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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.
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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
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P u get
DrS ERainierAveSWilliamsAveSRentonAveSBeacon
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Be
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SE164th St
116thAve SESE 168th StTalbotR
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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.
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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
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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.