Loading...
HomeMy WebLinkAboutRS_TalbotSub_Improvements_Geotechnical_Engineering_Services_Report_220218_v1Earth Science + Technology                                           Geotechnical Engineering Services Revised Report Talbot Substation Improvements Renton, Washington for Puget Sound Energy February 1, 2017                                             Geotechnical Engineering Services Revised Report Talbot Substation Improvements Renton, Washington for Puget Sound Energy February 1, 2017   Plaza 600 Building 600 Stewart Street, Suite 1700  Seattle, Washington 98101 206.728.2674  February 1, 2017 | Page i File No. 0186-953-00 Table of Contents INTRODUCTION AND SCOPE .................................................................................................................................... 1  FIELD EXPLORATION AND LABORATORY TESTING ................................................................................................ 1  Field Explorations ................................................................................................................................................. 1  Laboratory Testing ............................................................................................................................................... 2  SITE CONDITIONS ..................................................................................................................................................... 2  Geology ................................................................................................................................................................. 2  Surface Conditions............................................................................................................................................... 2  Subsurface Conditions ........................................................................................................................................ 2  CONCLUSIONS AND RECOMMENDATIONS ............................................................................................................ 3  Critical Areas ........................................................................................................................................................ 3  Earthquake Engineering ...................................................................................................................................... 3  2015 IBC Seismic Design Information ........................................................................................................ 3  Shallow and Mat Foundations ............................................................................................................................ 4  General .......................................................................................................................................................... 4  Bearing Pressure ........................................................................................................................................... 4  Embedment ................................................................................................................................................... 5  Settlement ..................................................................................................................................................... 5  Lateral Resistance ........................................................................................................................................ 5  Construction Considerations ........................................................................................................................ 5  Drilled Shafts ........................................................................................................................................................ 6  General .......................................................................................................................................................... 6  Axial Capacity ................................................................................................................................................ 6  Lateral Capacity ............................................................................................................................................ 6  Drilled Shaft Settlement ............................................................................................................................... 6  Construction Considerations ........................................................................................................................ 6  Retaining Walls .................................................................................................................................................... 7  General .......................................................................................................................................................... 7  Infiltration ............................................................................................................................................................. 7  Stormwater Pond ................................................................................................................................................. 7  Earthwork ............................................................................................................................................................. 7  Clearing .......................................................................................................................................................... 7  Subgrade Preparation ................................................................................................................................... 7  Erosion and Sedimentation Control ............................................................................................................. 7  Structural Fill ................................................................................................................................................. 8  Weather Considerations ............................................................................................................................... 9  Temporary Slopes ......................................................................................................................................... 9  LIMITATIONS .......................................................................................................................................................... 10  REFERENCES ........................................................................................................................................................ 10      February 1, 2017 | Page ii File No. 0186-953-00 LIST OF FIGURES Figure 1. Vicinity Map Figure 2. Site Plan Figure 3. Spread Footing Capacity APPENDICES Appendix A. Field Explorations and Laboratory Testing Figure A-1 – Key to Exploration Logs Figures A-2 through A-8 – Logs of Borings Figures A-9 and A-10 – Sieve Analysis Results Appendix B. Report Limitations and Guidelines for Use February 1, 2017 | Page 1 File No. 0186-953-00 INTRODUCTION AND SCOPE This report summarizes the results of GeoEngineers, Inc.’s (GeoEngineers) geotechnical engineering services for the proposed improvements to the existing Puget Sound Energy (PSE) Talbot substation. The site is located west of Beacon Way South in Renton, Washington. The site is shown in relation to the surrounding area on the Vicinity Map, Figure 1, and the Site Plan, Figure 2. We provided a draft version of this report dated November 3, 2014 and final versions dated July 15, 2015 and December 5, 2016. This revised final report provides updated seismic design recommendations for the 2015 International Building Code (IBC) per City of Renton review comments and supersedes our previous reports as described. The 2012 and 2015 IBC seismic design parameters are identical and there are no changes in our conclusions and recommendations other than the referenced IBC. We understand PSE is planning several phases of work at the existing 230-kV substation. Phase 1 involves the replacement of the existing 230 kV transformer located in the middle of the existing substation. The replacement transformer will be supported on a mat foundation. We understand Phase 1 began permitting at the end of 2014 and that the construction has been completed. In 2014, the plan for Phase 2 involved grading to expand the substation to the east, toward Beacon Way South and the Bonneville Power Administration (BPA) 230-kV Maple Valley substation located on the east side of Beacon Way South. Phase 2 also includes construction of new 230-kV dead-end towers as well as support of light equipment. The dead-end towers may be supported on either mat foundations or on drilled shafts. We understand that Phase 2 was scaled back from what was originally planned in 2014 and the substation footprint will not be expanded. We have left recommendations related to the expansion in our report for documentation purposes. We understand that stormwater infiltration is not planned at the site, based on the mapped soil conditions. However, a stormwater detention pond is planned southeast of the existing substation yard. Our geotechnical engineering services were completed in general accordance with our proposal dated August 19, 2014. Our scope of work included: ■ Completing seven borings at the site; ■ Completing laboratory testing on selected soil samples from the borings; ■ Providing geotechnical conclusions and recommendations for the proposed improvements; and ■ Preparing this report. FIELD EXPLORATION AND LABORATORY TESTING Field Explorations The subsurface conditions at the site were evaluated by completing seven borings (GEI-1 through GEI-7) to depths of 16½ to 31½ feet below existing site grades. The approximate locations of the borings are shown on the Site Plan, Figure 2. A detailed description of the field exploration program is presented in Appendix A. February 1, 2017 | Page 2 File No. 0186-953-00 Laboratory Testing Soil samples were obtained during the exploration program and taken to GeoEngineers’ laboratory for further evaluation. Selected samples were tested for the determination of percent fines, moisture content, and grain size distribution (sieve analysis). A description of the laboratory testing and the test results are presented in Appendix A or on the exploration logs, as appropriate. SITE CONDITIONS Geology We reviewed available geologic maps, including the “Geologic map of the Renton quadrangle, King County, Washington” (D.R. Mullineaux, 1965) and the “Geologic Map of King County, Washington” (D. B. Booth et al. 2007). The soils mapped in the project vicinity are predominantly glacial till (Qvt), but include localized areas of ice-contact glacial deposits (Qvi) overlying the till. Glacial till typically consists of a dense to very dense heterogeneous mixture of sand, gravel, cobbles and occasional boulders in a silt and clay matrix that were deposited beneath a glacier. A zone of weathered till typically overlies the glacial till to depths of several feet below the ground surface. The ice-contact deposits tend to be similar in character to the till, but are less dense. Advance outwash is interpreted below the glacial till, based on the subsurface explorations and the geologic maps. Advance outwash generally consists of dense to very dense sand and gravel deposited by streams and rivers issuing from advancing ice sheets and subsequently overridden by a glacier. Surface Conditions The existing substation is bounded by Beacon Way South to the east, and undeveloped properties to the north, west and south. The substation is accessed by a gravel driveway off Puget Drive SE and connects to the south side of the existing substation. The substation yard is relatively flat and is surfaced with yard rock. Transmission lines generally run east and west from the substation. These include two sets of lines that connect this substation with the BPA Maple Valley substation to the east. The topography in the area of the proposed expansion is hummocky and irregular and is about 10 feet higher than the substation and approximately 15 feet higher than Beacon Way South. Vegetation in the expansion area consists of deciduous trees near the southeast corner of the existing substation and brush and blackberries in the other undeveloped areas. There is a city of Seattle water main that runs along Beacon Way South and an underground cable that connects the PSE and BPA substations. The approximate locations of the water main and underground cable are shown on the Site Plan, Figure 2. Other utilities may be present. Subsurface Conditions We explored subsurface conditions at the substation site by drilling seven borings (GEI-1 through GEI-7) at the locations shown on the Site Plan, Figure 2. Appendix A presents details of the field exploration and laboratory testing programs, including logs of borings. February 1, 2017 | Page 3 File No. 0186-953-00 Borings GEI-1 through GEI-4 were completed inside the existing substation and encountered approximately 2 to 7 feet of fill overlying glacial till. The fill generally consisted of loose sand and silty sand with variable gravel content. The glacial till generally consisted of dense to very dense silty sand with variable gravel content and extended to depths of 7 to 23 feet. Advance outwash consisting of very dense sand was encountered below the glacial till in all four borings and extended to the depths explored (21½ to 31½ feet). Borings GEI-5 through GEI-7 were completed in the area of the proposed expansion and encountered approximately 2 to 7 feet of fill consisting of loose sand and organic-rich topsoil and duff overlying glacial till. The glacial till generally consisted of dense to very dense silty sand with variable gravel content and extended to depths of 8 to 23 feet. Advance outwash consisting over very dense sand was encountered in all three borings below the glacial till and extended to the depths explored (16½ to 31½ feet). Groundwater was not encountered during drilling, as noted on the exploration logs. These observations represent a short-term condition that may not be representative of the long-term groundwater conditions at the site. Groundwater conditions observed during drilling should be considered approximate. Groundwater level is anticipated to vary as a function of precipitation, season and other factors. CONCLUSIONS AND RECOMMENDATIONS Critical Areas We reviewed the City of Renton online maps with regard to geologic critical areas including coal mine, erosion, flood, landslide and steep slope hazard areas. The site is not mapped in erosion or flood hazard areas. The site is mapped in a moderate coal mine hazard area. However, based on the depth of historical coal mining activity and the relatively shallow depth of the proposed improvements, it is our opinion there is a low coal mine hazard at the site. The site is mapped in a 25 to 40 percent steep slope area and in a moderate landslide hazard area. It is our opinion that the proposed improvements will not adversely affect the stability of the slopes in or around the site. Based on our evaluation it is our opinion the soils underlying the substation site have a low risk of liquefying under the design earthquake event. It is also our opinion that soils underlying the site have a low risk of lateral spread and earthquake-induced slope movement. The site is approximately 5 miles south of the Seattle Fault Zone, which is thought to have a recurrence interval on the order of 1,000 years. Based on the distance from the nearest mapped fault, it is our opinion there is a low risk of fault rupture at the site. Earthquake Engineering 2015 IBC Seismic Design Information We recommend the 2015 International Building Code (IBC) parameters for Soil Profile Type, short period spectral response acceleration (SS), 1-second period spectral response acceleration (S1), and Seismic Coefficients FA and FV presented in the following table:   February 1, 2017 | Page 4 File No. 0186-953-00 2015 IBC PARAMETERS 2015 IBC Parameter Recommended Value Soil Profile Type C Short Period Spectral Response Acceleration, SS (percent g) 141.3 1-Second Period Spectral Response Acceleration, S1 (percent g) 52.8 Seismic Coefficient, FA 1.00 Seismic Coefficient, FV 1.30 Peak Ground Acceleration, PGA (percent g) 58.0 Note: The above spectral response accelerations are based on data from the United States Geologic Survey (USGS) National Seismic Hazard Mapping Project. Shallow and Mat Foundations General It is our opinion the proposed structures (replacement 230 kV transformer, breakers, switches and other electrical equipment) may be supported on conventional spread footings or mat foundations bearing on either dense to very dense soils where present at foundation depth, or on a minimum of 2 feet of compacted structural fill in areas of loose to medium dense soils present at foundation depth. Due to space limitations, we understand drilled shafts are preferred for support of the dead-end towers. Our recommendations for drilled shaft foundations are discussed in the “Drilled Shafts” section. Bearing Pressure Allowable Stress Design (ASD). Spread footings may be designed using an allowable soil bearing pressure of 3,000 pounds per square foot (psf). Mat foundations may be designed for an allowable bearing pressure of 1,500 psf. The allowable soil bearing pressures apply to the total of dead and long-term live loads and may be increased by up to one-third for transient loads such as wind or seismic forces. A subgrade modulus of 180 pounds per cubic inch (pci) may be used for the design of mat foundations. Load and Resistance Factor Design (LRFD). A bearing capacity chart for spread footings is presented in Figure 3. We recommend the LRFD resistance factors listed in the table below be used when evaluating strength, service and extreme limit states for spread footings. The chart is based on a 5-foot wide footing with varying lengths and may conservatively be used for wider footings. The chart was developed in accordance with American Associate of State and Highway Transportation Officials (AASHTO) methods, in conjunction with Washington State Department of Transportation (WSDOT) standards, as summarized in the WSDOT Geotechnical Design Manual. LRFD SPREAD FOOTING RESISTANCE FACTORS Limit State Resistance Factor  Shear Resistance to Sliding Bearing Passive Pressure Resistance to Sliding Strength 0.8 0.45 0.5 Service 1.0 1.0 1.0 Extreme 0.9 0.9 0.9 February 1, 2017 | Page 5 File No. 0186-953-00 Embedment In general, we recommend that the bottom of foundations be embedded at least 24 inches below the lowest adjacent grade for frost protection. The foundation embedment depth may be reduced to 18 inches for small, lightly loaded footings where frost action will not affect equipment performance, or an additional 6-inch-thick layer of gravel that is not susceptible to frost may be placed below the foundations to achieve an embedment of 24 inches. The gravel should meet the requirements of “yard course” surfacing material presented in the “Structural Fill” section of this report. Settlement Provided all loose soil is removed and the subgrade is prepared as recommended under the “Construction Considerations” section below, we estimate that the total settlement of shallow foundations will be on the order of ½ to 1 inch, with the higher end of that settlement range anticipated in the southwest corner of the substation that is underlain by looser soils. The settlements will occur rapidly, essentially as loads are applied. Differential settlements between comparably loaded foundations are expected to be less than ½ inch. Lateral Resistance Lateral foundation loads may be resisted by passive resistance on the sides of foundations and by friction on the base of the foundations. For foundations supported on native soils or on structural fill placed and compacted in accordance with our recommendations, the allowable frictional resistance may be computed using a coefficient of friction of 0.4 applied to vertical dead-load forces. The allowable passive resistance may be computed using an equivalent fluid density of 250 pounds per cubic foot (pcf) (triangular distribution) if these elements are poured directly against compacted native soils or surrounded by compacted structural fill. The structural fill should extend out from the face of the foundation element for a distance at least equal to three times the height of the element and be compacted to at least 95 percent of the maximum dry density (MDD). The above coefficient of friction and passive equivalent fluid density values incorporate a factor of safety of about 1.5. Construction Considerations Following excavation for foundations, we recommend the condition of each footing excavation be observed by a qualified geotechnical engineer to evaluate if the work is completed in accordance with our recommendations and that the subsurface conditions are as anticipated. Areas of loose or soft soils present at the foundation subgrade elevation should be overexcavated to a maximum depth of 2 feet and replaced with compacted structural fill. In such instances, the zone of structural fill should extend laterally beyond the footing edges a horizontal distance at least equal to the thickness of the fill. A geotextile separator fabric may be used at the base of the overexcavation if loose/soft soils extend below the depth of the overexcavation. February 1, 2017 | Page 6 File No. 0186-953-00 Drilled Shafts General The proposed new 230-kV dead-end towers as well as lightly-loaded equipment may be supported on drilled shafts. We recommend that the drilled shafts extend to a depth of at least 15 feet below the existing ground surface. We should review the final dead-end tower locations when available and provide modifications to these recommendations if appropriate. Axial Capacity The applied axial loads on the drilled shafts for the dead-end towers are generally very small in comparison to the applied overturning moments, resulting from the tension in the wires along with possible ice and wind loading. The axial capacity of the drilled shafts in compression will be developed primarily from friction and end bearing in the medium dense to dense soils. Provided the drilled shafts are embedded at least 15 feet below the existing ground surface and into dense soils at the tip elevation, we anticipate that the allowable axial capacity for shafts at least 3 feet in diameter will be greater than 100 kips. Lateral Capacity The design of the drilled shafts will be governed by the lateral loads on the structures. The lateral capacity of the drilled shafts will develop from the stiffness of the drilled shaft and the lateral resistance of the soil surrounding the drilled shaft. We anticipate that the shafts will be designed using the L-PILETM program. For evaluation of the lateral load behavior of the drilled shafts, the parameters in the tables below can be used as input soil parameters for the L-PILETM program. The table below may conservatively be used for all the drilled shafts. LATERAL PILE ANALYSIS INPUT PARAMETERS Soil Parameter Layer 1 (fill) Layer 2 (glacial till) Layer 3 (advance outwash) Depth (ft) 0-7 7-10 10-30 Soil Type (p-y curve model) Sand (Reese) Sand (Reese) Sand (Reese) Effective Unit Weight (lb/ft3) 125 135 135 Friction Angle (degrees) 32 38 38 p-y Modulus, k (lb/in3) 25 200 150 Drilled Shaft Settlement We estimate that post-construction settlement of drilled shaft foundations, designed and installed as recommended, will be on the order of ½ inch or less. Maximum differential settlement of similarly loaded shaft foundations should be less than about one-half the post-construction settlement. Most of this settlement will occur rapidly as loads are applied. Construction Considerations Temporary casing may be required to keep the drilled holes open while drilling through the zones of sandier soils. The contractor may attempt to drill the holes without casing but should have temporary casing available for use if sloughing and caving occurs. Although not encountered in our explorations, cobbles and February 1, 2017 | Page 7 File No. 0186-953-00 boulders may be present. The excavation contractor should be prepared for these conditions. Groundwater was not encountered in our explorations. However, as discussed above, groundwater may be present depending on the conditions at the time of construction and again the contractor should be prepared to deal with these conditions. We recommend that the drilled shaft foundation excavations be observed by GeoEngineers. Retaining Walls General We anticipate retaining walls may be used in conjunction with fill and cut slopes for grade transitions in the area of the substation expansion. Based on the available space, we anticipate concrete block walls (gravity and/or reinforced) will be the preferred wall type. This type of retaining structure is moderately settlement-sensitive, and suitable foundation support is important. We anticipate that some overexcavation of loose soils will be required to achieve suitable foundation support. We can provide recommendations for design of retaining walls once the wall geometries are better defined. Infiltration It may be possible to design stormwater facilities for infiltration, provided the base of the facilities extends to the advance outwash. This may be impractical considering the grades at the site, but we can provide infiltration recommendations if this appears feasible. Stormwater Pond We understand the stormwater pond is planned with 2H:1V (horizontal:vertical) side slopes and a depth of up to 7 feet in the middle. We recommend the side slopes be protected from erosion. Earthwork We understand that earthwork was planned as part of Phase 2 of this project but is no longer anticipated. Regardless, our recommendations for earthwork are presented below. Clearing Removal and demolition of existing site improvements and structures associated with the existing substation should include removal of foundation elements. Existing voids or new depressions created during demolition and site preparation should be cleaned of loose soil or debris and backfilled with compacted structural fill. Subgrade Preparation New foundation subgrade areas should be evaluated after site grading and foundation excavation is completed. Probing should be used to evaluate the subgrade; soft areas noted during probing should be overexcavated and replaced with compacted structural fill as described in the “Shallow and Mat Foundations” section. Erosion and Sedimentation Control Potential sources or causes of erosion and sedimentation depend upon construction methods, slope length and gradient, amount of soil exposed and/or disturbed, soil type, construction sequencing and weather. February 1, 2017 | Page 8 File No. 0186-953-00 Temporary erosion protection should be used and maintained in areas with exposed or disturbed soils to help reduce the potential for erosion and reduce transport of sediment to adjacent areas and receiving waters. Temporary erosion protection should include the construction of a silt fence around the perimeter of the work area prior to the commencement of grading activities. Permanent erosion protection should be provided by re-establishing vegetation or surfacing with rock. Until the permanent erosion protection is established and the site is stabilized, site monitoring should be performed by qualified personnel to evaluate the effectiveness of the erosion control measures and repair and/or modify them as appropriate. Provisions for modifications to the erosion control system based on monitoring observations should be included in the erosion and sedimentation control plan. Structural Fill Materials Materials used for support of structures or pavements or for utility trench backfill are classified as structural fill for the purpose of this report. Structural fill material quality varies depending upon its use as described below: 1. On-site soils may be used as structural fill to support substation equipment provided it can be appropriately moisture conditioned to achieve the required compaction. If on-site soils cannot be moisture-conditioned, imported gravel borrow for support of substation equipment should conform to PSE Base Course Aggregate Specification 1275.1310 as described in the following table: BASE COURSE GRADATION US Standard Sieve Size Percent Passing (by weight) 3 inch 100 ¾ inch 70-90 ⅜ inch 60-80 ¼ inch 50-70 U.S. No. 40 < 30 U.S. No. 200 < 5 2. Structural fill placed as “yard course crushed aggregate” surfacing material should be angular crushed rock conforming to PSE Specification 1275.1330 as described in the following table: YARD COURSE GRADATION US Standard Sieve Size Percent Passing (by weight) 1½ inches 100 1 inch 60 to 100 ¾ or ⅝ inch 0 to 35 ⅜ inch 0 to 5 February 1, 2017 | Page 9 File No. 0186-953-00 On-site Soils The on-site soils generally contain a significant amount of fines and are moisture sensitive. These soils generally meet the criteria for common borrow and are suitable for use as structural fill only if construction takes place during the drier summer months. Additional considerations for wet weather construction are presented below in the “Weather Considerations” section. Fill Placement and Compaction Criteria Structural fill should be mechanically compacted to a firm, non-yielding condition. In general, structural fill should be placed in loose lifts not exceeding 8 to 10 inches in thickness. Each lift should be conditioned to the proper moisture content and compacted to the specified density before placing subsequent lifts. Structural fill should be compacted to the following criteria: ■ Structural fill placed below foundations or to establish yard subgrade should be compacted to at least 95 percent of the MDD estimated in accordance with ASTM D 1557. We recommend that a representative from our firm be present during probing of the exposed subgrade soils in structure areas prior to the placement of structural fill and during the placement of structural fill. Our representative would evaluate the adequacy of the subgrade soils and identify areas needing further work, perform in-place moisture-density tests in the fill to evaluate if the work is being done in accordance with the compaction specifications, and advise on any modifications to procedures that may be appropriate for the prevailing conditions. Weather Considerations The on-site soils contain a sufficient percentage of fines (silt) to be moisture sensitive. If the moisture content of these soils is appreciably above the optimum moisture content, these soils become muddy and unstable. During wet weather, operation of equipment on these soils will be difficult, and it will be difficult to meet the required compaction criteria. The wet weather season generally begins in early November and continues through March in Western Washington; however, periods of wet weather may occur during any month of the year. The optimum earthwork period for these types of soils is typically July through October. If wet weather earthwork is unavoidable, we recommend that: ■ Structural fill placed during the wet season or during periods of wet weather consist of gravel borrow conforming to PSE Base Course Aggregate Specification 1275.1310. ■ The ground surface in and around the work area be sloped so that surface water is directed away from the work area. The ground surface should be graded such that areas of ponded water do not develop. Measures should be taken by the contractor to prevent surface water from collecting in excavations and trenches. Measures should be implemented to remove surface water from the work area. Temporary Slopes The soils encountered at the site are classified as Type C soil, in accordance with the provisions of Title 296 WAC (Washington Administrative Code), Part N, “Excavation, Trenching and Shoring.” We recommend that temporary slopes in excess of 4 feet in height excavated in the on-site soils be inclined no steeper than 1½H:1V. Flatter slopes may be necessary if localized sloughing occurs. For open cuts at the site we recommend that: February 1, 2017 | Page 10 File No. 0186-953-00 ■ No traffic, construction equipment, stockpiles or building supplies be allowed at the top of the cut slopes within a horizontal distance of at least 5 feet from the top of the cut. ■ Exposed soil along the slope be protected from surface erosion using waterproof tarps or plastic sheeting. ■ Construction activities be scheduled so that the length of time the temporary cut is left open is kept as short as possible. ■ Erosion control measures be implemented as appropriate such that runoff from the site is reduced to the extent practical. ■ Surface water is diverted away from the excavation. ■ The general condition of the slopes be observed periodically by a geotechnical engineer to confirm adequate stability. Since the contractor has control of the construction operations, the contractor should be made responsible for the stability of cut slopes, as well as the safety of the excavations. All shoring and temporary slopes must conform to applicable local, state and federal safety regulations. LIMITATIONS We have prepared this report for the exclusive use of Puget Sound Energy and their authorized agents for the proposed Talbot Substation Improvements in Renton, Washington. Within the limitations of scope, schedule and budget, our services have been executed in accordance with generally accepted practices in the field of geotechnical engineering in this area at the time this report was prepared. No warranty or other conditions, express or implied, should be understood. Please refer to Appendix B, Report Limitations and Guidelines for Use, for additional information pertaining to use of this report. REFERENCES D. B. Booth, K. A. Troost, and A. P. Wisher, 2007, “Geologic Map of King County, Washington,” GeoMapNW, scale 1:100,000. D. R. Mullineaux, 1965, “Geologic map of the Renton quadrangle, King County, Washington,” U.S. Geological Survey, Open-File Report M200gq, scale 1:24,000. The National Geologic Map Database (NGMDB) portal accessed via: http://ngmdb.usgs.gov/ maps/mapview/ on October 3, 2014. U.S. Geological Survey Seismic Design Maps, accessed via: http://geohazards.usgs.gov/ designmaps/us/application.php on October 3, 2014. Washington Administrative Code Safety Standards for Construction Work information portal accessed via: http://app.leg.wa.gov/wac/default.aspx?cite=296-155 on October 3, 2014. MaplewoodGolf Course SSeeaattttlleeSSeeaattttlleeEEaassttRento nRenton CMSP and P Railroad ST167 ST167 I-405NWA-167 SWA-167NAberdeenCt SE126thPl SESE 19thCtS E 1 7 1 s tP l123rdPlSES 2 6 th P lLoga nAveS LynnwoodAveSEJonesPlSE S 33rd PlWhitworthCt SSE 166th Pl 114t hLn SEIndexCtSE S 10th StS 5th Pl 110thP lSENewportAve SES22nd Pl SE21s tCtL y n n w o o d Ct S E SE171 s tS tMain Ave SSE 5th Pl S 20thPl 115thAveSES 32nd Pl S 4 thPl HardieAveS WS 35t h StSmit h e r sAveSS 2 2n dCt 1 3 5 th A v e SE SE 159th St SE 166th St S 17thSt 119th St SE 128thPlSEShe lt onAv e SESE 29thSt 12 9t hPl SE131st A ve S ESE 173rd St S 18thSt SE18thPl UnionAve NESE4t hPl S 21stSt 133rdPlSES3r d Pl EagleLnS S E 3rdSt 117thAve SES 31s tSt Kir k landA v eSES E 2ndCt 109thAve SESE157thPlBurnet tPlS SE 16thPl SE149thSt S 3 6th St S 27th St S 9th St SE 22ndPl SE 2ndPl SE 21s tSt MonroeAveSEThom asLn SE 167t hSt NE 1stPl BurnettAveS N 2nd St HighAve SWhitw or t hAve SS E 169thSt SE 163rdSt SE 3 rd P l131stPlSEWA-167 SSE1st Pl Edmon dsWayS E127thAveSE13 0thAve SEFir DrSE 170thSt NE1stSt S RentonVillagePl 119thAveSERhodyD r CedarAveSS23r d St MontereyDr NE SE19thSt S E 8 th D rSE 162nd St S 2nd St SE7thSt HarringtonPlSES 19th St 123rdAve SEHouserWayNS 6th St MillAveSTalbotCrestDrS SE 161st St H ou serW aySSE 1 59thPlDavi sAve SSpruceDr SE6thS tBlaineAveNE104thAveSELakeAveS 1 2 0 t hT e r SESE1 6t h St111thAve SEBronsonWayNRosewood DrSE Maple ValleyHwy N 1st St Laurel DrFerndaleAveS E S 32ndS tS E 4th S tCedarRiverParkDr WA-515 S 7th St Jones Ave SS36t h P lCedarRidge DrSE SE151st S tSE170thPl AirportWayS S 5th St 12 1stAv eSE105th Ave SES 1 4 t h S t EdmondsAveSEUnion Ave SE113thAve SE128thAve SES Tobin St S 15th St NE 2nd St SE158thSt NE3rd S t Pier ceAve SE Morris AveS 106th Ave SESGrad y W aySE8thP l S4th St IndexAve SE SE160th St SE 5th St 120thAveSESE16 5th St SE 172nd St125th Ave SE132ndPlSEGrantAveS1 2 6thA v eSEWellsAveSS 3rd St RoyalHills DrS E P u get DrS ERainierAveSWilliamsAveSRentonAveSBeacon WayS Be nsonDrSSPuget Dr SE164th St 116thAve SESE 168th StTalbotR dS Maple ValleyHwy Be n s o nRd Sµ Vicinity Map Figure 1 PSE Talbot Substation ImprovementsRenton, Washington BellevueBellevueSeattleSeattle ¨§¦5 ¨§¦405 ¨§¦90 UV99 UV18 UV509 UV520 UV3 UV167UV16 2,000 2,0000 Feet Data Sources: ESRI Data & Maps, Street Maps 2005 Notes:1. The locations of all features shown are approximate.2. This drawing is for information purposes. It is intended to assist in showing features discussed in an attached document. GeoEngineers, Inc. cannot guarantee the accuracy and content of electronic files. The master file is stored by GeoEngineers, Inc. and will serve as the official record of this communication.3. It is unlawful to copy or reproduce all or any part thereof, whether for personal use or resale, without permission. Transverse Mercator, Zone 10 N North, North American Datum 1983North arrow oriented to grid northOffice: RedmondPath: \\red\projects\0\0186953\GIS\018695300_F1_VicinityMap.mxdMap Revised: 10/3/2014 ELSite 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 56789101112131415Bearing Capacity (ksf)Footing Width (ft) Spread Footing Capacity (chart based on 5' long footing supported on structural fill/glacially consolidated soil) Unfactored Bearing Capacity Extreme Event Capacity Resistance Factor (0.9) bearing resistance for seismic loading (Section 8.10; 2010 WSDOT GDM) Strength Limit State Service Limit State; 1-inch settlement Spread Footing Capacity Figure 30186‐953‐00   Exported 2/1/17PSE Talbot Substation Imrpovements Renton, Washington APPENDIX A Field Explorations and Laboratory Testing February 1, 2017 | Page A-1 File No. 0186-953-00 APPENDIX A FIELD EXPLORATIONS AND LABORATORY TESTING Field Explorations Subsurface conditions were explored at the site by completing seven borings (GEI-1 through GEI-7). The borings were completed by Geologic Drill Exploration, Inc. of Spokane, Washington, on September 25 and 26, 2014. The locations of the explorations were estimated in the field by measuring distances from site features through taping and pacing. The approximate exploration locations are shown on the Site Plan, Figure 2. Borings The drilling contractor hand dug to a depth of 2 feet at each boring location to be clear of the grounding grid before drilling. The borings were drilled using a tracked Bobcat-mounted hollow-stem auger drill rig. The borings were continuously observed by a geotechnical engineer from our firm who examined and classified the soils encountered, obtained representative soil samples, observed groundwater conditions and prepared a detailed log of each boring. Soils encountered in the borings were visually classified in general accordance with the classification system described in Figure A-1. A key to the exploration log symbols is also presented in Figure A-1. The logs of the borings are presented in Figures A-2 through A-8. The logs reflect our interpretation of the field conditions and the results of laboratory testing and evaluation of samples. They also indicate the depths at which the soil types or their characteristics change, although the change might actually be gradual. The borings were backfilled in accordance with Washington State Department of Ecology standards. The top 6 inches of yard rock was replaced over the completed boring to match existing yard rock. Groundwater Conditions Observations of groundwater conditions were made during drilling and are noted on the exploration logs; these observations represent a short-term condition that may not be representative of the long-term groundwater conditions at the site. Groundwater conditions observed during drilling should be considered approximate. Laboratory Testing Soil samples obtained from the field explorations were transported to our laboratory and examined to confirm or modify field classifications, as well as to evaluate index properties of the soil samples. Representative samples were selected for laboratory testing consisting of the determination of the percent fines (material passing the U.S. No. 200 sieve), moisture content and grain size distribution (sieve analysis). The tests were performed in general accordance with test methods of the ASTM International (ASTM) or other applicable procedures. Percent Passing U.S. No. 200 Sieve Selected samples were “washed” through the U.S. No. 200 mesh sieve to determine the relative percentages of coarse and fine-grained particles in the soil. The percent passing value represents the percentage by weight of the sample finer than the U.S. No. 200 sieve. These tests were conducted to verify February 1, 2017 | Page A-2 File No. 0186-953-00 field descriptions and to determine the fines content for analysis purposes. The tests were conducted in general accordance with ASTM D 1140, and the results are shown on the exploration logs at the respective sample depths. Moisture Content Testing Moisture content tests were completed using ASTM D 2216 for representative samples obtained from the explorations. The results of these tests are presented on the exploration logs at the depths where the samples were obtained. Sieve Analyses Sieve analyses were performed on selected samples in general accordance with ASTM D 422 to determine the sample grain size distribution. The wet sieve analysis method was used to determine the percentage of soil greater than the U.S. No. 200 mesh sieve. The results of the sieve analyses were plotted, were classified in general accordance with the Unified Soil Classification System (USCS), and are presented in Figures A-9 and A-10. Sheen Classification NOTE: The reader must refer to the discussion in the report text and the logs of explorations for a proper understanding of subsurface conditions. Descriptions on the logs apply only at the specific exploration locations and at the time the explorations were made; they arenot warranted to be representative of subsurface conditions at other locations or times. CC Asphalt Concrete NSSS MSHSNT Shelby tube ADDITIONAL MATERIAL SYMBOLS %FALCA CPCS DSHAMC MDOCPM PIPPPPM SATXUC VS Graphic Log Contact Distinct contact between soil strata orgeologic units Approximate location of soil strata change within a geologic soil unit Approximate location of soil stratachange within a geologic soil unit Measured groundwater level in exploration, well, or piezometer Measured free product in well orpiezometer GRAPH Topsoil/ Forest Duff/Sod Direct-Push Crushed Rock/Quarry Spalls Blowcount is recorded for driven samplers as the number of blows required to advance sampler 12 inches (ordistance noted). See exploration log for hammer weightand drop. A "P" indicates sampler pushed using the weight of thedrill rig. FIGURE A-1 2.4-inch I.D. split barrel SYMBOLS TYPICAL KEY TO EXPLORATION LOGS CR Bulk or grab Piston Standard Penetration Test (SPT) DESCRIPTIONSLETTER Distinct contact between soil strata orgeologic units TS GC PT OH CH MH OL GM GP GW DESCRIPTIONS TYPICAL LETTER (APPRECIABLE AMOUNT OF FINES) MAJOR DIVISIONS POORLY-GRADED SANDS,GRAVELLY SAND PEAT, HUMUS, SWAMP SOILSWITH HIGH ORGANICCONTENTS CLEAN SANDS GRAVELS WITH FINES CLEAN GRAVELS HIGHLY ORGANIC SOILS SILTS AND CLAYS SILTS AND CLAYS SANDANDSANDY SOILS GRAVEL AND GRAVELLY SOILS (LITTLE OR NO FINES) FINEGRAINED SOILS COARSE GRAINED SOILS SW MORE THAN 50%OF COARSEFRACTIONRETAINED ON NO.4 SIEVE CL WELL-GRADED SANDS,GRAVELLY SANDS SILTY GRAVELS, GRAVEL - SAND- SILT MIXTURES LIQUID LIMITGREATER THAN 50 SILTY SANDS, SAND - SILTMIXTURES (APPRECIABLE AMOUNTOF FINES) SOIL CLASSIFICATION CHART LIQUID LIMITLESS THAN 50 SANDS WITHFINES SP(LITTLE OR NO FINES) ML SC SM NOTE: Multiple symbols are used to indicate borderline or dual soil classifications MORE THAN 50%OF COARSEFRACTIONPASSING NO. 4SIEVE CLAYEY GRAVELS, GRAVEL -SAND - CLAY MIXTURES CLAYEY SANDS, SAND - CLAYMIXTURES INORGANIC SILTS, ROCKFLOUR, CLAYEY SILTS WITHSLIGHT PLASTICITY ORGANIC SILTS AND ORGANICSILTY CLAYS OF LOWPLASTICITY INORGANIC SILTS, MICACEOUSOR DIATOMACEOUS SILTYSOILS ORGANIC CLAYS AND SILTS OFMEDIUM TO HIGH PLASTICITY INORGANIC CLAYS OF HIGHPLASTICITY MORE THAN 50%PASSING NO. 200SIEVE MORE THAN 50%RETAINED ON NO.200 SIEVE WELL-GRADED GRAVELS,GRAVEL - SAND MIXTURES POORLY-GRADED GRAVELS,GRAVEL - SAND MIXTURES INORGANIC CLAYS OF LOW TOMEDIUM PLASTICITY, GRAVELLYCLAYS, SANDY CLAYS, SILTYCLAYS, LEAN CLAYS GRAPH SYMBOLS AC Cement Concrete Sampler Symbol Descriptions Groundwater Contact Material Description Contact No Visible SheenSlight Sheen Moderate SheenHeavy SheenNot Tested Laboratory / Field Tests Percent finesAtterberg limits Chemical analysisLaboratory compaction testConsolidation test Direct shearHydrometer analysisMoisture content Moisture content and dry densityOrganic contentPermeability or hydraulic conductivityPlasticity indexPocket penetrometer Parts per millionSieve analysisTriaxial compression Unconfined compressionVane shear 1 2 3SA 4 5 6%F 18 16 18 18 12 18 34 46 58 57 53 49 3/4-inch angular gravel Light brown silty fine to coarse sand with gravel(loose, moist) (fill) Brown fine to medium sand with silt, organicsand occasional gravel (loose, moist) (fill) Brown silty fine to medium sand withoccasional organics (dense, moist) (glacialtill) Light gray brown fine to medium sand with silt(dense, moist) Brown silty fine to medium sand withoccasional gravel (dense, moist) Gray brown silty fine to medium sand withoccasional gravel (very dense, moist) Gray brown silty fine to medium sand withoccasional gravel (very dense, moist) Becomes dense GP SM SP-SM SM SP-SM SM SM SM Excavated to 2 feet using hand tools Rough drilling 27 15 8 10 TotalDepth (ft) HammerData SystemDatum Start End Checked By Logged By CEWDrilled Notes: DML Surface Elevation (ft) Vertical Datum Driller Groundwater Depth toWater (ft)Date Measured Elevation (ft) Easting (X)Northing (Y) Mini Track Rig Geologic Drill DrillingMethod Hollow-stem Auger31.5 Rope & Cathead140 (lbs) / 30 (in) Drop DrillingEquipment 9/25/20149/25/2014 None Observed 438 Note: See Figure A-1 for explanation of symbols. FIELD DATA Depth (feet)0 5 10 15 20 IntervalElevation (feet)435430425420Sample NameTestingRecovered (in)Graphic LogCollected SampleBlows/footMATERIAL DESCRIPTION GroupClassificationWater LevelLog of Boring GEI-1 PSE Talbot Substation Improvements Renton, Washington 0186-953-00 Project: Project Location: Project Number:Figure A-2 Sheet 1 of 2Seattle: Date:11/2/14 Path:C:\USERS\KJANCI\DESKTOP\018695300.GPJ DBTemplate/LibTemplate:GEOENGINEERS8.GDT/GEI8_GEOTECH_STANDARDREMARKS FinesContent (%)MoistureContent (%) 7 8%F 18 18 58 52 Brown fine to medium sand with silt (verydense, moist) (advance outwash) SP-SM 1110 Note: See Figure A-1 for explanation of symbols. FIELD DATA Depth (feet)25 30 IntervalElevation (feet)415410Sample NameTestingRecovered (in)Graphic LogCollected SampleBlows/footMATERIAL DESCRIPTION GroupClassificationWater LevelLog of Boring GEI-1 (continued) PSE Talbot Substation Improvements Renton, Washington 0186-953-00 Project: Project Location: Project Number:Figure A-2 Sheet 2 of 2Seattle: Date:11/2/14 Path:C:\USERS\KJANCI\DESKTOP\018695300.GPJ DBTemplate/LibTemplate:GEOENGINEERS8.GDT/GEI8_GEOTECH_STANDARDREMARKS FinesContent (%)MoistureContent (%) 1 2SA 3%F 4 5 17 18 18 12 18 80 76 52 90/12" 53 3/4-inch angular gravel Light brown silty fine to coarse sand with gravel(loose, moist) (fill) Brown silty fine to medium sand withoccasional gravel (very dense, moist)(glacial till) Brown silty fine to medium sand with gravel(very dense, moist) Brown silty fine to medium sand (very dense,moist) (advance outwash) Brown fine to medium sand with silt andoccasional gravel (very dense, moist) Brown fine to medium sand with silt (verydense, moist) GP SM SM SM SM SP-SM SP-SM Excavated to 2 feet using hand tools 28 18 6 11 TotalDepth (ft) HammerData SystemDatum Start End Checked By Logged By CEWDrilled Notes: DML Surface Elevation (ft) Vertical Datum Driller Groundwater Depth toWater (ft)Date Measured Elevation (ft) Easting (X)Northing (Y) Mini Track Rig Geologic Drill DrillingMethod Hollow-stem Auger31.5 Rope & Cathead140 (lbs) / 30 (in) Drop DrillingEquipment 9/25/20149/25/2014 None Observed 438 Note: See Figure A-1 for explanation of symbols. FIELD DATA Depth (feet)0 5 10 15 20 IntervalElevation (feet)435430425420Sample NameTestingRecovered (in)Graphic LogCollected SampleBlows/footMATERIAL DESCRIPTION GroupClassificationWater LevelLog of Boring GEI-2 PSE Talbot Substation Improvements Renton, Washington 0186-953-00 Project: Project Location: Project Number:Figure A-3 Sheet 1 of 2Seattle: Date:11/2/14 Path:C:\USERS\KJANCI\DESKTOP\018695300.GPJ DBTemplate/LibTemplate:GEOENGINEERS8.GDT/GEI8_GEOTECH_STANDARDREMARKS FinesContent (%)MoistureContent (%) 6 7%F 18 18 39 12 Becomes light brown and dense Brown fine to medium sand (medium dense,moist) SP 57 Note: See Figure A-1 for explanation of symbols. FIELD DATA Depth (feet)25 30 IntervalElevation (feet)415410Sample NameTestingRecovered (in)Graphic LogCollected SampleBlows/footMATERIAL DESCRIPTION GroupClassificationWater LevelLog of Boring GEI-2 (continued) PSE Talbot Substation Improvements Renton, Washington 0186-953-00 Project: Project Location: Project Number:Figure A-3 Sheet 2 of 2Seattle: Date:11/2/14 Path:C:\USERS\KJANCI\DESKTOP\018695300.GPJ DBTemplate/LibTemplate:GEOENGINEERS8.GDT/GEI8_GEOTECH_STANDARDREMARKS FinesContent (%)MoistureContent (%) 1MC 2SA 3%F 4 5 6 18 18 18 16 18 18 14 28 31 50 52 25 3/4-inch gravel Light brown silty fine to coarse sand with gravel(loose, moist) (fill) Gray brown with oxidation staining silty fine tomedium sand with occasional gravel(medium dense, moist) (glacial till) Brown silty fine to medium sand (mediumdense, moist) Brown silty fine to medium sand with gravel(dense, moist) Brown fine to medium sand with silt andoccasional gravel (dense to very dense,moist) (advance outwash) Becomes medium dense GP SM SM SM SM SP-SM Excavated to 2 feet using hand tools 26 16 13 12 8 TotalDepth (ft) HammerData SystemDatum Start End Checked By Logged By CEWDrilled Notes: DML Surface Elevation (ft) Vertical Datum Driller Groundwater Depth toWater (ft)Date Measured Elevation (ft) Easting (X)Northing (Y) Mini Track Rig Geologic Drill DrillingMethod Hollow-stem Auger21.5 Rope & Cathead140 (lbs) / 30 (in) Drop DrillingEquipment 9/25/20149/25/2014 None Observed 438 Note: See Figure A-1 for explanation of symbols. FIELD DATA Depth (feet)0 5 10 15 20 IntervalElevation (feet)435430425420Sample NameTestingRecovered (in)Graphic LogCollected SampleBlows/footMATERIAL DESCRIPTION GroupClassificationWater LevelLog of Boring GEI-3 PSE Talbot Substation Improvements Renton, Washington 0186-953-00 Project: Project Location: Project Number:Figure A-4 Sheet 1 of 1Seattle: Date:11/2/14 Path:C:\USERS\KJANCI\DESKTOP\018695300.GPJ DBTemplate/LibTemplate:GEOENGINEERS8.GDT/GEI8_GEOTECH_STANDARDREMARKS FinesContent (%)MoistureContent (%) 1 2 3 4SA 5 6 7 17 18 18 18 16 18 18 9 6 29 36 40 34 59 3/4-inch gravel Light brown silty fine to coarse sand with gravel(loose, moist) (fill) Brown silty fine to medium sand withoccasional gravel (loose, moist) (fill) Lacks gravel, becomes light brown With oxidation staining Light brown fine to medium sand with silt andoccasional gravel (medium dense, moist)(advance outwash) Brown silty fine to medium sand withoccasional gravel (dense, moist) Gray brown fine to medium sand with silt(dense, moist) Gray brown fine to medium sand with silt andoccasional gravel (medium dense, moist) Becomes very dense GP SM SM SP-SM SM SP-SM SP-SM Excavated to 2 feet using hand tools 1913 TotalDepth (ft) HammerData SystemDatum Start End Checked By Logged By CEWDrilled Notes: DML Surface Elevation (ft) Vertical Datum Driller Groundwater Depth toWater (ft)Date Measured Elevation (ft) Easting (X)Northing (Y) Mini Track Rig Geologic Drill DrillingMethod Hollow-stem Auger31.5 Rope & Cathead140 (lbs) / 30 (in) Drop DrillingEquipment 9/25/20149/25/2014 None Observed 438 Note: See Figure A-1 for explanation of symbols. FIELD DATA Depth (feet)0 5 10 15 20 IntervalElevation (feet)435430425420Sample NameTestingRecovered (in)Graphic LogCollected SampleBlows/footMATERIAL DESCRIPTION GroupClassificationWater LevelLog of Boring GEI-4 PSE Talbot Substation Improvements Renton, Washington 0186-953-00 Project: Project Location: Project Number:Figure A-5 Sheet 1 of 2Seattle: Date:11/2/14 Path:C:\USERS\KJANCI\DESKTOP\018695300.GPJ DBTemplate/LibTemplate:GEOENGINEERS8.GDT/GEI8_GEOTECH_STANDARDREMARKS FinesContent (%)MoistureContent (%) 8MC 9 18 17 34 59 Lacks gravel, becomes dense With occasional gravel, becomes very dense 9 Note: See Figure A-1 for explanation of symbols. FIELD DATA Depth (feet)25 30 IntervalElevation (feet)415410Sample NameTestingRecovered (in)Graphic LogCollected SampleBlows/footMATERIAL DESCRIPTION GroupClassificationWater LevelLog of Boring GEI-4 (continued) PSE Talbot Substation Improvements Renton, Washington 0186-953-00 Project: Project Location: Project Number:Figure A-5 Sheet 2 of 2Seattle: Date:11/2/14 Path:C:\USERS\KJANCI\DESKTOP\018695300.GPJ DBTemplate/LibTemplate:GEOENGINEERS8.GDT/GEI8_GEOTECH_STANDARDREMARKS FinesContent (%)MoistureContent (%) 1A 1B 2 3SA 4 5MC 6 18 18 18 18 18 18 17 15 30 28 42 63 6 inches topsoil/root zone Brown silty fine to medium sand withoccasional gravel and trace organics (loose,moist) Brown with oxidation staining silty fine to medium sand (medium dense, moist) (fill) Gray silty fine to medium sand with occasionalgravel (medium dense, moist) (fill) Gray brown silty fine to medium sand withoccasional gravel (medium dense, moist)(glacial till) Gray brown silty fine to medium sand (mediumdense, moist) Light gray brown silty fine to medium sand withoccasional gravel (dense, moist) TS SM SM SM SM SM SM 158 14 TotalDepth (ft) HammerData SystemDatum Start End Checked By Logged By CEWDrilled Notes: DML Surface Elevation (ft) Vertical Datum Driller Groundwater Depth toWater (ft)Date Measured Elevation (ft) Easting (X)Northing (Y) Mini Track Rig Geologic Drill DrillingMethod Hollow-stem Auger31.5 Rope & Cathead140 (lbs) / 30 (in) Drop DrillingEquipment 9/26/20149/26/2014 None Observed 443 Note: See Figure A-1 for explanation of symbols. FIELD DATA Depth (feet)0 5 10 15 20 IntervalElevation (feet)440435430425Sample NameTestingRecovered (in)Graphic LogCollected SampleBlows/footMATERIAL DESCRIPTION GroupClassificationWater LevelLog of Boring GEI-5 PSE Talbot Substation Improvements Renton, Washington 0186-953-00 Project: Project Location: Project Number:Figure A-6 Sheet 1 of 2Seattle: Date:11/2/14 Path:C:\USERS\KJANCI\DESKTOP\018695300.GPJ DBTemplate/LibTemplate:GEOENGINEERS8.GDT/GEI8_GEOTECH_STANDARDREMARKS FinesContent (%)MoistureContent (%) 7%F 8 18 18 67 51 Gray brown fine to medium sand with silt andoccasional gravel (very dense, moist)(advance outwash) SP-SM 117 Note: See Figure A-1 for explanation of symbols. FIELD DATA Depth (feet)25 30 IntervalElevation (feet)420415Sample NameTestingRecovered (in)Graphic LogCollected SampleBlows/footMATERIAL DESCRIPTION GroupClassificationWater LevelLog of Boring GEI-5 (continued) PSE Talbot Substation Improvements Renton, Washington 0186-953-00 Project: Project Location: Project Number:Figure A-6 Sheet 2 of 2Seattle: Date:11/2/14 Path:C:\USERS\KJANCI\DESKTOP\018695300.GPJ DBTemplate/LibTemplate:GEOENGINEERS8.GDT/GEI8_GEOTECH_STANDARDREMARKS FinesContent (%)MoistureContent (%) 1 2 3MC 4 5 18 16 18 14 18 27 25 32 51 78 6 inches topsoil/root zone Brown silty fine to medium sand withoccasional gravel and trace organics (loose,moist) Brown with oxidation staining silty fine tomedium sand with occasional gravel andoccasional organics (medium dense, dry)(glacial till) Brown silty fine to medium sand withoccasional gravel (medium dense, moist) Brown fine to medium sand with silt and gravel(dense, moist) Gray brown silty fine medium sand withoccaional gravel (very dense, moist) Gray brown fine to medium sand with silt andoccasional gravel (very dense, moist)(advance outwash) TS SM SM SM SP-SM SM SP-SM 7 TotalDepth (ft) HammerData SystemDatum Start End Checked By Logged By CEWDrilled Notes: DML Surface Elevation (ft) Vertical Datum Driller Groundwater Depth toWater (ft)Date Measured Elevation (ft) Easting (X)Northing (Y) Mini Track Rig Geologic Drill DrillingMethod Hollow-stem Auger16.5 Rope & Cathead140 (lbs) / 30 (in) Drop DrillingEquipment 9/26/20149/26/2014 None Observed 440 Note: See Figure A-1 for explanation of symbols. FIELD DATA Depth (feet)0 5 10 15 IntervalElevation (feet)435430425Sample NameTestingRecovered (in)Graphic LogCollected SampleBlows/footMATERIAL DESCRIPTION GroupClassificationWater LevelLog of Boring GEI-6 PSE Talbot Substation Improvements Renton, Washington 0186-953-00 Project: Project Location: Project Number:Figure A-7 Sheet 1 of 1Seattle: Date:11/2/14 Path:C:\USERS\KJANCI\DESKTOP\018695300.GPJ DBTemplate/LibTemplate:GEOENGINEERS8.GDT/GEI8_GEOTECH_STANDARDREMARKS FinesContent (%)MoistureContent (%) 1 2%F 3 4 13 18 18 18 13 43 28 46 6 inches topsoil/root zone Brown silty fine to medium sand withoccasional gravel and trace organics (loose,moist) Light brown silty fine to medium sand withoccasional gravel (medium dense, dry) (fill) Light brown silty fine to medium sand withgravel (medium dense, dry to moist) (glacial till) Brown fine to medium sand with silt andoccasional gravel (medium dense, moist)(advance outwash) Brown fine to medium sand with silt (dense,moist) TS SM SM SM SP-SM SP-SM 155 TotalDepth (ft) HammerData SystemDatum Start End Checked By Logged By CEWDrilled Notes: DML Surface Elevation (ft) Vertical Datum Driller Groundwater Depth toWater (ft)Date Measured Elevation (ft) Easting (X)Northing (Y) Mini Track Rig Geologic Drill DrillingMethod Hollow-stem Auger16.5 Rope & Cathead140 (lbs) / 30 (in) Drop DrillingEquipment 9/26/20149/26/2014 None Observed 443 Note: See Figure A-1 for explanation of symbols. FIELD DATA Depth (feet)0 5 10 15 IntervalElevation (feet)440435430Sample NameTestingRecovered (in)Graphic LogCollected SampleBlows/footMATERIAL DESCRIPTION GroupClassificationWater LevelLog of Boring GEI-7 PSE Talbot Substation Improvements Renton, Washington 0186-953-00 Project: Project Location: Project Number:Figure A-8 Sheet 1 of 1Seattle: Date:11/2/14 Path:C:\USERS\KJANCI\DESKTOP\018695300.GPJ DBTemplate/LibTemplate:GEOENGINEERS8.GDT/GEI8_GEOTECH_STANDARDREMARKS FinesContent (%)MoistureContent (%) FIGURE A-9 SIEVE ANALYSIS RESULTSEXPLORATION NUMBERDEPTH(ft)SOIL CLASSIFICATIONGEI-1GEI-2GEI-3GEI-47½ 5510Silty fine to medium sand with gravel (SM)Silty fine to medium sand with gravel (SM)Silty fine to medium sand (SM)Silty fine to medium sand (SM)0186-953-00 SAS: SAS 10-10-2014SYMBOL3/8”3” #20 #200#40 #60 #1001.5” #10#43/4”01020304050607080901000.0010.010.11101001000PERCENT PASSING BY WEIGHT .GRAIN SIZE IN MILLIMETERSU.S. STANDARD SIEVE SIZESANDSILT OR CLAYCOBBLESGRAVELCOARSE MEDIUM FINECOARSE FINEBOULDERS FIGURE A-10 SIEVE ANALYSIS RESULTSEXPLORATION NUMBERDEPTH(ft)SOIL CLASSIFICATIONGEI-57½ Silty fine to medium sand (SM)0186-953-00 SAS: SAS 10-10-2014SYMBOL3/8”3” #20 #200#40 #60 #1001.5” #10#43/4”01020304050607080901000.0010.010.11101001000PERCENT PASSING BY WEIGHT .GRAIN SIZE IN MILLIMETERSU.S. STANDARD SIEVE SIZESANDSILT OR CLAYCOBBLESGRAVELCOARSE MEDIUM FINECOARSE FINEBOULDERS APPENDIX B Report Limitations and Guidelines for Use February 1, 2017 | Page B-1 File No. 0186-953-00 APPENDIX B REPORT LIMITATIONS AND GUIDELINES FOR USE1 This appendix provides information to help you manage your risks with respect to the use of this report. Geotechnical Services Are Performed for Specific Purposes, Persons and Projects This report has been prepared for the exclusive use of Puget Sound Energy and their authorized agents. This report may be made available to prospective contractors for their bidding or estimating purposes, but our report, conclusions and interpretations should not be construed as a warranty of the subsurface conditions. This report is not intended for use by others, and the information contained herein is not applicable to other sites. GeoEngineers structures our services to meet the specific needs of our clients. For example, a geotechnical or geologic study conducted for a civil engineer or architect may not fulfill the needs of a construction contractor or even another civil engineer or architect that are involved in the same project. Because each geotechnical or geologic study is unique, each geotechnical engineering or geologic report is unique, prepared solely for the specific client and project site. Our report is prepared for the exclusive use of our Client. No other party may rely on the product of our services unless we agree in advance to such reliance in writing. This is to provide our firm with reasonable protection against open-ended liability claims by third parties with which there would otherwise be no contractual limits to their actions. Within the limitations of scope, schedule and budget, our services have been executed in accordance with our Agreement with the Client and generally accepted geotechnical practices in this area at the time this report was prepared. This report should not be applied for any purpose or project except the one originally contemplated. A Geotechnical Engineering or Geologic Report Is Based on a Unique Set of Project-Specific Factors This report has been prepared for the proposed improvements to the Talbot Substation located in Renton, Washington. GeoEngineers considered a number of unique, project-specific factors when establishing the scope of services for this project and report. Unless GeoEngineers specifically indicates otherwise, do not rely on this report if it was: ■ not prepared for you, ■ not prepared for your project, ■ not prepared for the specific site explored, or ■ completed before important project changes were made.                                                                1 Developed based on material provided by ASFE, Professional Firms Practicing in the Geosciences; www.asfe.org. February 1, 2017 | Page B-2 File No. 0186-953-00 For example, changes that can affect the applicability of this report include those that affect: ■ the function of the proposed structure; ■ elevation, configuration, location, orientation or weight of the proposed structure; ■ composition of the design team; or ■ project ownership. If important changes are made after the date of this report, GeoEngineers should be given the opportunity to review our interpretations and recommendations and provide written modifications or confirmation, as appropriate. Subsurface Conditions Can Change This geotechnical or geologic report is based on conditions that existed at the time the study was performed. The findings and conclusions of this report may be affected by the passage of time, by manmade events such as construction on or adjacent to the site, or by natural events such as floods, earthquakes, slope instability or groundwater fluctuations. Always contact GeoEngineers before applying a report to determine if it remains applicable. Most Geotechnical and Geologic Findings Are Professional Opinions Our interpretations of subsurface conditions are based on field observations from widely spaced sampling locations at the site. Site exploration identifies subsurface conditions only at those points where subsurface tests are conducted or samples are taken. GeoEngineers reviewed field and laboratory data and then applied our professional judgment to render an opinion about subsurface conditions throughout the site. Actual subsurface conditions may differ, sometimes significantly, from those indicated in this report. Our report, conclusions and interpretations should not be construed as a warranty of the subsurface conditions. Geotechnical Engineering Report Recommendations Are Not Final Do not over-rely on the preliminary construction recommendations included in this report. These recommendations are not final, because they were developed principally from GeoEngineers’ professional judgment and opinion. GeoEngineers’ recommendations can be finalized only by observing actual subsurface conditions revealed during construction. GeoEngineers cannot assume responsibility or liability for this report's recommendations if we do not perform construction observation. Sufficient monitoring, testing and consultation by GeoEngineers should be provided during construction to confirm that the conditions encountered are consistent with those indicated by the explorations, to provide recommendations for design changes should the conditions revealed during the work differ from those anticipated, and to evaluate whether or not earthwork activities are completed in accordance with our recommendations. Retaining GeoEngineers for construction observation for this project is the most effective method of managing the risks associated with unanticipated conditions.   February 1, 2017 | Page B-3 File No. 0186-953-00 A Geotechnical Engineering or Geologic Report Could Be Subject to Misinterpretation Misinterpretation of this report by other design team members can result in costly problems. You could lower that risk by having GeoEngineers confer with appropriate members of the design team after submitting the report. Also retain GeoEngineers to review pertinent elements of the design team's plans and specifications. Contractors can also misinterpret a geotechnical engineering or geologic report. Reduce that risk by having GeoEngineers participate in pre-bid and preconstruction conferences, and by providing construction observation. Do Not Redraw the Exploration Logs Geotechnical engineers and geologists prepare final boring and testing logs based upon their interpretation of field logs and laboratory data. To prevent errors or omissions, the logs included in a geotechnical engineering or geologic report should never be redrawn for inclusion in architectural or other design drawings. Only photographic or electronic reproduction is acceptable, but recognize that separating logs from the report can elevate risk. Give Contractors a Complete Report and Guidance Some owners and design professionals believe they can make contractors liable for unanticipated subsurface conditions by limiting what they provide for bid preparation. To help prevent costly problems, give contractors the complete geotechnical engineering or geologic report, but preface it with a clearly written letter of transmittal. In that letter, advise contractors that the report was not prepared for purposes of bid development and that the report's accuracy is limited; encourage them to confer with GeoEngineers and/or to conduct additional study to obtain the specific types of information they need or prefer. A pre-bid conference can also be valuable. Be sure contractors have sufficient time to perform additional study. Only then might an owner be in a position to give contractors the best information available, while requiring them to at least share the financial responsibilities stemming from unanticipated conditions. Further, a contingency for unanticipated conditions should be included in your project budget and schedule. Contractors Are Responsible for Site Safety on Their Own Construction Projects Our geotechnical recommendations are not intended to direct the contractor’s procedures, methods, schedule or management of the work site. The contractor is solely responsible for job site safety and for managing construction operations to minimize risks to on-site personnel and to adjacent properties. Read These Provisions Closely Some clients, design professionals and contractors may not recognize that the geoscience practices (geotechnical engineering or geology) are far less exact than other engineering and natural science disciplines. This lack of understanding can create unrealistic expectations that could lead to disappointments, claims and disputes. GeoEngineers includes these explanatory “limitations” provisions in our reports to help reduce such risks. Please confer with GeoEngineers if you are unclear how these “Report Limitations and Guidelines for Use” apply to your project or site. Geotechnical, Geologic and Environmental Reports Should Not Be Interchanged The equipment, techniques and personnel used to perform an environmental study differ significantly from those used to perform a geotechnical or geologic study and vice versa. For that reason, a geotechnical engineering or geologic report does not usually relate any environmental findings, conclusions or February 1, 2017 | Page B-4 File No. 0186-953-00 recommendations; e.g., about the likelihood of encountering underground storage tanks or regulated contaminants. Similarly, environmental reports are not used to address geotechnical or geologic concerns regarding a specific project. Biological Pollutants GeoEngineers’ Scope of Work specifically excludes the investigation, detection, prevention or assessment of the presence of Biological Pollutants. Accordingly, this report does not include any interpretations, recommendations, findings, or conclusions regarding the detecting, assessing, preventing or abating of Biological Pollutants and no conclusions or inferences should be drawn regarding Biological Pollutants, as they may relate to this project. The term “Biological Pollutants” includes, but is not limited to, molds, fungi, spores, bacteria, and viruses, and/or any of their byproducts. If Client desires these specialized services, they should be obtained from a consultant who offers services in this specialized field.