. For permanent building walls cast directly against temporary soil nail shoring walls, we recommend a minimum 1-foot wide prefabricated drainage matting (such as Miradrain or J-Drain 400) be placed for the full height of the shoring wall between each column of soil nails. The drainage matting could be attached to the soil cut prior to placement of the temporary shotcrete facing. Near the bottom of the wall, centered in each drainage mat, a prefabricated connector (such as Drain Grate) should be connected to the drainage matting. The connector should be fitted with a 3-inch minimum diameter weep hole pipe that will extend through the face of the permanent foundation wall. The weep hole pipe should be connected to a tightline system leading to a suitable discharge. In addition to the above-reconn mended drainage measures, additional water proofing measures should be considered between the soil nail wall face and the back of permanent foundation walls such as Volclay panels. The project team should consult a waterproofing expert for additional waterproofing recommendations. CLOSURE The analysis and recommendations presented in this report are based, in part, on the explorations completed for this study. The number, location, and depth of the explorations were completed within the constraints of budget and site access so as to yield the information to formulate our recommendations. Project plans were in the preliminary stage at the time this report was prepared. We therefore recommend Zipper Geo Associates, LLC be provided an opportunity to review the final plans and specifications when they become available in order to assess that the recommendations and design Page 18 ZipperGeo Proposed Edmonds Apartments Project No. 1948.02 November 20, 2018 considerations presented in this report have been properly interpreted and implemented into the project design. The performance of earthwork, structural fill, foundations, and pavements depend greatly on proper site preparation and construction procedures. We recommend that Zipper Geo Associates, LLC be retained to provide geotechnical engineering services during the earthwork -related construction phases of the project. If variations in subsurface conditions are observed at that time, a qualified geotechnical engineer could provide additional geotechnical recommendations to the contractor and design team in a timely manner as the project construction progresses. This report has been prepared for the exclusive use of Goodman Real Estate and their agents, for specific application to the project discussed and has been prepared in accordance with generally accepted geotechnical engineering practices. No warranties, either express or implied, are intended or made. Site safety, excavation support, and clewatering requirements are the responsibility of others. In the event that changes in the nature, design, or location of the project as outlined in this report are planned, the conclusions and recommendations contained in this report shall not be considered valid unless Zipper Geo Associates, LLC reviews the changes and either verifies or modifies the conclusions of this report in writing. Page 19 END OF CHAIN ld, LINK FENCE BOA, 4P MN) OF LINE IRILL I OF o KER �1�405.21 0 RY -4-LL il 9.A @111 NI I N� 7//7 Q B-3 CB #4 4�2 405.�O RI .1 2.0%S ON 12" IE = 4 3.10 (S) 3'A S 427.2' 38 STORM WATeGETEN� TI ON VAULT BELOW PARKING SLAb B-5 C8 �M M 28'X3 M C A PR XP1,500 CF LIVE STORAGE 12� 1 �(I' OF LID 409.75 if 12' TO F RISER ±408.5 B 1 OF VAULT = ± 2. OTT LET IE.,= ±402.5 B I M OFTUMP, 98.5 OT "1/12" "X2 EE SH�T C5.'TWOR/ V DET�L 9� LF 121' D . 1.00%/ 01 12* SDM #1�01611A TYPE IW 42 . IT �Dlllw /406YI34 EW E 22.1"N) 2 417.57 (W) w 1 41;7�7 (i� OMH Rl— = 42 -Al 103' FROM 2'�CP t � -�114 �l )PERTY 2 4 4� NOTE 1 2" RCP p't 4;413' RIL 41�.51� 2 L if D I A SD SD 12" CP (S) A SS S S SS SM RIM - 421.6 406 ff ERTY ""PVC S,F,,& IN SSMH k1M 410 6 1' I 1 0 C Et�,= -4-Q.84' 8" P2S-1 VV- TYP TR INEL - 4X5,1' lb7 07. 9 0 5�5 0 2 JIT' AROA - SF B- B-4 4P8.42 8 IV"i ICB RIM 407.52 12- RCP (NW) 404�72' - RCP (E) 404 62' 12 18 4F 1�" �.I. LC9 RIM = 40759'__l PROP E 12� RCP (W) = 404,69' 0 YD — 118- DI (NS) = 403.69' BUILDINGA P 409".19 R(0 C� W 'JER SEMENT 0. "7yl2l 15 0984 /17 y YPE R �l 1 8 7 i�14 1 1T El 3 1 /417.44, PE 1 4 �F 1 D/. 0/2.02% 4.95 4.80 41 4 / 41 .8 581 ON AT'30' 13- 05,20 OP 2% 30 0 15 30 M1% @ LA ING MAX SLOPE N — — — — — — SCALE IN FEET RASH,ENCILOS — — — — — — AR A 4-L4-- —E)457.,3T SEE �ETAIL 1 TH i SHEET, FO�\ I DRIVEWAY,, SSMH RI�M = .54' SS 1'' 8- PVC N, S, & W C #1 CTR CHANNEL 40 1. 00' DI H T PE OP EB )p 41 251 IE lr DI(E)VI&92 1 415.16 IE �415.1 PROPOSED EDMONDS APARTMENTS LEGEND 23326 HWY. 99 EDMONDS, WASHINGTON B-1 BORRING NUMBER AND FIGURE 1 APPROXIMATE LOCATION SITE AND EXPLORATION PLAN DATE: NOV. 2018 Job No. 1948.02 Zipper Geo Associates, LLC FIGURE Z:\Projects\l 901 - 1950\1 948 Edmonds Apartments\l 948.01 - Geotech. Evaluation\Working File\Drafting\ACAD-1 7514 X-C3D.dwg 19019 36th Ave. W.,Suite E SHT. lof 1 Lynnwood, WA Pa = 10.41-11 (PLF) 20.8H (PSF) STATIC ACTIVE EARTH PRESSURE Pae = 19.41-1 (PSF) Pae = 12.2H2 (PLF) Pae = 4.91-1 (PSF) SEISMIC ACTIVE EARTH PRESSURE WEST BUILDING LINE FOUNDATION WALL - LATERAL EARTH PRESSURE DIAGRAMS ASSUMES PERMANENT WALL WILL BE CAST NEAT AGAINST SHORING NOTE: THE EARTH PRESSURES ABOVE ARE FOR PERMANENT FOUNDATION WALLS AND THE PROPOSED STORMWATER VAULT WALLS. THE EARTH PRESSURES DO NOT INCLUDE THE AFFECT OF SURCHARGES. FOR VEHICULAR LIVE LOAD TRAFFIC SURCHARGES, 2 FT OF ADDITIONAL SOIL ABOVE FINISHED GRADE MAY BE ASSUMED. FOR THE SEISMIC CONDITION, LIVE LOAD TRAFFIC SURCHARGES MAY BE IGNORED. THE EARTH PRESSURES ABOVE ASSUME ACTIVE CONDITIONS WILL PREVAIL AND THAT THE WEST BUILDING LINE FOUNDATION WALL WILL BE CAST NEAT AGAINST TEMPORARY SHORING. IF THE WEST WALL WILL BE BACKFILLED OR IF WALLS WILL BE BRACED PRIOR TO BACKFILLING, ZGA SHOULD BE CONSULTED FOR REVISED LATERAL EARTH PRESSURE RECOMMENDATIONS. NOTE: SUPERIMPOSE STATIC AND SEISMIC EARTH PRESSURES FOR THE SEISMIC LOAD CASE. i = 16.91-11 (PLF) 33.8H (PSF) STATIC ACTIVE EARTH PRESSURE Pae = 25.01-1 (PSF) Pae = 15.61-12 (PLF) Pae = 6.21-1 (PSF) SEISMIC ACTIVE EARTH PRESSURE ALL OTHER PERMANENT FOUNDATION RETAINING WALLS ASSUMES UNBRACED WALLS BACKFILLED WITH COMPACTED STRUCTURAL FILL APPENDIX A SUBSURFACE EXPLORATION PROCEDURES & LOGS F_A1:J:J a 0 111 SUBSURFACE EXPLORATION PROCEDURES AND LOGS Field Exploration Description Our field exploration for this project included 5 test borings completed on 1/16/18. The approximate exploration locations are shown on the Site and Exploration Plan, Figure 1. Exploration locations were determined by measuring off of existing site features shown on a site plan completed by the project civil engineer. The approximate ground surface elevation at the exploration locations was determined by interpolating from topographic information shown on the above -referenced site plan. As such, the exploration locations and elevations should be considered accurate only to the degree implied by the means and methods used to define them. Boring Procedures Our exploratory borings were advanced with a hollow stem auger, using a track -mounted drill rig operated by an independent drilling firm working under subcontract to our firm. An engineer from our firm continuously observed the borings, logged the subsurface conditions encountered, and obtained representative soil samples. All samples were stored in moisture -tight containers and transported to our laboratory for further visual classification and testing. After each boring was completed, the borehole was backfilled with bentonite clay. Throughout the drilling operation, soil samples were obtained at 2.5- to 5-foot depth intervals by means of the Standard Penetration Test (ASTIVI: D-1586). This testing and sampling procedure consists of driving a standard 2- inch outside diameter steel split spoon sampler 18 inches into the soil with a 140-pound hammer free falling 30 inches. The number of blows required to drive the sampler through each 6-inch interval is recorded, and the total number of blows struck during the final 12 inches is recorded as the Standard Penetration Resistance, or "blow count" (N value). If a total of 50 blows is struck within any 6-inch interval, the driving is stopped and the blow count is recorded as 50 blows for the actual penetration distance. The resulting Standard Penetration Resistance values indicate the relative density of granular soils and the relative consistency of cohesive soils. The enclosed boring logs describe the vertical sequence of soils and materials encountered in each boring, based primarily upon our field classifications and supported by our subsequent laboratory examination and testing. Where a soil contact was observed to be gradational, our logs indicate the average contact depth. Where a soil type changed between sample intervals, we inferred the contact depth. Our logs also graphically indicate the blow count, sample type, sample number, and approximate depth of each soil sample obtained from the boring, as well as any laboratory tests performed on these soil samples. If any groundwater was encountered in a borehole, the approximate groundwater depth, and date of observation, is depicted on the log. Groundwater depth estimates are typically based on the moisture content of soil samples, the wetted portion of the drilling rods, the water level measured in the borehole after the auger has been extracted, or through the use of an observation well. The boring logs presented in this appendix are based upon the drilling action, observation of the samples secured, laboratory test results, and field logs. The various types of soils are indicated as well as the depth where the soils or characteristics of the soils changed. It should be noted that these changes may have been gradual, and if the changes occurred between samples intervals, they were inferred. Boring Location: See Figure 1, Site and Exploration Plan Drilling Company: Holocene Drilling Bore Hole Dia.: 7" Top Elevation: 419' Drilling Method: Hollow Stem Auger Hammer Type: Auto B-1 Date Drilled: 1/16/2018 Drill Rig: D50 Lqgged by_ TLW :E a) SOIL DESCRIPTION 1]3 U) E W . -j Z 0 E < M U) C/) - a) -0 2 (D PENETRATION RESISTANCE (blows/foot) co 0 Q 0 - 0) S U) a) The stratification lines represent the approximate boundaries between soil types. The transition may be gradual. Refer to report text and appendices for additional information. Standard Penetration Test Hammer Weight and Drop: 0 20 40 60 7 inches of topsoil over loose, moist, brown, silty SAND, trace gravel 4 -1- � -I- -i- i-- I- --------------------------------------------- Dense, moist, gray, silty SAND, some gravel (Weathered Till) S-1 181, 11 14,11,11 1 37 — I I 1 1 1 14- 44444T'' 1 14 1 rL 11 1 111 1 -11 J��1-7-1 T-*--TTT--F-FT- -------------------------------------------- Medium dense, wet, light gray, silty SAND, some to trace gravel (Weathered Till) 11111111 111111111k S-2 18" 1 1 1 _%,I 41 4 44414,,1,1,1 1 1, 1 1, 13 --------------------------------------------- Very dense, moist, light gray, silty SAND, some to trace gravel 4 - 4 4 4 4 4 4 (Till) S-3 12" 7-177-1 -177- 77777 -1 TTT- -TTTT-T- T- 50/6 grades to with silt S-4 6" 50/1 -1 -1 -1 -1 1 77-17T-. T-. -T 77777- 0 4-+-1-44-4-4-44 -rT -t--r- -r-r r- t-- t- -177-1777- 77777TTTT- -TT77T77 F F -249- S-5 3" 50/3 at 21.0 feet possible cobbles -1 -f -1 -t t t-,-t I I I I ""t' 4T 44',l T T SAMPLELEGEND GROUNDWATER LEGEND % Fines (<0.075 mm) 2-inch O.D. split spoon sample Clean Sand 0 % Water (Moisture) Content 3-inch I.D. Shelby tube sample Bentonite Plastic Limit i 9 -] Liquid Limit Grout/Concrete Natural Water Content Screened Casing Edmonds Apartments TESTING KEY F-1 Blank Casing 23326 Hwy 99 GSA = Grain Size Analysis V Groundwater level at Edmonds, WA time of drilling (ATD) or 20OW = 200 Wash Analysis on date of Date: Jan. 2018 Project No.: 1948-01 Consol. = Consolidation Test measurement. Zipper Geo Associates BORING Att. = Atterberq Limits B-1 19019 36th Ave. W, Suite E LOG: Lynnwood, WA — Page 1 of Boring Location: See Figure 1, Site and Exploration Plan Drilling Company: Holocene Drilling Bore Hole Dia.: 7" Top Elevation: 419' Drilling Method: Hollow Stem Auger Hammer Type: Auto B-1 Date Drilled: 1/16/2018 Drill Rig: D50 Lqgged by_ TLW :E a) SOIL DESCRIPTION �3 U) E W . -j Z 0 E < M U) C/) - a) -0 2 (D 0 PENETRATION RESISTANCE (blows/foot) co 0 Q 0 - co 0) S U) a) The stratification lines represent the approximate boundaries between soil types. The transition may be gradual. Refer to report text and appendices for additional information. Standard Penetration Test Hammer Weight and Drop: 20 40 60 Very Dense, moist, light gray, SAND, with silt and gravel S-6 51, I- I- FR-1- 77777 7 -17 -1- 7 777777 7 -LLLLLLLLL MMM -JU-11-i'Lld-11 MHN !1111ll � HHM, 1- -1 -1 -1 A -4 -1 -1 - 44- 4 at 29.0 feet possible cobbles to boulders S-7 5" ,5015 -3Q- Boring completed at approximately 30 feet on 1/16/18. -t - -t -t -t -t -t -t t - No groundwater observed ATD. — I I I I I I -17-17-7-7-77- - I - I - I 7777777 I I I I IT T T777 -T- L L L 1- 1- U-1-1- -1 -1 �4- -I -t t ki�� -17-7-, TMW -777777 7777777-7- IIIIIII III -4 i 4 i i 4 i 444444�� i i i i i i - i 1!1111111 MHN NMI! 7-T-F-T-F-F-T SAMPLIELEGEND GROUNDWATER LEGEND %Fines (<0.075 mm) 2-inch O.D. split spoon sample Clean Sand 0 % Water (Moisture) Content 3-inch I.D. Shelby tube sample Bentonite Plastic Limit i e -] Liquid Limit Grout/Concrete Natural Water Content Screened Casing Edmonds Apartments TESTING KEY F-1 Blank Casing 23326 Hwy 99 GSA = Grain Size Analysis V Groundwater level at Edmonds, WA time of drilling (ATD) or 20OW = 200 Wash Analysis on date of Date: Jan. 2018 Project No.: 1948-01 Consol. = Consolidation Test measurement. Zipper Geo Associates BORING Att. = Atterberq Limits B-1 19019 36th Ave. W, Suite E LOG: Lynnwood, WA — Page 2 of Boring Location: See Figure 1, Site and Exploration Plan Drilling Company: Holocene Drilling Bore Hole Dia.: 7" Top Elevation: 430' Drilling Method: Hollow Stem Auger Hammer Type: Auto B-2 Date Drilled: 1/16/2018 Drill Rig: D50 Lqgged by_ TLW SOIL DESCRIPTION PENETRATION RESISTANCE (blows/foot) �3 U) E uj co 0) Standard Penetration Test :E The stratification lines represent the approximate boundaries . —1 Z 0 -0 Hammer Weight and Drop: 0 Q S -�5 a) between soil types. The transition may be gradual. Refer to E < 3: a) report text and appendices for additional information. M U) C/) 2 0 — (D 0 20 40 60 8 inches of topsoil over medium dense, moist, brown, silty SAND, trace gravel (Possible Fill) ------------------------------------------- Dense, moist, light brown, silty SAND, some gravel (Possible Fill) grades to loose and wet from 10.0 feet to 12.0 feet ------------------------------------------- Very dense, moist, light gray, gravelly SAND, with silt (Till) SAMPLELEGEND GROUNDWATER LEGEND 2-inch O.D. split spoon sample Clean Sand 3-inch I.D. Shelby tube sample Bentonite Grout/Concrete Screened Casing TESTING KEY F-1 Blank Casing GSA = Grain Size Analysis V Groundwater level at time of drilling (ATD) or 20OW = 200 Wash Analysis on date of Consol. = Consolidation Test measurement. Att. = Atterberq Limits S-1 7- S-2 18" S-5 1 12" 25 44 8 69 50/6 0 %Fines (<0.075 mm) 0 % Water (Moisture) Content Plastic Limit i e —] Liquid Limit Natural Water Content Edmonds Apartments 23326 Hwy 99 Edmonds, WA Date: Jan. 2018 Project No.: 1948.01 Zipper Geo Associates BORING B-2 19019 36th Ave. W, Suite E LOG: Lynnwood, WA — Page 1 of Boring Location: See Figure 1, Site and Exploration Plan Drilling Company: Holocene Drilling Bore Hole Dia.: 7" Top Elevation: 430' Drilling Method: Hollow Stem Auger Hammer Type: Auto B-2 Date Drilled: 1/16/2018 Drill Rig: D50 Lqgged by_ TLW :E a) SOIL DESCRIPTION �3 U) E W . -j Z 0 E < M U) C/) - a) -0 2 (D 0 PENETRATION RESISTANCE (blows/foot) co 0 Q 3: 0 - co 0) S U) a) The stratification lines represent the approximate boundaries between soil types. The transition may be gradual. Refer to report text and appendices for additional information. Standard Penetration Test Hammer Weight and Drop: 20 40 60 Very dense, moist, light gray, silty SAND, trace to some gravel S-6 2" 50/2 (Till) grades to with gravel F F F 1- 11111111 -LLLLLLLLL MMM -T -17 -1 111111111 7 -T-T-F-T-F-F llllll� -i-i-L-t-i-L-L S-7 12" 1+1-tititi- -1 -1 -1 �AL50/6 1 -t -t -t -t -t -t t t F-r-F-F-r-F- 111, -17-17-7-7-77 -1-17777 7777777 777-i-i-iT- S-8 4" k bU/4 A -t 7 T777 -T- f-F-F- 7-1-717-7-, L L L I- I- 1-1-1-1- 111111111 -1 -1 -1 --l-I'Ll 1 1 1 1 1 H -L' -'L 11 11 at 39.0 feet possible cobbles to boulders LILL S-9 4" 50/4 A Boring completed at approximately 40 feet on 1/16/18. No groundwater observed ATD. t 17-7-, --T7-T7-T-T -i-i-14-�-44 4 - 4 4 4 4 4 4 ir- Ir- -11 -11 -11 -11 -11 -11 - 41 -11- 41 7-T7-T77-T SAMPLELEGEND GROUNDWATER LEGEND %Fines (<0.075 mm) 2-inch O.D. split spoon sample Clean Sand 0 % Water (Moisture) Content 3-inch I.D. Shelby tube sample Bentonite Plastic Limit i e -] Liquid Limit Grout/Concrete Natural Water Content Screened Casing Edmonds Apartments TESTING KEY F-1 Blank Casing 23326 Hwy 99 GSA = Grain Size Analysis V Groundwater level at Edmonds, WA time of drilling (ATD) or 20OW = 200 Wash Analysis on date of Date: Jan. 2018 Project No.: 1948-01 Consol. = Consolidation Test measurement. Zipper Geo Associates BORING Att. = Atterberq Limits B-2 19019 36th Ave. W, Suite E LOG: Lynnwood, WA — Page 2 of Boring Location: See Figure 1, Site and Exploration Plan Drilling Company: Holocene Drilling Bore Hole Dia.: 7" Top Elevation: 427' Drilling Method: Hollow Stem Auger Hammer Type: Auto B-3 Date Drilled: 1/16/2018 Drill Rig: D50 Lqgged by_ TLW SOIL DESCRIPTION PENETRATION RESISTANCE (blows/foot) �3 U) E uj co 0) Standard Penetration Test :E The stratification lines represent the approximate boundaries . _1 Z 0 _0 Hammer Weight and Drop: 0 Q S _�5 a) between soil types. The transition may be gradual. Refer to E < a) report text and appendices for additional information. M U) C/) 2 0 — (D 0 20 40 60 7 inches of topsoil over loose, moist, gray -brown, silty SAND, trace gravel (Possible Fill) S-1 0.7 -1-1 _P7_77777TTTT TTT--F-FT- 5 i-L-L _LLLLLLL L -------------------------------------------- Dense, moist, gray, SAND, with gravel and silt (Weathered Till) s-, 1.5 . . . . . . 43 -------------------------------------------- -1 -f-t-t -t-t-. -t-t-t I -r t t-t t Very dense, moist, light gray, silty SAND, some gravel (Till) S-3 1.5 _4 50/6 S-4 1 0.1 grades to with silt S-5 :: 0 3 3 5014 at 21.0 feet possible cobbles to boulders "I'll" I I t 4411111 1 SAMPLELEGEND GROUNDWATER LEGEND 2-inch O.D. split spoon sample Clean Sand 3-inch I.D. Shelby tube sample Bentonite Grout/Concrete Screened Casing TESTING KEY F-1 Blank Casing GSA = Grain Size Analysis V Groundwater level at time of drilling (ATD) or 20OW = 200 Wash Analysis on date of Consol. = Consolidation Test measurement. Att. = Atterberq Limits 0 %Fines (<0.075 mm) 0 % Water (Moisture) Content Plastic Limit i e —] Liquid Limit Natural Water Content Edmonds Apartments 23326 Hwy 99 Edmonds, WA Date: Jan. 2018 Project No.: 1948.01 Zipper Geo Associates BORING B-3 19019 36th Ave. W, Suite E LOG: Lynnwood, WA — Page 1 of Boring Location: See Figure 1, Site and Exploration Plan Drilling Company: Holocene Drilling Bore Hole Dia.: 7" Top Elevation: 427' Drilling Method: Hollow Stem Auger Hammer Type: Auto B-3 Date Drilled: 1/16/2018 Drill Rig: D50 Lqgged by_ TLW SOIL DESCRIPTION PENETRATION RESISTANCE (blows/foot) �3 U) E uj co 0) Standard Penetration Test :E The stratification lines represent the approximate boundaries . —1 Z 0 -0 Hammer Weight and Drop: 0 Q S -�5 a) between soil types. The transition may be gradual. Refer to E < a) report text and appendices for additional information. M U) C/) 2 0 — co (D 0 20 40 60 Very Dense, moist, light gray, silty SAND, some gravel (Till) .6 S-7 = 0.1 Boring completed at approximately 31 feet on 1/16/18. No groundwater observed ATD. SAMPLELEGEND GROUNDWATER LEGEND 2-inch O.D. split spoon sample Clean Sand 3-inch I.D. Shelby tube sample Bentonite Grout/Concrete Screened Casing TESTING KEY F-1 Blank Casing GSA = Grain Size Analysis V Groundwater level at time of drilling (ATD) or 20OW = 200 Wash Analysis on date of Consol. = Consolidation Test measurement. Att. = Atterberq Limits 50/2 0 %Fines (<0.075 mm) 0 % Water (Moisture) Content Plastic Limit i e —] Liquid Limit Natural Water Content Edmonds Apartments 23326 Hwy 99 Edmonds, WA Date: Jan. 2018 Project No.: 1948.01 Zipper Geo Associates BORING B-3 19019 36th Ave. W, Suite E LOG: Lynnwood, WA — Page 2 of Boring Location: See Figure 1, Site and Exploration Plan Top Elevation: 413' Date Drilled: 1/16/2018 1 SOIL DESCRIPTION �R' :E The stratification lines represent the approximate boundaries 0- a) between soil types. The transition may be gradual. Refer to 0 report text and appendices for additional information. 7 inches of topsoil over medium dense, moist, light brown to brown, silty SAND, trace gravel (Weathered Till) ------------------------------------------- Medium dense, moist, light gray -brown, silty SAND (Weathered Till) ------------------------------------------- Very dense, moist, light gray, silty SAND, with gravel (Till) grades to with silt grades to silty Boring completed at approximately 21 feet on 1/16/18. No groundwater observed ATD. SAMPLELEGEND GROUNDWATER LEGEND 2-inch O.D. split spoon sample Clean Sand 3-inch I.D. Shelby tube sample Bentonite Grout/Concrete Screened Casing TESTING KEY F-1 Blank Casing GSA = Grain Size Analysis V Groundwater level at time of drilling (ATD) or 20OW = 200 Wash Analysis on date of Consol. = Consolidation Test measurement. Att. = Atterberq Limits Drilling Company: Holocene Drilling Bore Hole Dia.: 7" Drilling Method: Hollow Stem Auger Hammer Type: Auto Drill Rig: D50 Lqgged by_ TLW PENETRATION RESISTANCE (blows/foot) �3 U) E W a) Standard Penetration Test V . _j _0 Hammer Weight and Drop: C C E < M C/) co 2 (D 0 20 40 0 M_ S-1 7' 77777q,74- 77777TTTT TTT--F-F- 17 1 i 1 i 1 iLL L' L LL' S-2 18" :_�11111111_qli_ Al" ... .... 21 111111111 11111111141111- � S-3 181, �,Q�, 4, 44 :A 56 -4 ' 74 S-4 1 181, . . . L . LL F3013 S-5 _j.9" 1 -'-. ' _ _ 0 %Fines (<0.075 mm) 0 % Water (Moisture) Content Plastic Limit i e —] Liquid Limit Natural Water Content Edmonds Apartments 23326 Hwy 99 Edmonds, WA Date: Jan. 2018 Project No.: 1948.01 Zipper Geo Associates BORING B-4 19019 36th Ave. W, Suite E LOG: Lynnwood, WA — Page 1 of 1 Boring Location: See Figure 1, Site and Exploration Plan Drilling Company: Holocene Drilling Bore Hole Dia.: 7" Top Elevation: 412' Drilling Method: Hollow Stem Auger Hammer Type: Auto B-5 Date Drilled: 1/16/2018 Drill Rig: D50 Lqgged by_ TLW SOIL DESCRIPTION PENETRATION RESISTANCE (blows/foot) �3 U) E uj co 0) Standard Penetration Test :E The stratification lines represent the approximate boundaries . _1 Z 0 _0 Hammer Weight and Drop: 0 Q S _�5 a) between soil types. The transition may be gradual. Refer to E < a) report text and appendices for additional information. M U) C/) 2 0 — (D 0 20 40 60 9" of topsoil over dense, light gray -brown, silty SAND, trace gravel (Weathered Till) S-1 18" 45 77--177q177 [III [III 77777TTTT I I T*--F-F- 111i ___j ---1 -1 -1 -1 -L 1 11 1 , JLLL i-LILL'LL -------------------------------------------- Dense, wet, light gray, silty SAND, trace gravel (Till) S-2 10" 35 1 -4 44-4-4*4 44 at 6.0 feet possible cobbles -f-t-t -t-t- _t_t_t_t_---- - t- r f- grades to very dense and moist grades to with gravel S-3 181, 'Q 4 50/4 _f _H -f-f _f -f-f _+ _t _t _t t t t t t F- t__ - S-4 T i � � i � i i I i � � i � � i � i i � I I li 1, A k 50/6 S-5 :: 8" U 50/4 S-6 :: 7' 50/4 grades to some gravel S-7 8- . .. .. . A 50/6 at 21.0 feet possible cobbles to boulders -��--4-4-4-44 44444++++- -+4-4-4-4- S-8 7' 50/4 SAMPLELEGEND GROUNDWATER LEGEND 2-inch O.D. split spoon sample Clean Sand 3-inch I.D. Shelby tube sample Bentonite Grout/Concrete Screened Casing TESTING KEY F-1 Blank Casing GSA = Grain Size Analysis V Groundwater level at time of drilling (ATD) or 20OW = 200 Wash Analysis on date of Consol. = Consolidation Test measurement. Att. = Atterberq Limits 0 %Fines (<0.075 mm) 0 % Water (Moisture) Content Plastic Limit i 9 —] Liquid Limit Natural Water Content Edmonds Apartments 23326 Hwy 99 Edmonds, WA Date: Jan. 2018 Project No.: 1948.01 Zipper Geo Associates BORING B-5 19019 36th Ave. W, Suite E LOG: Lynnwood, WA — Page 1 of Boring Location: See Figure 1, Site and Exploration Plan Drilling Company: Holocene Drilling Bore Hole Dia.: 7" Top Elevation: 412' Drilling Method: Hollow Stem Auger Hammer Type: Auto B-5 Date Drilled: 1/16/2018 Drill Rig: D50 Lqgged by_ TLW SOIL DESCRIPTION PENETRATION RESISTANCE (blows/foot) �3 U) E uj co 0) Standard Penetration Test :E The stratification lines represent the approximate boundaries . —1 Z 0 -0 Hammer Weight and Drop: 0 Q S -�5 a) between soil types. The transition may be gradual. Refer to E < a) report text and appendices for additional information. M U) C/) 2 0 — co (D 0 20 40 60 Very dense, moist, light gray, silty SAND, some gravel .6 grades to with silt Boring completed at approximately 30 feet on 1/16/18. SAMPLELEGEND GROUNDWATER LEGEND 2-inch O.D. split spoon sample Clean Sand 3-inch I.D. Shelby tube sample Bentonite Grout/Concrete Screened Casing TESTING KEY F-1 Blank Casing GSA = Grain Size Analysis V Groundwater level at time of drilling (ATD) or 20OW = 200 Wash Analysis on date of Consol. = Consolidation Test measurement. Att. = Atterberq Limits 0 1 4" 50/3 %Fines (<0.075 mm) 0 % Water (Moisture) Content Plastic Limit i e —] Liquid Limit Natural Water Content Edmonds Apartments 23326 Hwy 99 Edmonds, WA Date: Jan. 2018 Project No.: 1948.01 Zipper Geo Associates BORING B-5 19019 36th Ave. W, Suite E LOG: Lynnwood, WA — Page 2 of APPENDIX B LABORATORY TESTING PROCEDURES & RESULTS APPENDIX B LABORATORY TESTING PROCEDURES AND RESULTS A series of laboratory tests were performed by ZGA and a subcontract testing laboratory during the course of this study to evaluate the index and geotechnical engineering properties of the subsurface soils. Descriptions of the types of tests performed are given below. Visual Classification Samples recovered from the exploration locations were visually classified in the field during the exploration program. Representative portions of the samples were carefully packaged in moisture tight containers and transported to our laboratory where the field classifications were verified or modified as required. Visual classification was generally done in accordance with ASTM D2488. Visual soil classification includes evaluation of color, relative moisture content, soil type based upon grain size, and accessory soil types included in the sample. Soil classifications are presented on the exploration logs in Appendix A. Moisture Content Determinations Moisture content determinations were performed on representative samples obtained from the explorations in order to aid in identification and correlation of soil types. The determinations were made in general accordance with the test procedures described in ASTM D 2216. Moisture contents are presented on the exploration logs in Appendix A. Grain Size Analysis A grain size analysis indicates the range in diameter of soil particles included in a particular sample. Grain size analyses were performed on representative samples in general accordance with ASTM: D-2487. The results of the grain size determinations for the samples were used in classification of the soils, and are presented in this appendix. GRAIN SIZE ANALYSIS Test Results Summary ASTM D 422 100 90 80 70 Cal W 60 LU z 50 z LU L) W 40 LU (L 30 20 10 0 1000.000 100.000 10.000 1.000 0.100 0.010 0.001 PARTICLE SIZE IN MILLIMETERS ame Fi,. --Ns- I -dium Fine it Clay BOULDERS COBBLES [, G RAVEL SA D FINE GRAINED Comments: Exploratio Sample Depth (feet) Moisture Fines (%) Description B-2 t S2 5 ft. 7.7 41.2 Silty SAND, some gravel Project No.: 1948.01 PROJECT NAME: Zipper Geo Associates, LLC Geotechnical and Environmental Consultants DATEOFTESTING: 1/19/2018 Edmonds Apartments GRAIN SIZE ANALYSIS Test Results Summary ASTM D 422 100 90 80 70 Cal W 60 LU z 50 z LU L) W 40 LU (L 30 20 10 0 1000.000 100.000 10.000 1.000 0.100 0.010 0.001 PARTICLE SIZE IN MILLIMETERS ame Fi,. --Ns- I -dium Fine it Clay BOULDERS COBBLES [, G RAVEL SA D FINE GRAINED Comments: Exploratio Sample Depth (feet) Moisture Fines (%) Description B-2 t S4 15 ft. 5.2 14.5 Gravelly SAND, with silt Project No.: 1948.01 PROJECT NAME: Zipper Geo Associates, LLC Geotechnical and Environmental Consultants DATEOFTESTING: 1/19/2018 Edmonds Apartments GRAIN SIZE ANALYSIS Test Results Summary ASTM D 422 100 90 80 70 Cal W 60 LU z 50 z LU L) W 40 LU (L 30 20 10 0 1000.000 100.000 10.000 1.000 0.100 0.010 0.001 PARTICLE SIZE IN MILLIMETERS ame Fi,. --Ns- I -dium Fine it Clay BOULDERS COBBLES [, G RAVEL SA D FINE GRAINED Comments: Exploratio Sample Depth (feet) Moisture Fines (%) Description B-3 t S2 5 ft. 7.7 24.0 Silty SAND, with gravel Project No.: 1948.01 PROJECT NAME: Zipper Geo Associates, LLC Geotechnical and Environmental Consultants DATEOFTESTING: 1/19/2018 Edmonds Apartments GRAIN SIZE ANALYSIS Test Results Summary ASTM D 422 100 90 80 70 Cal W 60 LU z 50 z LU L) W 40 LU (L 30 20 10 0 1000.000 100.000 10.000 1.000 0.100 0.010 0.001 PARTICLE SIZE IN MILLIMETERS ame Fi,. --Ns- I -dium Fine it Clay BOULDERS COBBLES [, G RAVEL SA D FINE GRAINED Comments: Exploratio Sample Depth (feet) Moisture Fines (%) Description B-4 t S3 10 ft. 7.9 31.7 Silty SAND, with gravel Project No.: 1948.01 PROJECT NAME: Zipper Geo Associates, LLC Geotechnical and Environmental Consultants DATEOFTESTING: 1/19/2018 Edmonds Apartments GRAIN SIZE ANALYSIS Test Results Summary ASTM D 422 100 90 80 70 Cal W 60 LU z 50 z LU L) W 40 LU (L 30 20 10 0 1000.000 100.000 10.000 1.000 0.100 0.010 0.001 PARTICLE SIZE IN MILLIMETERS ame Fi,. --Ns- I -dium Fine it Clay BOULDERS COBBLES [, G RAVEL SA D FINE GRAINED Comments: Exploratio Sample Depth (feet) Moisture Fines (%) Description B-5 t S4-S6 12.5 to 17.5 ft. 6.6 33.4 Silty SAND, with gravel Project No.: 1948.01 PROJECT NAME: Zipper Geo Associates, LLC Geotechnical and Environmental Consultants DATEOFTESTING: 1/19/2018 Edmonds Apartments