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GEOTECHNICAL EVALUATION - 30 PERCENT
DESIGN
King County Parks and Recreation Division – Renton Shop
3005 4th Street NE
Renton, Washington
Prepared for: Mr. Christopher Walling, Project Manager
HDR Architecture, Inc.
Project No. 170383 - Task 400 May 31, 2019 DRAFT e a r t h w a t e r+ppeecc tt
C O N S U L T I N G
V:\170383 King County Parks Central Maintenance Facility #E00491E17\Deliverables\Prelim Geotech Report\Renton Shop_GeoRpt_20180320.docx
GEOTECHNICAL EVALUATION - 30 PERCENT DESIGN
King County Parks and Recreation Division – Renton Shop
3005 4th Street NE
Renton, Washington
Prepared for: Mr. Christopher Walling, Project Manager
HDR Architecture, Inc.
Project No. 170383 - Task 400 May 31, 2019 DRAFT
Aspect Consulting, LLC
Mark Swank, LG, LEG
Senior Engineering Geologist
mswank@aspectconsulting.com
Engineering Geology
Henry H. Haselton, PE, PMP
Principal Geotechnical Engineer
hhaselton@aspectconsulting.com
Geotechnical Engineering
John Knutson, PE
Principal Water Resources Engineer
jknutson@aspectconsulting.com
Stormwater Engineering
Preliminary Preliminary
Preliminary
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Contents
1 Introduction ................................................................................................. 1
1.1 General ...................................................................................................... 1
1.2 Scope of Services ..................................................................................... 1
1.3 Project Description ................................................................................... 2
2 Site Conditions ............................................................................................ 4
2.1 Site Description ......................................................................................... 4
2.2 Critical Areas ............................................................................................. 5
2.3 Geologic Setting ....................................................................................... 5
2.3.1 Geology ............................................................................................... 5
2.3.2 Faults and Seismicity .......................................................................... 6
2.3.3 Geologic and Seismic Hazards ........................................................... 6
2.4 Site Reconnaissance ................................................................................. 8
2.5 Subsurface Conditions ............................................................................. 8
2.5.1 Previous Subsurface Explorations ..................................................... 8
2.5.2 Aspect Consulting Subsurface Explorations ..................................... 9
2.5.3 Soil Infiltration Rates ........................................................................ 10
3 Conclusions and Recommendations ....................................................... 13
3.1 General .................................................................................................... 13
3.2 Seismic Design Criteria .......................................................................... 14
3.3 Foundation Design ................................................................................. 14
3.3.1 Shallow Foundations ........................................................................ 14
3.4 Floor Slabs and Modulus of Subgrade Reaction .................................. 15
3.5 Pavement Design .................................................................................... 15
3.6 Stormwater Management Design ......................................................... 16
3.6.1 Steep Slope Setback and Groundwater Considerations ................ 16
3.6.2 Infiltration Test Analyses and Infiltration Gallery Design ............... 17
3.6.3 Water Quality Treatment and Underground Injection Control ....... 19
4 Construction Considerations .................................................................... 20
4.1 General .................................................................................................... 20
4.2 Site Preparation ...................................................................................... 20
4.3 Proofrolling and Subgrade Verification ................................................ 20
4.4 Wet Weather Conditions ........................................................................ 21
4.5 Excavation ............................................................................................... 21
4.5.1 General .............................................................................................. 21
4.5.2 Trenches ............................................................................................ 21
4.5.3 Temporary and Permanent Slopes .................................................. 22
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4.6 Structural Fill Materials and Compaction ............................................. 22
4.7 Ground Moisture .................................................................................... 24
4.7.1 General .............................................................................................. 24
4.7.2 Perimeter Footing Drains ................................................................. 24
4.8 Construction-Phase Stormwater Considerations ................................. 24
4.8.1 Protection and Verification of Infiltration Receptor Soils ............... 24
4.8.2 Geotextiles for Stormwater Drainage .............................................. 25
5 Project Design and Construction Monitoring .......................................... 26
6 References .................................................................................................. 27
7 Limitations ................................................................................................. 29
List of Tables
Table 1. Summary of Site Conditions ................................................................4
Table 2. Geologic and Seismic Hazards Potentially Affecting the Site ............7
Table 3. Field Infiltration Test Results.. ............................................................ 11
Table 4. 2018 IBC Seismic Design Parameters.. .............................................. 14
Table 5. Spread Footing Foundation Design Recommendationsa.. .............. 15
Table 6. Preliminary Pavement Section… ....................................................... 16
Table 7. Infiltration Analyses Results and Design Parametersa..................... 18
Table 8. Fill Type and Compaction Requirements… ....................................... 23
List of Figures
1 Site Location Map
2 Site and Exploration Plan
3 Critical Areas Map
List of Appendices
A Aspect Soil Exploration Logs
B Vibrating Wire Piezometers Hydrograph
C Laboratory Test Results
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D Stormwater Infiltration Analyses
E King County May 22, 2017 Preliminary Geotechnical Design Report –
Subsurface Explorations
F Report Limitations and Guidance for Use
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1 Introduction
1.1 General
This report summarizes Aspect Consulting, LLC’s (Aspect) Geotechnical Evaluation –
30 Percent Design for the King County (County) Parks and Recreation Division’s
(Parks’) Renton Shop located at 3005 4th Street NE in Renton, Washington (Site). We
performed our services in accordance with our agreed-upon scope of work and signed
contract dated January 18, 2018 and additional contract amendments. The Site location is
shown on Figure 1, Site Location Map.
This report presents the following sections:
1. Introduction – describing scope of services and the project
2. Site Conditions – describing critical areas, geologic setting, site reconnaissance,
and subsurface conditions
3. Conclusion and Recommendations – summarizing design recommendations for
seismic, foundation, floor slabs, pavement design, and stormwater management
4. Construction Considerations – general recommendations for Site prep,
proofrolling, working in wet weather conditions, excavation, structural fill,
ground moisture, and construction-phase stormwater considerations
5. Project Design and Construction Monitoring
Appendices A-F, including:
Appendix A - Aspect Soil Exploration Logs
Appendix B - Vibrating Wire Piezometers Hydrograph
Appendix C - Laboratory Test Results
Appendix D - Stormwater Infiltration Analyses
Appendix E - King County May 22, 2017 Preliminary Geotechnical Design
Report – Subsurface Explorations
Appendix F -Report Limitations and Guidance for Use
1.2 Scope of Services
Our scope of services included a literature review, Site reconnaissance, geotechnical and
environmental subsurface explorations, stormwater infiltration evaluations, laboratory
testing, and critical areas and geotechnical engineering assessments of the Site. This
report includes:
Site and 30 percent design project descriptions
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A discussion of the data review findings, including opinions regarding the effects
of relevant geologic and seismic hazards and possible past Site activities on
future development
Distribution and characteristics of the shallow subsurface soils and groundwater
conditions (explorations shown on Figure 2, Site Exploration Map)
Geotechnical and environmental exploration logs and a Site plan showing
approximate exploration locations
Deep infiltration well installations, testing, and analyses
Geotechnical and environmental laboratory test results
An assessment of relevant critical area (geohazard and aquifer protection)
considerations, and preliminary recommendations for seismic design, earthwork,
shoring, foundation support, slabs-on-grade support, retaining walls, stormwater
infiltration, pavement design, and related geotechnical construction
recommendations
Review of the alternatives and the geotechnical feasibility, risk factor and cost
input
Translating requirements from the County’s preliminary geotechnical report
which references WSDOT specifications into CSI based language per King
County specifications
1.3 Project Description
The Renton Shop Facility plays a critical role in Parks’ ability to adequately and
efficiently serve the regional trails, back country trails, and parks throughout the County.
This facility functions as the headquarters for Parks’ Operations & Maintenance (O&M)
Section and acts as the dispatch center for the centralized work crews supporting the
entire system. The Site consists of several small facilities, parking areas, and yard storage
areas, providing work space for the O&M staff, warehousing/inventory, and Parks’
emergency operations center.
The Renton Shop Facility Design (Project) will design and construct facilities large
enough to accommodate future growth of Parks’ O&M Section. Preliminary designs,
feasibility analyses, and preliminary permit application processes were completed with
the City of Renton (City) based upon the previous anticipated needs from 2009 to 2014.
Site redevelopment, new utilities, and new facilities are necessary to accommodate the
current and future operations and the work space for employees over the next 25 to 30
years. The Project is intended to create a functionally efficient Site, with a combined
40,000 to 60,000 square feet (sq2) of total enclosed facilities. Proposed facilities include:
• Building CA is the main building along the south property line and will contain
crew work spaces, locker rooms, restrooms, workshop areas, offices, storage,
training/conference rooms, and accessory support spaces. The building is shown
as a two-story structure with high and low roof lines and a glass mezzanine.
• Building SH is a large, single-level shop building in the center of the Site that
also includes covered parking for equipment adjacent on its west side. The
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structure has a large open area for maintenance work and a high roof with roll-up
gates.
• Building ST is a combined covered materials storage and parking area along the
west property line.
• Uncovered material storage bins and parking areas are planned along the property
boundaries and surrounding the buildings.
• Below-ground stormwater facilities identified on Figure 2 as the West Side
Stormwater Management Facility and East Side Stormwater Management Facility
will manage on-site stormwater with a series of trenches discharging into the
receptor soil at 10 to 15 below the existing ground surface (bgs).
Per King County’s 2015 Strategic Climate Action Plan 1 and the most current adopted
Green Building and Sustainable Development Ordinance #17709, the Project must be
designed and constructed to meet the requirements of LEED™ Platinum certification by
the United States Green Building Council (USGBC) as a base requirement. The Project
may additionally achieve design to achieve Net Zero certification or Petal certification by
the International Living Future Institute – if the County decides to pursue this
certification.
1 https://www.kingcounty.gov/services/environment/climate/strategies/strategic-climate-action-plan.aspx
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2 Site Conditions
2.1 Site Description
Site details are provided in Table 1 below.
Table 1. Summary of Site Conditions
Detail Description
Location Parcel 143400-0012 with a legal Site address listed as 3003 4th Street NE,
Renton, Washington
Existing conditions
The roughly rectangular 5.71-acre Site is currently the County’s active
Central Maintenance Facility. Three buildings consisting of offices and
maintenance garages are situated in the western portion of the property
and the eastern portion is primarily open lots paved with asphalt or gravel.
A driveway traverses east-west through the middle of the Site and a small
building is on the located on the south side of it, near the center of the
property.
Current ground cover
The Site is primarily open, paved and unpaved lots. Limited landscaping is
planted near the front of one of the Site buildings and consists of a few
deciduous trees, plants, and small shrubs. The perimeter of the Site on the
north, west, and south sides consists of larger deciduous type trees, weeds,
and shrubs.
Site topography
The ground surface is relatively flat with elevation (EL, NAVD88) between
approximately EL 325 feet and EL 330 feet, sloping gradually down to the
west. Steeper slopes are along the western and north-western property
boundaries.
Adjacent Properties
The Site is bounded, for a distance of 150 feet beyond the Site’s perimeter
and proposed easement, by:
North Side: Renton Housing Authority Residential Property (Parcel
1623059120), AM PM Convenience Store and Gas Station (Parcel
1623059115) and the currently vacant King County Public Health Offices
(Parcel 1623059130).
East Side: An asphalt paved access road (Parcel 1434000010) for other
King County facilities in the area is directly adjacent to the planned DNRP
Maintenance Facility. In addition, there is an approximate 50-foot-deep
depression that was previously used to mine sand and gravel (Parcel
1623059059).
South Side: County property (Parcel 1434000020) that includes a gravel
surfaced equipment storage area and other undeveloped property with
natural vegetation.
West Side: Commercial properties (Parcels 1623059144 and 1623059143)
that include office and storage facilities. The City of Renton has issued a
preliminary building permit for Parcel 1623059144 to remove an existing
building and add a new three-story building totaling approximately 58,350
square feet.
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2.2 Critical Areas
The City of Renton's Maps (COR; City of Renton, 2018), an online GIS portal, was
reviewed for potential Critical Areas at the Site that consider aquifer protection area
zones, coalmines, erosion hazards, flood zones, landslides, regulated slopes and
shorelines, wetlands, and seismic hazards. Specific geologic hazards identified in the
Renton Municipal Code (RMC) Section 4-3-050 include Steep Slopes, Landslides,
Erosion, Seismic and Coal Mines.
Based on the COR data, the Critical Areas are shown on Figure 3, Critical Areas Map and
include:
• The Site and surrounding area is within the Aquifer Protection Area and
designated within Zone 2. According to the Washington State Wellhead
Protection Program Guidance Document (Washington Department of Health,
2010):
o Zone 2: The 5-year time-of-travel boundary for groundwater. Zone 2 is
managed to control potential chemical contaminants. All potential
contaminant sources must be addressed with emphasis on pollution
prevention and risk reduction. Zone 2 provides information local planners
use to site future "high risk" and "medium risk" potential contaminant
sources.
Aquifer Protection Area Zone 2 designation requires:
(a) The consideration of liners under stormwater facilities to protect
groundwater quality. Liners are not practical at the site and are not being
required by the City.
(b) Water quality treatment prior to stormwater infiltration, or soil conditions
that meet City stormwater treatability criteria. Water quality treatment Best
Management Practices (BMPs) are planned for the site, however soils below
the planned infiltration facilities do possess some treatability characteristics,
which will help protect groundwater quality.
• Portions of the northwest and western property boundary are within the Regulated
Slopes classified as 1) >15 percent to ≤25 percent or 2) >25 percent to ≤40
percent (Sensitive) identified within the City’s Critical Areas. A narrow strip at
the slope toe is classified as greater than 40 percent to less than or equal to 90
percent (Protected).
2.3 Geologic Setting
2.3.1 Geology
Based on our review of the geologic map (Mullineaux, 1965), the Site is underlain by
Pleistocene Vashon Stade recessional stratified drift, glaciofluvial deposits (Qpa). The
glaciofluvial deposits consist chiefly of well-sorted sand and gravel. The unit is
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subdivided according to origin and topographic form with outwash along the Cedar River
valley, sandy gravels containing cobbles in the easternmost terraces that grades to
interbedded sand and gravel in Renton and to sand near the north edge of quadrangle.
2.3.2 Faults and Seismicity
The Site is located within the Puget Lowland physiographic province, an area of active
seismicity that is subject to earthquakes on shallow crustal faults and deeper subduction
zone earthquakes. The Site area lies about 2.2 miles southwest of the southern boundary
of a concealed trace of the Seattle fault zone, which consists of shallow crustal tectonic
structures that are considered active (evidence for movement within the Holocene [since
about 15,000 years ago]) and is believed to be capable of producing earthquakes of
magnitude 7.3 or greater. The recurrence interval of earthquakes on this fault zone is
believed to be on the order of 1,000 years or more. The most recent large earthquake on
the Seattle fault occurred about 1,100 years ago (Pratt et al., 2015). There are also several
other shallow crustal faults in the region capable of producing earthquakes and strong
ground shaking.
The Site area also lies within the zone of strong ground shaking from earthquakes
associated with the Cascadia Subduction Zone (CSZ). Subduction zone earthquakes
occur due to rupture between the subducting oceanic plate and the overlying continental
plate. The CSZ can produce earthquakes up to magnitude 9.3, and the recurrence interval
is thought to be on the order of about 500 years. A recent study estimates the most recent
subduction zone earthquake occurred on January 26, 1700 (Atwater et al., 2015).
Deep intra-slab earthquakes, which occur from tensional rupture of the sinking oceanic
plate, are also associated with the CSZ. An example of this type of seismicity is the
2001 Nisqually earthquake. Deep intra-slab earthquakes typically are magnitude 7.5 or
less and occur approximately every 10 to 30 years.
2.3.3 Geologic and Seismic Hazards
Geologic and seismic hazards are defined as those conditions associated with the
geologic and seismic environment that could influence existing and/or proposed
improvements. In general, the geologic and seismic hazards most commonly associated
with the physical and chemical characteristics of near surface soil, rock, and groundwater
include the following.
Those shown in bold are the geologic and seismic hazards that could affect the Project
area’s development and should be considered during the planning process.
Geologic Hazards
• Slope stability • Adverse soils • Hydrogeology and
groundwater
• Subsurface voids • Hydrology and
drainage
• Hazardous minerals and gases
• Volcanic hazards • Land subsidence • Erosion and sedimentation
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Seismic Hazards
• Liquefaction • Lateral spreading • Fault ground rupture
• Ground shaking • Tsunamis • Earthquake-induced landslides
• Seiches
Specific hazards identified above in bold are presented in Table 2 below. The “Level of
Concern” is a qualitative assessment based on our engineering geology and geotechnical
engineering judgment. Where noted with footnotes, the terminology is taken from a
specific source (e.g., DNR webviewer).
Table 2. Geologic and Seismic Hazards Potentially Affecting the Site
Geologic and
Seismic Hazard Examples Level of Concern
Adverse Soils
Artificial Fill
Expansive Soil, Compressible
Soil, Organic-Rich Soil, Sensitive
Clay
Low to Moderate, Site was graded and filled
in areas and is an active maintenance facility
with possible buried debris and two USTs
near the former fueling station in the
center of the Site.
None to Low
Hydrology and
Drainage
Floodinga
Seiches or Standing Water
Not in FEMA 100-year flood plain
None to Low
Slope Stability Landslides and Existing Slope
Movements
Low, exception along west property boundary
Hydrogeology and
Groundwater
Shallow or artesian groundwater
Seepage
Permeability or percolation
Low
None to Low
Low
Subsurface Voids Abandoned coal minesb Low, the nearest mapped hazard zone is 0.5-
miles southwest of the Site
Seismic Hazards
Cascadia M9.0 scenarioa
Crustal – Seattle FZ M7.2
scenarioa
Local Fault Rupture
Liquefactiona
MMIc 7
MMIc 9
None to Low
Very Low
Notes: a – DNR webviewer: https://geologyportal.dnr.wa.gov/
b – City of Renton webviewer: http://rp.rentonwa.gov/HTML5Public/Index.HTML?viewer=CORMaps/
c – MMI = Modified Mercalli Intensity Scale: http://resilience.abag.ca.gov/shaking/mmi/
The primary geologic hazards that may require further evaluation during engineering
design are related to potential fill and debris. The primary seismic hazard that could
impact the Site is ground shaking from a Cascadia earthquake or Seattle fault zone
earthquake.
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2.4 Site Reconnaissance
We performed our geotechnical site reconnaissance of the Site on February 15, 2018. The
weather was cool and windy with no measurable precipitation, though about 0.25 inch of
rain had fallen on the Site during the two prior days. Much of the Site is unpaved gravel
lot with impervious surfaces including the four buildings and the driveway that leads
west from Jefferson Avenue NE into the Site. Sparse vegetation is adjacent to the
buildings and trees line the north and west property boundaries.
Topographically, the ground surface at the Site is relatively flat, with only about 5 feet of
elevation difference from the west boundary of the parcel to the east boundary, a distance
of approximately 600 feet, and no apparent elevation change across the 400 feet from the
north to the south.
A few shallow depressions (<1 inch) with standing water were observed.in low spots on
the concrete slabs and mud pits in two shallow, unpaved low spots. We did not observe
indications of concentrated surface flows across the Site, areas of groundwater seepage
from the western slopes, or of recent or ongoing soil erosion.
2.5 Subsurface Conditions
2.5.1 Previous Subsurface Explorations
King County performed six geotechnical borings on April 13, 2017 as part of their
preliminary geotechnical evaluation of the Site (Appendix E). Borings B-1 through B-5
were drilled to 26.5 feet bgs at the Site (Parcel No. 1434000012) and boring B-6 to 16.5
feet bgs for a proposed utility easement located along the west side of the adjacent
property to the north (Parcel No. 1623059130) (Figure 2, Site Exploration map).
The soils encountered were generally consistent throughout the Site and consisted of:
• GROUND SURFACE: Ground Surface to up to 0.5 bgs feet, crushed gravel
surfacing mixed with sand and silt was encountered in borings B-1 through B-5.
Boring B-6 encountered a few inches of topsoil and organic matter.
• FILL: From between 1.5 and 5 feet bgs, silty sand and mixtures of sand and
gravel were encountered in the borings with the exception of B-2, where no fill
was observed. The fill material was medium dense to dense immediately beneath
the crushed gravel surface and graded to loose with depth.
• GLACIAL OUTWASH DEPOSITS (Qpa): Outwash deposits were encountered
in the borings to the total exploration depths (26.5 bgs). The soils typically
consisted of interbedded mixtures of medium dense poorly-graded mixtures of
sand and gravel, including some cobbles and boulders.
The previous report (Appendix E) also noted potential over-sized materials may be
present and it is difficult to determine the percentage of cobbles and, potentially boulders,
in the underlying soil deposits. However, cobbles were observed and will likely be
encountered during construction, potentially with occasional small boulders.
In addition, King County’s report also identified two test pits were excavated to between
4.5 to 5.5 feet bgs during previous [no date stated] exploration of the DNRP Maintenance
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Complex property. These test pits encountered approximately 2 to 2.5 feet of medium
dense to dense gravelly sand fill overlying medium dense to dense native sand and gravel
outwash deposits, to the total excavated depths.
2.5.2 Aspect Consulting Subsurface Explorations
Subsurface conditions have been explored by Aspect during three exploration programs.
The programs included:
• On April 15 through 17, 2019, drilling two sonic borings (designated MW-01 and
MW-02) within the footprints of the West Side and East Side Stormwater
Management Facilities (see Figure 2) to depths of 75 feet bgs to install deep
infiltration test wells
• On April 13, 2018, drilling four hollow stem auger (HSA) borings (designated
AB-01 through AB-04) to depths of 26.5 feet bgs within or in the vicinity of
Building CA and Building SH footprints for geotechnical purposes
• On February 16, 2018, advancing four 15- to 20-foot bgs direct push probes
(designated AB-05 through AB-08) around the perimeter of two decommissioned
USTs for environmental purposes
The explorations were logged and soil samples collected by a geologist on the Aspect
staff. Exploration logs summarizing the subsurface conditions are presented in Appendix
A. Observations and tests were performed in general accordance with ASTM
International (ASTM) D 2488, Standard Practice for Description and Identification of
Soils (Visual-Manual Procedure). The terminology used in the soil classifications and
other modifiers are defined and presented on the attached Figure A-1 included in
Appendix A.
2.5.2.1 Soils
The summary of the subsurface units below the existing ground surface encountered in
the borings are as follows:
GROUND
SURFACE
Ground Surface to up to 0.5 bgs feet, crushed gravel surfacing mixed
with sand and silt was encountered in the borings.
FILL Between 1 and 4 feet of fill was encountered in the infiltration test well
borings (MW-01 and MW-02) and geotechnical borings (AB-01
through AB-04) consisting of loose to medium dense silty SAND (SM)
with gravel, SAND with gravel (SP), and GRAVEL with sand (GP).
Between 7 and 10 feet of fill was encountered in the environmental
direct push probes (AB-05 through AB-08) consisting of brown, silty
GRAVEL (GM) with sand and cobbles. The upper fill layer contains
some construction debris and the soil color transitioned to gray and tan
with depth.
GLACIAL
OUTWASH
DEPOSITS (Qpa)
Glacial outwash deposits were encountered in the borings underlying
the fill to the maximum exploration depth in MW-02 to 76.5 feet bgs.
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The subsurface stratigraphy consists of interbedded coarse-grained
deposits of gray and brown silty SAND (SM), SAND with silt (SP -SM
and SW-SM), SAND with silt and gravel (SP -SM and SW-SM), well-
graded and poorly-graded SAND (SW and SP) with variable gravel
content, silty GRAVEL with sand (GM), and GRAVEL with sand and
cobbles (GP and GW). A 1-foot thick layer of gravelly SILT with sand
(ML) was observed at 35 feet bgs in MW-02.
The coarse-grained deposits were medium dense to very dense with N-
values between 23 and 68 blows per foot (bpf).
2.5.2.2 Groundwater
Installation of two deep infiltration test wells included overdrilling to determine the
groundwater elevation. Groundwater was encountered over 50 ft below the bottom of the
planned stormwater infiltration trenches. Vibrating wire piezometers were installed at
approximately 75 feet bgs and have been recording groundwater levels at 30-minute
intervals. Based on readings from April 16, 2019 to April 29, 2019, including during the
stormwater infiltration tests on April 21 and April 22, the groundwater fluctuates between
67 feet and 68 feet bgs or EL 257 feet and EL 258 feet (Appendix D). No noticeable
impacts to the groundwater table were recorded during or within six days post stormwater
infiltration tests.
Groundwater was not observed in Aspect’s geotechnical or direct-push borings
(maximum depth of 26.5 feet) or in King County’s previous borings (maximum depth
26.5 feet) during previous field explorations. Groundwater depths will fluctuate due to
variations in rainfall, irrigation, and the season generally higher in the wet season from
late-November to May and lower in the dry season from June to early-November.
2.5.2.3 Environmental Contamination
During the direct-push exploration AB-05 through AB-06, soil samples were subjected to
field screening for hydrocarbon contamination. Field screening consisted of visual and
olfactory screening and screening the samples with a photoionization detector (PID). No
visual, olfactory, or PID field indications of contamination were observed.
A soil sample from each of the four borings was collected at a depth at or below the
presumed depth of the bottom of the USTs and submitted to an accredited analytical
laboratory for detection and quantification of contamination (Appendix B). The
laboratory analyzed each sample for gasoline-range organics (by method NWTPH-G) and
diesel- and oil-range organics (method NWTPH-Dx). None of the analytes were detected
at the reporting detection limits.
2.5.3 Soil Infiltration Rates
Soil infiltration rates were estimated using in situ field testing. Due to the existing
receptor soil depth, performing large-scale pilot infiltration tests (PITs) per the City of
Renton’s Surface Water Design Manual (City of Renton, 2016) was deemed impractical
because of the required excavation sizes. Aspect requested and was approved by the City
to use infiltration test wells (in lieu of Pilot Infiltration Tests [PITs]) within the footprints
of two of the four proposed stormwater systems. Measured infiltration rates were
adjusted to account for the approximate water depths within the planned infiltration
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trenches and safety factors were applied to the adjusted rates as required by the City’s
standards. Infiltration testing was in general conformance with the United States Bureau
of Reclamation (USBR)Well Permeameter Method (USBR, 1989). The measured
infiltration results indicate that the Site receptor soil has a high infiltration capacity with
an allowed design infiltration rate of 20 inches per hour (maximum allowed by the City)
for infiltration trenches.
Sandy soils are highly susceptible to plugging by stormwater sediments and the reduction
in long-term infiltration rates should be considered in the design of the stormwater
system. Typical stormwater treatment BMPs are allowed to bypass flows above the water
quality flow that could introduce some untreated, potentially sediment-containing,
stormwater into the infiltration system. This is particularly true for this Site, which
intends to retain and infiltrate all runoff up to and including the 100-year storm on site.
The need for sediment control BMPs for bypass flows, or an additional safety factor on
the design infiltration rate, should be considered by the stormwater designer to enhance
the functional life of the infiltration system.
Additional infiltration test well installation details are provided in Appendix C.
2.5.3.1 Deep Well Infiltration Tests
The infiltration rates of the planned receptor soil (proposed to be at depths of 10 feet to
15 feet bgs) were tested in 6-inch-diameter monitoring wells screened from 13 feet to 23
feet bgs in MW-01 and from 15 feet to 25 feet bgs in MW-02, both within the target
infiltration receptor soil. We conducted two two-phase infiltration tests in general
accordance with the United States Bureau of Reclamation (USBR)Well Permeameter
Method (USBR, 1989); consisting of a constant head test (Phase 1) and falling head test
(Phase 2).
Due to the high permeability of the Site’s receptor soils and access to finite water source
from 5,000-gallon water trucks, producing, maintaining, and measuring constant head
levels during the tests were a challenge. Rather than measuring stepped water levels and
rates, the tests consisted of using the maximum allowable flow rates the equipment was
capable of providing, which was between 90 and 140 gallons per minute (gpm). Table 3
below provides the constant head test details.
Table 3. Field Infiltration Test Results
Monitoring Well Time Interval
(hr)
Flow Rates
(gpm)
Constant
Head (ft ht)
Total
(gal)
MW -01
1.5 84 7.6
13,210 0.5 97 7.8
0.5 115 9.3
MW -02 0.5 120 6.2 27,700 3.25 120 5.1
The Phase 2 Falling Head tests recorded rapid drops in head once the water source was
shut-off, with 50 to 80 percent recovery within 2 minutes and 95 percent or greater within
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5 minutes. Evidence of post-test perched groundwater was not observed in the infiltration
test wells, suggesting no discernable presence of restrictive soil layers or related
mounding of the water used during the tests. In addition, the vibrating-wire piezometers
data recorded during the tests and for six days after were analyzed for fluctuations in the
groundwater elevation that could be attributed to the test. No significant groundwater
mounding response was observed, indicating that the groundwater likely has ample
capacity to absorb infiltrated stormwater.
2.5.3.2 Soil Treatability Tests
We understand the proposed plan is to implement stormwater treatment BMPs prior to
infiltration. To evaluate the receptor soil for treatment functions to increase groundwater
quality protection, soil samples from MW-01 at 20 feet bgs and MW-02 at 35 feet bgs
were tested for cation exchange capacity (CEC) and organic matter percentage.
For the soil to count as stormwater treatment within a designated Aquifer Protection
Zone, City standards require that at least the first two feet of soil below an infiltration
facility to: (1) have a CEC of at least 5.0 milliequivalents/100 grams of soil (meq/100g);
(2) have an Organic Matter Content of 1 percent or greater by dry weight (for soil
fraction passing the #40 sieve); (3) have measured infiltration rates less than or equal to 9
inches per hour, and meet specific soil gradation requirements (Section 5.2 of the 2016
City Surface Water Design Manual; City of Renton, 2016).
The CEC and organic percentage results for the samples taken were 4.2 meq/100g of soil
and 1.6 percent in MW-01 and 5.0 meq/100g of soil and 1 percent in MW-02. The
sample from MW-01 is slightly below the CEC minimum 5 meq/100 grams requirement
while the organic content is greater than the minimum. The sample from MW-02 is
equivalent to or above both minimum requirements. While the Site soil does have a
measured infiltration rates significantly higher than 9 inches per hour, the soil does have
the ability to provide some treatment of infiltrating stormwater through filtration, cation
exchange, and adsorption, which will enhance the protection of groundwater quality
when compared to the planned basic treatment BMPs alone.
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3 Conclusions and Recommendations
3.1 General
Based on our geotechnical evaluation of the Site, including data review, Site
reconnaissance, subsurface explorations, and laboratory testing, the following key
preliminary findings and conclusions should be included in further evaluating the Site:
The upper soils encountered in the explorations within the anticipated foundation
excavation depths are medium dense to dense sand and gravel soils. The fill and
glacial outwash deposits may contain cobbles and boulders that could be
encountered during earthwork and require removal.
The area surrounding the two decommissioned USTs near the former fueling
station in the center of the Site did not have indications of contaminated soil.
Although no field or laboratory indications of product release from the USTs
were measured or observed, the steel USTs could have leaked while they were in
service. Because the soils around and below the USTs are coarse-grained and
permeable, any release from the USTs would have migrated vertically. If the
tanks will be removed as part of the construction, we recommend field-screening
the soil directly under the tanks for indications of contamination and, if detected,
completing additional analytical laboratory tests.
Shallow spread footings are an appropriate foundation type for Buildings CA,
SH, and ST.
Glacial outwash sands and sandy gravels are generally well suited for stormwater
infiltration. The Site’s designation as a Aquifer Protection Area Zone 2 requires
water quality treatment prior to infiltrating stormwater. While water quality
treatment is required prior to infiltration, chemical testing indicates that the soil
does have the ability to provide some treatment of infiltrating stormwater through
filtration, cation exchange, and adsorption.
Groundwater was encountered in our explorations at approximately 67 feet bgs,
greater than 50 feet below the soil receptor depth of 10 to 15 feet bgs for the
currently proposed stormwater infiltration facilities.
From a geotechnical perspective, typical activities associated with site
development such as clearing and grading, utility placement, and building
construction will have no adverse impacts on surrounding properties provided
County and/or other regulatory requirements for design and construction are
implemented.
We anticipate cuts and fills will generally be less than 4 feet over most of the Site, with
the exception of the planned stormwater trenches to about 15 feet bgs. From a
geotechnical perspective, earthwork excavation using conventional equipment will be
feasible during construction.
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3.2 Seismic Design Criteria
Inertial seismic forces are expected to affect the Site and structures. Appropriate design
of structures in accordance with the current version of the International Building Code
(IBC) with State of Washington amendments will mitigate seismic hazards.
The IBC requires design for a “Maximum Considered Earthquake (MCE)” with a
2 percent probability of exceedance (PE) in 50 years (2,475-year return period; IBC,
2015). The U.S. Geological Survey (USGS) has completed probabilistic ground motion
studies and maps for Washington (USGS, 2014).
Current IBC design methodologies express the effects of site-specific subsurface
conditions on the ground motion response in terms of the “site class.” The site class can
be correlated to the average standard penetration resistance (SPT) in the upper 100 feet of
the soil profile. Based on the results of the previous subsurface exploration program and
using the 2015 IBC criteria, we recommend the Site be characterized by a Seismic Site
Class D.
Based on the Site’s latitude and longitude (47.488°N, 122.178°W), the code-based
seismic design criteria, in accordance with the 2015 IBC, are summarized in Table 4.
Table 4. 2018 IBC Seismic Design Parameters
Parameter Short Period 1 Second
Maximum Credible Earthquake Spectral Acceleration Ss = 1.42 g S1 = 0.53 g
Site Class D
Site Coefficient Fa = 1.00 Fv = 1.56
Adjusted Spectral Acceleration SMS = 1.42 g SM1 = 0.80 g
Design Spectral Response Acceleration Parameters SDS = 0.94 g SD1 = 0.53 g
Design Spectral Peak Ground Acceleration 0.58 g
Notes:
g = acceleration due to gravity
3.3 Foundation Design
3.3.1 Shallow Foundations
Based on our observations of the subsurface conditions at the Site, shallow foundations
on spread or strip footings may be used for building support. We recommend the footings
bear directly on sandy and gravelly, medium dense to dense Qpa soil deposits, if exposed
by grading, or the footings should be over-excavated by 18 to 24 inches and replaced
with compacted structural fill. The structural fill below the footings should extend
beyond the edges of the footings by a distance equal to the thickness of the structural fill.
The exposed subgrade surface of all footings should be evaluated by a qualified
geotechnical engineer. Design parameters are provided in Table 5.
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Table 5. Spread Footing Foundation Design Recommendationsa
Design Item Design Information
Structures Renton Shop Buildings
Bearing Material
Qpa deposits or 18 to 24 inches of compacted structural fill
placed over approved subgrade
Allowable Bearing Pressurea 2,500 psf
Minimum Embedment
Depthb,c 18 inches
Total Estimated Settlement
Differential Settlement
Less than 1 inch
Less than ½-inch between adjacent footings
Notes:
a) Designs are based on the subsurface conditions encountered in the explorations and assumes
the recommendations in the Construction Considerations Section will be adhered to.
b) For preliminary information related to minimum depth of footing for frost action. Does not infer
or indicate depth to bearing strata. Will be updated at final design.
c) The recommended allowable bearing pressure applies to the total of dead plus long-term-live
loads. Allowable bearing pressures may be increased by one-third (⅓) for seismic and wind
loads.
For use in design, an ultimate coefficient of friction of 0.45 may be assumed along the
interface between the base of a cast-in-place concrete footing and the subgrade soils. An
ultimate passive earth pressure of 450 pounds per cubic foot (pcf) may be assumed for
structural fill replacement or gravel soils adjacent to below-grade elements. The upper
1 foot of passive resistance should be neglected in design. The recommended coefficient
of friction and passive pressure values are ultimate values that do not include a safety
factor. We recommend applying a factor of safety of at least 1.5 in design for determining
allowable values for coefficient of friction and passive pressure.
3.4 Floor Slabs and Modulus of Subgrade Reaction
Concrete slabs-on-grade should be designed in accordance with the American Concrete
Institute (ACI) Committee’s 360R-10 Guide to Design of Slabs-on-Ground (ACI, 2010).
For slabs that are designed as beam-on-elastic foundation, a modulus of vertical subgrade
reaction of 150 pounds per cubic inch (pci) may be utilized. Satisfactory support for
building floor slabs can be obtained from the sandy and gravelly, medium dense to dense
Qpa soil subgrades or the 18 to 24 inches of structural fill replacement and be prepared in
accordance with our recommendations presented in the Site Preparation and/or Wet-
Weather/Wet-Soil Conditions sections of this report (Sections 4.2 and 4.4, respectively).
A minimum 6-inch-thick layer of imported granular material should be placed and
compacted over the prepared subgrade. Imported granular material should be composed
of crushed rock or crushed gravel that is relatively well-graded between coarse and fine,
contains no deleterious materials, has a maximum particle size of 1 inch, and has less
than 5 percent by dry weight passing the US Standard No. 200 Sieve.
3.5 Pavement Design
Traffic volume estimates and loading patterns were not provided at the time of this
report. We anticipate that parking and ancillary access drives will primarily be paved
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with hot mix asphalt (HMA) pavement. Without traffic volume information to complete a
pavement design, the general pavement section recommendation is in accordance with
the King County Roads Standards (King County, 2016). Work should be performed in
accordance with King County Standard Specifications (KCSS) Section 32 12 16 -
Asphalt Paving (KCSS, 2018).
The main drive lanes entering and leaving the Site and areas of the buildings where
maintenance vehicles will frequently be using, including loading ramps, should consider
more robust HMA pavement sections or using portland cement concrete (PCC). For
planning purposes pavement sections are shown in Table 6 below.
Table 6. Preliminary Pavement Section
Material
Parking areas and
ancillary drive lanes
Loading ramps and main
drive lanes
HMA HMA PCC
HMA CLASS ½”
(wearing course) 2 2 in
HMA CLASS ½”
(leveling course) 2 3.5
PCC 8
CSBC 8.5 12 6
3.6 Stormwater Management Design
The general coarse-grained soil uniformity encountered in Aspect’s and King County’s
previous explorations underlying the Site below approximately 10 to 15 feet bgs provides
an opportunity to install infiltration trenches for on-site stormwater management.
Infiltration trench galleries will be designed at four locations at the Site.
Due to the design soil receptor depth, performing large-scale pilot infiltration tests (PITs)
per the City (City of Renton, 2016) was deemed impractical because of the required
excavation sizes. Aspect requested and was approved by the City to use deep infiltration
test wells to measure receptor soil infiltration rates within the footprints of two of the four
proposed infiltration galleries.
3.6.1 Steep Slope Setback and Groundwater Considerations
The City requires infiltration facilities consider the effects of stormwater injection on
slope stability and groundwater aquifers from the injection point. Per Table 6.2.3.A
Setback Requirements within the City’s Surface Water Design Manual (City of Renton,
2016), Geotechnical Setbacks are to consider:
• Facilities are not allowed on slopes >25 percent (4:1). A geotechnical analysis
and report are required if located within 200 feet of a steep slope hazard area or
landslide hazard or if the facility is located within a setback distance from top of
slope equal to the total vertical height of a slope area that is steeper than 15
percent. The geotechnical analysis must consider cumulative impacts from the
project and surrounding areas under full built-out conditions.
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• The facility design water surface should be a minimum of 200 feet from any steep
slope hazard area or landslide hazard. Upon analysis and approval of a licensed
geotechnical engineer or engineering geologist, this setback may be reduced to 50
feet. The geotechnical analysis must consider cumulative impacts from the
project and surrounding areas under full built-out conditions.
• The facility design water surface should be set back a minimum distance from top
of slope equal to the total vertical height of a slope area that is steeper than 15
percent. Upon analysis and approval of a licensed geotechnical engineer or
engineering geologist, this setback may be reduced to 50 feet. The geotechnical
analysis must consider cumulative impacts from the project and surrounding
areas under full built-out conditions.
The proposed location for the stormwater management facility on the Site’s west side
will be adjacent to a channel and approximately 50 feet from Regulated Slopes classified
as 1) >15 percent to ≤25 percent or 2) >25 percent to ≤40 percent (Sensitive Slope)
identified within the City’s Critical Areas. The facility will also be approximately 125
feet from a small, narrow strip at the slope toe shown as Regulated Slopes classified as
greater than 40 percent to less than or equal to 90 percent (Protected).
Since the proposed stormwater management facility soil receptor will be 10 feet to 15
feet bgs (EL 315 feet [Sheet UD-204, HDR, 2019]), the injection surface will be at the
same elevation to 5 feet below the base of the adjacent channel at EL 315 to 320 feet. In
our opinion, stormwater injection below El 315 feet will not affect slope stability within
or surrounding the Site and the facility’s proposed location of 50 feet from the top of
slope is suitable.
The City of Renton’s Surface Water Design Manual (City of Renton, 2016) requires
groundwater investigations, including:
• Mounding analyses for infiltration facilities that serve 1 acre or more of tributary
area and have less than 15 feet of separation to a restrictive layer or groundwater
table
• Investigating the groundwater regime for flow control design if within 50 feet
from the facility base
The groundwater depths recorded in the piezometers (see Appendix D) have been
between 52 and 53 feet below the injection point. Therefore, mounding analyses and
additional assessment of the groundwater regime are not necessary for the proposed
stormwater management facilities.
3.6.2 Infiltration Test Analyses and Infiltration Gallery Design
Full-scale infiltration design recommendations have been developed to account for: (a)
the MW-01 and MW-02 infiltration test results; (b) standard safety factors; (c) the level
of variability and uncertainty in site soils; (d) the potential to encounter perched water
above the receptor soil; and (e) additional allowance for the long-term reduction in
hydraulic conductivity due to biofouling or plugging with sediment.
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The Well Permeameter Method (USBR, 7300-89) was used to measure infiltration flow
rates and estimate the bulk hydraulic conductivity for the receptor soil. Test results were
also used to estimate the design infiltration rates for the proposed infiltration trench
gallery stormwater management facilities. The infiltration rates measured during
infiltration testing were derived by dividing the constant flow rate by the approximate
surface area being infiltrated across (surface area of the submerged 10-inch-diameter
borehole outside the 6 inch-diameter well screen). The measured infiltration rates were
reduced to account for the lower operating head expected in the infiltration trench
galleries, and further reduced to account for safety factors specified in the City standards.
The initial estimates of design infiltration rates exceeded the City’s maximum allowed
rate of 20 in/hr. Table 7 provides the design infiltration results for MW-01 and MW-02.
Table 7. Infiltration Analyses Results and Design Parametersa
Parameter Unit MW-01 MW-02
IMeasured Unit in/hr/ft 53 167 Measured infiltration rate on per foot of head
basis.
HFacility ft 1.5 1.5 Assumed average head in proposed
infiltration facility.
IMeasured Facility in/hr 79.80 250.73 Measured infiltration rate, adjusted for
proposed facility head.
FTesting -- 0.5 0.5 Correction factor accounting for uncertainty in
testing method.
FGeometrya -- 1 1 Correction factor accounting for influence of
facility geometry1.
FPlugging -- 0.85 0.85
Correction factor accounting for reduction in
filtration rate over the long term due to
plugging of soils.
IDesign in/hr 33.91 106.56 IDesign = IMeasured Facility x FTesting x FGeometry x
FPlugging
IDesign Final in/hr 20.00 20.00
Final design infiltration rate must not exceed
20 in/hr per City of Renton Surface Water
Design Manual Section 5.2.1.
Notes: a) FGeometry = 4 D/W + 0.05 = 7.38 where, D = depth from bottom of the proposed facility to the
maximum wet-season water table ~ 55 ft, and W = width of facility ~ 30 ft. FGeometry must be
not greater than 1.0.
Due to the Site’s subsurface soil uniformity, similar groundwater depth/elevations, and
comparable infiltration test parameters and results, additional infiltration tests are not
recommended to further characterize conditions.
City standards allow stormwater design to proceed using the maximum infiltration rate
permissible in the City of Renton Surface Water Design Manual (20 inches per hour).
However, as discussed above, Aspect notes that sandy soils are highly susceptible to
plugging by stormwater sediments. Typical stormwater treatment BMPs are allowed to
bypass flows above the water quality flow, which could introduce some untreated,
potentially sediment containing, stormwater into the infiltration system. This is
particularly true for this Site, which intends to retain and infiltrate all runoff up to and
including the 100-year storm on site. Therefore, the need for sediment control BMPs for
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bypass flows, or an additional safety factor on the design infiltration rate, should be
considered by the stormwater designer to enhance the functional life of the infiltration
system.
3.6.3 Water Quality Treatment and Underground Injection Control
As required by the City, stormwater runoff should be treated prior to discharging to the
infiltration system. Aspect recommends including pretreatment (sediment, floatables, and
oil) for water quality BMP overflows during larger storm events since this otherwise
untreated water will be directed into the infiltration system rather than to off-site drainage
systems or surface waters for up to and including the 100-year storm event.
Infiltration trench galleries that contain perforated pipe will be considered Underground
Injection Control (UIC) facilities under the State’s UIC program and will require
registration with the Washington State Department of Ecology prior to being put into use.
Based on the City’s standards (5.2.1 of the 2017 City of Renton surface Water Design
Manual), UIC wells must be registered and registration documentation must be provided
to the City prior to stormwater plan review and/or approval.
Typically, Ecology requires UIC facilities to be registered during the design process, and
then updated based on construction as-builts. This process allows: (1) Ecology to review
the UIC design and comment if they deem necessary; (2) the designer to address any
comments prior to construction; and (3) the registration to be updated to reflect as-
constructed conditions. Aspect can assist in the UIC registration process if needed.
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4 Construction Considerations
4.1 General
Earthwork is typically most economical when performed under dry weather conditions.
Appropriate erosion control measures should be implemented prior to beginning
earthwork activities in accordance with the local regulations. In our opinion, excavation
can generally be accomplished using standard excavation equipment. While not directly
observed in Aspect’s subsurface explorations, the presence of potential obstructions, such
as small boulders, buried logs, or other debris, in the fill or other deposits should be
anticipated.
4.2 Site Preparation
Site preparation within the proposed construction footprint should include removal of fill
and soils containing roots, organics, debris, and any other deleterious materials in
accordance with KCSS Section 31 10 00 – Site Clearing, KCSS Section 31 22 00 –
Grading, KCSS Section 31 23 00 – Excavation & Fill, and KCSS Section 31 23 12 –
Subgrade Preparation (KCSS, 2018). The contractor must use care during Site
preparation and excavation operations, so that any bearing surfaces are not disturbed. If
disturbance does occur, the disturbed material should be removed to expose undisturbed
material or be compacted in place to acceptable criteria as determined by the geotechnical
engineer.
All footing excavations should be trimmed neat and the bottom of the excavation should
be carefully prepared. All loose or softened soil should be removed from the footing
excavation or compacted in place prior to placing reinforcing steel bars. We recommend
the footing excavations be observed by the geotechnical engineer to assess the presence
of fill, evaluate the subgrade condition, and provide depths of over-excavation and
replacement with structural fill prior to placing steel and concrete to verify the
recommendations in this report have been followed.
The subgrade under the HMA pavement section areas should be prepared by scarifying,
moisture conditioning, and recompacting a minimum of 12 inches below the bottom of
the base course. Materials generated during earthwork should be transported off-site or
stockpiled in areas designated by the owner’s representative.
4.3 Proofrolling and Subgrade Verification
Following Site preparation, subgrade to support structural fill, footings, floor slabs,
pavements, hardscapes, and any other structures should be evaluated either by proof
rolling or another method of subgrade verification. The subgrade should be proofrolled
per KCSS Section 31 22 00 – Grading with a fully loaded tandem dump truck with a
minimum total gross vehicle weight of 44,000 pounds or articulated dump truck to
identify unsuitable areas. If evaluation of the subgrades occurs during wet conditions, or
if proofrolling the subgrades will result in disturbance, they should be evaluated by
Aspect using a steel foundation probe. We recommend that Aspect be retained to observe
the proofrolling and perform the subgrade verifications. Unsuitable areas identified
during the field evaluation should be compacted to a firm condition or be excavated and
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replaced with structural fill meeting requirements of KCSS Section 31 23 00 –
Excavation and Fill.
4.4 Wet Weather Conditions
If earthwork is to be performed or fill is to be placed in wet weather or under wet
conditions, when soil moisture content is above optimum and difficult to control, the
following recommendations apply:
Contractor is responsible for recognizing inclement weather occurs during the
construction season, and the contractor is responsible for protecting the moisture
condition of soils during the construction phase.
Earthwork should be performed in small areas to minimize exposure.
Structural fill placed during wet weather should consist of material meeting the
criteria for Granular Borrow as specified in KCSS 31 23 00, Part 2 Products, 2.1
Material, F.
Excavation or the removal of unsuitable soils should be followed promptly by the
placement and compaction of the specified structural fill.
The size, type, and access of construction equipment used may have to be limited
to prevent soil disturbance.
The ground surface within the construction area should be graded to promote
runoff of surface water away from the slopes and to prevent water ponding.
The ground surface within the construction area should be properly covered and
under no circumstances should be left uncompacted and/or exposed to moisture.
Soils that become too wet for compaction should be removed and replaced with
specified structural fill.
Excavation and placement of fill should be observed by the geotechnical engineer
to verify that all unsuitable materials are removed prior to placement, compaction
requirements are met, and site drainage is appropriate.
Erosion and sedimentation control should be implemented in accordance with
BMPs.
4.5 Excavation
4.5.1 General
The near-surface soils at the Site can be excavated with conventional earthwork
equipment. Sloughing and caving should be anticipated in loose, non-cohesive materials.
Aspect should be retained to review the grading and utility plans when they become
available for comparison with encountered field conditions; additional work may be
required to better define the impact on the Project.
4.5.2 Trenches
Trench cuts should stand relatively vertical to a depth of approximately 4 feet bgs,
provided no groundwater seepage is present in the trench walls. Open excavation
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techniques may be used in the clay, silt, silty sand, and sandy silt, provided the
excavation is configured in accordance with the U.S. Occupational Safety and Health
Administration (OSHA) requirements, groundwater seepage is not present, and with the
understanding that some sloughing may occur. The trenches should be flattened if
sloughing occurs or seepage is present. If shallow groundwater is observed during
construction, use of a trench shield or other approved temporary shoring is recommended
for cuts that extend below groundwater seepage, or if vertical walls are desired for cuts
deeper than 4 feet bgs. If dewatering is used, we recommend that the type and design of
the dewatering system be the responsibility of the contractor, who is in the best position
to choose systems that fit the overall plan of operation.
4.5.3 Temporary and Permanent Slopes
With time and the presence of seepage and/or precipitation, the stability of temporary
unsupported cut slopes can be significantly reduced. We recommend planning the
construction schedule to have excavation occur during the summer months and to
minimize the amount of time that the temporary slopes will be unsupported during
construction. The contractor should monitor the stability of the temporary cut slopes and
adjust the construction schedule and slope inclination accordingly. Vibrations created by
traffic and construction equipment may cause caving and raveling of the face of the
temporary slopes. At no time should soil stockpiles, equipment, and other loads be placed
immediately adjacent to an excavation.
In general, shallow surface soils, such as topsoil and unconsolidated soils that will be
subject to excavation and sloping on the Site, classify OSHA Soil Classification Type C.
These soils are expected to fail at steep angles. Temporary excavation side slopes (cut
slopes) are anticipated to stand as steep as 1.5H:1V within the topsoil and unconsolidated
soils. The cut slope inclinations estimated above are for planning purposes only and are
applicable to excavations without inflowing perched groundwater or runoff.
Permanent slopes for the project should have a maximum inclination of 2H:1V. Access
roads and pavements should be located at least 5 feet from the top of temporary slopes.
Surface water runoff should be collected and directed away from slopes to prevent water
from running down the face.
4.6 Structural Fill Materials and Compaction
Structural fill, including base rock, should be placed over subgrades that have been
prepared in conformance with the Site Preparation and Wet Weather Conditions sections
of this report (Sections 4.2 and 4.4, respectively). Source material may be derived from
on-site sources or imported.
The suitability of excavated soils for reuse as structural fill depends on the gradation and
moisture content when it is placed. As the fines percentage (percent passing through a
U.S. No. 200 sieve) increases, the soil becomes increasingly sensitive to small changes in
moisture content and adequate compaction becomes more difficult. Soil containing more
than about 5 percent fines cannot be consistently compacted to a dense, non-yielding
condition when the moisture content is greater than 3 to 4 percent above or below
optimum. Soil considered for use as structural fill must also be free of organics and other
compressible materials.
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Results of laboratory analysis (grain-size analysis) indicate the majority of the excavation
soils at the Site will have a fines content below 5 percent (by weight). These materials
should be acceptable to reuse as structural fill if properly moisture conditioned and
placed and compacted during dry weather. Import fill may be required if earthwork is
planned for the wet season. Soil reuse as structural fill should be evaluated during
construction on a case-specific basis.
General fill specifics are provided in Table 8.
Table 8. Fill Type and Compaction Requirements
Fill Type KCSS Details
Lift Thicknessa and
Compaction Requirementsb
Onsite Soil KCSS Section 31 23 00, Part 2
Products, 2.1 Material, B – Common
8 to 12 inches
Dependent on Application
Imported Granular
Materials
KCSS Section 31 23 00, Part 2
Products, 2.1 Material, D – Select
Borrowc
9 inches
95 percent
Crushed Aggregate
Base
KCSS Section 31 11 23, Part 2
Products, 2.1 – Aggregated
9 inches
95 percent
Foundation Base
Aggregate
KCSS Section 31 23 00, Part 2
Products, 2.1 Material, D – Select
Borrowc
9 inches
95 percent
Trench Backfill KCSS Section 31 23 33, Part 2
Products, 2.1 – Pipe Embedment
Materiale
KCSS Section 31 23 33, Part 2
Products, 2.5 –Backfill Materialf
KCSS Section 31 23 33, Part 2
Products, 2.5 –Backfill Materialg
9 inches
90 percenth
9 inches
90 percenth
9 inches
95 percenti
9 inches
90 percenth
Notes:
a) Maximum uncompacted thickness
b) Maximum dry density, as determined by ASTM D1557
c) Equivalent to WSDOT SS 9-03.14(2) – Select Borrow. Fraction passing the US Standard No. 4
Sieve, less than 5 percent by dry weight should pass the US Standard No. 200 Sieve.
d) Equivalent to WSDOT SS 9-03.9(3) – Crushed Surfacing Base Course
e) Trench backfill placed beneath, adjacent to, and for at least 6 inches above utility lines (i.e., the
pipe embedment zone)
f) Within pavement areas or beneath building pads
g) Outside of structural improvement areas (e.g., roadway alignments or building pads), trench
backfill placed above the pipe zone
h) Or per manufacturer / local building department i) Within 2 feet below final grade or pavement
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4.7 Ground Moisture
4.7.1 General
The perimeter ground surface and hard-scaping should be sloped to drain away from all
structures and away from adjacent slopes. Gutters should be tight-lined to a suitable
discharge and maintained as free-flowing. Any crawl spaces should be adequately
ventilated and sloped to drain to a suitable, exterior discharge.
4.7.2 Perimeter Footing Drains
Due to the potential for perched groundwater, Aspect recommends perimeter foundation
drains be installed around all proposed structures.
The foundation subdrainage system should include a minimum 4-inch-diameter
perforated pipe in a drain rock envelope. A nonwoven geotextile filter fabric, such as
Mirafi 140N or equivalent, should be used to completely wrap the drain rock envelope,
separating it from the native soil and footing backfill materials. The invert of the
perimeter drain lines should be placed approximately at the bottom of footing elevation.
Also, the subdrainage system should be sealed at the ground surface. The perforated
subdrainage pipe should be laid to drain by gravity into a non-perforated, solid pipe and
finally connected to the Site drainage stem at a suitable location. Water from downspouts
and surface water should be independently collected and routed to a storm sewer or other
outlet. This water must not be allowed to enter the bearing soils.
4.8 Construction-Phase Stormwater Considerations
4.8.1 Protection and Verification of Infiltration Receptor Soils
In addition to applying construction erosion and sediment controls as required by the City
(and potentially the State), site preparation, grading, and other construction work must:
a. Protect infiltration receptor soils from exposure to sediments due to erosion or
contact with finer-grained soils, both of which could compromise infiltration rates
b. Protect infiltration receptor soils from compaction, which could compromise
infiltration rates
c. Protect all constructed stormwater drainage facilities from sediment entry during
construction
d. Include inspection and, if needed, flushing and cleaning of drainage system
components to remove any accumulated sediment from the system prior to
allowing any flow to enter the infiltration system. Any water used for flushing or
cleaning must not be allowed to enter the infiltration system.
e. Verify that the drainage area for each infiltration gallery is fully stabilized and
erosion resistant prior to allowing any flow into the infiltration galleries
Excavation and construction of the infiltration galleries should include ample observation
to verify receptor soils are properly protected and are consistent with the soils used to
determine the design infiltration rates. Any observations of finer and potentially flow
restricting soils in the infiltration gallery area should be reported to the design engineer
ASPECT CONSULTING
PROJECT NO. 170383 - TASK 400 MAY 31, 2019 DRAFT 25
for assessment and determination of whether any design changes or other actions are
warranted.
4.8.2 Geotextiles for Stormwater Drainage
Geotextiles that will be expected to pass water while being exposed to soil and/or
sediments over time, such as those used in stormwater infiltration systems, should be
woven mono-filament (non-split tape) fabric with a relatively high percent open area and
relatively small opening size. Needle punched non-woven materials are not
recommended. Geotextiles suitable for drainage pass-through applications would meet
specifications similar to:
a. Woven mono-filament geotextile
b. Permittivity per ASTM D 4491 of 1.0 sec-1 minimum
c. Water flow rate per ASTM D 4491 of 150 gpm/ft2 minimum
d. Percent open area per CW-02215 of 15% minimum
e. Maximum Apparent Opening Size (AOS) per ASTM D 4751 of 20 US Std.
Sieve (0.84 mm)
ASPECT CONSULTING
26 DRAFT PROJECT NO. 170383 - TASK 400 MAY 31, 2019
5 Project Design and Construction Monitoring
At the time of this report, site plans, site grading, structural plans, and construction
methods have not been finalized, and the recommendations presented herein are based on
preliminary project information. Additional work including geotechnical explorations and
infiltration tests, engineering analyses, and geotechnical design recommendations will be
needed for the selected, preferred alternative development.
This report is issued with the understanding that the information and recommendations
contained herein will be brought to the attention of the appropriate design team personnel
and incorporated into the project plans and specifications, and that the necessary steps
will be taken to verify that the contractor and subcontractors carry out such
recommendations in the field. We do not direct the contractor’s operations, and we
cannot be responsible for the safety of personnel other than our own on the Site; the
safety of others is the responsibility of the contractor. The contractor should notify the
property owner if he considers any of the recommended actions presented herein unsafe.
We are available to provide geotechnical engineering and monitoring services during
construction. The integrity of the foundation depends on proper site preparation and
construction procedures. In addition, engineering decisions may have to be made in the
field in the event that variations in subsurface conditions become apparent.
ASPECT CONSULTING
PROJECT NO. 170383 - TASK 400 MAY 31, 2019 DRAFT 27
6 References
American Concrete Institute (ACI), 2010, Guide to Design of Slabs-on-Ground, Reported
by ACI Committee 360, April 2010.
ASTM International (ASTM), 2017, 2017 Annual Book of ASTM Standards, West
Conshohocken, Pennsylvania.
Atwater, B.F., Musumi-Rokkaku, S., Satake, K., Tsuji, Y., Ueda, K., and Yamaguchi,
D.K., 2015, The orphan tsunami of 1700—Japanese clues to a parent earthquake
in North America, 2nd ed.: Seattle, University of Washington Press, U.S.
Geological Survey Professional Paper 1707, 135 p.
City of Renton, 2018, Maps of Your Community online portal , Website,
http://rp.rentonwa.gov/HTML5Public/Index.HTML?viewer=CORMaps,
Accessed March 1, 2018.
City of Renton, Surface Water Design Manual, Public Works Department, Surface Water
Utility, December 12, 2016.
HDR, Inc. (HDR), 2019, King County Parks – Renton Shop, 60 Percent Design Plan Set,
KC PARKS Project #1122161, dated January 15, 2019.
International Building Code (IBC), 2015, International Building Code. Prepared by
International Code Council, January.
King County, 2016, Road Design and Construction Standards, Department of
Transportation, Road Services Division, 18420 Attachment A, revised
November 28, 2016.
King County, 2018, King County Standard Specifications (KCSS).
King County, King County Interactive Mapping Program (iMap) Web Portal, website
https://gismaps.kingcounty.gov/iMap/, Accessed March 1, 2018.
Mullineaux, D. R., 1965, Geologic map of the Renton quadrangle, King County,
Washington, U.S. Geological Survey, Geologic Quadrangle Map GQ-405, 1
sheet, scale 1:24,000.
Pratt, T.L., K.G. Troost, J.K. Odum, and W.J. Stephenson, 2015, Kinematics of shallow
backthrusts in the Seattle fault zone, Washington State, Geosphere, v. 11, no. 6, p.
1–27, doi:10.1130/GES01179.1.
United States Bureau of Reclamation (USBR), 1989, Procedure for Performing Field
Permeability Testing by the Well Permeameter Method (USBR 7300-89).
United States Geological Survey (USGS), 2014, U.S. Seismic Design Maps, Page Last
Modified: January 30, 2017 18:07:40 UTC, Website,
http://earthquake.usgs.gov/designmaps/us/application.php, Accessed
March 1, 2018.
ASPECT CONSULTING
28 DRAFT PROJECT NO. 170383 - TASK 400 MAY 31, 2019
Washington Department of Ecology (Ecology), 2014, Stormwater Management Manual
for Western Washington, Publication Numbers 12-10-030, As amended
December 2014.
Washington Department of Health, 2010, Washington State Wellhead Protection
Program Guidance Document, June 2010.
Washington Department of Natural Resources (DNR), 2017, Interactive Geologic Map,
Website: https://geologyportal.dnr.wa.gov/, Division of Geology and Earth
Resources, Accessed March 1, 2018.
Washington State Department of Transportation (WSDOT), 2016, Standard
Specifications for Road, Bridge and Municipal Construction, Document M 41-10.
ASPECT CONSULTING
PROJECT NO. 170383 - TASK 400 MAY 31, 2019 DRAFT 29
7 Limitations
Work for this project was performed for HDR Architecture, Inc. (Client), and this report
was prepared consistent with recognized standards of professionals in the same locality
and involving similar conditions, at the time the work was performed. No other warranty,
expressed or implied, is made by Aspect Consulting, LLC (Aspect).
Recommendations presented herein are based on our interpretation of site conditions,
geotechnical engineering calculations, and judgment in accordance with our mutually
agreed-upon scope of work. Our recommendations are unique and specific to the project,
site, and Client. Application of this report for any purpose other than the project should
be done only after consultation with Aspect.
Variations may exist between the soil and groundwater conditions reported and those
actually underlying the site. The nature and extent of such soil variations may change
over time and may not be evident before construction begins. If any soil conditions are
encountered at the site that are different from those described in this report, Aspect
should be notified immediately to review the applicability of our recommendations.
It is the Client's responsibility to see that all parties to this project, including the designer,
contractor, subcontractors, and agents, are made aware of this report in its entirety. At the
time of this report, design plans and construction methods have not been finalized, and
the recommendations presented herein are based on preliminary project information. If
project developments result in changes from the preliminary project information, Aspect
should be contacted to determine if our recommendations contained in this report should
be revised and/or expanded upon.
The scope of work does not include services related to construction safety precautions.
Site safety is typically the responsibility of the contractor, and our recommendations are
not intended to direct the contractor’s site safety methods, techniques, sequences, or
procedures. The scope of our work also does not include the assessment of environmental
characteristics, particularly those involving potentially hazardous substances in soil or
groundwater.
All reports prepared by Aspect for the Client apply only to the services described in the
Agreement(s) with the Client. Any use or reuse by any party other than the Client is at the
sole risk of that party, and without liability to Aspect. Aspect’s original files/reports shall
govern in the event of any dispute regarding the content of electronic documents
furnished to others.
Please refer to Appendix F titled “Report Limitations and Guidelines for Use” for
additional information governing the use of this report.
FIGURES
^GIS Path: T:\projec ts_8\KingCountyParksMaintenanc eFac ility_170383\Delivered \ Geotec hnicalReport_30Perc ent\ 01 Site Loc ation Map.m xd || Coord inate System : N AD 1983 StatePlane Washington N orth FIPS 4601 Feet || Date Saved : 5/20/2019 || User: ecrum b aker || Print Date: 5/20/2019
Site Location MapGeotec hnic al Report - 30 Perc entKing County Parks and Rec reation Division – Renton Shop 3005 N E 4th StreetRenton, Washington
FIGURE NO.1MAY-2019
PROJECT NO.170292
BY:MWS / KES
REVISED BY:EAC
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SITE LOCATION
SITELOCATION
SITELOCATION
MW-02
MW-01
AB-02
AB-03
AB-04
AB-01B-1
B-5
B-2
B-4
B-3
AB-06
AB-05 AB-08
AB-07
EAST SIDE
STORMWATER
MANAGEMENT
FACILITY
WEST SIDE
STORMWATER
MANAGEMENT
FACILITY
CAD Path: Q:\King County\170383 Renton Shop\2019-05 Geotechnical Report-30 Percent\170383-02.dwg 11x17 Landscape || Date Saved: May 20, 2019 2:58pm || User: scuddGeotechnical Report - 30 Percent
King County Parks and Recreation Division - Renton Shop
3005 NE 4th Street
Renton, Washington
2
BY:MWS/SCC
Site and Exploration Plan
May-2019
REVISED BY:-PROJECT NO.170383
FIGURE NO.Feet
060120
Boring Location (Aspect)
Boring Location (King County)
Monitoring Well Location (Aspect)
Direct Push Probe Location (Aspect)
Legend
Source: Base map provided by King County
Department of Natural Resources and Parks, King
County Parks-Renton Shop, Draft 60%, 1/15/19.
Wellhead Protection Zone 2
West SideStormwaterManagementFacility
East SideStormwaterManagementFacility
Building SH
Building ST
Building CA
FIGURE NO.3MAY-2019
PROJECT NO.170292
BY:EAC / MW S
REVISED BY:- - -
Critical Areas MapGeotec hn ic a l Report - 30 Perc en tK in g Coun ty Pa rks a n d Rec rea tion Division – Ren ton Shop3005 N E 4th StreetRen ton , W a shin gton GIS Pa th: T:\projects_ 8\K in gCoun tyPa rksMa in ten a n ceFa cility_ 170383\Delivered\Geotechn ica lReport_ 30Percen t\03 Critica l Area s Ma p.m xd || Coordin a te System : NAD 1983 Sta tePla n e W a shin gton North FIPS 4601 Feet || Da te Sa ved: 5/20/2019 || User: ecrum b a ker || Prin t Da te: 5/20/2019
K in g Coun ty Pa rcel
Erosion Ha za rd - High
Slope City of Renton
>15% & <=25%
>25% & <=40% (Sen sitive)
>40% & <=90% (Protected)
>90% (Protected)
Wellhead Protection Area Zones
Zon e 1
Zon e 1 Modified
Zon e 2 0 200 400
Feet
Basemap Layer Credits || Pictometry, King County
APPENDIX A
Subsurface Explorations
ASPECT CONSULTING
PROJECT NO. 170383 - TASK 400 MAY 31, 2019 A-1
A. Subsurface Exploration Program
The field exploration programs consisted of drilling a total of drilling ten borings
(designated MW-01, MW-02, and AB-01 through AB-08) between March 2018 and
April 2019. Borings were advanced using sonic, hollow stem auger (HSA), and direct
push methods to between 15 feet and 75 feet bgs. The locations of the explorations are
shown on Figure 2 and the exploration logs are included in this appendix.
An Aspect geologist was present throughout the field exploration program to observe the
drilling procedure, assist in sampling, and to prepare descriptive logs of the exploration.
Soils were classified in general accordance with ASTM International (ASTM) D2488,
Standard Practice for Description and Identification of Soils (Visual-Manual Procedure).
The summary exploration logs represent our interpretation of the contents of the field log.
The stratigraphic contacts shown on the individual summary logs represent the
approximate boundaries between soil types; actual transitions may be more gradual. The
subsurface conditions depicted are only for the specific date and locations reported, and
therefore, are not necessarily representative of other locations and times.
A.1. Soil Borings
Two deep infiltration test well borings (designated MW-01 and MW-02) were drilled to
75 feet bgs with rotary sonic methods by Holocene Drilling using a track-mounted
Geoprobe 8140LC drill rig equipped with a 140-pound automatic-safety hammer.
Samples were obtained continuously below ground surface (bgs) to the depths explored.
Select samples were collected using the Standard Penetration Test (SPT) in general
accordance with ASTM D1586. The sampler types used are depicted on the exploration
logs in this appendix.
Four geotechnical borings (designated AB-01 through AB-04) were drilled to 26.5 feet
bgs with hollow stem augers by Gregory Drilling using a truck-mounted CME-75 drill rig
equipped with a 140-pound automatic-safety hammer. Samples were typically obtained at
2.5 feet to 5 feet intervals below ground surface (bgs) to the depths explored, using the
SPT in general accordance with ASTM D1586.
Four environment direct push probes (designated AB-05 through AB-08)were advanced
to between 15 and 20 feet bgs by Holt Services, Inc. with a Geoprobe 7822D. Samples
were collected continuously.
The SPT method involves driving a 2-inch-outside-diameter split-barrel sampler with a
140-pound hammer free-falling from a distance of 30 inches. The number of blows for
each 6-inch interval is recorded, and the number of blows required to drive the sampler
the final 12 inches is known as the Standard Penetration Resistance (“N”) or blow count.
The resistance, or N-value, provides a measure of the relative density of granular soils or
the relative consistency of cohesive soils. If a total of 50 blows are recorded for a single
6-inch interval, the test is terminated and the blow count is recorded as 50 blows for the
ASPECT CONSULTING
PROJECT NO. 170383 - TASK 400 MAY 31, 2019 A-2
total inches of penetration. Samples were placed in labeled plastic jars and taken to a
laboratory for further classification.
The geotechnical and environmental explorations were backfilled with the bentonite in
accordance with Washington State Department of Ecology guidelines. The deep
infiltration tests well borings were backfilled by cement grout from 25 to 75 feet bgs,
installing a 6-inch diameter monitoring well, and completing with a flush-mounted
monument.
AI Path: Q:\_ACAD Standards\FIELD REFERENCE\MASTERS\Exploration Log Key-2018.ai // user: jinman // last saved: 09/26/2018“WITH SILT” or “WITH CLAY” means 5 to 15% silt and clay, denoted by a “-“ in the group
name; e.g., SP-SM ● “SILTY” or “CLAYEY” means >15% silt and clay ● “WITH SAND” or “WITH
GRAVEL” means 15 to 30% sand and gravel. ● “SANDY” or “GRAVELLY” means >30% sand and
gravel. ● “Well-graded” means approximately equal amounts of fine to coarse grain sizes ● “Poorly
graded” means unequal amounts of grain sizes ● Group names separated by “/” means soil
contains layers of the two soil types; e.g., SM/ML.
Soils were described and identified in the field in general accordance with the methods described in
ASTM D2488. Where indicated in the log, soils were classified using ASTM D2487 or other
laboratory tests as appropriate. Refer to the report accompanying these exploration logs for details.
% by Weight
Density³SPT² Blows/Foot
HighlyOrganicSoilsFine-Grained Soils - 50%1 or More Passes No. 200 SieveCoarse-Grained Soils - More than 50%1 Retained on No. 200 SieveGravels - More than 50%1 of Coarse FractionRetained on No. 4 Sieve15% Fines5% FinesSands - 50%1 or More of Coarse FractionPasses No. 4 SieveSilts and ClaysLiquid Limit Less than 50%Silts and ClaysLiquid Limit 50% or More15% Fines5% FinesWell-graded GRAVEL
Well-graded GRAVEL WITH SAND
Poorly-graded GRAVEL
Poorly-graded GRAVEL WITH SAND
SILTY GRAVEL
SILTY GRAVEL WITH SAND
CLAYEY GRAVEL
CLAYEY GRAVEL WITH SAND
Well-graded SAND
Well-graded SAND WITH GRAVEL
Poorly-graded SAND
Poorly-graded SAND WITH GRAVEL
SILTY SAND
SILTY SAND WITH GRAVEL
CLAYEY SAND
CLAYEY SAND WITH GRAVEL
SILT
SANDY or GRAVELLY SILT
SILT WITH SAND
SILT WITH GRAVEL
LEAN CLAY
SANDY or GRAVELLY LEAN CLAY
LEAN CLAY WITH SAND
LEAN CLAY WITH GRAVEL
ORGANIC SILT
SANDY or GRAVELLY ORGANIC SILT
ORGANIC SILT WITH SAND
ORGANIC SILT WITH GRAVEL
ELASTIC SILT
SANDY or GRAVELLY ELASTIC SILT
ELASTIC SILT WITH SAND
ELASTIC SILT WITH GRAVEL
FAT CLAY
SANDY or GRAVELLY FAT CLAY
FAT CLAY WITH SAND
FAT CLAY WITH GRAVEL
ORGANIC CLAY
SANDY or GRAVELLY ORGANIC CLAY
ORGANIC CLAY WITH SAND
ORGANIC CLAY WITH GRAVEL
PEAT and other
mostly organic soils
GW
GP
GM
GC
SW
SP
SM
SC
ML
CL
OL
MH
CH
OH
PT
Modifier
Organic Chemicals
BTEX = Benzene, Toluene, Ethylbenzene, Xylenes
TPH-Dx = Diesel and Oil-Range Petroleum Hydrocarbons
TPH-G = Gasoline-Range Petroleum Hydrocarbons
VOCs = Volatile Organic Compounds
SVOCs = Semi-Volatile Organic Compounds
PAHs = Polycyclic Aromatic Hydrocarbon Compounds
PCBs = Polychlorinated Biphenyls
GEOTECHNICAL LAB TESTSMC = Natural Moisture Content
GS = Grain Size Distribution
FC = Fines Content (% < 0.075 mm)GH = Hydrometer TestAL = Atterberg Limits
C = Consolidation Test
Str = Strength Test
OC = Organic Content (% Loss by Ignition)
Comp = Proctor Test
K = Hydraulic Conductivity Test
SG = Specific Gravity Test
RCRA8 = As, Ba, Cd, Cr, Pb, Hg, Se, Ag, (d = dissolved, t = total)
MTCA5 = As, Cd, Cr, Hg, Pb (d = dissolved, t = total)
PP-13 = Ag, As, Be, Cd, Cr, Cu, Hg, Ni, Pb, Sb, Se, Tl, Zn (d=dissolved, t=total)
CHEMICAL LAB TESTS
PID = Photoionization Detector
Sheen = Oil Sheen Test
SPT 2 = Standard Penetration Test
NSPT = Non-Standard Penetration Test
DCPT = Dynamic Cone Penetration Test
<1 = Subtrace
1 to <5 = Trace
5 to 10 = Few
Dry = Absence of moisture, dusty, dry to the touch
Slightly Moist = Perceptible moisture
Moist = Damp but no visible water
Very Moist = Water visible but not free draining
Wet = Visible free water, usually from below water table
COMPONENT
DEFINITIONSDescriptive Term Size Range and Sieve Number
Boulders = Larger than 12 inches
Cobbles = 3 inches to 12 inches
Coarse Gravel = 3 inches to 3/4 inches
Fine Gravel = 3/4 inches to No. 4 (4.75 mm)
Coarse Sand = No. 4 (4.75 mm) to No. 10 (2.00 mm)
Medium Sand = No. 10 (2.00 mm) to No. 40 (0.425 mm)
Fine Sand = No. 40 (0.425 mm) to No. 200 (0.075 mm)
Silt and Clay = Smaller than No. 200 (0.075 mm)
Metals
ESTIMATED1
PERCENTAGE
MOISTURE
CONTENT
RELATIVE DENSITY
CONSISTENCY
GEOLOGIC CONTACTS
Very Loose = 0 to 4 ≥2'
Loose = 5 to 10 1' to 2'
Medium Dense = 11 to 30 3" to 1'
Dense = 31 to 50 1" to 3"
Very Dense = > 50 < 1"
Consistency³
Very Soft =0 to 1 Penetrated >1" easily by thumb. Extrudes between thumb & fingers.
Soft =2 to 4 Penetrated 1/4" to 1" easily by thumb. Easily molded.
Medium Stiff =5 to 8 Penetrated >1/4" with effort by thumb. Molded with strong pressure.
Stiff =9 to 15 Indented ~1/4" with effort by thumb.
Very Stiff =16 to 30 Indented easily by thumbnail.
Hard => 30 Indented with difficulty by thumbnail.
Non-Cohesive or Coarse-Grained Soils
SPT² Blows/Foot
Observed and Distinct Observed and Gradual Inferred
1. Estimated or measured percentage by dry weight
2. (SPT) Standard Penetration Test (ASTM D1586)
3. Determined by SPT, DCPT (ASTM STP399) or other field methods. See report text for details.
% by Weight Modifier
15 to 25 = Little
30 to 45 = Some
>50 = Mostly
Penetration with 1/2" Diameter Rod
Manual Test
FIELD TESTS
Cohesive or Fine-Grained Soils
Exploration Log Key
9
16
15
17
19
23
GS
CECOC=1.6%S-1Bulk 1S-2S-3S-4S-5S-612-inch-diameterflush-mountmonumentWell capped with acompression plug
VW Piezometerinstalled at 74.75 feetbgs, SN: 1907571
Cement grout
6-inch schedule 40PVC well casing
6-inch, 10-foot length,stainless steel V-wrapwire screen, 0.020-slot
6x9 Colorado silicasand filter pack
Threaded stainlesssteel cap
Cement grout
ASPHALT ASPHALT; (2 inches)
GRAVEL WITH SAND (GP); (4 inches)
FILL SAND WITH GRAVEL (SP); Medium dense, moist,brown; medium to coarse sand; fine to coarse, subangularto subrounded gravel.
GLACIAL OUTWASH DEPOSITS (Qpa) GRAVEL WITH SAND (GP); Medium dense to dense,moist, brown; medium to coarse sand; fine to coarse,subrounded gravel.
Grades to fine to coarse sand; fine to coarse, subroundedto rounded gravel; subrounded cobbles.
SILTY GRAVEL WITH SAND (GM); Dense, moist, brown
gray; fine to coarse sand; fine to coarse, subrounded
gravel.
GRAVEL (GP); Dense, moist, brown gray; few fine to
coarse sand; fine to coarse, subangular gravel.
Operator Work Start/Completion Dates
Blows/footWater Content (%)
MW-01Equipment
Legend
Contractor
320
315
310
305
300
MW-01
Tests
Geoprobe 8140LC
Sonic
Holocene Drilling
Exploration Method(s)
See Exploration Log Key for explanation
of symbols
Exploration Completionand Notes SampleType/ID
Depth to Water (Below GS)
Liquid Limit
Geotechnical Exploration Log
Water Level ATD
Logged by: DRTApproved by: MWS 05/30/2019
67.29' (Static)
Exploration Number
No Soil Sample Recovery
WaterLevelSheet 1 of 3
Depth(ft)
Sampling Method
4/15/2019 to 4/16/2019
Project Address & Site Specific Location
325' (est)
47.48666, -122.17937 (est)
Coordinates (Lat,Lon WGS84)
Plastic Limit
Description
5
10
15
20
25
3005 NE 4th St, Renton, Washington
ExplorationLog
NEW STANDARD EXPLORATION LOG TEMPLATE P:\GINTW\PROJECTS\KING COUNTY PARKS CFD 170383.GPJ May 31, 2019Top of Casing Elev. (NAVD88)
Blows/6"
5
10
15
20
25
Renton Shop Facility Design - 170383
Depth(feet)MaterialType
Ground Surface (GS) Elev. (NAVD88)
Zach Bailey
SampleTypeElev.(feet)
Static Water Level
324.75' (est)
Autohammer; 140 lb hammer; 30" drop
Continuous core 7" ID
Grab sample
Split Barrel 2" X 1.375" (SPT)
10 20 30 400 50
28
27
26
GSS-7S-8S-9S-10S-11S-12S-13VW Piezometerinstalled at 74.75 feetbgs, SN: 1907571
Cement grout
GRAVEL (GP); Dense, moist, brown gray; few fine tocoarse sand; fine to coarse, subangular gravel. (continued)
SAND WITH GRAVEL (SP); Dense, moist, brown;medium to coarse sand; little, fine, subangular tosubrounded gravel.
SILTY SAND (SM); Very dense, moist, brown;non-plastic silt; fine to medium sand.
Operator Work Start/Completion Dates
Blows/footWater Content (%)
MW-01Equipment
Legend
Contractor
290
285
280
275
270
MW-01
Tests
Geoprobe 8140LC
Sonic
Holocene Drilling
Exploration Method(s)
See Exploration Log Key for explanation
of symbols
Exploration Completionand Notes SampleType/ID
Depth to Water (Below GS)
Liquid Limit
Geotechnical Exploration Log
Water Level ATD
Logged by: DRTApproved by: MWS 05/30/2019
67.29' (Static)
Exploration Number
No Soil Sample Recovery
WaterLevelSheet 2 of 3
Depth(ft)
Sampling Method
4/15/2019 to 4/16/2019
Project Address & Site Specific Location
325' (est)
47.48666, -122.17937 (est)
Coordinates (Lat,Lon WGS84)
Plastic Limit
Description
35
40
45
50
55
3005 NE 4th St, Renton, Washington
ExplorationLog
NEW STANDARD EXPLORATION LOG TEMPLATE P:\GINTW\PROJECTS\KING COUNTY PARKS CFD 170383.GPJ May 31, 2019Top of Casing Elev. (NAVD88)
Blows/6"
35
40
45
50
55
Renton Shop Facility Design - 170383
Depth(feet)MaterialType
Ground Surface (GS) Elev. (NAVD88)
Zach Bailey
SampleTypeElev.(feet)
Static Water Level
324.75' (est)
Autohammer; 140 lb hammer; 30" drop
Continuous core 7" ID
Grab sample
Split Barrel 2" X 1.375" (SPT)
10 20 30 400 50
S-14S-15S-16Cement grout
6x9 Colorado silicasand filter pack
VW Piezometerinstalled at 74.75 feetbgs, SN: 1907571
SILTY SAND (SM); Very dense, moist, brown;non-plastic silt; fine to medium sand. (continued)
Grades to medium to coarse sand.
Bottom of exploration at 75 ft. bgs.
4/29/2019
4/16/2019
Operator Work Start/Completion Dates
Blows/footWater Content (%)
MW-01Equipment
Legend
Contractor
260
255
250
245
240
MW-01
Tests
Geoprobe 8140LC
Sonic
Holocene Drilling
Exploration Method(s)
See Exploration Log Key for explanation
of symbols
Exploration Completionand Notes SampleType/ID
Depth to Water (Below GS)
Liquid Limit
Geotechnical Exploration Log
Water Level ATD
Logged by: DRTApproved by: MWS 05/30/2019
67.29' (Static)
Exploration Number
No Soil Sample Recovery
WaterLevelSheet 3 of 3
Depth(ft)
Sampling Method
4/15/2019 to 4/16/2019
Project Address & Site Specific Location
325' (est)
47.48666, -122.17937 (est)
Coordinates (Lat,Lon WGS84)
Plastic Limit
Description
65
70
75
80
85
3005 NE 4th St, Renton, Washington
ExplorationLog
NEW STANDARD EXPLORATION LOG TEMPLATE P:\GINTW\PROJECTS\KING COUNTY PARKS CFD 170383.GPJ May 31, 2019Top of Casing Elev. (NAVD88)
Blows/6"
65
70
75
80
85
Renton Shop Facility Design - 170383
Depth(feet)MaterialType
Ground Surface (GS) Elev. (NAVD88)
Zach Bailey
SampleTypeElev.(feet)
Static Water Level
324.75' (est)
Autohammer; 140 lb hammer; 30" drop
Continuous core 7" ID
Grab sample
Split Barrel 2" X 1.375" (SPT)
10 20 30 400 50
9
22
24
5
17
29
GSS-1S-2S-3S-4S-5S-6S-7S-812-inch-diameterflush-mountmonumentWell capped with acompression plug
VW Piezometerinstalled at 74.6 feetbgs, SN: 1907570
Cement grout
6-inch schedule 40PVC well casing
6-inch, 10-foot length,stainless steel V-wrapwire screen, 0.020-slot
6x9 Colorado silicasand filter pack
Threaded stainlesssteel cap
Cement grout
GRAVEL WITH SAND (GP); (4 inches)
FILL GRAVEL WITH SAND (GP); Medium dense, moist, redbrown; medium to coarse sand; fine to coarse, subangularto subrounded gravel; subrounded to rounded cobbles;subtrace organics; burnt wood debris.
GLACIAL OUTWASH DEPOSITS (Qpa) GRAVEL WITH SAND (GW); Medium dense to dense,moist, brown gray; medium to coarse sand; fine to coarse,subangular to subrounded gravel; subrounded cobbles.
Grades gray, subrounded to rounded cobbles.
SAND WITH GRAVEL (SP); Dense, moist, gray; fine to
coarse sand; fine to coarse gravel; subrounded cobbles.
GRAVEL WITH SAND (GP); Dense, moist, brown gray;
coarse sand; fine to coarse, subrounded gravel.
Operator Work Start/Completion Dates
Blows/footWater Content (%)
MW-02Equipment
Legend
Contractor
320
315
310
305
300
MW-02
Tests
Geoprobe 8140LC
Sonic
Holocene Drilling
Exploration Method(s)
See Exploration Log Key for explanation
of symbols
Exploration Completionand Notes SampleType/ID
Depth to Water (Below GS)
Liquid Limit
Geotechnical Exploration Log
Water Level ATD
Logged by: DRTApproved by: MWS 05/30/2019
67.88' (Static)
Exploration Number
WaterLevelSheet 1 of 3
Depth(ft)
Sampling Method
4/17/2019 to 4/18/2019
Project Address & Site Specific Location
325' (est)
47.48659, -122.17802 (est)
Coordinates (Lat,Lon WGS84)
Plastic Limit
Description
5
10
15
20
25
3005 NE 4th St, Renton, Washington
ExplorationLog
NEW STANDARD EXPLORATION LOG TEMPLATE P:\GINTW\PROJECTS\KING COUNTY PARKS CFD 170383.GPJ May 31, 2019Top of Casing Elev. (NAVD88)
Blows/6"
5
10
15
20
25
Renton Shop Facility Design - 170383
Depth(feet)MaterialType
Ground Surface (GS) Elev. (NAVD88)
Zach Bailey
SampleTypeElev.(feet)
Static Water Level
324.75' (est)
Autohammer; 140 lb hammer; 30" drop
Continuous core 7" ID
Split Barrel 3" X 2.375" (Mod Cal)
10 20 30 400 50
25
23
19
CECOC=1%S-9S-10S-11S-12S-13S-14S-15VW Piezometerinstalled at 74.6 feetbgs, SN: 1907570
Cement Grout
GRAVEL WITH SAND (GP); Dense, moist, brown gray;coarse sand; fine to coarse, subrounded gravel.(continued)
GRAVELLY SILT WITH SAND (ML); Medium dense todense, moist, tan; fine sand, fine to coarse, subroundedgravel.
GRAVEL WITH SAND (GP); Medium dense to dense,moist, brown; coarse sand; fine to coarse, subroundedgravel.
SAND WITH GRAVEL (SP); Medium dense, moist, tan;fine sand; fine, subangular to subrounded gravel.
GRAVEL WITH SAND (GP); Medium dense, moist, gray;
medium to coarse sand; fine to coarse, subangular to
subrounded gravel.
Operator Work Start/Completion Dates
Blows/footWater Content (%)
MW-02Equipment
Legend
Contractor
290
285
280
275
270
MW-02
Tests
Geoprobe 8140LC
Sonic
Holocene Drilling
Exploration Method(s)
See Exploration Log Key for explanation
of symbols
Exploration Completionand Notes SampleType/ID
Depth to Water (Below GS)
Liquid Limit
Geotechnical Exploration Log
Water Level ATD
Logged by: DRTApproved by: MWS 05/30/2019
67.88' (Static)
Exploration Number
WaterLevelSheet 2 of 3
Depth(ft)
Sampling Method
4/17/2019 to 4/18/2019
Project Address & Site Specific Location
325' (est)
47.48659, -122.17802 (est)
Coordinates (Lat,Lon WGS84)
Plastic Limit
Description
35
40
45
50
55
3005 NE 4th St, Renton, Washington
ExplorationLog
NEW STANDARD EXPLORATION LOG TEMPLATE P:\GINTW\PROJECTS\KING COUNTY PARKS CFD 170383.GPJ May 31, 2019Top of Casing Elev. (NAVD88)
Blows/6"
35
40
45
50
55
Renton Shop Facility Design - 170383
Depth(feet)MaterialType
Ground Surface (GS) Elev. (NAVD88)
Zach Bailey
SampleTypeElev.(feet)
Static Water Level
324.75' (est)
Autohammer; 140 lb hammer; 30" drop
Continuous core 7" ID
Split Barrel 3" X 2.375" (Mod Cal)
10 20 30 400 50
S-16S-17S-18S-19Cement grout
6x9 Colorado silicasand filter pack
VW Piezometerinstalled at 74.6 feetbgs, SN: 1907570
GRAVEL WITH SAND (GP); Medium dense, moist, gray;medium to coarse sand; fine to coarse, subangular tosubrounded gravel. (continued)
SAND (SP); Medium dense, moist, brown; fine to coarsesand; few fine, subangular to subrounded gravel.
SAND WITH GRAVEL (SP); Medium dense, moist,brown; fine to coarse sand; fine, subangular to subroundedgravel.
SAND (SP); Medium dense, wet, brown; medium to
coarse sand.
Bottom of exploration at 76.5 ft. bgs.
4/29/2019
4/17/2019
Operator Work Start/Completion Dates
Blows/footWater Content (%)
MW-02Equipment
Legend
Contractor
260
255
250
245
240
MW-02
Tests
Geoprobe 8140LC
Sonic
Holocene Drilling
Exploration Method(s)
See Exploration Log Key for explanation
of symbols
Exploration Completionand Notes SampleType/ID
Depth to Water (Below GS)
Liquid Limit
Geotechnical Exploration Log
Water Level ATD
Logged by: DRTApproved by: MWS 05/30/2019
67.88' (Static)
Exploration Number
WaterLevelSheet 3 of 3
Depth(ft)
Sampling Method
4/17/2019 to 4/18/2019
Project Address & Site Specific Location
325' (est)
47.48659, -122.17802 (est)
Coordinates (Lat,Lon WGS84)
Plastic Limit
Description
65
70
75
80
85
3005 NE 4th St, Renton, Washington
ExplorationLog
NEW STANDARD EXPLORATION LOG TEMPLATE P:\GINTW\PROJECTS\KING COUNTY PARKS CFD 170383.GPJ May 31, 2019Top of Casing Elev. (NAVD88)
Blows/6"
65
70
75
80
85
Renton Shop Facility Design - 170383
Depth(feet)MaterialType
Ground Surface (GS) Elev. (NAVD88)
Zach Bailey
SampleTypeElev.(feet)
Static Water Level
324.75' (est)
Autohammer; 140 lb hammer; 30" drop
Continuous core 7" ID
Split Barrel 3" X 2.375" (Mod Cal)
10 20 30 400 50
16
17
16
11
12
11
7
10
14
14
21
17
11
15
14
14
15
18
7
14
13
GS
FC=4.1%
FC=8.2%S1S2S3S4S5S6S7Exploration backfilledwith 3/8-inch bentonitechips and capped withexcavated soil.
FILL SILTY SAND WITH GRAVEL (SM); medium dense,moist, orange-brown; fine to coarse sand; fine, rounded toangular gravel.
GLACIAL OUTWASH (Qpa) SAND WITH SILT AND GRAVEL (SP-SM); dense, moist,brown; fine and coarse sand; fine and coarse, subroundedto subangular gravel.
GRAVEL WITH SAND (GW); medium dense, moist,brown; fine to coarse sand; fine, subrounded to angulargravel.
Becomes fine and coarse, rounded to subangular gravel.
SAND WITH GRAVEL (SP); dense, moist, brown; fine tocoarse sand; fine and coarse, subrounded to subangulargravel.
Bottom of exploration at 26.5 ft. bgs.
Operator Work Start/Completion Dates
Blows/footWater Content (%)
AB-01Equipment
Legend
Contractor
325
320
315
310
305
AB-01
Tests
Truck-mounted CME75
Hollow-stem auger
Gregory Drilling
Exploration Method(s)
See Exploration Log Key for explanation
of symbols
Exploration Completionand Notes SampleType/ID
Depth to Water (Below GS)
Liquid Limit
Geotechnical Exploration Log
Logged by: JGFApproved by: MWS 05/30/2019
Exploration Number
No Soil Sample Recovery
WaterLevelSheet 1 of 1
Depth(ft)
Sampling Method
4/13/2018
Project Address & Site Specific Location
330' (est)
47.48642, -122.17887 (est)
Coordinates (Lat,Lon WGS84)
Plastic Limit
No Water Encountered
Description
5
10
15
20
25
3005 NE 4th St, Renton, Washington.
ExplorationLog
NEW STANDARD EXPLORATION LOG TEMPLATE P:\GINTW\PROJECTS\KING COUNTY PARKS CFD 170383.GPJ May 31, 2019Top of Casing Elev. (NAVD88)
Blows/6"
5
10
15
20
25
Renton Shop Facility Design - 170383
Depth(feet)MaterialType
Ground Surface (GS) Elev. (NAVD88)
Josh Willets
SampleTypeElev.(feet)
No Water Encountered
NA (est)
Autohammer; 140 lb hammer; 30" drop
Split Barrel 2" X 1.375" (SPT)
10 20 30 400 50
2
1
4
8
14
13
6
17
19
9
13
13
8
11
12
8
10
13
8
10
13
OC=3%
GS
FC=4.8%S1S2S3S4S5S6S7Exploration backfilledwith 3/8-inch bentonitechips and capped withexcavated soil.
FILL SILTY SAND WITH GRAVEL (SM); loose, moist,orange-brown; fine to coarse sand, fine, rounded toangular gravel.
GLACIAL OUTWASH DEPOSITS (Qpa) GRAVEL WITH SAND (GW); medium dense, moist,brown; fine to coarse sand, fine and coarse, subrounded toangular gravel.
Becomes dense, very moist, and gray at 7.5 bgs.
Becomes medium dense at 10' bgs.
Becomes moist at 15' bgs.
SAND WITH GRAVEL (SP); medium dense, moist,
brown; trace silt; fine to coarse sand; fine and coarse,
subrounded to angular gravel.
SAND (SP); medium dense, moist, brown; trace silt; fine
to coarse sand; fine, subrounded to angular gravel.
Bottom of exploration at 26.5 ft. bgs.
Operator Work Start/Completion Dates
Blows/footWater Content (%)
AB-02Equipment
Legend
Contractor
325
320
315
310
305
AB-02
Tests
Truck-mounted CME75
Hollow-stem auger
Gregory Drilling
Exploration Method(s)
See Exploration Log Key for explanation
of symbols
Exploration Completionand Notes SampleType/ID
Depth to Water (Below GS)
Liquid Limit
Geotechnical Exploration Log
Logged by: JGFApproved by: MWS 05/30/2019
Exploration Number
No Soil Sample Recovery
WaterLevelSheet 1 of 1
Depth(ft)
Sampling Method
4/13/2018
Project Address & Site Specific Location
330' (est)
47.48585, -122.17830 (est)
Coordinates (Lat,Lon WGS84)
Plastic Limit
No Water Encountered
Description
5
10
15
20
25
3005 NE 4th St, Renton, Washington.
ExplorationLog
NEW STANDARD EXPLORATION LOG TEMPLATE P:\GINTW\PROJECTS\KING COUNTY PARKS CFD 170383.GPJ May 31, 2019Top of Casing Elev. (NAVD88)
Blows/6"
5
10
15
20
25
Renton Shop Facility Design - 170383
Depth(feet)MaterialType
Ground Surface (GS) Elev. (NAVD88)
Josh Willets
SampleTypeElev.(feet)
No Water Encountered
NA (est)
Autohammer; 140 lb hammer; 30" drop
Split Barrel 2" X 1.375" (SPT)
10 20 30 400 50
8
13
9
8
12
18
8
13
14
10
13
15
12
18
19
10
12
13
13
22
15
OC=0.8%
GS
FC=5.3%S1S2S3S4S5S6S7Exploration backfilledwith 3/8-inch bentonitechips and capped withexcavated soil.
FILL SILTY SAND WITH GRAVEL (SM); loose, moist,orange-brown; fine to coarse sand; fine, rounded toangular gravel.
GLACIAL OUTWASH DEPOSITS (Qpa) SAND WITH GRAVEL (SP); medium dense, moist,brown; trace silt; fine to coarse sand; fine and coarse,rounded to subangular gravel.
GRAVEL WITH SAND (GW); dense, moist, brown, withcobbles; trace silt; fine to coarse sand; fine and coarse,rounded to subangular gravel.
SILTY SAND (SM); medium dense, brown, moist; fine tomedium sand.
SAND WITH SILT AND GRAVEL (SP-SM); mediumdense, brown, moist; fine to coarse sand; fine and coarse,subrounded to subangular gravel.
Becomes dense and very moist at 15' bgs.
SAND WITH SILT (SP-SM); medium dense, brown,
moist; fine to coarse sand; trace fine, subrounded to
subangular gravel.
SAND WITH SILT AND GRAVEL (SP-SM); dense,
brown, moist; fine to coarse sand; fine and coarse,
subrounded to subangular gravel.
Bottom of exploration at 26.5 ft. bgs.
Operator Work Start/Completion Dates
Blows/footWater Content (%)
AB-03Equipment
Legend
Contractor
325
320
315
310
305
AB-03
Tests
Truck-mounted CME75
Hollow-stem auger
Gregory Drilling
Exploration Method(s)
See Exploration Log Key for explanation
of symbols
Exploration Completionand Notes SampleType/ID
Depth to Water (Below GS)
Liquid Limit
Geotechnical Exploration Log
Logged by: JGFApproved by: MWS 05/30/2019
Exploration Number
No Soil Sample Recovery
WaterLevelSheet 1 of 1
Depth(ft)
Sampling Method
4/13/2018
Project Address & Site Specific Location
330' (est)
47.48606, -122.17942 (est)
Coordinates (Lat,Lon WGS84)
Plastic Limit
No Water Encountered
Description
5
10
15
20
25
3005 NE 4th St, Renton, Washington.
ExplorationLog
NEW STANDARD EXPLORATION LOG TEMPLATE P:\GINTW\PROJECTS\KING COUNTY PARKS CFD 170383.GPJ May 31, 2019Top of Casing Elev. (NAVD88)
Blows/6"
5
10
15
20
25
Renton Shop Facility Design - 170383
Depth(feet)MaterialType
Ground Surface (GS) Elev. (NAVD88)
Josh Willets
SampleTypeElev.(feet)
No Water Encountered
NA (est)
Autohammer; 140 lb hammer; 30" drop
Split Barrel 2" X 1.375" (SPT)
10 20 30 400 50
7
11
17
6
11
15
8
15
22
8
22
24
12
15
18
15
35
33
14
20
18
GS
FC=3.4%
FC=4.3%S1S2S3S4S5S6S7Exploration backfilledwith 3/8-inch bentonitechips and capped withexcavated soil.
FILL SILTY SAND WITH GRAVEL (SM); medium dense,moist, orange-brown; fine to coarse sand; fine, rounded toangular gravel.
GLACIAL OUTWASH DEPOSITS (Qpa) GRAVEL WITH SAND (GP); medium dense, moist,brown; fine to coarse sand; fine and coarse, subrounded tosubangular gravel.
SAND WITH GRAVEL (SP); medium dense, moist,brown; trace silt; fine to coarse sand; fine and coarse,subrounded to subangular gravel.
GRAVEL WITH SAND (GP); dense, moist, brown; fine tocoarse sand; fine and coarse, subrounded to subangulargravel.
SAND WITH GRAVEL (SP); dense, moist, brown; tracesilt; fine to coarse sand; fine and coarse, subrounded tosubangular gravel.
Becomes very dense at 20' bgs; blows elevated due to
gravel.
Becomes dense at 25' bgs.
Bottom of exploration at 26.5 ft. bgs.
Operator Work Start/Completion Dates
Blows/footWater Content (%)
AB-04Equipment
Legend
Contractor
325
320
315
310
305
AB-04
Tests
Truck-mounted CME75
Hollow-stem auger
Gregory Drilling
Exploration Method(s)
See Exploration Log Key for explanation
of symbols
Exploration Completionand Notes SampleType/ID
Depth to Water (Below GS)
Liquid Limit
Geotechnical Exploration Log
Logged by: JGFApproved by: MWS 05/30/2019
Exploration Number
No Soil Sample Recovery
WaterLevelSheet 1 of 1
Depth(ft)
Sampling Method
4/13/2018
Project Address & Site Specific Location
330' (est)
47.48637, -122.17945 (est)
Coordinates (Lat,Lon WGS84)
Plastic Limit
No Water Encountered
Description
5
10
15
20
25
3005 NE 4th St, Renton, Washington.
ExplorationLog
NEW STANDARD EXPLORATION LOG TEMPLATE P:\GINTW\PROJECTS\KING COUNTY PARKS CFD 170383.GPJ May 31, 2019Top of Casing Elev. (NAVD88)
Blows/6"
5
10
15
20
25
Renton Shop Facility Design - 170383
Depth(feet)MaterialType
Ground Surface (GS) Elev. (NAVD88)
Josh Willets
SampleTypeElev.(feet)
No Water Encountered
NA (est)
Autohammer; 140 lb hammer; 30" drop
Split Barrel 2" X 1.375" (SPT)
10 20 30 400 50
AB-01-12NWTPH-Dx,NWTPH-G
PID=0
Sheen=None
PID=0
Sheen=None
PID=0
Sheen=None
PID=0
Sheen=None
PID=0
Sheen=None
PID=0
Sheen=None
PID=0
PID=0
Sheen=None
PID=0
Sheen=None
PID=0
Sheen=None
Exploration backfilledwith 3/8-inch bentonitechips and capped withexcavated soil.Vacuum excavated to5 ft bgs
FILL SILTY GRAVEL WITH SAND (GM); wet to moist, brown;fine to coarse sand; rounded cobbles.
Becomes slightly moist.
GLACIAL OUTWASH DEPOSITS (Qpa) SAND WITH SILT AND GRAVEL (SW-SM); moist, gray;fine to coarse sand; fine to coarse gravel.
Bottom of exploration at 20 ft. bgs.
Operator Work Start/Completion Dates
AnalyticalSample Number &Lab Test(s)
AB-05Equipment
Legend
Contractor
325
320
315
310
305
AB-05
Field Tests
Geoprobe 7822D
Direct push
Holt Drilling
Exploration Method(s)
See Exploration Log Key for explanation
of symbols
Exploration Completionand Notes SampleType/ID
Depth to Water (Below GS)
Environmental Exploration Log
Logged by: MvApproved by: MWS 03/12/18
Exploration Number
No Soil Sample Recovery
WaterLevelSheet 1 of 1
Depth(ft)
Sampling Method
2/16/2018
Project Address & Site Specific Location
330' (est)
47.48615, -122.17895 (est)
Coordinates (Lat,Lon WGS84)
No Water Encountered
Description
5
10
15
20
25
3005 NE 4th St, Renton, SW corner of canopy
ExplorationLog
NEW STANDARD EXPLORATION LOG TEMPLATE P:\GINTW\PROJECTS\KING COUNTY PARKS CFD 170383.GPJ May 31, 2019Top of Casing Elev. (NAVD88)
5
10
15
20
25
Renton Shop Facility Design - 170383
Depth(feet)MaterialType
Ground Surface (GS) Elev. (NAVD88)
Mike
SampleTypeElev.(feet)
No Water Encountered
NA (est)
Percussion hammer
Continuous core 1.5" ID
Grab sample
AB-02-7NWTPH-Dx,NWTPH-G
PID=0
Sheen=None
PID=0
Sheen=None
PID=0
Sheen=None
PID=0
Sheen=None
PID=0
Sheen=None
PID=0
Sheen=None
PID=0
Sheen=None
PID=0
Sheen=None
PID=0
Exploration backfilledwith 3/8-inch bentonitechips and capped withexcavated soil.Vacuum excavated to5 ft bgs
FILL SILTY GRAVEL WITH SAND (GM); moist to wet, brown;fine to coarse sand; fine to coarse gravel; roundedcobbles.
Becomes slightly moist.
GLACIAL OUTWASH DEPOSITS (Qpa) SAND WITH SILT (SW-SM); moist, gray; fine to coarsesand; few percent gravel.
SAND WITH SILT (SP-SM); moist, gray; fine to medium
sand; few gravel.
Bottom of exploration at 20 ft. bgs.
Operator Work Start/Completion Dates
AnalyticalSample Number &Lab Test(s)
AB-06Equipment
Legend
Contractor
325
320
315
310
305
AB-06
Field Tests
Geoprobe 7822D
Direct push
Holt Drilling
Exploration Method(s)
See Exploration Log Key for explanation
of symbols
Exploration Completionand Notes SampleType/ID
Depth to Water (Below GS)
Environmental Exploration Log
Logged by: MvApproved by: MWS 03/12/18
Exploration Number
No Soil Sample Recovery
WaterLevelSheet 1 of 1
Depth(ft)
Sampling Method
2/16/2018
Project Address & Site Specific Location
330' (est)
47.48621, -122.17898 (est)
Coordinates (Lat,Lon WGS84)
No Water Encountered
Description
5
10
15
20
25
3005 NE 4th St, Renton, NW corner of canopy
ExplorationLog
NEW STANDARD EXPLORATION LOG TEMPLATE P:\GINTW\PROJECTS\KING COUNTY PARKS CFD 170383.GPJ May 31, 2019Top of Casing Elev. (NAVD88)
5
10
15
20
25
Renton Shop Facility Design - 170383
Depth(feet)MaterialType
Ground Surface (GS) Elev. (NAVD88)
Mike
SampleTypeElev.(feet)
No Water Encountered
NA (est)
Percussion hammer
Continuous core 1.5" ID
Grab sample
AB-03-12NWTPH-Dx,NWTPH-G
PID=0
Sheen=None
PID=0
Sheen=None
PID=0
Sheen=None
PID=0
Sheen=None
PID=0
Sheen=None
PID=0
Sheen=None
PID=0
Sheen=None
PID=0
Exploration backfilledwith 3/8-inch bentonitechips and capped withexcavated soil.Vacuum excavated to5 ft bgs
FILL SILTY GRAVEL WITH SAND (GM); wet to moist, brown;fine to coarse gravel; fine to coarse sand
GLACIAL OUTWASH DEPOSITS (Qpa) SAND WITH SILT (SW-SM); moist, gray; fine to coarsesand; few gravel.
Bottom of exploration at 15 ft. bgs.
Operator Work Start/Completion Dates
AnalyticalSample Number &Lab Test(s)
AB-07Equipment
Legend
Contractor
325
320
315
310
305
AB-07
Field Tests
Geoprobe 7822D
Direct push
Holt Drilling
Exploration Method(s)
See Exploration Log Key for explanation
of symbols
Exploration Completionand Notes SampleType/ID
Depth to Water (Below GS)
Environmental Exploration Log
Logged by: MvApproved by: MWS 03/12/18
Exploration Number
No Soil Sample Recovery
WaterLevelSheet 1 of 1
Depth(ft)
Sampling Method
2/16/2018
Project Address & Site Specific Location
330' (est)
47.48620, -122.17884 (est)
Coordinates (Lat,Lon WGS84)
No Water Encountered
Description
5
10
15
20
25
3005 NE 4th St, Renton, NE corner of canopy
ExplorationLog
NEW STANDARD EXPLORATION LOG TEMPLATE P:\GINTW\PROJECTS\KING COUNTY PARKS CFD 170383.GPJ May 31, 2019Top of Casing Elev. (NAVD88)
5
10
15
20
25
Renton Shop Facility Design - 170383
Depth(feet)MaterialType
Ground Surface (GS) Elev. (NAVD88)
Mike
SampleTypeElev.(feet)
No Water Encountered
NA (est)
Percussion hammer
Continuous core 1.5" ID
Grab sample
AB-04-12NWTPH-Dx,NWTPH-G
PID=0
Sheen=None
PID=0
Sheen=None
PID=0
Sheen=None
PID=0
Sheen=None
PID=0
Sheen=None
PID=0
Sheen=None
PID=0
Sheen=None
PID=0
Sheen=None
PID=0
Sheen=None
Exploration backfilledwith 3/8-inch bentonitechips and capped withexcavated soil.Vacuum excavated to5 ft bgs
FILL SILTY GRAVEL WITH SAND (GM); wet to moist, brown;fine to coarse sand; fine to coarse gravel; containsconstruction debris.
Becomes slighlty moist; becomes gray, tan, brown
GLACIAL OUTWASH DEPOSITS (Qpa) SAND WITH SILT (SW-SM); moist, gray; fine to coarsesand; few gravel.
Bottom of exploration at 15 ft. bgs.
Operator Work Start/Completion Dates
AnalyticalSample Number &Lab Test(s)
AB-08Equipment
Legend
Contractor
325
320
315
310
305
AB-08
Field Tests
Geoprobe 7822D
Direct push
Holt Drilling
Exploration Method(s)
See Exploration Log Key for explanation
of symbols
Exploration Completionand Notes SampleType/ID
Depth to Water (Below GS)
Environmental Exploration Log
Logged by: MvApproved by: MWS 03/12/18
Exploration Number
No Soil Sample Recovery
WaterLevelSheet 1 of 1
Depth(ft)
Sampling Method
2/16/2018
Project Address & Site Specific Location
330' (est)
47.48618, -122.17884 (est)
Coordinates (Lat,Lon WGS84)
No Water Encountered
Description
5
10
15
20
25
3005 NE 4th St, Renton, SE corner of canopy
ExplorationLog
NEW STANDARD EXPLORATION LOG TEMPLATE P:\GINTW\PROJECTS\KING COUNTY PARKS CFD 170383.GPJ May 31, 2019Top of Casing Elev. (NAVD88)
5
10
15
20
25
Renton Shop Facility Design - 170383
Depth(feet)MaterialType
Ground Surface (GS) Elev. (NAVD88)
Mike
SampleTypeElev.(feet)
No Water Encountered
NA (est)
Percussion hammer
Continuous core 1.5" ID
Grab sample
APPENDIX B
Laboratory Test Results
ASPECT CONSULTING
PROJECT NO. 170383 - TASK 400 MAY 31, 2019 B-1
B.Laboratory Test Results
A laboratory testing program was developed to determine index and engineering
properties of materials and to determine the concentrations of potential contaminants at
the Site. Soil samples used in the testing program were collected from the soil borings.
The tests performed and the procedures followed are outlined below.
B.1. Soil Classification
Soil samples from the explorations were visually classified in the field and then taken to
our office where the classifications were verified in a relatively controlled environment.
Field and laboratory observations include density/consistency, moisture condition, and
grain-size and plasticity estimates. The classifications of selected samples were checked
by grain-size analysis and plasticity index testing. Classifications were made in general
accordance with the Unified Soil Classification System (USCS), ASTM D2488.
B.2. Moisture-Content Determination
Moisture contents were determined for samples recovered in the explorations in general
accordance with ASTM D2216, as soon as possible following their arrival to the
laboratory. Moisture contents are shown on the exploration logs and shown in this
appendix. Water content determination was also completed as part of other tests
conducted and is shown with the results of those tests.
B.3. Grain-Size Analyses
Grain-size analysis was conducted in accordance with ASTM D6913 on selected soil
samples collected from the soil borings. The results of the tests are presented in this
appendix, plotting percent finer by weight versus grain size and on the boring logs.
B.4. Organic Content
Organic contents of select samples were tested in general accordance with ASTM D 2974
in a muffle furnace. The organic content is the percentage by weight of oven-dried
organic matter (pre-burn dry weight minus post-burn dry weight) divided by the total
oven-dried sample weight. The results of the tests are presented in this appendix.
B.5. Cation Exchange Capacity
The cation exchange capacity (CEC) is the exchangeable cations that a soil can adsorb.
Units are milliequivalents per 100 grams of soil. Soils with a CEC of 5 milliequivalents at
pH 7 will have a CEC less than 5 milliequivalents when the pH is less 7. The CEC of the
treatment soil must be equal to or greater than 5 milliequivalents per100 grams dry soil
per USEPA Method 9081. The results of the tests are presented in this appendix.
ASPECT CONSULTING
PROJECT NO. 170383 - TASK 400 MAY 31, 2019 B-2
B.6. Analytical Tests
One soil sample from each of the four direct-push explorations were submitted to an
accredited analytical laboratory for detection and quantification of contamination. The
selected samples were collected at a depth at or below the presumed bottom of the USTs.
Samples were collected in general conformance with EPA Method 5030 and with
applicable industry practices.
The laboratory analyzed each sample for gasoline-range organics (by method NWTPH-
G) and diesel- and oil-range organics (method NWTPH-Dx). The laboratory report is
included in this appendix.
Test(s) Performed:Test(s) Performed:
X
X
Respectfully Submitted,
Laboratory Technician
Atterberg Limits
Moisture Content Cation Exchange Capacity
Specific Gravity, Coarse
Specific Gravity, Fine
Hydrometer Analysis
Proctor
Sand Equivalent
Fracture Count Organic Content
WSDOT Degradation
Bulk Density & Voids
Corporate ~ 777 Chrysler Drive • Burlington, WA 98233 • Phone (360) 755-1990 • Fax (360) 755-1980
Regional Offices: Olympia ~ 360.534.9777 Bellingham ~ 360.647.6061 Silverdale ~ 360.698.6787 Tukwila ~ 206.241.1974
Visit our website: www.mtc-inc.net
Meghan Blodgett-Carrillo
If you have any questions concerning the test results, the procedures used, or if we can be of any further assistance please call on us at the
number below.
See Report
See Reports
Materials Testing & Consulting, Inc.
Geotechnical Engineering • Special Inspection • Materials Testing • Environmental Consulting
Test Results
Seattle, WA 98104
Dustin Taylor
May 10, 2019
18B011-16
B19-0284 & 0285
Project #:
Parks Central MaintenanceAddress:
As requested MTC, Inc. has performed the following test(s) on the sample referenced above. The testing was performed in accordance with
current applicable AASHTO or ASTM standards as indicated below. The results obtained in our laboratory were as follows below or on the
attached pages:
Test Results
Client:
Sample #:
Date:
Project:
Aspect Consulting
710 2nd Ave., Suite 550
Attn:
Sulfate SoundnessSieve Analysis
Revised on:Date sampled:April 15, 2019
Project:Parks Central Maintenance Client:
Project #:18B011-16
Date Received:May 3, 2019 Sampled by:
Date Tested:May 7, 2019 Tested by:
Sample #Location Tare Wet + Tare Dry + Tare Wgt. Of Moisture Wgt. Of Soil % Moisture
B19-0284 MW-01 Bulk 2 @ 20'718.8 3855.8 3817.4 38.4 3098.6 1.2%
B19-0285 MW-02 Bulk 7 @ 35'763.6 3257.3 3201.5 55.8 2437.9 2.3%
0.0 0.0 #DIV/0!
0.0 0.0 #DIV/0!
0.0 0.0 #DIV/0!
0.0 0.0 #DIV/0!
0.0 0.0 #DIV/0!
0.0 0.0 #DIV/0!
0.0 0.0 #DIV/0!
0.0 0.0 #DIV/0!
Sample #Location Tare % Organics
B19-0284 MW-01 Bulk 2 @ 20'68.1 1.6%
B19-0285 MW-02 Bulk 7 @ 35'68.6 1.0%
#DIV/0!
#DIV/0!
#DIV/0!
#DIV/0!
#DIV/0!
#DIV/0!
#DIV/0!
#DIV/0!
Reviewed by:
Meghan Blodgett-Carrillo
Visit our website: www.mtc-inc.net
All results apply only to actual locations and materials tested. As a mutual protection to clients, the public and ourselves, all reports are submitted as the confidential property of clients, and authorization for publication of statements, conclusions or extracts from or regarding our reports
is reserved pending our written approval.
Materials Testing & Consulting, Inc.
Geotechnical Engineering • Special Inspection • Materials Testing • Environmental Consulting
106.8 106.2
Moisture Content - AASHTO T-265
Organic Content - AASHTO T-267
Soil + Tare, Pre-Ignition Soil + Tare, Post Ignition
Aspect Consulting
Client
Corporate ~ 777 Chrysler Drive • Burlington, WA 98233 • Phone (360) 755-1990 • Fax (360) 755-1980
Regional Offices: Olympia ~ 360.534.9777 Bellingham ~ 360.647.6111 Silverdale ~ 360.698.6787 Tukwila ~ 206.241.1974
A. Eifrig
108.2 107.8
MATERIALS TESTING
777 CHRYSLER DR
Burlington , WA 98233
5/6/2019
Soil
PARKS CENTRAL MAINTENANCE
B19-0284 MW-01 BULK 2 AT 20FT
S19-06743
Date Received:
Grower:
Sampled By:
Field:
Laboratory #:
Test Results
Customer Account #:
Customer Sample ID:
Other Tests:
Cation Exchange meq/100gCEC 4.2 pH 1:1
E.C. 1:1 m.mhos/cm
Est Sat Paste E.C. m.mhos/cm
Effervescence
Lbs/Acre
Ammonium - N mg/kg
%Organic Matter W.B.ENR:
This is your Invoice #:B.Thyssen, CPReviewed by:S19-06743 Account #234500
We make every effort to provide an accurate analysis of your sample. For reasonable cause we will repeat tests, but because of factors beyond our control
in sampling procedures and the inherent variability of soil, our liability is limited to the price of the tests. Recommendations are to be used as general
guides and should be modified for specific field conditions and situations. Note: "u" indicates that the element was analyzed for but not detected
MATERIALS TESTING
777 CHRYSLER DR
Burlington , WA 98233
5/6/2019
Soil
PARKS CENTRAL MAINTENANCE
B19-0285 MW-02 BULK 7 AT 35 FT
S19-06744
Date Received:
Grower:
Sampled By:
Field:
Laboratory #:
Test Results
Customer Account #:
Customer Sample ID:
Other Tests:
Cation Exchange meq/100gCEC 5.0 pH 1:1
E.C. 1:1 m.mhos/cm
Est Sat Paste E.C. m.mhos/cm
Effervescence
Lbs/Acre
Ammonium - N mg/kg
%Organic Matter W.B.ENR:
This is your Invoice #:B.Thyssen, CPReviewed by:S19-06744 Account #234500
We make every effort to provide an accurate analysis of your sample. For reasonable cause we will repeat tests, but because of factors beyond our control
in sampling procedures and the inherent variability of soil, our liability is limited to the price of the tests. Recommendations are to be used as general
guides and should be modified for specific field conditions and situations. Note: "u" indicates that the element was analyzed for but not detected
FRIEDMAN & BRUYA, INC.
_________________________________________________
ENVIRONMENTAL CHEMISTS
James E. Bruya, Ph.D. 3012 16th Avenue West
Yelena Aravkina, M.S. Seattle, WA 98119-2029
Michael Erdahl, B.S. (206) 285-8282
Arina Podnozova, B.S. fbi@isomedia.com
Eric Young, B.S. www.friedmanandbruya.com
February 22, 2018
Matthew Vonder-Ahe, Project Manager
Aspect Consulting, LLC
350 Madison Ave. N.
Bainbridge Island, WA 98110-1810
Dear Mr Vonder-Ahe:
Included are the results from the testing of material submitted on February 16, 2018
from the KCPCFM 170383, F&BI 802285 project. There are 6 pages included in this
report. Any samples that may remain are currently scheduled for disposal in 30 days. If
you would like us to return your samples or arrange for long term storage at our offices,
please contact us as soon as possible.
We appreciate this opportunity to be of service to you and hope you will call if you have
any questions.
Sincerely,
FRIEDMAN & BRUYA, INC.
Michael Erdahl
Project Manager
Enclosu res
c: data@aspectconsulting.com
ASP0222R.DOC
FRIEDMAN & BRUYA, INC.
_________________________________________________
ENVIRONMENTAL CHEMISTS
1
CASE NARRATIVE
This case narrative encompasses samples received on February 16, 2018 by Friedman &
Bruya, Inc. from the Aspect Consulting, LLC KCPCFM 170383, F&BI 802285 project.
Samples were logged in under the laboratory ID’s listed below.
Laboratory ID Aspect Consulting, LLC
802285 -01 AB-02-7
802285 -02 AB-01-12
802285 -03 AB-03-12
802285 -04 AB-04-12
802285 -05 Trip Blank
All quality control requirements were acceptable.
FRIEDMAN & BRUYA, INC.
_________________________________________________
ENVIRONMENTAL CHEMISTS
2
Date of Report: 02/22/18
Date Received: 02/16/18
Project: KCPCFM 170383, F&BI 802285
Date Extracted: 02/20/18
Date Analyzed: 02/20/18
RESULTS FROM THE ANALYSIS OF SOIL SAMPLES
FOR TOTAL PETROLEUM HYDROCARBONS AS GASOLINE
USING METHOD NWTPH-Gx
Results Reported on a Dry Weight Basis
Results Reported as mg/kg (ppm)
Surrogate
Sample ID Gasoline Range (% Recovery )
Laboratory ID (Limit 58-139)
AB-02-7 <5 99
802285-01
AB-01-12 <5 97
802285-02
AB-03-12 <5 98
802285-03
AB-04-12 <5 95
802285-04
Method Blank <5 95
08-340 MB2
FRIEDMAN & BRUYA, INC.
_________________________________________________
ENVIRONMENTAL CHEMISTS
3
Date of Report: 02/22/18
Date Received: 02/16/18
Project: KCPCFM 170383, F&BI 802285
Date Extracted: 02/19/18
Date Analyzed: 02/19/18
RESULTS FROM THE ANALYSIS OF SOIL SAMPLES
FOR TOTAL PETROLEUM HYDROCARBONS AS
DIESEL AND MOTOR OIL
USING METHOD NWTPH-Dx
Results Reported on a Dry Weight Basis
Results Reported as mg/kg (ppm)
Surrogate
Sample ID Diesel Range Motor Oil Range (% Recovery)
Laboratory ID (C10-C25) (C25-C36) (Limit 48-168)
AB-02-7 <50 <250 101
802285-01
AB-01-12 <50 <250 97
802285-02
AB-03-12 <50 <250 108
802285-03
AB-04-12 <50 <250 109
802285-04
Method Blank <50 <250 101
08-375 MB
FRIEDMAN & BRUYA, INC.
_________________________________________________
ENVIRONMENTAL CHEMISTS
4
Date of Report: 02/22/18
Date Received: 02/16/18
Project: KCPCFM 170383, F&BI 802285
QUALITY ASSURANCE RESULTS FOR THE ANALYSIS OF SOIL SAMPLES
FOR TPH AS GASOLINE
USING METHOD NWTPH-Gx
Laboratory Code: 802300-01 (Duplicate)
Analyte
Reporting Units
Sample Result
(Wet Wt)
Duplicate
Result
(Wet Wt)
RPD
(Limit 20)
Gasoline mg/kg (ppm) <5 <5 nm
Laboratory Code: Laboratory Control Sample
Analyte
Reporting Units
Spike
Level
Percent
Recovery
LCS
Acceptance
Criteria
Gasoline mg/kg (ppm) 20 95 71-131
FRIEDMAN & BRUYA, INC.
_________________________________________________
ENVIRONMENTAL CHEMISTS
5
Date of Report: 02/22/18
Date Received: 02/16/18
Project: KCPCFM 170383, F&BI 802285
QUALITY ASSURANCE RESULTS FROM THE ANALYSIS OF SOIL
SAMPLES
FOR TOTAL PETROLEUM HYDROCARBONS AS
DIESEL EXTENDED USING METHOD NWTPH-Dx
Laboratory Code: 802289-01 (Matrix Spike)
Analyte
Reporting
Units
Spike
Level
Sample
Result
(Wet Wt)
Percent
Recovery
MS
Percent
Recovery
MSD
Acceptance
Criteria
RPD
(Limit 20)
Diesel Extended mg/kg (ppm) 5,000 <50 90 94 73-135 4
Laboratory Code: Laboratory Control Sample
Analyte
Reporting Units
Spike
Level
Percent
Recovery
LCS
Acceptance
Criteria
Diesel Extended mg/kg (ppm) 5,000 80 74-139
FRIEDMAN & BRUYA, INC.
_________________________________________________
ENVIRONMENTAL CHEMISTS
6
Data Qualifiers & Definitions a - The analyte was detected at a level less than five times the reporting limit. The RPD results may not provide reliable information on the variability of the analysis.
b - The analyte was spiked at a level that was less than five times that present in the sample. Matrix spike recoveries may not be meaningful.
ca - The calibration results for the analyte were outside of acceptance criteria. The value reported is an estimate.
c - The presence of the analyte may be due to carryover from previous sample injections.
cf - The sample was centrifuged prior to analysis.
d - The sample was diluted. Detection limits were raised and surrogate recoveries may not be meaningful.
dv - Insufficient sample volume was available to achieve normal reporting limits.
f - The sample was laboratory filtered prior to analysis.
fb - The analyte was detected in the method blank.
fc - The compound is a common laboratory and field contaminant.
hr - The sample and duplicate were reextracted and reanalyzed. RPD results were still outside of control limits. Variability is attributed to sample inhomogeneity.
hs - Headspace was present in the container used for analysis.
ht – The analysis was performed outside the method or client-specified holding time requirement.
ip - Recovery fell outside of control limits. Compounds in the sample matrix interfered with the quantitation of the analyte.
j - The analyte concentration is reported below the lowest calibration standard. The value reported is an estimate.
J - The internal standard associated with the analyte is out of control limits. The reported concentration is an estimate.
jl - The laboratory control sample(s) percent recovery and/or RPD were out of control limits. The reported concentration should be considered an estimate. js - The surrogate associated with the analyte is out of control limits. The reported concentration should be considered an estimate.
lc - The presence of the analyte is likely due to laboratory contamination.
L - The reported concentration was generated from a library search.
nm - The analyte was not detected in one or more of the duplicate analyses. Therefore, calculation of the RPD is not applicable.
pc - The sample was received with incorrect preservation or in a container not approved by the method. The value reported should be considered an estimate. ve - The analyte response exceeded the valid instrument calibration range. The value reported is an estimate.
vo - The value reported fell outside the control limits established for this analyte.
x - The sample chromatographic pattern does not resemble the fuel standard used for quantitation.
FIGURE B1
FIGURE B2
FIGURE B3
FIGURE B4
FIGURE B5
FIGURE B6
Test(s) Performed:Test(s) Performed:
X
X
Respectfully Submitted,
Laboratory Technician
Atterberg Limits
Moisture Content Cation Exchange Capacity
Specific Gravity, Coarse
Specific Gravity, Fine
Hydrometer Analysis
Proctor
Sand Equivalent
Fracture Count Organic Content
WSDOT Degradation
Bulk Density & Voids
Corporate ~ 777 Chrysler Drive • Burlington, WA 98233 • Phone (360) 755-1990 • Fax (360) 755-1980
Regional Offices: Olympia ~ 360.534.9777 Bellingham ~ 360.647.6061 Silverdale ~ 360.698.6787 Tukwila ~ 206.241.1974
Visit our website: www.mtc-inc.net
Meghan Blodgett-Carrillo
If you have any questions concerning the test results, the procedures used, or if we can be of any further assistance please call on us at the
number below.
See Report
See Reports
Materials Testing & Consulting, Inc.
Geotechnical Engineering • Special Inspection • Materials Testing • Environmental Consulting
Test Results
Seattle, WA 98104
Dustin Taylor
May 10, 2019
18B011-16
B19-0284 & 0285
Project #:
Parks Central MaintenanceAddress:
As requested MTC, Inc. has performed the following test(s) on the sample referenced above. The testing was performed in accordance with
current applicable AASHTO or ASTM standards as indicated below. The results obtained in our laboratory were as follows below or on the
attached pages:
Test Results
Client:
Sample #:
Date:
Project:
Aspect Consulting
710 2nd Ave., Suite 550
Attn:
Sulfate SoundnessSieve Analysis
Revised on:Date sampled:April 15, 2019
FIGURE B7
Project:Parks Central Maintenance Client:
Project #:18B011-16
Date Received:May 3, 2019 Sampled by:
Date Tested:May 7, 2019 Tested by:
Sample #Location Tare Wet + Tare Dry + Tare Wgt. Of Moisture Wgt. Of Soil % Moisture
B19-0284 MW-01 Bulk 2 @ 20'718.8 3855.8 3817.4 38.4 3098.6 1.2%
B19-0285 MW-02 Bulk 7 @ 35'763.6 3257.3 3201.5 55.8 2437.9 2.3%
0.0 0.0 #DIV/0!
0.0 0.0 #DIV/0!
0.0 0.0 #DIV/0!
0.0 0.0 #DIV/0!
0.0 0.0 #DIV/0!
0.0 0.0 #DIV/0!
0.0 0.0 #DIV/0!
0.0 0.0 #DIV/0!
Sample #Location Tare % Organics
B19-0284 MW-01 Bulk 2 @ 20'68.1 1.6%
B19-0285 MW-02 Bulk 7 @ 35'68.6 1.0%
#DIV/0!
#DIV/0!
#DIV/0!
#DIV/0!
#DIV/0!
#DIV/0!
#DIV/0!
#DIV/0!
Reviewed by:
Meghan Blodgett-Carrillo
Visit our website: www.mtc-inc.net
All results apply only to actual locations and materials tested. As a mutual protection to clients, the public and ourselves, all reports are submitted as the confidential property of clients, and authorization for publication of statements, conclusions or extracts from or regarding our reports
is reserved pending our written approval.
Materials Testing & Consulting, Inc.
Geotechnical Engineering • Special Inspection • Materials Testing • Environmental Consulting
106.8 106.2
Moisture Content - AASHTO T-265
Organic Content - AASHTO T-267
Soil + Tare, Pre-Ignition Soil + Tare, Post Ignition
Aspect Consulting
Client
Corporate ~ 777 Chrysler Drive • Burlington, WA 98233 • Phone (360) 755-1990 • Fax (360) 755-1980
Regional Offices: Olympia ~ 360.534.9777 Bellingham ~ 360.647.6111 Silverdale ~ 360.698.6787 Tukwila ~ 206.241.1974
A. Eifrig
108.2 107.8
FIGURE B8
MATERIALS TESTING
777 CHRYSLER DR
Burlington , WA 98233
5/6/2019
Soil
PARKS CENTRAL MAINTENANCE
B19-0284 MW-01 BULK 2 AT 20FT
S19-06743
Date Received:
Grower:
Sampled By:
Field:
Laboratory #:
Test Results
Customer Account #:
Customer Sample ID:
Other Tests:
Cation Exchange meq/100gCEC 4.2 pH 1:1
E.C. 1:1 m.mhos/cm
Est Sat Paste E.C. m.mhos/cm
Effervescence
Lbs/Acre
Ammonium - N mg/kg
%Organic Matter W.B.ENR:
This is your Invoice #:B.Thyssen, CPReviewed by:S19-06743 Account #234500
We make every effort to provide an accurate analysis of your sample. For reasonable cause we will repeat tests, but because of factors beyond our control
in sampling procedures and the inherent variability of soil, our liability is limited to the price of the tests. Recommendations are to be used as general
guides and should be modified for specific field conditions and situations. Note: "u" indicates that the element was analyzed for but not detected
FIGURE B9
MATERIALS TESTING
777 CHRYSLER DR
Burlington , WA 98233
5/6/2019
Soil
PARKS CENTRAL MAINTENANCE
B19-0285 MW-02 BULK 7 AT 35 FT
S19-06744
Date Received:
Grower:
Sampled By:
Field:
Laboratory #:
Test Results
Customer Account #:
Customer Sample ID:
Other Tests:
Cation Exchange meq/100gCEC 5.0 pH 1:1
E.C. 1:1 m.mhos/cm
Est Sat Paste E.C. m.mhos/cm
Effervescence
Lbs/Acre
Ammonium - N mg/kg
%Organic Matter W.B.ENR:
This is your Invoice #:B.Thyssen, CPReviewed by:S19-06744 Account #234500
We make every effort to provide an accurate analysis of your sample. For reasonable cause we will repeat tests, but because of factors beyond our control
in sampling procedures and the inherent variability of soil, our liability is limited to the price of the tests. Recommendations are to be used as general
guides and should be modified for specific field conditions and situations. Note: "u" indicates that the element was analyzed for but not detected
FIGURE B10
FIGURE B11
FIGURE B12
FIGURE B13
FIGURE B14
FIGURE B15
FIGURE B16
FIGURE B17
FIGURE B18
FIGURE B19
FIGURE B20
FIGURE B21
FIGURE B22
FRIEDMAN & BRUYA, INC.
_________________________________________________
ENVIRONMENTAL CHEMISTS
James E. Bruya, Ph.D. 3012 16th Avenue West
Yelena Aravkina, M.S. Seattle, WA 98119-2029
Michael Erdahl, B.S. (206) 285-8282
Arina Podnozova, B.S. fbi@isomedia.com
Eric Young, B.S. www.friedmanandbruya.com
February 22, 2018
Matthew Vonder-Ahe, Project Manager
Aspect Consulting, LLC
350 Madison Ave. N.
Bainbridge Island, WA 98110-1810
Dear Mr Vonder-Ahe:
Included are the results from the testing of material submitted on February 16, 2018
from the KCPCFM 170383, F&BI 802285 project. There are 6 pages included in this
report. Any samples that may remain are currently scheduled for disposal in 30 days. If
you would like us to return your samples or arrange for long term storage at our offices,
please contact us as soon as possible.
We appreciate this opportunity to be of service to you and hope you will call if you have
any questions.
Sincerely,
FRIEDMAN & BRUYA, INC.
Michael Erdahl
Project Manager
Enclosu res
c: data@aspectconsulting.com
ASP0222R.DOC
FIGURE B23
FRIEDMAN & BRUYA, INC.
_________________________________________________
ENVIRONMENTAL CHEMISTS
1
CASE NARRATIVE
This case narrative encompasses samples received on February 16, 2018 by Friedman &
Bruya, Inc. from the Aspect Consulting, LLC KCPCFM 170383, F&BI 802285 project.
Samples were logged in under the laboratory ID’s listed below.
Laboratory ID Aspect Consulting, LLC
802285 -01 AB-02-7
802285 -02 AB-01-12
802285 -03 AB-03-12
802285 -04 AB-04-12
802285 -05 Trip Blank
All quality control requirements were acceptable.
FIGURE B24
FRIEDMAN & BRUYA, INC.
_________________________________________________
ENVIRONMENTAL CHEMISTS
2
Date of Report: 02/22/18
Date Received: 02/16/18
Project: KCPCFM 170383, F&BI 802285
Date Extracted: 02/20/18
Date Analyzed: 02/20/18
RESULTS FROM THE ANALYSIS OF SOIL SAMPLES
FOR TOTAL PETROLEUM HYDROCARBONS AS GASOLINE
USING METHOD NWTPH-Gx
Results Reported on a Dry Weight Basis
Results Reported as mg/kg (ppm)
Surrogate
Sample ID Gasoline Range (% Recovery )
Laboratory ID (Limit 58-139)
AB-02-7 <5 99
802285-01
AB-01-12 <5 97
802285-02
AB-03-12 <5 98
802285-03
AB-04-12 <5 95
802285-04
Method Blank <5 95
08-340 MB2
FIGURE B25
FRIEDMAN & BRUYA, INC.
_________________________________________________
ENVIRONMENTAL CHEMISTS
3
Date of Report: 02/22/18
Date Received: 02/16/18
Project: KCPCFM 170383, F&BI 802285
Date Extracted: 02/19/18
Date Analyzed: 02/19/18
RESULTS FROM THE ANALYSIS OF SOIL SAMPLES
FOR TOTAL PETROLEUM HYDROCARBONS AS
DIESEL AND MOTOR OIL
USING METHOD NWTPH-Dx
Results Reported on a Dry Weight Basis
Results Reported as mg/kg (ppm)
Surrogate
Sample ID Diesel Range Motor Oil Range (% Recovery)
Laboratory ID (C10-C25) (C25-C36) (Limit 48-168)
AB-02-7 <50 <250 101
802285-01
AB-01-12 <50 <250 97
802285-02
AB-03-12 <50 <250 108
802285-03
AB-04-12 <50 <250 109
802285-04
Method Blank <50 <250 101
08-375 MB
FIGURE B26
FRIEDMAN & BRUYA, INC.
_________________________________________________
ENVIRONMENTAL CHEMISTS
4
Date of Report: 02/22/18
Date Received: 02/16/18
Project: KCPCFM 170383, F&BI 802285
QUALITY ASSURANCE RESULTS FOR THE ANALYSIS OF SOIL SAMPLES
FOR TPH AS GASOLINE
USING METHOD NWTPH-Gx
Laboratory Code: 802300-01 (Duplicate)
Analyte
Reporting Units
Sample Result
(Wet Wt)
Duplicate
Result
(Wet Wt)
RPD
(Limit 20)
Gasoline mg/kg (ppm) <5 <5 nm
Laboratory Code: Laboratory Control Sample
Analyte
Reporting Units
Spike
Level
Percent
Recovery
LCS
Acceptance
Criteria
Gasoline mg/kg (ppm) 20 95 71-131
FIGURE B27
FRIEDMAN & BRUYA, INC.
_________________________________________________
ENVIRONMENTAL CHEMISTS
5
Date of Report: 02/22/18
Date Received: 02/16/18
Project: KCPCFM 170383, F&BI 802285
QUALITY ASSURANCE RESULTS FROM THE ANALYSIS OF SOIL
SAMPLES
FOR TOTAL PETROLEUM HYDROCARBONS AS
DIESEL EXTENDED USING METHOD NWTPH-Dx
Laboratory Code: 802289-01 (Matrix Spike)
Analyte
Reporting
Units
Spike
Level
Sample
Result
(Wet Wt)
Percent
Recovery
MS
Percent
Recovery
MSD
Acceptance
Criteria
RPD
(Limit 20)
Diesel Extended mg/kg (ppm) 5,000 <50 90 94 73-135 4
Laboratory Code: Laboratory Control Sample
Analyte
Reporting Units
Spike
Level
Percent
Recovery
LCS
Acceptance
Criteria
Diesel Extended mg/kg (ppm) 5,000 80 74-139
FIGURE B28
FRIEDMAN & BRUYA, INC.
_________________________________________________
ENVIRONMENTAL CHEMISTS
6
Data Qualifiers & Definitions a - The analyte was detected at a level less than five times the reporting limit. The RPD results may not provide reliable information on the variability of the analysis.
b - The analyte was spiked at a level that was less than five times that present in the sample. Matrix spike recoveries may not be meaningful.
ca - The calibration results for the analyte were outside of acceptance criteria. The value reported is an estimate.
c - The presence of the analyte may be due to carryover from previous sample injections.
cf - The sample was centrifuged prior to analysis.
d - The sample was diluted. Detection limits were raised and surrogate recoveries may not be meaningful.
dv - Insufficient sample volume was available to achieve normal reporting limits.
f - The sample was laboratory filtered prior to analysis.
fb - The analyte was detected in the method blank.
fc - The compound is a common laboratory and field contaminant.
hr - The sample and duplicate were reextracted and reanalyzed. RPD results were still outside of control limits. Variability is attributed to sample inhomogeneity.
hs - Headspace was present in the container used for analysis.
ht – The analysis was performed outside the method or client-specified holding time requirement.
ip - Recovery fell outside of control limits. Compounds in the sample matrix interfered with the quantitation of the analyte.
j - The analyte concentration is reported below the lowest calibration standard. The value reported is an estimate.
J - The internal standard associated with the analyte is out of control limits. The reported concentration is an estimate.
jl - The laboratory control sample(s) percent recovery and/or RPD were out of control limits. The reported concentration should be considered an estimate. js - The surrogate associated with the analyte is out of control limits. The reported concentration should be considered an estimate.
lc - The presence of the analyte is likely due to laboratory contamination.
L - The reported concentration was generated from a library search.
nm - The analyte was not detected in one or more of the duplicate analyses. Therefore, calculation of the RPD is not applicable.
pc - The sample was received with incorrect preservation or in a container not approved by the method. The value reported should be considered an estimate. ve - The analyte response exceeded the valid instrument calibration range. The value reported is an estimate.
vo - The value reported fell outside the control limits established for this analyte.
x - The sample chromatographic pattern does not resemble the fuel standard used for quantitation.
FIGURE B29
FIGURE B30
APPENDIX C
Stormwater Infiltration Analyses
ASPECT CONSULTING
PROJECT NO. 170383 - TASK 400 MAY 31, 2019 C-1
C. Stormwater Infiltration Analyses
As part of our stormwater infiltration analyses for the Site, the infiltration potential was
estimated using well permeameter testing (USBR, 1989) in infiltration wells. The
infiltration tests were performed within and near the area where the proposed infiltration
trench galleries are planned, based on the 30 percent drawings.
C.1. Infiltration Well Tests
Infiltration test wells MW-01 and MW-02 were constructed by drilling two 10-inch-
diameter 75-foot deep borings, placing vibrating-wire piezometers at the bottoms,
backfilling the boreholes with grout to approximately 26-feet bgs, and installing the well
casings. The wells consist of 6-inch diameter Schedule 40 polyvinyl chloride (PVC)
casing and a 10-foot-long steel V-wrap wire screen with 0.020-slots. The filter pack
encasing the screens is 6x9 Colorado Silica sand (see Appendix A for Boring Logs).
The test wells penetrate 10 feet into an approximately 53-foot relatively uniform
stratigraphy of unsaturated receptor soils consisting primarily of sandy and gravelly
glacial outwash deposits (Qpa) with low fines content. The bottom of the receptor soils
are bound by the top of the regional, unconfined aquifer.
Infiltration tests generally followed the procedure outlined in the U.S. Bureau of
Reclamation Well Permeameter method (USBR,7300-89). The infiltration tests were
performed on MW-01 between 13 feet and 23 feet bgs on April 22, 2019 and on MW-02
between 15 feet and 25 feet bgs. The test protocols consist of a constant head test (Phase
1) and falling head test (Phase 2).
The standard test procedure includes:
1. Adding water to the test well to maintain a constant hydraulic head in the
well.
2. Monitoring the flow rates and total water added with a flow meter.
3. Monitoring water levels within the test well with a pressure transducer.
4. Adjusting water flow rates until the water level in the well is constant
(less than 5% variation), or for a minimum of 4 hours.
5. Once the constant rate is achieved or the minimum duration reached,
Phase 1 is complete and Phase 2 is begun. The water source is shut-off
and the water levels monitored until it has fallen to less than 5 percent of
the total head targeted during the constant rate portion of the test.
Due to the high permeability of the receptor soils and access to finite water sources from
5,000-gallon water trucks, producing, maintaining, and measuring constant head levels
during the tests were a challenge. Rather than measuring stepped water levels and rates,
the tests consisted of using the maximum allowable flow rates the equipment was capable
of providing, which was between 90 and 140 gallons per minute (gpm). The groundwater
ASPECT CONSULTING
PROJECT NO. 170383 - TASK 400 MAY 31, 2019 2
response to testing was continuously monitored using vibrating wire piezometers
installed in the groundwater below the test wells. Table 3 in Section 2.5.3 provides the
constant head test flowrates and heads.
The test data are shown in the attached Figures C1 and C2 and in Table C1 below.
C.1.1. Infiltration Well Test Results
The infiltration well test data were analyzed using the USBR Well Permeameter equation
for Condition I, resulting in estimates of the bulk saturated hydraulic conductivity of the
infiltration receptor soil.
Table C1. Infiltration Test Results and Well Permeameter Variables
Variablea MW-01 MW-02
Q, gpm 90 118
Q, cfs 0.20 0.26
Q, ft3/day 17,280 22,464
H, ft 7.81 5.00
r, ft 0.42 0.42
Tu, ft 67 68
T, °C 11 12
µT 0.001271 0.001236
µ20 0.001003 0.001003
V 1.2671984 1.23230309
Kb, ft/day 168 468
Notes:
a) Refer to USBR 7300-89 for more detail on the Well Permeameter method, equations, and
variables.
No discernable groundwater response was measured during or after infiltration testing.
The results of translating the infiltration well test results into design infiltration rates for
infiltration trench galleries including safety factors, is described in Section 3.6 of the
Geotechnical Report.
Attachments
Figure C1 – MW-01 Borehole Injection Test Results
Figure C2 – MW-02 Borehole Injection Test Results
0.0
1.0
2.0
3.0
4.0
5.0
6.0
7.0
8.0
9.0
10.0
0 10 20 30 40 50 60 70 80Head of Water (feet)Elapsed Time (minutes)
King County Parks Central Maintenance Facility
Infiltration Well Testing
MW-01
Constant Head Test Data Selected for Analysis
Figure C1
0.0
1.0
2.0
3.0
4.0
5.0
6.0
7.0
0 25 50 75 100 125 150 175 200Head of Water (feet)Elapsed Time (minutes)
King County Parks Central Maintenance Facility
Infiltration Well Testing
MW-02
Constant Head Test Data Selected for Analysis
Figure C2
APPENDIX D
Vibrating-Wire Piezometers
Hydrograph
64.0
64.5
65.0
65.5
66.0
66.5
67.0
67.5
68.0
68.5
69.0
69.5
70.0
04/15/19 04/17/19 04/19/19 04/21/19 04/23/19 04/25/19 04/27/19 04/29/19 05/01/19Depth of Water (ft. bgs)Date
King County Parks and Recreation Division –Renton Shop
VW Piezometers
MW-01
MW-02
Infiltration Test
Infiltration Test
Depth 50 feet below soil receptor
Figure D1
APPENDIX E
King County May 22, 2017
Preliminary Geotechnical Design
Report – Subsurface Explorations
Department of Transportation
Road Services Division
Mailstop: RSD-TR-0100 | 155 Monroe Avenue NE, Bldg. D, Renton, WA 98056-4199
206-477-8100 | maint.roads@kingcounty.gov | www.kingcounty.gov/roads
DATE: May 24, 2017
TO: Brenda Bradford, Architect, Capital Project Management,
King County Department of Natural Resources and Parks
VIA: Alan Corwin, P.E., Engineer IV, Materials Lab Unit,
Road Services Division, King County Department of Transportation
FROM: Timothy Hyden, Engineer III, Materials Lab Unit,
Road Services Division, King County Department of Transportation
RE: Addenda No. 1
Project No. 1122161 – Preliminary Geotechnical Design Report
New King County DNRP Central Maintenance Facility
3005 NE 4th Street, Renton, Washington
As discussed, this letter is submitted as Addenda No. 1 to our Preliminary
Geotechnical Design Report for the referenced project originally dated May 11,
2017.
1) The title for Section 4.4 should be changed from “Wellhead Protection Area
Zones” to “Wellhead Protection Area Zones (Aquifer Protection Area)”, as the
City of Renton Critical Areas Ordinance uses both terms interchangeably.
2) Add the following paragraph to the end of Section 5.4.1:
In addition to the types of materials to be used for fill, the City of Renton
Municipal Code (4-4-060N) should be reviewed for other grading restrictions
related to fill slope locations, benching of fill slopes and submittal of a Source
Statement to preclude the import and use of contaminated fill soils.
Should you have questions, require clarification or desire additional information,
please contact Tim Hyden (206-477-0983) or Alan Corwin (206-296-7711) at your
convenience.
cc: Bing Subelbia, Project Program Manager IV
tQ King County
DATE:
TO:
VIA:
Department of Transportation
Road Services Division
May 11 , 2017
Brenda Bradford, Architect , Capital Project Management,
King County Department of Natural Resources and Parks
~n. P.E., Engineer IV, Materials Lab Unit,
R~a~~ices Division, King County Department of Transportation
. FROM:~ Hyden , Engineer Ill, Materials Lab Unit,
Road Services Division, King County Department of Transportation
RE: Project No. 1122161 -Preliminary Geotechnical Design Report
New King County DNRP Central Maintenance Facility
3005 NE 4th Street, Renton, Washington
-As requested, we have completed a preliminary geotechnical engineering study for
the new King County DNRP Central Maintenance Facility to be located in Renton,
Washington.
Our work was performed and this report prepared to addresses the items included
with the approved scope of work as detailed by our proposal and cost estimate
dated March 17, 2017. This report summarizes the results of our site
reconnaissance, literature review, subsurface exploration , critical area and geologic
hazards evaluation, and provides recommendations for development, design and
construction.
Should you have questions , require clarification or desire additional information,
please contact Tim Hyden (206-4 77-0983) or Alan Corwin (206-296-7711) at your
convenience.
cc: Bing Subelbia, Project Program Manager IV
Mailstop : RSD -TR-0100 I 155 Monroe Av enu e NE , Bldg . D, Rent on, WA 98 056 -41 99
206-477 -8100 I maint.roads@kingcounty .gov I www.k ingcounty .gov/roads
TABLE OF CONTENTS (Page 1 of 2)
Project No. 1121161 -Preliminary Geotechnical Design Report
New King County DNRP Central Maintenance Facility
3005 NE 4th Street, Renton, Washington
SECTION 1 -INTRODUCTION ........................................................................................................ 1
SECTION 2 -PROJECT OVERVIEW ............................................................................................. 1
SECTION 2.1 -SITE DESCRIPTION ........................................................................................... 1
SECTION 2.2 -PLANNED DEVELOPMENT ............................................................................... 1
SECTION 2.3-ADJACENT PROPERTIES ................................................................................. 2
SECTION 3 -SURFACE AND SUBSURFACE CONDITIONS ...................................................... 2
SECTION 3.1 -GEOLOGIC RECONNAISSANCE AND MAPPING ............................................ 2
SECTION 3.2-SUBSURFACE EXPLORATION ......................................................................... 3
Subsection 3.2.1 -Borings 8-1 through B-5 ............................................................................. 3
Subsection 3.2.2-Boring 8-6 .................................................................................................. 4
Subsection 3.2.3-Oversize Materia/s ...................................................................................... 4
SECTION 3.3-SITE SPECIFIC BORING LOCATIONS ............................................................. 4
SECTION 3.4 -PREVIOUS EXPLORATION .............................................................................. .4
SECTION 3.5 GROUNDWATER ............................................................................................... 4
SECTION 4 -CRITICAL AREA IDENTIFICATION ........................................................................ 5
SECTION 4.1 -SENSITIVE SLOPES .......................................................................................... 5
SECTION 4.2 -PROTECTED SLOPES ....................................................................................... 6
SECTION 4.3-DETERMINATION OF REGULATED SLOPE LOCATIONS ................................ 6
SECTION 4.4 -WELLHEAD PROTECTION ZONES ................................................................... 6
SECTION 5 -ANALYSIS, CONCLUSIONS AND RECOMMENDATION ...................................... 6
SECTION 5.1-TEMPORARY EROSION AND SEDIMENTATION CONTROL. .......................... 6
SECTION 5.2 -STORMWATER INFILTRATION ......................................................................... 7
SECTION 5.3-SUBGRADE PREPARATION ............................................................................. 8
SECTION 5.4 -FILL FOR SITE GRADING .................................................................................. 8
Subsection 5.4.1 -Fill Materials ............................................................................................... 8
Subsection 5.4.2-Fill/Backfill Moisture Content and Compaction Leve/ ................................. 8
SECTION 5.5-UTILITY CONSTRUCTION ................................................................................. 9
SECTION 5.6-EXCAVATION SAFETY ...................................................................................... 9
SECTION 5.7 -SHALLOW FOUNDATIONS BEARING CAPACITY ............................................ 9
SECTION 5.8 -SHALLOW FOUNDATION SETTLEMENT ....................................................... 10
SECTION 5.9-ALTERNATE FOUNDATION/SLAB BEARING SURFACE PREP .................... 10
TABLE OF CONTENTS (Page 2 of 2)
Project No. 1121161 -Preliminary Geotechnical Design Report
New King County DNRP Central Maintenance Facility
3005 NE 4th Street, Renton, Washington
SECTION 5.10-SEISMIC DESIGN CONSIDERATIONS .......................................................... 10
Subsection 5.10.1-Seismic Ground Motion Values .............................................................. 10
Subsection 5.10.2-Seismic Hazard Areas ............................................................................ 11
Subsection 5. 10.3 -Liquefaction ............................................................................................ 11
Subsection 5.10.4-Seismically Induced Landslides ............................................................. 11
Subsection 5.10.5-Ground Rupture ...................................................................................... 11
SECTION 6.0-ASPHALT PAVING .............................................................................................. 12
SECTION 7 .0 -CLOSURE ............................................................................................. : .............. 12
SECTION 8.0 -REFERENCES ..................................................................................................... 13
LIST OF FIGURES
FIGURE 1: FIGURE 1 -VICINITY MAP
FIGURE 2: FIGURE 2 -BORING LOCATION PLAN
FIGURE 3: FIGURE 3 -CRITICAL AREAS
APPENDICES
APPENDIX A-BORING LOGS AND LABORATORY TEST REPORTS
Project No. 1122161 -Preliminary Geotechnical Design Report
New King County DNRP Central Maintenance Facility
3005 NE 4th Street, Renton, Washington
(Page 1 of 14)
1.0 INTRODUCTION
As requested, we have completed a preliminary geotechnical engineering investigation for
the new King County Department of Natural Resources and Parks Central Maintenance
Facility. This report was prepared to characterize site, soil and groundwater conditions for
project planning and preliminary design. The types, size and locations of specific structures
or improvements have not yet been fully determined. As the project progresses, additional
field exploration, engineering analysis and recommendations for design and construction
may be needed.
2.0 PROJECT OVERVIEW
2.1 Site Description
The subject property at 3005 NE 4th Street (Parcel 1434000012) is approximately 5 acres
with dimensions on the order of 600 lineal feet, east to west, and 420 lineal feet, north to
south. The property is relatively flat with approximately 5 feet of relief sloping downward
from east to west. In addition, along the western property line, there is a steep downward
slope to the adjacent property.
Currently, offices, maintenance structures and other ancillary buildings are on the DNRP
Central Maintenance Facility site. Portions of the site without structures are covered with
asphalt pavement, gravel surfacing and landscaping.
In addition to the subject property, negotiations are underway for an easement on the
adjacent property to the north located at 3001 NE 4th Street (Parcel 1623059130). The
easement will be along the west border of the property and is intended to provide access to
utilities off NE 4th Street. The planned easement area is currently undeveloped, with a gentle
east to west downward slope and covered with small trees, scrub brush and grasses.
A site vicinity map is attached as Figure 1.
2.2 Planned Development
Current plans are to demolish most of the existing structures and construct new facilities.
The new office and maintenance buildings may be up to three stories in height. Shallow
spread footing foundations are planned and foundation loads are anticipated to be relatively
light.
Preliminary plans indicate the new buildings will likely be located on the eastern half of the
property. Covered and uncovered materials storage buildings, a sawmill shelter and,
possibly, a retaining wall may be constructed along the west side of the property. Site areas
Mailstop: RSD-TR-0100 I 155 Monroe Avenue NE, Bldg. D, Renton, WA 98056-4199
206-477-8100 I maint.roads@kingcounty.gov I www.kingcounty.gov/roads
Job No. 1121161 -Preliminary Geotechnical Design Report
King County DNRP Maintenance Facility, Renton, WA
May 11, 2017
Page 2 of 14
where building construction is not planned will primarily be used for parking and
landscaping, and stormwater retention and/or infiltration facilities are being considered.
2.3 Adjacent Properties
For a distance of 150 feet beyond the site perimeter and proposed easement, natural and
man-made features include the following:
North Side: Renton Housing Authority Residential Property (Parcel 1623059120), AM PM
Convenience Store and Gas Station (Parcel 1623059115) and the currently vacant King
County Public Health Offices (Parcel 1623059130). Surfaces surrounding the occupied
structures on these three properties include asphalt/concrete pavement and landscaped
areas. In addition, a section of NE 3rd Street, a City of Renton roadway, is within the 150-foot
zone.
East Side: An asphalt paved access road (Parcel 1434000010) for other King County
facilities in the area is directly adjacent to the planned DNRP Maintenance Facility. In
addition, there is an approximate 50 foot deep depression that was previously used to mine
sand and gravel (Parcel 1623059059). This parcel has an active City of Renton grading
permit (No. B 16005811) and contains regulated steep slopes and a designated wetland
area.
South Side: The property to the south (Parcel 1434000020) is owned by King County and
includes a gravel surfaced equipment storage area and other undeveloped property with
natural vegetation.
West Side: Commercial properties (Parcels 1623059144 and 1623059143) that include
office and storage facilities, essentially surrounded by asphalt surfacing. The City of Renton
has issued a preliminary building permit for Parcel 1623059144 to remove an existing
building and add a new three-story building totaling approximately 58,350 square feet.
3.0
3.1
SURFACE AND SUBSURFACE CONDITIONS
Geologic Reconnaissance and Mapping
The project area is located in the Puget Lowland, bounded by the Olympic Mountains to the
west, and the Cascade Mountains to the east, in the bluff area of the Renton Highlands
north of the Cedar River Valley. The topography in the Puget Sound Basin was created by
repeated glacial advancement and retreat, and postglacial processes.
Review of the 1965 USGS Geologic Map of the Renton Quadrangle shows Recessional
Stratified Drift as the single geologic unit within the project site boundaries and adjacent
properties. On a geologic time scale, this unit originates from the Upper Pleistocene series of the
Quaternary Period and is summarily described as follows:
Recessional Stratified Drift (Qpa): Sandy pebble and cobble gravel in easternmost terraces,
grades to interbedded sand and pebble gravel at Renton and to sand at north edge of
quadrangle.
Job No. 1121161 -Preliminary Geotechnica/ Design Report
King County DNRP Maintenance Facility, Renton, WA
May 11, 2017
Page 3 of 14
During our site reconnaissance, outwash gravels and sands were visible along the western
property boundary slope and on the side-slopes of the inactive sand and gravel mining pit
located east of the property. Based on the noted soil exposures, review of published
literature and subsurface exploration, we anticipate outwash sands and gravels underlie the
entire planned project area to a depth of 30 feet or more below the existing ground surface
{bgs).
3.2 Subsurface Exploration
Site-specific soil and groundwater conditions were explored on April 13, 2017 by completing
a total of 6 geotechnical test borings. Holocene Drilling completed the borings using a
Diedrich D-50 track-mounted drill rig by advancing 8-inch nominal outside diameter hollow-
stem auger. Five of the borings were completed to a depth of 26.5 feet bgs in the existing
DNRP Maintenance Complex (Parcel No. 1434000012) and one boring was completed to a
depth of 16.5 feet bgs for the proposed utility easement to be located along the west side of
the adjacent property to the north (Parcel No. 1623059130).
Standard Penetration Tests (SPT) were performed at 2.5-foot intervals to a depth of 10-feet
bgs and at 5.0-foot intervals thereafter to the boring termination depths. The SPT provides a
measure of compaction or relative density of granular soils, and consistency or stiffness of
cohesive fine-grained soils. Disturbed but representative soil samples were collected, when
retrieved, at each SPT testing interval, and returned to our laboratory for further evaluation
and testing.
Soils classified during subsurface site exploration were generally consistent with those
described by the referenced geologic mapping. A summary of the subsurface soil profile
encountered during our investigation is provided below:
3.2.1 Borings B-1 through B-5
Soils encountered during drilling were generally consistent throughout the site. Gravel
surfacing mixed with sand and silt in a medium dense to very dense state was encountered
from the existing ground surface to depths of approximately 0.25 to 0.50 feet. Silty sand and
mixtures of sand and gravel, interpreted as man-made fill, were encountered below the
gravel surfacing to depths of about 2.5 to 5.0 feet bgs in Borings B-1, B-3, B-4 and B-5.
Predominantly, the fill material was in a loose condition with respect to relative density.
However, just below the gravel surfacing near the ground surface, the fill ranged from
medium dense to very dense, likely due to compaction from traffic and periodic gravel
surfacing maintenance.
At Boring B-2 and below the fill from Borings B-1, B-3, B-4 and B-5, the soils predominantly
consisted of medium dense mixed sands and gravels sandy gravels to depths ranging from
about 15 to 22.5 feet bgs. The underlying soil horizon predominantly consisted of medium
dense, poorly graded, fine to medium grained sands interspersed with varying amounts of
gravel to the termination depth of our borings at 26.5 feet bgs.
Job No. 1121161 -Preliminary Geotechnical Design Report
King County DNRP Maintenance Facility, Renton, WA
3.2.2 Borin_g B-6
May 11, 2017
Page 4 of 14
A few inches of topsoil and organic material was encountered at the existing ground surface
followed by loose, silty sand with gravel to a depth of 1.5 feet bgs. Loose to medium dense,
fine to medium grained poorly graded sand with traces of gravel was encountered below the
topsoil to a depth of about 6.5 feet bgs. The underlying soil consisted of medium dense to
dense, poorly and well graded sands with varying gravel contents to the boring termination
depth at 16.5 feet bgs.
3.2.3 Over-size Materials
With the nominal 8-inch diameter hollow-stem auger, it is difficult to determine the
percentage of cobbles and, potentially boulders, in the underlying soil deposits as minimal
amounts are generally lifted by the auger flights and deposited on the ground surface as
drilling spoils. However, cobbles were observed that will likely be encountered during
construction, potentially with occasional small boulders.
3.3 Site Specific Boring Locations
An aerial photograph of the site showing approximate boring locations is attached as Figure
2. Copies of the boring logs (Figures A-1 through A-6) and laboratory test results from select
samples (Figures A-7 through A-12) are provided in Appendix A. Approximate GPS
coordinates were obtained from the test boring locations at the time of drilling and are
summarized below in Table 1.
TABLE 1
Boring Number Coordinates GPS (Reporled Accuracy +16 Feet)
8-1 4 7.486442 °N 122.179930 °w
8-2 4 7.486380 °N 122.178830 °w
8-3 47.485957 °N 122.179120 °w
8-4 47.486526 °N 122.178215 °w
8-5 4 7.486525 °N 122.178989 °w
8-6 47.487170 °N 122.180187 °w
3.4 Previous Exploration
Our records show two test pits were excavated to depths ranging from 4.5 to 5.5 feet during
previous exploration of the DNRP Maintenance Complex property. In general, approximately
2 to 2.5 feet of medium dense to dense gravely sand fill overlies medium dense to dense
native sand and gravel outwash soils, to the termination depth of the test pits.
3.5 Groundwater
Soils encountered at the time of drilling were in a generally moist condition and no
groundwater was encountered. City of Renton mapping designates the general northeast
quadrant of the inactive sand and gravel mine to the east of the property as a wetland. At its
closest point, mapping shows the wetland area about 250 feet from the northeast corner of
the DNRP Maintenance Site property. During our site reconnaissance, standing water was
Job No. 1121161-Preliminary Geotechnica/ Design Report
King County DNRP Maintenance Facility, Renton, WA
May 11, 2017
Page 5 of 14
observed in the designated wetland area approximately 45 feet in elevation below the DNRP
Maintenance Facility Site.
Review of boring logs from a previous geotechnical investigation performed for the King
County Regional Communications and Emergency Coordination Center indicate perched
groundwater was encountered at the interface of the outwash materials and underlying till,
at depths ranging from 24 to 47 feet below the existing ground surface. This site lies
approximately 2,500 feet to the southeast of the DNRP Maintenance Site.
We reviewed the Washington State Department of Ecology interactive website for drill logs
of any wells located within %~mile of the DNRP Maintenance Site. A total of 7 records were
found, 3 for Resource Protection wells and 4 for decommissioned wells. Records indicate
the wells ranged from 15 to 36 feet below the ground surface. One of the records for the
Renton Highlands Landfill (Well Log 328114) indicated groundwater was at a depth of 11
feet bgs and another record for Nickelson Development (Well Log 328143) indicated a water
sample was taken using a push-probe at a depth of 17 feet bgs. Groundwater identified by
these two well logs is likely perched. The remaining well logs did not indicate the presence
or depth of groundwater.
4.0 CRITICAL AREA IDENTIFICATION
From a geotechnical perspective, typical activities associated with site development such
as clearing and grading, utility placement, and building construction will have no
adverse impacts on surrounding properties provided City of Renton and/or other
regulatory requirements for design and construction are implemented.
The City of Renton's Maps (COR), an online interactive mapping application, was reviewed
to determine whether any designated Critical Areas are present at the project site (Parcel
1434000012) and proposed utility easement (Parcel 1623059130). Critical Areas identified
as geologic hazards by the Renton Municipal Code (RMC) Section 4-3-050 include Steep
Slopes, Landslides, Erosion, Seismic and Coal Mines. Based on the COR, geologic
hazards for this site exist only along the west property boundary as Sensitive and Protected
Slopes. In addition to geologic hazards, the entire property and planned easement area are
identified by the COR as being within a Well Head Protection Area -Zone 1 Modified. A
map showing the Critical Areas within the project boundaries is attached as Figure 3.
We have not performed a slope stability analysis for the sensitive and protected slopes
along the west side of the property. As the project develops, a stability analysis can be
performed and recommendations provided, if needed, for improved slope stabilization,
erosion protection or design of an earth retaining structure.
4.1 Sensitive Slopes
Sensitive Slopes are defined by the City of Renton as a hillside, or potion thereof, having an
average slope between 25 and 40 percent, an average slope greater than 40 percent with
less than 15 foot vertical rise or property abutting a slope with an average slope between 25
to 40 percent. During construction, weekly on-site inspections and reports documenting
adequate performance of erosion control measures are required. Generally, there is no
critical area buffer or set-back required for Sensitive Slopes.
Job No. 1121161-Preliminary Geotechnica/ Design Report
King County DNRP Maintenance Facility, Renton, WA
4.2 Protected Slopes
May 11, 2017
Page 6 of 14
A Protected Slope is defined as a hillside, or portion thereof, having an average slope of 40
percent or greater with a minimum 15-foot vertical rise. Development is prohibited on
protected slopes, although there are provisions for potential exceptions addressed by
Section 4-3-050, Subsection J of the Renton Municipal Code. A critical area buffer is
typically not required for protected slopes; however, a minimum 15-foot structure set-back
applies. In addition, weekly inspections and reports documenting effectiveness of erosion
control measures are required.
4.3 Determination of Regulated Slope Locations
The location of sensitive or protected slopes is determined from identification on the City of
Renton's COR Maps. Survey data with 2-foot contour intervals or the standard utilized in the
City of Renton Steep Slope Atlas may be submitted to the City of Renton for consideration in
determining alternate sensitive or protected slope boundaries.
COR Mapping shows the Sensitive and Protected slopes are along the south half of the
western property boundary and the slope toe appears to terminate on the adjacent property
to the west. At the steepest point of inclination, COR mapping along the western property
line shows the slope to be about 1.35(H): 1 (V) with approximately 14 feet of vertical relief.
4.4 Wellhead Protection Area Zones
The City of Renton designates different zones Wellhead Protection Area Zones to provide
graduated groundwater protection levels. Zone 1 Modified encompasses the same land area
as Zone 1, defined as being situated between a City-owned well or well field and the
distance groundwater will travel over 365 days. The modification is intended to protect a
high-priority well, well-field or spring withdrawing from a confined aquifer with some degree
of leakage into overlying or underlying confining layers. The City may require a permit
applicant to submit a hydrogeologic study if the proposed project has the potential to
significantly impact groundwater quantity or quality, and sufficient information is not readily
available.
5.0 ANALYSIS. CONCLUSIONS AND RECOMMENDATIONS
The results of our analysis, conclusions and recommendations for geotechnical design
and construction considerations is provided below. We understand the project is
currently in the initial planning and preliminary design stages. Specific information as to
the type, size and location of structures or other site improvements is not yet available.
We should be consulted as project design progresses, and given the opportunity to
review and, if needed, revise our recommendations accordingly.
5. 1 Temporary Erosion and Sedimentation Control
Site development activities can significantly increase the potential for erosion and
sedimentation transport as a result of vegetation removal, alteration of soil
characteristics, and changes to topography and drainage. The degree of erosion and
Job No. 1121161 -Preliminary Geotechnical Design Report
King County DNRP Maintenance Facility, Renton, WA
May 11, 2017
Page 7 of 14
sedimentation transport is highly dependent on soil types, slope gradient and
concentration of surface water flows.
The DNRP Maintenance site has minimal cross slope, is relatively flat and soils
exposed during construction will generally consist of sandy gravels and gravelly sands.
Under these conditions, runoff will be slow and the potential for erosion and
sedimentation transport minimal. Therefore, standard Temporary Erosion and
Sedimentation Control (TESC) construction best management practices (BMPs) will be
effective in controlling erosion and preventing sediment transport to offsite drainage
systems and adjacent properties. Depending on site development plans, typical TESC
measures could include:
• Establishing clearing limits and buffers;
• Installation of silt fence, wattles and/or similar measures as a buffer or for
perimeter protection;
• Minimize the size and duration of exposed soil areas at any given time;
• Cover and grade around stockpiles and exposed soil areas to minimize exposure
to precipitation and control runoff;
• Installation of a construction entrance/exit and stabilization of heavy traffic areas;
• Control surface water run-off rates and direction of flow;
• Install temporary sediment retention ponds or storage tanks and protect
stormwater system inlets; and
• Dust control.
The civil engineer should prepare project specific TESC plans for submittal to the City of
Renton. The TESC plan should consider seasonal wet weather construction periods
and potential impacts to designated Critical Areas. In addition, permitting typically
requires weekly inspections, monitoring discharge Nephelometric Turbidity Units (NTU)
and periodic report submittals during construction.
5.2 Stormwater Infiltration
As indicated previously, the site is underlain by outwash sands and gravels estimated to
extend to a depth of at least 30 feet bgs. While on site for general reconnaissance and
subsurface exploration, no standing water was observed on the ground surface. In
addition, impermeable soil layers that would restrict infiltration were not encountered
during our subsurface exploration and groundwater is expected to be 30 feet or more
below the existing ground surface.
In our opinion, the outwash sands and gravels would generally be well suited for
stormwater infiltration. However, given that the site is in a Wellhead Protection Area, the
City of Renton may require pre-treatment or have other restrictions controlling or
preventing stormwater infiltration. If infiltration is deemed feasible with regard to
regulatory constraints, additional field testing should be performed to determine in-situ
infiltration rates.
Job No. 1121161 -Preliminary Geotechnica/ Design Report
King County DNRP Maintenance Facility, Renton, WA
May 11, 2017
Page 8 of 14
5.3 Subgrades for Site Grading, Foundations, Building Pads and Pavements
At finished subgrade elevations in cut areas and in areas scheduled to receive fill, the
exposed ground surface should be cleared of all vegetation, topsoil, asphalt/concrete
pavements and any other deleterious material. A representative from our office should
be on site to verify the suitability of exposed soils and provide recommendations if
unsuitable soil conditions are encountered and over-excavation is necessary.
The exposed soil surface should be scarified to a minimum depth of 12-inches,
processed into a homogeneous mixture and moisture conditioned to within ±. 2-percent
of the optimum moisture content. The subgrade should be compacted to a minimum of95-
percent of the maximum dry density as determined by the Washington State
Department of Transportation Standard Specifications for Roads and Bridges (WSDOT)
Section 2-03.3(14)0 and, when completed, should be in a firm and unyielding condition.
Prepared subgrades should be evaluated and approved by a representative from our
office prior to permanent covering.
5.4 Fill for Site Grading. Embankments, Building Pads and Paved Areas
5.4.1 Fill Materials
Fill materials should meet the requirements for Select Borrow as defined by WSDOT
Standard Specification (WSDOT) 9-03.14(3). The WSDOT standard Select Borrow
gradation should be modified by reducing the maximum allowable particle size so that
100-percent of the material is finer than a 3-inch square sieve. It is anticipated some of
the sandy gravels and gravelly sands encountered during our subsurface exploration
will meet this requirement; however, variations of the soil profile should be expected
and processing of excavated soils and/or blending with imported soil may be necessary.
Due to an allowable silt and/or clay content of up to 10-percent, Select Borrow may not
be suitable for fill during periods of wet weather and/or if the moisture content is in
excess of optimum. Gravel Borrow meeting WSDOT 9-03.14(1) requirements should be
used during wet weather periods if excess moisture prevents adequate compaction
and/or a firm and unyielding surface condition from being achieved. As with Select
Borrow, the WSDOT specified gradation for Gravel Borrow should be modified by
reducing the maximum allowable particle size to 3-inches.
Rather than reiterating when the use of Select Borrow or Gravel Borrow may be
appropriate for specific grading applications, from hereinafter whenever Select Borrow
is recommended, it is with the understanding that Gravel Borrow may be required
depending on weather conditions, moisture content and the ability to compact soils to a
firm and unyielding condition.
5.4.2 Fill/Backfill Moisture Content and Compaction Level
Unless otherwise specified in this report, all fill and backfill should be placed in
horizontal lifts with a maximum loose thickness of 8-inches. The fill or backfill material
should be moisture conditioned as necessary to within ±. 2 percent of optimum moisture
Job No. 1121161 -Preliminary Geotechnica/ Design Report
King County DNRP Maintenance Facility, Renton, WA
May 11, 2017
Page 9 of 14
and compacted to a minimum of 95 percent of the maximum dry density as determined
by WSOOT 2-03.3(14)0.
5.4.3 Protection of Work
Fill sections and cut sections excavated to subgrade elevations should be protected
from damage by traffic, construction operations and environmental conditions during
grading operations and until the final surfacing, structures or erosion protection is in-
place. Permanent slopes of all newly constructed embankments should be graded at 2
Horizontal (H): 1 Vertical (V) or flatter and protected from erosion by controlling surface
water runoff. For general erosion protection, topsoil and appropriate vegetation should
be placed in landscaped areas or other areas not covered by structures or other
surfacing materials.
5.5 Utility Construction
Underground utilities can be supported on the granular native soils provided the trench
bottom is free of organic material or debris, and compacted per Section 5.3.2 of this
report. All utilities are to be bedded with Gravel Backfill for Pipe Zone Bedding
meeting the requirements of WSOOT 9-03.12(3). The Gravel Backfill for Pipe Zone
Bedding should extend a minimum of six inches above and below the utility and be
compacted to at least 90 percent of the maximum dry density as determined by
WSOOT 9-03.3(14)0.
The remainder of the utility trench should be backfilled with Select Borrow placed
and compacted per Section 5.3.2 of this report. Alternatively, native sands and
gravels may be substituted for backfill provided they are at a moisture content and
gradation acceptable to the engineer at the time of construction.
5.6 Excavation Safety
The site soils are granular and subject to shallow sloughing. Therefore, the contractor
must take special precautions to protect workers entering trench or footing excavations.
Maintenance of a safe working environment, including shoring, is the responsibility of
the contractor. Temporary trench excavations or vertical cuts greater than four feet in
height must be in compliance with current Occupational Safety & Health Administration
(OSHA) and Washington Administrative Code (WAC) requirements for excavating,
trenching, and shoring.
In general, we recommend the use of trench boxes to support utility trenches.
Alternatively, the excavation can be cut back to a temporary slope no steeper than 1
%(H): t(V). However, depending on site conditions observed by the contractor, additional
flattening of the temporary slope may be required.
5.7 Shallow Foundations Bearing Capacity
The near surface medium dense sand and gravel soils will provide adequate support for
the use of shallow foundations for retaining walls and buildings. However, loose silty sand
and sandy gravel soils were encountered to a depth of up to 5.0 feet bgs in some of the
Job No. 1121161-Preliminary Geotechnica/ Design Report
King County DNRP Maintenance Facility, Renton, WA
May 11, 2017
Page 10 of 14
borings. The loose soils were interpreted as man-made fill and are not considered
suitable for foundation support in their present condition.
A representative from our office should be on site during foundation excavation to
evaluate exposed soil conditions and provide recommendations for over-excavation if
loose soils are encountered at the design foundation bearing elevation. Loose soils
should be removed by extending the excavation to the medium dense sands and
gravels. The resulting void should be backfilled with Select Borrow placed and
compacted as described in Section 5.3.2.
Foundations should bear a minimum of 1.5 feet below the lowest adjacent grade. The native
sand and gravel soils and Select Borrow backfill placed in any over-excavated areas would
be relatively free-draining and not highly susceptible to frost action. However, foundations
should be extended deeper than 1.5 feet if required by local building codes or other project
specific reasons not related to allowable bearing capacity.
For shallow foundations prepared as stated above, an allowable bearing capacity of 3,000
psf and coefficient of base friction of 0.40 can be assumed for design purposes. In addition,
we recommend assuming a 1/3 increase in the allowable bearing capacity to account for
transient loads associated with wind and seismic activity. We can perform additional
exploration and/or analysis once building locations have been determined if an increase to
the allowable bearing capacity is needed.
5.8 Shallow Foundation Settlement
Provided foundations are prepared as recommended above, total settlement is estimated at
0.5 inches with differential settlement estimated at 0.25 inches for an allowable bearing
capacity of 3,000 psf. Given the anticipated granular soil conditions, the majority of
settlement will occur during construction immediately upon loading.
5.9 Alternate Foundation and Slab Bearing Surface Preparation
Gravels and cobbles exposed after excavating to foundation or slab-on-grade subgrade
elevations may result in an uneven or irregular bearing surface. If desired, the excavation
could be extended approximately 4-inches and the resulting void backfilled with Crushed
Surfacing Base Course (CSBC) to provide a smooth, plane bearing surface and improved
control for final grading, setting of formwork and installation of reinforcing steel. CSBC
should meet the requirements of WSDOT 9-03.9(3) and be placed and compacted as
described by Section 5.3.2 of this report.
5.10 Seismic Design Considerations
5.10.1 Seismic Ground Motion Values
Recommendations for seismic design values are based on procedures outlined in the 2015
International Building Code (IBC) for Risk Categories I, II and Ill. Site response parameters
were obtained from the USGS Earthquake Hazards website with site coefficients
established by interpolating values from IBC Tables 1613.3.3(1) and 1613.3.3(2). Latitude
and longitude coordinates used to calculate site coefficients are 47.286318 and
Job No. 1121161 -Preliminary Geotechnica/ Design Report
King County DNRP Maintenance Facility, Renton, WA
May 11, 2017
Page 11 of 14
-122.178896, respectively. Recommended values addressing IBC Sections 1613.3.1,
1613.3.2 and 1613.3.3 are provided in Table 2 below:
TABLE 2
Site MCE Spectral Site Adjusted Spectral Design Spectral
Class Response Response Acceleration (g) Coefficients Parameters Parameters
Ss S1 Fa Fv Sms Sm1 Sos 801
(.2 sec) (1-sec) (.2 sec) (1-sec) (.2 sec) (1-sec)
D 1.416 0.531 1.0 1.5 1.416 0.796 0.944 0.531
5.10.2 Seismic Hazard Areas
Typically, high seismic hazard areas are those areas subject to severe risk of earthquake
damage as a result of seismically induced soil liquefaction, sliding, or ground rupture. The
Puget Lowland experiences between 1,000 and 2,000 earthquakes yearly. However, the
vast majority of these earthquakes have magnitudes (M) of less than 3.0 and go unnoticed
by the general population. Primary sources of earthquakes in the Puget Lowland include
shallow, deep, and subduction-zone earthquakes. City of Renton online mapping indicates
the project site is not within a designated Seismic Hazard Area.
5.10.3 Liquefaction
Liquefaction occurs when loose saturated granular soils such as fine sand and coarser silts
become fluid-like, losing their ability to support loads during a seismic event, resulting in
ground settlement and deformation. Seismically induced liquefaction usually occurs in areas
underlain by generally cohesionless soils of low density in conjunction with shallow
groundwater. Since the project site is underlain by medium dense to dense sands and
gravels, with relatively deep groundwater, the risk of liquefaction in our opinion is low. In
addition, mapping by the Washington State Department of Natural Resources indicates the
potential for liquefaction susceptibility to be very low.
5.10.4 Seismically Induced Landslides
Areas most prone to seismically induced landslides would have steep slopes, shallow
groundwater and soils prone to a rapid rise in porewater pressures. With the exception of
the slope along the west property boundary, the DNRP Maintenance Facility site is generally
flat and has unsaturated granular soils to an estimated depth of at least 30 feet. Based on
topography and available subsurface information, the future risk of a seismically induced
landslide at this site is considered to be low in our opinion.
5.10.5 Ground Rupture
A significant number of active fault lines or cracks in the earth's crust have been identified
by the USGS in the central Puget Sound area, including Seattle and King County. However,
the closest major fault identified in the vicinity of the project area is the Seattle Fault that
generally follows the 1-90 corridor. In addition, during our field reconnaissance, no evidence
to indicate surface ground rupture has previously occurred at the site was observed.
Job No. 1121161 -Preliminary Geotechnical Design Report
King County DNRP Maintenance Facility, Renton, WA
8.0 REFERENCES
City of Renton, COR Maps,
http://rp.rentonwa.gov/SilverlightPublic/Viewer.html?Viewer=COR-Maps
City of Renton Municipal Code, Section 4-3-050, Critical Areas Regulations,
May 11, 2017
Page 13 of 14
http://www. codepu blish ing. com/W NRenton/html/Renton04/Renton0403/Renton0403050. ht
ml
City of Renton Municipal Code, Section 4-8-120, Submittal Requirements, Table 18,
http://www. codepublish ing. com/W NRenton/html/Renton04/Renton0408/Renton0408120. ht
ml
International Code Council, 2015, International Building Code
KCGIS Center (October 3, 2016); King County iMAP; Data Retrieved April 19, 2017;
http://gismaps.kingcounty.gov/iMap/
King County Materials Laboratory, October 13, King County Renton Facility Short Plat-
Geotechnical Investigation, Renton, Washington
My NASA Data, Latitude Longitude Finder, September 9, 2016;
https://mynasadata. I arc. nasa. gov/latitudelong itude-fi nder/
United States Department of the Interior, U.S. Geologic Survey, Geologic Map of the Renton
Quadrangle, King County Washington, 1965, 1 :24,000 scale, Mullineaux, D.R.
United States Department of the Interior, U.S. Geological Survey, USGS Earthquake Hazard
Program, Derived in 2008 from USGS Hazard Data;
https://earthquake.usgs.gov/designmaps/us/application.php
Washington State Department of Natural Resources, 2016; Geologic Information Portal
http://www.dnr.wa.gov/geologyportal
Washington Division of Geology and Earth Resources, Open File Report 2015-05, Faults
and Earthquakes in Washington State, 2014, Jessica L. Czajowski and Jeffrey D. Bowman,
http://file.dnr.wa.gov/publications/ger ofr2014-05 fault earthquake map.pdf
Washington Division of Geology and Earth Resources, Open File Report 2004-20,
Liquefaction Susceptibility and Site Class Maps of Washington State, By County
Map 17A -Liquefaction Susceptibility, Sheet 33 of 78, Stephen P. Palmer, et. Al,
September, 2004, ftp://ww4.dnr.wa.gov/geology/pubs/ofr04-20/ofr2004-
20 sheet33 king liq.pdf
Washington Division of Geology and Earth Resources, Open File Report 2004-20,
Liquefaction Susceptibility and Site Class Maps of Washington State, By County
Job No. 1121161 -Preliminary Geotechnical Design Report
King County DNRP Maintenance Facility, Renton, WA
May 11, 2017
Page 14 of 14
Map 178-King County NEHRP Site Class, Sheet 34 of 78, Stephen P. Palmer, et. Al,
September, 2004, ftp://ww4.dnr.wa.gov/geology/pubs/ofr04-20/ofr2004-
20 sheet34 king nehrp.pdf
Washington Division of Geology and Earth Resources, 2016, Surface Geology, 1 :24,000--
GIS data, November 2016: Washington Division of Geology and Earth Resources Digital
Data Series DS-10, version 2.0, previously released June 2014,
https://fortress.wa.gov/dnr/protectiongis/geology/?Theme=subsurf
Washington State Department of Ecology, Well Log Viewer,
https://fortress.wa.gov/ecy/waterresources/map/WCLSWebMap/WellConstructionMapSearc
h.aspx
Washington State Department of Transportation, 2016 Standard Specifications for Road,
Bridge and Municipal Construction
APPENDIX A
Project No. 1121161 -Preliminary Geotechnical Design Report
New King County DNRP Central Maintenance Facility
3005 NE 4th Street, Renton, Washington
Boring Logs
Figure A-1: Boring B-1
Figure A-2: Boring B-2
Figure A-3: Boring B-3
Figure A-4: Boring B-4
Figure A-5: Boring B-5
Figure A-6: Boring B-6
Boring Log Key to Symbols and Notes
Laboratory Test Reports
Figure A-7: B-1 @ 2.5 Feet
Figure A-8: B-2 @ 5.0 Feet
Figure A-9: B-3 @ 2.5 and 5.0 Feet
Figure A-10: B-4@5.0 and 10.0 Feet
Figure A-11: B-5@ 2.5 and 7.5 Feet
Figure A-12: B-6@ 7.5 Feet
Symbol Description
Strata symbols
FT]
Ed
ffl1l1
lliJillillillJ
[SJ
L2J
Crushed Surfacing
Well graded sand
Silty sand
Poorly graded sand
Poorly graded gravel
Misc. Symbols
T Boring terminated
Soil Samplers
KEY TO SYMBOLS
~ Standard penetration test
Notes:
1. Exploratory borings were drilled on April 13, 2017 using nominal 8-inch O.D.
continuous flight hollow stem auger.
2. A Mobile D-50 track-mounted drill rig was used to advance the auger.
3. SPT Tests were performed with an automatic trip hammer.
4. Where soil classifications changed between sampling intervals, the location
of the change noted on the boring logs was interpolated.
KING COUNTY MATERIALS LABORATORY
GEOTECHNICAL BORING LOGS
KING COUNTY DNRP MAINTENANCE FACILITY, RENTON, WASHINGTON
Particle Size Distribution Report
U.S. SIEVE OPENING IN INCHES U.S. STANDARD SIEVE NUMBERS HYDROMETER
1Y2 in. % in. 3/8 in. #140
6 in. 3 in. 2 in. 1 in. ~ Y2 in. #4 #10 #20 #30 #40 #60 #100 #200
100 I I I I r~11 I I I I I I I
90
80
'\
~
70 \
f\
a: 60 r\. w \ z u::: \. f-50 z
't~ w
0 a: w 40 Cl. " '-
30
r-... .... ,
'c ......... I'-<'\ 20 -,_
"
10
0
100 10 1 0.1 0.01 0.001
GRAIN SIZE -mm.
0/o +3" % Gravel %Sand % Fines
Coarse Fine Coarse Medium Fine Silt Clay
0 0.0 0.0 31.7 20.6 23.8 5.7 18.2
Source Sample# Depth/Elev. Date Sampled uses Material Description NM% LL PL
0 B-1 KC-17-318 2.5' to 4.0' 4-13-2017 SM Silty Sand with Gravel 4.1
Client KING Countv DNRP KING COUNTY
Project DNRP Maintenance Facility-Renton
Project No. 1122161 I Fiaure A-7 MATERIALS LABORATORY
Particle Size Distribution Report
U.S. SIEVE OPENING IN INCHES U.S. STANDARD SIEVE NUMBERS HYDROMETER
1% in. %in. 3/8 in. #140
6 in. 3 in. 2 in. 1 ·. Y2 in. #4 #10 #20 #30 #40 #60 #100 #200
100 I II I
\I
I I I I I I I I I
90 1
80 ~
\ 70 \
a: 60 LU " z u: ' I-50 z ' LU
0 \ a:
LU 40 0... '\
30 ' ~ ' 20 "-... ~
~ !'-,~ i-,... ._,._
10 -, ~ ~-
-'-'
0
100 10 1 0.1 0.01 . 0.001
GRAIN SIZE -mm.
0/o +3" % Gravel % Sand % Fines
Coarse Fine Coarse Medium Fine Silt Clay
0 0.0 15.1 45.7 16.1 12.5 5.4 5.2
Source Sample# Depth/Elev. Date Sampled uses Material Description NM% LL PL
0 B-2 KC-17-319 5.0' to 6.5' 4-13-2017 GP-GM Poorlv Graded Gravel with Silt and Sand 2.3
Client KING Countv DNRP KING COUNTY
Project DNRP Maintenance Facility -Renton
Project No. 1122161 I Fiqure A-8 MATERIALS LABORATORY
Particle Size Distribution Report
U.S. SIEVE OPENING IN INCHES U.S. STANDARD SIEVE NUMBERS HYDROMETER
1% in. %in. 3/8 in. #140
6 in. 3 in. 2 in. ~ 1 ·. Y2 in. #4 #10 #20 #30 #40 #60 #100 #200
100 I I r\ JII I II I I I I I I I
90 ~f
80 ~
\ \ 70 ~~ h
a: 60
>--r,,..11..
w ~ z ', u::: ....
I-50
'-....
z ', } w
() ' ~ a: w 40 CL ~,
::: -30 ', ...... "'C .......... ' .......... r-o....,_
20 ' ~
~ i-.,~
~
10 " -~
0
100 10 1 0.1 0.01 0.001
GRAIN SIZE -mm.
o/o +3" % Gravel % Sand % Fines
Coarse Fine Coarse Medium Fine Silt Clay
0 0.0 15.0 36.4 10.8 17.4 14.8 5.6
D 0.0 37.1 19.2 6.9 9.9 13.0 13.9
Source Sample# Depth/Elev. Date Sampled uses Material Description NM% LL PL
0 B-3 KC-17-320 2.5' to 4.0' 4-13-2017 GP-GM Poorlv Graded Gravel with Silt and Sand 5.1
D B-3 KC-17-321 5.0' to 6.5' 4-13-2017 GM Siltv Gravel with Sand 9.3
Client KING Countv DNRP KING COUNTY
Project DNRP Maintenance Facility-Renton
Project No. 1122161 I Fiaure A-9 MATERIALS LABORATORY
Particle Size Distribution Report
U.S. SIEVE OPENING IN INCHES U.S. STANDARD SIEVE NUMBERS HYDROMETER
1% in. %in. 3/8 in. #140
6 in. 3 in. 2 in. -1 ·. Y2 in. #4 #10 #20 #30 #40 #60 #100 #200
100 I I IT ~
~I
I I I I I I I I I
90 ' 80 t\ 70 \~ h
"-"r,..
cc 60 r\ w \ ", z u:: ~ I-50 z ........ w ~ ~ () n ' cc ' w 40 a.. ' "'' ~
30 \ '"'
~"'" ', 20 ....... "1 I\ :i........_ \: 10 c-... ......... .... _
--i:= ""'rl.... -~
0 ~
100 10 1 0.1 0.01 0.001
GRAIN SIZE -mm.
%+3" % Gravel % Sand % Fines
Coarse Fine Coarse Medium Fine Silt Clay
0 0.0 16.3 30.6 9.4 32.1 8.5 3.1
D 0.0 13.0 62.2 10.4 8.5 3.4 2.5
Source Sample# Depth/Elev. Date Sampled uses Material Description NM% LL PL
0 B-4 KC-17-322 5.0' to 6.5' 4-13-2017 SP Poorly Graded Sand with Gravel 3.2
D B-4 KC-17-323 10.0' to 11.5' 4-13-2017 GW Well-Graded Gravel with Sand 2.1
Client KING County DNRP KING COUNTY
Project DNRP Maintenance Facility -Renton
Project No. 1122161 I Fiqure A-10 MATERIALS LABORATORY
Particle Size Distribution Report
U.S. SIEVE OPENING IN INCHES U.S. STANDARD SIEVE NUMBERS HYDROMETER
1%in. %in. 3/8 in. #140
6 in. 3 in. 2 in. ~ 1 in. %in. #4 #10 #20 #30 #40 #60 #100 #200
100 I I T",, ~ l~l I I I I I I I
90 ' '
80 ~ \.
\ ~
70
\h
\ i\
a: 60 "' w '\1 z ~
u:: n
I-' z 50
~i\ "'~ w
() a: w 40 a.. 'f=\ "r-. .... ,
'r 30 l'I..
...... .......... "-ti ~ ...._..
20 "" ........... ..... ~ .. -~ -......
10 '-...._ ...,,_ --,_ ~-
0
100 10 1 0.1 0.01 0.001
GRAIN SIZE -mm.
0/o +3" % Gravel % Sand % Fines
Coarse Fine Coarse Medium Fine Silt Clay
0 0.0 0.0 29.9 18.2 20.7 16.6 14.6
D 0.0 15.0 49.2 14.2 12.8 4.7 4.1
Source Sample# Depth/Elev. Date Sampled uses Material Description NM% LL PL
0 B-5 KC-17-324 2.5' to 4.0' 4-13-2017 SM Silty Sand with Gravel 7.7
D B-5 KC-17-325 7.5' to 9.0' 4-13-2017 GW Well-Graded Gravel with Sand 2.9
Client KING County DNRP KING COUNTY
Project DNRP Maintenance Facility-Renton
Project No. 1122161 I Fiqure A-11 MATERIALS LABORATORY
Particle Size Distribution Report
U.S. SIEVE OPENING IN INCHES U.S. STANDARD SIEVE NUMBERS HYDROMETER
1% in. %in. 3/8 in. #140
6 in. 3 in. 2 in. -1 in. Y2 in. #4 #10 #20 #30 #40 #60 #100 #200
100 I I i\ I I I I I I I I I
90 \ 80 ~
i-. ...
70 Joo, ..._
~~ a: 60 ill "'~ z u:
I-50 L z '-<
ill \ 0 a: \ ill 40 0...
\
30 t
20 ~
"
10 ~
~ ..... -
~
0
100 10 1 0.1 0.01 0.001
GRAIN SIZE -mm.
0/o +3" % Gravel %Sand % Fines
Coarse Fine Coarse Medium Fine Silt Clay
0 0.0 20.8 9.9 5.3 37.8 20.8 5.4
Source Sample# Depth/Elev. Date Sampled uses Material Description NM% LL PL
0 B-6 KC-17-326 7.5' to 9.0' 4-13-2017 SP-SM Poorlv Graded Sand with Silt and Gravel 6.1
Client KING Countv DNRP KING COUNTY
Project DNRP Maintenance Facility -Renton
Project No. 1122161 I Fiaure A-12 MATERIALS LABORATORY
APPENDIX F
Report Limitations and Guidance
for Use
APPENDIX C
Report Limitations and
Guidelines for Use
ASPECT CONSULTING
REPORT LIMITATIONS AND GUIDELINES FOR
USE
This Report and Project-Specific Factors
Aspect Consulting, LLC (Aspect) considered a number of unique, project-specific factors
when establishing the Scope of Work for this project and report. You should not rely on
this report if it was:
•Not prepared for you
•Not prepared for the specific purpose identified in the Agreement
•Not prepared for the specific real property assessed
•Completed before important changes occurred concerning the subjectproperty, project or governmental regulatory actions
Geoscience Interpretations
The geoscience practices (geotechnical engineering, geology, and environmental science)
require interpretation of spatial information that can make them less exact than other
engineering and natural science disciplines. It is important to recognize this limitation in
evaluating the content of the report. If you are unclear how these "Report Limitations
and Use Guidelines" apply to your project or site, you should contact Aspect.
Reliance Conditions for Third Parties
This report was prepared for the exclusive use of the Client. No other party may rely on
the product of our services unless we agree in advance to such reliance in writing. This is
to provide our firm with reasonable protection against liability claims by third parties
with whom there would otherwise be no contractual limitations. Within the limitations of
scope, schedule, and budget, our services have been executed in accordance with our
Agreement with the Client and recognized geoscience practices in the same locality and
involving similar conditions at the time this report was prepared
Property Conditions Change Over Time
This report is based on conditions that existed at the time the study was performed. The
findings and conclusions of this report may be affected by the passage of time, by events
such as a change in property use or occupancy, or by natural events, such as floods,
earthquakes, slope instability, or groundwater fluctuations. If any of the described events
may have occurred following the issuance of the report, you should contact Aspect so
that we may evaluate whether changed conditions affect the continued reliability or
applicability of our conclusions and recommendations.
ASPECT CONSULTING
Discipline-Specific Reports Are Not Interchangeable
The equipment, techniques, and personnel used to perform a geotechnical or geologic
study differ significantly from those used to perform an environmental study and vice
versa. For that reason, a geotechnical engineering or geologic report does not usually
address any environmental findings, conclusions, or recommendations (e.g., about the
likelihood of encountering underground storage tanks or regulated contaminants).
Similarly, environmental reports are not used to address geotechnical or geologic
concerns regarding the subject property.
We appreciate the opportunity to perform these services. If you have any questions please
contact the Aspect Project Manager for this project.