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I-405 corridor
South Renton Transit Center
Geotechnical Recommendation
Report
March 2022
FOR REFERENCE ONLY. Proposed
Temporary Use Permit (TUP) scope of
work is limited to soil remediation and
temporary artwork only. All other
improvements referenced in this report
are not proposed as part of the TUP
application.
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Page i | AE 0054-17 | South Renton Transit Center Geotechnical Recommendation Report March 2022
Consultant Quality Control Form
Version Title Date
Originator/
Drafted by Reviewed by
Approved
by
Notes, as
required
0 South Renton
Transit Center
Geotechnical
Recommendation
Report – Draft
11/22/2021 Matteo
Montesi
(WSP)
Elizabeth
Lundquist
(WSP)
Ed Reynolds
(tech edit)
Sandra Wise
(QA/QC)
Rob Gorman
(WSP)
For ST review
1 South Renton
Transit Center
Geotechnical
Recommendation
Report
3/21/2022 Michelle Cline
(WSP)
Elizabeth
Lundquist
(WSP)
Ed Reynolds
(tech edit)
Rob Gorman
(WSP)
Addressed ST
comments
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Page ii | AE 0054-17 | South Renton Transit Center Geotechnical Recommendation Report March 2022
Summary
Purpose
This Geotechnical Recommendation Report (GRR) documents procedures and presents the
findings of the preliminary geotechnical investigation conducted for the proposed improvements
at the South Renton Transit Center (SRTC) for the Sound Transit I-405 Bus Rapid Transit (BRT)
project.
The additional borings performed for this phase of work encountered similar subsurface
conditions to those reported during prior phases of this project across much of the site. In
addition, boring SB-2 encountered bedrock at about 75 feet below ground surface. The
subsurface investigation program is deemed sufficient for the features covered in this report.
Nevertheless, additional subsurface investigations may be required to support the design of the
proposed parking structure (not covered in this report).
The subsurface conditions are generally characterized by a surficial layer of fills over alluvial
deposits. The alluvial deposits are generally very loose and loose in the upper portion while they
become denser at depth. Interbedded layers of peats and highly organic soils were encountered
in most borings.
WSP concurs with HWA’s previous assessment that liquefaction poses a significant hazard at
the site. Up to 40 feet of potentially liquefiable soils may be present at the site, which may
experience up to 2 feet of liquefaction-induced settlement. Ground improvement mitigation
measures and deep foundations are likely cost prohibitive for small structures.
The proposed bus shelters are recommended to be supported on slabs-on-grade with a
maximum allowable bearing pressure of 1,000 psf. The bearing pressure is limited due to the
presence of very loose and loose alluvial deposits as well as compressible peats and highly
organics soils.
Flexible pavement will be used in the parking garage access areas and interim parking lot. Rigid
pavement will be used for the bus lanes and layover area. A discussion of pavement design,
including recommended thickness, is presented in this report. Due to soft subgrade conditions
and shallow groundwater, it is recommended to place geosynthetics over properly prepared
subgrade prior to placing pavement materials.
This report has been prepared for the exclusive use of Sound Transit for the design and
construction of the bus shelter foundations, pavements, and retaining walls considered for the
SRTC site as part of the Sound Transit I-405 BRT project. The findings, conclusions, and
recommendations presented in this report are applicable only to the specific project study
elements and locations described and are not intended to apply to any other design elements or
locations. All subsequent users shall accept any and all liability resulting from any use or reuse
of the data, opinions, and recommendations without the prior written consent of WSP.
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Table of Contents
1 INTRODUCTION ......................................................................................................................... 1
1.1 Background ........................................................................................................... 1
1.2 Purpose and Scope of Work ................................................................................. 1
1.3 Site Description and Existing Facilities .................................................................. 3
1.4 Proposed Improvements ....................................................................................... 3
2 GEOTECHNICAL INVESTIGATION PROGRAM ..................................................................... 3
2.1 Existing Geotechnical Data ................................................................................... 3
2.2 Borehole Investigation ........................................................................................... 3
2.3 Geophysical Surveys ............................................................................................. 4
2.4 Laboratory Testing ................................................................................................ 4
3 SITE CONDITIONS ..................................................................................................................... 5
3.1 General Geologic Conditions ................................................................................ 5
3.2 Subsurface Conditions .......................................................................................... 5
3.3 Groundwater .......................................................................................................... 6
4 GEOTECHNICAL RECOMMENDATIONS ................................................................................ 6
4.1 Preliminary Seismic Design Parameters ............................................................... 6
4.2 Liquefaction and Seismic Settlement .................................................................... 7
4.3 Foundation Recommendations for Bus Shelters ................................................... 7
4.4 Recommendations for Earth Retaining Structures ................................................ 8
4.5 Pavement Design and Recommendations ............................................................ 8
4.6 Site Preparation and Grading .............................................................................. 10
4.7 Temporary Excavations ....................................................................................... 11
4.8 Structural Fill and Compaction ............................................................................ 11
4.9 Groundwater Control ........................................................................................... 11
5 REFERENCES .......................................................................................................................... 12
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Figures
Figure 1-1 I-405 Bus Rapid Transit Project ............................................................................ 2
Tables
Table 2-1 Design Seismic Coefficients per AASHTO ............................................................ 4
Table 4-1 Preliminary Seismic Design Coefficients ............................................................... 6
Table 4-2 Design ESALs (20-year Design Life) ..................................................................... 9
Table 4-3 Recommended Flexible Pavement Sections ......................................................... 9
Table 4-4 Recommended Rigid Pavement Section ............................................................... 9
Appendices
Appendix A Detailed Figures:
Appendix B Existing Geotechnical Information by Others
Appendix C Boring Logs
Appendix D Geophysical Survey Report
Appendix E Laboratory Test Results
Appendix F Pavement Design Data and Calculations
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Acronyms and Abbreviations
BRT bus rapid transit
GRR Geotechnical Recommendation Report
PE preliminary engineering
SRTC South Renton Transit Center
WSDOT Washington State Department of Transportation
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1 INTRODUCTION
1.1 Background
WSP USA (WSP) was retained by Sound Transit to provide engineering design services for the
I-405 Bus Rapid Transit (BRT) project located in Washington state. The I-405 BRT project
would provide BRT service along the I-405 corridor spanning 37 miles between the cities of
Lynwood and Burien. The proposed project alignment and stations are presented in Figure 1-1.
This project stage involves preliminary engineering (PE) design of BRT elements, including BRT
stations and park-and-ride facilities. The I-405 BRT project also includes two new parking
garages: one at the Totem Lake/Kingsgate Park-and-Ride site and one at the South Renton
Transit Center (SRTC) site. At this time, final design and construction of both parking garages
have been delayed. This report covers the SRTC site and the associated bus shelter and any
retaining structures that may be needed.
1.2 Purpose and Scope of Work
The purpose of this Geotechnical Recommendation Report (GRR) is to provide the required
geotechnical information and design recommendations in support of the proposed SRTC
improvements as part of the I-405 BRT project. This report provides preliminary geotechnical
design recommendations pertaining to bus shelters, retaining walls, seismic considerations, and
pavements.
WSP scope of work included the following:
Field investigation: Perform seven (7) borings between 32 and 105 feet deep with periodic
sampling (Section 2.2)
Geophysical Testing: Perform suspension hole logging in two borings (Section 2.3)
Laboratory testing: Perform geotechnical laboratory tests on selected soil samples (Section
2.4)
Geotechnical engineering analyses
Preparation of this report
The information provided in this report is based on the boring log and laboratory testing of the
recently drilled boring, existing geotechnical data, and published literature.
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Figure 1-1 I-405 Bus Rapid Transit Project
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1.3 Site Description and Existing Facilities
The SRTC site is located in the city of Renton, Washington, and is located between Rainier
Avenue S., S Grady Way, and Lake Avenue S. The site is generally level with the majority of the
site paved with an asphalt parking lot. Four existing building structures are present at the site at
the time of the subsurface investigation and are planned to be demolished before any project
elements are constructed. In the southern portion of the site (adjacent to S Grady Way), there is
an existing Puget Sound Energy power line easement. In the eastern portion of the site
(adjacent to Lake Avenue S) there is an existing Seattle City Light power line easement. Along
the south boundary, the easement is approximately 100 feet wide. In the eastern portion of the
site, the easement is approximately 200 feet wide. Prior to the start of construction, Sound
Transit will coordinate with Puget Sound Energy, Seattle City Light, and other utility providers as
needed to ensure construction activities would not interfere with their facilities and service.
There are a few trees on the site primarily confined to the borders of the site and landscaped
areas. The site is sparsely vegetated with small trees and landscaping at the edges of the site
bordering S Grady Way and Rainier Avenue S.
1.4 Proposed Improvements
The proposed improvements for the site may include a new parking garage, bus shelters, and
earth retaining structures. The new parking garage is not part of this report and is therefore not
discussed herein. When this report was prepared, the final locations and details of bus shelters
and earth retaining structures were unknown.
2 GEOTECHNICAL INVESTIGATION PROGRAM
2.1 Existing Geotechnical Data
During the project’s conceptual engineering phase, HWA completed a geotechnical
investigation for this project at the SRTC site and summarized their findings in a Geotechnical
Data Report dated 2020 (HWA, 2020). The HWA field investigation consisted of four (4) borings
to depths varying between 45 and 81.5 feet below ground surface. A monitoring well was
installed as part of the HWA investigation program, and laboratory tests on selected samples
were also performed. Relevant information from previous geotechnical investigations is
presented in Appendix B.
2.2 Borehole Investigation
A geotechnical investigation program was performed at the SRTC site in July and August 2021,
which included seven (7) borings advanced between 32 and 105 feet below the ground surface.
This field investigation supplements previous field investigations performed by HWA during an
earlier phase of the project. The results of HWA’s investigation are provided in the I-405 Bus
Rapid Transit Project – Parking Garages Geotechnical Data Report (HWA, 2020). The drilling
and sampling for the current investigations were performed by Holt Services, Inc. using a truck-
mounted CME 85 drill rig equipped with a 5-inch outer diameter drilling system. All boring
locations were cleared by requesting the One Call service as well as by utilizing a private
geophysical subcontractor. The borings were advanced using rotary wash drilling techniques.
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The approximate boring locations are presented in the Geotechnical Exploration Plan (Appendix
A, Figure A-4). A geotechnical engineer from WSP coordinated the field exploration activities
and was present full time to log the borehole and collect samples for further examination and
laboratory testing.
Soil samples were obtained using Standard Penetration Test (SPT, ASTM D1586) samplers at
2.5-foot intervals in the top 15 feet and at 5-foot depth intervals thereafter. Modified California
sampler (3.25-inch outer diameter) and Shelby tube samplers were also used to obtain relatively
undisturbed and undisturbed samples, respectively.
Borings were backfilled with a bentonite mix, except for borings SB-1 and SB-2 where
monitoring wells were installed. The excess soil cuttings were tested and disposed offsite by the
drilling subcontractor. Boring logs are presented in Appendix C.
2.3 Geophysical Surveys
Downhole geophysical surveys were conducted in borings SB-1 and SB-2. At both locations,
shear wave data were measured in the boring at 2.5-foot intervals, and compressional wave
data were measured at 5-foot intervals. Boring SB-1 near the northeast corner of the existing
building was completed at a depth of 105 feet and the deepest data point is at 103.75 feet.
Boring SB-2 is located near the southeast corner, completed at a depth of 70 feet with the
deepest data point at 68.75 feet. Presentation of the field methodology and results of the
geophysical surveys is provided in Appendix D.
2.4 Laboratory Testing
A laboratory test program was conducted to confirm field classifications and obtain additional
information on selected physical and mechanical properties of the materials encountered in the
boreholes. Geotechnical laboratory testing was performed by HWA Geosciences of Bothell,
Washington. Table 2-1 presents a summary of the laboratory tests that were performed. The
laboratory test results are provided in Appendix E.
Table 2-1 Design Seismic Coefficients per AASHTO
Laboratory Test Standard Quantity
Moisture Content ASTM D2216 25
Organic Content ASTM D2974 2
Unit Weight ASTM D2937 3
Passing #200 Sieve ASTM D1140 10
Particle Size Analysis ASTM D6913/D7928 4
Atterberg Limits ASTM D4318 10
Direct Shear ASTM D3080 1
Specific Gravity ASTM D854 2
One Dimensional Consolidation ASTM D2435 3
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3 SITE CONDITIONS
3.1 General Geologic Conditions
The site is mapped as Quaternary alluvial deposits (Qa) by Schuster (2015). Qa is generally
described as “loose, stratified to massively bedded fluvial silt, sand, and gravel: typically well
rounded and moderately to well sorted; locally includes sandy to silty estuarine deposits” and is
typically unconsolidated. This geologic unit was identified in the borings conducted by HWA and
WSP.
3.2 Subsurface Conditions
Based on the findings of the most recent subsurface investigation performed by WSP and the
previous investigation at the site performed by HWA, the subsurface soils at the SRTC site
generally consist of 5 to 10 feet of very loose to medium dense fill soils over alluvial deposits.
The alluvial deposits are mostly coarse grained, very loose to loose in the upper portion. They
become dense to very dense at a depth of approximately 20 to 45 feet below ground surface.
Hydrocarbon odors were observed in the fill soils. Organic materials (including peat deposits) up
to 20 feet were encountered in various borings. Bedrock was encountered in boring SB-2 at a
depth of approximately 75 feet below ground surface. A brief description of these strata
encountered in WSP borings is presented below.
The artificial fill is characterized by a thickness up to 10 feet and consists of very loose to
medium dense silty sands (SM) and poorly graded sands (SP). Uncorrected SPT N-values vary
between 2 and 24.
A layer of very loose to loose alluvium lies underneath the artificial fill. The thickness of this
layer varies between 5 and 25 feet and consists mainly of silty sands (SM) and poorly graded
sands (SP) and silts with varying plasticity (ML and MH). Uncorrected SPT N-values vary
between 0 and 9.
A layer of organics (PT, OH, OL) was encountered in borings RW-10, RW-11, RW-12, SB-1,
SH4 and SH-5. The thickness of this stratum varies between 5 and 25 feet with uncorrected
SPT N-values between 0 and 5.
Dense to very dense alluvial deposits were encountered in all borings following the organics (or
the looser alluvial deposits where organics were not present). Aside from boring SB-2, where
the dense alluvial deposits were penetrated and the boring terminated into bedrock, this stratum
was not fully penetrated and therefore its full thickness is unknown. At borings SB-1, the
thickness is 40 feet. This stratum is also coarse grained with a larger presence of gravelly
material and consists mainly of silty sands (SM), poorly graded sands (SP), and well graded
gravels (GW). Uncorrected SPT N-values are in the 27 to 77 range, with occasional refusal. It is
noted that this layer occasionally includes interbedded looser deposits, such as the one
encountered in boring SB-2 at the depth of 50 to 60 feet below ground surface, and is
characterized by uncorrected SPT N-values less than 10.
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3.3 Groundwater
Groundwater was not measured in the WSP borings due to the rotary wash method utilized in
the boring. Based on the HWA GDR and direct push sampling performed at the site,
groundwater was observed at about 5 feet below ground surface.
Groundwater levels at the site are subject to variations in groundwater basin management,
seasonal variation, nearby construction, irrigation, and other artificial and natural influences.
4 GEOTECHNICAL RECOMMENDATIONS
4.1 Preliminary Seismic Design Parameters
Recommendations for seismic design parameters are in accordance with the Sound Transit
Design Criteria that require a site classification based on AASHTO Guide Specification for
LRFD Seismic Bridge Design. According to AASHTO guidelines, sites characterized by peats or
highly organic clays with thickness greater than 10 feet are classified as Site Class F and would
require a site-specific evaluation. However, the Sound Transit Design Criteria state that “for
Conceptual and Preliminary Design of structures, local site effects of Site Class E may be used
to determine Site Class F design response spectra.” Consistent with the purpose of this report,
Site Class E is assumed and used to determine preliminary seismic design parameters. It is
noted that a site-specific response analysis may still be required for final design.
Table 4-1 summarizes the preliminary seismic design coefficients based on an assumed Site
Class E, a 7 percent probability of exceedance in 75 years (approximately 1,000-year return
period), and a 5 percent critical damping.
Other structures not covered in this geotechnical report (such as the planned parking garage
building) will need to follow different seismic design criteria that are not included in this report.
Table 4-1 Preliminary Seismic Design Coefficients
Site
Class
Mapped
Peak
Horizontal
Ground
Accel. PGA,
(g)
Mapped
Spectral
Accel. At
0.2 sec. Sa
(g)
Mapped
Spectral
Accel.
At 1.0
sec. Sa
(g)
Site Coefficients
Design
Spectral
Accel. At
0.2 sec.
Sds (g)
Design
Spectral
Accel.
At 0.2
sec. Sd1
(g)
Design
Peak
Horizontal
Ground
Accel. As
(g) Fa Fv Fpga
E 0.3433 0.988 0.282 1.015 2.889 1.335 1.002 0.815 0.577
NOTES:
1. g = Gravity
2. Fa = Short period sit coefficient
3. Fv = Long period site coefficient (1.0 second)
4. Fpga = peak ground acceleration site coefficient
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4.2 Liquefaction and Seismic Settlement
Liquefaction is a phenomenon in which saturated granular soils lose their inherent shear
strength due to build-up of excess pore water pressure induced by cyclic loading such as that
caused by an earthquake. Liquefaction potential is based on several factors, primarily: 1)
relative density and type of soil; 2) depth to groundwater, and 3) duration and intensity of
seismic shaking. Loose saturated granular materials (sands and low to non-plastic silts) are
most susceptible to liquefaction.
Liquefaction susceptibility mapping provided by King County identifies the site as moderate to
high susceptibility to liquefaction. Investigations at the site encountered shallow groundwater
depths and very loose to medium dense sands and silts. A preliminary liquefaction susceptibility
analysis indicates liquefiable soils are present at the site. Based off the preliminary analysis,
there is approximately 20 to 40 feet thickness of liquefiable material underlaying the site. The
estimated liquefaction-induced settlement varies depending on the boring data used, but it is
overall estimated to vary between 1 to 2 feet across the site.
4.3 Foundation Recommendations for Bus Shelters
When this report was prepared limited information was available regarding the location and
dimensions of potential bus shelter canopies. Therefore, it was assumed for purposes of this
report that the bus shelter canopies would be designed similar to those in King County Metro
Transit Passenger Facilities Improvements Standard Details (2020).
Discrete shallow spread and continuous foundations are not recommended for support of the
proposed bus shelter due to the presence of liquefiable soils that could cause severe damage to
the planned structure. A slab-on-grade foundation (structural mat) is recommended to support
the proposed bus shelter and mitigate the potential adverse impact of liquefaction-induced
settlements. An allowable bearing pressure of 1,000 psf may be utilized for design. Anticipated
immediate settlement is estimated to be on the order of ½ inch. Isolated areas where thicker
deposits of very loose alluvium are present may experience up to 1 inch of immediate
settlement. Long-term settlement due to consolidation of the organic material is also estimated
to be within ½ inch. Since the foundation is relatively small, differential settlement is anticipated
to be relatively small and on the order of ½ inch over the length of the foundation. These
preliminary settlement estimates assume a maximum applied pressure of 1,000 psf over the bus
shelter and that no fill will be placed to raise the existing grades. If new fills are placed over
large areas (such as in the case of a raise in grade elevations), large settlements may be
anticipated both short and long term. In this case, additional remediation measures will need to
be considered before placing any structure.
The slab-on-grade thickness should be determined by the project structural engineer and
designed to accommodate the anticipated liquefaction-induced seismic settlements. These
recommendations assume that the remedial site preparation recommendations (Section 4.6) are
incorporated into the design. Multiple interconnected slabs-on-grade are not recommended due
to the potential for liquefaction-induced settlements.
The slab-on-grade should be underlain by at least 4 inches of clean coarse sand or fine gravel
to provide a capillary moisture break and uniform support to the slab. A polyolefin vapor barrier
membrane may be utilized between the prepared subgrade and the bottom of the floor slab. The
project architect should design the vapor barrier membrane, including the polyolefin sheeting
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selection, water vapor permeance (ASTM F 1249), puncture resistance (ASTM D 1709), and
tensile strength (ASTM D 882).
A base friction coefficient of 0.35 may be used for footings poured directly on structural fill and
0.30 for footings poured on dense granular native soil.
Assuming a relatively level ground surface is present, the passive resistance of the soil can be
estimated based on a fully mobilized passive coefficient of 3.3. Full mobilization may be
conservatively assumed to occur when horizontal strains exceed 5% of the depth of the base of
the shallow foundation element. For intermediate strain values at which full mobilization is not
realized, linear interpolation between at-rest and ultimate passive resistance consistent with a
simplified, bilinear spring envelope or more advanced hyperbolic models may be used. The
passive resistance should not be considered for sliding resistance if there is any possibility of
removal of the soil in front of the foundation or if the loading considered is long term and creep
effects may reduce the available resistance.
4.4 Recommendations for Earth Retaining Structures
It is our understanding that the proposed grading at the site does not require any earth retaining
structures. In the event earth retaining structures are required, a flexible wall type such as a
mechanically stabilized earth (MSE) wall is recommended. The soft and loose soils present at
the subsurface would cause unacceptable differential settlement of rigid wall types.
4.5 Pavement Design and Recommendations
Design analyses were performed to develop recommendations for flexible and rigid pavement
sections at the SRTC site. Flexible pavement will be used in the parking garage access areas,
interim parking lot, and Lake Avenue. Rigid pavement will be used for the bus lanes and layover
area. The general approach to design, key assumptions, and recommended pavement sections
are discussed below. Detailed design inputs, assumptions, and calculations are presented in
Appendix F.
Logs of previous and recent borings completed at the site indicate that subgrade soils within
about 5 feet of the proposed pavement grade consist of predominantly loose sands and soft,
wet silts. These soils are expected to offer poor subgrade support of the proposed pavements.
Therefore, a relatively low subgrade resilient modulus of 3,300 psi was assumed for the site
soils. This value correlates to a modulus of subgrade reaction of approximately 100 pci for rigid
pavement design. It is recommended that laboratory CBR or R-value testing be conducted to
validate the subgrade strength value assumed for design.
Site grading will consist of up to about 1.5 feet of fill and up to about 3 feet of cut. Depth to
groundwater is estimated to be 5 feet. Groundwater fluctuations can occur.
Pavement design for the parking garage access area and bus lanes was performed in general
accordance with Sound Transit’s Design Criteria Manual (2018) and WSDOT’s Pavement
Design Policy (2018). Lake Avenue is located within the City of Renton jurisdiction. The City of
Renton (1998) code indicates that the Asphalt Institute’s (AI) Thickness Design Manual may be
used for flexible pavement design. The AI manual was not available at the time these analyses
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were performed. However, based on information presented on the AI website, the AASHTO
(1993) method is an acceptable approach to design.
Site-specific traffic data, including average daily traffic, percent trucks, growth rate, initial service
year, etc., were provided by the Traffic Engineer. Traffic loading in terms of 18-kip equivalent
single-axle loads (ESALs) was estimated for the project roadways using these site-specific
traffic data, assumed ESAL factors, and a design life of 20 years. Table 4-2 summarizes the
pavement types, design code, and estimated 18-kip ESAL values used for design.
Table 4-2 Design ESALs (20-year Design Life)
Section Roadway Pavement Type Design Code Design ESALs
1 Bus Lane Rigid Sound Transit (2018) 59,101,400
2 Parking Lot/Garage
Access
Flexible Sound Transit (2018) 236,700
3 Lake Avenue S Flexible City of Renton (1998) 16,351,600
Flexible pavement design was performed using WinPAS (2012) software based on the
AASHTO (1993) design procedure. Rigid pavement design was conducted using the Hall and
Smith design workbook based on the AASHTO 1998 procedure. The recommended pavement
sections are summarized in Table 4-3 and Table 4-4.
Table 4-3 Recommended Flexible Pavement Sections
Roadway
HMA (WSDOT Item
5-04), inches
CSBC (WSDOT
Item 4-04), inches
Total Thickness*,
inches
Parking Lot/Garage Access 5.0 8.0 13.0
Lake Avenue S 10.0 9.0 19.0
NOTE: *Pavement section shall be placed over properly prepared subgrade with geosynthetics as described in this report.
Table 4-4 Recommended Rigid Pavement Section
Roadway
PCCP (WSDOT
Item 5-05), inches
CSBC (WSDOT Item 4-04),
inches
Total Thickness*,
inches
Bus Lane 10.5 6 16.5
NOTE: *Pavement section shall be placed over properly prepared subgrade with geosynthetics as described in this report.
For rigid pavements, dowel bars for transverse joints and tie bars for longitudinal joints shall
meet WSDOT Standard Specifications. The recommended maximum transverse and
longitudinal joint spacings are 15 feet and 12 feet, respectively.
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Site soils are frost-susceptible. For frost-susceptible soils, the WSDOT Pavement Policy (2018)
recommends that pavement sections be equal to at least 50 percent of the frost depth. Based
on WSDOT (2018), the frost depth at the site is 15 inches. The recommended pavement
structures meet the frost depth requirement.
Considering the potential for groundwater fluctuations, it may be assumed that wet subgrade
soil conditions will be encountered during construction. These soils will require stabilization for
construction of a working platform, separation of the subgrade from the CSBC layer, and
reinforcement of the overall pavement section. It is recommended to place geosynthetics over
properly prepared subgrade prior to placing pavement materials. Geosynthetics shall meet the
requirements in Section 9-33 of the WSDOT Standard Specifications. To allow for both
separation and stabilization of soft soils, it is recommended to use a geotextile topped with a
geogrid layer. The geotextile shall meet the requirements for separation or stabilization specified
in Table 3 of Section 9-33 of the Standard Specifications. Approved geotextiles are listed in the
WSDOT Qualified Products List (QPL). The QPL does not include approved geogrids. It is
recommended that geogrids such as Tencate’s Mirafi BXG, Tensar’s TriAx, or Carthage Mills
GBX be used. Geotextile and geogrid must be placed in accordance with the manufacturer’s
recommendations. Precautions should be made during placement and compaction of the first lift
of base course to avoid damaging the geogrid.
4.6 Site Preparation and Grading
The existing building structures, pavements, buried pipes, hardscape, and landscaping not to
remain should be removed prior to the start of construction. All surficial vegetation and
deleterious material should be stripped and completely removed from the project site. Removal
of walkways, pavements, and various other light features (if required) would likely disrupt the
soils to a limited depth. Any remaining voids should be backfilled with approved and properly
compacted fill soils.
The in-situ soils are considered suitable for direct support of structural elements supporting the
planned lightly loaded structure if they are reworked and properly recompacted. However, the
shallowest zone of these deposits might have been disturbed by other construction activities,
wet/dry cycles, and burrowing animals. It is recommended that after ground clearing/grubbing
and existing features demolition that the top 12 inches of existing surficial soils be excavated,
moisture conditioned, and recompacted in place to a minimum relative compaction of 90 percent
(ASTM D1557). Before recompacting the excavated material, the exposed subgrade should
also be scarified to an additional depth of 12 inches (without removal) and recompacted in place
to at least 90 percent relative compaction (per ASTM D1557). Therefore, a total depth of 24
inches of recompacted soil shall be provided at the site underneath any structural element. The
lateral extent of the building footprint preparations should extend to at least 36 inches beyond
the lateral extent of the proposed foundation in all directions. The material should be moisture
conditioned to be placed between -2 to +2 percent of the optimum content. In paved areas, it is
recommended to place a geotextile topped with a geogrid layer upon properly prepared
subgrade, as discussed in Section 4.5.
The near surface materials consist of silty sands (SM) that are considered to be moisture
sensitive and can pose challenges during wet weather earthwork. General recommendations
relative to earthwork performed in wet weather or in wet conditions are presented below. Under
wet conditions, earthwork should be performed in small areas to minimize exposure to wet
weather. Excavation or the removal of unsuitable soil should be followed promptly by the
Stride program: I-405 corridor
Page 11 | AE 0054-17 | South Renton Transit Center Geotechnical Recommendation Report March 2022
placement and compaction of clean structural fill. The size and type of construction equipment
used might have to be limited to prevent soil disturbance.
Material used as structural fill should consist of clean granular soil with less than 5 percent
passing the No. 200 sieve based on wet sieving of the material fraction passing the ¾-inch
sieve. The fine-grained portion of the structural fill soils should be non-plastic.
The ground surface within the construction area should be graded to promote runoff of surface
water and to prevent the ponding of water. All exposed surfaces should be compacted on
completion or at the end of a shift to limit infiltration and softening. No material should be left in
a loose uncompacted state that would allow infiltration. Materials that have become wet and
softened must be either dried and recompacted or removed from the working area and replaced
with suitable fill.
4.7 Temporary Excavations
Temporary excavations are anticipated for construction of slab-on-grade footings and retaining
walls construction (if required). Temporary excavations should be laid back or shored in
accordance with U.S. Occupational Safety and Health Administration (OSHA) and any other
applicable regulations. Temporary excavations should be sloped no steeper than 1.5H:1V if
deeper than 4 feet corresponding to a soil type classification of OSHA Type C soil. If site
constraints prevent sloping of the excavations, shoring or worker protection measures such as
trench boxes should be used.
4.8 Structural Fill and Compaction
Fill placed beneath structures, pavements, or behind walls and reinforced zones should consist
of Select Borrow specified in Section 9-03.14(2) of the WSDOT Standard Specifications
(WSDOT, 2018).
Before any fill is placed, the subgrade should be free of ponded water. Fill should generally be
placed and compacted in 10-inch lifts if heavy equipment is used for compaction. If handheld
compaction equipment is used, lifts should generally be placed and compacted in 4-inch lifts.
Ultimately, the appropriate lift thickness and compaction methods will be determined in the field
by the contractor. The fill placement and compaction should be observed and tested by a
qualified geotechnical engineer or technician.
4.9 Groundwater Control
Dewatering is not anticipated for the construction of slab-on-grade footings and retaining walls.
If excavations or grading exceed 5 feet below ground surface, groundwater should be expected.
While groundwater monitoring at the site indicates groundwater 5 feet below existing ground
surface, seasonal variation should be anticipated, and it is possible that groundwater may be
encountered at higher elevations than historical monitoring has indicated.
Stride program: I-405 corridor
Page 12 | AE 0054-17 | South Renton Transit Center Geotechnical Recommendation Report March 2022
5 REFERENCES
Maps
Yount, James C. 1993. Geologic map of surficial deposits in the Seattle 30’ x 60’ quadrangle,
Washington.
Regulatory Guidance
American Association of State Highway and Transportation Officials (AASHTO). 1993. AASHTO
Guide for the Design of Pavement Structures.
American Association of State Highway and Transportation Officials (AASHTO). 2020. LRFD
Bridge Design Specifications. 9th Edition, 2020. 978-1-56051-738-2, LRFDBDS-9.
American Association of State Highway and Transportation Officials (AASHTO). 1998.
Supplement to the AASHTO Guide for the Design of Pavement Structures.
City of Renton (1998). Title IV Development Regulations, Revised and Compiled Ordinances,
Section 4-6-060.
Sound Transit. 2018. Design Criteria Manual. June 2018.
Washington State Department of Transportation (WSDOT). 2021. BEToolbox, Spectra, Version
6.1.0. Built on May 12, 2021.Washington State Department of Transportation (WSDOT). 2019.
Geotechnical Design Manual. M 46-03.12. July 2019.
Washington State Department of Transportation (WSDOT). 2018. Pavement Policy. September
2018.
Washington State Department of Transportation (WSDOT). 2018. Standard Specifications for
Road, Bridge, and Municipal Construction. M 41-10.
Reports
HWA Geosciences, Inc. (HWA). 2020a. I-405 Bus Rapid Transit (BRT) Project – Parking
Garages Geotechnical Data Report.
HWA Geosciences, Inc. (HWA). 2020b. I-405 Bus Rapid Transit (BRT) Project – Conceptual
Geotechnical Recommendations Report – Parking Garages.
AE 0054-17 | South Renton Transit Center Geotechnical
Recommendation Report
I-405 corridor
Detailed Figures:
A-1 | Site Location Map
A-2 | Regional Hazard Map
A-3 | Regional Geologic Map
A-4 | Geotechnical Exploration Plan
File Path: SITE LOCATION MAP
South Renton Transit CenterI-405 Bus Rapid Transit (BRT) Project
Burien TC to Lynnwood TC
By: C. BalesProj. No.: 160363P3Date: Aug 2021
A-1SCALE IN FEET
0 1000 2000 3000 4000
KEY
See Figure A-4
File Path: REGIONAL HAZARD MAP
South Renton Transit CenterI-405 Bus Rapid Transit (BRT) Project
Burien TC to Lynnwood TC
By: C. BalesProj. No.: 160363P3Date: Aug 2021
A-2SCALE IN FEET
0 1000 2000 3000 4000
KEY
= Very Low
LiquefactionHazard= Low to Moderate
= Moderate to High Misc.= Water Body
LandslideHazard= Scarps
= Scarps and Flanks
= Fans
= Lanslide Deposits
See Figure A-4
= High
See Figure A-4
File Path: REGIONAL GEOLOGIC MAP
South Renton Transit CenterI-405 Bus Rapid Transit (BRT) Project
Burien TC to Lynnwood TC
By: C. BalesProj. No.: 160363P3Date: Aug 2021
A-3SCALE IN FEET
0 500 1000 1500 2000
KEY
= Glaciolacustrine deposits = Renton Formation (bedrock)Qis Tr
= Stratified driftQsr= Alluvium (Cedar River)Qac= Artificial fill (general)af
= Artificial fill (urban/industrial)afm
QacQaw
Tta
Tr
Ttu
Ttu
Ti
Qaw
Ttu Tta
TtaTta
Ttl
Ttl
Ttl
Tr
af
afm
Qac
Qit
Qgt
Qu
Qpa
Qgt
Qlp
Qmc
Qgt
Qpa
Qac Qas
Qu
Qas
Qas
Qsr
Qpa
af
Qac
Qmc
Qu
Qlp
QlpQlm
Qu
Qas
Qas
Qg
Qac
Qlm
Qac
afTs
Tr
TsTr
Qmc
af
Tr
Qit
Qikaf
af
Tr Qsr
Qis
Qgt
Qik
Tt
Qpa
Qg
Qu
Qlp
Ts
Qu
Qiv
Qlm
Map Source
Mullineaux, D.R. 1965. Geologic Map of the Renton Quadrangle,
King County, Washington. Geologic Quadrangle Map GQ-405.
United States Geological Society.
File Path: GEOTECHNICAL EXPLORATION PLAN
South Renton Transit CenterI-405 Bus Rapid Transit (BRT) Project
Burien TC to Lynnwood TC
By: C. BalesProj. No.: 160363P3Date: Aug 2021
A-4SCALE IN FEET
0 50 100 150 200
KEY
= Previously Completed Boring (HWA Geosciences, 2019)= Geotechnical Boring Completed for This Phase
BH-8 [HWA]
RW-12 [WSP]
RW-11 [WSP]
RW-10 [WSP]
SB-1 [WSP]
SB-2 [WSP]
SH-4 [WSP]SH-5 [WSP]
BH-7 [HWA]
BH-10 [HWA]
BH-9 [HWA]
AE 0054-17 | South Renton Transit Center Geotechnical
Recommendation Report
I-405 corridor
Existing Geotechnical Information by Others
GS
AL
GS
S-1
S-2
S-3
S-4
S-5
S-6
S-7
S-8
2'' of HMA.
(HMA)
Very loose, brown, silty, gravelly, SAND, moist.
(FILL)
No recovery.
Very loose, brown, silty, sandy, GRAVEL, moist.
Very soft, gray to brown, sandy, SILT, moist. With gravel.
Brown organics scattered. Low recovery.
(ALLUVIUM)
Very loose, gray, silty, fine SAND, moist to wet. Two 1"
medium sand lenses.
Very stiff, gray, sandy, organic SILT, moist. With medium
sand lenses. 2" of dark brown organics.
Stiff, gray, sandy, SILT, moist. Scattered organics and
medium sand lenses. Water added to augers to counter
heave.
Same but soft. Scattered organics and 2" sand lenses. Silt
grades coarser than above and sample is wet.
Medium stiff, gray, sandy SILT, moist to wet. Scattered minor
organics, sample grades coarser with depth to fine clean sand
at toe.
1-1-1
1-1-1
0-0-0
0-0-0
6-9-9
2-4-8
1-2-1
2-3-5
SM
GM
ML
SM
OH
ML
BORING-DSM 2017-135-21.GPJ 11/27/19
FIGURE:PROJECT NO.:2017-135-21
Washington
I-405 Bus Rapid Transit (BRT) Project BH-07
PAGE: 1 of 2(blows/6 inches)GROUNDWATERPEN. RESISTANCELiquid LimitSYMBOL010203040 50
0 20 40 60 80 100SAMPLE TYPESAMPLE NUMBERNatural Water ContentUSCS SOIL CLASSWater Content (%)
NOTE: This log of subsurface conditions applies only at the specified location and on the date indicated
DESCRIPTION OTHER TESTSPlastic Limit
BORING:
and therefore may not necessarily be indicative of other times and/or locations.
(140 lb. weight, 30" drop)
Blows per foot
A-6
Standard Penetration Test
DEPTH(feet)0
5
10
15
20
25
30 ELEVATION(feet)DATE COMPLETED: 10/28/2019
DRILLING COMPANY: Holocene Drilling
DRILLING METHOD: HSA with Diedrich D-120
LOCATION: See Figure 2B
DATE STARTED: 10/28/2019
SAMPLING METHOD: SPT with Autohammer LOGGED BY: S. Khandaker
S-9
S-10
S-11
S-12
S-13
S-14
Very stiff, gray, sandy, SILT, wet. With rounded gravels at
end of sampler.
Medium dense, gray, silty, sandy, rounded GRAVEL, moist.
Same but dense. Low recovery.
Loose, orange to brown, silty, fine to medium sandy, rounded
GRAVEL, moist to wet. Heavily rust mottled.
Same but very dense. Low recovery.
Very dense, olive brown, sandy, round fine to coarse
GRAVEL, wet.
Borehole terminated at 56.5 feet below ground surface (bgs).
Ground water seepage observed from 9 feet bgs.
Borehole abandoned with bentonite chips.
6-12-17
9-10-10
15-16-16
2-1-4
12-28-24
34-34-37
GM
GP
BORING-DSM 2017-135-21.GPJ 11/27/19
FIGURE:PROJECT NO.:2017-135-21
Washington
I-405 Bus Rapid Transit (BRT) Project BH-07
PAGE: 2 of 2(blows/6 inches)GROUNDWATERPEN. RESISTANCELiquid LimitSYMBOL010203040 50
0 20 40 60 80 100SAMPLE TYPESAMPLE NUMBERNatural Water ContentUSCS SOIL CLASSWater Content (%)
NOTE: This log of subsurface conditions applies only at the specified location and on the date indicated
DESCRIPTION OTHER TESTSPlastic Limit
BORING:
and therefore may not necessarily be indicative of other times and/or locations.
(140 lb. weight, 30" drop)
Blows per foot
A-6
Standard Penetration Test
DEPTH(feet)30
35
40
45
50
55
60 ELEVATION(feet)DATE COMPLETED: 10/28/2019
DRILLING COMPANY: Holocene Drilling
DRILLING METHOD: HSA with Diedrich D-120
LOCATION: See Figure 2B
DATE STARTED: 10/28/2019
SAMPLING METHOD: SPT with Autohammer LOGGED BY: S. Khandaker
>>
>>
OC
AL
DS
OC
S-1
S-2
S-3
S-4
S-5
S-6
S-7a
S-7b
S-8
S-9
S-10
S-11
2'' of HMA.
(HMA)
Loose, brown, silty, gravelly, SAND, moist.
(FILL)
Loose, brown to gray at depth, silty, SAND, grading to sandy,
gravelly, SILT at toe, moist. Low recovery.
Very loose, gray, very silty, fine to medium SAND, moist.
Scattered rounded gravels.
Very loose, brown-gray, very silty, fine SAND, moist.
Scattered organics and gravels.
(ALLUVIUM)
Very soft, brown, sandy, SILT, moist. Low recovery.
Same. Sample grades less organic and less sandy.
Very soft, olive brown, elastic SILT, moist. Dark brown
organics and scattered gravels.
Medium dense, gray, slightly silty, fine SAND, moist.
Very soft, brown to gray, organic SILT, moist. Abundant
organics and 2" of dark brown peat.
Medium stiff, brown, PEAT, moist with abundant organics,
grading to a brown organic silt at toe of sample. Water added
to augurs to counter heave.
Medium dense, gray with brown organics, silty SAND, moist.
2" of peat near top, scattered organics.
Medium dense, gray, medium clean SAND, moist. Scattered
rounded gravels.
0-3-3
2-2-2
1-1-1
0-0-0
2-1-1
0-0-0
7-7-10
1-1-1
2-2-4
3-5-8
4-5-8
SM
SM
SM
MH
SP
SM
OH
PT
SM
SP
BORING-DSM 2017-135-21.GPJ 11/27/19
FIGURE:PROJECT NO.:2017-135-21
Washington
I-405 Bus Rapid Transit (BRT) Project BH-08
PAGE: 1 of 2(blows/6 inches)GROUNDWATERPEN. RESISTANCELiquid LimitSYMBOL010203040 50
0 20 40 60 80 100SAMPLE TYPESAMPLE NUMBERNatural Water ContentUSCS SOIL CLASSWater Content (%)
NOTE: This log of subsurface conditions applies only at the specified location and on the date indicated
DESCRIPTION OTHER TESTSPlastic Limit
BORING:
and therefore may not necessarily be indicative of other times and/or locations.
(140 lb. weight, 30" drop)
Blows per foot
A-7
Standard Penetration Test
DEPTH(feet)0
5
10
15
20
25
30
35
40
45 ELEVATION(feet)DATE COMPLETED: 10/29/2019
DRILLING COMPANY: Holocene Drilling
DRILLING METHOD: HSA with Diedrich D-120
LOCATION: See Figure 2B
DATE STARTED: 10/29/2019
SAMPLING METHOD: SPT with Autohammer LOGGED BY: S. Khandaker
GS
S-12
S-13
S-14
S-15
S-16
S-17
S-18
S-19
Same but dense. Sand grades coarser and sample is wet.
Same but medium dense. Sand grades coarser and sample
is wet. Rounded gravels at toe.
Same but dense.
Very dense, olive brown, sandy, rounded GRAVEL, moist.
Low recovery. Heave in sampler.
No recovery. Sampler filled with heave.
Dense, olive brown, medium to coarse sandy, rounded
GRAVEL, wet.
Hard, gray, SILT with sand, moist.
Very dense, 6" of gray to 4" of orange, fine SAND, moist.
Heavily rust mottled at contact. Minor organics observed.
Borehole terminated at 81.5 feet below ground surface (bgs).
Ground water seepage observed from 15 ft bgs.
Borehole abandoned with bentonite chips.
10-12-20
7-10-15
10-16-30
10-19-34
10-19-35
14-20-26
13-23-28
18-24-31
GP
ML
SP
BORING-DSM 2017-135-21.GPJ 11/27/19
FIGURE:PROJECT NO.:2017-135-21
Washington
I-405 Bus Rapid Transit (BRT) Project BH-08
PAGE: 2 of 2(blows/6 inches)GROUNDWATERPEN. RESISTANCELiquid LimitSYMBOL010203040 50
0 20 40 60 80 100SAMPLE TYPESAMPLE NUMBERNatural Water ContentUSCS SOIL CLASSWater Content (%)
NOTE: This log of subsurface conditions applies only at the specified location and on the date indicated
DESCRIPTION OTHER TESTSPlastic Limit
BORING:
and therefore may not necessarily be indicative of other times and/or locations.
(140 lb. weight, 30" drop)
Blows per foot
A-7
Standard Penetration Test
DEPTH(feet)45
50
55
60
65
70
75
80
85
90 ELEVATION(feet)DATE COMPLETED: 10/29/2019
DRILLING COMPANY: Holocene Drilling
DRILLING METHOD: HSA with Diedrich D-120
LOCATION: See Figure 2B
DATE STARTED: 10/29/2019
SAMPLING METHOD: SPT with Autohammer LOGGED BY: S. Khandaker
>>
>>
>>
>>
S-1
S-2
S-3
S-4
S-5
S-6
S-7
S-8
GS
AL
OC
SM
ML
OH
SM
SM
ML
6-6-4
2-3-3
1-1-1
0-0-0
0-0-0
2-2-2
2-3-5
1-1-1
2'' of HMA.
(HMA)
Loose, brown, silty, gravelly, SAND, moist.
(FILL)
Loose, gray to brown, slightly gravelly, silty, SAND, moist.
Grading to silt with depth.
Loose, olive gray to brown, slightly gravelly, very silty, fine to
medium SAND, moist. Minor rust mottling.
Very soft, gray, sandy, SILT, moist with dark brown organics
scattered. 3" of dark brown organics at top.
(ALLUVIUM)
Very soft, gray, fine sandy, SILT, moist to wet. Scattered
organics observed.
Very soft, gray, fine sandy, organic SILT, moist. 2" of dark
brown organics at 13.25 ft.
Very loose, gray, silty to slightly silty, medium to fine SAND,
wet. Grades to clean sand at toe.
Loose, gray, silty, SAND, moist with organics. 4 " of dark
brown organics. 2" of clean medium sand at toe.
Very soft, gray, sandy, SILT, moist. Grading towards an
organic silt. 2" sand lens.
0 20 40 60 80 100
Water Content (%)
Plastic Limit
(140 lb. weight, 30" drop)
Blows per foot
(blows/6 inches)USCS SOIL CLASSDESCRIPTION SAMPLE TYPESAMPLE NUMBERPEN. RESISTANCEOTHER TESTSPIEZOMETERStandard Penetration Test
A-8SYMBOLSCHEMATIC01020304050
Liquid Limit
BORING:
BH-09
PAGE: 1 of 2
Water Content (%)
Natural Water ContentNOTE: This log of subsurface conditions applies only at the specified location and on the date indicatedand therefore may not necessarily be indicative of other times and/or locations.
PZO-DSM 2017-135-21.GPJ 11/27/19
FIGURE:PROJECT NO.:2017-135-21
Washington
I-405 Bus Rapid Transit (BRT) ProjectDEPTH(feet)0
5
10
15
20
25
30 ELEVATION(feet)DATE COMPLETED: 10/28/2019
DRILLING COMPANY: Holocene Drilling
DRILLING METHOD: HSA with Diedrich D-120
LOCATION: See Figure 2B
DATE STARTED: 10/28/2019
SAMPLING METHOD: SPT with Autohammer LOGGED BY: S. Khandaker
S-9
S-10a
S-10b
S-11
ALOL
ML
SP
GP
GM
2-3-6
2-5-9
9-37-38
Stiff, gray, organic, SILT, moist. Sand lenses in top 6".
Stiff, gray, plastic SILT, wet.
Medium dense, gray, clean, medium SAND, wet.
Harder drilling noted by drillers.
Very dense, gray, slightly silty to silty, sandy, rounded
GRAVEL, wet. 4 feet of heave observed. Low recovery.
Boring terminated at 45 feet below ground surface (bgs).
Ground water seepage observed from 17 feet bgs.
2-inch diameter well casing installed to 40 feet.
Well ID: BLU 045
0 20 40 60 80 100
Water Content (%)
Plastic Limit
(140 lb. weight, 30" drop)
Blows per foot
(blows/6 inches)USCS SOIL CLASSDESCRIPTION SAMPLE TYPESAMPLE NUMBERPEN. RESISTANCEOTHER TESTSPIEZOMETERStandard Penetration Test
A-8SYMBOLSCHEMATIC01020304050
Liquid Limit
BORING:
BH-09
PAGE: 2 of 2
Water Content (%)
Natural Water ContentNOTE: This log of subsurface conditions applies only at the specified location and on the date indicatedand therefore may not necessarily be indicative of other times and/or locations.
PZO-DSM 2017-135-21.GPJ 11/27/19
FIGURE:PROJECT NO.:2017-135-21
Washington
I-405 Bus Rapid Transit (BRT) ProjectDEPTH(feet)30
35
40
45
50
55
60 ELEVATION(feet)DATE COMPLETED: 10/28/2019
DRILLING COMPANY: Holocene Drilling
DRILLING METHOD: HSA with Diedrich D-120
LOCATION: See Figure 2B
DATE STARTED: 10/28/2019
SAMPLING METHOD: SPT with Autohammer LOGGED BY: S. Khandaker
>>
AL
OC
CN
S-1
S-2
S-3
S-4
S-5
S-6
S-7
S-8
S-9
S-10
S-11a
S-11b
S-11c
2'' of HMA. (HMA)
Driller notes petroleum odor.
Medium dense, brown to olive gray, slightly gravelly, silty, fine
to medium SAND, moist. Metal and wood debris. Minor
organics.
(FILL)
Loose, olive gray to black, gravelly, very silty, fine to medium
SAND, moist.
Very soft, gray, sandy, plastic SILT, moist. Scattered minor
organics such as roots and bark.
(ALLUVIUM)
Very loose, gray, silty to clean, medium, poorly-graded SAND,
moist to wet.
Very soft, brown, organic SILT, moist. Abundant organics.
Medium sand lenses.
Same. Scattered gravels.
Very loose, gray, clean, medium to fine SAND, moist. Water
added to augers to counter heave.
Very loose, brown and gray, organic to not organic, silty
SAND, moist. 2" of fine sand lens.
Soft, gray, slightly sandy, SILT, moist interlayered with brown,
organic silt. 30% organic silt.
Same but medium stiff. Sample is 20% organic silt. 3" layer
of gray, clean, medium sand at toe.
No recovery.
Hard, gray, sandy, gravelly, SILT, moist. Graded coarser with
depth, minor organics at top of sample.
5-10-8
4-3-2
0-0-0
0-0-0
1-1-1
1-2-2
0-0-0
1-2-2
2-3-3
2-3-5
8-28-35
SM
ML
SP
OH
SP
SM
ML
BORING-DSM 2017-135-21.GPJ 11/27/19
FIGURE:PROJECT NO.:2017-135-21
Washington
I-405 Bus Rapid Transit (BRT) Project BH-10
PAGE: 1 of 2(blows/6 inches)GROUNDWATERPEN. RESISTANCELiquid LimitSYMBOL010203040 50
0 20 40 60 80 100SAMPLE TYPESAMPLE NUMBERNatural Water ContentUSCS SOIL CLASSWater Content (%)
NOTE: This log of subsurface conditions applies only at the specified location and on the date indicated
DESCRIPTION OTHER TESTSPlastic Limit
BORING:
and therefore may not necessarily be indicative of other times and/or locations.
(140 lb. weight, 30" drop)
Blows per foot
A-9
Standard Penetration Test
DEPTH(feet)0
5
10
15
20
25
30
35
40
45 ELEVATION(feet)DATE COMPLETED: 10/30/2019
DRILLING COMPANY: Holocene Drilling
DRILLING METHOD: HSA with Diedrich D-120
LOCATION: See Figure 2B
DATE STARTED: 10/30/2019
SAMPLING METHOD: SPT with Autohammer LOGGED BY: S. Khandaker
>>
GS
S-12
S-13
S-14
S-15
S-16
S-17
S-18
S-19
Dense, gray, slightly silty, fine to coarse sandy, rounded
GRAVEL, moist.
Dense, gray, well graded, GRAVEL with silt and sand, wet.
Medium dense, gray, medium to coarse sandy, fine to coarse
GRAVEL, wet.
Same but dense. 3" of rust mottled orange at toe.
Dense, olive gray, fine to coarse sandy, rounded GRAVEL to
gravelly SAND, moist.
No recovery. Heave in sampler.
Very dense, gray, sandy, fine to coarse GRAVEL, moist. 3" of
gray silt with scattered organics.
Dense, olive gray, medium to coarse sandy, rounded
GRAVEL, wet.
Borehole terminated at 81.5 feet below ground surface (bgs).
Ground water seepage observed from 11 ft bgs.
Borehole abandoned with bentonite chips.
17-20-26
10-20-22
7-9-10
10-17-26
14-19-25
14-20-28
28-33-44
18-20-23
GP
GM
GW
GM
GP
GP
GP
GM
GP
BORING-DSM 2017-135-21.GPJ 11/27/19
FIGURE:PROJECT NO.:2017-135-21
Washington
I-405 Bus Rapid Transit (BRT) Project BH-10
PAGE: 2 of 2(blows/6 inches)GROUNDWATERPEN. RESISTANCELiquid LimitSYMBOL010203040 50
0 20 40 60 80 100SAMPLE TYPESAMPLE NUMBERNatural Water ContentUSCS SOIL CLASSWater Content (%)
NOTE: This log of subsurface conditions applies only at the specified location and on the date indicated
DESCRIPTION OTHER TESTSPlastic Limit
BORING:
and therefore may not necessarily be indicative of other times and/or locations.
(140 lb. weight, 30" drop)
Blows per foot
A-9
Standard Penetration Test
DEPTH(feet)45
50
55
60
65
70
75
80
85
90 ELEVATION(feet)DATE COMPLETED: 10/30/2019
DRILLING COMPANY: Holocene Drilling
DRILLING METHOD: HSA with Diedrich D-120
LOCATION: See Figure 2B
DATE STARTED: 10/30/2019
SAMPLING METHOD: SPT with Autohammer LOGGED BY: S. Khandaker
>>
BH-03,S-5 12.5 14.0 13.1 68.9 28.6 2.5 GP Yellowish-brown, poorly graded GRAVEL with sand
BH-03,S-11 40.0 40.8 24.5 36 23 13 CL Gray, lean CLAY
BH-03,S-14 55.0 56.0 25.9 0.4 18.8 80.8 ML Dark gray, SILT with sand
BH-04,S-5 12.5 14.0 15.9 1.1 51.3 47.6 SM Yellowish-brown, silty SAND
BH-04,S-8 25.0 26.5 24.1 60.9 39.1 SM Gray, silty SAND
BH-04,S-11 40.0 41.5 18.8 19.3 76.7 4.0 SP Dark gray, poorly graded SAND with gravel
BH-05,S-5 12.5 14.0 12.0 5.5 82.0 12.6 SM Yellowish-brown, silty SAND
BH-05,S-11 40.0 41.5 30.6 15.9 84.1 ML Brown, SILT with sand
BH-05,S-13 50.0 51.5 25.3 33 22 11 CL Gray, lean CLAY
BH-05,S-22 95.0 96.5 20.4 54.1 45.9 SM Gray, silty SAND
BH-06,S-3 7.5 9.0 19.1 20.8 37.6 41.6 SM Brown, silty SAND with gravel
BH-06,S-6 15.0 16.5 4.3 64.8 27.6 7.7 GP-GM Olive-brown, poorly graded GRAVEL with silt and sand
BH-06,S-9 30.0 31.5 31.8 50 29 21 ML-MH Olive-brown, SILT/elastic SILT
BH-07,S-4 10.0 11.5 31.5 0.4 59.1 40.4 SM Dark grayish-brown, silty SAND
BH-07,S-5 12.5 14.0 75.1 75 41 34 OH Dark grayish-brown, organic SILT
BH-07,S-8 25.0 26.5 33.3 0.1 42.0 57.9 ML Dark grayish-brown, sandy SILT
BH-08,S-3 7.5 9.0 31.6 3.3 SM Dark grayish-brown, silty SAND
BH-08,S-6 15.0 16.5 55.4 52 32 20 MH Olive-brown, elastic SILT(feet)TOP DEPTHSAMPLE DESCRIPTION
Notes:ASTM SOILMOISTURECONTENT (%)ORGANIC% FINESSPECIFIC GRAVITYEXPLORATIONDESIGNATION1. This table summarizes information presented elsewhere in the report and should be used in conjunction with the report test, other graphs and tables, and the exploration logs.
2. The soil classifications in this table are based on ASTM D2487 and D2488 as applicable.
MATERIAL PROPERTIES
B1
PAGE: 1 of 2
SUMMARY OF
LIMITS (%)
ATTERBERG
BOTTOM DEPTHCONTENT (%)% SAND% GRAVELPIPLLL CLASSIFICATION(feet)2017-135-21PROJECT NO.:
INDEX MATSUM 2 2017-135-21.GPJ 11/20/19
FIGURE:
I-405 Bus Rapid Transit (BRT) Project
Washington
BH-08,S-10 35.0 36.5 44.0 3.4 SM Dark grayish-brown, silty SAND
BH-08,S-18 75.0 76.5 29.5 0.1 25.7 74.3 ML Dark grayish-brown, SILT with sand
BH-09,S-4 10.0 11.5 44.2 1.3 33.0 65.7 ML Dark grayish-brown, sandy SILT
BH-09,S-5 12.5 14.0 57.8 76 58 18 OH Olive-brown, organic SILT
BH-09,S-7 20.0 21.5 71.9 9.0 SM Dark grayish-brown, silty SAND with organics
BH-09,S-9 30.0 31.5 57.7 47 29 18 OL Dark grayish-brown, organic SILT
BH-10,S-3 7.5 9.0 41.2 42 29 13 ML Dark grayish-brown, SILT
BH-10,S-7 20.0 21.5 94.5 12.0 SM Olive-brown, silty SAND with organics
BH-10,S-11b 40.5 41.0 36.7 ML Dark gray, SILT with sand
BH-10,S-13 50.0 51.5 9.6 56.6 37.6 5.8 GW-GM Dark grayish-brown, well-graded GRAVEL with silt and sand(feet)TOP DEPTHSAMPLE DESCRIPTION
Notes:ASTM SOILMOISTURECONTENT (%)ORGANIC% FINESSPECIFIC GRAVITYEXPLORATIONDESIGNATION1. This table summarizes information presented elsewhere in the report and should be used in conjunction with the report test, other graphs and tables, and the exploration logs.
2. The soil classifications in this table are based on ASTM D2487 and D2488 as applicable.
MATERIAL PROPERTIES
B2
PAGE: 2 of 2
SUMMARY OF
LIMITS (%)
ATTERBERG
BOTTOM DEPTHCONTENT (%)% SAND% GRAVELPIPLLL CLASSIFICATION(feet)2017-135-21PROJECT NO.:
INDEX MATSUM 2 2017-135-21.GPJ 11/20/19
FIGURE:
I-405 Bus Rapid Transit (BRT) Project
Washington
0
10
20
30
40
50
60
70
80
90
100
0.0010.010.1110
GRAIN SIZE IN MILLIMETERS
50
SAMPLE
S-6
S-4
S-8
15.0 - 16.5
10.0 - 11.5
25.0 - 26.5
#10
27.6
59.1
42.0
30
CLASSIFICATION OF SOIL- ASTM D2487 Group Symbol and Name
U.S. STANDARD SIEVE SIZES
SAND
B6
Coarse
#60#40#20
Fine Coarse
SYMBOL
Gravel%
3"1-1/2"PERCENT FINER BY WEIGHT#4 #200
64.8
0.4
0.1
Sand%
(GP-GM) Olive-brown, poorly graded GRAVEL with silt and sand
(SM) Dark grayish-brown, silty SAND
(ML) Dark grayish-brown, sandy SILT
Fines%
0.00050.005
CLAY
BH-06
BH-07
BH-07
SILT
3/4"
GRAVEL
0.05
5/8"
70
#100
0.5
4
31
33
50
Medium Fine
3/8"
5
PI
90
10
% MC LL PLDEPTH ( ft.)
PARTICLE-SIZE ANALYSIS
OF SOILS
METHOD ASTM D6913
7.7
40.4
57.9
2017-135-21PROJECT NO.:
HWAGRSZ 2017-135-21.GPJ 11/20/19
FIGURE:
I-405 Bus Rapid Transit (BRT) Project
Washington
0
10
20
30
40
50
60
70
80
90
100
0.0010.010.1110
GRAIN SIZE IN MILLIMETERS
50
SAMPLE
S-18
S-4
S-13
75.0 - 76.5
10.0 - 11.5
50.0 - 51.5
#10
25.7
33.0
37.6
30
CLASSIFICATION OF SOIL- ASTM D2487 Group Symbol and Name
U.S. STANDARD SIEVE SIZES
SAND
B7
Coarse
#60#40#20
Fine Coarse
SYMBOL
Gravel%
3"1-1/2"PERCENT FINER BY WEIGHT#4 #200
0.1
1.3
56.6
Sand%
(ML) Dark grayish-brown, SILT with sand
(ML) Dark grayish-brown, sandy SILT
(GW-GM) Dark grayish-brown, well-graded GRAVEL with silt and sand
Fines%
0.00050.005
CLAY
BH-08
BH-09
BH-10
SILT
3/4"
GRAVEL
0.05
5/8"
70
#100
0.5
29
44
10
50
Medium Fine
3/8"
5
PI
90
10
% MC LL PLDEPTH ( ft.)
PARTICLE-SIZE ANALYSIS
OF SOILS
METHOD ASTM D6913
74.3
65.7
5.8
2017-135-21PROJECT NO.:
HWAGRSZ 2017-135-21.GPJ 11/20/19
FIGURE:
I-405 Bus Rapid Transit (BRT) Project
Washington
0
10
20
30
40
50
60
70
80
0 20 40 60 80 100 120
CL-ML
LIQUID LIMIT, PLASTIC LIMIT AND
PLASTICITY INDEX OF SOILS
METHOD ASTM D4318
(CL) Gray, lean CLAY
(CL) Gray, lean CLAY
(ML-MH) Olive-brown, SILT/elastic SILT
(OH) Dark grayish-brown, organic SILT
(MH) Olive-brown, elastic SILT
(OH) Olive-brown, organic SILT
SYMBOL SAMPLE
13
11
21
34
20
18
LIQUID LIMIT (LL)
LL PL PICLASSIFICATION % MC
24
25
32
75
55
58
DEPTH (ft)% Fines
OL
BH-03
BH-05
BH-06
BH-07
BH-08
BH-09
S-11
S-13
S-9
S-5
S-6
S-5
36
33
50
75
52
76
23
22
29
41
32
58
40.0 - 40.8
50.0 - 51.5
30.0 - 31.5
12.5 - 14.0
15.0 - 16.5
12.5 - 14.0PLASTICITY INDEX (PI)OR ML
OL OR CL OH OR CH
OH OR MH
B82017-135-21PROJECT NO.:
HWAATTB ORG (LL TO 120) 2017-135-21.GPJ 11/20/19
FIGURE:
I-405 Bus Rapid Transit (BRT) Project
Washington
0
10
20
30
40
50
60
70
80
0 20 40 60 80 100 120
CL-ML
LIQUID LIMIT, PLASTIC LIMIT AND
PLASTICITY INDEX OF SOILS
METHOD ASTM D4318
(OL) Dark grayish-brown, organic SILT
(ML) Dark grayish-brown, SILT
SYMBOL SAMPLE
18
13
LIQUID LIMIT (LL)
LL PL PICLASSIFICATION % MC
58
41
DEPTH (ft)% Fines
OL
BH-09
BH-10
S-9
S-3
47
42
29
29
30.0 - 31.5
7.5 - 9.0PLASTICITY INDEX (PI)OR ML
OL OR CL OH OR CH
OH OR MH
B92017-135-21PROJECT NO.:
HWAATTB ORG (LL TO 120) 2017-135-21.GPJ 11/20/19
FIGURE:
I-405 Bus Rapid Transit (BRT) Project
Washington
I-405 BRT
BH-8 Sample No.:S-7B 20.75-21.5 feetSoil Description:silty SAND
Soil Color:Dark grayish-brown Strain rate:0.6 % per min.Soil Group Symbol:SM Soil Specific Gravity:2.75 (assumed)
Normal Stress (psf)1250.00 2500.00 5000.00 AveragePeak Stress (psf)1007.93 1808.48 4035.96
Residual Stress (psf)1021.50 2204.60 3772.60 Cohesion phi Angle
Initial Moisture Content (%):29.0 29.0 29.0 29.0 psf (degrees)Wet Unit Weight (pcf):125.3 123.0 124.2 124.2 Peak 0.0 39.3
Dry Unit Weight (pcf):97.1 95.4 96.3 96.3Calculated Void Ratio 0.767 0.799 0.782 0.783
Calculated Porosity 0.434 0.444 0.439 0.439Calculated Saturation (%)104.1 99.8 102.0 102.0
Final Moisture Content (%)26.8 27.3 27.5 27.2
Figure B-11
Indicated Strength Parameters
HWA GEOSCIENCES INC. Materials Testing LaboratoryDirect Shear Test of Soils Under Consolidated Drained Conditions (ASTM D 3080)
2017-135-21
Sample Point:
Project Name:Project Number:
Sample Depth:
0.00
500.00
1000.00
1500.00
2000.00
2500.00
3000.00
3500.00
4000.00
4500.00
0.00 1000.00 2000.00 3000.00 4000.00 5000.00 6000.00Shear Stress (psf)Normal Stress (psf)
Peak Peak Trend
0.00
500.00
1000.00
1500.00
2000.00
2500.00
3000.00
3500.00
4000.00
4500.00
0.00 2.00 4.00 6.00 8.00 10.00 12.00 14.00 16.00 18.00Shear Stress (psf)% Strain
Normal Stress: 1250.00 Normal Stress: 2500.0 Normal Stress: 5000.0
-0.010-0.0050.0000.0050.0100.0150.0200.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0 18.0
Dilation/Contraction(inches)Checked By: S. Greene
CONSOLIDATION TEST REPORT
Cv(ft.2/day)0.3
0.8
1.3
1.8
2.3
2.8
Applied Pressure - ksf
0.1 1 10Percent Strain20
18
16
14
12
10
8
6
4
2
0
Natural Dry Dens.LL PI Sp. Gr.USCS AASHTO Initial Void
Saturation Moisture (pcf)Ratio
92.3 %36.7 %82.8 2.65 ML 1.055
Dark gray, SILT with sand
2017-135
I-405 BRT Project
B-13
MATERIAL DESCRIPTION
Project No.Client:Remarks:
Project:
Source of Sample: BH-10 Depth: 40.5 Sample Number: S-11b
Figure
AE 0054-17 | South Renton Transit Center Geotechnical
Recommendation Report
I-405 corridor
Boring Logs
50
S
S
S
ST
S
S
SM
MH
OL
SP
Very loose to loose, gray, Silty Sand (SM);moist; fine grained sand; nonplastic fines; trace
wood fragments.
Very soft, gray to dark brown, Elastic Silt (MH);moist; medium plasticity.
Very soft, dark brown, Organic Silt (OL); moist;medium plasticity; organics.
Medium dense, gray, Poorly Graded Sand (SP);
moist; medium grained sand.
63.7
163.8
21 89.3
1-2-3(5)
1-1-1(2)
0-0-0(0)
0-0-0
(0)
6-8-8
(16)
BORING DIA.:
START TIME:START DATE:
C. Bales
Truck Rig
Rotary Wash
Austin
Vertical
Holt
July 22, 2021
HAMMER CALIBRATION-ENERGY TRANSFER RATIO:Sample TypeSampleLab Tests
VISUAL CLASSIFICATION
4.5"Plasticity IndexLOGGER:Drill Rate Min/ft.ORIENTATION:
BORING TYPE:
RIG TYPE:
I-405 Bus Rapid Transit and Bus Base North
unknown
1105
Elevation in FeetDepth in FeetDRILLER FIRM:
DRILLER:
PROJECT NAME:Graphical LogCOMPLETION DATE:
STATION/OFFSET:
REFERENCE:
COORDINATES:
COORDINATE SYS:
SURFACE ELEV. (FT):
VERTICAL DATUM:
PROJECT #:
REMARKS
Unified SoilClassificationPercent passing#200 SieveMoisture Content (%)of Dry WeightDry Density (pcf)Liquid Limit (%)SEGMENT:
COMPLETION TIME:
Renton Transit Center
N/A
47.47245942 -122.216286
1415
160363P3.003
July 22, 2021
NAVD88
26
NAD83
Not Surveyed
Blow CountTIMEDEPTH(ft)
GROUNDWATER
0
5
10
15
20
1 of
25.0
20.0
15.0
10.0
3Page
BORING LOG I.D.:
B - Bulk SampleS - 2" O.D. 1.38" I.D. Split Spoon SampleST - Shelby Tube Sample (Thin Wall Tube)
NQ - 2.98" O.D. Core SampleMC - Modified California Sample
NR - No Recovery
DATE
METHOD
unknown unknown~5
SAMPLE TYPE (Continued Next Page)
unknown
RW-10
S
ST
MC
S
S
ML
GP
Very soft, grayish brown to gray Silt with Sand
(ML); moist; fine grained sand; low to mediumplasticity fines; trace organics.
Grades medium stiff.
Medium dense to very dense, dark bluish gray,
Poorly Graded Gravel with Sand (GP); wet; fineto coarse, subrounded to subangular gravel.
6255.9
0-1-0(1)
3-3-5(8)
21-32-26(58)
13-9-11
(20)Depth in FeetDrill Rate Min/ft.Elevation in FeetPROJECT:GraphicalLogSampleSample TypeLab Tests
Liquid Limit (%)Plasticity IndexI-405 Bus Rapid Transit and Bus Base North
Unified SoilClassificationVISUAL CLASSIFICATION
PROJECT LOCATION:
REMARKS
Dry Density (pcf)Moisture Content(%) of Dry WeightPercent passing#200 SieveRenton Transit Center
Blow CountTIMEDEPTH(ft)
GROUNDWATER
20
25
30
35
40
45
2 of
5.0
0.0
-5.0
-10.0
-15.0
3Page
BORING LOG I.D.:
B - Bulk SampleS - 2" O.D. 1.38" I.D. Split Spoon SampleST - Shelby Tube Sample (Thin Wall Tube)
NQ - 2.98" O.D. Core SampleMC - Modified California Sample
NR - No Recovery
DATE
METHOD
unknown unknown~5
SAMPLE TYPE (Continued Next Page)
unknown
RW-10
S GP
End of drilling at 46.5 ft.
34-43-33(76)Depth in FeetDrill Rate Min/ft.Elevation in FeetPROJECT:GraphicalLogSampleSample TypeLab Tests
Liquid Limit (%)Plasticity IndexI-405 Bus Rapid Transit and Bus Base North
Unified SoilClassificationVISUAL CLASSIFICATION
PROJECT LOCATION:
REMARKS
Dry Density (pcf)Moisture Content(%) of Dry WeightPercent passing#200 SieveRenton Transit Center
Blow CountTIMEDEPTH(ft)
GROUNDWATER
45
50
55
60
65
70
3 of
-20.0
-25.0
-30.0
-35.0
-40.0
3Page
BORING LOG I.D.:
B - Bulk SampleS - 2" O.D. 1.38" I.D. Split Spoon SampleST - Shelby Tube Sample (Thin Wall Tube)
NQ - 2.98" O.D. Core SampleMC - Modified California Sample
NR - No Recovery
DATE
METHOD
unknown unknown~5
SAMPLE TYPE
unknown
RW-10
S
S
S
S
S
ST
SM
SP
OL
SP
ML
PT
Medium dense, bluish gray, Silty Sand withGravel (SM); moist; hydrocarbon odor
Loose, gray, Poorly Graded Sand (SP); wet;trace gravel; fine to medium grained sand.
Very soft, dark brown, Organc Silt (OL); moist;
organics throughout.
Very loose, bluish gray, Poorly Graded Sand
(SP); wet; fine to medium grained sand.
Very soft, gray, Silt with Sand (ML); wet; finegrained sand; low to medium plasticity fines.
Very soft, dark brown, Peat (PT); moist;abundant organics.
170.1
191.4
3-8-16(24)
2-2-2(4)
1-1-0(1)
0-1-1(2)
0-0-0
(0)
BORING DIA.:
START TIME:START DATE:
C. Bales
Truck Rig
Rotary Wash
Austin
Vertical
Holt
July 23, 2021
HAMMER CALIBRATION-ENERGY TRANSFER RATIO:Sample TypeSampleLab Tests
VISUAL CLASSIFICATION
4.5"Plasticity IndexLOGGER:Drill Rate Min/ft.ORIENTATION:
BORING TYPE:
RIG TYPE:
I-405 Bus Rapid Transit and Bus Base North
unknown
1257
Elevation in FeetDepth in FeetDRILLER FIRM:
DRILLER:
PROJECT NAME:Graphical LogCOMPLETION DATE:
STATION/OFFSET:
REFERENCE:
COORDINATES:
COORDINATE SYS:
SURFACE ELEV. (FT):
VERTICAL DATUM:
PROJECT #:
REMARKS
Unified SoilClassificationPercent passing#200 SieveMoisture Content (%)of Dry WeightDry Density (pcf)Liquid Limit (%)SEGMENT:
COMPLETION TIME:
Renton Transit Center
N/A
47.47236803 -122.2151093
Not recorded
160363P3.003
July 23, 2021
NAVD88
27
NAD83
Not Surveyed
Blow CountTIMEDEPTH(ft)
GROUNDWATER
0
5
10
15
20
1 of
25.0
20.0
15.0
10.0
2Page
BORING LOG I.D.:
B - Bulk SampleS - 2" O.D. 1.38" I.D. Split Spoon SampleST - Shelby Tube Sample (Thin Wall Tube)
NQ - 2.98" O.D. Core SampleMC - Modified California Sample
NR - No Recovery
DATE
METHOD
unknown unknown~5
SAMPLE TYPE (Continued Next Page)
unknown
RW-11
42
S
S
S
S
S
PT
ML
OL
SP-SM
GP
Very soft, dark brown, Peat (PT); moist;
abundant organics.
Very soft, gray, Sandy Silt (ML); wet; finegrained sand.
Very soft, olive brown, Organic Silt (OL); moist;abundant organics.
Very loose to loose, bluish gray, Poorly GradedSand (SP) to Silty Sand (SM); wet.
Dense, bluish gray, Poorly Graded Gravel withSand (GP); wet; mostly fine, subangular to
subrounded gravel.
End of drilling at 41.5 ft.
38.6 13 88.6
0-0-1(1)
0-0-2
(2)
0-0-2(2)
1-3-2(5)
18-21-26
(47)Depth in FeetDrill Rate Min/ft.Elevation in FeetPROJECT:GraphicalLogSampleSample TypeLab Tests
Liquid Limit (%)Plasticity IndexI-405 Bus Rapid Transit and Bus Base North
Unified SoilClassificationVISUAL CLASSIFICATION
PROJECT LOCATION:
REMARKS
Dry Density (pcf)Moisture Content(%) of Dry WeightPercent passing#200 SieveRenton Transit Center
Blow CountTIMEDEPTH(ft)
GROUNDWATER
20
25
30
35
40
45
2 of
5.0
0.0
-5.0
-10.0
-15.0
2Page
BORING LOG I.D.:
B - Bulk SampleS - 2" O.D. 1.38" I.D. Split Spoon SampleST - Shelby Tube Sample (Thin Wall Tube)
NQ - 2.98" O.D. Core SampleMC - Modified California Sample
NR - No Recovery
DATE
METHOD
unknown unknown~5
SAMPLE TYPE
unknown
RW-11
S
S
MC
S
ST
SM
SP
SM
ML
ML
Silty Sand with Gravel (SM).
Very loose to loose, dark gray to black, PoorlyGraded Sand with Gravel (SP); wet; roundedgravel; coarse grained sand.
Very loose, bluish gray, Silty Sand (SM); wet;mostly fine grained sand.
Very soft, gray mottled brown Silt with sand
(ML); moist; low plasticity fines
Very soft, gray Silt (ML) to Elastic Silt (MH);moist; little sand; medium plasticity fines.
38.7 29.5
4-3-2(5)
2-0-1(1)
1-1-2(3)
0-0-1
(1)
BORING DIA.:
START TIME:START DATE:
C. Bales
Truck Rig
Rotary Wash
Austin
Vertical
Holt
August 4, 2021
HAMMER CALIBRATION-ENERGY TRANSFER RATIO:Sample TypeSampleLab Tests
VISUAL CLASSIFICATION
4.5"Plasticity IndexLOGGER:Drill Rate Min/ft.ORIENTATION:
BORING TYPE:
RIG TYPE:
I-405 Bus Rapid Transit and Bus Base North
unknown
0835
Elevation in FeetDepth in FeetDRILLER FIRM:
DRILLER:
PROJECT NAME:Graphical LogCOMPLETION DATE:
STATION/OFFSET:
REFERENCE:
COORDINATES:
COORDINATE SYS:
SURFACE ELEV. (FT):
VERTICAL DATUM:
PROJECT #:
REMARKS
Unified SoilClassificationPercent passing#200 SieveMoisture Content (%)of Dry WeightDry Density (pcf)Liquid Limit (%)SEGMENT:
COMPLETION TIME:
Renton Transit Center
N/A
47.47236564 -122.2143319
1135
160363P3.003
August 4, 2021
NAVD88
27
NAD83
Not Surveyed
Blow CountTIMEDEPTH(ft)
GROUNDWATER
0
5
10
15
20
1 of
25.0
20.0
15.0
10.0
3Page
BORING LOG I.D.:
B - Bulk SampleS - 2" O.D. 1.38" I.D. Split Spoon SampleST - Shelby Tube Sample (Thin Wall Tube)
NQ - 2.98" O.D. Core SampleMC - Modified California Sample
NR - No Recovery
DATE
METHOD
unknown unknown~5
SAMPLE TYPE (Continued Next Page)
unknown
RW-12
111
S
S
S
MC
S
SM
ML
OL
ML
OH
OL
SM
SP
Very loose, bluish gray, Silty Sand (SM); wet;
fine grained sand.
Very soft, grayish brown, Silt with Sand (ML);
moist; low plasticity fines.
Very Soft, dark brown, Organic Silty (OL);moist; abundant organics.
Very Soft, gray, Silt with Sand (ML) to Silt (ML);moist; fine grained sand; medium plasticity
fines.
Soft to medium stiff, gray, Organic Silt (OH);
moist; medium to high plasticity fines; organicsthroughout.
Very soft, yellowish brown, Organic Silt (OL);moist; low plasticity fines.
Medium dense, bluish gray, Silty Sand (SM);moist; mostly fine sand.
Dense, gray, Poorly Graded Sand (SP); moist;medium to coarse grained sand.
80.9 40 81.8
1-1-1(2)
1-1-1
(2)
1-1-0(1)
2-2-4(6)
2-8-16
(24)Depth in FeetDrill Rate Min/ft.Elevation in FeetPROJECT:GraphicalLogSampleSample TypeLab Tests
Liquid Limit (%)Plasticity IndexI-405 Bus Rapid Transit and Bus Base North
Unified SoilClassificationVISUAL CLASSIFICATION
PROJECT LOCATION:
REMARKS
Dry Density (pcf)Moisture Content(%) of Dry WeightPercent passing#200 SieveRenton Transit Center
Blow CountTIMEDEPTH(ft)
GROUNDWATER
20
25
30
35
40
45
2 of
5.0
0.0
-5.0
-10.0
-15.0
3Page
BORING LOG I.D.:
B - Bulk SampleS - 2" O.D. 1.38" I.D. Split Spoon SampleST - Shelby Tube Sample (Thin Wall Tube)
NQ - 2.98" O.D. Core SampleMC - Modified California Sample
NR - No Recovery
DATE
METHOD
unknown unknown~5
SAMPLE TYPE (Continued Next Page)
unknown
RW-12
MC
S
SP-SM
GP
Dense, bluish gray, Poorly Graded Sand (SP);
moist; medium grained sand.
Dense, bluish gray, Poorly Graded Gravel withSand (GP); wet; mostly fine, subangular gravel.
End of drilling at 51.5 ft.
37.5 6.519-13-19(32)
22-19-21
(40)Depth in FeetDrill Rate Min/ft.Elevation in FeetPROJECT:GraphicalLogSampleSample TypeLab Tests
Liquid Limit (%)Plasticity IndexI-405 Bus Rapid Transit and Bus Base North
Unified SoilClassificationVISUAL CLASSIFICATION
PROJECT LOCATION:
REMARKS
Dry Density (pcf)Moisture Content(%) of Dry WeightPercent passing#200 SieveRenton Transit Center
Blow CountTIMEDEPTH(ft)
GROUNDWATER
45
50
55
60
65
70
3 of
-20.0
-25.0
-30.0
-35.0
-40.0
3Page
BORING LOG I.D.:
B - Bulk SampleS - 2" O.D. 1.38" I.D. Split Spoon SampleST - Shelby Tube Sample (Thin Wall Tube)
NQ - 2.98" O.D. Core SampleMC - Modified California Sample
NR - No Recovery
DATE
METHOD
unknown unknown~5
SAMPLE TYPE
unknown
RW-12
S
S
S
S
S
MC
SM
SM
Cased to 5 ft Very Dense, Gray, Silty Sand (SM); moist; traceto few, subrounded to subangular, fine gravel;
fine to medium sand; yellowish brown oxidationstaining.
Very Dense, gray, Silty Sand (SM); wet; fine
sand; nonplastic fines; rapid dilatency
15.6
12.2
25
14.2
22-50/4"
38-50/1"
50
24-50
50
70-50/3"
BORING DIA.:
START TIME:START DATE:
C. Bales
Track Rig
HSA / Mud Rotary
Erick, Mike & Tom
Vertical
Holocene
June 17, 2021
HAMMER CALIBRATION-ENERGY TRANSFER RATIO:Sample TypeSampleLab Tests
VISUAL CLASSIFICATION
Plasticity IndexLOGGER:Drill Rate Min/ft.ORIENTATION:
BORING TYPE:
RIG TYPE:
I-405 Bus Rapid Transit and Bus Base North
unknown
0820
Elevation in FeetDepth in FeetDRILLER FIRM:
DRILLER:
PROJECT NAME:Graphical LogCOMPLETION DATE:
STATION/OFFSET:
REFERENCE:
COORDINATES:
COORDINATE SYS:
SURFACE ELEV. (FT):
VERTICAL DATUM:
PROJECT #:
REMARKS
Unified SoilClassificationPercent passing#200 SieveMoisture Content (%)of Dry WeightDry Density (pcf)Liquid Limit (%)SEGMENT:
COMPLETION TIME:
Kingsgate Park and Ride
N/A
1130
160363P3.003
June 17, 2021
NAVD88
~170
NAD83
Not Surveyed
Blow CountTIMEDEPTH(ft)
GROUNDWATER
0
5
10
15
20
1 of 3Page
BORING LOG I.D.:
B - Bulk SampleS - 2" O.D. 1.38" I.D. Split Spoon SampleST - Shelby Tube Sample (Thin Wall Tube)
NQ - 2.98" O.D. Core SampleMC - Modified California Sample
NR - No Recovery
DATE
METHOD
SAMPLE TYPE (Continued Next Page)
RW-13
44
S
S
S
S
S
SP
CL
SM
Very dense, gray, Poorly-Graded Sand (SP);
wet; medium sand.
Hard, gray, lean Clay (CL); moist; mediumplasticity fines.
Very dense, gray, Silty Sand (SM); wet; fine to
medium sand; nonplastic fines.
18.8
29.1
29.7 21
76.1
68.3
27-50
13-38-50
(88)
14-21-25(46)
17-27-45(72)
50/5"Depth in FeetDrill Rate Min/ft.Elevation in FeetPROJECT:GraphicalLogSampleSample TypeLab Tests
Liquid Limit (%)Plasticity IndexI-405 Bus Rapid Transit and Bus Base North
Unified SoilClassificationVISUAL CLASSIFICATION
PROJECT LOCATION:
REMARKS
Dry Density (pcf)Moisture Content(%) of Dry WeightPercent passing#200 SieveKingsgate Park and Ride
Blow CountTIMEDEPTH(ft)
GROUNDWATER
20
25
30
35
40
45
2 of 3Page
BORING LOG I.D.:
B - Bulk SampleS - 2" O.D. 1.38" I.D. Split Spoon SampleST - Shelby Tube Sample (Thin Wall Tube)
NQ - 2.98" O.D. Core SampleMC - Modified California Sample
NR - No Recovery
DATE
METHOD
SAMPLE TYPE (Continued Next Page)
RW-13
S
S
SM Very dense, gray, Silty Sand (SM); wet; fine to
medium sand; nonplastic fines.
End of drilling at 50 ft.
31-35-48(83)
31-50/5"Depth in FeetDrill Rate Min/ft.Elevation in FeetPROJECT:GraphicalLogSampleSample TypeLab Tests
Liquid Limit (%)Plasticity IndexI-405 Bus Rapid Transit and Bus Base North
Unified SoilClassificationVISUAL CLASSIFICATION
PROJECT LOCATION:
REMARKS
Dry Density (pcf)Moisture Content(%) of Dry WeightPercent passing#200 SieveKingsgate Park and Ride
Blow CountTIMEDEPTH(ft)
GROUNDWATER
45
50
55
60
65
70
3 of 3Page
BORING LOG I.D.:
B - Bulk SampleS - 2" O.D. 1.38" I.D. Split Spoon SampleST - Shelby Tube Sample (Thin Wall Tube)
NQ - 2.98" O.D. Core SampleMC - Modified California Sample
NR - No Recovery
DATE
METHOD
SAMPLE TYPE
RW-13
S
S
S
S
ST
S
SM
7-5-4
(9)
3-1-0(1)
1-0-0(0)
0-2-2(4)
0-1-4(5)
Asphalt
Very loose to loose, yellowish brown Silty Sandwith Gravel (SM); moist; angular gravel.
Very soft to soft, dark brown, Elastic Silt (MH);moist; fine grained sand; medium to highplasticity fines; organics throughout.
40 936 74.5
BORING DIA.:
START TIME:START DATE:
C. Bales
Truck Rig
Rotary Wash
Austin
Vertical
Holt
7/19/2021
HAMMER CALIBRATION-ENERGY TRANSFER RATIO:Sample TypeSampleLab Tests
VISUAL CLASSIFICATION
4.5"Plasticity IndexLOGGER:Drill Rate Min/ft.ORIENTATION:
BORING TYPE:
RIG TYPE:
I-405 Bus Rapid Transit and Bus Base North
unknown
0820
Elevation in FeetDepth in FeetDRILLER FIRM:
DRILLER:
PROJECT NAME:Graphical LogCOMPLETION DATE:
STATION/OFFSET:
REFERENCE:
COORDINATES:
COORDINATE SYS:
SURFACE ELEV. (FT):
VERTICAL DATUM:
PROJECT #:
REMARKS
Unified SoilClassificationPercent passing#200 SieveMoisture Content (%)of Dry WeightDry Density (pcf)Liquid Limit (%)SEGMENT:
COMPLETION TIME:
Renton Transit Center
N/A
47.47213434 -122.2162898
1230
160363P3.003
7/20/2021
NAVD88
27
NAD83
Not Surveyed
Blow CountDATE
METHOD unknown
unknown~5 unknown
SAMPLE TYPE (Continued Next Page)
TIMEDEPTH(ft)
GROUNDWATER
0
5
10
15
20
1 of
25.0
20.0
15.0
10.0
5Page
BORING LOG I.D.:SB-1
B - Bulk SampleS - 2" O.D. 1.38" I.D. Split Spoon SampleST - Shelby Tube Sample (Thin Wall Tube)NQ - 2.98" O.D. Core SampleMC - Modified California SampleNR - No Recovery
ML
Soft, brownish gray Silt with Sand (ML); moist;fine sand; low to medium plasticity fines; traceorganics.
MH
S
S
S
ST
S
SP-SM
OH
SM
4-3-3(6)
0-1-3(4)
1-2-2(4)
37-30-29(59)
Loose, gray Poorly graded Sand with Silt(SP-SM); wet; mostly fine grained sand; traceorganics; faint hydrocarbon odor.
Soft, olive brown Sandy Organic Silt (OH);moist; medium to high plasticity fines.
Loose, Gray, Silty Sand (SM).
No Recovery.
134.4
25.795.8
2992 62.3Depth in FeetDrill Rate Min/ft.Elevation in FeetPROJECT:GraphicalLogSampleSample TypeLab Tests
Liquid Limit (%)Plasticity IndexI-405 Bus Rapid Transit and Bus Base North
Unified SoilClassificationVISUAL CLASSIFICATION
PROJECT LOCATION:
REMARKS
Dry Density (pcf)Moisture Content(%) of Dry WeightPercent passing#200 SieveRenton Transit Center
Blow CountDATE
METHOD unknown
unknown~5 unknown
SAMPLE TYPE (Continued Next Page)
TIMEDEPTH(ft)
GROUNDWATER
20
25
30
35
40
45
2 of
5.0
0.0
-5.0
-10.0
-15.0
5Page
BORING LOG I.D.:SB-1
B - Bulk SampleS - 2" O.D. 1.38" I.D. Split Spoon SampleST - Shelby Tube Sample (Thin Wall Tube)NQ - 2.98" O.D. Core SampleMC - Modified California SampleNR - No Recovery
S
S
S
S
MC
SP
SP
GW-GM
9-5-4(9)
10-10-10(20)
6-6-3(9)
20-17-13(30)
55-53-63(108)
Loose to medium dense, gray, Poorly GradedSand (SP); moist; medium grained sand.
Loose to dense, gray, Poorly Graded Sand withGravel (SP); wet; fine, subrounded gravel;medium to coarse grained sand.
Very Dense, olive gray, Well Graded Gravel withSand and Silt (GW-GM); wet; fine to coarse,subrounded gravel; coarse grained sand.
6.1Depth in FeetDrill Rate Min/ft.Elevation in FeetPROJECT:GraphicalLogSampleSample TypeLab Tests
Liquid Limit (%)Plasticity IndexI-405 Bus Rapid Transit and Bus Base North
Unified SoilClassificationVISUAL CLASSIFICATION
PROJECT LOCATION:
REMARKS
Dry Density (pcf)Moisture Content(%) of Dry WeightPercent passing#200 SieveRenton Transit Center
Blow CountDATE
METHOD unknown
unknown~5 unknown
SAMPLE TYPE (Continued Next Page)
TIMEDEPTH(ft)
GROUNDWATER
45
50
55
60
65
70
3 of
-20.0
-25.0
-30.0
-35.0
-40.0
5Page
BORING LOG I.D.:SB-1
B - Bulk SampleS - 2" O.D. 1.38" I.D. Split Spoon SampleST - Shelby Tube Sample (Thin Wall Tube)NQ - 2.98" O.D. Core SampleMC - Modified California SampleNR - No Recovery
S
S
S
S
S
GW-GM
SP
GP
ML
23-7-5(12)
14-17-18(35)
19-18-18(36)
50
50/3"
Dense to very dense, gray, Poorly Graded Sandwith Gravel (SP); wet; fine to coarse gravel;coarse grained sand.
Very dense, dark gray, Poorly Graded Gravelwith Sand (GP); moist; fine to coarse,subangular gravel.Depth in FeetDrill Rate Min/ft.Elevation in FeetPROJECT:GraphicalLogSampleSample TypeLab Tests
Liquid Limit (%)Plasticity IndexI-405 Bus Rapid Transit and Bus Base North
Unified SoilClassificationVISUAL CLASSIFICATION
PROJECT LOCATION:
REMARKS
Dry Density (pcf)Moisture Content(%) of Dry WeightPercent passing#200 SieveRenton Transit Center
Blow CountDATE
METHOD unknown
unknown~5 unknown
SAMPLE TYPE (Continued Next Page)
TIMEDEPTH(ft)
GROUNDWATER
70
75
80
85
90
95
4 of
-45.0
-50.0
-55.0
-60.0
-65.0
5Page
BORING LOG I.D.:SB-1
B - Bulk SampleS - 2" O.D. 1.38" I.D. Split Spoon SampleST - Shelby Tube Sample (Thin Wall Tube)NQ - 2.98" O.D. Core SampleMC - Modified California SampleNR - No Recovery
S
S
GP32-21-39(60)
48-33-24(57)
Very dense, dark gray, Poorly Graded Gravelwith Sand (GP); moist; fine to coarse,subangular gravel.
End of drilling at 105 ft.Depth in FeetDrill Rate Min/ft.Elevation in FeetPROJECT:GraphicalLogSampleSample TypeLab Tests
Liquid Limit (%)Plasticity IndexI-405 Bus Rapid Transit and Bus Base North
Unified SoilClassificationVISUAL CLASSIFICATION
PROJECT LOCATION:
REMARKS
Dry Density (pcf)Moisture Content(%) of Dry WeightPercent passing#200 SieveRenton Transit Center
Blow CountDATE
METHOD unknown
unknown~5 unknown
SAMPLE TYPE
TIMEDEPTH(ft)
GROUNDWATER
95
100
105
110
115
120
5 of
-70.0
-75.0
-80.0
-85.0
-90.0
5Page
BORING LOG I.D.:SB-1
B - Bulk SampleS - 2" O.D. 1.38" I.D. Split Spoon SampleST - Shelby Tube Sample (Thin Wall Tube)NQ - 2.98" O.D. Core SampleMC - Modified California SampleNR - No Recovery
S
S
S
ST
S
S
ASPHALT
SM
SP
ML
MH
1-3-1
(4)
1-2-1(3)
0-0-0(0)
0-0-0(0)
0-2-3(5)
Asphalt
Very loose, dark bluish gray, Silty Sand withGravel (SM); moist; fine, angular gravel
Very loose, dark bluish gray, Poorly GradedSand; moist; medium grained sand; abundantorganics
Very soft, brownish gray Silt with Sand (ML);moist; fine grained sand; medium plasticityfines; trace organics.
Very soft to medium stiff, dark brown, ElasticSilt (MH); moist; fine grained sand; highplasticity fines; organics throughout.
52.1 1746 97.1
BORING DIA.:
START TIME:START DATE:
C. Bales
Truck Rig
Rotary Wash
Austin
Vertical
Holt
7/20/2021
HAMMER CALIBRATION-ENERGY TRANSFER RATIO:Sample TypeSampleLab Tests
VISUAL CLASSIFICATION
4.5"Plasticity IndexLOGGER:Drill Rate Min/ft.ORIENTATION:
BORING TYPE:
RIG TYPE:
I-405 Bus Rapid Transit and Bus Base North
unknown
1405
Elevation in FeetDepth in FeetDRILLER FIRM:
DRILLER:
PROJECT NAME:Graphical LogCOMPLETION DATE:
STATION/OFFSET:
REFERENCE:
COORDINATES:
COORDINATE SYS:
SURFACE ELEV. (FT):
VERTICAL DATUM:
PROJECT #:
REMARKS
Unified SoilClassificationPercent passing#200 SieveMoisture Content (%)of Dry WeightDry Density (pcf)Liquid Limit (%)SEGMENT:
COMPLETION TIME:
Renton Transit Center
N/A
47.47181785 -122.2171586
1315
160363P3.003
7/21/2021
NAVD88
27
NAD83
Not Surveyed
Blow CountDATE
METHOD unknown
unknown~5 unknown
SAMPLE TYPE (Continued Next Page)
TIMEDEPTH(ft)
GROUNDWATER
0
5
10
15
20
1 of
25.0
20.0
15.0
10.0
4Page
BORING LOG I.D.:SB-2
B - Bulk SampleS - 2" O.D. 1.38" I.D. Split Spoon SampleST - Shelby Tube Sample (Thin Wall Tube)NQ - 2.98" O.D. Core SampleMC - Modified California SampleNR - No Recovery
S
S
S
MC
S
MH
GP
GW-GM
GP
0-1-3(4)
20-9-18(27)
8-20-35(55)
27-25-17(52)
7-21-23(44)
Very soft to medium stiff, dark brown, ElasticSilt (MH); moist; fine grained sand; highplasticity fines; organics throughout.
Dense to very dense, bluish gray, PoorlyGraded Gravel with Sand (GP) to Poorly Gradedsand with Gravel (SP); moist to wet; mediumgrained sand.
Dense, gray, Poorly Graded Sand with Gravel(SP) to Poorly Graded Gravel with Sand (GP);wet; subrounded gravel; coarse grained sand.
Dense to very dense, bluish gray, PoorlyGraded Gravel (GP); wet; coarse, angular torounded gravel; little sand.
57.3
8.7
1451
6.2Depth in FeetDrill Rate Min/ft.Elevation in FeetPROJECT:GraphicalLogSampleSample TypeLab Tests
Liquid Limit (%)Plasticity IndexI-405 Bus Rapid Transit and Bus Base North
Unified SoilClassificationVISUAL CLASSIFICATION
PROJECT LOCATION:
REMARKS
Dry Density (pcf)Moisture Content(%) of Dry WeightPercent passing#200 SieveRenton Transit Center
Blow CountDATE
METHOD unknown
unknown~5 unknown
SAMPLE TYPE (Continued Next Page)
TIMEDEPTH(ft)
GROUNDWATER
20
25
30
35
40
45
2 of
5.0
0.0
-5.0
-10.0
-15.0
4Page
BORING LOG I.D.:SB-2
B - Bulk SampleS - 2" O.D. 1.38" I.D. Split Spoon SampleST - Shelby Tube Sample (Thin Wall Tube)NQ - 2.98" O.D. Core SampleMC - Modified California SampleNR - No Recovery
MC
S
S
S
S
GP
SM
Sandstone
65-61-47(126)
3-3-7(10)
6-4-4(8)
4-2-2(4)
50/2"
Loose, bluish gray, Silty Sand (SM); moist;mostly fine sand; nonplastic to low plasticityfines; some organics.
Sandstone [Renton Formation]Severely weathered; light yellowish brown;moist.
28.4 44.4Depth in FeetDrill Rate Min/ft.Elevation in FeetPROJECT:GraphicalLogSampleSample TypeLab Tests
Liquid Limit (%)Plasticity IndexI-405 Bus Rapid Transit and Bus Base North
Unified SoilClassificationVISUAL CLASSIFICATION
PROJECT LOCATION:
REMARKS
Dry Density (pcf)Moisture Content(%) of Dry WeightPercent passing#200 SieveRenton Transit Center
Blow CountDATE
METHOD unknown
unknown~5 unknown
SAMPLE TYPE (Continued Next Page)
TIMEDEPTH(ft)
GROUNDWATER
45
50
55
60
65
70
3 of
-20.0
-25.0
-30.0
-35.0
-40.0
4Page
BORING LOG I.D.:SB-2
B - Bulk SampleS - 2" O.D. 1.38" I.D. Split Spoon SampleST - Shelby Tube Sample (Thin Wall Tube)NQ - 2.98" O.D. Core SampleMC - Modified California SampleNR - No Recovery
S 50/1"Moderately to slightly weathered; dark bluishgray
End of drilling at 70 ft.Depth in FeetDrill Rate Min/ft.Elevation in FeetPROJECT:GraphicalLogSampleSample TypeLab Tests
Liquid Limit (%)Plasticity IndexI-405 Bus Rapid Transit and Bus Base North
Unified SoilClassificationVISUAL CLASSIFICATION
PROJECT LOCATION:
REMARKS
Dry Density (pcf)Moisture Content(%) of Dry WeightPercent passing#200 SieveRenton Transit Center
Blow CountDATE
METHOD unknown
unknown~5 unknown
SAMPLE TYPE
TIMEDEPTH(ft)
GROUNDWATER
70
75
80
85
90
95
4 of
-45.0
-50.0
-55.0
-60.0
-65.0
4Page
BORING LOG I.D.:SB-2
B - Bulk SampleS - 2" O.D. 1.38" I.D. Split Spoon SampleST - Shelby Tube Sample (Thin Wall Tube)NQ - 2.98" O.D. Core SampleMC - Modified California SampleNR - No Recovery
S
S
S
MC
S
ST
ML
SM
SM
PT
Very soft, gray Silt (ML); wet; some fine grainedsand; low to medium plasticity fines.
Loose, dark gray, Silty Sand (SM); wet; fine to
medium grained sand; trace organics.
Very loose, bluish gray, Silty Sand (SM); wet;fine grained sand.
Very soft, brown, Peat (PT); moist; medium to
high plasticity fines.
36.8
223.5
1-1-1(2)
1-0-0(0)
1-0-1(1)
3-4-5(9)
0-0-0
(0)
BORING DIA.:
START TIME:START DATE:
C. Bales
Truck Rig
Rotary Wash
Austin
Vertical
Holt
July 23, 2021
HAMMER CALIBRATION-ENERGY TRANSFER RATIO:Sample TypeSampleLab Tests
VISUAL CLASSIFICATION
4.5"Plasticity IndexLOGGER:Drill Rate Min/ft.ORIENTATION:
BORING TYPE:
RIG TYPE:
I-405 Bus Rapid Transit and Bus Base North
unknown
0900
Elevation in FeetDepth in FeetDRILLER FIRM:
DRILLER:
PROJECT NAME:Graphical LogCOMPLETION DATE:
STATION/OFFSET:
REFERENCE:
COORDINATES:
COORDINATE SYS:
SURFACE ELEV. (FT):
VERTICAL DATUM:
PROJECT #:
REMARKS
Unified SoilClassificationPercent passing#200 SieveMoisture Content (%)of Dry WeightDry Density (pcf)Liquid Limit (%)SEGMENT:
COMPLETION TIME:
Renton Transit Center
N/A
47.47221108 -122.2159353
1145
160363P3.003
July 23, 2021
NAVD88
26
NAD83
Not Surveyed
Blow CountTIMEDEPTH(ft)
GROUNDWATER
0
5
10
15
20
1 of
25.0
20.0
15.0
10.0
2Page
BORING LOG I.D.:
B - Bulk SampleS - 2" O.D. 1.38" I.D. Split Spoon SampleST - Shelby Tube Sample (Thin Wall Tube)
NQ - 2.98" O.D. Core SampleMC - Modified California Sample
NR - No Recovery
DATE
METHOD
unknown unknown~5
SAMPLE TYPE (Continued Next Page)
unknown
SH-4
Organic content = 19.2%
64S
S
S
S
S
OH
OL
MH
PT
SM
GP
Very soft, dark brown, organic Silt (OH); wet;
medium to high plasticity fines; abundantorganics.
Soft, dark brown, organic Silt (OL); moist; low tomedium plasticity fines; abundant organics
Soft, gray, Elastic Silt (MH); moist; little finegrained sand; medium to high plasticity fines.
Soft, moist, Peat (PT); moist; abundantorganics.
Very loose, bluish gray, Silty Sand (SM); wet;
fine grained sand; trace organics.
Dense, bluish gray, Poorly Graded Gravel (GP);wet; mostly fine, subangular gravel
End of drilling at 41.5 ft.
73.3
115.2
21 90.20-0-2(2)
2-2-3
(5)
0-1-3(4)
0-2-2(4)
14-13-18
(31)Depth in FeetDrill Rate Min/ft.Elevation in FeetPROJECT:GraphicalLogSampleSample TypeLab Tests
Liquid Limit (%)Plasticity IndexI-405 Bus Rapid Transit and Bus Base North
Unified SoilClassificationVISUAL CLASSIFICATION
PROJECT LOCATION:
REMARKS
Dry Density (pcf)Moisture Content(%) of Dry WeightPercent passing#200 SieveRenton Transit Center
Blow CountTIMEDEPTH(ft)
GROUNDWATER
20
25
30
35
40
45
2 of
5.0
0.0
-5.0
-10.0
-15.0
2Page
BORING LOG I.D.:
B - Bulk SampleS - 2" O.D. 1.38" I.D. Split Spoon SampleST - Shelby Tube Sample (Thin Wall Tube)
NQ - 2.98" O.D. Core SampleMC - Modified California Sample
NR - No Recovery
DATE
METHOD
unknown unknown~5
SAMPLE TYPE
unknown
SH-4
Organic content = 15.5%
36
S
S
S
S
S
S
SM
SM
ML
OL
SM
OL
Loose, dark gray, Silty Sand with Gravel (SM);moist; some organics; slight hydrocarbon odor.
Very loose, bluish gray, Silty Sand (SM); wet;mostly fine sand.
Very soft, bluish gray, Sandy Silt (ML); wet; finegrained sand low plasticity fines.
Very soft, dark brown, Organic Silt (OL); moist;
abundant organics.
Very loose, bluish gray, Silty Sand (SM); wet;
fine grained sand.
Very soft, dark brown, Organic Silt (OL); wet;abundant organics.
49.6
106.5
6 75
3-4-3(7)
0-0-0(0)
0-0-0(0)
1-0-1(1)
1-1-1
(2)
0-0-0
(0)
BORING DIA.:
START TIME:START DATE:
C. Bales
Truck Rig
Rotary Wash
Austin
Vertical
Holt
July 22, 2021
HAMMER CALIBRATION-ENERGY TRANSFER RATIO:Sample TypeSampleLab Tests
VISUAL CLASSIFICATION
4.5"Plasticity IndexLOGGER:Drill Rate Min/ft.ORIENTATION:
BORING TYPE:
RIG TYPE:
I-405 Bus Rapid Transit and Bus Base North
unknown
1500
Elevation in FeetDepth in FeetDRILLER FIRM:
DRILLER:
PROJECT NAME:Graphical LogCOMPLETION DATE:
STATION/OFFSET:
REFERENCE:
COORDINATES:
COORDINATE SYS:
SURFACE ELEV. (FT):
VERTICAL DATUM:
PROJECT #:
REMARKS
Unified SoilClassificationPercent passing#200 SieveMoisture Content (%)of Dry WeightDry Density (pcf)Liquid Limit (%)SEGMENT:
COMPLETION TIME:
Renton Transit Center
N/A
47.4721971 -122.2152283
Not recorded
160363P3.003
July 22, 2021
NAVD88
26
NAD83
Not Surveyed
Blow CountTIMEDEPTH(ft)
GROUNDWATER
0
5
10
15
20
1 of
25.0
20.0
15.0
10.0
2Page
BORING LOG I.D.:
B - Bulk SampleS - 2" O.D. 1.38" I.D. Split Spoon SampleST - Shelby Tube Sample (Thin Wall Tube)
NQ - 2.98" O.D. Core SampleMC - Modified California Sample
NR - No Recovery
DATE
METHOD
unknown unknown~5
SAMPLE TYPE (Continued Next Page)
unknown
SH-5
58
S
S
S
OL
SM
OH
PT
Very loose, bluish gray, Silty Sand (SM), wet,fine grained sand.
Very soft, brown and gray, Organic Silt withSand (OH); moist; little fine grained sand; low to
medium plasticity fines; trace organics.
Very soft, dark brown, Peat (PT); abundantorganics.
End of drilling at 32 ft.
62.7 5 84.9
5-1-2(3)
0-1-2
(3)
0-0-2(2)Depth in FeetDrill Rate Min/ft.Elevation in FeetPROJECT:GraphicalLogSampleSample TypeLab Tests
Liquid Limit (%)Plasticity IndexI-405 Bus Rapid Transit and Bus Base North
Unified SoilClassificationVISUAL CLASSIFICATION
PROJECT LOCATION:
REMARKS
Dry Density (pcf)Moisture Content(%) of Dry WeightPercent passing#200 SieveRenton Transit Center
Blow CountTIMEDEPTH(ft)
GROUNDWATER
20
25
30
35
40
45
2 of
5.0
0.0
-5.0
-10.0
-15.0
2Page
BORING LOG I.D.:
B - Bulk SampleS - 2" O.D. 1.38" I.D. Split Spoon SampleST - Shelby Tube Sample (Thin Wall Tube)
NQ - 2.98" O.D. Core SampleMC - Modified California Sample
NR - No Recovery
DATE
METHOD
unknown unknown~5
SAMPLE TYPE
unknown
SH-5
AE 0054-17 | South Renton Transit Center Geotechnical
Recommendation Report
I-405 corridor
Geophysical Survey Report
DOWNHOLE SHEAR WAVE SEISMIC SURVEY
REPORT
BORINGS SB-1 AND SB-2
I-405 BUS RAPID TRANSIT and
BUS OPERATIONS & MAINTENANCE FACILITY
RENTON, WASHINGTON
FOR
WSP USA, INC.
SEATTLE, WASHINGTON
WSP Project Number: 160363P3
September 13, 2021
PHILIP H. DUOOS
GEOPHYSICAL CONSULTANT
1
1
Philip H. Duoos Geophysical Consultant
September 13, 2021 Our Ref: 1363-21
Mr. Cole Bales
WSP USA Inc.
999 Third Avenue, Suite 3200
Seattle, WA 98104
REPORT: Downhole Seismic Shear Wave Survey
Borings SB-1 and SB-2
I-405 Bus Rabid Transit and Bus Operations & Maintenance Facility
Renton, Washington
WSP Project No.: 160363P3
Dear Mr. Bales:
This letter report summarizes the results of the downhole seismic survey in Borings SB-1 and SB-2 at
the subject site located in Renton, Washington. Field work was performed on Monday July 26. The
approximate locations of the borings are shown on Figure 1.
At both locations, shear wave data were measured in the boring at 2.5-foot intervals, and
compressional wave data were measured at 5-foot intervals. The field measurements were
referenced to the top of the rim of the protective flush-mount cover housing which is at the ground
surface.
The depths are to the sensor location in the borehole tool. The bottom of the tool is about
1.3 feet below the sensor location. Boring SB-1 near the northeast corner of the existing building was
completed at a depth of 105 feet and the deepest data point is at 103.75 feet. Boring SB-2 is located
near the southeast corner, completed at a depth of 70 feet with the deepest data point at 68.75 feet.
Boring SB-2 encountered Renton Formation sandstone at a depth of approximately 63 feet.
INTERPRETATION RESULTS
Table 1 shows the shear wave velocities and the compressional wave velocities for both borings. The
tables show the interpreted depth range for each velocity layer and the interpreted seismic wave
velocity.
For Boring SB-1, the shear wave data and compressional wave data with interpreted velocity layers
are provided in Figures 2 and 3, respectively. For Boring SB-1 the results are shown on Figures 4 and
5. The charts show the first arrival times corrected for the wave source offset. For both borings, the
sledge hammer seismic wave source for the shear wave data is offset about 8.5 feet from the boring,
and the compressional wave source is offset about 4 feet. The times shown are vertical travel times,
and are what the travel times would be if the source was directly on the boring.
Shear Wave Data Results
The shear wave data were recorded using two orientations of the impulse wave created by hitting a
wooden beam at both ends with a sledge hammer. The two shear wave arrival times recorded at each
depth location were usually very similar and most were within 0.5 milliseconds (ms) of each other.
The beam was oriented parallel to one of the sets of vertical grooves in the Slope Indicator casing.
This allows the geophone package to be oriented parallel to the signal orientation which allows for
optimum data quality. The beam was almost perfectly level (horizontal) and in good contact with the
asphalt surface. The quality of the data was generally very good in both holes.
Philip H. Duoos 13503 NE 78th Place, Redmond, Washington, 98052
PH/FAX: (425) 882-2634, CELL: (425) 765-6316 Email: geopyg@aol.com
2
2
Figure 2 shows the shear wave first arrival data and interpreted layers for Boring SB-1. Figure 4
shows the shear wave results for Boring SB-2. The interpreted layers and velocities are indicated by
the best-fit lines. The lines alternate color (blue and green) to help differentiate between the layers.
The shear wave data in both borings are fairly linear and were straightforward in their interpretation.
These results were based primarily on the data and the geologic logs were reviewed afterward and
correlate well with the original interpretation. On Boring SB-2 I did revise my initial interpretation of the
deepest layer in an attempt to get the top of the last layer closer to the approximate top of rock
(Renton Formation Sandstone). The results also correlate well between the two borings with the
various sequence of layers and their velocities.
Compressional Wave Data Results
Figure 3 shows the compressional wave data for Boring SB-1, and the results for Boring SB-2 are
provided on Figure 5. The compressional wave data is less detailed than the shear wave data, both
due to the geologic factors and the larger sampling interval of 5 feet. The velocity layer interpretation
is indicated by the alternating red and orange lines. The presence of ground water (at about 5 feet
deep at the site) greatly affects the compressional wave data, but has no impact on the shear wave
data.
In Boring SB-2 I have interpreted a thin low velocity layer above the last velocity layer (Renton
Formation). This thin layer (velocity of 3,050 fps) is questionable due to the lack of data (Figure 5)
within this layer, and is based more on the geologic log than the seismic data. Inserting the thin layer
puts the higher velocity layer of 4,400 fps near the top of rock observed in the boring. However, this
thin layer does seem to correlate with the lower blow counts from about 50 to 63 feet deep, with some
organics observed at 55 feet deep.
The interpreted compressional wave velocity (4,400 fps) of the rock is on the low end of seismic
velocities for competent Renton Formation sandstone. I have observed velocities as low as 4,350 fps
for competent Renton Formation sandstone, but more often it is in the range of 8,000 to 11,000 fps. I
suspect that the wide range of velocities is related to the degree of fracturing and/or cementation of
the rock. The velocity of 4,400 fps may also indicate a degree of weathering near the rock surface as
we were only able to measure velocities in the upper 10 feet of the rock layer in Boring SB-2. Both
shear wave and compressional wave data were obtained at 2-foot intervals in the rock layer in an
attempt to get accurate velocity measurements within the unit.
The 6,780 fps velocity layer is reasonable for the water-saturated sand and gravel unit observed in
Boring SB-2. In Boring SB-1 this layer has a slightly lower velocity of 6,175 fps which may be due to
more sand than gravel in Boring SB-1.
FIELD METHODOLOGY
The first-arrival travel times were measured using a triaxial geophone located at 2.5-foot (shear wave)
and 5-foot (compressional wave) increments in the boring; and are referenced to the ground surface.
The shear wave energy was generated by hitting both ends of a wood beam (with steel end caps)
placed on the ground surface a distance of about 8.5 feet from each boring. Hitting the beam on both
ends, and recording both of the orientations of the impulse wave, helps to identify the shear wave and
also provides an idea on the quality of the data.
The borehole casing was standard Slope Indicator casing (2.75-inch inside diameter) with vertical
grooves which allowed us to maintain a constant orientation with the downhole geophone tool. The
boring was bailed dry to about 40 feet which allowed for easier data acquisition and minimized the
possibility of seismic surface waves traveling down the borehole.
The beam was placed parallel to one set of the grooves of the casing. The front wheels of a vehicle
were then driven up onto the beam and parked so that the beam would maintain firm contact with the
ground. The asphalt surface was smooth, and good contact between the beam and the asphalt was
obtained with minimal movement of the beam as it was hit with the sledge hammer.
3
3
After the shear wave data were obtained, the beam was removed and compressional data were
recorded. The compressional wave was generated by hitting a steel plate that was placed on asphalt
surface about 4 feet from each boring. The triaxial geophone was then placed in the boring again, and
compressional wave data were recorded at 5-foot intervals, with the metal plate struck vertically with
the sledge hammer.
The seismic data were recorded using a Geostuff Instruments BHG-2 triaxial geophone and a
Geometrics Strataview seismograph. The seismograph allows the stacking of multiple hits with the
sledge hammer where the signal will increase with each blow, while the random noise tends to reduce.
The BHG-2 downhole geophone obtains firm coupling with the borehole using a mechanical clamping
spring arm.
I am confident that the recorded data and interpreted velocities and layer depths are representative of
the subsurface materials at the boring location within the constraints of this geophysical method. The
interpreted velocities are within the typical ranges for the types of materials described in the geologic
logs, and which I have observed at other sites in the Pacific Northwest region. As with any
geophysical method, bulk properties are measured and may not discern small variations in geology.
Review of these results by a geologist familiar with the site conditions is also recommended.
Please feel free to contact me if you have any questions or comments regarding this information.
Sincerely,
Philip H. Duoos
Geophysical Consultant
Washington State Licensed Geologist No. 561
Attachments:
Table 1: Layer Velocity Summary Table
Figure 1: Borehole Location Map
Figure 2: Boring SB-1 Shear Wave Results Graph
Figure 3: Boring SB-1 Compressional Wave Results Graph
Figure 4: Boring SB-2 Shear Wave Results Graph
Figure 5: Boring SB-2 Compressional Wave Results Graph
Table 1
SHEAR AND COMPRESSIONAL WAVE VELOCITIES
Borings SB-1 and SB-2
I-405 Bus Rapid Transit Facility
Renton, Washington
For WSP USA Inc.
WSP # 16036P3
Shear Wave Velocities (ft/sec)
Depth Range (ft) Velocity (ft/sec)
0 - 7.5 650
7.5 - 37.0 390
37.0 - 56.0 725
56.0 - 72.0 1,605
72.0 - 77.0 525
77.0 - 104.0 1,505
Shear Wave Velocities (ft/sec)
Depth Range (ft) Velocity (ft/sec)
0 - 4.5 1,010
4.5 - 24.0 380
24.0 - 39.0 765
39.0 - 49.0 1,055
49.0 - 61.5 640
61.5 - 69.0 1,910
Compressional Wave Velocities (ft/sec)
Depth Range (ft) Velocity (ft/sec)
0 - 8.0 1,350
8.0 - 41.5 2,310
41.5 - 104.0 6,175
Compressional Wave Velocities (ft/sec)
Depth Range (ft) Velocity (ft/sec)
0 - 11.0 1,395
11.0 - 27.0 2,685
27.0 - 58.5 6,780
57.0 - 62.0 3,050 ?*
62.0 - 69.0 4,400
*Thin layer with velocity of 3,050 is questionable due
to lack of data within the thin layer. While it fits the
seismic data, it is based more on the geologic log.
Boring SB-1
Boring SB-2
Philip H. Duoos, Geophysical Consultant
for WSP USA Inc., WSP #160363P
PHD # 1363-21, Sept. 13, 2021
TABLE 1
Shear and Compressional Wave Velocities
Borings SB-1 and SB-2
I-405 Bus Rapid Transit Facility
200 ft
N➤➤N
200'
N
SITE LOCATION MAP
Downhole Shear Wave Study
I-405 BRT and Bus Operations & Maintenance Facility
Renton, Washington
WSP Project # 160363P3
P. Duoos, Geophysical Consultant
PHD # 1363-21, Sept 13, 2021 Fig. 1
-110
-105
-100
-95
-90
-85
-80
-75
-70
-65
-60
-55
-50
-45
-40
-35
-30
-25
-20
-15
-10
-5
0
0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160Depth Below Surface ( feet )Travel Time ( ms )
Shear Wave Vertical Travel Time, Boring SB-1
Philip H. Duoos, Geophysical Consultantfor WSP USA Inc. WSP Project #160363P3
PHD #1363-21, Aug. 19, 2021
BORING SB-1
SHEAR WAVE FIRST ARRIVAL TIMES
Interpreted Layer Velocity Intervals
I-405 Bus Rapid Transit Facility
Renton, Washington
650 fps
1,605 fps
725 fps
525 fps
7.5'
37'
72'
56'
77'
1,505 fps
390 fps
Boring SB-1 is located near the NE corner of the
existing building and completed to a depth of 105'.
Fig. 2 Sept. 13, 2021
-105
-100
-95
-90
-85
-80
-75
-70
-65
-60
-55
-50
-45
-40
-35
-30
-25
-20
-15
-10
-5
0
0 10 20 30 40Depth Below Surface (feet)Travel Time (ms)
Compressional Wave Vertical Travel Time, Boring SB-1
2,310 fps
8'
6400 SE 101st Industrial
Portland, Oregon
for Terra Associates, Inc., PN T-8251
FIGURE 1
41.5'
?
June 7, 2020
1,350 fps
6,175 fps
Philip H. Duoos, Geophysical Consultant
for WSP USA Inc. WSP Project #160363P3
PHD #1363-21, Aug. 19, 2021
BORING SB-1
COMPRESSIONAL WAVE FIRST ARRIVAL TIMES
Interpreted Layer Velocity Intervals
I-405 Bus Rapid Transit Facility
Renton, Washington
Boring SB-1 is located near the NE corner of the
existing building and completed to a depth of 105'.
Fig. 3 Sept. 13, 2021
-80
-75
-70
-65
-60
-55
-50
-45
-40
-35
-30
-25
-20
-15
-10
-5
0
0 10 20 30 40 50 60 70 80 90 100 110 120Depth Below Surface ( feet )Travel Time ( ms )
Shear Wave Vertical Travel Time, Boring SB-2
1,010 fps
380 fps
1,055 fps
4.5'
24'
49'
39'
61.5'
1,910 fps
Philip H. Duoos, Geophysical Consultant
for WSP USA Inc. WSP Project #160363P3
PHD #1363-21, Aug. 19, 2021
BORING SB-2
SHEAR WAVE FIRST ARRIVAL TIMES
Interpreted Layer Velocity Intervals
I-405 Bus Rapid Transit Facility
Renton, Washington
Boring SB-2 is located near the SW corner of the
existing building and completed to a depth of 70'.
765 fps
640 fps
Fig. 4 Sept. 13, 2021
-80
-75
-70
-65
-60
-55
-50
-45
-40
-35
-30
-25
-20
-15
-10
-5
0
0 10 20 30 40Depth Below Surface ( feet )Travel Time ( ms )
Compressional Wave Vertical Travel Time, Boring SB-2
1,395 fps
2,685 fps
4,400 fps
11'
62'
6,780 fps
27'
Philip H. Duoos, Geophysical Consultant
for WSP USA Inc. WSP Project #160363P3
PHD #1363-21, Aug. 19, 2021
BORING SB-2
COMPRESSIONAL WAVE FIRST ARRIVAL TIMES
Interpreted Layer Velocity Intervals
I-405 Bus Rapid Transit Facility
Renton, Washington
Boring SB-2 is located near the SW corner of the
existing building and completed to a depth of 70'.
57'
3,050 fps ??
Questionable thin velocity layer to
correlate 4,400 fps layer closer to
top of rock observed in geologic log
(at approximately 63 feet deep)
Fig. 5 Sept. 13, 2021
AE 0054-17 | South Renton Transit Center Geotechnical
Recommendation Report
I-405 corridor
Laboratory Test Results
RW-10 S-3 7.5 9.0 63.7 50 29 21 89.3 MH Gray, elastic SILT
RW-10 S-5 13.0 14.0 163.8 OL Very dark grayish-brown, organic SILT
RW-10 S-9a 30.5 31.0 62.0 55.9 ML Very dark grayish-brown, SILT with organics
RW-10 S-9b 31.0 31.5 61.3 54.9 ML Dark grayish-brown, SILT with organics
RW-11 S-4 10.0 11.5 170.1 OL Dark olive-brown, organic SILT
RW-11 S-6 15.0 17.0 191.4 PT Very dark brown, PEAT
RW-11 S-8 25.0 26.5 38.6 42 29 13 88.6 ML Grayish-brown, SILT
RW-12 S-3 10.0 11.5 38.7 29.5 SM Grayish-brown, silty SAND
RW-12 S-9 35.0 36.5 80.9 111 71 40 18.2 81.8 OH Grayish-brown, organic SILT with sand
RW-12 S-11b 45.2 46.5 37.5 12.2 81.3 6.5 SP-SM Dark gray, poorly graded SAND with silt
SB-1 S-6 12.5 14.5 40.0 36 27 9 74.5 ML Gray, SILT with sand
SB-1 S-9 25.0 26.5 134.4 92 63 29 62.3 OH Olive-brown, sandy organic SILT
SB-1 S-11 36.5 37.5 25.7 95.8 SM Gray, silty SAND
SB-1 S-17 65.0 66.5 7.5 52.6 41.3 6.1 GW-GM Olive-brown, well-graded GRAVEL with silt and sand
SB-2 S-4 10.0 11.5 52.1 46 29 17 97.1 ML Grayish-brown, SILT
SB-2 S-7b 21.0 21.5 57.3 51 37 14 MH Olive-brown, elastic SILT
SB-2 S-12 35.0 36.5 8.7 57.4 36.3 6.2 GW-GM Grayish-brown, well-graded GRAVEL with silt and sand
SB-2 S-14 55.0 56.5 28.4 44.4 SM Dark gray, silty SAND
SH-4 S-4a 11.0 11.5 36.8 SM Olive-brown, silty SAND
SH-4 S-4 15.0 17.0 223.5 PT Very dark brown, PEATEXPLORATIONDESIGNATION
1. This table summarizes information presented elsewhere in the report and should be used in conjunction with the report test, other graphs and tables, and the exploration logs.
2. The soil classifications in this table are based on ASTM D2487 and D2488 as applicable.
MATERIAL PROPERTIES
1
PAGE: 1 of 2
SUMMARY OF
LL CLASSIFICATIONLIMITS (%)
ATTERBERG
CONTENT (%)% SAND% GRAVELPIPL(feet)TOP DEPTHBOTTOM DEPTH(feet)SAMPLE DESCRIPTIONDRY DENSITY (pcf)Notes:ASTM SOILMOISTURECONTENT (%)ORGANIC% FINES2017-135 T3PROJECT NO.:
JHMATSUM 2017-135 PH 3.GPJ 8/19/21
FIGURE:
Laboratory Testing for WSP
I-405 BRT Project - Phase 3
Client Project No.: 160363P3.003 Task 3.04.2
SH-4 S-7 20.0 21.5 73.3 64 43 21 90.2 OH Very dark brown, organic SILT
SH-4 S-9 30.0 31.5 115.2 19.2 PT Dark grayish-brown, PEAT
SH-5 S-3 7.5 9.0 49.6 36 30 6 75.0 ML Grayish-brown, SILT with sand
SH-5 S-4 10.0 11.5 106.5 15.5 OL Grayish-brown, organic SILT
SH-5 S-8 25.0 26.5 62.7 58 53 5 84.9 OH Dark grayish-brown, organic SILT with sandEXPLORATIONDESIGNATION
1. This table summarizes information presented elsewhere in the report and should be used in conjunction with the report test, other graphs and tables, and the exploration logs.
2. The soil classifications in this table are based on ASTM D2487 and D2488 as applicable.
MATERIAL PROPERTIES
2
PAGE: 2 of 2
SUMMARY OF
LL CLASSIFICATIONLIMITS (%)
ATTERBERG
CONTENT (%)% SAND% GRAVELPIPL(feet)TOP DEPTHBOTTOM DEPTH(feet)SAMPLE DESCRIPTIONDRY DENSITY (pcf)Notes:ASTM SOILMOISTURECONTENT (%)ORGANIC% FINES2017-135 T3PROJECT NO.:
JHMATSUM 2017-135 PH 3.GPJ 8/19/21
FIGURE:
Laboratory Testing for WSP
I-405 BRT Project - Phase 3
Client Project No.: 160363P3.003 Task 3.04.2
0
10
20
30
40
50
60
70
80
90
100
0.0010.010.1110
GRAIN SIZE IN MILLIMETERS
50
SAMPLE
S-3
S-8
S-3
7.5 - 9.0
25.0 - 26.5
10.0 - 11.5
50
42
#10
30
CLASSIFICATION OF SOIL- ASTM D2487 Group Symbol and Name
U.S. STANDARD SIEVE SIZES
SAND
3
21
13
Coarse
#60#40#20
Fine Coarse
SYMBOL
Gravel%
3"1-1/2"PERCENT FINER BY WEIGHT#4 #200
Sand%
(MH) Gray, elastic SILT
(ML) Grayish-brown, SILT
(SM) Grayish-brown, silty SAND
Fines%
0.00050.005
CLAY
RW-10
RW-11
RW-12
29
29
SILT
3/4"
GRAVEL
0.05
5/8"
70
#100
0.5
64
39
39
50
Medium Fine
3/8"
5
PI
90
10
% MC LL PLDEPTH ( ft.)
PARTICLE-SIZE ANALYSIS
OF SOILS
METHOD ASTM D6913
89.3
88.6
29.5
2017-135 T3PROJECT NO.:
HWAGRSZ 2017-135 PH 3.GPJ 8/19/21
FIGURE:
Laboratory Testing for WSP
I-405 BRT Project - Phase 3
Client Project No.: 160363P3.003 Task 3.04.2
0
10
20
30
40
50
60
70
80
90
100
0.0010.010.1110
CLAYSILT
3/4"
Medium
GRAIN SIZE IN MILLIMETERS
50
SAMPLE
71
27
40
9
PI Gravel%
12.2
Sand%
18.2
81.3
76.6
90
10
PARTICLE-SIZE ANALYSIS
OF SOILS
METHOD ASTM D6913
% MC
81
38
40
35.0 - 36.5
45.2 - 46.5
12.5 - 14.5
S-9
S-11b
S-6
RW-12
RW-12
SB-1
111
36
Fine Coarse
SYMBOL
3" 1-1/2"
Fines%PERCENT FINER BY WEIGHT#4 #200
(OH) Grayish-brown, organic SILT with sand
(SP-SM) Dark gray, poorly graded SAND with silt
(ML) Gray, SILT with sand
0.00050.005
Clay%LL PL
GRAVEL
0.05
5/8"
70
#100
0.5
Silt%
5.2
#10
30
U.S. STANDARD SIEVE SIZES
SAND
4
Coarse
#60#40
ASTM SOIL CLASSIFICATION
#20
Fine
3/8"
5
6.5
74.5
50
DEPTH ( ft.)
2017-135 T3PROJECT NO.:
HWAGRSZ SILT-CLAY PERCENTAGE 2017-135 PH 3.GPJ 8/19/21
FIGURE:
Laboratory Testing for WSP
I-405 BRT Project - Phase 3
Client Project No.: 160363P3.003 Task 3.04.2
0
10
20
30
40
50
60
70
80
90
100
0.0010.010.1110
GRAIN SIZE IN MILLIMETERS
50
SAMPLE
S-9
S-17
S-4
25.0 - 26.5
65.0 - 66.5
10.0 - 11.5
92
46
#10
41.3
30
CLASSIFICATION OF SOIL- ASTM D2487 Group Symbol and Name
U.S. STANDARD SIEVE SIZES
SAND
5
29
17
Coarse
#60#40#20
Fine Coarse
SYMBOL
Gravel%
3"1-1/2"PERCENT FINER BY WEIGHT#4 #200
52.6
Sand%
(OH) Olive-brown, sandy organic SILT
(GW-GM) Olive-brown, well-graded GRAVEL with silt and sand
(ML) Grayish-brown, SILT
Fines%
0.00050.005
CLAY
SB-1
SB-1
SB-2
63
29
SILT
3/4"
GRAVEL
0.05
5/8"
70
#100
0.5
134
7
52
50
Medium Fine
3/8"
5
PI
90
10
% MC LL PLDEPTH ( ft.)
PARTICLE-SIZE ANALYSIS
OF SOILS
METHOD ASTM D6913
62.3
6.1
97.1
2017-135 T3PROJECT NO.:
HWAGRSZ 2017-135 PH 3.GPJ 8/19/21
FIGURE:
Laboratory Testing for WSP
I-405 BRT Project - Phase 3
Client Project No.: 160363P3.003 Task 3.04.2
0
10
20
30
40
50
60
70
80
90
100
0.0010.010.1110
GRAIN SIZE IN MILLIMETERS
50
SAMPLE
S-12
S-14
S-7
35.0 - 36.5
55.0 - 56.5
20.0 - 21.5 64
#10
36.3
30
CLASSIFICATION OF SOIL- ASTM D2487 Group Symbol and Name
U.S. STANDARD SIEVE SIZES
SAND
6
21
Coarse
#60#40#20
Fine Coarse
SYMBOL
Gravel%
3"1-1/2"PERCENT FINER BY WEIGHT#4 #200
57.4
Sand%
(GW-GM) Grayish-brown, well-graded GRAVEL with silt and sand
(SM) Dark gray, silty SAND
(OH) Very dark brown, organic SILT
Fines%
0.00050.005
CLAY
SB-2
SB-2
SH-4 43
SILT
3/4"
GRAVEL
0.05
5/8"
70
#100
0.5
9
28
73
50
Medium Fine
3/8"
5
PI
90
10
% MC LL PLDEPTH ( ft.)
PARTICLE-SIZE ANALYSIS
OF SOILS
METHOD ASTM D6913
6.2
44.4
90.2
2017-135 T3PROJECT NO.:
HWAGRSZ 2017-135 PH 3.GPJ 8/19/21
FIGURE:
Laboratory Testing for WSP
I-405 BRT Project - Phase 3
Client Project No.: 160363P3.003 Task 3.04.2
0
10
20
30
40
50
60
70
80
90
100
0.0010.010.1110
GRAIN SIZE IN MILLIMETERS
50
SAMPLE
S-3
S-8
7.5 - 9.0
25.0 - 26.5
36
58
#10
30
CLASSIFICATION OF SOIL- ASTM D2487 Group Symbol and Name
U.S. STANDARD SIEVE SIZES
SAND
7
6
5
Coarse
#60#40#20
Fine Coarse
SYMBOL
Gravel%
3"1-1/2"PERCENT FINER BY WEIGHT#4 #200
Sand%
(ML) Grayish-brown, SILT with sand
(OH) Dark grayish-brown, organic SILT with sand
Fines%
0.00050.005
CLAY
SH-5
SH-5
30
53
SILT
3/4"
GRAVEL
0.05
5/8"
70
#100
0.5
50
63
50
Medium Fine
3/8"
5
PI
90
10
% MC LL PLDEPTH ( ft.)
PARTICLE-SIZE ANALYSIS
OF SOILS
METHOD ASTM D6913
75.0
84.9
2017-135 T3PROJECT NO.:
HWAGRSZ 2017-135 PH 3.GPJ 8/19/21
FIGURE:
Laboratory Testing for WSP
I-405 BRT Project - Phase 3
Client Project No.: 160363P3.003 Task 3.04.2
0
10
20
30
40
50
60
70
80
90
100
0 40 80 120 160 200
7.5 - 9.0
25.0 - 26.5
35.0 - 36.5
12.5 - 14.5
25.0 - 26.5
10.0 - 11.5
(MH) Gray, elastic SILT
(ML) Grayish-brown, SILT
(OH) Grayish-brown, organic SILT with sand
(ML) Gray, SILT with sand
(OH) Olive-brown, sandy organic SILT
(ML) Grayish-brown, SILT
LIQUID LIMIT (LL)
50
42
111
36
92
46
% MC LL
RW-10
RW-11
RW-12
SB-1
SB-1
SB-2
64
39
81
40
134
52
LIQUID LIMIT, PLASTIC LIMIT AND
PLASTICITY INDEX OF SOILS
METHOD ASTM D4318
89.3
88.6
81.8
74.5
62.3
97.1
8
21
13
40
9
29
17
CL-ML
% FinesSAMPLE
ML
CLASSIFICATION
MHPLASTICITY INDEX (PI)SYMBOL PL PI
29
29
71
27
63
29
S-3
S-8
S-9
S-6
S-9
S-4
DEPTH (ft)
CL CH
2017-135 T3PROJECT NO.:
HWAATTB EXPANDED SAMPLE COLUMN (HIGH LL) 2017-135 PH 3.GPJ 8/19/21
FIGURE:
Laboratory Testing for WSP
I-405 BRT Project - Phase 3
Client Project No.: 160363P3.003 Task 3.04.2
0
10
20
30
40
50
60
70
80
90
100
0 40 80 120 160 200
21.0 - 21.5
20.0 - 21.5
7.5 - 9.0
25.0 - 26.5
(MH) Olive-brown, elastic SILT
(OH) Very dark brown, organic SILT
(ML) Grayish-brown, SILT with sand
(OH) Dark grayish-brown, organic SILT with sand
LIQUID LIMIT (LL)
51
64
36
58
% MC LL
SB-2
SH-4
SH-5
SH-5
57
73
50
63
LIQUID LIMIT, PLASTIC LIMIT AND
PLASTICITY INDEX OF SOILS
METHOD ASTM D4318
90.2
75.0
84.9
9
14
21
6
5
CL-ML
% FinesSAMPLE
ML
CLASSIFICATION
MHPLASTICITY INDEX (PI)SYMBOL PL PI
37
43
30
53
S-7b
S-7
S-3
S-8
DEPTH (ft)
CL CH
2017-135 T3PROJECT NO.:
HWAATTB EXPANDED SAMPLE COLUMN (HIGH LL) 2017-135 PH 3.GPJ 8/19/21
FIGURE:
Laboratory Testing for WSP
I-405 BRT Project - Phase 3
Client Project No.: 160363P3.003 Task 3.04.2
I-405 BRT - Phase 3 Lab Ttesting
SB-1 Sample No.:S-11 35.0-36.5Soil Description:SILT with sand
Soil Color:Gray Average Strain Rate:0.5 % per min.Soil Group Symbol:ML Soil Specific Gravity:2.65 (assumed)
Normal Stress (psf)1750.00 3500.00 7000.00 AveragePeak Stress (psf)1106.65 2249.79 4335.24
Initial Moisture Content (%):42.6 42.6 42.6 42.6 Cohesion phi Angle
Wet Unit Weight (pcf):104.9 109.3 109.4 107.9 psf (degrees)Dry Unit Weight (pcf):73.6 76.6 76.8 75.6 Peak 63.9 31.5
Calculated Void Ratio 1.248 1.158 1.154 1.187Calculated Porosity 0.555 0.537 0.536 0.543
Calculated Saturation (%)90.4 97.5 97.8 95.2Final Moisture Content (%)48.9 41.1 39.2 43.1
Checked By:S. Greene Figure 10
Indicated Strength Parameters
HWA GEOSCIENCES INC. Materials Testing LaboratoryDirect Shear Test of Soils Under Consolidated Drained Conditions (ASTM D 3080)
2017-135 Phase 3
Sample Point:
Project Name:Project Number:
Sample Depth:
0.00
500.00
1000.00
1500.00
2000.00
2500.00
3000.00
3500.00
4000.00
4500.00
5000.00
0.00 1000.00 2000.00 3000.00 4000.00 5000.00 6000.00 7000.00 8000.00Shear Stress (psf)Normal Stress (psf)
Peak Peak Trend
0.00
500.00
1000.00
1500.00
2000.00
2500.00
3000.00
3500.00
4000.00
4500.00
5000.00
0.00 2.00 4.00 6.00 8.00 10.00 12.00 14.00 16.00 18.00Shear Stress (psf)% Strain
Normal Stress: 1750.00 Normal Stress: 3500.0 Normal Stress: 7000.0
-0.100
-0.080-0.060
-0.040-0.020
0.0000.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0 16.0 18.0
Dilation/Contraction(inches)
Tested By: GB Checked By: SEG
CONSOLIDATION TEST REPORT
Cv(ft.2/day)0
0.4
0.8
1.2
1.6
2
Applied Pressure - ksf
0.1 1 10Percent Strain70
60
50
40
30
20
10
0
-10
-20
-30
Natural Dry Dens.LL PI Sp. Gr. USCS AASHTO
Initial Void
Saturation Moisture
(pcf) Ratio
110.7 % 191.4 % 25.6 1.905 PT 3.294
Very dark brown, PEAT
2017-135 T3 WSP
I-405 BRT Project - Phase 3
Client Project No.: 160363P3.003 Task 3.04.2
Specific gravity by ASTM D 854
11
MATERIAL DESCRIPTION
Project No. Client:Remarks:
Project:
Source of Sample: RW-11 Depth: 15.0 - 17.0 Sample Number: S-6
Figure
Tested By: GB Checked By: SEG
CONSOLIDATION TEST REPORT
Cv(ft.2/day)0
0.015
0.03
0.045
0.06
0.075
Applied Pressure - ksf
0.1 1 10Percent Strain26
23
20
17
14
11
8
5
2
-1
-4
Natural Dry Dens.LL PI Sp. Gr. USCS AASHTO
Initial Void
Saturation Moisture
(pcf)Ratio
104.9 % 42.3 % 79.9 46 17 2.65 ML 1.069
Grayish-brown, SILT
2017-135 T3 WSP
I-405 BRT Project - Phase 3
Client Project No.: 160363P3.003 Task 3.04.2
Specific gravity assumed
12
MATERIAL DESCRIPTION
Project No. Client:Remarks:
Project:
Source of Sample: SB-2 Depth: 10.0 - 11.5'Sample Number: S-4
Figure
Tested By: GB Checked By: SEG
CONSOLIDATION TEST REPORT
Cv(ft.2/day)0
0.4
0.8
1.2
1.6
2
Applied Pressure - ksf
0.1 1 10Percent Strain80
70
60
50
40
30
20
10
0
-10
-20
Natural Dry Dens.LL PI Sp. Gr. USCS AASHTO
Initial Void
Saturation Moisture
(pcf) Ratio
76.8 % 223.5 % 20.6 1.822 PT 5.301
Very dark brown, PEAT
2017-135 T3 WSP
I-405 BRT Project - Phase 3
Client Project No.: 160363P3.003 Task 3.04.2
Specific gravity by ASTM D 854
13
MATERIAL DESCRIPTION
Project No. Client:Remarks:
Project:
Source of Sample: SH-4 Depth: 15.0 - 17.0'Sample Number: S-6
Figure
AE 0054-17 | South Renton Transit Center Geotechnical
Recommendation Report
I-405 corridor
Pavement Design Data and Calculations
I-405 BRT - SRTC Site - Recommended Pavement Sections
M Cline 2/7/2022
SECTION
NO.ROADWAY DESIGN LIFE
(YEARS)
PAVEMENT
TYPE
REQUIRED
STRUCTURAL
NUMBER
PROVIDED
STRUCTURAL
NUMBER
PCCP
THICKNESS1
(IN)
HMA
THICKNESS2
(IN)
CSCB
THICKNESS3
(IN)
TOTAL
THICKNESS
(IN)
ASSUMED SUBSURFACE
CONDITIONS IN UPPER 5-10 FT4
MEASURED
APPROX. DEPTH
TO GROUND-
WATER (FT)
SUBGRADE PREPARATION NOTES
1 Bus Lane 20 Rigid N/A N/A 11.0 0.0 6.0 17.0 Loose sands and soft, wet silts </=5
Prior to construction of the
pavement section, place
geosynthetics per Note 5.
Recommendation is based on design
analysis.
2 Parking Lot/Garage Access 20 Flexible 3.43 3.54 0.0 5.0 8.0 13.0 Loose sands and soft, wet silts </=5
Prior to construction of the
pavement section, place
geosynthetics per Note 5.
Recommendation is based on design
analysis.
3 Lake Ave S 20 Flexible 6.14 6.17 0.0 10.0 9.0 19.0 Loose sands and soft, wet silts </=5
Prior to construction of the
pavement section, place
geosynthetics per Note 5.
Recommendation is based on design
analysis.
NOTES:
1) WSDOT Item 5-05
2) WSDOT Item 5-04
3) WSDOT Item 4-04
4) Assumed subgrade conditions must be verified prior to construction.
5) Place geogrid (Tencate’s Mirafi BXG, Tensar’s TriAx, or Carthage Mills GBX) over geotextile (WSDOT Item 9-33, Table 3) on existing subgrade in accordance with manufacturer's specifications.
- Analysis and results assume up to 3' cut and 1.5' fill.
I-405 BRT - SRTC Site - ESAL Computations
M Cline 1/12/2022
Initial Service Year (ISY): 2026 Rigid ESAL Factor, Car: 0.0002 Rigid ESAL Factor, Truck: 1.7 Rigid ESAL Factor, 40-ft Single Unit (SU) Bus: 4.42 Rigid ESAL Factor, 60-ft Articulated Bus: 6.4
SECTION
NO.ROADWAY
DESIGN CODE
(FOR DESIGN
LIFE)
DESIGN
LIFE
(YEARS)
PAVEMENT
TYPE,
R OR F1
NO. OF
LANES
GROWTH
RATE, BUS
TRAFFIC2
GROWTH
RATE, GEN.
PURPOSE
TRAFFIC2
ADT3 % TRUCKS % 40-ft SU
BUSSES
% 60-ft
ARTIC.
BUSSES
TOTAL %
BUSSES
%SU/
%TOTAL
BUSSES
% Artic./
%TOTAL
BUSSES
% CARS TOTAL %
VEHICLES
# BUSSES
PER DAY
# TRUCKS
PER DAY
# CARS PER
DAY
GROWTH
FACTOR, BUS
TRAFFIC
GROWTH
FACTOR, GEN.
PURPOSE
TRAFFIC
TOTAL RIGID
18K ESALS (NO
LDF OR DDF)
LDF4 DDF5 FACTORED
RIGID
18K ESALS
DESIGN
LANE
18K ESALS
(R OR F)
1 Bus Lane Sound Transit
(2021)20 R 1 0.0 0.0 1,265 0.0 0.0 100.0 100.0 0.0 100 0.0 100.0 1,265 0 0 20.00 20.00 59,101,400 1.0 1.0 59,101,400 59,101,400
2 Parking Lot/Garage Access Sound Transit
(2021)20 F 1 0.0 0.0 950 3.0 0.0 0.0 0.0 N/A N/A 97.0 100.0 0 28.5 922 20.00 20.00 355,000 1.0 1.0 355,000 236,700
3 Lake Ave S City of Renton
(1998)20 F 1 0.0 1.0 2,550 2.0 0.0 20.0 20.0 0.0 100.0 78.0 100.0 510 51 1,989 20.00 22.02 24,527,400 1.0 1.0 24,527,400 16,351,600
NOTES:
1) R = Rigid, F = Flexible
2) Minimum value must be 0.0001. Do not enter 0.
3) ADT = Average Daily Traffic
4) LDF = Lane Distribution Factor, from AASHTO (1993) to estimate design lane traffic load based on number of lanes
5) DDF = Directional Distribution Factor, from AASHTO (1993) to estimate design lane traffic load based on directional distribution of traffic
COMPUTATIONS (per AASHTO, 1993):
When applicable, used iterative process varying values of % 40-ft busses and % 60-ft busses to obtain the # busses per day (which was provided by the Traffic Engineer)
% Cars = 100.0 - % trucks - % busses
Growth Factor = ((1+Growth Rate/100)^Design Life-1)/(Growth Rate/100)
Total Rigid 18K ESALs = (# SU Busses Per Day * SU Bus ESAL Factor + # Artic. Busses Per Day * Artic. Bus Factor + # Trucks Per Day * Truck ESAL Factor + # Cars Per Day * Car ESAL Factor) * 365 * Growth Factor
Factored Rigid 18K ESALs = Total Rigid 18K ESALs * LDF * DDF
Design Lane 18K ESALs = For rigid pavement, Design Lane 18K ESALs is Factored Rigid 18K ESALs. For flexible pavement, Design Lane 18K ESALs is Factored Rigid 18K ESALs divided by 1.5 (per AASHTO, 1993).
ASSUMPTIONS:
Values of one directional ADT for ISY, % trucks, # busses, distribution of busses, and growth rates were provided by the Traffic Engineer.
ESAL factors were assumed based on discussions with Seattle Dept of Transportation for Alaskan Way Viaduct Project (2017).
Used Design Life of 20 years for Lake Ave to be consistent with other two sections. City of Renton code does not specify design life.
Enter values for cells with blue
I-405 BRT - SRTC Site - Structural Design Inputs/Assumptions for Flexible Pavement Design
M Cline 1/12/2022
SECTION
NO.ROADWAY DESIGN CODE ANALYSIS
METHOD1a,b
DESIGN
LIFE
(YEARS)2
PAVEMENT
TYPE RELIABILITY
INITIAL
SERVICE-
ABILITY
INDEX
FINAL
SERVICE-
ABILITY
INDEX
STANDARD
DEVIATION
SUBSURFACE CONDITIONS IN
UPPER 5-10 FT
MEASURED
APPROX. DEPTH
TO GROUND-
WATER (FT)
FROST
GROUP3
FROST
SUSCEPTIBILITY3
FROST
DEPTH4
(IN.)
ASSUMED
SUBGRADE
RESILIENT
MODULUS5
ELASTIC
MODULUS,
CSBC
(PSI)
LAYER
COEFFICIENT,
HMA
LAYER
COEFFICIENT,
CSBC
1 Parking Lot/Garage Access Sound Transit
(2021)
AASHTO
(1993)20 Flexible 85 4.2 2.0 0.45 Loose sands and soft, wet silts </=5 F3/F4 High to Very High 15 3,300 30,000 0.50 0.13
2 Lake Ave S City of Renton
(1998)
AASHTO
(1993)20 Flexible 85 4.2 2.0 0.45 Loose sands and soft, wet silts </=5 F3/F4 High to Very High 15 3,300 30,000 0.50 0.13
NOTES:
1a) Used AASHTO (1993) design procedures. City of Renton design code (1998) specifies that the Asphalt Institute's Thickness Design Manual (MS-1) is to be used for pavement design. Based on AI's website, the method is based on the AASHTO 1993, 1998 methods. Must be confirmed.
1b) Except where noted below, AASHTO (1993) input parameters were used in the analyses.
2) For Section 1, Design Life based on Sound Transit (2021). Used same for Section 2 since design life is not specified in City of Renton (1998).
3) Frost Group/Susceptibility determined based on FHWA's Geotechnical Aspects of Pavements (2006).
4) Frost Depth obtained from WSDOT (2018), Figure A2.3.
5) Based on correlation with assumed CBR for subgrade soils. Must be confirmed after review of lab test results.
Additional note: Drainage coefficient = 1.0.
I-405 BRT - SRTC - Structural Design Inputs/Assumptions for Rigid Pavement Design
Michelle Cline
1/12/2022
INPUT VALUE REFERENCE
Analysis Method --AASHTO Guide for Design of Pavement Structures (1993, 1998) per WSDOT Pavement Policy (2018)
Initial Service Year 2026 Provided by Traffic Engineer
Design Life 20 years Sound Transit (2021)
ESALs, Bus Lane 59,101,400 Computed in ESALs worksheet
Reliability 85%AASHTO(1993)/WSDOT Pavement Policy (2018) for <10 million ESALs
Initial Serviceability Index 4.5 AASHTO Guide for Design of Pavement Structures (1993)
Terminal Serviceability Index 2.0 AASHTO Guide for Design of Pavement Structures (1993)
Standard Deviation 0.35 AASHTO Guide for Design of Pavement Structures (1993)
Joint Load Transfer Coefficient 3.2 WSDOT Pavement Policy (2018)
Modulus of Rupture 700 psi WSDOT Pavement Policy (2018)
Modulus of Elasticity 4.0E06 psi WSDOT Pavement Policy (2018)
Subgrade Soil/GW Conditions in
Assumed Soil Profile --Loose sands and soft, wet silts; GW </= 5'
References for Subgrade Soil/GW
Conditions --Borings S-1, SB-2, SH-4, SH-5, BH-7 through 10, BH-15
k-value 100 psi per in.Correlations based on soil classification and assumed CBR (Hall, 2001; FHWA, 1997)
Frost Depth 15 in.WSDOT Pavement Policy (2018)
Frost Group/Susceptibility F3/F4 - High to Very
High FHWA Geotechnical Aspects of Pavements (2006)
Base Thickness 6.0 Assigned
Slab/Base Friction Coefficient 2.0 Estimated based on ranges in 1988 AASHTO Supplement
Procedure Worksheet (for slab on aggregate)
Joint Spacing 15 ft WSDOT Pavement Policy (2018)
Edge Support Adjustment Factor 0.94 1988 AASHTO Supplement
Procedure Worksheet for 12' lane and concrete tied shoulder
Concrete Poisson's Ratio 0.2 Typical value (FHWA)
Layer Modulus, CSBC 30K psi WSDOT Pavement Policy (2018)
Mean Annual Temperature 52 deg F LTPP InfoPave online module
Mean Annual Precipitation 35 in.LTPP InfoPave online module
Mean Annual Wind Speed 2 mph LTPP InfoPave online module
Dowel Diameter 1.5 in.WSDOT Pavement Policy (2018)
Drainage Coefficient 1.00 WSDOT Pavement Policy (2018)
Friction Adjustment Factor 0.8 For aggregate base (per Joint Faulting Check Worksheet)
Base Type 0 For unstabilized base (per Joint Faulting Check Worksheet)
Widened Slab 0 For slab that is not widened (per Joint Faulting Check Worksheet)
Annual Temperature Range 69 deg F LTPP InfoPave online module (Avg Max - Avg Min)
Freezing Index 25 F deg-days LTPP InfoPave online module
Days above 90 deg F 0.5 LTPP InfoPave online module
1998 AASHTO Supplement Procedure Worksheet
General Inputs/Material Properties
Joint Faulting Check Worksheet
LTPP INFOPAVE - CLIMATE DATA FOR BELLEVUE, WASHINGTON
https://infopave.fhwa.dot.gov/Data/ClimateTool1/7/2022
MERRA_ID YEAR PRECIPITATION
152733 2010 39.06152733201133.18
152733 2013 30.01152733201239.86
152733 2014 37.24152733201538.29
152733 2016 38.57152733201738.07
152733 2018 31.08152733202035.64
152733 2019 28.12AVERAGE:35.37
MERRA_ID YEAR TEMP_AVG TEMP_MAX TEMP_MIN TEMP_MEAN_AVG TEMP_MEAN_STDEV DAYS_ABOVE_32_C FREEZE_INDEX152733201050.54 88.7 15.98 50.9 32.3384 0 32
152733 2011 48.92 80.42 19.04 49.1 32.2898 0 2715273320125091.04 24.8 50.36 32.4716 1 13
152733 2014 51.98 92.84 14.36 52.52 32.3744 1 49152733201350.54 90.32 13.64 51.08 32.378 1 40
152733 2016 52.16 90.5 22.82 52.7 32.4122 1 23152733201750.54 93.02 20.48 50.9 32.3294 1 48
152733 2019 51.08 89.78 19.58 51.62 32.3132 0 31152733202051.44 91.58 25.52 51.98 32.3618 1 2
152733 2015 53.06 89.6 24.62 53.6 32.234 0 0152733201851.62 88.16 21.74 51.98 32.3654 0 13
AVERAGE:51.08 89.63 20.23 51.52 32.35 0.55 25.27avg temp range:69.40
MERRA_ID YEAR WIND_VELOCITY_AVG15273320112
152733 2010 215273320122
152733 2013 215273320152
152733 2016 215273320192
152733 2014 215273320172
152733 2018 215273320202
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