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Updated Subsurface Exploration and Geotechnical Engineering Report
RENTON SCHOOL DISTRICT ELEMENTARY SCHOOL NO. 16
Renton, Washington
Prepared For:
RENTON SCHOOL DISTRICT
December 22, 2020
Project No. 20180398E002
Kirkland | Tacoma | Mount Vernon
425-827-7701 | www.aesgeo.com
December 22, 2020
Project No. 20180398E002
Renton School District
7812 South 124th Street
Seattle, Washington 98178
Attention: Ms. Traci Brewer-Rogstad
Subject: Updated Subsurface Exploration and Geotechnical Engineering Report
Renton School District Elementary School No. 16
Renton, Washington
Dear Ms. Brewer-Rogstad:
We are pleased to present this updated geotechnical engineering report for the referenced
project. This report summarizes the results of our subsurface exploration and presents
recommendations for design and construction of a new school at the site. An earlier version of
this report was prepared, dated November 23, 2019. This update incorporates changes to
Section 6.4, reflecting the new 2018 IBC codes.
We have enjoyed working with you on this study and are confident that the recommendations
presented in this report will aid in the successful completion of your project. If you should have
any questions or if we can be of additional help to you, please do not hesitate to call.
Sincerely,
ASSOCIATED EARTH SCIENCES, INC.
Kirkland, Washington
______________________________
Kurt D. Merriman, P.E.
Senior Principal Engineer
KDM/ld
20180398E002-4
UPDATED SUBSURFACE EXPLORATION AND
GEOTECHNICAL ENGINEERING REPORT
RENTON SCHOOL DISTRICT
ELEMENTARY SCHOOL NO. 16
Renton, Washington
Prepared for:
Renton School District
7812 South 124th Street
Seattle, Washington 98178
Prepared by:
Associated Earth Sciences, Inc.
911 5th Avenue
Kirkland, Washington 98033
425-827-7701
December 22, 2020
Project No. 20180398E002
Updated Subsurface Exploration and
Renton School District Elementary School No. 16 Geotechnical Engineering Report
Renton, Washington Project and Site Conditions
December 22, 2020 ASSOSCIATED EARTH SCIENCES, INC.
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I. PROJECT AND SITE CONDITIONS
1.0 INTRODUCTION
This report summarizes the results of our subsurface exploration and geotechnical engineering
study for the Renton Elementary School No. 16 project. Recommendations in this report are
based on a “Site Coordination Plan” by Hutteball + Oremus Architecture dated October 21,
2020 and an ALTA survey titled “Renton School District Chelan Ave. NE Project” by Terrane
dated October 12, 2020. The site location is shown on the “Vicinity Map,” Figure 1.
The approximate locations of explorations completed for this study are shown on the “Site and
Exploration Plan,” Figure 2. A Light Detection and Ranging (LIDAR)-based “Existing Site and
Exploration Plan” is included as Figure 3. Interpretive exploration logs and laboratory test
results are included in the Appendix. This report is based on the referenced plans. If project
plans are changed substantially, we should be allowed to review the recommendations in this
report and revise them if necessary.
1.1 Purpose and Scope
The purpose of our study is to provide subsurface exploration data and geotechnical
engineering recommendations for use during project design. Our study included a review of
selected available geologic literature, advancing 20 exploration borings, and performing
geologic studies to assess the type, thickness, distribution, and physical properties of the
subsurface sediments and shallow groundwater. Geotechnical engineering studies were
completed to formulate recommendations for geotechnical critical areas, site preparation,
grading, types of suitable foundations and floors, allowable foundation soil bearing pressure,
anticipated foundation and floor settlement, drainage considerations, and infiltration
feasibility. This report summarizes our fieldwork and offers recommendations based on our
present understanding of the project.
1.2 Authorization
Our study was authorized by means of a District purchase order. This report has been prepared
for the exclusive use of the Renton School District (RSD) for specific application to this project.
Within the limitations of scope, schedule, and budget, our services have been performed in
accordance with generally accepted geotechnical engineering and engineering geology
practices in effect in this area at the time our report was prepared. No other warranty, express
or implied, is made.
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Renton, Washington Project and Site Conditions
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2.0 PROJECT AND SITE DESCRIPTION
The subject site includes 11 residential parcels totaling approximately 12.78 acres in total area.
Until recently the project site was developed with homes and mature landscaping. The houses
were recently demolished and the majority of the landscaping removed. The site includes slope
areas highlighted by the City of Renton as potentially meeting criteria for treatment as
geotechnical critical areas. Geotechnical critical areas are discussed in detail later in this report.
We understand that a wetland has been delineated on the west side and in a low area along
Duvall Avenue NE in the northeast corner of the site.
The current project concept calls for construction of new elementary school buildings near the
center of the project site. A paved parking area is planned south of the school buildings, with
hard and soft surface play areas to the north. Wetland areas to the west will be left
undisturbed. Construction close to existing grade is expected, without deep excavation or thick
structural fill.
3.0 SUBSURFACE EXPLORATION
Our field study included advancing a total of 20 exploration borings across the site. Exploration
borings EB-1 through EB-8 were advanced on August 22, 2018, EB-9 through EB-14 were
advanced on September 27, 2019, and EB-15 through EB-20 were advanced on October 6,
2020. The conclusions and recommendations presented in this report are based on the
explorations completed for this study. The number, locations, and depths of our explorations
were completed within site and budgetary constraints. Our explorations were approximately
located in the field relative to known site features shown on Figures 2 and 3. Interpretive
exploration logs and laboratory test results are presented in the Appendix.
Because of the nature of exploratory work below ground, extrapolation of subsurface
conditions between field explorations is necessary. It should be noted that differing subsurface
conditions may sometimes be present due to the random nature of deposition and the
alteration of topography by past grading and/or filling. The nature and extent of any variations
between the field explorations may not become fully evident until construction. If variations
are observed at that time, it may be necessary to re-evaluate specific recommendations in this
report and make appropriate changes.
3.1 Exploration Borings
The exploration borings were completed by advancing hollow-stem auger tools with a
limited-access track-mounted drill rig. During the drilling process, samples were obtained at
generally 2.5- to 5-foot-depth intervals. The exploration borings were continuously observed
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and logged by a representative from our firm. The exploration logs presented in the Appendix
are based on the field logs, drilling action, and inspection of the samples secured.
Disturbed, but representative samples were obtained by using the Standard Penetration Test
(SPT) procedure in accordance with ASTM International (ASTM) D-1586. This test and sampling
method consists of driving a standard 2-inch, outside-diameter, split-barrel sampler a distance
of 18 inches into the soil with a 140-pound hammer free-falling 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. If a total of 50 is recorded within one 6-inch interval, the blow count is recorded as
the number of blows for the corresponding number of inches of penetration. The resistance, or
N-value, provides a measure of the relative density of granular soils or the relative consistency
of cohesive soils; these values are plotted on the attached exploration boring logs.
The samples obtained from the split-barrel sampler were classified in the field and
representative portions placed in watertight containers. The samples were then transported to
our laboratory for further visual classification and laboratory testing.
4.0 SUBSURFACE CONDITIONS
Subsurface conditions at the project site were inferred from the field explorations
accomplished for this study, visual reconnaissance of the site, and review of selected geologic
literature. The general distribution of geologic units is shown on the exploration logs. The
explorations typically encountered native materials consisting of medium dense grading to very
dense lodgement till sediments. Ten exploration borings encountered surficial existing fill to
depths of up to approximately 7 feet below the existing ground surface. Two explorations
(EB-10 and EB-11) encountered thin layers of fine sand interpreted as Vashon recessional
outwash. The northernmost exploration borings (EB-13 and EB-14) terminated at depths of
approximately 20.5 to 21.5 feet in stratified sediments that appear to represent lodgement till
to advance outwash transition sediments.
4.1 Stratigraphy
Grass/Topsoil/Forest Duff
A surficial layer of grass and organic topsoil was encountered at the location of each of the
exploration locations. This organic layer was approximately 6 inches thick or less at most
boring locations, and thicker at three locations. Observed topsoil thickness is shown on the
attached subsurface exploration logs.
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Renton, Washington Project and Site Conditions
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Due to their high organic content, these materials are not considered suitable for foundation,
roadway, or slab-on-grade floor support, or for use in a structural fill.
Fill
Existing fill was observed in exploration borings EB-3, EB-4, EB-10, EB-12, EB-13, EB-14, EB-15,
EB-18, EB-19, and EB-20 to depths of approximately 1.5 to 7 feet below existing ground level.
The observed existing fill consists of loose to medium dense silty to very silty sand with varying
amounts of gravel and includes some charcoal and other organic material. We anticipate that
additional existing fill will be encountered at the locations of former structures and buried
utilities.
Excavated existing fill material is suitable for reuse in structural fill applications if such reuse is
specifically allowed by project plans and specifications, if excessively organic and any other
deleterious materials are removed, and moisture content is adjusted to allow compaction to
the specified level and to a firm and unyielding condition. Based on our explorations completed
for this study, we estimate the observed existing fill was above optimum moisture content for
compaction purposes, and therefore may require drying during favorable weather prior to
compaction in structural fill applications.
Vashon Recessional Outwash
Exploration borings EB-10 and EB-11 encountered loose to medium dense sand, with variable
amounts of gravel and varying silt content interpreted as Vashon recessional outwash. Vashon
recessional outwash was deposited by meltwater streams from a receding glacier and is
typically not glacially consolidated.
Recessional outwash is suitable for support of paving and lightly-loaded structures with proper
preparation. Excavated recessional outwash soils are suitable for reuse in structural fill
applications if allowed by project specifications and if adjusted to a suitable moisture content
prior to compaction.
Vashon Lodgement Till
All of our explorations encountered typically medium dense grading to very dense, silty sand
with gravel interpreted as Vashon lodgement till. The lodgement till observed in our
explorations graded from medium dense to very dense with increasing depth. Lodgement till
was deposited at the base of an active ice sheet and was subsequently compacted by the
weight of the overlying glacial ice.
Lodgement till typically possesses high-strength and low-compressibility attributes that are
favorable for support of foundations, floor slabs, and paving with proper preparation.
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Renton, Washington Project and Site Conditions
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Lodgement till is silty and moisture-sensitive. In the presence of moisture contents above the
optimum moisture content for compaction purposes, lodgement till can be easily disturbed by
vehicles and earthwork equipment. Careful management of moisture-sensitive soils, as
recommended in this report, will be needed to reduce the potential for disturbance of wet
lodgement till soils and costs associated with repairing disturbed soils. Excavated lodgement till
sediments are suitable for reuse in structural fill applications if specifically allowed by project
specifications, and if moisture conditions are adjusted to allow compaction to a firm and
unyielding condition at the specified level. At the time of exploration the lodgement till
sediments were observed to be above optimum moisture content for compaction purposes and
would require drying during favorable dry site and weather conditions.
Vashon Advance Outwash Transition Sediments
Two of the exploration borings completed for this study (EB-13 and EB-14) encountered very
dense, weakly to moderately bedded sands with variable silt content and trace gravel
interpreted as advance outwash transitional sediments. Advance outwash was deposited by
meltwater streams from an advancing ice sheet and was subsequently compacted by the
overlying glacial ice. The term “transitional” is interpretative and indicates that the sediments
represent a gradation zone at the base of the lodgement till and the top of the Vashon advance
outwash.
Advance outwash is suitable for support of structural loads when prepared as recommended in
this report and can be an appropriate receptor for stormwater infiltration under some
circumstances. Advance outwash may contain a significant fine-grained fraction and can be
sensitive to excess moisture during placement in structural fill applications. Reuse of advance
outwash in structural fill applications is feasible if specifically allowed by project specifications
and is expected to require drying to achieve moisture contents within 1 to 2 percent of
optimum for compaction purposes.
4.2 Regional Geologic and Soil Map Review
We reviewed a regional geologic map (J.C. Yount, J.P. Minard, and G.R. Dembroff, 1993,
Geologic Map of Surficial Deposits in the Seattle 30’ by 60’ Quadrangle, Washington: U.S.
Geological Survey, Open-File Report 93-233, scale 1:100,000). The referenced map indicates
that the site is expected to be underlain at shallow depths by Vashon lodgement till. Our
on-site explorations and interpretations are generally consistent with the conditions depicted
on the referenced published map.
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Renton, Washington Project and Site Conditions
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4.3 Hydrology
Groundwater was not encountered in any of the explorations completed for this study at the
time of exploration. Although not encountered in our explorations, we expect shallow perched
groundwater to be present as “interflow” during the wetter season within existing fill,
recessional outwash, and the upper, weathered lodgement till sediments. Interflow occurs
when surface water infiltrates down through relatively permeable soils such as the fill and
recessional outwash sediments, and becomes trapped or “perched” atop a comparatively very
low-permeability barrier such as silty unweathered lodgement till. This perched water may
travel laterally above less-permeable strata. The duration and quantity of perched seepage will
largely depend on the soil grain-size distribution, topography, seasonal precipitation, on- and
off-site land usage, and other factors.
4.4 Laboratory Test Results
Two laboratory grain-size analyses were performed in accordance with ASTM procedures on
representative selected samples collected during our subsurface exploration for this project.
The tests were completed on samples of the lodgement till as part of our stormwater
infiltration feasibility assessment. The grain-size analyses test results are included in the
Appendix.
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Renton, Washington Geologic Hazards and Mitigations
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II. GEOLOGIC HAZARDS AND MITIGATIONS
The following discussion of potential geologic hazards is based on the geologic conditions as
observed and discussed herein.
5.0 SLOPE STABILITY HAZARDS AND RECOMMENDED MITIGATION
City of Renton critical areas regulations related to steep slopes are contained in Renton
Municipal Code (RMC) Section 4-3-050. The City provides an interactive GIS system 1 that shows
approximate locations of slopes that meet critical slope definitions included in the RMC. The
RMC provides mechanisms for:
• Using site-specific survey data in lieu of City GIS maps to determine the presence of
regulated slopes.
• Establishing prescriptive buffers for regulated slopes, and reducing prescriptive buffers
based on site-specific analysis.
• Modification of regulated slopes.
5.1 Sensitive Slopes
Based on the site survey, the site contains slopes that meet the RMC definition for Sensitive
Slopes. The Sensitive Slopes are located along the west side of the site adjacent to mapped
wetlands and are interpreted to be slopes that were created during previous earthwork. The
RMC does not require a buffer or structure setback for Sensitive Slopes (RMC 4-3-050G). The
project as currently proposed may require modification of Sensitive Slopes, which can be
allowed under the provisions of RMC 4-3-050J. In our opinion, site grading that is completed in
a manner consistent with the recommendations in this report will not result in increased risk of
slope instability on or offsite. If construction site Temporary Erosion and Sedimentation
Controls (TESCs) are implemented during construction in accordance with local standards of
practice, the project as currently proposed will not result in increased risks to the existing
wetlands as a result of slope instability or erosion, in our opinion.
5.2 Protected Slopes
Based on the site survey, the site does not contain Protected Slopes as defined in RMC
4-3-050G.5.a.ii.
1 https://rp.rentonwa.gov/Html5Public/Index.html?viewer=CORMaps
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6.0 SEISMIC HAZARDS AND RECOMMENDED MITIGATION
Earthquakes occur in the Puget Sound Lowland. The majority of these events are small and are
usually not felt by people. However, large earthquakes do occur as demonstrated by the most
recent 6.8-magnitude event on February 28, 2001 near Olympia, Washington, the 1965
6.5-magnitude event, and the 1949 7.2-magnitude event. The 1949 earthquake appears to
have been the largest in this area during recorded history. Evaluation of return rates indicates
that an earthquake of the magnitude between 5.5 and 6.0 is likely within a given 20-year
period.
Generally, there are four types of potential geologic hazards associated with large seismic
events: 1) surficial ground rupture, 2) seismically induced landslides, 3) liquefaction, and
4) ground motion. The potential for each of these hazards to adversely impact the proposed
project is discussed below.
6.1 Surficial Ground Rupture
We reviewed a map of possible geologic fault traces on the Washington State Division of
Geology and Earth Resources Interactive Geologic Map. The site is located approximately
0.8 miles south of the Seattle Fault Zone, the closest mapped fault zone to the project. The
potential for surface rupture due to seismic faulting is low in our opinion due to the distance
from the site to mapped faults.
6.2 Seismically Induced Landslides
It is our opinion that the potential risk of damage to the proposed development by seismically
induced slope failures is low during a design-level seismic event due to the presence of dense
and unsaturated native sediments observed at shallow depths below the site. No detailed
quantitative assessment of slope stability was completed, and none is warranted for the project
as currently proposed, in our opinion.
6.3 Liquefaction
Liquefaction is a process through which unconsolidated soil loses strength as a result of
vibrations, such as those which occur during a seismic event. During normal conditions, the
weight of the soil is supported by both grain-to-grain contacts and by the fluid pressure within
the pore spaces of the soil below the water table. Extreme vibratory shaking can disrupt the
grain-to-grain contact, increase the pore pressure, and result in a temporary decrease in soil
shear strength. The soil is said to be liquefied when nearly all of the weight of the soil is
supported by pore pressure alone. Liquefaction can result in deformation of the sediment and
settlement of overlying structures. Areas most susceptible to liquefaction include those areas
underlain by non-cohesive silt and sand with low relative densities, accompanied by a shallow
water table.
Updated Subsurface Exploration and
Renton School District Elementary School No. 16 Geotechnical Engineering Report
Renton, Washington Geologic Hazards and Mitigations
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A review of the City of Renton’s interactive GIS map indicates that a seismic hazard area exists
adjacent to the west of the project. Seismic hazard areas are associated with loose, saturated
granular soils that may experience liquefaction during a seismic event. Exploration borings on
the west part of the project site near the mapped seismic hazard area offsite encountered very
dense Vashon lodgement till near the surface. Lodgement till is not susceptible to liquefaction
during a seismic event. The site does not contain subsurface conditions that warrant treatment
as seismic hazard critical areas, in our opinion. No quantitative liquefaction analysis was
completed for this study, and none is warranted for the project as currently proposed, in our
opinion.
6.4 Ground Motion/Seismic Site Class (2018 International Building Code)
Structural design of the buildings should follow 2018 International Building Code (IBC)
standards. We recommend that the project be designed in accordance with Site Class “D” as
defined in Table 20.3-1 of American Society of Civil Engineers (ASCE) 7 - Minimum Design Loads
for Buildings and Other Structures. As requested, we looked up seismic design values Ss and S1
(IBC 1613.2.1) using the site latitude and longitude and published maps at
https://seismicmaps.org/. The published value of Ss is 1.406, and S1 is 0.481.
6.5 Erosion Control
The RMC defines a low erosion hazard as an area with soils characterized by the Natural
Resource Conservation Service as having slight or moderate erosion potential, and a slope less
than 15 percent. A high erosion hazard is defined as having severe or very severe erosion
potential, and a slope more than 15 percent. These definitions are incomplete in that the site
contains slopes that do not fit either definition. In our opinion the site contains areas that meet
the spirit of the definition for low erosion hazard areas. The following recommendations
summarize local standards of practice for TESC on construction sites, and are expected to
provide adequate mitigation of erosion potential during construction.
Project plans should include implementation of temporary erosion controls in accordance with
local standards of practice. Control methods should include limiting earthwork to seasonally
drier periods, typically April 1 to October 31, use of perimeter silt fences, and straw mulch in
exposed areas. Removal of existing vegetation should be limited to those areas that are
required to construct the project, and new landscaping and vegetation with equivalent erosion
mitigation potential should be established as soon as possible after grading is complete. During
construction, surface water should be collected as close as possible to the source to minimize
silt entrainment that could require treatment or detention prior to discharge. Timely
implementation of permanent drainage control measures should also be a part of the project
plans, and will help reduce erosion and generation of silty surface water onsite. Because the
site is larger than one acre, testing and reporting of stormwater pH and turbidity will be
required during construction.
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III. DESIGN RECOMMENDATIONS
7.0 INTRODUCTION
Our exploration indicates that from a geotechnical engineering standpoint the proposed school
construction project is feasible if the recommendations in this report are implemented.
A portion of the site is underlain by existing fill which necessitates remedial preparation prior to
constructing new roads and buildings. Observed fill thicknesses at exploration locations are
depicted on Figure 2. Existing fill that is expected around former structures and buried utilities
will also need to be removed and recompacted at the time of construction. The following
report sections provide additional recommendations regarding site preparation, grading,
foundations, floor support, drainage, and infiltration feasibility.
8.0 SITE PREPARATION
Site preparation of building and paving areas should include removal of all grass, trees, brush,
and any other deleterious materials. We recommend that any remaining demolition debris,
septic systems, or other similar structures that are discovered be decommissioned and
removed in accordance with applicable regulations. Buried utilities should be removed from
foundation areas and should be abandoned in place or removed from below planned new
paving. Any depressions below planned final grades caused by demolition activities should be
backfilled with structural fill, as discussed under the “Structural Fill” section of this report.
Existing topsoil and forest duff should be stripped from structural areas. The actual observed
in-place depth of grass and topsoil at the exploration locations is presented on the exploration
logs in the Appendix. After stripping, remaining roots and stumps should be removed from
structural areas. All soils disturbed by stripping and grubbing operations should be
recompacted as described below for structural fill.
Once stripping is complete, existing fill should be addressed. Existing fill below new buildings
should be removed and replaced with structural fill. Below areas of planned paving, existing fill
may be left in place if it is free of organic and other deleterious materials, and is compactable to
a firm and unyielding condition at 95 percent or more of the modified Proctor maximum dry
density (ASTM D-1557).
Once excavation to subgrade elevation is complete, the resulting surface should be proof-rolled
with a loaded dump truck or other suitable equipment. Any soft, loose, yielding areas or areas
exposing excessively organic material should be excavated to exposed suitable bearing soils.
The subgrade should then be compacted to at least 95 percent of the modified Proctor
maximum dry density, as determined by the ASTM D-1557 test procedure. Structural fill can
then be placed to achieve desired grades, if needed.
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8.1 Temporary Cut Slopes
In our opinion, stable construction slopes should be the responsibility of the contractor and
should be determined during construction. For estimating purposes, however, temporary,
unsupported cut slopes can be planned at 1.5H:1V (Horizontal:Vertical) in unsaturated existing
fill and recessional outwash. Temporary slopes of 1.0H:1V can be planned in unsaturated
lodgement till sediments.
These slope angles are for areas where groundwater seepage is not present at the faces of the
slopes, which may require temporary dewatering in the form of pumped sumps or other
measures. If ground or surface water is present when the temporary excavation slopes are
exposed, flatter slope angles may be required. As is typical with earthwork operations, some
sloughing and raveling may occur, and cut slopes may have to be adjusted in the field.
In addition, WISHA/OSHA regulations should be followed at all times.
8.2 Site Disturbance
Most of the on-site soils contain fine-grained material, which makes them moisture-sensitive
and subject to disturbance when wet. The contractor must use care during site preparation
and excavation operations so that the underlying soils are not softened. If disturbance occurs,
the softened soils should be removed and the area brought to grade with structural fill.
8.3 Winter Construction
The existing fill material, as well as the lodgement till and recessional outwash sediments
contain substantial silt and are considered highly moisture-sensitive. Soils excavated onsite will
likely require drying during favorable dry weather conditions to allow their reuse in structural
fill applications. Care should be taken to seal all earthwork areas during mass grading at the
end of each workday by grading all surfaces to drain and sealing them with a smooth-drum
roller. Stockpiled soils that will be reused in structural fill applications should be covered
whenever rain is possible.
If winter construction is expected, crushed rock fill could be used to provide construction
staging areas where exposed soil is present. The stripped subgrade should be observed by the
geotechnical engineer, and should then be covered with a geotextile fabric, such as Mirafi 500X
or equivalent. Once the fabric is placed, we recommend using a crushed rock fill layer at least
10 inches thick in areas where construction equipment will be used.
9.0 STORMWATER INFILTRATION FEASIBILITY
Our explorations completed for this study encountered existing fill and recessional outwash
sediments underlain by dense, silty Vashon lodgement till sediments. Existing fill is not a
suitable infiltration receptor due to its variable density, silt, and organic content. Two borings
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encountered a thin deposit of recessional outwash at shallow depths. Recessional outwash can
be a suitable stormwater infiltration receptor, however the deposits encountered range from
2.5 to 5 feet in thickness and do not appear laterally or vertically extensive enough to support
infiltration. Lodgement till is not a suitable infiltration receptor due to its high density and silt
content. In our opinion, shallow infiltration at this site using conventional strategies such as
infiltrating rain gardens and infiltration vaults is infeasible due to the dense, silty soils at
shallow depths across the site. Deep infiltration using strategies such as pit drains or
Underground Injection Control (UIC) wells may be feasible, but will require further exploration
to determine depth and extent of infiltration receptors at depth.
10.0 STRUCTURAL FILL
All references to structural fill in this report refer to subgrade preparation, fill type, placement,
and compaction of materials, as discussed in this section. If a percentage of compaction is
specified under another section of this report, the value given in that section should be used.
For backfill of buried utilities in the right-of-way, the backfill should be placed and compacted in
accordance with City of Renton codes and standards.
After stripping, planned excavation, and any required overexcavation have been performed to
the satisfaction of the geotechnical engineer/engineering geologist, the surface of the exposed
ground should be recompacted to a firm and unyielding condition. If the subgrade contains too
much moisture, adequate recompaction may be difficult or impossible to obtain, and should
probably not be attempted. In lieu of recompaction, the area to receive fill should be blanketed
with washed rock or quarry spalls to act as a capillary break between the new fill and the wet
subgrade. Where the exposed ground remains soft and further overexcavation is impractical,
placement of an engineering stabilization fabric may be necessary to prevent contamination of
the free-draining layer by silt migration from below.
After recompaction of the exposed ground is tested and approved, or a free-draining rock
course is laid, structural fill may be placed to attain desired grades. Structural fill is defined as
non-organic soil, acceptable to the geotechnical engineer, placed in maximum 8-inch loose lifts,
with each lift being compacted to 95 percent of ASTM D-1557. The top of the compacted fill
should extend horizontally outward a minimum distance of 3 feet beyond the locations of the
perimeter footings or roadway edges before sloping down at a maximum angle of 2H:1V.
The contractor should note that any proposed fill soils should be evaluated by Associated Earth
Sciences, Inc. (AESI) prior to their use in fills. This would require that we have a sample of the
material at least 72 hours in advance to perform a Proctor test and determine its field
compaction standard.
Soils in which the amount of fine-grained material (smaller than the No. 200 sieve) is greater
than approximately 5 percent (measured on the minus No. 4 sieve size) should be considered
Updated Subsurface Exploration and
Renton School District Elementary School No. 16 Geotechnical Engineering Report
Renton, Washington Design Recommendations
December 22, 2020 ASSOSCIATED EARTH SCIENCES, INC.
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moisture-sensitive. The existing fill and native soils are estimated to contain more than
5 percent fine-grained material. Existing fill and lodgement till soils are estimated to have
substantially more than 5 percent fine-grained material. Use of moisture-sensitive soil in
structural fills should be limited to favorable dry weather and dry subgrade conditions.
Construction equipment traversing the site when the soils are wet can cause considerable
disturbance.
If fill is placed during wet weather or if proper compaction cannot be obtained, a select, import
material consisting of a clean, free-draining gravel and/or sand should be used. Free-draining
fill consists of non-organic soil, with the amount of fine-grained material limited to 5 percent by
weight when measured on the minus No. 4 sieve fraction, and at least 25 percent retained on
the No. 4 sieve.
Excavated existing fill is suitable for reuse in structural fill applications if such reuse is
specifically allowed by project plans and specifications, if excessively organic and any other
deleterious materials are removed, and moisture content is adjusted to allow compaction to
the specified level and to a firm and unyielding condition. The existing fill and native soils we
encountered in our explorations ranged in moisture content from moist to wet. In order to
reuse excavated on-site soils in structural fill applications, it will be necessary to
moisture-condition wet site soils by aeration and drying during favorable dry weather
conditions. Alternatives to drying site soils include using imported granular soils suitable for
use in structural fill, or treating wet soils with Portland cement.
11.0 FOUNDATIONS
The following sections provide two sets of foundation support geotechnical recommendations,
one for building foundations and one for stormwater vault foundations.
11.1 Building Foundations
Building areas should be prepared in accordance with the “Site Preparation” and “Structural
Fill” sections of this report. Conventional continuous spread footings may be used for building
support when founded either directly on the undisturbed, dense to very dense natural
sediments, or on compacted structural fill over suitable natural sediments. We recommend
that an allowable foundation soil bearing pressure of 3,500 pounds per square foot (psf) be
utilized for design purposes, including both dead and live loads. An increase of one-third may
be used for short-term wind or seismic loading. All footings must penetrate to the prescribed
bearing stratum and no footing should be founded in or above loose, organic, or fill soils.
11.2 Stormwater Vault Foundations
We anticipate that the project will include a below-grade, cast-in-place stormwater detention
vault. Because the detention vault will be constructed below grade and therefore likely below
Updated Subsurface Exploration and
Renton School District Elementary School No. 16 Geotechnical Engineering Report
Renton, Washington Design Recommendations
December 22, 2020 ASSOSCIATED EARTH SCIENCES, INC.
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any existing weak fill soils, and because the vault has substantial span requirements, a higher
allowable foundation soil bearing pressure is appropriate for design of vault foundations. These
recommendations are applicable only to the stormwater vault; recommendations presented
above should be used for design of building foundations.
Conventional continuous spread footings may be used for stormwater vault support when
founded on dense to very dense natural sediments. We recommend that an allowable
foundation soil bearing pressure of 5,000 psf be utilized for design purposes, including both
dead and live loads. An increase of one-third may be used for short-term wind or seismic
loading. All footings must penetrate to the prescribed bearing stratum and no footing should
be founded in or above loose, organic, or fill soils.
11.3 Conditions, Recommendations, and Settlement Estimate Applicable to All Foundations
It should be noted that the area bounded by lines extending downward at 1H:1V from any
footing must not intersect another footing or filled area. In addition, a 1.5H:1V line extending
down from any footing must not daylight because sloughing or raveling may eventually
undermine the footing. Thus, footings should not be placed near the edge of steps or cuts in
the bearing soils.
Anticipated settlement of footings founded as recommended above should be less than 1 inch
with differential settlement one-half of the anticipated total settlement. Most of this
movement should occur during initial dead load applications. However, disturbed soil not
removed from footing excavations prior to concrete placement could result in increased
settlements. All footing areas should be observed by AESI prior to placing concrete to verify
that the design bearing capacity of the soils has been attained and that construction conforms
to the recommendations contained in this report. Such observation may be required by the
City of Renton. A perimeter foundation drain system should be provided as discussed under
the “Foundation Drainage Considerations” section of this report.
The contractor must use care during site preparation and excavation operations so that the
underlying soils are not softened. If disturbance occurs the softened soils should be removed
and foundations extended down to competent natural soil. Once the base of the excavation is
reached, consideration should be given to “armoring” the exposed subgrade with a thin layer of
rock to provide a working surface during foundation construction. We recommend a 6-inch
layer of crushed rock for this purpose.
11.4 Foundation Drainage Considerations
Building and stormwater vault foundations should be provided with foundation drains. Drains
should consist of rigid, perforated, polyvinyl chloride (PVC) pipe placed at footing subgrade
elevation and surrounded by washed pea gravel. The drains should be constructed with
sufficient gradient to allow gravity discharge away from the proposed structures. Roof and
Updated Subsurface Exploration and
Renton School District Elementary School No. 16 Geotechnical Engineering Report
Renton, Washington Design Recommendations
December 22, 2020 ASSOSCIATED EARTH SCIENCES, INC.
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surface runoff should not discharge into footing drain systems, but should be handled by a
separate, rigid, tightline drain. In planning, exterior grades adjacent to walls should be sloped
downward away from the proposed structures to achieve surface drainage. If it is not possible
to place a footing drain at the base of the stormwater vault footings, the vault should be
constructed to resist lateral pressure imposed by saturated soils and hydrostatic pressure as
recommended in Section 13.0 of this report.
12.0 FLOOR SUPPORT
After completion of recommendations in the “Site Preparation” section of this report, floor
slabs can be supported on medium dense to very dense native soils or on new structural fill.
Floor slabs should be cast atop a minimum of 4 inches of clean, washed, crushed rock, or pea
gravel to act as a capillary break. Areas of subgrade that are disturbed (loosened) during
construction should be compacted to a non-yielding condition prior to placement of capillary
break material. Floor slabs should also be protected from dampness by an impervious moisture
barrier at least 10 mils thick. The moisture barrier should be placed between the capillary
break material and the concrete slab.
13.0 FOUNDATION WALLS
13.1 Building Foundation Walls
The following recommendations may be applied to conventional walls up to 8 feet tall. We
should be allowed to offer situation-specific input for taller walls. All backfill behind foundation
walls or around foundation units should be placed as per our recommendations for structural
fill and as described in this section of the report. Horizontally backfilled walls, which are free to
yield laterally at least 0.1 percent of their height, may be designed to resist lateral earth
pressure represented by an equivalent fluid equal to 35 pounds per cubic foot (pcf). Fully
restrained, horizontally backfilled, rigid walls that cannot yield should be designed for an
equivalent fluid of 50 pcf. Walls with sloping backfill up to a maximum gradient of 2H:1V should
be designed using an equivalent fluid of 55 pcf for yielding conditions or 75 pcf for fully
restrained conditions. If parking areas are adjacent to walls, a surcharge equivalent to 2 feet of
soil should be added to the wall height in determining lateral design forces.
As required by the 2018 IBC, retaining wall design should include a seismic surcharge pressure
in addition to the equivalent fluid pressures presented above. Considering the site soils and the
recommended wall backfill materials, we recommend a seismic surcharge pressure of 5H and
10H psf, where H is the wall height in feet for the “active” and “at-rest” loading conditions,
respectively. The seismic surcharge should be modeled as a rectangular distribution with the
resultant applied at the midpoint of the walls.
Updated Subsurface Exploration and
Renton School District Elementary School No. 16 Geotechnical Engineering Report
Renton, Washington Design Recommendations
December 22, 2020 ASSOSCIATED EARTH SCIENCES, INC.
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The lateral pressures presented above are based on the conditions of a uniform backfill
consisting of excavated on-site soils, or imported structural fill compacted to 90 percent of
ASTM D-1557. A higher degree of compaction is not recommended, as this will increase the
pressure acting on the walls. A lower compaction may result in settlement of the slab-on-grade
or other structures supported above the walls. Thus, the compaction level is critical and must
be tested by our firm during placement. Surcharges from adjacent footings or heavy
construction equipment must be added to the above values. Perimeter footing drains should
be provided for all retaining walls, as discussed under the “Drainage Considerations” section of
this report.
It is imperative that proper drainage be provided so that hydrostatic pressures do not develop
against the walls. This would involve installation of a minimum 1-foot-wide blanket drain to
within 1 foot of finish grade for the full wall height using imported, washed gravel against
the walls.
13.2 Stormwater Vault Foundation Walls
Stormwater vaults may be designed in accordance with lateral earth pressure and drainage
recommendations as described above for building walls, except as follows:
• If it is not possible to place a footing drain at the base of the detention vault, we
recommend installing a footing drain as deep as possible depending on footing drain
discharge options that are available.
• Any location where vault walls extend below drain elevation should be structurally
designed for saturated conditions below the elevation of the drain.
• Under saturated conditions, active lateral earth pressure should be assumed to be
80 pcf expressed as an equivalent fluid, and at-rest (restrained) lateral earth pressure
should be assumed to be 90 pcf.
• For detention vault drainage, the use of composite drain mats such as Miradrain is
acceptable in lieu of the washed rock drainage blanket described in Section 11.4 of this
report. Drainage mats should be continuous with and freely communicate with the
footing drain, and should be incorporated and installed in accordance with the
manufacturer’s recommendations.
13.3 Passive Resistance and Friction Factors
Lateral loads can be resisted by friction between the foundation and the natural soils or
supporting structural fill soils, and by passive earth pressure acting on the buried portions of
the foundations. The foundations must be backfilled with structural fill and compacted to
at least 95 percent of the maximum dry density to achieve the passive resistance provided
below. We recommend the following allowable design parameters:
Updated Subsurface Exploration and
Renton School District Elementary School No. 16 Geotechnical Engineering Report
Renton, Washington Design Recommendations
December 22, 2020 ASSOSCIATED EARTH SCIENCES, INC.
BWG/ld - 20180398E002-4 Page 17
• Passive equivalent fluid = 250 pcf
• Coefficient of friction = 0.30
14.0 PAVEMENT RECOMMENDATIONS
We anticipate that project plans may include construction of new paved parking lots and access
roads. At this time we do not anticipate that new paving will be completed on public streets.
If new paving is planned on public streets we should be allowed to make situation-specific
paving recommendations.
After the area to be paved is stripped, any organic soils are removed, and the soils are
recompacted, the area should be proof-rolled with a loaded truck under the observation of
AESI. Any soft, wet, organic, or yielding areas should be repaired as recommended during
construction. If warranted, engineering stabilization fabric, such as Mirafi 500X (or equivalent),
should be placed over the subgrade with the edges overlapped in accordance with the
manufacturer’s recommendations. Following subgrade preparation, clean, free-draining
structural fill should be placed over the fabric and compacted to 95 percent of ASTM D-1557.
Where fabric is exposed, spreading should be performed such that the dozer remains on the fill
material and is not allowed to operate on uncovered fabric. When 12 inches of fill has been
placed, the fabric should be proof-rolled with a loaded dump truck to pretension the fabric and
identify soft spots in the fill. Upon completing the proof-rolling operation, additional structural
fill should be placed and compacted to attain desired grades.
For driveways and private paving serving passenger cars, we recommend a paving section
consisting of 3 inches of Class ½-inch HMA underlain by 4 inches of crushed surfacing base
course (CSBC). Alternatively asphalt treated base (ATB) or Class ¾-inch HMA could be used for
construction access followed by repair of any construction damage and final surfacing. If this
alternative is used, we recommend a minimum of 2 inches of CSBC to serve as a working
surface and a minimum of 3 inches of ATB. Final surfacing should consist of 2 inches of
Class ½-inch HMA after any construction damage has been repaired.
Paving for heavy traffic areas such as bus lanes, fire lanes, and access for garbage and food
service trucks should consist of 4 inches of Class ½-inch HMA above 6 inches of crushed rock
base. If an ATB section is desired, we recommend a 2-inch-thick working surface of crushed
rock, topped by 4 inches of ATB and 3 inches of Class ½-inch HMA.
15.0 PROJECT DESIGN AND CONSTRUCTION MONITORING
We are available to provide additional geotechnical consultation as the project design develops
and possibly changes from that upon which this report is based. We recommend that AESI
perform a geotechnical review of the plans prior to final design completion. In this way,
geotechnical recommendations may be properly interpreted and implemented in the design.
Updated Subsurface Exploration and
Renton School District Elementary School No. 16 Geotechnical Engineering Report
Renton, Washington Design Recommendations
December 22, 2020 ASSOSCIATED EARTH SCIENCES, INC.
BWG/ld - 20180398E002-4 Page 18
We are also available to provide construction monitoring services during construction of the
infiltration facilities. The infiltration performance depends on verification of anticipated
subsurface conditions, proper site preparation, backfill quality, 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. Construction monitoring services are not part of the
current scope of work. If these services are desired, please let us know and we will prepare a
cost proposal.
We have enjoyed working with you on this study and are confident that these
recommendations will aid in the successful completion of your project. If you should have any
questions or require further assistance please do not hesitate to call.
Sincerely,
ASSOCIATED EARTH SCIENCES, INC.
Kirkland, Washington
______________________________
Charles R. Christopher, G.I.T.
Senior Staff Geologist
______________________________
Bruce W. Guenzler, L.E.G. Kurt D. Merriman, P.E.
Senior Associate Geologist Senior Principal Engineer
Attachments: Figure 1: Vicinity Map
Figure 2: Site and Exploration Plan
Figure 3: Existing Site and Exploration Plan
Appendix: Exploration Logs
Laboratory Testing Results
DATA SOURCES / REFERENCES:
USGS: 7.5' SERIES TOPOGRAPHIC MAPS, ESRI/I-CUBED/NGS 2013
KING CO: STREETS, CITY LIMITS, PARCELS, PARKS 3/20
LOCATIONS AND DISTANCES SHOWN ARE APPROXIMATE
VICINITY MAP
RENTON SD ELEMENTARY NO. 16
RENTON, WASHINGTON
20180398E002 11/20 1
KING COUNTY
KING COUNTY
KING COUNTY
NEWCASTLE
RENTON
McKnight
Middle
School
Sierra Heights
Elementary
School
Highlands
Elementary
School Renton
Technical
College
Honey
Dew
Elementary School
Maplewood Heights
Elementary School
Hazen High
School
Apollo
Elementary
School
May Valley
Park
Maplewood
Park
Maplewood
Park
May Creek
Park
May Creek
Park
May Creek
Park
Cougar
Mountain
Regional
Wildland Park
0 2000
Feet
PROJ NO.
NOTE: BLACK AND WHITE
REPRODUCTION OF THIS COLOR
ORIGINAL MAY REDUCE ITS
EFFECTIVENESS AND LEAD TO
INCORRECT INTERPRETATION DATE:FIGURE:\\kirkfile2\gis\GIS_Projects\aaY2018\180398 Renton SD Chelan Av\mxd\20180398E002 F1 VM_RSD_Chelan.aprx | 20180398E002 F1 VM_RSD_Chelan | 11/9/2020 11:19¥
¥
¥
¬«
¬«900
!(Duvall Ave NENE 12th St
DuvallPlNEChelan Ave NEKing County
SITE
EB-1, 0ft
EB-2, 0ftEB-3, 7ft
EB-4, 7ft
EB-5, 0ft
EB-6, 0ft
EB-7, 0ft
EB-8, 0ft
EB-9, 0ft
EB-10, 2ft
EB-11, 0ft
EB-12, 2ft
EB-13, 3ft
EB-14, 2ft
EB-15, 6.5ft
EB-16, 0ft
EB-17, 0ft
EB-18, 3ft
EB-19, 5.5ft
EB-20, 1.5ft
PROJ NO.
NOTE: BLACK AND WHITE
REPRODUCTION OF THIS COLOR
ORIGINAL MAY REDUCE ITS
EFFECTIVENESS AND LEAD TO
INCORRECT INTERPRETATION DATE:FIGURE:\\kirkfile2\gis\GIS_Projects\aaY2018\180398 Renton SD Chelan Av\mxd\20180398E002 F2 SP_RSDChelan.aprx | 20180398E002 F2 SP_RSDChelan | 11/9/2020 11:25 AMDATA SOURCES / REFERENCES:
HUTTEBALL + OREMUS ARCHITECTURE, NEW ELEMENTARY
SCHOOL #16, SITE COORDINATION PLAN, G0.20, 10/21/20
KING CO: PARCELS, 3/20
LOCATIONS AND DISTANCES SHOWN ARE APPROXIMATE
0 150
Feet
SITE AND
EXPLORATION PLAN
RENTON SD ELEMENTARY NO. 16
RENTON, WASHINGTON
20180398E002 11/20 2
LEGEND
SITE
EXPLORATION BORING, DEPTH OF FILL
NE 10th St Duvall Ave NEAnacortesAveNENE12thSt
Chelan Ave NEEB-1
EB-2EB-3 EB-4
EB-5
EB-6
EB-7EB-8
EB-9
EB-10
EB-11
EB-12
EB-13EB-14
EB-15
EB-16
EB-17
EB-18
EB-19
EB-20
400
410 410410
400
430440
4104504104
1
0
4404
5
0
400
400440410
4104604104104504404204
3
0
PROJ NO.
NOTE: BLACK AND WHITE
REPRODUCTION OF THIS COLOR
ORIGINAL MAY REDUCE ITS
EFFECTIVENESS AND LEAD TO
INCORRECT INTERPRETATION DATE:FIGURE:\\kirkfile2\gis\GIS_Projects\aaY2018\180398 Renton SD Chelan Av\mxd\20180398E002 F3 Lidar_RSDChelan.aprx | 20180398E002 F3 Lidar_RSDChelan | 11/5/2020 2:45DATA SOURCES / REFERENCES:
PSLC: KING COUNTY 2016, GRID CELL SIZE IS 3'.
DELIVERY 1 FLOWN 2/24/16 - 3/28/16
CONTOURS FROM LIDAR
KING CO: STREETS, PARCELS, 3/20
LOCATIONS AND DISTANCES SHOWN ARE APPROXIMATE
0 200
Feet
EXISTING SITE AND
EXPLORATION PLAN
RENTON SD ELEMENTARY NO. 16
RENTON, WASHINGTON
20180398E002 11/20 3
LEGEND
SITE
EXPLORATION BORING
PARCEL
CONTOUR 10 FT
CONTOUR 2 FT
APPENDIX
Exploration Logs
Laboratory Testing Results
14
28
50
35
50/3"
50/1"
S-1
S-2
S-3
Bottom of exploration boring at 12.6 feet
No groundwater encountered.
Grass / Topsoil
Vashon Lodgement Till
Moist, gray with some oxidation, very silty, gravelly, fine to medium SAND;
unsorted (SM).
Becomes gray.
No recovery due to rock.
1 of 1
NAVD 88
DV2" OD Split Spoon Sampler (SPT)
3" OD Split Spoon Sampler (D & M)Water LevelProject Name
CJKWater Level ()Approved by:
30
Blows/Foot
Samples~426
5
10
15
20
EB-1
Ring Sample
No RecoveryGraphic 10 Other TestsHole Diameter (in)
DESCRIPTION
Driller/Equipment
Blows/6"Exploration Boring
Water Level at time of drilling (ATD)
Renton School District Elementary School No. 16
M - Moisture
Project Number
20
Renton, WA
Date Start/Finish
CompletionLocation
Sheet
Depth (ft)S
T
Exploration Number
20180398E002
8/22/18,8/22/18
Logged by:
Shelby Tube Sample
140# / 30"
Geologic Drill / Mini Track
Well Ground Surface Elevation (ft)
Grab SampleSymbol 5 inches
40
Datum
Hammer Weight/Drop
Sampler Type (ST):AESIBOR 20180398E002.GPJ November 18, 202078
5050/3"
5050/1"
19
42
40
22
50/6"
38
29
38
S-1
S-2
S-3
Bottom of exploration boring at 14 feet
No groundwater encountered.
Grass / Topsoil
Vashon Lodgement Till
Moist, oxidized gray, very silty, gravelly, fine to medium SAND; unsorted
(SM).
Becomes gray.
Becomes very moist.
1 of 1
NAVD 88
DV2" OD Split Spoon Sampler (SPT)
3" OD Split Spoon Sampler (D & M)Water LevelProject Name
CJKWater Level ()Approved by:
30
Blows/Foot
Samples~422
5
10
15
20
EB-2
Ring Sample
No RecoveryGraphic 10 Other TestsHole Diameter (in)
DESCRIPTION
Driller/Equipment
Blows/6"Exploration Boring
Water Level at time of drilling (ATD)
Renton School District Elementary School No. 16
M - Moisture
Project Number
20
Renton, WA
Date Start/Finish
CompletionLocation
Sheet
Depth (ft)S
T
Exploration Number
20180398E002
8/22/18,8/22/18
Logged by:
Shelby Tube Sample
140# / 30"
Geologic Drill / Mini Track
Well Ground Surface Elevation (ft)
Grab SampleSymbol 5 inches
40
Datum
Hammer Weight/Drop
Sampler Type (ST):AESIBOR 20180398E002.GPJ November 18, 202082
5050/6"
67
4
3
5
50/6"
20
26
40
S-1
S-2
S-3
Bottom of exploration boring at 14 feet
No groundwater encountered.
Grass / Topsoil
Fill
Slightly moist to dry, brown to dark brown, very silty, fine SAND, trace
gravel, trace charcoal and other organics (SM).
Moist, grayish brown, silty, fine to medium SAND, some gravel (SM).
Vashon Lodgement Till
Driller notes hard drilling at 7 feet.
Moist, gray, very silty, fine to medium SAND, some gravel; unsorted (SM).
Moist, oxidized gray, very silty, fine SAND, trace gravel; unsorted (SM).
1 of 1
NAVD 88
DV2" OD Split Spoon Sampler (SPT)
3" OD Split Spoon Sampler (D & M)Water LevelProject Name
CJKWater Level ()Approved by:
30
Blows/Foot
Samples~414
5
10
15
20
EB-3
Ring Sample
No RecoveryGraphic 10 Other TestsHole Diameter (in)
DESCRIPTION
Driller/Equipment
Blows/6"Exploration Boring
Water Level at time of drilling (ATD)
Renton School District Elementary School No. 16
M - Moisture
Project Number
20
Renton, WA
Date Start/Finish
CompletionLocation
Sheet
Depth (ft)S
T
Exploration Number
20180398E002
8/22/18,8/22/18
Logged by:
Shelby Tube Sample
140# / 30"
Geologic Drill / Mini Track
Well Ground Surface Elevation (ft)
Grab SampleSymbol 5 inches
40
Datum
Hammer Weight/Drop
Sampler Type (ST):AESIBOR 20180398E002.GPJ November 18, 202088
5050/6"
66
8
9
14
13
15
17
22
22
26
S-1
S-2
S-3
Bottom of exploration boring at 14 feet
No groundwater encountered.
Grass / Topsoil
Fill
Moist, oxidized gray, very silty, fine to medium SAND, some gravel, trace
charcoal (SM).
Vashon Lodgement Till
Driller notes hard drilling at 7 feet.
Moist, gray, very silty, fine to medium SAND, some gravel; unsorted (SM).
As above.
1 of 1
NAVD 88
DV2" OD Split Spoon Sampler (SPT)
3" OD Split Spoon Sampler (D & M)Water LevelProject Name
CJKWater Level ()Approved by:
30
Blows/Foot
Samples~429
5
10
15
20
EB-4
Ring Sample
No RecoveryGraphic 10 Other TestsHole Diameter (in)
DESCRIPTION
Driller/Equipment
Blows/6"Exploration Boring
Water Level at time of drilling (ATD)
Renton School District Elementary School No. 16
M - Moisture
Project Number
20
Renton, WA
Date Start/Finish
CompletionLocation
Sheet
Depth (ft)S
T
Exploration Number
20180398E002
8/22/18,8/22/18
Logged by:
Shelby Tube Sample
140# / 30"
Geologic Drill / Mini Track
Well Ground Surface Elevation (ft)
Grab SampleSymbol 5 inches
40
Datum
Hammer Weight/Drop
Sampler Type (ST):AESIBOR 20180398E002.GPJ November 18, 20202323
3232
4848
Particle Size Distribution Report
PERCENT FINER0
10
20
30
40
50
60
70
80
90
100
GRAIN SIZE - mm.
0.0010.010.1110100
% +3"Coarse
% Gravel
Fine Coarse Medium
% Sand
Fine Silt
% Fines
Clay
0.0 7.5 9.1 4.1 16.3 23.7 39.36 in.3 in.2 in.1½ in.1 in.¾ in.½ in.3/8 in.#4#10#20#30#40#60#100#140#200TEST RESULTS
Opening Percent Spec.*Pass?
Size Finer (Percent)(X=Fail)
Material Description
Atterberg Limits (ASTM D 4318)
Classification
Coefficients
Date Received:Date Tested:
Tested By:
Checked By:
Title:
Date Sampled:Location: Onsite
Sample Number: EB-1 Depth: 5'
Client:
Project:
Project No:Figure
Very Silty Gravelly SAND
1.5
1
.75
.375
#4
#8
#10
#20
#40
#60
#100
#200
#270
100.0
92.5
92.5
88.1
83.4
80.2
79.3
73.8
63.0
48.8
42.5
39.3
38.5
np nv
SM A-4(0)
12.7521 6.2954 0.3792
0.2641
8-24-18 8-24-18
BN
BG
8-22-18
Greene Gasaway
RSD Chelan Ave Properties
180398 E001
PL=LL=PI=
USCS (D 2487)=AASHTO (M 145)=
D90=D85=D60=
D50=D30=D15=
D10=Cu=Cc=
Remarks
*(no specification provided)
Particle Size Distribution Report
PERCENT FINER0
10
20
30
40
50
60
70
80
90
100
GRAIN SIZE - mm.
0.0010.010.1110100
% +3"Coarse
% Gravel
Fine Coarse Medium
% Sand
Fine Silt
% Fines
Clay
0.0 11.3 17.8 5.3 13.4 22.8 29.46 in.3 in.2 in.1½ in.1 in.¾ in.½ in.3/8 in.#4#10#20#30#40#60#100#140#200TEST RESULTS
Opening Percent Spec.*Pass?
Size Finer (Percent)(X=Fail)
Material Description
Atterberg Limits (ASTM D 4318)
Classification
Coefficients
Date Received:Date Tested:
Tested By:
Checked By:
Title:
Date Sampled:Location: Onsite
Sample Number: EB-7 Depth: 5'
Client:
Project:
Project No:Figure
Silty Gravelly SAND
1.5
1
.75
.375
#4
#8
#10
#20
#40
#60
#100
#200
#270
100.0
88.7
88.7
77.5
70.9
66.6
65.6
60.8
52.2
39.2
32.7
29.4
28.8
np nv
SM A-2-4(0)
27.6933 13.8219 0.7604
0.3864 0.0931
8-24-18 8-24-18
BN
BG
8-22-18
Greene Gasaway
RSD Chelan Ave Properties
180398 E001
PL=LL=PI=
USCS (D 2487)=AASHTO (M 145)=
D90=D85=D60=
D50=D30=D15=
D10=Cu=Cc=
Remarks
*(no specification provided)
16
19
20
13
17
17
18
25
33
S-1
S-2
S-3
Bottom of exploration boring at 14 feet
No groundwater encountered.
Grass / Topsoil
Vashon Lodgement Till
Slightly moist, oxidized gray, very silty, fine SAND, some gravel; unsorted
(SM).
Becomes moist to very moist, gray.
Becomes moist.
1 of 1
NAVD 88
DV2" OD Split Spoon Sampler (SPT)
3" OD Split Spoon Sampler (D & M)Water LevelProject Name
CJKWater Level ()Approved by:
30
Blows/Foot
Samples~434
5
10
15
20
EB-5
Ring Sample
No RecoveryGraphic 10 Other TestsHole Diameter (in)
DESCRIPTION
Driller/Equipment
Blows/6"Exploration Boring
Water Level at time of drilling (ATD)
Renton School District Elementary School No. 16
M - Moisture
Project Number
20
Renton, WA
Date Start/Finish
CompletionLocation
Sheet
Depth (ft)S
T
Exploration Number
20180398E002
8/22/18,8/22/18
Logged by:
Shelby Tube Sample
140# / 30"
Geologic Drill / Mini Track
Well Ground Surface Elevation (ft)
Grab SampleSymbol 5 inches
40
Datum
Hammer Weight/Drop
Sampler Type (ST):AESIBOR 20180398E002.GPJ November 18, 20203939
3434
58
7
10
12
23
50/4"
S-1
S-2
Bottom of exploration boring at 10.8 feet
No groundwater encountered.
Grass / Topsoil
Vashon Lodgement Till
Moist to very moist, gray with some oxidation, very silty, fine to medium
SAND, some gravel; unsorted (SM).
Contains trace to some coarse sand (SM).
1 of 1
NAVD 88
DV2" OD Split Spoon Sampler (SPT)
3" OD Split Spoon Sampler (D & M)Water LevelProject Name
CJKWater Level ()Approved by:
30
Blows/Foot
Samples~435
5
10
15
20
EB-6
Ring Sample
No RecoveryGraphic 10 Other TestsHole Diameter (in)
DESCRIPTION
Driller/Equipment
Blows/6"Exploration Boring
Water Level at time of drilling (ATD)
Renton School District Elementary School No. 16
M - Moisture
Project Number
20
Renton, WA
Date Start/Finish
CompletionLocation
Sheet
Depth (ft)S
T
Exploration Number
20180398E002
8/22/18,8/22/18
Logged by:
Shelby Tube Sample
140# / 30"
Geologic Drill / Mini Track
Well Ground Surface Elevation (ft)
Grab SampleSymbol 5 inches
40
Datum
Hammer Weight/Drop
Sampler Type (ST):AESIBOR 20180398E002.GPJ November 18, 20202222
5050/4"
19
34
32
10
19
31
S-1
S-2
Bottom of exploration boring at 11.5 feet
No groundwater encountered.
Grass / Topsoil
Vashon Lodgement Till
Moist, gray, silty, gravelly, fine to medium SAND; unsorted (SM).
As above.
1 of 1
NAVD 88
DV2" OD Split Spoon Sampler (SPT)
3" OD Split Spoon Sampler (D & M)Water LevelProject Name
CJKWater Level ()Approved by:
30
Blows/Foot
Samples~433
5
10
15
20
EB-7
Ring Sample
No RecoveryGraphic 10 Other TestsHole Diameter (in)
DESCRIPTION
Driller/Equipment
Blows/6"Exploration Boring
Water Level at time of drilling (ATD)
Renton School District Elementary School No. 16
M - Moisture
Project Number
20
Renton, WA
Date Start/Finish
CompletionLocation
Sheet
Depth (ft)S
T
Exploration Number
20180398E002
8/22/18,8/22/18
Logged by:
Shelby Tube Sample
140# / 30"
Geologic Drill / Mini Track
Well Ground Surface Elevation (ft)
Grab SampleSymbol 5 inches
40
Datum
Hammer Weight/Drop
Sampler Type (ST):AESIBOR 20180398E002.GPJ November 18, 202066
3364
50/4"
50/1"
S-1
S-2
Bottom of exploration boring at 10.1 feet
No groundwater encountered.
Grass / Topsoil
Vashon Lodgement Till
Moist, gray, very silty, fine to medium SAND, some gravel; unsorted (SM).
Poor recovery due to gravel.
1 of 1
NAVD 88
DV2" OD Split Spoon Sampler (SPT)
3" OD Split Spoon Sampler (D & M)Water LevelProject Name
CJKWater Level ()Approved by:
30
Blows/Foot
Samples~414
5
10
15
20
EB-8
Ring Sample
No RecoveryGraphic 10 Other TestsHole Diameter (in)
DESCRIPTION
Driller/Equipment
Blows/6"Exploration Boring
Water Level at time of drilling (ATD)
Renton School District Elementary School No. 16
M - Moisture
Project Number
20
Renton, WA
Date Start/Finish
CompletionLocation
Sheet
Depth (ft)S
T
Exploration Number
20180398E002
8/22/18,8/22/18
Logged by:
Shelby Tube Sample
140# / 30"
Geologic Drill / Mini Track
Well Ground Surface Elevation (ft)
Grab SampleSymbol 5 inches
40
Datum
Hammer Weight/Drop
Sampler Type (ST):AESIBOR 20180398E002.GPJ November 18, 20205050/4"
5050/1"
2
3
2
12
18
22
14
18
28
50/6"
S-1
S-2
S-3
S-4
Bottom of exploration boring at 10.5 feet
No groundwater encountered.
Sod / Topsoil - ~4 inches
Vashon Lodgement Till
Moist, orangish brown, silty, fine SAND, trace gravel; frequent organics
(charcoal/rootlets) (SM).
Moist, orangish gray to brownish gray, silty, fine SAND, trace gravel;
unsorted; diamict-like appearance; occasional organics (rootlets) (SM).
Moist, brownish gray, silty, fine SAND, trace gravel; rare organics; gravels
are subrounded, some broken; unsorted; diamict-like appearance (SM).
Driller notes hard drilling.
Moist, gray, silty, fine SAND, trace gravel; gravels are fine and subrounded;
unsorted; diamict-like appearance (SM).
1 of 1
NAVD 88
ALG2" OD Split Spoon Sampler (SPT)
3" OD Split Spoon Sampler (D & M)Water LevelProject Name
JHSWater Level ()Approved by:
30
Blows/Foot
Samples~436
5
10
15
20
EB-9
Ring Sample
No RecoveryGraphic 10 Other TestsHole Diameter (in)
DESCRIPTION
Driller/Equipment
Blows/6"Exploration Boring
Water Level at time of drilling (ATD)
Renton School District Elementary School No. 16
M - Moisture
Project Number
20
Renton, WA
Date Start/Finish
CompletionLocation
Sheet
Depth (ft)S
T
Exploration Number
20180398E002
9/27/19,9/27/19
Logged by:
Shelby Tube Sample
140# / 30"
Boretec / Rubber-Track Volvo EC55C HSA
Well Ground Surface Elevation (ft)
Grab SampleSymbol 8 inches
40
Datum
Hammer Weight/Drop
Sampler Type (ST):AESIBOR 20180398E002.GPJ November 18, 202055
4040
4646
5050/6"
4
5
6
2
3
10
40
50/6"
19
20
50/5"
50/5"
S-1
S-2
S-3
S-4
S-5
Bottom of exploration boring at 15.4 feet
No groundwater encountered.
Sod / Topsoil - 4 inches
Fill / Duff
Moist, orangish gray, silty, fine SAND, trace gravel; occasional organics
(charcoal/rootlets); unsorted (SM).
Vashon Recessional Outwash
Slightly moist, brownish gray, fine SAND, some silt, trace gravel;
occasional organics (charcoal/roots) (SP-SM).
Vashon Lodgement Till
Slightly moist, brownish gray, fine SAND, some silt, trace gravel; rare
organics (rootlets); unsorted (SP-SM).
Hard drilling/rig chatter at 9 feet.
Moist, brownish gray, fine to medium SAND, some silt to silty, trace gravel;
weakly stratified zones of silty sand, unsorted, diamict-like and medium
sand, some silt (SM/SP-SM).
Hard drilling/rig chatter at 12 feet.
Moist to very moist, fine to medium SAND, some silt to silty, trace gravel;
gravels are subrounded; faintly gradationally stratified (SP-SM/SM).
1 of 1
NAVD 88
ALG2" OD Split Spoon Sampler (SPT)
3" OD Split Spoon Sampler (D & M)Water LevelProject Name
JHSWater Level ()Approved by:
30
Blows/Foot
Samples~431
5
10
15
20
EB-10
Ring Sample
No RecoveryGraphic 10 Other TestsHole Diameter (in)
DESCRIPTION
Driller/Equipment
Blows/6"Exploration Boring
Water Level at time of drilling (ATD)
Renton School District Elementary School No. 16
M - Moisture
Project Number
20
Renton, WA
Date Start/Finish
CompletionLocation
Sheet
Depth (ft)S
T
Exploration Number
20180398E002
9/27/19,9/27/19
Logged by:
Shelby Tube Sample
140# / 30"
Boretec / Rubber-Track Volvo EC55C HSA
Well Ground Surface Elevation (ft)
Grab SampleSymbol 8 inches
40
Datum
Hammer Weight/Drop
Sampler Type (ST):AESIBOR 20180398E002.GPJ November 18, 20201111
1313
90
5050/5"
5050/5"
2
2
1
5
8
10
9
9
10
28
50/6"
40
50/5"
S-1
S-2
S-3
S-4
S-5
Bottom of exploration boring at 15.9 feet
No groundwater encountered.
Sod / Topsoil - 4 inches
Forest Duff
Moist, orangish brown, silty, fine SAND, trace gravel; frequent organics
(charcoal/rootlets) (SM).
Vashon Recessional Outwash
Moist, brownish gray with bands of iron oxide staining, fine to medium
SAND, some silt, trace gravel; rare organics (roots); gradationally stratified
(SP-SM).
As above; gradationally stratified (SP-SM).
Vashon Lodgement Till
Hard drilling/rig chatter at 7 feet.
Moist, gray, silty, fine SAND, some gravel, some medium to coarse sand;
unsorted; diamict-like appearance (SM).
Hard drilling/rig chatter at 13 feet.
As above; gravels are fine to coarse, broken, and weathered; unsorted;
diamict-like appearance (SM).
1 of 1
NAVD 88
ALG2" OD Split Spoon Sampler (SPT)
3" OD Split Spoon Sampler (D & M)Water LevelProject Name
JHSWater Level ()Approved by:
30
Blows/Foot
Samples~409
5
10
15
20
EB-11
Ring Sample
No RecoveryGraphic 10 Other TestsHole Diameter (in)
DESCRIPTION
Driller/Equipment
Blows/6"Exploration Boring
Water Level at time of drilling (ATD)
Renton School District Elementary School No. 16
M - Moisture
Project Number
20
Renton, WA
Date Start/Finish
CompletionLocation
Sheet
Depth (ft)S
T
Exploration Number
20180398E002
9/27/19,9/27/19
Logged by:
Shelby Tube Sample
140# / 30"
Boretec / Rubber-Track Volvo EC55C HSA
Well Ground Surface Elevation (ft)
Grab SampleSymbol 8 inches
40
Datum
Hammer Weight/Drop
Sampler Type (ST):AESIBOR 20180398E002.GPJ November 18, 202033
1818
1919
78
5050/5"
3
4
5
13
29
40
22
29
48
40
50/4"
50/3"
S-1
S-2
S-3
S-4
S-5
Bottom of exploration boring at 15.3 feet
No groundwater encountered.
Fill
Moist, light brown to dark brown, silty, fine SAND, some gravel; abundant
organics (rootlets/wood debris); poor recovery (SM).
Vashon Lodgement Till
Slightly moist to moist, brownish gray with mottled iron oxide staining, silty,
fine SAND, some gravel; gravels are fine to coarse, weathered, and
broken; unsorted; diamict-like appearance (SM).
As above; less iron oxide mottling; some coarse sand; broken gravels
throughout (SM).
Hard drilling/rig chatter at 7 feet.
Slightly moist, brownish gray, silty, fine SAND, some gravel; section (~2
inches thick) of broken gravel (SM).
Hard drilling at 11.5 feet.
Rig chatter at 12.5 feet.
Moist, brownish gray, silty, fine SAND, some gravel; broken gravel
throughout; unsorted; diamict like (SM).
1 of 1
NAVD 88
ALG2" OD Split Spoon Sampler (SPT)
3" OD Split Spoon Sampler (D & M)Water LevelProject Name
JHSWater Level ()Approved by:
30
Blows/Foot
Samples~425
5
10
15
20
EB-12
Ring Sample
No RecoveryGraphic 10 Other TestsHole Diameter (in)
DESCRIPTION
Driller/Equipment
Blows/6"Exploration Boring
Water Level at time of drilling (ATD)
Renton School District Elementary School No. 16
M - Moisture
Project Number
20
Renton, WA
Date Start/Finish
CompletionLocation
Sheet
Depth (ft)S
T
Exploration Number
20180398E002
9/27/19,9/27/19
Logged by:
Shelby Tube Sample
140# / 30"
Boretec / Rubber-Track Volvo EC55C HSA
Well Ground Surface Elevation (ft)
Grab SampleSymbol 8 inches
40
Datum
Hammer Weight/Drop
Sampler Type (ST):AESIBOR 20180398E002.GPJ November 18, 202099
69
77
5050/4"
5050/3"
3
2
1
2
9
15
8
11
16
10
15
16
50/6"
40
50/5"
S-1
S-2
S-3
S-4
S-5
S-6
Bottom of exploration boring at 20.9 feet
No groundwater encountered.
Fill
Moist, orangish brown to dark brown, silty, fine to medium SAND, some
gravel; frequent organics (charcoal/rootlets) (SM).
Upper 6 inches: very moist, brown to grayish brown, silty, fine to medium
SAND, some gravel (SM).
Vashon Lodgement Till
Lower 6 inches: moist, brownish gray with bands of iron oxide staining,
silty, fine SAND, trace to some gravel; unsorted; diamict-like (SM),
Upper 6 inches: as above (SM).
Lower 6 inches: becomes moist, gray to greenish gray, silty, fine SAND,
some gravel; gravels are fine to coarse, weathered, and broken (SM).
Upper 4 inches: as above; moderate to strong organic/petrochemical odor
(SM).
Moist, brownish gray with mottled iron oxide staining, silty, medium SAND,
some gravel, some purple gravel (rhyolite?); unsorted; diamict-like (SM).
Hard drilling/rig chatter at 12.5 feet.
Moist, brownish gray, silty, fine to medium SAND, some gravel; unsorted;
diamict-like appearance; gravels are subrounded, some broken, and
weathered (SM).
Upper 6 in: moist, brownish gray, interbedded silty, fine SAND (SM) and
medium SAND, trace silt (SP).
At 20.5 ft: Vashon Lodgement Till / Vashon Advance Outwash ? - Lower
6 in: moist to very moist, brownish gray, fine to medium SAND, some silt,
trace gravel (SP-SM); moderately bedded with occasional interbeds (~1/2
inch thick) of silty fine sand (SM).
1 of 1
NAVD 88
ALG2" OD Split Spoon Sampler (SPT)
3" OD Split Spoon Sampler (D & M)Water LevelProject Name
JHSWater Level ()Approved by:
30
Blows/Foot
Samples~424
5
10
15
20
EB-13
Ring Sample
No RecoveryGraphic 10 Other TestsHole Diameter (in)
DESCRIPTION
Driller/Equipment
Blows/6"Exploration Boring
Water Level at time of drilling (ATD)
Renton School District Elementary School No. 16
M - Moisture
Project Number
20
Renton, WA
Date Start/Finish
CompletionLocation
Sheet
Depth (ft)S
T
Exploration Number
20180398E002
9/27/19,9/27/19
Logged by:
Shelby Tube Sample
140# / 30"
Boretec / Rubber-Track Volvo EC55C HSA
Well Ground Surface Elevation (ft)
Grab SampleSymbol 8 inches
40
Datum
Hammer Weight/Drop
Sampler Type (ST):AESIBOR 20180398E002.GPJ November 18, 202033
2424
2727
3131
5050/6"
5050/5"
3
2
2
10
20
22
9
15
23
40
50/4"
50/6"
17
13
40
S-1
S-2
S-3
S-4
S-5
S-6
Bottom of exploration boring at 21.5 feet
No groundwater encountered.
Sod / Topsoil - 4 inches
Fill
Moist, orangish brown, silty, fine SAND, trace gravel; frequent organics
(charcoal/rootlets) (SM).
Vashon Lodgement Till
Slightly moist, brownish gray with mottled iron oxide staining, silty, fine
SAND, some gravel; massive; unsorted; gravels are fine to coarse, broken,
and weathered (SM).
Hard drilling at 4 feet.
Moist, brownish gray with mottled iron oxide staining, silty, fine SAND,
some gravel; unsorted; diamict-like; gravels are broken and weathered
(SM).
Slightly moist to moist, brownish gray, silty, fine to medium SAND, some
gravel; gravels are broken and weathered; section (~2 inches thick) of
broken gravel; less silt and moisture with depth (SM).
Hard drilling/rig chatter at 11 feet.
Moist, brownish gray, silty, fine to medium SAND, trace to some gravel;
gravels are broken throughout; unsorted; diamict-like appearance (SM).
Hard drilling/rig chatter at 16 feet.
Upper 5 inches: moist, brownish gray, silty, fine SAND, trace gravel;
unsorted; diamict-like (SM).
At 20.4 ft: Vashon Advance Outwash / Vashon Lodgement Till ? -
Becomes moist to very moist, brownish gray, interbedded, silty, fine SAND
(SM) and fine to medium SAND, some silt (SP-SM); moderately
bedded in layers (~1/2 inch thick); higher moisture in less silty interbeds.
1 of 1
NAVD 88
ALG2" OD Split Spoon Sampler (SPT)
3" OD Split Spoon Sampler (D & M)Water LevelProject Name
JHSWater Level ()Approved by:
30
Blows/Foot
Samples~421
5
10
15
20
EB-14
Ring Sample
No RecoveryGraphic 10 Other TestsHole Diameter (in)
DESCRIPTION
Driller/Equipment
Blows/6"Exploration Boring
Water Level at time of drilling (ATD)
Renton School District Elementary School No. 16
M - Moisture
Project Number
20
Renton, WA
Date Start/Finish
CompletionLocation
Sheet
Depth (ft)S
T
Exploration Number
20180398E002
9/27/19,9/27/19
Logged by:
Shelby Tube Sample
140# / 30"
Boretec / Rubber-Track Volvo EC55C HSA
Well Ground Surface Elevation (ft)
Grab SampleSymbol 8 inches
40
Datum
Hammer Weight/Drop
Sampler Type (ST):AESIBOR 20180398E002.GPJ November 18, 202044
4242
3838
5050/4"
5050/6"
53
3
4
4
4
15
13
5
6
8
3
41
50/3"
27
47
50/5"
15
17
32
S-1
S-2
S-3
S-4
S-5
S-6
Bottom of exploration boring at 16.5 feet
No groundwater encountered.
Topsoil - 6 inches
Moist, dark brown, sandy, SILT; frequent rootlets/organics (ML).
Fill
Lower 6 inches: moist, orangish brown with moderate oxidation, mostly fine
to medium SAND, some silt; occasional mica, charcoal, and rootlets;
discontinuous lens of dark brown, sandy, silt (SP-ML).
Upper 6 inches: as above; becomes heavily oxidized; silty; moderate fine
organics/rootlets (SM).
Lower 12 inches: moist, grayish brown with slight to moderate oxidation
staining, silty, fine SAND, some gravel; one broken gravel in sampler;
unsorted (SM).
Moist to very moist, brownish gray, silty, fine SAND, some gravel; scattered
clasts of brown, sandy, silt with moderate oxidation; unsorted (SM-ML).
Vashon Lodgement Till
Increased drilling difficulty at 6.5 feet.
Moist, brownish gray with slight oxidation, silty, fine to medium SAND,
some gravel; becomes very moist within sandier zones; unsorted (SM).
As above; moist.
As above.
1 of 1
NAVD 88
CRC2" OD Split Spoon Sampler (SPT)
3" OD Split Spoon Sampler (D & M)Water LevelProject Name
JHSWater Level ()Approved by:
30
Blows/Foot
Samples~433
5
10
15
20
EB-15
Ring Sample
No RecoveryGraphic 10 Other TestsHole Diameter (in)
DESCRIPTION
Driller/Equipment
Blows/6"Exploration Boring
Water Level at time of drilling (ATD)
Renton School District Elementary School No. 16
M - Moisture
Project Number
20
Renton, WA
Date Start/Finish
CompletionLocation
Sheet
Depth (ft)S
T
Exploration Number
20180398E002
10/6/20,10/6/20
Logged by:
Shelby Tube Sample
140# / 30"
Advance Drill Tech / D50 Mobile Track Rig
Well Ground Surface Elevation (ft)
Grab SampleSymbol 8 inches
40
Datum
Hammer Weight/Drop
Sampler Type (ST):AESIBOR 20180398E002.GPJ November 18, 202088
2828
1414
5050/3"
5050/5"
4949
4
5
14
5
10
18
15
41
35
41
50/5"
50/6"
S-1
S-2
S-3
S-4
S-5
Bottom of exploration boring at 10.5 feet
No groundwater encountered.
Topsoil - 12 inches
Moist to very moist, dark brown,sandy, SILT; frequent fine organic debris,
roots, and rootlets (ML).
Vashon Lodgement Till
Lower 12 inches: moist, brown with moderate oxidation, silty, fine SAND,
trace gravel; occasional rootlets (SM).
Grinding and increased drilling difficulty at 2 feet.
Moist, grayish brown with slight oxidation, silty, fine to medium SAND,
some gravel to gravelly; contains sandier zones; unsorted (SM).
As above; becomes brownish gray; lack of sandier zones; blowcounts are
slightly overstated (SM).
Bouncing on rock at 5 feet.
Moist, brownish gray, silty, fine to medium SAND, some gravel; unsorted
(SM).
As above.
1 of 1
NAVD 88
CRC2" OD Split Spoon Sampler (SPT)
3" OD Split Spoon Sampler (D & M)Water LevelProject Name
JHSWater Level ()Approved by:
30
Blows/Foot
Samples~428
5
10
15
20
EB-16
Ring Sample
No RecoveryGraphic 10 Other TestsHole Diameter (in)
DESCRIPTION
Driller/Equipment
Blows/6"Exploration Boring
Water Level at time of drilling (ATD)
Renton School District Elementary School No. 16
M - Moisture
Project Number
20
Renton, WA
Date Start/Finish
CompletionLocation
Sheet
Depth (ft)S
T
Exploration Number
20180398E002
10/6/20,10/6/20
Logged by:
Shelby Tube Sample
140# / 30"
Advance Drill Tech / D50 Mobile Track Rig
Well Ground Surface Elevation (ft)
Grab SampleSymbol 8 inches
40
Datum
Hammer Weight/Drop
Sampler Type (ST):AESIBOR 20180398E002.GPJ November 18, 20201919
2828
76
5050/5"
5050/6"
3
4
5
10
18
17
11
38
48
22
32
34
50/3"
50
36
36
S-1
S-2
S-3
S-4
S-5
S-6
Bottom of exploration boring at 16.5 feet
No groundwater encountered.
Topsoil - 6 inches
Vashon Lodgement Till
Lower 6 inches: moist, brown with moderate to heavy oxidation, silty, fine
to medium SAND, trace gravel; moderate rootlets/charcoal (SM).
Drilling difficulty and grinding increases at 1.5 feet.
Moist, grayish brown with slight to moderate oxidation, silty, fine to medium
SAND, trace gravel; unsorted (SM).
Drilling difficulty increases.
Moist, brownish gray with slight oxidation, silty, fine to medium SAND,
some gravel; unsorted; broken gravel within sampler; blowcounts are
slightly overstated (SM).
As above.
As above; poor recovery; bouncing on rock; blowcounts overstated.
As above; broken gravel within sampler; blowcounts slightly overstated.
1 of 1
NAVD 88
CRC2" OD Split Spoon Sampler (SPT)
3" OD Split Spoon Sampler (D & M)Water LevelProject Name
JHSWater Level ()Approved by:
30
Blows/Foot
Samples~428
5
10
15
20
EB-17
Ring Sample
No RecoveryGraphic 10 Other TestsHole Diameter (in)
DESCRIPTION
Driller/Equipment
Blows/6"Exploration Boring
Water Level at time of drilling (ATD)
Renton School District Elementary School No. 16
M - Moisture
Project Number
20
Renton, WA
Date Start/Finish
CompletionLocation
Sheet
Depth (ft)S
T
Exploration Number
20180398E002
10/6/20,10/6/20
Logged by:
Shelby Tube Sample
140# / 30"
Advance Drill Tech / D50 Mobile Track Rig
Well Ground Surface Elevation (ft)
Grab SampleSymbol 8 inches
40
Datum
Hammer Weight/Drop
Sampler Type (ST):AESIBOR 20180398E002.GPJ November 18, 202099
2525
86
66
5050/3"
72
3
4
5
11
13
36
19
21
31
12
44
50/5"
43
50/5"
15
50/5"
S-1
S-2
S-3
S-4
S-5
S-6
Bottom of exploration boring at 16 feet
No groundwater encountered.
Topsoil - 6 inches
Fill
Lower 6 inches: moist, brown with slight oxidation, silty, fine SAND;
occasional rootlets/charcoal (SM).
Upper 6 inches: as above (SM).
Vashon Lodgement Till
Lower 12 inches: moist, grayish brown, silty, fine to medium SAND, trace
gravel; occasional rootlets; unsorted (SM).
Drilling difficulty increases at 4.5 feet.
Moist, brownish gray with slight oxidation, silty, fine to medium SAND,
some gravel; broken gravel within sampler; unsorted (SM).
As above; lack of slight oxidation (SM).
As above; pounding on rock; blowcounts overstated.
As above; contains sandier zones; ranges to very moist within sandier
zones.
1 of 1
NAVD 88
CRC2" OD Split Spoon Sampler (SPT)
3" OD Split Spoon Sampler (D & M)Water LevelProject Name
JHSWater Level ()Approved by:
30
Blows/Foot
Samples~431
5
10
15
20
EB-18
Ring Sample
No RecoveryGraphic 10 Other TestsHole Diameter (in)
DESCRIPTION
Driller/Equipment
Blows/6"Exploration Boring
Water Level at time of drilling (ATD)
Renton School District Elementary School No. 16
M - Moisture
Project Number
20
Renton, WA
Date Start/Finish
CompletionLocation
Sheet
Depth (ft)S
T
Exploration Number
20180398E002
10/6/20,10/6/20
Logged by:
Shelby Tube Sample
140# / 30"
Advance Drill Tech / D50 Mobile Track Rig
Well Ground Surface Elevation (ft)
Grab SampleSymbol 8 inches
40
Datum
Hammer Weight/Drop
Sampler Type (ST):AESIBOR 20180398E002.GPJ November 18, 202099
4949
52
5050/5"
5050/5"
5050/5"
3
5
8
4
4
10
3
18
50/6"
17
28
50/6"
36
50/6"
S-1
S-2
S-3
S-4
S-5
Bottom of exploration boring at 11 feet
No groundwater encountered.
Topsoil - 2 inches
Fill
Lower 10 inches: moist, brown, silty, fine to medium SAND, some gravel;
moderate rootlets/fine organic debris/charcoal; chaotic structure (SM).
As above; poor recovery/brick debris (SM).
Upper 6 inches: as above.
Vashon Lodgement Till
Lower 12 inches: moist, grayish light brown with slight oxidation, silty, fine
to medium SAND, some gravel; broken gravel within sampler; unsorted
(SM).
Moist, brownish gray, silty, fine to medium SAND, some gravel; broken
gravel within sampler; unsorted (SM).
As above.
1 of 1
NAVD 88
CRC2" OD Split Spoon Sampler (SPT)
3" OD Split Spoon Sampler (D & M)Water LevelProject Name
JHSWater Level ()Approved by:
30
Blows/Foot
Samples~430
5
10
15
20
EB-19
Ring Sample
No RecoveryGraphic 10 Other TestsHole Diameter (in)
DESCRIPTION
Driller/Equipment
Blows/6"Exploration Boring
Water Level at time of drilling (ATD)
Renton School District Elementary School No. 16
M - Moisture
Project Number
20
Renton, WA
Date Start/Finish
CompletionLocation
Sheet
Depth (ft)S
T
Exploration Number
20180398E002
10/6/20,10/6/20
Logged by:
Shelby Tube Sample
140# / 30"
Advance Drill Tech / D50 Mobile Track Rig
Well Ground Surface Elevation (ft)
Grab SampleSymbol 8 inches
40
Datum
Hammer Weight/Drop
Sampler Type (ST):AESIBOR 20180398E002.GPJ November 18, 20201313
1414
5050/6"
5050/6"
5050/6"
2
2
2
5
11
9
8
11
18
48
41
50/6"
50/3"
S-1
S-2
S-3
S-4
S-5
Bottom of exploration boring at 10.5 feet
No groundwater encountered.
Topsoil - 2 inches
Fill
Lower 10 inches: moist, brown to dark brown with moderate oxidation, silty,
fine to medium SAND; moderate roots, rootlets, and charcoal; chaotic
structure (SM).
Vashon Lodgement Till
Moist, grayish brown with moderate oxidation staining, silty, fine SAND;
unsorted (SM).
Increased drilling difficulty.
Moist, grayish brown with slight oxidation, silty, fine to medium SAND,
some gravel; unsorted (SM).
Moist, brownish gray, silty, fine to medium SAND, some gravel; unsorted
(SM).
No recovery; bouncing on rock.
1 of 1
NAVD 88
CRC2" OD Split Spoon Sampler (SPT)
3" OD Split Spoon Sampler (D & M)Water LevelProject Name
JHSWater Level ()Approved by:
30
Blows/Foot
Samples~434
5
10
15
20
EB-20
Ring Sample
No RecoveryGraphic 10 Other TestsHole Diameter (in)
DESCRIPTION
Driller/Equipment
Blows/6"Exploration Boring
Water Level at time of drilling (ATD)
Renton School District Elementary School No. 16
M - Moisture
Project Number
20
Renton, WA
Date Start/Finish
CompletionLocation
Sheet
Depth (ft)S
T
Exploration Number
20180398E002
10/6/20,10/6/20
Logged by:
Shelby Tube Sample
140# / 30"
Advance Drill Tech / D50 Mobile Track Rig
Well Ground Surface Elevation (ft)
Grab SampleSymbol 8 inches
40
Datum
Hammer Weight/Drop
Sampler Type (ST):AESIBOR 20180398E002.GPJ November 18, 202044
2020
2929
5050/6"
5050/3"