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HomeMy WebLinkAboutEx19_Geotechnical_Engineering_Report_KR GEOTECHNICAL REPORT Elliott Bridge No. 3166 Replacement HWA Job No. 1996-143-21 Prepared for ABKJ, INC. April 4, 2003 GEOTECHNICAL REPORT Kennydale 320 Pressure Zone Reservoir Renton, Washington HWA Project No. 2016-078-21 Prepared for Murraysmith May 21, 2018 EXHIBIT 19 RECEIVED Clark Close 06/25/2020 PLANNING DIVISION DocuSign Envelope ID: EBD590F4-4493-4D53-B777-F51C36D33E6E DocuSign Envelope ID: EBD590F4-4493-4D53-B777-F51C36D33E6E TABLE OF CONTENTS Page 1.0 INTRODUCTION ....................................................................................................1 1.1 GENERAL .......................................................................................................1 1.2 PROJECT DESCRIPTION ..................................................................................1 2.0 FIELD AND LABORATORY INVESTIGATIONS ...............................................2 2.1 GEOTECHNICAL SUBSURFACE EXPLORATION ................................................2 2.2 INFILTRATION TESTING PROGRAM ................................................................3 2.3 LABORATORY TESTING .................................................................................3 2.4 ADDITIONAL EXPLORATIONS ........................................................................3 3.0 SITE CONDITIONS ................................................................................................4 3.1 SURFACE CONDITIONS ...................................................................................4 3.2 GENERAL GEOLOGIC CONDITIONS ................................................................4 3.3 SITE SOIL CONDITIONS ..................................................................................4 3.4 GROUNDWATER .............................................................................................5 4.0 CONCLUSIONS AND RECOMMENDATIONS ...................................................6 4.1 GENERAL .......................................................................................................6 4.2 SEISMIC DESIGN CONSIDERATIONS ...............................................................6 4.2.1 Seismic Design Parameters ...........................................................6 4.2.2 Liquefaction ...................................................................................7 4.2.3 Ground Rupture .............................................................................8 4.3 ANTICIPATED RESERVOIR SETTLEMENTS ......................................................8 4.3.1 Elastic Settlements of Shallow Footings .......................................8 4.3.2 Seismic Settlement ........................................................................8 4.4 FOUNDATIONS RECOMMENDATIONS ..............................................................9 4.4.1 Auger-Cast Concrete Piles ............................................................9 4.4.2 Construction Considerations .........................................................10 4.4.3 Lateral Design Parameters .............................................................11 4.5 RETAINING WALLS ........................................................................................12 4.5.1 Earth Pressures and Drainage Requirements .................................12 4.5.2 Structural Earth Wall Global Stability ..........................................13 4.5.3 Wall Drainage ................................................................................13 4.5.4 General Wall Subgrade Preparation ..............................................14 4.6 UTILITIES ......................................................................................................14 4.6.1 Flexible Utility Connections .........................................................15 4.6.2 Bedding and Pipe Support .............................................................15 4.6.3 Trench Backfill ..............................................................................16 4.7 STORMWATER MANAGEMENT .......................................................................16 4.8 BELOW-GRADE STRUCTURES ........................................................................17 4.9 HMA PAVEMENT ..........................................................................................17 DocuSign Envelope ID: EBD590F4-4493-4D53-B777-F51C36D33E6E Table of Contents (Continued) 2016-078 Revised Final Geotechnical Report ii HWA GEOSCIENCES INC. 4.9.1 Placement of HMA ........................................................................18 4.9.2 HMA Drainage ..............................................................................19 4.10 PERVIOUS CONCRETE PAVEMENT DESIGN ....................................................19 4.10.1 Pervious Portland Cement Concrete ..............................................20 4.10.2 Recharge Bed Design and Subgrade Preparation ..........................20 4.11 SITE EARTHWORK RECOMMENDATIONS ........................................................21 4.11.1 Structural Fill and Compaction .....................................................21 4.11.2 Temporary Excavations .................................................................22 4.11.3 Wet Weather Earthwork ................................................................22 5.0 CONDITIONS AND LIMITATIONS......................................................................23 6.0 REFERENCES .........................................................................................................25 List of Figures (Following Text) Figure 1 Vicinity Map Figure 2 Site and Exploration Plan Figure 3 Geologic Map Figure 4 BH-1 Groundwater Elevation Data Figure 5 Preliminary Pile Layout Figure 6 Lateral Erath Pressures for Air Gap/Dechlor MH APPENDICES Appendix A: Field Exploration Figure A-1 Legend of Terms and Symbols Used on Exploration Log Figures A-2 – A-4 Logs of Borings BH-1 through BH-3 Figure A-5 Log of Test Pit TP-1 Appendix B: Laboratory Testing Figures B-1 – B-6 Particle-Size Analysis of Soils Appendix C: Additional Explorations DocuSign Envelope ID: EBD590F4-4493-4D53-B777-F51C36D33E6E GEOTECHNICAL REPORT KENNYDALE 320 PRESSURE ZONE RESERVOIR RENTON, WASHINGTON 1.0 INTRODUCTION 1.1 GENERAL This report summarizes the results of the geotechnical studies performed by HWA GeoSciences Inc. (HWA) for the proposed Kennydale 320 Pressure Zone Reservoir project in Renton, Washington. The approximate location of the project site is shown on the Vicinity Map, Figure 1, and on the Site and Exploration Plan, Figure 2. Our field work included drilling three (3) machine-drilled borings and conducting one (1) Pilot Infiltration Test (PIT) in the vicinity of the proposed reservoir to evaluate soil and groundwater conditions. Laboratory tests were conducted on selected soil samples to determine relevant engineering properties of the subsurface soils. 1.2 PROJECT DESCRIPTION We understand that the City of Renton proposes to construct a new water reservoir for the City of Renton Water Utility. This reservoir is to provide storage for emergency conditions and operations related to the Houser Way Booster Pump Station. Additionally, the reservoir will help prevent potential water main issues by reducing potential pressure gradients in the 320 Zone. The reservoir is proposed to be constructed in the Kennydale neighborhood on a city- owned parcel #334210-3245 located at 1404 North 30th Street, just west of I-405. The subject parcel is currently undeveloped and slopes gently upwards from the southwest to northeast, varying in elevation from approximately 208 feet to 226 feet. The reservoir will consist of a welded steel standpipe-style tank 50 feet in diameter and about 100 feet high. It will have a storage capacity of approximately 1.29 million gallons. Additional improvements associated with the proposed reservoir will include an access roadway, retaining walls, below grade storm detention system, control valve, flow meter and quality vaults, as well as inlet and outlet piping for the reservoir. Onsite infiltration is the preferred method of storm water management for this site. On-site stormwater management will be implemented via open bottom below grade storm detention facility and permeable pavement. DocuSign Envelope ID: EBD590F4-4493-4D53-B777-F51C36D33E6E May 21, 2018 HWA Project No. 2016-078-21 2016-078 Revised Final Geotechnical Report 2 HWA GEOSCIENCES INC. 2.0 FIELD AND LABORATORY INVESTIGATIONS 2.1 GEOTECHNICAL SUBSURFACE EXPLORATION In support of design of the proposed Kennydale 320 Pressure Zone Reservoir project, HWA drilled three (3) exploratory borings, designated BH-1 through BH-3, to determine the subsoil and groundwater conditions. The locations of these borings are shown on Figure 2. These borings were drilled by Environmental Drilling Inc. (EDI) of Snohomish, Washington, under subcontract to HWA. The drilling was performed using a B-61 mobile truck rig equipped with 4.25-inch inside-diameter hollow-stem auger and an automatic hydraulic hammer. In each boring, Standard Penetration Test (SPT) sampling was performed at selected depth intervals and the SPT resistance (“N-value”) of the soil was logged. This resistance, or N-value, provides an indication of relative density of granular soils and the relative consistency of cohesive soils. Boring BH-1 was positioned in the center of the proposed tank location and drilled to a depth of 51.3 feet below ground surface. Upon completion of boring BH-1, a 2-inch diameter stand pipe piezometer was installed to monitor the ground water levels. The piezometer installed in BH-1 was screened from depths of 40 to 50 feet. Boring BH-2 was drilled to a depth of 73 feet. It was located near the western perimeter of the proposed tank location. Boring BH-3 was drilled to a depth of 21.5 feet below ground surface near the center of the proposed below grade storm water facility. In each boring, Standard Penetration Test (SPT) sampling was performed at selected intervals and the SPT resistance (“N-value”) of the soil was logged. This resistance, or N-value, provides an indication of relative density of granular soils and the relative consistency of cohesive soils. A geologist from HWA logged the explorations and recorded pertinent information, including sample depths, stratigraphy, soil descriptions, and ground water occurrence. Soil samples obtained from the exploration were classified in the field and representative portions were placed in plastic bags. These soil samples were then taken to our Bothell, Washington, laboratory for further examination and testing. Logs for borings BH-1 through BH-3 are presented in Appendix A of this report. The stratigraphic contacts shown on the exploration logs represent the approximate boundaries between soil types; actual transitions may be more gradual. The soil and ground water conditions depicted are only for the specific date and location reported and, therefore, are not necessarily representative of other locations and times. DocuSign Envelope ID: EBD590F4-4493-4D53-B777-F51C36D33E6E May 21, 2018 HWA Project No. 2016-078-21 2016-078 Revised Final Geotechnical Report 3 HWA GEOSCIENCES INC. 2.2 INFILTRATION TESTING PROGRAM Phase 2 of our exploration program consisted of conducting one (1) Pilot Infiltration Test (PIT), designated PT-1, at the location of the proposed stormwater faciality. The excavation for the PIT was made on July 24 and 25, 2017 by Kelly’s Excavating Inc. of Pacific, Washington, under subcontract to HWA. PT-1 was excavated to a depth of 16 feet bgs to assess infiltration rates at the proposed depth of the infiltration facility. The sidewalls of the excavation were shored with a steel trench box. The dimensions of the inside of the shoring were approximately 4 feet by 10 feet; however, the dimensions of the test pit inside of the trench box were 3 feet by 6 feet. The test consisted of introducing water at a known flow rate into the excavation. Water was obtained from a nearby water service in cooperation with the City of Renton Utility Division and pumped into the excavation using a water trailer provided by Kelly’s Excavating, Inc. Slotted pipe terminating in a 5-gallon bucket was used to dissipate the water into the excavation. Water levels were measured with a staff gauge installed in the excavation along with a Levelogger Edge water level datalogger. At selected intervals, HWA recorded total flow through a meter and calculated the flow rate. The flow rate was adjusted to establish and maintain a water level of approximately 1 foot above the base of the PIT. After approximately 7 hours of flow, the water was turned off. Water levels in the excavation were monitored until all the water had drained out of the test pit. A geologist from HWA logged the exploration and recorded all the pertinent information including sample depths, stratigraphy, soil engineering characteristics, and ground water occurrence at the time of excavation. More information regarding the PIT procedure and results are presented in Section 4.7 of this report. 2.3 LABORATORY TESTING Laboratory tests including determination of natural moisture content and grain size distribution, were conducted on selected soil samples to characterize certain engineering and index properties of the site soils. All testing was conducted in general accordance with appropriate American Society for Testing and Materials (ASTM) standards, as discussed in Appendix B. The test results and a discussion of laboratory test methodology are presented in Appendix B, or displayed on the boring logs in Appendix A, as appropriate. 2.4 ADDITIONAL EXPLORATIONS Geotechnical explorations, performed for the Renton Fire Station 15 project by HWA in 2017, were reviewed and utilized in this study. Three borings and one PIT test were performed as part of this project. The location of these borings are shown on Figure 2. Copies of these boring logs are provided in Appendix C. DocuSign Envelope ID: EBD590F4-4493-4D53-B777-F51C36D33E6E May 21, 2018 HWA Project No. 2016-078-21 2016-078 Revised Final Geotechnical Report 4 HWA GEOSCIENCES INC. 3.0 SITE CONDITIONS 3.1 SURFACE CONDITIONS The reservoir site is located in the Kennydale neighborhood on a city-owned parcel at 1404 North 30th Street, just west of I-405. The parcel slopes slightly upwards from the southwest to northeast, varying in elevation from approximately 208 feet to 226 feet. The parcel is predominately vegetated with grass, apple trees and various underbrush. 3.2 GENERAL GEOLOGIC CONDITIONS General geologic information specific to the project area was obtained from the Geologic Map of King County (Booth et. al., 2006). A portion of this geologic map is shown in Figure 3 of this report. The map indicates the project vicinity is underlain by deposits of the Fraser glaciation during Pleistocene era described as Vashon recessional outwash. Recessional outwash deposits are characterized by stratified sand and gravel, moderately to well sorted, with less common silty sand and rare silty clay. These materials have not been glacially overridden and are typically loose to medium dense. 3.3 SITE SOIL CONDITIONS Our interpretations of subsurface conditions are based on the results of our field explorations, review of available geologic and geotechnical data, and our experience in similar geologic settings. In general, the soils underlying the site consist of loose to medium dense, recessional outwash sands over dense to very dense glacial till and advance outwash deposits to depth. Each major soil unit is described below, with materials interpreted as being youngest in origin and nearest to the surface described first. • Recessional Outwash: Recessional outwash consisting of loose to medium dense, olive brown, clean to silty sand was encountered in all explorations. These soils were observed to range from 40 to 44 feet thick in BH-1 and BH-2, respectively. BH-3 and PT-1 were terminated within the recessional outwash soils. Recessional outwash was deposited by meltwater emanating from the retreating glacial ice sheet. Consequently, it has not been overridden by glacial and is typically loose to medium dense. The upper 5 feet of recessional outwash in borings BH-1 and BH-2 consisted of loose to medium dense silt. • Glacial Till: Glacial till soils were encountered in borings BH-1 and BH-2, beneath the recessional outwash deposits. The glacial till soils consisted of dense to very dense, gray, silty sand with gravel. The upper portions of the till were generally weathered, somewhat less dense and finer grained. Glacial till is the material which was deposited along the sole of the glacial ice as lodgment till. It consists of an DocuSign Envelope ID: EBD590F4-4493-4D53-B777-F51C36D33E6E May 21, 2018 HWA Project No. 2016-078-21 2016-078 Revised Final Geotechnical Report 5 HWA GEOSCIENCES INC. unsorted mixture of clay, silt, sand and gravel, which is very dense, having been consolidated by the weight of greater than 2,000 feet of ice. It is also known to contain scattered cobbles and boulders. This unit is locally referred to as "hardpan", because of its appearance similar to concrete. Till is relatively impermeable, except where sandy zones are encountered. Generally, the till forms an impervious layer below which surface water cannot penetrate. Where sand overlies the till, water is often perched on top of the till. Glacial till encountered in BH-2 was observed to be 20 feet in thickness. BH-1 was terminated within the glacial till unit. Although not encountered in our borings, large cobbles and boulders are known to exist in glacial deposits. • Advance Outwash: Advance outwash soils were encountered below the glacial till deposit at the location of boring BH-2. Advance outwash soils generally consist of olive brown to gray, silty, fine to medium sand with varying amounts of gravel. These deposits were laid down by streams issuing from the glacial front as the ice sheet advanced. They have been overlain and densified by the weight of the ice, and range in density from dense to very dense. In general, the sediments are coarser at higher levels in the unit, because the streams deposited larger materials closer to the ice. 3.4 GROUNDWATER At the time of our field investigation, perched groundwater seepage was observed only in boring BH-2 at a depth 43.5 feet below ground surface. Groundwater appears to be near the contact of recessional outwash and glacial till deposits in BH-2. A 2-inch diameter piezometer stand pipe with 10 feet of slotted screen was installed at BH-1 to a depth of 50 feet below grade. A ground water transducer was installed in the well on November 11, 2016. The transducer continually recorded the water level within the well casing, beginning with the date of installation. HWA periodically downloaded transducer data from the date of installation through January 2, 2018. Ground water level data collected using the transducer installed inside boring BH-1 is presented in Figure 4. Figure 4 shows the groundwater at about 40 feet below ground surface. The groundwater seepage observed may not necessarily be indicative of other times and/or locations and it is anticipated that groundwater conditions will vary depending on the weather, local subsurface conditions, and other factors. Prospective contractors should be prepared to encounter perched groundwater if excavating near the contact of the weather till. DocuSign Envelope ID: EBD590F4-4493-4D53-B777-F51C36D33E6E May 21, 2018 HWA Project No. 2016-078-21 2016-078 Revised Final Geotechnical Report 6 HWA GEOSCIENCES INC. 4.0 CONCLUSIONS AND RECOMMENDATIONS 4.1 GENERAL The proposed reservoir site is underlain by recessional outwash soils over glacial till with advance outwash sands at depth. The medium dense, recessional outwash sands will experience elastic settlement due to the increases in load associated with the proposed structure. It is our understanding that this magnitude of anticipated differential settlement may exceed the tolerances of a conventional membrane slab foundation system. Additionally, the expected overturning loads due to the tank height are larger than can be resisted with a reasonable shallow foundation system. Therefore, the reservoir will require a deep foundation system to avoid settlement-induced damage to the proposed structure and to resist the expected overturning loads. We recommend that this foundation system consist of auger-cast concrete piles bearing in the underlying glacially consolidated soils. Differential displacement is also likely to occur during and after a seismic event. Horizontal and vertical differential displacements are expected between the auger-cast pile supported structures and their associated piping during ground shaking. Some permanent vertical settlement is also expected after ground shaking stops. To allow for these types of differential displacements without significant damage to the structures and their piping, we recommend flexible joints be incorporated into the design between the pipes and the structures. On-site stormwater management will be implemented via an open bottom, below grade, storm detention facility and by permeable pavement around the water tank. It should be noted that sandy silt soils having a high percentage of fines were encountered within 5 to 7 feet of the ground surface. These soils are not conducive to infiltration. Therefore, below the permeable pavement we recommend over-excavation to remove the 5 to 7 feet of fine-grained soils. The over-excavated area should be backfill with permeable ballast, per WSDOT Standard Specification 9-03.9(2). Recommendations related to site seismicity, foundations, retaining walls, utilities, below-grade structures, stormwater management, earthwork, and pavement are presented in the following sections. 4.2 SEISMIC DESIGN CONSIDERATIONS 4.2.1 Seismic Design Parameters Earthquake loading for the structures at the project site was developed in accordance with the 2012 International Building Code (IBC), (ICC, 2012). The IBC requires above-grade structures be designed for the inertial forces induced by a “Maximum Considered Earthquake” (MCE), which corresponds to an earthquake with a 2% probability of exceedance (PE) in 50 years DocuSign Envelope ID: EBD590F4-4493-4D53-B777-F51C36D33E6E May 21, 2018 HWA Project No. 2016-078-21 2016-078 Revised Final Geotechnical Report 7 HWA GEOSCIENCES INC. (approximately 2,475-year return period). Accordingly, the relevant probabilistic spectral response parameters were developed using the United States Geological Survey’s website. The IBC accounts for the effects of site-specific subsurface ground conditions on the response of structures in terms of site classes. Site classes are defined by the average density and stiffness of the soil profile underlying the site. The Site Class can be correlated to the average standard penetration resistance (NSPT) in the upper 100 feet of the soil profile. Based on our characterization of the subsurface conditions, the subject site classifies as IBC Site Class D. Table 1 presents the design spectral seismic coefficients obtained for this site based on risk category I/II/III. The design peak ground acceleration for use in computing lateral earth pressures was computed to be 0.385 g. Based on the SDS and SD1 values, the site is considered as Seismic Design Category D. Table 1. Design Seismic Coefficients for IBC 2012 Code Based Evaluation Site Class Spectral Acceleration at 0.2 sec. SS(1), g Spectral Acceleration at 1.0 sec S1(2), g Design Spectral Acceleration at 0.2 sec. SDS(3), g Design Spectral Acceleration at 1.0 sec. SD1(4), g Site Coefficients Peak Horizontal Acceleration PGA, (g) Fa(5) Fv(6) D 1.444 0.546 0.963 0.546 1.0 1.500 0.385 (1) SS = Mapped spectral response acceleration parameter at short periods (at a period of 0.2 sec) (2) S1 = Mapped spectral response acceleration parameter at a period of one second (3) SDS = Design spectral response acceleration parameter at short periods (at a period of 0.2 sec) (4) SD1 = Design spectral response acceleration parameter at a period of one second (5) Fa = short period site coefficient (at a period of 0.2 sec) (6) Fv = long period site coefficient (at a period of one second) The project site is located within about 2 miles of the Seattle Fault Zone. The main seismic consideration for the site is the large amplitude of the ground motions associated with its proximity to the fault, which is accounted for in the design seismic coefficients. With respect to the design parameters for the vertical accelerations, the recommendations provided in the ASCE 7-10 Section 12.4.2.2 (ASCE, 2010) should be applied. 4.2.2 Liquefaction Primary factors controlling the development of liquefaction include the intensity and duration of strong ground motions, the characteristics of subsurface soils, in-situ stress conditions and the depth to ground water. Based on the ground water elevations observed in our explorations, the materials that are saturated are dense to very dense and will not be subject to liquefaction during shaking. Therefore, liquefaction will not be a design consideration for this project. DocuSign Envelope ID: EBD590F4-4493-4D53-B777-F51C36D33E6E May 21, 2018 HWA Project No. 2016-078-21 2016-078 Revised Final Geotechnical Report 8 HWA GEOSCIENCES INC. 4.2.3 Ground Rupture Based on a review of the existing geologic data, there are no known active faults at this site; therefore, ground rupture is not a design consideration for this site. 4.3 ANTICIPATED RESERVOIR SETTLEMENTS The soils underlying the reservoir site consist of recessional outwash over glacial till with advance outwash at depth. The density and material properties of the recessional outwash sands are such that we anticipate significant settlements of shallow foundations under static and seismic loading conditions. We expect that these settlements will be differential in nature. A further discussion of the anticipated settlement magnitudes is provided below. 4.3.1 Elastic Settlements of Shallow Footings Elastic settlement is the vertical component of soil compression under static loading. These settlements occur relatively rapidly upon the application of load and are dependent on the elastic properties of the soils underlying the proposed foundation. Loose to medium dense soils generally undergo larger elastic settlements than denser materials such as glacial till. The recessional outwash soils within the upper 44 feet consist of loose to medium dense sands that will undergo significant elastic settlements under the static loading of the reservoir. Using the computer program Settle 3D (Rocscience, 2013), HWA modeled the anticipated elastic settlement under the load of the proposed reservoir foundations. Based on a typical mat foundation layout, we estimate that the proposed tank could experience elastic settlement of about 3 inches at the center of the tank and 1 inch around the edge. Therefore, the structure will undergo a differential settlement of about 2 inches over 50 feet if a conventional mat foundation is used. Therefore, the design team has indicated that a mat or conventional spread footing system is not appropriate to support the anticipated loads of the reservoir. Auger-cast piles is the desire foundation system. Considering that the reservoir will be supported on auger-cast concrete piles, we expect settlement of the reservoir to be less than ½ inch. 4.3.2 Seismic Settlement Settlement of the ground surface can occur in dry materials due to reorganization of the individual soil particles during earthquake shaking. We expect that the loose to medium dense recessional outwash soils, underlying the tank location, will experience densification during the design earthquake. Therefore, non-pile supported structures at the site could experience some settlement during the design event. We have estimated the magnitude of the settlements using procedures developed by Tokimatsu and Seed (1987). The results of these analyses are presented in Table 2 below. These differential settlements are expected to occur near the end of seismic shaking. DocuSign Envelope ID: EBD590F4-4493-4D53-B777-F51C36D33E6E May 21, 2018 HWA Project No. 2016-078-21 2016-078 Revised Final Geotechnical Report 9 HWA GEOSCIENCES INC. Table 2. Estimated Differential Settlement due to Earthquake Induced Ground Motions Estimated Differential Settlement for the Design Based Event (PGA = 0.385 g) Estimated Differential Settlement for Risk-Targeted Level Event (PGA = 0.47g) 0.66-inch over 50 feet 0.86-inch over 50 feet Differential displacement is also likely to occur during and after a seismic event. Horizontal and vertical differential displacements are expected between the auger-cast pile supported structures and their associated piping during ground shaking. Some permanent vertical settlement is also expected after ground shaking stops, as shown in Table 2. To allow for these types of differential displacements without significant damage to the structures and their piping, we recommend flexible joints be incorporated into the design between the pipes and the structures. 4.4 FOUNDATIONS RECOMMENDATIONS Based on the above described anticipated differential settlements we expect that the proposed reservoir if founded on spread footings or a mat foundation could experience elastic plus seismic differential settlements of the order of 3 inches over 50 feet. It is our understanding that this magnitude of differential settlement would exceed the tolerances of a conventional membrane slab foundation system. Additionally, the height of the tank is such that overturning loads are high and are a significant part of the foundation design. Based on this information Peterson Structural Engineers (PSE) has indicated that a mat or a spread footing system for the reservoir are not adequate to support the loads. As a result, the reservoir will require deep foundations to avoid settlement induced damage and provide overturning resistance. We, therefore recommend that the reservoir be supported on auger-cast piles bearing in the glacially consolidated soils. Auger-cast pile recommendations are presented in the following sections. 4.4.1 Auger-Cast Concrete Piles We recommend the use of 24-inch diameter auger-cast concrete piles. The shafts should penetrate the recessional outwash sands to bear in the underlying glacially consolidated deposits encountered at a depth of about 44 feet below the ground surface. It is our understanding that 80 piles will be required to accommodate the loads associated to the proposed structure. Pile rows 1 and 2, drilled to penetrate 2 feet into the glacially consolidated soils (total length of about 46 feet), would be capable of developing allowable capacities of 280 kips each. Pile rows 3, 4 and 5, should be drilled to penetrate 8 feet into the glacially consolidated soils (total length of about 52 feet) and would be capable of developing allowable capacities of 380 kips each. These capacities accounts for the reduction in capacity for shaft groups with a spacing of no less than 3.0 DocuSign Envelope ID: EBD590F4-4493-4D53-B777-F51C36D33E6E May 21, 2018 HWA Project No. 2016-078-21 2016-078 Revised Final Geotechnical Report 10 HWA GEOSCIENCES INC. shaft diameters. A preliminary pile configuration is presented on Figure 5. These depths of embedment into the glacially consolidated soils should be confirmed in the field and the lengths of the piles adjusted to achieve the required embedment depth. We recommend that two sacrificial auger-cast piles be installed near the production pile locations and be tested (in tension) prior the installation of the production piles. We recommend that one of the test piles be advance within the advance outwash deposit and the second test pile within the glacial till deposit. The test results should be used to verify or modify the design of the auger-cast piles, as appropriate. 4.4.2 Construction Considerations The shafts will be drilled through loose to medium dense, recessional outwash and will terminate in the very dense glacially consolidated soils. The contractor could encounter cobbles and or boulders in the shaft excavations. Although not encountered in our borings, large cobbles and boulders are known to exist in glacial deposits. Per the Unified Soil Classification System (USCS), cobbles are defined as a rock with a dimension between 3 and 12 inches; boulders are defined as rock with a minimum dimension of 12 inches. Auger-cast concrete piles are installed by rotating a continuous-flight hollow-stem auger to a pre- determined depth. When the depth is reached, a high strength sand-cement grout is pumped, under controlled pressure, through the center of the shaft as the auger is slowly withdrawn. By maintaining pressure in the grout line and slowly extracting the auger no faster than an equivalent volume of grout is pumped, a continuous column of concrete is formed. The reinforcing cage can then be placed in the column of wet grout. The concrete grout should be allowed to cure a sufficient length of time so that it is self-supporting prior to installing adjacent piles. The quality of auger-cast concrete piles is primarily dependent on the procedures and workmanship of the Contractor who installs them. We recommend that the injection port through which the grout is discharged during the pile pumping procedures be located at the bottom of the auger. A properly functioning pressure gage and pump stroke counter should be provided on the grout pump to assist in monitoring auger-cast pile installation. The counter is used to determine the volume of grout pumped by counting the number of strokes of a displacement-type pump. The pump should be calibrated prior to its use. The pressure gage is used to monitor the pressure of the grout to evaluate the rate at which the auger should be retracted, and if the auger or hoses become plugged. The auger should be withdrawn with slow positive rotation at a slow steady pull and should not be pulled until grout has been pumped a few feet above the tip. Hydraulic controls should be required on the crane supporting the auger so that the auger can be withdrawn in a smooth continuous motion. DocuSign Envelope ID: EBD590F4-4493-4D53-B777-F51C36D33E6E May 21, 2018 HWA Project No. 2016-078-21 2016-078 Revised Final Geotechnical Report 11 HWA GEOSCIENCES INC. The installation of auger-cast concrete piles, including measurement of the volume of grout pumped into each pile, should be monitored on a full-time basis by a geotechnical engineer to verify that they are installed in a satisfactory manner. 4.4.3 Lateral Design Parameters Based on the soil conditions encountered, we recommend the proposed auger-cast piles extend into the very dense, glacial till soils. We understand that the design team desires to use conventional p-y method of lateral analysis (i.e., LPILE). For LPILE analysis, we recommend using the LPILE parameters in Table 3. We recommend a design groundwater table elevation of 177 feet (at the base of the recessional outwash sands). Table 3. Soil Properties for Lateral Shaft Analysis (Static and Seismic) Approx. Soil Unit thickness (feet) Soil Layer Soil Type (p-y model) Unit Wt, (pcf) *1 Effecti ve Unit Wt, (pci) Friction Angle (deg) Undrain ed Shear Strength Cu (psi) p-y Modulus Static, k (pci) p-y Modulus Seismic, k (pci) Strain Factor, ε50 (dim) 44 Recessional Outwash Sand (Reese) 120 0.0694 32 -- 60 60 -- 120 0.0694 32 -- 80 80 -- 20 Glacial Till Sand (Reese) 140 0.0449 40 -- 125 125 -- 140 0.0449 40 -- 125 125 -- Advance Outwash Sand (Reese) 130 0.0391 39 -- 125 125 -- 130 0.0391 39 -- 125 125 -- *1: Unit weight – Water Unit Weight = Effective Unit Weight Boring BH-2 was terminated 73 feet bgs, within the Advance Outwash unit. The p-y curves generated by the lateral parameters provided in Table 3 must be modified by the applicable p-multipliers to account for the group reduction effects. We understand that the minimum center-to-center shaft spacing is 3 shaft diameters, as shown in Figure 5. The p-multipliers for shaft spacing of 4 shaft diameters are provided in the WSDOT GDM (WSDOT, 2015), and included in Table 4. DocuSign Envelope ID: EBD590F4-4493-4D53-B777-F51C36D33E6E May 21, 2018 HWA Project No. 2016-078-21 2016-078 Revised Final Geotechnical Report 12 HWA GEOSCIENCES INC. Table 4. P Multipliers for Center-to-Center Spacing of 3 Shaft Diameters Row P-Multiplier 1 0.8 2 0.4 3 or more 0.3 The same p-multiplier factor should be applied parallel and perpendicular to the group shaft alignment. The following diagram shows how the p-multipliers should be assigned with respect to the load direction and shaft orientation. Parallel Direction Perpendicular Direction 4.5 RETAINING WALLS It is our understanding that site grades will require portions of the existing grade to be cut and/or filled. Therefore, to facilitate grade changes associated with the proposed final grades retaining walls will be required north and south of the tank. Walls design recommendations are provided below. 4.5.1 Earth Pressures and Drainage Requirements We understand that the walls will vary in heights from approximately 3.5 to 8 feet tall. We recommend that these walls be constructed as SEW walls. We assume that the SEW (Structural Earth Wall) wall will conform to one of the current WSDOT pre-approved systems, and that the wall suppliers will design the walls for internal stability. The retaining walls should be designed in accordance with AASHTO Standard Specifications for Highway Bridges. We recommend that each of the walls be designed using the parameters presented in Table 5. It should be noted that no specific geotechnical exploration was conducted at the locations of proposed retaining walls. If subgrade soil conditions (recessional outwash sands) other than those assumed for these locations are encountered, HWA should be notified to modify our design recommendations. DocuSign Envelope ID: EBD590F4-4493-4D53-B777-F51C36D33E6E May 21, 2018 HWA Project No. 2016-078-21 2016-078 Revised Final Geotechnical Report 13 HWA GEOSCIENCES INC. Table 5. Recommended Design Parameters for Retaining Wall Soil Properties Wall Backfill Retained Soil Foundation Soil Unit Weight (pcf) 140 120 120 Friction Angle (deg) 38 32 32 Cohesion (psf) 0 0 0 AASHTO Load Group I (EP+LL) AASHTO Load Group VII (EP+EQ) Allowable Bearing Capacity (psf) 2500 4000 Acceleration Coefficient (g) N/A 0.385 Wall Backfill should consist of Gravel Borrow for Structural Earth Wall (9-03.14(4)) or Gravel Backfill for Walls (9-03.12(2)), per WSDOT Standard Specifications (WSDOT, 2016). 4.5.2 Structural Earth Wall Global Stability Using the computer program SLIDE 5.0, we evaluated static and seismic global stability of each proposed SEW wall assuming a reinforced zone extending approximately 0.7 times the maximum design height of the wall. Analyses were completed utilizing site topography and wall geometry provided to us by MSA. Factors of safety, for static global stability, in excess of 1.5, the minimum required, were calculated given the geologic conditions and a minimum wall embedment of 1 foot. Seismic stability was evaluated using pseudo-static methods to evaluate the response of the slope under earthquake loading. Pseudo-static slope stability analyses model the anticipated earthquake loading as a constant horizontal force applied to the soil mass. For our analyses, we used a horizontal acceleration of 0.19g, which is ½ of the peak ground acceleration (PGA). From our analyses, we conclude that, under a design earthquake, a factor of safety for global stability greater than 1.1 will exist. We conclude from our analyses that global stability will be adequate under static and design seismic loading conditions for walls with a reinforced zone extending behind the wall face at least 0.7 times the maximum design height of the wall and having a minimum wall embedment of 1 foot. 4.5.3 Wall Drainage We understand that the native recessional outwash sands are permeable and are not prone to the buildup of water behind structures in their native configuration. However, the fines within the DocuSign Envelope ID: EBD590F4-4493-4D53-B777-F51C36D33E6E May 21, 2018 HWA Project No. 2016-078-21 2016-078 Revised Final Geotechnical Report 14 HWA GEOSCIENCES INC. top layer of the recessional outwash sands can be smeared across the site during construction, resulting in a tendency to reduce the anticipated permeability of the native soils. To avoid potential unbalanced earth pressures, we recommend that positive drainage should be provided behind the walls to prevent the buildup of hydrostatic pressures behind all subgrade walls. Provisions for permanent drainage of subsurface water should consist of a perforated drain pipe behind and at the base of the wall, embedded in Gravel Backfill for Drains, per WSDOT Standard Specification 9-03.12(4). The drain pipe should be graded to direct water from the backfill and subgrade soils to a suitable outlet. 4.5.4 General Wall Subgrade Preparation Subgrade preparation is important to limit differential settlement of the walls and maintain global stability. All organic material should be removed. Loose or soft soil, defined as being penetrable more than 1 foot with a 1/2-inch diameter rod pushed in under a 150 lb load (T-probe pushed in by hand), should be removed and replaced with structural backfill or be suitably compacted. The area on which the wall will rest should be graded level perpendicular to the wall face and compacted in accordance with WSDOT Standard Specifications (WSDOT, 2016) Section 2-03.3(14)D. It should be noted that 5 to 7 feet of loose/soft silt material was encountered in two of our explorations (BH-1 and BH-2). This material is not suitable for wall subgrade. Therefore, we recommend the over-excavating 1-foot of this material, so the wall is founded on a 1-foot thick leveling pad constructed of compacted Crushed Surfacing Top Course (CSTC) placed over compacted native soils. Fill against an existing slope will require terraced cuts as outlined in WSDOT Standard Specifications (WSDOT, 2016) Section 2-03.3(14), Embankment Construction. We recommend that HWA be present during construction to verify the assumptions made for the foundation of the wall are met and that the walls are constructed in accordance with the approved plans and specifications. The depth and extent of excavation should be determined by the geotechnical engineer on site. 4.6 UTILITIES It is our understanding that water and storm drain utility pipes will consist of ductile iron pipes and will vary in depth between 5 to 8 feet below existing grade. At the location of the Air Gap/Dechlor manhole, two retaining walls are proposed to increase the existing grade by about 8 feet. The loads associated with these walls could induce elastic settlement onto the underlying loose to medium dense recessional outwash sand. These elastic settlements could damage the proposed 12-inch diameter pipe that goes from the Air Gap/Dechlor MH to the storm detention structure. Therefore, we recommend that the mentioned pipe consists of flexible piping material such as fused HDPE. DocuSign Envelope ID: EBD590F4-4493-4D53-B777-F51C36D33E6E May 21, 2018 HWA Project No. 2016-078-21 2016-078 Revised Final Geotechnical Report 15 HWA GEOSCIENCES INC. We anticipate that the soils encountered at the site can be excavated with conventional excavating equipment such as backhoes and track-hoes. 4.6.1 Flexible Utility Connections Some of the proposed utilities are to transition from the reservoir structure to the soils near the structure. We expect that the seismic response of the soil will be different than that of the reservoir structure. Therefore, the buried utilities could undergo seismic displacements that are different from the utilities attached to the structure. To avoid potentially damaging concentration of stresses at these transitions, we recommend the use of flexible connections wherever utilities transition to the proposed structure. 4.6.2 Bedding and Pipe Support We anticipate that soils encountered at the invert elevation of the proposed pipelines at the site will provide suitable support. If organic and/or soft compressible soils are encountered at the base of excavations, these materials should be removed and replaced with compacted granular pipe bedding material. Over-excavation to remove unsuitable soils should extend on either side of the pipe a distance equal to the depth of over-excavation beneath the pipe. General recommendations relative to the bedding of underground utility pipelines include: • Pipe bedding material, placement, and shaping should be in accordance with the project specifications and the pipe manufacturer’s recommendations. • Pipe bedding materials should be placed on relatively undisturbed native soils, or properly compacted fill soils. If the native subgrade soils are disturbed, the disturbed material should be compacted or removed and replaced with compacted bedding material. Pipe bedding should provide a firm, uniform cradle for the pipe. • If the trench bottom encounters very soft, organic-rich, soils, it may be necessary to over- excavate the unsuitable material by a minimum of 12 inches and be replaced with pipe bedding material. In wet conditions, 1¼-inch-minus crushed granular fill may be used to backfill the over-excavated portion of the trench. • Prior to pipe installation, the pipe bedding should be shaped to fit the pipe haunches with reasonable closeness to provide continuous support along the pipe. Backfill around the pipe should be placed in layers and tamped to obtain complete pipe contact. Pipe bedding material should be used as trench backfill to at least 3 inches above the top of the pipe, for the full width of the trench. In areas where a trench box is used, the bedding material should be placed before the trench box is advanced. DocuSign Envelope ID: EBD590F4-4493-4D53-B777-F51C36D33E6E May 21, 2018 HWA Project No. 2016-078-21 2016-078 Revised Final Geotechnical Report 16 HWA GEOSCIENCES INC. 4.6.3 Trench Backfill Trench backfill should consist of structural fill, as specified in Section 4.11. The native soils encountered have a high percentage of fines and should not be use as backfill material. Vibratory compaction should be applied to the backfill for proper compaction. During placement of the initial lifts, the trench backfill material should not be bulldozed into the trench or dropped directly on the pipe. Furthermore, heavy vibratory equipment should not be permitted to operate directly over the pipe until at least 2 feet of backfill has been placed. Trench backfill should be placed in maximum 8-inch loose lifts and compacted to at least 95% of its maximum dry density, as determined using test method ASTM D 1557, Modified Proctor. 4.7 STORMWATER MANAGEMENT It is our understanding that the City would like to utilize onsite infiltration as a means of stormwater management for the Kennydale Reservoir project. On-site stormwater management will be implemented via an open-bottom, below-grade, storm detention system and permeable pavement. To support this design, a Pilot Infiltration Testing (PIT) was performed in general accordance with the King County, Washington, Surface Water Design Manual (King County, 2016). The bottom of the infiltration facility is proposed to be approximately 16 feet below existing ground surface. Ground water was measured in the nearby borehole piezometer (BH-1) about 40 feet bgs. Therefore, the depth to ground water below the proposed pond bottom readily exceeds the minimum 3-foot vertical separation requirement. Also, the minimum requirement of 3 feet of permeable soil beneath the infiltration facility was confirmed by the conditions observed in borehole BH-3 as well as by digging 3 feet deep through the PIT test surface after the test. No perching water was observed when test pitting through the bottom of the PIT. Discharge into the excavation stabilized approximately 5 hours into the test, at a flow rate of 3.75 gallons per minute (gpm). Based on the test results and application of correction factors per the manual, we recommend a long-term infiltration rate of 2.3 in/hr at 16 feet below ground surface. Additionally, it is our understanding that pervious concrete pavement around the water tank will be designed considering stormwater quantity and quality using BMP’s in compliance with City of Renton 2016 Surface Design Manual (RSWDM). The RSWDM requires that runoff from pollution generating surfaces be infiltrated into soils that meet the groundwater protection criteria specified on Section 1.2.8: Core Requirement #8: Water Quality Facilities. To determine if the soils meet the required criteria, HWA performed cation exchange capacity (CEC) and organic content (OC) tests (test results attached) on the subgrade soils beneath the proposed infiltration facility. The results of the laboratory testing are summarized in Table 6, below. DocuSign Envelope ID: EBD590F4-4493-4D53-B777-F51C36D33E6E May 21, 2018 HWA Project No. 2016-078-21 2016-078 Revised Final Geotechnical Report 17 HWA GEOSCIENCES INC. Table 6. Summary of Laboratory Testing Results Sample Designation CEC (meq/cc) OC (% by weight) BH-1, S-4 5 0.5 BH-2, S-7 10 0.6 The CEC and OC test results indicated that the receiving soils exceeded the requirements for treatability for CEC (5 meq/cc) and OC (0.5% by weight). In addition, the infiltration rate determined for the subgrade soils beneath the proposed infiltration facility does not exceed the maximum allowed for treatment of 2.4 in/hr. Therefore, we conclude that soils beneath the proposed infiltration facility meet the criteria required by the Soil Treatment Exemption (No. 4) of Section 1.2.8, of the RSWDM. 4.8 BELOW-GRADE STRUCTURES All below grade structures should be designed with consideration of the anticipated lateral earth pressures that will be applied on the structures. We expect that these buried structures will not be free to yield and will develop at-rest earth pressures upon backfilling. These structures should be designed to resist an equivalent fluid pressure of at least 60 pounds per cubic foot (pcf). These earth pressures assume no accumulation of water behind the wall. Proper wall drainage should be constructed to ensure that hydrostatic pressures do not develop behind the wall structure. Active conditions are expected to develop during earthquake shaking. Under earthquake loading conditions, the buried structures will experience an incremental additional horizontal earth pressure. This increment can be approximated using the Mononobe-Okabe method utilizing 0.5 times the PGA for the site, (0.5)(0.385g) = 0.19g. This results in a design active-plus-seismic earth pressure coefficient Kae = 0.37. For design purposes, a design active-plus-seismic equivalent fluid pressure of 52 pcf may be assumed. The Air Gap/Dechlor Manhole should be designed with consideration of the lateral earth pressures shown in Figure 6. 4.9 HMA PAVEMENT It is our understanding that a 16 to 24 feet-wide access road will be designed to provide access to maintenance vehicles to the reservoir and access to the Fire Station 15, as shown on the Site and Exploration Plan, Figure 2. This access road will consist of heavy duty Hot Mix Asphalt DocuSign Envelope ID: EBD590F4-4493-4D53-B777-F51C36D33E6E May 21, 2018 HWA Project No. 2016-078-21 2016-078 Revised Final Geotechnical Report 18 HWA GEOSCIENCES INC. (HMA). We recommend a new pavement section consisting of 6 inches of HMA over 2 inches of compacted Crushed Surfacing Top Course (CSTC) over 6 inches of compacted Crushed Surfacing Base Course (CSBC), as shown in Table 7. Table 7. Structure Requirements for New HMA Pavement Material Description Minimum Layer Thickness (inches) WSDOT Standard Specification HMA 6 5-04 CSTC 2 9-03.9(3) CSBC 6 9-03.9(3) Structural Fill/Prepared Subgrade Proof-roll 9-03.14(1) If a significant volume of construction traffic (mainly fully-loaded trucks) will operate over the completed base before placement of the surfacing, or if the moisture content of the subgrade is elevated as result of rainfall, then heaving and rutting could occur. In such cases, the thickness of base, or structural fill, should be increased. One to two feet of structural fill/quarry spalls may be required below the CSBC in order to provide a base for the compacted materials above. We recommend that the asphalt layers consist of HMA Class ½-inch. The maximum lift thickness for HMA Class ½-inch is 0.3 feet (or 3.6 inches), as stipulated by WSDOT (WSDOT, 2016). 4.9.1 Placement of HMA Placement of HMA should be in accordance with Section 5-04 of the WSDOT Standard Specifications (WSDOT, 2016). Particular attention should be paid to the following: HMA should not be placed until the engineer has accepted the previously constructed pavement layers. HMA should not be placed on any frozen or wet surface. HMA should not be placed when precipitation is anticipated before the pavement can be compacted, or before any other weather conditions which could prevent proper handling and compaction of HMA. HMA should not be placed when the average surface temperatures are less than 45o F. HMA temperature behind the paver should be in excess of 240o F. Compaction should be completed before the mix temperature drops below 180o F. Comprehensive temperature records should be kept during the HMA placement. DocuSign Envelope ID: EBD590F4-4493-4D53-B777-F51C36D33E6E May 21, 2018 HWA Project No. 2016-078-21 2016-078 Revised Final Geotechnical Report 19 HWA GEOSCIENCES INC. For cold joints, tack coat should be applied to the edge to be joined and the paver screed should be set to overlap the first mat by 1 to 2 inches. 4.9.2 HMA Drainage It is essential to the satisfactory performance of the roadway that good drainage is provided to prevent water ponding alongside the pavement causing saturation of the pavement and subgrade layers. The base layers should be graded to prevent water being trapped within the layer. The surface of the pavement should be sloped to convey water from the pavement to appropriate drainage facilities. 4.10 PERVIOUS CONCRETE PAVEMENT DESIGN It is our understanding that a section of the access road (around the water tank) will consist of pervious concrete pavement, as shown in Figure 2. We understand that this portion of the road will be 9 feet wide and will be used primarily by service vehicles and not by heavy equipment or heavy trucks. It should be noted that sandy silt soils with high percentage of fines were encountered near the ground surface (about 5-7 feet below ground surface) at this site. These soils are not conducive to infiltration. Therefore, we recommend removing the upper fine- grained material (sandy silt soils) to expose the clean native soils. This excavation should be backfilled with permeable ballast, per WSDOT Standard Specification 9-03.9(2) (WSDOT, 2016). The granular material placed underneath the pervious pavement should be should compacted to a dense and unyielding condition. Additionally, it is our understanding that a permeable pavement section was designed for the parking lot of the Fire Station 15 located south of the reservoir. It is our recommendation that heavy traffic should not operate on the pervious pavement, as turning operations are likely to dislodge aggregates from the pavement surface. Unless the pervious pavement section was designed taking this into consideration. In general, pervious pavement sections consist of a wearing course, a choker course, a recharge bed course, and a carefully prepared subgrade. Regardless of the type of wearing course used, the size and composition of the remaining courses are generally the same. Table 8 presents our recommendations for the pervious concrete pavement section around the reservoir (water tank). The following sections provide our recommendations for each component of the pervious pavement section. DocuSign Envelope ID: EBD590F4-4493-4D53-B777-F51C36D33E6E May 21, 2018 HWA Project No. 2016-078-21 2016-078 Revised Final Geotechnical Report 20 HWA GEOSCIENCES INC. Table 8. Structure Requirements for New Pervious PCC Pavement Around Water Tank Material Description Minimum Layer Thickness (inches) WSDOT Standard Specification PCC Wearing Surface 6 5-05 Choker Course (AASHTO No. 57) 1 - Recharge Bed (AASHTO No. 2) Varies (18-36) - Non-Woven Geosynthetic - 9-33.2(1) Table 3 Prepared Subgrade Uncompacted Section 5.05.3 4.10.1 Pervious Portland Cement Concrete Based on the anticipated light loading conditions and the nature of pervious concrete pavement, it is our recommendation that this pavement section consist of a minimum of 6 inches of pervious Portland cement concrete pavement. Pervious Portland cement concrete is typically a proprietary product that is readily available from many local concrete batch plants. In general, the pervious concrete mix uses uniformly graded, crushed coarse aggregate (e.g. meeting AASHTO grading No. 8) with no, or limited use of fine aggregate, and a water to cement ratio ranging from 0.27 to 0.35. The 28-day compressive strength of the mix is typically between 2,500 psi and 4,000 psi with an average modulus of rupture of about 350 to 375 psi. The unit weight of the mix is between 100 and 125 pcf with a porosity of 15% to 25%. The permeability of the hardened product is between 300 and 800 in/hr. We recommend that expansion joints be saw cut into the concrete at spacings of no greater than 12 feet in order to limit post construction cracking. These joints need not be sealed. Maintenance practices for cleaning pervious concrete should be implemented to maintain permeability. Some cleaning techniques are pressure washing, vacuum sweeping and/or a combination of these two methods. 4.10.2 Recharge Bed Design and Subgrade Preparation Recharge beds under pervious pavements should be adequately sized to provide sufficient storage during the 2-year design storm, and should also include an overflow system (or under- drain system) to handle peaks of more intense (25 or 50-year) storms. Typical bed thicknesses range between 1.5 feet and 3 feet. DocuSign Envelope ID: EBD590F4-4493-4D53-B777-F51C36D33E6E May 21, 2018 HWA Project No. 2016-078-21 2016-078 Revised Final Geotechnical Report 21 HWA GEOSCIENCES INC. The drain aggregate in the recharge bed should consist of 1 inch to 1.5 inch crushed, washed drain rock, or 1.5 to 2.5 inch washed crushed base aggregate such as AASHTO No. 2. The coarse gravel should be placed in 8-inch thick (maximum) loose lifts with each layer compacted to an unyielding condition. A design value of 0.3 should be used for the porosity of the base aggregate. A 1-inch-thick choker course consisting of uniformly graded gravel, such as size AASHTO No.57 aggregate, should be placed over the surface of the recharge bed to provide an adequate platform for the porous wearing surface. A nonwoven geotextile meeting the material requirements of WSDOT Standard Specifications (WSDOT, 2016) Section 9-33.1, with the properties listed in Section 9-33.2(1) Table 3 for Separation, should be placed along the sides of the excavation between the native and the drain aggregate to prevent migration of fines into the recharge bed. The nonwoven geotextile should not be placed below the pervious wearing surface over the top of the recharge bed aggregate. Placing nonwoven geotextile below the pervious wearing surface could result in clogging of the geotextile over time, reducing the functionality of the system. 4.11 SITE EARTHWORK RECOMMENDATIONS 4.11.1 Structural Fill and Compaction All fill placed at this site should be considered structural fill. Structural fill materials should consist of clean, free-draining, granular soils free from organic matter or other deleterious materials. The native soils along the project alignment are not suitable for reuse as structural fill for this project. Such imported materials should be less than 4 inches in maximum particle dimension, with less than 7 percent fines (portion passing the U. S. Standard No. 200 sieve), as specified for Gravel Borrow in Section 9-03.14(1) of the WSDOT Standard Specifications (WSDOT, 2016) or Crushed Surfacing Top Course (CSTC) as specified in Section 9-03.9(3) of the WSDOT Standard Specifications (WSDOT, 2016). The fine-grained portion of structural fill soils should be non-plastic. All fill should be placed in lifts and compacted to at least 95 percent of its maximum dry density, as determined using test method ASTM D 1557 (Modified Proctor). The thickness of loose lifts should not exceed 8 inches for heavy weight compactors and 4 inches for hand-operated equipment. The procedure to achieve the specified minimum relative compaction depends on the size and type of compacting equipment, the number of passes, thickness of the layer being compacted, and certain soil properties. We recommend that the appropriate lift thickness, and the adequacy of the subgrade preparation and materials compaction be evaluated by a representative of the geotechnical engineer during construction. A sufficient number of in-place density tests should DocuSign Envelope ID: EBD590F4-4493-4D53-B777-F51C36D33E6E May 21, 2018 HWA Project No. 2016-078-21 2016-078 Revised Final Geotechnical Report 22 HWA GEOSCIENCES INC. be performed as the fill is being placed to verify that the required compaction is achieved. The fill should be probed prior to field density testing to verify that the test is located in an area that is representative of the remainder of the fill. 4.11.2 Temporary Excavations Temporary excavations will be required to construct the proposed tank at the desired elevations. Maintenance of safe working conditions, including temporary excavation stability, is the responsibility of the contractor. In accordance with Part N of Washington Administrative Code (WAC) 296-155, latest revisions, all temporary cuts in excess of 4 feet in height must be either sloped or shored prior to entry by personnel. The existing granular soils on site are generally classified as Type C soils, per WAC 296-155. Where shoring is not used, temporary slopes in Type C soils should be no steeper than 1½H:1V (horizontal: vertical). It is important that the contractor monitors the stability of temporary cut slopes and adjust the construction schedule and slope inclination accordingly. 4.11.3 Wet Weather Earthwork During period of wet weather, even the most permeable soils can become difficult to work and compact. Given that the near surface soils across most of the site consist of recessional outwash sand, we would expect variability in the fines content of the native soil. Soils with higher fines contents will be hard to compact when above a given moisture content (generally about 10 to 12 percent moisture). As a result, the moisture content of these soils may be difficult to control during periods of wet weather. If fill is to be placed or earthwork is to be performed in wet weather or under wet conditions, the following recommendations apply: • Earthwork should be accomplished in small sections to minimize exposure to wet weather. Excavation or the removal of unsuitable soil should be followed promptly by the placement and compaction of a suitable thickness of clean structural fill. The size and type of construction equipment used may need to be limited to prevent soil disturbance; • Material used as structural fill should consist of clean, granular soil, of which not more than 5 percent by dry weight passes the U.S. Standard No. 200 sieve, based on wet sieving the fraction passing the ¾-inch sieve; this is an additional restriction for the structural fill materials described in Section 4.11.1. The fine-grained portion of the structural fill soils should be non-plastic; • The ground surface within the construction area should be sloped and sealed with a smooth drum vibratory roller to promote rapid runoff of precipitation and to prevent ponding of water; DocuSign Envelope ID: EBD590F4-4493-4D53-B777-F51C36D33E6E May 21, 2018 HWA Project No. 2016-078-21 2016-078 Revised Final Geotechnical Report 23 HWA GEOSCIENCES INC. • No soil should be left uncompacted so it can absorb water. Soils which become too wet for compaction should be removed and replaced with clean granular materials; and • Excavation and placement of fill should be observed on a full-time basis by a person experienced in wet weather earthwork to verify that all unsuitable materials are removed and suitable compaction and site drainage is achieved. The above recommendations for wet weather earthwork should be incorporated into the contract specifications. 5.0 CONDITIONS AND LIMITATIONS We have prepared this report for the City of Renton and Murraysmith, for use in design phase of this project. This report should be provided in its entirety to prospective contractors for bidding and estimating purposes; however, the conclusions and interpretations presented herein should not be construed as a warranty of the subsurface conditions. Experience has shown that soil and groundwater conditions can vary significantly over small distances. Inconsistent conditions can occur between explorations that may not be detected by a geotechnical study. If, during future site operations, subsurface conditions are encountered which vary appreciably from those described herein, HWA should be notified for review of the recommendations of this report, and revision of such if necessary. If there is a substantial lapse of time between submission of this report and the start of construction, or if conditions change due to construction operations at or adjacent to the project site, it is recommended that this report be reviewed to determine the applicability of the conclusions and recommendations considering the changed conditions and time lapse. This report is issued with the understanding that it is the responsibility of the owner, or the owners’ representative, to ensure that the information and recommendations contained herein are brought to the attention of the appropriate design team personnel and incorporated into the project plans and specifications, and the necessary steps are taken to see that the contractor and subcontractors carry out such recommendations in the field. HWA is available to monitor construction to evaluate soil and groundwater conditions as they are exposed and verify that subgrade preparation, fill placement and compaction, and pile installation are accomplished in accordance with the project specifications. Within the limitations of scope, schedule and budget, HWA attempted to execute these services in accordance with generally accepted professional principles and practices in the fields of geotechnical engineering and engineering geology at the time the report was prepared. No warranty, express or implied, is made. The scope of our work did not include environmental DocuSign Envelope ID: EBD590F4-4493-4D53-B777-F51C36D33E6E DocuSign Envelope ID: EBD590F4-4493-4D53-B777-F51C36D33E6E May 21, 2018 HWA Project No. 2016-078-21 2016-078 Revised Final Geotechnical Report 25 HWA GEOSCIENCES INC. 6.0 REFERENCES American Association of State Highway and Transportation Officials (AASHTO), 1993, AASHTO Guide for Design of Pavement Structures, American Association of State Highway and Transportation Officials. Booth, D.B. and Wisher, A.P. 2006. Geologic Map of King County 1:100,000 Quadrangles, Washington, Department of Earth and Space Sciences, University of Washington, GeoMapNW. International Code Council, 2012. International Building Code, 2012, published May, 2011, International Code Council, Falls Church, VA. King County Department of Natural Resources and Parks, April 2016. King County, Washington Surface Water Design Manual. Rocscience Inc., 2013. Settle 3D Version 2.018, Computer Software. Tokimatsu, K. and H.B. Seed, 1987. Evaluation of settlements in sands due to earthquake shaking, J. Geot. Engrg., 113 (8), 861-878. USGS Earthquake Hazards Program, 2002. “2002 Interactive Deaggregation”, USGS Earthquake Hazards Program, National Earthquake Hazard Maps, http://eqint.cr.usgs.gov/eq-men/html/deaggint2002. WSDOT, 2015 Geotechnical Design Manual, M 46-03.11. WSDOT, 2016. Standard Specifications for Road, Bridge and Municipal Construction, Washington State Department of Transportation. DocuSign Envelope ID: EBD590F4-4493-4D53-B777-F51C36D33E6E VICINITY MAP KENNYDALE 320 PRESSURE ZONE RESERVOIR RENTON, WASHINGTON 1 2016-078-21 FIGURE NO. PROJECT NO. MAP NOT TO SCALE BASE MAP FROM GOOGLE MAPS DATA © 2016 GOOGLE N © 2016 Microsoft MDA Geospatial Services Inc. Lake Washington Approximate extent of project site DocuSign Envelope ID: EBD590F4-4493-4D53-B777-F51C36D33E6E FIGURE NO. PROJECT NO. SITE AND EXPLORATION PLAN KENNYDALE 320 PRESSURE ZONE RESERVOIR RENTON, WASHINGTON 2 2016-078-21 BH-1 BH-2 BH-3 BH-1 Boring designation and approximate location. (HWA 2016) PT-1 PT-2 BH-4 BH-5 BH-6 BH-4 Boring designation and approximate location. (HWA 2017) Pilot Infiltration Test designation and approximate location. (HWA 2017) PT-1 DocuSign Envelope ID: EBD590F4-4493-4D53-B777-F51C36D33E6E . GEOLOGIC MAP KENNYDALE 320 PRESSURE ZONE RESERVOIR RENTON, WASHINGTON 3 2016-078-21 FIGURE NO. PROJECT NO. MAP NOT TO SCALE N Approximate project site location DocuSign Envelope ID: EBD590F4-4493-4D53-B777-F51C36D33E6E 17517617717817918018118218311/06/16 11/13/16 11/20/16 11/27/16 12/04/16 12/11/16 12/18/16 12/25/16 01/01/17 01/08/17 01/15/17 01/22/17 01/29/17 02/05/17 02/12/17 02/19/17 02/26/17 03/05/17 03/12/17 03/19/17 03/26/17 04/02/17 04/09/17 04/16/17 04/23/17 04/30/17 05/07/17 05/14/17 05/21/17 05/28/17 06/04/17 06/11/17 06/18/17 06/25/17 07/02/17 07/09/17 07/16/17 07/23/17 07/30/17 08/06/17 08/13/17 08/20/17 08/27/17 09/03/1709/10/1709/17/1709/24/1710/01/1710/08/1710/15/1710/22/1710/29/1711/05/1711/12/1711/19/1711/26/1712/03/1712/10/1712/17/1712/24/1712/31/1701/07/1801/14/1801/21/1801/28/18 Ground Water Elevation (ft)Date and TimeGroundwater Elevation from November 11, 2016 to January 01,2018  BH‐1 groundwater elevationBH-01 GROUND WATER ELEVATION DATA42016-078-21FIGURE NO.PROJECT NO.KENNYDALE 320 PRESSURE ZONE RESERVOIRRENTON, WASHINGTON* Based on BH‐1 well surface elvation of 222 feetDocuSign Envelope ID: EBD590F4-4493-4D53-B777-F51C36D33E6E FIGURE NO. PROJECT NO. PRELIMINARY PILE LAYOUT KENNYDALE 320 PRESSURE ZONE RESERVOIR RENTON, WASHINGTON 5 2016-078-21 DocuSign Envelope ID: EBD590F4-4493-4D53-B777-F51C36D33E6E LATERAL EARTH PRESSURES FOR AIR GAP/DECHLOR MH6FIGURE NO.PROJECT NO.2016-078-21DRAWN BY BFMCHECK BY SB/SKDATE05.07.2018H:\HWA GEOTECHNICAL\2016-078-21 KENNYDALE RESERVOIR\HWA 2016-078-21 EP.DWG <Fig 6> Plotted: 5/10/2018 12:34 PMKENNYDALE 320 PRESSURE ZONE RESERVOIRRENTON, WASINGTONNOTES:·All the pressures shown are in the units of pounds per squarefoot (psf).·A factor of safety has not been applied to the recommendearth pressure values.·Surcharge load Q should be equal to factored Dead and LiveLoad including equipment, traffic, etc.STATICSTATIC + SEISMICAT-RESTPRESSUREHYDROSTATICPRESSUREACTIVE + SEISMICPRESSUREHYDROSTATICPRESSUREDocuSign Envelope ID: EBD590F4-4493-4D53-B777-F51C36D33E6E APPENDIX A FIELD EXPLORATION DocuSign Envelope ID: EBD590F4-4493-4D53-B777-F51C36D33E6E A-12016-078-21 Kennydale 320 Pressure Zone Reservoir Renton, Washington LEGEND OF TERMS AND SYMBOLS USED ON EXPLORATION LOGS RELATIVE DENSITY OR CONSISTENCY VERSUS SPT N-VALUE COHESIONLESS SOILS Density Very Loose Loose Medium Dense Very Dense Dense N (blows/ft) 0 to 4 4 to 10 10 to 30 30 to 50 over 50 Approximate Relative Density(%) 0 - 15 15 - 35 35 - 65 65 - 85 85 - 100 COHESIVE SOILS Consistency Very Soft Soft Medium Stiff Stiff Very Stiff Hard N (blows/ft) 0 to 2 2 to 4 4 to 8 8 to 15 15 to 30 over 30 Approximate Undrained Shear Strength (psf) <250 250 - 500 500 - 1000 1000 - 2000 2000 - 4000 >4000 ASTM SOIL CLASSIFICATION SYSTEM MAJOR DIVISIONS Coarse Grained Soils Gravel and Gravelly Soils Clean Gravel (little or no fines) More than 50% of Coarse Fraction Retained on No. 4 Sieve Gravel with Fines (appreciable amount of fines) More than 50% Retained on No. 200 Sieve Size Sand and Sandy Soils Clean Sand (little or no fines) 50% or More of Coarse Fraction Passing No. 4 Sieve Sand with Fines (appreciable amount of fines) Fine Grained Soils Silt and Clay Liquid Limit Less than 50% 50% or More Passing No. 200 Sieve Size Silt and Clay Liquid Limit 50% or More Highly Organic Soils GROUP DESCRIPTIONS GW GP GM GC SW SP SM SC ML CL OL MH CH OH PT Well-graded GRAVEL Poorly-graded GRAVEL Silty GRAVEL Clayey GRAVEL Well-graded SAND Poorly-graded SAND Silty SAND Clayey SAND SILT Lean CLAY Organic SILT/Organic CLAY Elastic SILT Fat CLAY Organic SILT/Organic CLAY PEAT PZOLEGEND 2016-078.GPJ 11/22/16 PROJECT NO.:FIGURE: TEST SYMBOLS GS %F CN TX UC DS M PP TV CBR MD PID AL Grain Size Distribution Percent Fines Well Cap Concrete Seal 5 - Well Casing Bentonite Seal Groundwater Level (measured at time of drilling) Groundwater Level (measured in well after water level stabilized) Slotted Well Casing Consolidation Triaxial Compression Unconfined Compression Direct Shear Resilient Modulus Pocket Penetrometer Approx. Compressive Strength (tsf) Torvane Approximate Shear Strength (tsf) California Bearing Ratio Moisture/Density Relationship < Photoionization Device Reading Atterberg Limits:PL Plastic Limit LL Liquid Limit SAMPLE TYPE SYMBOLS 2.0" OD Split Spoon (SPT) (140 lb. hammer with 30 in. drop) Shelby Tube 3.0" OD Split Spoon with Brass Rings Small Bag Sample Large Bag (Bulk) Sample Core Run Non-standard Penetration Test (with split spoon sampler) COMPONENT PROPORTIONS Very (Clayey, Silty, Sandy, Gravelly) RANGE OF PROPORTIONDESCRIPTIVE TERMS Slightly (Clayey, Silty, Sandy) Sand Backfill GROUNDWATER WELL COMPLETIONS Locking Well Security Casing MOISTURE CONTENT DRY Absence of moisture, dusty, dry to the touch. Clean MOIST Damp but no visible water. WET Visible free water, usually soil is below water table. COMPONENT DEFINITIONS COMPONENT Boulders Cobbles Gravel Coarse gravel Fine gravel Sand Coarse sand Medium sand Fine sand Silt and Clay SIZE RANGE Larger than 12 in 3 in to 12 in 3 in to No 4 (4.5mm) 3 in to 3/4 in 3/4 in to No 4 (4.5mm) No. 4 (4.5 mm) to No. 200 (0.074 mm) No. 4 (4.5 mm) to No. 10 (2.0 mm) No. 10 (2.0 mm) to No. 40 (0.42 mm) No. 40 (0.42 mm) to No. 200 (0.074 mm) Smaller than No. 200 (0.074mm) NOTES: Soil classifications presented on exploration logs are based on visual and laboratory observation in general accordance with ASTM D 2487 and ASTM D 2488. Soil descriptions are presented in the following general order: Density/consistency, color, modifier (if any) GROUP NAME, additions to group name (if any), moisture content. Proportion, gradation, and angularity of constituents, additional comments. (GEOLOGIC INTERPRETATION) Please refer to the discussion in the report text as well as the exploration logs for a more complete description of subsurface conditions. 12% 12 - 30% 30 - 50% 5% Clayey, Silty, Sandy, Gravelly DocuSign Envelope ID: EBD590F4-4493-4D53-B777-F51C36D33E6E S-1 S-2 S-3 S-4 S-5 S-6 S-7 S-8 S-9 S-10 GS GS GS GS ML SM SP 1-2-2 3-7-6 4-6-7 5-7-8 4-5-9 3-5-9 10-19-24 5-7-14 6-12-14 4-9-13 Soft, brown, organic, sandy SILT, moist. (TOPSOIL) Loose, light olive brown, very sandy SILT, moist. Trace coarse sand. Scattered roots and rust mottling. (RECESSIONAL OUTWASH) Alternating bands of medium dense, olive gray and olive brown, silty, fine to medium SAND, moist. Bands are up to 1" in thickness. Trace roots. Medium dense, olive brown, slightly silty, fine to medium SAND, moist. Rust band observed at 8.1'. Medium dense, olive brown, very silty, fine to medium SAND, moist. Band of olive brown, silty fine sand from 12.9'-13.4'. Medium dense, olive gray, clean, fine to medium SAND, moist. Bands of olive brown, silty fine sand up to 2" thick throughout sample. Dense, gray, clean, fine to coarse SAND, moist. Becomes more dry with fine gravels increasing in abundance starting at 18.6'. Possibly overstated blow counts due to gravel in sampler. Medium dense, olive gray, fine to medium SAND, moist. Trace coarse sand and fine gravel. Trace rust mottling. Medium dense, gray, clean, fine to coarse SAND with fine gravel, moist. Medium dense, gray, clean, fine to medium SAND, moist. Trace fine gravel. One bad of coarse sand from 28.7' to 28.8'. 0 20 40 60 80 100 Water Content (%) Plastic Limit (140 lb. weight, 30" drop) Blows per foot (blows/6 inches)USCS SOIL CLASSDESCRIPTION SAMPLE TYPESAMPLE NUMBERPEN. RESISTANCEOTHER TESTSPIEZOMETERStandard Penetration Test A-2SYMBOLSCHEMATIC01020304050 Liquid Limit BORING: BH-1 PAGE: 1 of 2 Water Content (%) Natural Water ContentNOTE: This log of subsurface conditions applies only at the specified location and on the date indicated and therefore may not necessarily be indicative of other times and/or locations. PZO-DSM 2016-078.GPJ 1/3/17 FIGURE:PROJECT NO.:2016-078-21 Renton, Washington Kennydale 320 Pressure Zone ReservoirDEPTH(feet)0 5 10 15 20 25 30 ELEVATION(feet)DATE COMPLETED: 11/10/2016 DRILLING COMPANY: Environmental Drilling Inc. DRILLING METHOD: B-61 Truck Rig with 4.25" ID continuous flight HSA LOCATION: 55.2' west of eastern fence line; 54.7' south of northern fence line DATE STARTED: 11/10/2016 SAMPLING METHOD: SPT with auto-hammer LOGGED BY: B. Salazar DocuSign Envelope ID: EBD590F4-4493-4D53-B777-F51C36D33E6E S-11 S-12 S-13 S-14 S-15 SM 10-15-18 10-12-16 15-28-27 50/6" 12-37-50/4" Dense, olive gray, slightly silty, fine to medium SAND, moist. Medium dense, olive gray, clean, fine to medium SAND, moist. Becomes fine sand at 38.5'. Driller notes hard drilling at 40'. Very dense, olive brown, silty, fine to medium SAND with minor fine gravel, moist. Faint rust mottling. (GLACIAL TILL) Very dense, olive brown, silty, fine to medium SAND, moist. Very dense, olive brown, silty, fine to medium SAND with gravel, moist. Boring terminated at 51.3 feet. No groundwater observed while conducting this exploratory boring. Piezo well installed. Well tag #BIZ317. Groundwater observed at 46.6 feet bgs on 11/11/2016. 0 20 40 60 80 100 Water Content (%) Plastic Limit (140 lb. weight, 30" drop) Blows per foot (blows/6 inches)USCS SOIL CLASSDESCRIPTION SAMPLE TYPESAMPLE NUMBERPEN. RESISTANCEOTHER TESTSPIEZOMETERStandard Penetration Test A-2SYMBOLSCHEMATIC01020304050 Liquid Limit BORING: BH-1 PAGE: 2 of 2 Water Content (%) Natural Water ContentNOTE: This log of subsurface conditions applies only at the specified location and on the date indicated and therefore may not necessarily be indicative of other times and/or locations. PZO-DSM 2016-078.GPJ 1/3/17 FIGURE:PROJECT NO.:2016-078-21 Renton, Washington Kennydale 320 Pressure Zone ReservoirDEPTH(feet)30 35 40 45 50 55 60 ELEVATION(feet)DATE COMPLETED: 11/10/2016 DRILLING COMPANY: Environmental Drilling Inc. DRILLING METHOD: B-61 Truck Rig with 4.25" ID continuous flight HSA LOCATION: 55.2' west of eastern fence line; 54.7' south of northern fence line DATE STARTED: 11/10/2016 SAMPLING METHOD: SPT with auto-hammer LOGGED BY: B. Salazar >> >> >> DocuSign Envelope ID: EBD590F4-4493-4D53-B777-F51C36D33E6E GS GS GS GS %F S-1 S-2 S-3 S-4A S-4B S-5 S-6 S-7A S-7B S-8 S-9 S-10 Soft, brown, organic, sandy SILT, moist. (TOPSOIL) Medium dense, light olive brown, very sandy SILT, moist. Trace coarse sand and fine gravel. Roots. Rust mottling around gravels. (RECESSIONAL OUTWASH) Medium dense, olive brown, very silty, fine to medium SAND, moist. Rust mottling and trace roots throughout sample. Scattered lenses of olive gray clean fine to medium sand. Medium dense, olive brown, silty, fine to medium SAND, dry/moist. Trace roots. Medium dense, olive brown, silty, fine to medium SAND, moist. Becomes clean at 11.0'. Medium dense, olive gray, fine to medium, poorly graded SAND, with silt, moist. Medium dense, olive gray, fine to medium SAND with trace fine gravel and silt, moist. One silty fine sand lens from 16.0 to 16.2'. Medium dense, olive brown, sandy SILT, moist. Thinly bedded. Medium dense, olive gray, clean, fine to coarse SAND with fine gravel, moist. Grain size increases with depth. Medium dense, olive gray, clean, fine to medium SAND, moist. Trace coarse sand and fine gravel. Poor recovery during sample. Medium dense, gray, fine to medium SAND with fine gravel, moist. Gravel increases in abundance with depth. 2-5-14 7-9-9 7-9-8 6-7-9 4-7-7 5-5-9 5-7-14 4-6-11 5-8-11 6-11-15 ML SM SP SM ML SP BORING-DSM 2016-078.GPJ 1/3/17 FIGURE:PROJECT NO.:2016-078-21 Renton, Washington Kennydale 320 Pressure Zone Reservoir BH-2 PAGE: 1 of 3(blows/6 inches)GROUNDWATERPEN. RESISTANCELiquid Limit (140 lb. weight, 30" drop) Blows per foot A-3 Standard Penetration Test NOTE: This log of subsurface conditions applies only at the specified location and on the date indicated DESCRIPTION OTHER TESTSPlastic Limit BORING: and therefore may not necessarily be indicative of other times and/or locations.SYMBOL0 10 20 30 40 50 0 20 40 60 80 100SAMPLE TYPESAMPLE NUMBERNatural Water ContentUSCS SOIL CLASSWater Content (%)DEPTH(feet)0 5 10 15 20 25 30 ELEVATION(feet)DATE COMPLETED: 11/9/2016 DRILLING COMPANY: Environmental Drilling Inc. DRILLING METHOD: B-61 Truck Rig with 4.25" ID continuous flight HSA LOCATION: 71.6' west of eastern fence line; 72.0' south of northern fence line DATE STARTED: 11/9/2016 SAMPLING METHOD: SPT with auto-hammer LOGGED BY: B. Salazar DocuSign Envelope ID: EBD590F4-4493-4D53-B777-F51C36D33E6E S-11 S-12 S-13A S-13B S-14 S-15 S-16 Dense, olive gray, clean, fine to coarse SAND, moist. Becomes fine to medium. Becomes wet. Dense, olive brown, silty SAND, moist. Trace fine gravel. More gravel in sampler tip. (GLACIAL TILL) Drillers report gravelly drilling at 45' Hard, olive brown, fine sandy SILT, moist. Rust mottling. Trace coarse sand. Very dense, gray, silty SAND with gravel, moist. Very dense, gray, silty, fine SAND with trace coarse sand and fine gravel, moist. Becomes olive brown from 53.5' to 54'. Very dense, gray, silty SAND with gravel, moist. Weathered sandstone in sampler from 57.5' to 58'. 10-17-27 9-14-16 13-14-22 11-25-43 21-32-50/6" 33-50/3" SP SM SM BORING-DSM 2016-078.GPJ 1/3/17 FIGURE:PROJECT NO.:2016-078-21 Renton, Washington Kennydale 320 Pressure Zone Reservoir BH-2 PAGE: 2 of 3(blows/6 inches)GROUNDWATERPEN. RESISTANCELiquid Limit (140 lb. weight, 30" drop) Blows per foot A-3 Standard Penetration Test NOTE: This log of subsurface conditions applies only at the specified location and on the date indicated DESCRIPTION OTHER TESTSPlastic Limit BORING: and therefore may not necessarily be indicative of other times and/or locations.SYMBOL0 10 20 30 40 50 0 20 40 60 80 100SAMPLE TYPESAMPLE NUMBERNatural Water ContentUSCS SOIL CLASSWater Content (%)DEPTH(feet)30 35 40 45 50 55 60 ELEVATION(feet)DATE COMPLETED: 11/9/2016 DRILLING COMPANY: Environmental Drilling Inc. DRILLING METHOD: B-61 Truck Rig with 4.25" ID continuous flight HSA LOCATION: 71.6' west of eastern fence line; 72.0' south of northern fence line DATE STARTED: 11/9/2016 SAMPLING METHOD: SPT with auto-hammer LOGGED BY: B. Salazar >> >> >> DocuSign Envelope ID: EBD590F4-4493-4D53-B777-F51C36D33E6E S-17 S-18 S-19 Very dense, olive gray to gray, silty, fine SAND with gravel, moist. Trace coarse sand above sampler tip. Hard, olive brown, sandy SILT, moist. Rust at lower contact. Drillers noted earier drilling at 64'. (ADVANCE OUTWASH) Very dense, gray, silty, fine SAND with trace gravel, moist. Angled clean sand layer at 68.5' Very dense, gray, gravelly SAND with silt, wet. Poor recovery. Boring terminated at 73 feet. Groundwater observed at 43.5 feet while conducting this exploratory boring. 50/6" 14-21-28 50/6" SM SP BORING-DSM 2016-078.GPJ 1/3/17 FIGURE:PROJECT NO.:2016-078-21 Renton, Washington Kennydale 320 Pressure Zone Reservoir BH-2 PAGE: 3 of 3(blows/6 inches)GROUNDWATERPEN. RESISTANCELiquid Limit (140 lb. weight, 30" drop) Blows per foot A-3 Standard Penetration Test NOTE: This log of subsurface conditions applies only at the specified location and on the date indicated DESCRIPTION OTHER TESTSPlastic Limit BORING: and therefore may not necessarily be indicative of other times and/or locations.SYMBOL0 10 20 30 40 50 0 20 40 60 80 100SAMPLE TYPESAMPLE NUMBERNatural Water ContentUSCS SOIL CLASSWater Content (%)DEPTH(feet)60 65 70 75 80 85 90 ELEVATION(feet)DATE COMPLETED: 11/9/2016 DRILLING COMPANY: Environmental Drilling Inc. DRILLING METHOD: B-61 Truck Rig with 4.25" ID continuous flight HSA LOCATION: 71.6' west of eastern fence line; 72.0' south of northern fence line DATE STARTED: 11/9/2016 SAMPLING METHOD: SPT with auto-hammer LOGGED BY: B. Salazar >> >> DocuSign Envelope ID: EBD590F4-4493-4D53-B777-F51C36D33E6E GS GS GS GS S-1 S-2 S-3 S-4 S-5 S-6 S-7 S-8 S-9 Soft, dark brown, organic, sandy SILT, moist. Roots. (TOPSOIL) Loose, olive brown, very silty, fine to medium SAND, moist. Trace fine gravels. Rust mottling throughout. Roots. (RECESSIONAL OUTWASH) Medium dense, olive brown, silty, fine to medium SAND, moist. Roots, scattered rust bands. Medium dense, olive gray, clean SAND, moist. Trace silt. Thinly bedded. Scattered rust bands. Becomes slightlty silty. Bedding becomes massive. Medium dense, olive gray, silty, fine to medium SAND, moist. Scattered rust mottling observed. Silt band observed from 21'-21.3'. Some fine gravels from 21.3'-21.5'. Boring terminated at 21.5 feet. No groundwater observed while conducting this exploratory boring. 1-2-1 2-4-5 4-7-10 5-6-7 5-7-8 4-5-6 4-7-10 4-5-7 4-6-8 SM SP SM SM BORING-DSM 2016-078.GPJ 1/3/17 FIGURE:PROJECT NO.:2016-078-21 Renton, Washington Kennydale 320 Pressure Zone Reservoir BH-3 PAGE: 1 of 1(blows/6 inches)GROUNDWATERPEN. RESISTANCELiquid Limit (140 lb. weight, 30" drop) Blows per foot A-4 Standard Penetration Test NOTE: This log of subsurface conditions applies only at the specified location and on the date indicated DESCRIPTION OTHER TESTSPlastic Limit BORING: and therefore may not necessarily be indicative of other times and/or locations.SYMBOL0 10 20 30 40 50 0 20 40 60 80 100SAMPLE TYPESAMPLE NUMBERNatural Water ContentUSCS SOIL CLASSWater Content (%)DEPTH(feet)0 5 10 15 20 25 30 ELEVATION(feet)DATE COMPLETED: 11/9/2016 DRILLING COMPANY: Environmental Drilling Inc. DRILLING METHOD: B-61 Truck Rig with 4.25" ID continuous flight HSA LOCATION: 43.5' east of western fence line; 75.9' south of northern fence line DATE STARTED: 11/9/2016 SAMPLING METHOD: SPT with auto-hammer LOGGED BY: B. Salazar DocuSign Envelope ID: EBD590F4-4493-4D53-B777-F51C36D33E6E S-1 S-2 S-3 S-4 GS+HYD GS+HYD SM SM SP SM 10 10 Medium dense, light olive brown, silty, fine SAND, dry to moist, trace coarse sand, scattered roots. (RECESSIONAL OUTWASH) Stiff, olive brown, very silty, fine SAND, grades to very silty, fine SAND, moist, non-plastic, with scattered fine to large gravel and cobbles. Medium dense, olive brown, slightly silty, fine to medium SAND, moist, olive greyish brown at 8'. Medium dense, olive greyish brown, slightly silty to clean, fine to medium SAND, moist, some caving at 13'. Renton, Washington 2016-078-21 FIGURE: SMART TP 2016-078.GPJ 8/31/17 Kennydale 320 Pressure Zone Reservoir PAGE: 1 of 2 TP-1 LOG OF TEST PIT PROJECT NO.: and therefore may not necessarily be indicative of other times and/or locations. NOTE: This log of subsurface conditions applies only at the specified location and on the date indicated A-5 EXCAVATION COMPANY: EXCAVATING EQUIPMENT:SAMPLE NUMBERLOGGED BY: A. York DATE COMPLETED: 7/25/17 LOCATION: 75' S of N fence; 40' E of W fence SYMBOLOTHER TESTSUSCS SOIL CLASSMOISTUE CONTENT (%)SAMPLE TYPEDEPTH (feet)0 5 10 15 DESCRIPTION TEST PIT PHOTO DocuSign Envelope ID: EBD590F4-4493-4D53-B777-F51C36D33E6E S-5 GS+HYDSP SM 7 Medium dense, olive greyish brown, slightly silty to clean, fine to medium SAND, moist. Test pit terminated at 19 feet. Pilot infiltration test performed at 16 feet. Renton, Washington 2016-078-21 FIGURE: SMART TP 2016-078.GPJ 8/31/17 Kennydale 320 Pressure Zone Reservoir PAGE: 2 of 2 TP-1 LOG OF TEST PIT PROJECT NO.: and therefore may not necessarily be indicative of other times and/or locations. NOTE: This log of subsurface conditions applies only at the specified location and on the date indicated A-5 EXCAVATION COMPANY: EXCAVATING EQUIPMENT:SAMPLE NUMBERLOGGED BY: A. York DATE COMPLETED: 7/25/17 LOCATION: 75' S of N fence; 40' E of W fence SYMBOLOTHER TESTSUSCS SOIL CLASSMOISTUE CONTENT (%)SAMPLE TYPEDEPTH (feet)15 20 25 30 DESCRIPTION TEST PIT PHOTO DocuSign Envelope ID: EBD590F4-4493-4D53-B777-F51C36D33E6E APPENDIX B LABORATORY TESTING DocuSign Envelope ID: EBD590F4-4493-4D53-B777-F51C36D33E6E 2016-078 Revised Final Geotechnical Report B-1 HWA GEOSCIENCES INC. APPENDIX B LABORATORY TESTING Representative soil samples obtained from the explorations were placed in plastic bags to prevent loss of moisture and transported to our Bothell, Washington, laboratory for further examination and testing. Laboratory tests were conducted on selected soil samples to characterize relevant engineering and index properties of the site soils. Laboratory testing was conducted as described below: MOISTURE CONTENT OF SOIL: The moisture content of selected soil samples (percent by dry mass) was determined in general accordance with ASTM D 2216. The results are shown at the sampled intervals on the appropriate summary logs in Appendix A. PARTICLE SIZE ANALYSIS OF SOILS: Selected samples were tested to determine the particle (grain) size distribution of material in general accordance with ASTM D 422. The results are summarized on the attached Particle Size Analysis of Soils reports, Figures B-1 through B-4, which also provide information regarding the classification of the sample, and the moisture content at the time of testing. DocuSign Envelope ID: EBD590F4-4493-4D53-B777-F51C36D33E6E 0 10 20 30 40 50 60 70 80 90 100 0.0010.010.1110 Coarse #60#40 PARTICLE-SIZE ANALYSIS OF SOILS METHOD ASTM D422 66.2 16.4 12.3 #20 Fine Coarse SYMBOL Gravel % 3"1-1/2"PERCENT FINER BY WEIGHT#4 #200 0.0 Sand % (ML) Light olive brown, sandy SILT with organics (SM) Light olive brown, silty SAND (SM) Olive brown, silty SAND Fines % 24 19 10 GRAIN SIZE IN MILLIMETERS 50 SAMPLE S-1 S-2 S-3 2.5 - 4.0 5.0 - 6.5 7.5 - 9.0 #10 33.7 83.6 87.7 30 CLASSIFICATION OF SOIL- ASTM D2487 Group Symbol and Name U.S. STANDARD SIEVE SIZES SAND CLAY BH-1 BH-1 BH-1 SILT 3/4" GRAVEL 0.05 5/8" 70 #100 0.5 50 Medium Fine 3/8" 5 PI 90 10 % MC LL PLDEPTH ( ft.) B-1 0.00050.005 2016-078-21PROJECT NO.: HWAGRSZ 2016-078.GPJ 8/31/17 FIGURE: Kennydale 320 Pressure Zone Reservoir Renton, Washington DocuSign Envelope ID: EBD590F4-4493-4D53-B777-F51C36D33E6E 0 10 20 30 40 50 60 70 80 90 100 0.0010.010.1110 Coarse #60#40 PARTICLE-SIZE ANALYSIS OF SOILS METHOD ASTM D422 33.6 57.3 34.3 #20 Fine Coarse SYMBOL Gravel % 3"1-1/2"PERCENT FINER BY WEIGHT#4 #200 0.2 6.8 0.6 Sand % (SM) Light olive brown, silty SAND (ML) Light olive brown, sandy SILT (SM) Light olive brown, silty SAND Fines % 12 16 10 GRAIN SIZE IN MILLIMETERS 50 SAMPLE S-5 S-1 S-2 12.5 - 14.0 2.5 - 4.0 5.0 - 6.5 #10 66.3 35.9 65.1 30 CLASSIFICATION OF SOIL- ASTM D2487 Group Symbol and Name U.S. STANDARD SIEVE SIZES SAND CLAY BH-1 BH-2 BH-2 SILT 3/4" GRAVEL 0.05 5/8" 70 #100 0.5 50 Medium Fine 3/8" 5 PI 90 10 % MC LL PLDEPTH ( ft.) B-2 0.00050.005 2016-078-21PROJECT NO.: HWAGRSZ 2016-078.GPJ 8/31/17 FIGURE: Kennydale 320 Pressure Zone Reservoir Renton, Washington DocuSign Envelope ID: EBD590F4-4493-4D53-B777-F51C36D33E6E 0 10 20 30 40 50 60 70 80 90 100 0.0010.010.1110 Coarse #60#40 PARTICLE-SIZE ANALYSIS OF SOILS METHOD ASTM D422 17.9 8.3 #20 Fine Coarse SYMBOL Gravel % 3"1-1/2"PERCENT FINER BY WEIGHT#4 #200 0.1 Sand % (SM) Light olive brown, silty SAND (SP-SM) Olive brown, poorly graded SAND with silt (ML) Olive brown, sandy SILT Fines % 11 7 24 GRAIN SIZE IN MILLIMETERS 50 SAMPLE S-4A S-5 S-7A 10.0 - 11.0 12.5 - 14.0 17.5 - 18.3 #10 82.1 91.7 30 CLASSIFICATION OF SOIL- ASTM D2487 Group Symbol and Name U.S. STANDARD SIEVE SIZES SAND CLAY BH-2 BH-2 BH-2 SILT 3/4" GRAVEL 0.05 5/8" 70 #100 0.5 50 Medium Fine 3/8" 5 PI 90 10 % MC LL PLDEPTH ( ft.) B-3 0.00050.005 2016-078-21PROJECT NO.: HWAGRSZ 2016-078.GPJ 8/31/17 FIGURE: Kennydale 320 Pressure Zone Reservoir Renton, Washington DocuSign Envelope ID: EBD590F4-4493-4D53-B777-F51C36D33E6E 0 10 20 30 40 50 60 70 80 90 100 0.0010.010.1110 Coarse #60#40 PARTICLE-SIZE ANALYSIS OF SOILS METHOD ASTM D422 33.4 13.8 14.9 #20 Fine Coarse SYMBOL Gravel % 3"1-1/2"PERCENT FINER BY WEIGHT#4 #200 6.5 Sand % (SM) Light olive brown, silty SAND (SM) Light olive brown, silty SAND (SM) Olive brown, silty SAND Fines % 18 10 6 GRAIN SIZE IN MILLIMETERS 50 SAMPLE S-2 S-3 S-4 2.5 - 4.0 5.0 - 6.5 7.5 - 9.0 #10 60.1 86.2 85.1 30 CLASSIFICATION OF SOIL- ASTM D2487 Group Symbol and Name U.S. STANDARD SIEVE SIZES SAND CLAY BH-3 BH-3 BH-3 SILT 3/4" GRAVEL 0.05 5/8" 70 #100 0.5 50 Medium Fine 3/8" 5 PI 90 10 % MC LL PLDEPTH ( ft.) B-4 0.00050.005 2016-078-21PROJECT NO.: HWAGRSZ 2016-078.GPJ 8/31/17 FIGURE: Kennydale 320 Pressure Zone Reservoir Renton, Washington DocuSign Envelope ID: EBD590F4-4493-4D53-B777-F51C36D33E6E 0 10 20 30 40 50 60 70 80 90 100 0.0010.010.1110 Coarse #60#40 PARTICLE-SIZE ANALYSIS OF SOILS METHOD ASTM D422 10.4 47.7 11.8 #20 Fine Coarse SYMBOL Gravel % 3"1-1/2"PERCENT FINER BY WEIGHT#4 #200 6.5 Sand % (SP-SM) Olive brown, poorly graded SAND with silt (SM) Olive-brown, silty SAND (SP-SM) Olive-brown, poorly graded SAND with silt Fines % 7 10 10 GRAIN SIZE IN MILLIMETERS 50 SAMPLE S-6 S-2 S-3 12.5 - 14.0 3.8 - 4.8 7.0 - 8.0 #10 89.6 45.8 88.2 30 CLASSIFICATION OF SOIL- ASTM D2487 Group Symbol and Name U.S. STANDARD SIEVE SIZES SAND CLAY BH-3 TP-1 TP-1 SILT 3/4" GRAVEL 0.05 5/8" 70 #100 0.5 50 Medium Fine 3/8" 5 PI 90 10 % MC LL PLDEPTH ( ft.) B-5 0.00050.005 2016-078-21PROJECT NO.: HWAGRSZ 2016-078.GPJ 8/31/17 FIGURE: Kennydale 320 Pressure Zone Reservoir Renton, Washington DocuSign Envelope ID: EBD590F4-4493-4D53-B777-F51C36D33E6E 0 10 20 30 40 50 60 70 80 90 100 0.0010.010.1110 Coarse #60#40 PARTICLE-SIZE ANALYSIS OF SOILS METHOD ASTM D422 5.3 #20 Fine Coarse SYMBOL Gravel % 3"1-1/2"PERCENT FINER BY WEIGHT#4 #200 0.2 Sand % (SP-SM) Dark olive-brown, poorly graded SAND with silt Fines % 7 GRAIN SIZE IN MILLIMETERS 50 SAMPLE S-5 16.0 - 17.0 #10 94.5 30 CLASSIFICATION OF SOIL- ASTM D2487 Group Symbol and Name U.S. STANDARD SIEVE SIZES SAND CLAY TP-1 SILT 3/4" GRAVEL 0.05 5/8" 70 #100 0.5 50 Medium Fine 3/8" 5 PI 90 10 % MC LL PLDEPTH ( ft.) B-6 0.00050.005 2016-078-21PROJECT NO.: HWAGRSZ 2016-078.GPJ 8/31/17 FIGURE: Kennydale 320 Pressure Zone Reservoir Renton, Washington DocuSign Envelope ID: EBD590F4-4493-4D53-B777-F51C36D33E6E HWA GEOSCIENCES 21312 30TH DRIVE SE, STE 110 BOTHELL , WA 98021 5/1/2018 Soil BH-1 S-4 S18-07063 Date Received: Grower: Sampled By: Field: Laboratory #: Test Results Customer Account #: Customer Sample ID: Other Tests: Cation Exchange meq/100gCEC 5.0 pH 1:1 E.C. 1:1 m.mhos/cm Est Sat Paste E.C. m.mhos/cm Effervescence Ammonium - N mg/kg %0.5Organic Matter W.B. $26.00This is your Invoice #: List Cost:KEBReviewed by:S18-07063 Account #188200 We make every effort to provide an accurate analysis of your sample. For reasonable cause we will repeat tests, but because of factors beyond our control in sampling procedures and the inherent variability of soil, our liability is limited to the price of the tests. Recommendations are to be used as general guides and should be modified for specific field conditions and situations. Note: "u" indicates that the element was analyzed for but not detected DocuSign Envelope ID: EBD590F4-4493-4D53-B777-F51C36D33E6E HWA GEOSCIENCES 21312 30TH DRIVE SE, STE 110 BOTHELL , WA 98021 5/1/2018 Soil BH-2 S-3 S18-07064 Date Received: Grower: Sampled By: Field: Laboratory #: Test Results Customer Account #: Customer Sample ID: Other Tests: Cation Exchange meq/100gCEC 10.0 pH 1:1 E.C. 1:1 m.mhos/cm Est Sat Paste E.C. m.mhos/cm Effervescence Ammonium - N mg/kg %0.6Organic Matter W.B. $26.00This is your Invoice #: List Cost:KEBReviewed by:S18-07064 Account #188200 We make every effort to provide an accurate analysis of your sample. For reasonable cause we will repeat tests, but because of factors beyond our control in sampling procedures and the inherent variability of soil, our liability is limited to the price of the tests. Recommendations are to be used as general guides and should be modified for specific field conditions and situations. Note: "u" indicates that the element was analyzed for but not detected DocuSign Envelope ID: EBD590F4-4493-4D53-B777-F51C36D33E6E APPENDIX C ADDITIONAL EXPLORATIONS DocuSign Envelope ID: EBD590F4-4493-4D53-B777-F51C36D33E6E A-12016-136-21 Renton Fire Statioin 15 Renton, Washington SYMBOLS USED ON EXPLORATION LOGS LEGEND OF TERMS AND to 30 over 30 Approximate Undrained Shear Strength (psf) <250 250 - No. 4 Sieve Sand with Fines (appreciable amount of fines) amount of fines) More than 50% Retained on No. 200 Sieve Size Sand and Sandy Soils Clean Gravel (little or no fines) More than 50% of Coarse Fraction Retained on No. 4 Sieve Gravel with SM SC ML MH CH OH RELATIVE DENSITY OR CONSISTENCY VERSUS SPT N-VALUE Very Loose Loose Medium Dense Very Dense Dense N (blows/ft) 0 to 4 4 to 10 10 to 30 30 to 50 over 50 Approximate Relative Density(%) 0 -15 15 -35 35 -65 65 -85 85 -100 COHESIVE SOILS Consistency Very Soft Soft Medium Stiff Stiff Very Stiff Hard N (blows/ft) 0 to 2 2 to 4 4 to 8 8 to 15 15 Clean Sand (little or no fines) 50% or More of Coarse Fraction Passing Fine Grained Soils Silt and Clay Liquid Limit Less than 50% 50% or More Passing No. 200 Sieve Size Silt and Clay Liquid Limit 50% or More 500 500 -1000 1000 -2000 2000 -4000 >4000 DensityDensity USCS SOIL CLASSIFICATION SYSTEM Coarse Grained Soils Gravel and Gravelly Soils Highly Organic Soils GROUP DESCRIPTIONS Well-graded GRAVEL Poorly-graded GRAVEL Silty GRAVEL Clayey GRAVEL Well-graded SAND Poorly-graded SAND Silty SAND Clayey SAND SILT Lean CLAY Organic SILT/Organic CLAY Elastic SILT Fat CLAY Organic SILT/Organic CLAY PEAT MAJOR DIVISIONS GW SP CL OL PT GP GM GC SW COHESIONLESS SOILS Fines (appreciable LEGEND 2016-136.GPJ 5/2/17 PROJECT NO.:FIGURE: Coarse sand Medium sand SIZE RANGE Larger than 12 in Smaller than No. 200 (0.074mm) Gravel time of drilling) Groundwater Level (measured in well or AL CBR CN Atterberg Limits: LL = Liquid Limit California Bearing Ratio Consolidation Resilient Modulus Photoionization Device Reading Pocket Penetrometer Specific Gravity Triaxial Compression Torvane 3 in to 12 in 3 in to No 4 (4.5mm) No. 4 (4.5 mm) to No. 200 (0.074 mm) COMPONENT DRY Absence of moisture, dusty, dry to the touch. MOIST Damp but no visible water. WET Visible free water, usually soil is below water table. Boulders Cobbles Coarse gravel Fine gravel Sand MOISTURE CONTENT COMPONENT PROPORTIONS Fine sand Silt and Clay 5 - 12% PROPORTION RANGE DESCRIPTIVE TERMS Clean Slightly (Clayey, Silty, Sandy) 30 - 50% Components are arranged in order of increasing quantities. Very (Clayey, Silty, Sandy, Gravelly) 12 - 30%Clayey, Silty, Sandy, Gravelly open hole after water level stabilized) Groundwater Level (measured at 3 in to 3/4 in 3/4 in to No 4 (4.5mm) No. 4 (4.5 mm) to No. 10 (2.0 mm) No. 10 (2.0 mm) to No. 40 (0.42 mm) No. 40 (0.42 mm) to No. 200 (0.074 mm) PL = Plastic Limit DD DS GS K MD MR PID PP SG TC TV Dry Density (pcf) Direct Shear Grain Size Distribution Permeability Approx. Shear Strength (tsf) Percent Fines%F Moisture/Density Relationship (Proctor) Approx. Compressive Strength (tsf) Unconfined CompressionUC (140 lb. hammer with 30 in. drop) Shelby Tube Small Bag Sample Large Bag (Bulk) Sample Core Run Non-standard Penetration Test 2.0" OD Split Spoon (SPT) NOTES: Soil classifications presented on exploration logs are based on visual and laboratory observation. Density/consistency, color, modifier (if any) GROUP NAME, additions to group name (if any), moisture content. Proportion, gradation, and angularity of constituents, additional comments. (GEOLOGIC INTERPRETATION) Please refer to the discussion in the report text as well as the exploration logs for a more complete description of subsurface conditions. Soil descriptions are presented in the following general order: < 5% 3-1/4" OD Split Spoon with Brass Rings (3.0" OD split spoon) TEST SYMBOLS SAMPLE TYPE SYMBOLS GROUNDWATER SYMBOLS COMPONENT DEFINITIONS DocuSign Envelope ID: EBD590F4-4493-4D53-B777-F51C36D33E6E GS GS GS %F GS S-1 S-2 S-3 S-4 S-5 S-6 S-7 S-8 S-9 S-10 Soft, dark brown, sandy SILT with organics, wet. (TOPSOIL) Medium stiff, brown, sandy SILT, moist. Sand is fine to medium. Rootlets, rust mottling, and scattered anoxic decomposition (black spots) visible throughout. (RECESSIONAL OUTWASH) Loose, brown, very sandy SILT, moist. Rootlets and rust banding observed. Trace coarse sand. Loose, olive brown, very silty, fine to coarse SAND, moist. Rust staining. Silty sand layer from 8.5 to 9.0 feet. Medium dense, olive brown, silty, medium to coarse SAND with trace gravel, moist. Gravel is subrounded to subangular. Medium dense, olive brown, silty, fine to medium SAND, moist. Becomes wet. Scattered rust bands observed. Becomes olive brown to olive gray, and moist. Medium dense, olive gray, fine clean SAND, moist. Rust band observed at 20.5'. Becomes fine to medium. Becomes mostly fine sand. Olive brown silty sand layers at 31.0'. Scattered oxidation bands. Boring terminated at 31.5 feet. No groundwater observed while conducting this exploratory boring. 1-1-3 3-1-3 4-5-4 5-6-7 5-7-8 5-8-9 5-6-10 5-6-7 6-9-11 6-8-9 ML SM SP BORING-DSM 2016-136.GPJ 8/31/17 FIGURE:PROJECT NO.:2016-136-21 Renton, Washington Renton Fire Statioin 15 BH-4 PAGE: 1 of 1(blows/6 inches)GROUNDWATERPEN. RESISTANCELiquid Limit (140 lb. weight, 30" drop) Blows per foot A-2 Standard Penetration Test NOTE: This log of subsurface conditions applies only at the specified location and on the date indicated DESCRIPTION OTHER TESTSPlastic Limit BORING: and therefore may not necessarily be indicative of other times and/or locations.SYMBOL0 10 20 30 40 50 0 20 40 60 80 100SAMPLE TYPESAMPLE NUMBERNatural Water ContentUSCS SOIL CLASSWater Content (%)DEPTH(feet)0 5 10 15 20 25 30 35 ELEVATION(feet)DATE COMPLETED: 3/29/2017 DRILLING COMPANY: Environmental Drilling Inc. DRILLING METHOD: B-61 Truck Rig with 4.25" IC Continuous Flight HSA LOCATION: 80.0' North of South fence; 53.9' West of East fence DATE STARTED: 3/29/2017 SAMPLING METHOD: SPT with auto-hammer LOGGED BY: B. Salazar SURFACE ELEVATION: Approx. 212 feet DocuSign Envelope ID: EBD590F4-4493-4D53-B777-F51C36D33E6E GS GS GS GS GS %F GS %F S-1 S-2 S-3 S-4 S-5 S-6 S-7 S-8 Soft, dark brown, sandy SILT with organics, wet. (TOPSOIL) Loose, dark yellowish brown, very silty SAND, moist. Rust mottling throughout sample. One gravel (1" diameter) observed at 3.0'. (RECESSIONAL OUTWASH) Medium dense, dark yellowish brown, silty, fine to medium SAND, wet. Rust bands observed throughout sample. Trace wood and some gravels at 6.0'. Clean sand band at 5.5' and 6.2'. Stiff, dark yellowish brown, very sandy SILT, moist. Bands of medium sand observed from 10.5' to 11.0'. Medium dense, dark brown, silty, fine to medium SAND, moist. Rust band observed at 13.8'. Medium dense, olive brown, slightly silty, fine to medium SAND, moist. Rust band observed at 15.3'. 2-3-5 2-3-8 3-5-8 2-3-6 4-7-11 6-6-8 5-8-8 5-7-9 SM ML SM SP SM BORING-DSM 2016-136.GPJ 5/2/17 FIGURE:PROJECT NO.:2016-136-21 Renton, Washington Renton Fire Statioin 15 BH-5 PAGE: 1 of 2(blows/6 inches)GROUNDWATERPEN. RESISTANCELiquid Limit (140 lb. weight, 30" drop) Blows per foot A-3 Standard Penetration Test NOTE: This log of subsurface conditions applies only at the specified location and on the date indicated DESCRIPTION OTHER TESTSPlastic Limit BORING: and therefore may not necessarily be indicative of other times and/or locations.SYMBOL0 10 20 30 40 50 0 20 40 60 80 100SAMPLE TYPESAMPLE NUMBERNatural Water ContentUSCS SOIL CLASSWater Content (%)DEPTH(feet)0 5 10 15 20 25 ELEVATION(feet)DATE COMPLETED: 3/29/2017 DRILLING COMPANY: Environmental Drilling Inc. DRILLING METHOD: B-61 Truck Rig with 4.25" IC Continuous Flight HSA LOCATION: 46.1' East of West fence; 77.2' North of South fence DATE STARTED: 3/29/2017 SAMPLING METHOD: SPT with auto-hammer LOGGED BY: B. Salazar SURFACE ELEVATION: Approx. 209 feet DocuSign Envelope ID: EBD590F4-4493-4D53-B777-F51C36D33E6E S-9 S-10 S-11 S-12 S-13 Becomes wet. Becomes saturated and fine at 32.5'. (WEATHERED TILL) Band of loose, gray, silty fine SAND, moist, from 37.5' to 38.0'. Trace coarse sand grains observed. Very stiff, olive brown, slightly sandy SILT, moist, from 38.0' to 38.5'. Rust banding throughout. Dense, olive brown, medium to coarse SAND with gravel, wet. Gravel is subrounded to subangular. Becomes silty fine SAND from 42.5' to 43.0. Rust banding observed. Boring terminated at 44 feet. No groundwater observed while conducting this exploratory boring (perched water possible at 32.5'). 6-9-11 3-5-7 5-11-13 9-26-28 7-10-17 SP SM SP BORING-DSM 2016-136.GPJ 5/2/17 FIGURE:PROJECT NO.:2016-136-21 Renton, Washington Renton Fire Statioin 15 BH-5 PAGE: 2 of 2(blows/6 inches)GROUNDWATERPEN. RESISTANCELiquid Limit (140 lb. weight, 30" drop) Blows per foot A-3 Standard Penetration Test NOTE: This log of subsurface conditions applies only at the specified location and on the date indicated DESCRIPTION OTHER TESTSPlastic Limit BORING: and therefore may not necessarily be indicative of other times and/or locations.SYMBOL0 10 20 30 40 50 0 20 40 60 80 100SAMPLE TYPESAMPLE NUMBERNatural Water ContentUSCS SOIL CLASSWater Content (%)DEPTH(feet)25 30 35 40 45 50 ELEVATION(feet)DATE COMPLETED: 3/29/2017 DRILLING COMPANY: Environmental Drilling Inc. DRILLING METHOD: B-61 Truck Rig with 4.25" IC Continuous Flight HSA LOCATION: 46.1' East of West fence; 77.2' North of South fence DATE STARTED: 3/29/2017 SAMPLING METHOD: SPT with auto-hammer LOGGED BY: B. Salazar >> SURFACE ELEVATION: Approx. 209 feet DocuSign Envelope ID: EBD590F4-4493-4D53-B777-F51C36D33E6E GS GS GS GS S-1 S-2 S-3 S-4 S-5 S-6 S-7 S-8 S-9 S-10 Soft, dark brown, sandy SILT with organics, wet. (TOPSOIL) Medium stiff, olive brown, sandy SILT, wet. Rust bands observed throughout sample. (RECESSIONAL OUTWASH) Driller notes gravelly drilling action at 4.5'. Loose, dark yellowish brown, very sandy SILT, moist to wet. Trace organics. Rust bands observed. Loose, dark yellowish brown, slightly silty, fine to medium SAND, moist. One oxidation band at 8.0'. Becomes medium dense. Medium dense, grayish brown, slightly silty, fine to medium SAND, moist. Becomes lighter olive gray. Driller notes gravelly drilling action at 29'. Trace coarse sand in sampler tip (31.5'). Boring terminated at 31.5 feet. No groundwater observed while conducting this exploratory boring. 2-3-3 2-2-4 4-4-5 5-6-7 5-6-8 4-6-6 3-3-7 4-6-10 3-6-8 8-11-14 ML SM SP SM BORING-DSM 2016-136.GPJ 5/2/17 FIGURE:PROJECT NO.:2016-136-21 Renton, Washington Renton Fire Statioin 15 BH-6 PAGE: 1 of 1(blows/6 inches)GROUNDWATERPEN. RESISTANCELiquid Limit (140 lb. weight, 30" drop) Blows per foot A-4 Standard Penetration Test NOTE: This log of subsurface conditions applies only at the specified location and on the date indicated DESCRIPTION OTHER TESTSPlastic Limit BORING: and therefore may not necessarily be indicative of other times and/or locations.SYMBOL0 10 20 30 40 50 0 20 40 60 80 100SAMPLE TYPESAMPLE NUMBERNatural Water ContentUSCS SOIL CLASSWater Content (%)DEPTH(feet)0 5 10 15 20 25 30 35 ELEVATION(feet)DATE COMPLETED: 3/29/2017 DRILLING COMPANY: Environmental Drilling Inc. DRILLING METHOD: B-61 Truck Rig with 4.25" IC Continuous Flight HSA LOCATION: 138.9' North of South fence; 35.0' West of East fence DATE STARTED: 3/29/2017 SAMPLING METHOD: SPT with auto-hammer LOGGED BY: B. Salazar SURFACE ELEVATION: Approx. 214 feet DocuSign Envelope ID: EBD590F4-4493-4D53-B777-F51C36D33E6E S-1 S-2 S-3 S-4 GS + HYD GS + HYD GS + HYD SM ML SP SM 15 9 17 Medium dense, light olive brown, silty, fine to medium SAND, dry, scattered roots. (TOPSOIL) Medium dense, olive brown, sandy SILT, moist, trace coarse grains, trace fine to large gravel. (RECESSIONAL OUTWASH) Large boulder partially exposed in west wall of test pit. Medium dense, olive brown, slightly silty, fine to medium SAND, moist. Test pit terminated at 13' feet. Small scale pilot infiltration test performed at 7 feet. Renton, Washington 2016-136-21 FIGURE: SMART TP 2016-136.GPJ 8/31/17 Renton Fire Statioin 15 PAGE: 1 of 1 TP-2 LOG OF TEST PIT PROJECT NO.: and therefore may not necessarily be indicative of other times and/or locations. NOTE: This log of subsurface conditions applies only at the specified location and on the date indicated A-5 EXCAVATION COMPANY: Kelly's Excavating EXCAVATING EQUIPMENT:SAMPLE NUMBERLOGGED BY: A. York DATE COMPLETED: 7/25/17 LOCATION: 120' N of S fence; 40' E of W fence.SYMBOLOTHER TESTSUSCS SOIL CLASSMOISTUE CONTENT (%)SAMPLE TYPEDEPTH (feet)0 5 10 15 DESCRIPTION TEST PIT PHOTO DocuSign Envelope ID: EBD590F4-4493-4D53-B777-F51C36D33E6E