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BUILDING DIVISION
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Earth & Environmental
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SUBSURFACE EXPLORATION
AND GEOTECHNICAL ENGINEERING EVALUATION
PROPOSED RENTON RETAIL STORE
SW 7th STREET AND HARDIE AVENUE SW
RENTON, WASHINGTON
Prepared For
Washington Land Design
10700 Meridian Avenue North
Seattle, Washington 98133
Prepared by,
AGRA Earth and Environmental, Inc.
11335 NE 122nd Way, Suite 100
Kirkland, Washington 98034
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October 1995
11-10521-00
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* AGRA
Earth & Environmental
A V R A AGRA Earth&
Environmental, Inc.
Earth & Environmental 11335 NE 122nd Way
sulto 100
Kirkland, Washington
U.S.A. 98034-6918
17 October 1995 - Tel (206) 820-4669
1 1-1 05 21-00 Fax (206) 821-3914
Washington Land Design
10700 Meridian Avenue North, Suite 503
Seattle, Washington 98133
Attention: Mr. Jim Towslee
Subject: Subsurface Exploration and Geotechnical Engineering Evaluation
Proposed Renton Retail Store
SW 7th Street and Hardie Avenue SW
Renton, Washington
Dear Mr. Towslee:
This report presents the results of our geotechnical engineering evaluation for the above
referenced project. The scope of services for this project consisted of field exploration,
geotechnical engineering analyses, laboratory testing, and preparation of this report. The
scope of work for this report was performed in accordance with our Proposal for Geotechnical
and Phase I Environmental Studies dated 12 September 1995. Written authorization to
proceed with this project was provided by Washington Land Design in your letter dated 15
September 1995.
This report has been prepared in accordance with generally accepted geotechnical engineering
practices for the exclusive use of Washington Land Design and their agents for specific
application to this project. In the event of any changes in the nature of the project which may
affect conclusions and recommendations presented in this report, we should be allowed to
review and modify them, as necessary, to reflect those changes.
We appreciate this opportunity to be of service to you, and are available to answer any
questions you have regarding this report or other geotechnical aspects of the project.
Respectfully submitted,
AGRA Earth and Environmental, Inc.
Thomas A. Jones
Senior Project Engineer
Engineering R Environmental Services
TABLE OF CONTENTS
1 1-10 521-00
1.0 SUMMARY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
2.0 PROJECT DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3.0 SITE CONDITIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
I 3.1 Site Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3.2 Surface Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I . . . . . . . . 4
3.3 Subsurface Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
j 3.4 Groundwater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
4.0 CONCLUSIONS AND RECOMMENDATIONS . . . . . . . . . . . . . . . . . . . . . . . . . 5
4.1 Liquefaction Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
4.2 Site Preparation . . . . . . . . . . . . ... . . . . . . . . . . . . . . . . . . . . . . . . . . 6
4.3 Structural Fill . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
4.4 Utility Trenching and Backfilling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
4.5 Foundations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
4.5.1 Shallow Foundations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
4.5.2 Pile Foundations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
4.6 Slab-On-Grade Floors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
4.7 Backfilled Walls and Retaining Structures . . . . . . . . . . . . . . . . . . . . . . 13
4.8 Drainage Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
4.9 Temporary and Permanent Slopes . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
4.10 Seismic Criteria . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
5.0 PAVEMENT DESIGN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
6.0 CLOSURE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Figure 1 - Site and Exploration Plan
Appendix A - Field Exploration Procedures and Logs
Appendix B - Laboratory Test Procedures end Results
Appendix C - AASHTO Pavement Design
Appendix D - Geotechnical Investigation Fact Sheet and Foundation Design Criteria
I
SUBSURFACE EXPLORATION AND GEOTECHNICAL 1 1-1 0 521-00
ENGINEERING EVALUATION
.PROPOSED RENTON RETAIL STORE
SW 7TH STREET AND HARDIE AVENUE SW
RENTON, WASHINGTON
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I 1.0 SUMMARY
The proposed project is considered feasible from a geotechnical standpoint with respect to the
subsurface conditions encountered at the site. A brief summary of project geotechnical
considerations is presented below:
0 The subsurface exploration program for this project consisted of advancing 19
hollow-stem auger soil borings across the site. Subsurface soil conditions
encountered in the borings were somewhat variable, but generally consisted of
interlayered loose to medium dense sand and gravel, with varying silt content,
and some layers of silty sand and silt. Looser surficial soils were generally
underlain by medium dense to very dense sand and gravel deposits below about
20 feet depth. Much of the site was covered with about 2 inches of asphalt
paving, with varying thicknesses of paving base course and granular fill material
immediately beneath the pavement section. A significant portion of the site
was covered with an existing concrete masonry building, located mostly in
planned parking areas east of the proposed retail building, but covering a
narrow strip of the proposed building along its eastern side. No explorations
were completed within the footprint of the existing building.
• Groundwater was encountered in several of our explorations at depths ranging
from 7'/2 to 14 feet, and was measured in one groundwater monitoring well on
the site at a depth of 9.2 feet. Borings which did not encounter groundwater
were shallow and were terminated at or slightly above the groundwater table
0 Due to the very loose to loose density and grain-size distribution of the near-
surface soils, there is a high likelihood of liquefaction within these soils during
an earthquake of moderate size and duration which is typically used in design
in the Puget Sound area.
• The soils within the proposed building pad vary substantially and include soft
compressible silts and liquefaction susceptible soils. Therefore, we recommend
that the proposed building foundations be supported on drilled, augercast piles.
Slab on grade floors could be supported on a mat of compacted structural fill.
Geotechnical design parameters are presented in the text of this report.
• Relatively shallow groundwater levels were encountered across the site, even
though the explorations were completed during the late summer when seasonal
groundwater levels are likely near seasonal lows. It is therefore likely that
excavations on the site, such as for the installation of sewers and other buried
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Washington Land Design 1 1-1 0 521-00
17 October 1995 Page 2
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utilities, and for other areas such as vehicle maintenance pits, will encounter
groundwater seepage. Excavation dewatering will most likely be required to
facilitate such installations and permanent drainage and/or water-proofing
measures will be necessary for a vehicle maintenance pit.
• Due to the condition of the soils encountered within the proposed building pad,
we recommend that a mat of structural fill be constructed beneath all slab on
grade floors in order to provide more uniform support. The mat of structural fill
should be a minimum of 18 inches in thickness and consist of pit-run sand and
gravel or crushed recycled concrete which can be compacted to a minimum of
92 percent of the modified Proctor maximum dry density. Above the mat, we
recommend placing an additional 2 feet of surcharge fill which is nearly
equivalent to the design floor loads in order to preconsolidate the settlement
sensitive soils encountered in some of our borings. The mat and surcharge soils
should be completed at least 30 days prior to construction of the floor slabs.
Above the structural mat, a 6-inch thick layer of capillary break material should
be placed. A vapor barrier is not required.
• Much of the planned paved parking and driveway areas are covered by existing
asphalt paving which is approximately 2 inches thick and underlain by about 0
to 18 inches of crushed rock pavement base course and\or granular fill. The
existing pavement is in relatively poor condition. An overlay is suitable at the
site, provided remedial measures are used to remove excessively damaged
asphalt, replace inadequate subgrade soils, and possibly use an overlay
geotextile between the new and old pavement sections. We recommend
standard and heavy section overlays of 2 and 3 inches, respectively.
• Many of our borings encountered near-surface silty soils which are considered
to be moisture sensitive. Earthwork performed during or immediately after
extended periods of wet weather will be difficult or impossible if the soils are
over optimum in moisture content. On-site soils would not be compactible if
the moisture content is more than about 2 to 3 percent over optimum.
Imported structural fill or soil admixtures such as dry cement or lime may be
necessary for earthwork to proceed during these periods.
This summary is presented for introductory purposes only, and should be used in conjunction
with the full text of this report. The project description, site conditions, and our specific
geotechnical design recommendations are presented in the following report sections. The field
exploration procedures and logs are included with this report as Appendix A. Laboratory
testing procedures and results are included in Appendix B, while AASHTO pavement design
Washington Land Design 11.10521-00
17 October 1995 Page 3
calculations are presented in Appendix C. The Geotechnical Investigation Fact Sheet and
Design Criteria are presented in Appendix D.
2.0 PROJECT DESCRIPTION
We understand that the proposed project would consist of removing the existing retail building
on the site, and constructing a new retail store which includes the main building along with
associated parking areas, access driveways, utilities and landscaping. Possible future retail
space is identified north of the proposed building. The currently proposed site layout is
presented in our Site and Exploration Plan, Figure 1, included with this report. The planned
configuration would include a 133,000 square foot building with a vehicle maintenance center
and garden center on the north side. A finished floor elevation for the planned building has
not yet been determined, however we anticipate that the new building will closely match
existing grades.
The purpose of this evaluation was to establish general subsurface conditions at this site from
which conclusions and recommendations for foundation design, pavement design, and general
earthwork construction recommendations for the project could be formulated. The scope of
work consisted of a field exploration program, laboratory testing, geotechnical engineering
analyses, and preparation of this report. In the event that there are any changes in the nature,
design, elevation,or location of the proposed structure,the conclusions and recommendations
contained in this report should be reviewed by AGRA Earth and Environmental, Inc. (AEE) and
modified, as necessary,to reflect those changes. This report has been prepared in accordance
with generally accepted geotechnical engineering practice for the exclusive use of Washington
Land Design and their agents for specific application to this project.
3.0 SITE CONDITIONS
Site conditions for this study were evaluated between 21 and 25 September 1995. The
surface and subsurface conditions are described below, while the exploration procedures and
interpretive logs of the explorations are presented in Appendix A. The laboratory procedures
and results are presented in Appendix B and on the exploration logs, where appropriate. The
location of the proposed building and parking areas, as well as the approximate locations of
the explorations, are shown on the Site and Exploration Plan, Figure 1.
3.1 Site Description
The proposed project site is located at the southwest quadrant of the intersection of SW 7th
Street and Hardie Avenue SW in Renton, Washington. The site is currently developed and
consists of a partially vacated retail building surrounded by asphalt paving with several smaller
structures surrounding the main building. An unpaved area covered with brush and trees was
present to the west of the existing building, in the area of the proposed new retail building.
Estimated vertical relief across the site was on the order of 7 feet or less, with less than about
4 feet in the planned building area. The site is bordered on all sides by public roads or
developed commercial building property.
Washington Land Design 11-10521-00
17 October 1995 Page 4
3.2 Surface Conditions
Site topography was relatively flat, with previously engineered contours in most paved areas
to facilitate surface water drainage. The undeveloped area west of the existing building was
also relatively flat with the exception of a linear fill embankment that runs north-south along
the east side of this area. This fill embankment reportedly is the remaining portion of an old
railroad bed, and is generally about 3 feet higher than surrounding grades.
The majority of the site was covered by asphalt pavement and a retail building. The pavment
was about 2 inches thick, and in relatively poor condition, with widespread alligator cracking
and potholes in some areas. We observed existing groundwater monitoring well monuments
in the parking area near the southeast part of the site, and these appeared to be related to an
active remediation system on the neighboring service station site near Rainier Avenue South.
The wells were locked and we were unable to measure the groundwater levels within.
The undeveloped area west of the existing building, in the area of the proposed new building,
is generally characterized by dense blackberry undergrowth and numerous trees up to about
30 inches in butt diameter.
Surface water was not observed on the site at any time during our exploration program,
though our work was completed during seasonal dry weather.
3.3 Subsurface Conditions
Our exploration program consisted of drilling 19 hollow-stem auger soil borings in the building
and paving areas. In our opinion, the number of explorations was sufficient to address the
Geotechnical Investigation Requirements provided to us. The borings were advanced with a
truck-mounted drill by a local drilling company under subcontract to our firm. The
approximate locations of the explorations are presented on Figure 1, Site and Exploration Plan,
included at the end of this report. Detailed, interpretive logs of each exploration are included
in Appendix A.
The near surface soil conditions generally consisted of very loose to medium dense sand and
gravel with varying silt content, and with occasional layers of soft silt. In borings B-1 and 13-
10, relatively thick layers of soft silt were encountered between depths of 1 to 10 feet and
7 to 12 feet, respectively. These surficial conditions typically graded to medium dense to very
dense sand and sandy gravel at depths below about 15 to 20 feet. Some sandy soils
encountered in the borings had low density, uniform grain-size distribution, and were
saturated, which makes them prone to loss of shear strength due to liquefaction during a
design seismic event. Potentially liquefiable soils were encountered in all of the borings
completed within the proposed building pad at depths between 7 and 22 feet beneath the
existing ground surface. Liquefaction is discussed in a subsequent section of this report.
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Asphalt pavement covered a significant portion of the site, and generally consisted of 2 inches
f of pavement above 0 to 1 h feet of crushed aggregate base and/or granular fill material.
Undeveloped portions of the site were covered with organics and topsoil generally about 6 to
10 inches thick. Deeper topsoil should be expected around and beneath tree root balls and
in areas of particularly dense vegetation.
3.4 Groundwater
Groundwater was encountered in several of our borings at depths ranging from about 7.5 to
14 feet, and was measured in one groundwater well on the site at a depth of 9.2 feet.
Changes in groundwater conditions should be anticipated in response to fluctuations in
seasonal precipitation, on and off site land usage, and other factors. When interpreting
groundwater observations noted in this report and on exploration logs, one should note that
all of our explorations and groundwater observations were completed late in the summer at
the end of a long period of seasonal dry weather, and presumably when groundwater levels
were at or near seasonal lows. Based on our experience on a long-term project a few blocks
away, it appears that the seasonal high groundwater levels are about 1 '% feet above the
seasonal low levels. Therefore, it appears that seasonal high groundwater levels should be
anticipated to be about 6 feet beneath existing ground elevations.
4.0 CONCLUSIONS AND RECOMMENDATIONS
Our field exploration and laboratory testing programs were developed in order to adequately
address the Geotechnical Investigation Report Requirements presented to us by Washington
Land Design. Exploration procedures and subsurface logs are presented in Appendix A, while
Appendix B presents the laboratory test procedures and test results. Appendix C presents
AASHTO pavement design information and Appendix D presents the Foundation Design
Criteria and Geotechnical Investigation Fact Sheets.
In our opinion, development as proposed is feasible from a geotechnical engineering
standpoint. However, variable near-surface soil conditions, including soft compressible silts
and the high potential for seismically induced loss of shear strength in saturated sandy soils
provide significant performance risk to conventional shallow foundation systems. In our
opinion, the use of drilled augercast piles to support foundation loads for the new building
would minimize the risk of excessive post-construction settlement and transmit foundation
loads through liquefaction susceptible soils. Due to the topography of the site, we anticipate
that relatively minor grading will be required to prepare the site for construction of the building
and peripheral structures. A significant portion of the site soils should be adequate for use
in project fills, with proper moisture conditioning.
4.1 Liquefaction Analysis
As a part of this study, we performed a site specific and detailed liquefaction analysis for the
soil conditions revealed in our borings. Liquefaction may be described as a sudden loss of
shear strength due to the sudden increase in porewater pressure caused by shear waves
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17 October 1995 Page 6
associated with earthquakes. Based on our liquefaction analysis, we estimate that there is
a risk that liquefaction would occur between a depth ranging from roughly 7 to 22 feet below
the existing ground surface during a design level earthquake event, as discussed below.
Laboratory testing was completed as a part of this liquefaction analysis, the results of which
are attached or indicated on the boring logs, as appropriate.
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Based on the Uniform Building Code (UBC) guidelines, seismic analysis should be based on an
event having a return period of approximately 500 years. According to available historical
data, this return period within the Seattle area would be associated with an earthquake of
approximate Richter magnitude 7.5. The peak ground surface acceleration produced by an
earthquake of this magnitude was assumed to be 0.20g at the subject site, which corresponds
with the locally accepted acceleration values for fill or alluvial material.
Using these seismic parameters, we computed safety factors against liquefaction for the
various soil layers below the water table using an analysis method developed by Seed and
Idriss. Our analyses revealed a high probability of liquefaction (safety factors ranging from
< 1 to 1.25) within the silty sands, sands, and sandy gravels between 7 feet to 22 feet in
depth. The deeper gravel and sand soils were found to be non-susceptible to liquefaction
owing to their higher density and coarser gradation.
Based on our liquefaction analysis, there appears to be a high risk of liquefaction occurring
within the loose silty sands and sands below anticipated high groundwater levels
(approximately 6 feet in depth). Liquefaction within these soils could produce surface
disturbance in the form of lateral spreading, subsidence, fissuring, or heaving of the ground
surface, which could result in cracking, settling or tilting of the building or other structures.
Volumetric strain on the order of 2 percent could be possible which correlates the potential
settlements of about 1 %: to 3 inches of settlement, depending on the thickness of liquefiable
soils. Due to the potential for liquefaction, as well as the relatively high settlement potential
for foundations constructed above the shallow site soils, augercast pile foundation systems
are recommended which transmit foundation loads to more competent soil units at depth.
4.2 Site Preparation
Prior to site grading, provisions should be made to intercept and remove surface water during
construction, including maintaining the existing surface water management features in
working order to the greatest extent possible. Once surface runoff and any groundwater
seepage are controlled, all vegetated areas of the site to be developed should be stripped of
topsoil, and vegetation. We estimate that stripping depths will vary from approximately 6
inches to 10 inches in undeveloped portions of the site. Deeper topsoil and roots should be
anticipated and removed around and beneath tree rootballs, and in other relatively heavily
vegetated parts of the site.
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We recommend that the existing paving be left intact to provide all weather construction
surface, except where it will interfere with other construction activities. Demolition of
buildings on the site should include removal of all walls,floors,foundations,and buried utilities
within the footprint of the new building or in footprint areas of any other permanent
structures. All utility work, including demolition or decommissioning, should be performed in
accordance with applicable Federal, State, and local regulations. Localized excavations below
finished excavation grades made for demolition or removal of utilities should be backfilled with
structural fill as outlined in the following section of this report. After stripping, the exposed
soils should be graded and compacted as outlined in the following sections of this report.
We recommend that the building pad and paving subgrade areas be scarified, moisture
conditioned, pre-rolled and compacted with a roller or other suitable heavy equipment to a firm
and non-yielding condition in order to achieve a minimum compaction level of at least 92
percent of the modified Proctor maximum dry density (in accordance with ASTM:D-1557 test
procedure) in the upper one foot of exposed subgrade soils. The suitability of prepared
subgrades should be evaluated during pre-rolling by a representative of AEE. Soils which
become disturbed due to the removal of buried utilities or other items should be moisture
conditioned and recompacted to a minimum of 92 percent of the modified Proctor maximum
dry density to the full depth of disturbance.
Because of the high silt content of some of the soils, the bulk of the near surface site soils
are moisture sensitive. The silty soils are highly prone to disturbance when wet. To reduce
site disturbance, the contractor should minimize traffic above the prepared subgrade areas.
During wet site conditions, the use of a working surface of quarry spalls or sand and gravel
may be required to protect the subgrade, especially from vehicular traffic. Earthwork during
wet site conditions may result in disturbance of the site soils and may require imported backfill
or soil drying and recompaction to repair the disturbed areas. If earthwork takes place during
freezing conditions, we recommend that the exposed subgrade be allowed to thaw and be
recompacted prior to placing subsequent lifts of structural fill.
4.3 Structural Fill
All structural fill placed in the building area as well as under parking and sidewalk areas, and
for backfill of subsurface utility trenches should be placed in accordance with the
recommendations herein for structural fill. Prior to the placement of structural fill, all surfaces
to receive fill should be prepared as previously recommended. Structural fill should be placed
in lifts not exceeding 8 inches in loose thickness. Individual lifts should be compacted such
that a density of at least 92 percent of the modified Proctor maximum dry density is achieved.
We recommend that a representative from our firm be present during the placement of
structural fill to observe the work and perform a representative number of in place density
tests. In this way, the adequacy of earth work may be evaluated as grading progresses.
Washington Land Design 11-10521-00
17 October 1995 Page 8
Due to the condition of the soils encountered within the proposed building pad, we
recommend that a mat of structural fill be constructed beneath all slab on grade floors in order
to provide more uniform support. The mat of structural fill should be a minimum of 18 inches
in thickness and consist of pit-run sand and gravel or crushed recycled concrete which can
be compacted to a minimum of 92 percent of the modified Proctor maximum dry density.
Above the mat, we recommend placing an additional 2 feet of surcharge fill which is nearly
equivalent to the design floor loads in order to preconsolidate the settlement sensitive soils
encountered in some of our borings. The mat and surcharge soils should be completed at
least 30 days prior to construction of the floor slabs.
In our opinion, the most of on-site soils are suitable for structural fill use provided moisture
is adjusted for compaction to a minimum of 92 percent of their modified Proctor maximum dry
density. An exception would be silty soils encountered in boring B-1 which consists of soft
silt. The remainder of the site soils would be difficult to use for structural fill except during
drier periods of the year when the moisture content can be carefully controlled. Even during
the summer, delays in grading can occur due to excessively high or low moisture conditions
of the soils or due to precipitation. Scarifying and watering or drying of the soils may be
required for filling with the site soils. If wet weather occurs, the upper wetted portion of the
site soils may need to be scarified and allowed to dry prior to further earthwork. Soil used for
structural fill should contain no particles greater than 6 inches in diameter and be free of
organics and other deleterious materials.
The suitability of soils used for structural fill depends primarily on the gradation and moisture
content of the soil when it is placed. As the fines content (that portion passing the U.S. No.
200 sieve) of a soil increases, it becomes increasingly sensitive to small changes in moisture
content, and adequate compaction becomes more difficult or impossible to achieve. Soils
containing more than about 5 percent fines by weight, such as the majority of the site soils,
cannot be consistently compacted to the recommended degree when the moisture content is
more than approximately 2 percent above or below optimum. Drying of the site soils may
only be accomplished during favorable dry weather. We therefore recommend that grading
on this site be scheduled for the driest time of the year, if at all possible. We also recommend
that the contractor anticipate significant, but unavoidable commitment of effort to adjust the
moisture content of site soils for reuse in compacted fills. If it is not possible to complete the
earthwork during dry weather, the design team and general contractor should anticipate that
a significant portion of the site soils will not be available for reuse as fill for utility backfill or
mass grading. When moisture conditioning of the soils is required, we recommend that the
soils be blended to provide a uniform moisture content throughout the affected soils.
4.4 Utility Trenching and Backfilling
We recommend that utility trenching, installation, and backfilling conform to all applicable
Federal, State, and local regulations such as WISHA and OSHA regulations for open
excavations.
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In order to maintain the function of any existing utilities, we recommend that temporary
excavations do not encroach upon the bearing splay of existing utilities. Likewise, utility
excavation should not encroach on the bearing splay of footings or floor slabs. This bearing
splay should be considered to begin 3 feet away from the widest point of the pipe or
foundation and extending downward at a 1 H:1 V slope. If, due to space constraints, an open
excavation cannot be completed without encroaching on a utility, we recommend shoring the
new utility excavation with a slip box or other suitable equipment.
We recommend that all utility subgrades be firm and unyielding and free of all soils which are
loose, disturbed or pumping. Such soils should be removed and replaced, if necessary. All
structural fill used to replace overexcavation soils should be compacted as recommended in
the structural fill section of this report.
We anticipate that the majority of excavations for underground utilities would be within wet
soils of varying composition. Consequently, most of the soils will not likely be suitable for
reuse as structural fill due to their composition and/or moisture content. Structures such as
manholes and catch basins which extend into soft soils should be underlain by 12 inches of
granular fill soil compacted to 92 percent of the modified Proctor maximum dry density . This
granular material could consist of either crushed rock, sand and gravel pit-run, quarry spalls,
or coarse crushed concrete. Where water is encountered in the excavations, it should be
removed prior to fill placement. Alternatively, quarry spalls or pea gravel could be used until
above the water level. It may be necessary to place a geotextile fabric over the native
subgrade soils if they are too soft, to provide a separation between the bedding and subgrade
soils.
Moderate groundwater seepage with associated soil caving should be anticipated for
excavations extending into the wet fill and native soils. Dewatering should be designed and
maintained by the contractor. Temporary dewatering appears necessary for deeper
excavations. Depending on the season of the work, groundwater seepage elevations may be
higher than those encountered in our borings. During winter and spring, it is likely that
dewatering will be required for most excavations below 5 or 6 feet.
After firm subgrades have been achieved, we recommend that a minimum of 6 inches of
bedding material be placed in the trench bottom. Bedding material for rigid and flexible pipe
conform with Sections 9-03.15 and 9-03.16, respectively, of the 1994 WSDOT/APWA
Standard Specifications for Road, Bridge and Municipal Construction. All trenches should be
j wide enough to allow for compaction around the haunches of the pipe. Otherwise, materials
such as controlled density fill or pea gravel could be used to eliminate the compaction
required.
Backfilling for the remainder of the trenches could be completed utilizing select granular fill.
Compaction of backfill material should be accomplished with soils within t 2 percent of their
Washington Land Design 1 1-1 0521-00
17 October 1995 Page 10
optimum moisture content in order to achieve the minimum compaction levels recommended
within this report. In addition, we recommend that a representative of AGRA be allowed to
perform field inspections and density tests on all backfill to verify compliance with the
recommendations contained within this report.
4.5 Foundations
We recommend that foundation loads for the new building be supported on a system of drilled
augercast piles. This is due to the occurrence of soft, compressible soils beneath portions of
the proposed building, the susceptibility of loose, saturated sands to liquefaction during a
design earthquake,and the general variability of the soils across the site. Slab-on-grade floors
can be supported on site soils with proper remedial preparation. Small, ancillary structures,
such as landscape retaining walls shorter than about 5 feet could be supported on shallow
foundations.
4.5.1 Shallow Foundations
The following shallow foundation recommendations pertain to non-building foundations. All
footing subgrades should be compacted to at least 92 percent of the modified Proctor
maximum dry density, which may require scarifying the upper 6-inches and drying the soils.
If soft fine grain soils are encountered, it may be necessary to overexcavate the subgrade in
order to provide a more uniform bearing surface. We anticipate that overexcavations on the
order of 18 inches would be suitable to provide uniform support of foundation elements. We
recommend that foundations be designed for maximum allowable bearing pressures of 1,500
pounds per square foot (psf). This pertains to footings that are a minimum of 18 inches wide,
bear on undisturbed native soil or structural fill, and are a minimum of 18 inches below the
lowest adjacent finished exterior grade for frost protection. The recommended allowable
bearing pressure may be increased by one-third to resist transient, dynamic loads such as
wind or seismic forces. We recommend that all footing excavations be observed by a
representative of AEE prior to concrete placement, to confirm the condition of bearing soils.
Assuming the foundation elements are founded in the recommended bearing soils, we
estimate that total settlement would be less than 3/4 inch with differential settlement on the
order of 1/2 inch or less. The majority of the settlement should occur during the initial loading
of the foundation, however, if any undisturbed or soft soils are left within the footing area
prior to concrete placement, settlements may be increased substantially. Based upon the
nature of the soil, and laboratory tests, it is our opinion that the subgrade soils exhibit a low
potential for swelling.
i
4.5.2 Pile Foundations
We recommend that building footings be supported on augercast piles. An augercast pile is
formed by drilling to an appropriate pre-determined depth with a continuous-flight, hollow-
stem auger. Cement grout is then pumped down the stem of the auger under high pressure
I
Washington Land Design 1 1-1 05 21-00
17 October 1995 Page 11
as the auger is withdrawn. The final result is a cast-in-place pile. Reinforcing can be lowered
into the unset concrete column to provided lateral and/or tension capabilities.
Pressure grouting methods typically result in a grout column diameter in excess of the nominal
diameter of the drilled hole. The soft and loose soils on the site could provide difficulty to
augercast pile construction due to grout loss into the loose soil strata. In order to prevent
grout loss and excessive grout volumes, we recommend that the contractor be prepared to
provide temporary casing, if required by soil conditions encountered during pile installation.
We anticipate grout volumes within the bearing soil to be on the order of 1 % times the
nominal volume of drilled holes or more. The contractor should be required to stagger the pile
grouting and drilling operations, such that all completed piles within 10 feet of the pile being
drilled have set for at least 24 hours.
Augercast piles would gain their vertical compressive capacity mainly from side friction
between the pile and the native soils with contribution from end-bearing. Vertical uplift pile
capacity will develop as a result of side friction between the pile and the adjacent soil, along
with the weight of the pile. Augercast piles should extend a minimum of 10 feet into suitable
native soils with a SPT N-value of 20 or more, and have a minimum length of 27 feet.
Augercast pile unit capacities for skin friction and endbearing are presented in Table 1 below.
The vertical pile capacities presented assume that adjacent piles are located at least seven pile
diameters apart. If piles are located closer together, a reduced pile capacity should be used
to account for pile group effects. We would be pleased to provide capacities for specific pile
group arrangements,if requested. Lateral augercast pile capacities are also presented in Table
1 for some of the possible diameters. The allowable lateral capacities are based on fixed head
conditions and limiting the deflection to '/2 inch.
Because augercast piles are drilled, obstacles such as concrete or rocks in the subsurface can
cause difficult installation conditions. The contractor should anticipate that some larger rocks
will be encountered in gravelly horizons, and concrete rubble could be encountered within the
footprint of the existing building to be demolished. It is possible that obstacles encountered
during drilling the piles would require relocation of piles at the time of construction if
impenetrable obstacles are encountered at planned pile locations. It will be necessary to
periodically remove the pile auger from the hales during drilling in order to verify depths of the
various soil types, and penetration into the bearing soil layer.
We understand that the proposed building will be designed for the following typical structural
loads as presented to AEE in the Geotechnical Investigation Specifications and Report
Requirements. Based upon these values, we have developed allowable compressive capacities
for augercast piles. The recommended pile lengths and associated allowable capacities are
presented in Table 1 . The allowable capacities and associated pile lengths presented have
been developed to minimize the number of piles and the amount of material used in
construction of the pile foundation system.
Washington Land Design 1 1-1 052 1-00
17 October 1995 Page 12
TABLE 1
ALLOWABLE CAPACITIES OF AUGERCAST PILES
Pile Diameter Pile Length Allowable Allowable Allowable
(Inches) (feet) Compressive Uplift Capacity Lateral
Capacity (tons) (tons) Capacity
(tons)
12 29 21 5 4
12 33 25 8 4
12 39 27 10 4
16 27 25 7 6
16 37 32%: 11 6
16 40 35 14 6
4.6 Slab-On-Grade Floors
Slab-on-grade floors can be constructed above a layer of compacted structural fill placed
above properly prepared native soil. Slab-on-grade floors should be founded on compacted
structural fill constructed in accordance with our recommendations outlined in the structural
fill section of this report. We recommend that the floor slab be underlain by a minimum
thickness of at least 18 inches of compacted granular fill. To minimize post-construction
settlement of a slab on grade floor, we recommend placing an additional 2 feet of temporary
surcharge fill (which is nearly equivalent to the design floor loads of 125 psf) in order to
preconsolidate the settlement sensitive soils encountered in some of our borings within the
building pad. Construction of the mat and surcharge soils should be completed at least 30
days prior to construction of the floor slabs.
Once the surcharge fill is removed, we recommend that 6 inches of free-draining granular
material be placed over the building pad to serve as a capillary break. The fines content of
the capillary break material should be limited to 3 percent or less, by weight, when measured
on that portion passing the U.S. No. 4 sieve. We further recommend that at least 50 percent
of the capillary break material be retained on the No. 4 sieve. Aggregates similar to those
specified in WSDOT 1994 Standard Specifications for Road, Bridge, and Municipal
Construction, listed under specifications 9-03.12(4), 9-03.15 or 9-03.16 can be used for
capillary break material provided they are modified to meet the fines content recommendation.
If possible, the capillary break material could be incorporated into the 2 foot thick surcharge
layer. A vapor barrier between the capillary break and floor slab is not necessary provided the
recommended gravel section is constructed below the floor slabs.
1
Washington Land Design 1 1-1 05 21-00
17 October 1995 Page 13
4.7 Backfilled Walls and Retaining Structures
The lateral soil pressure acting on backfilled walls will primarily depend on the degree of
compaction and the amount of lateral movement permitted at the top of the wall during
backfilling operations. If the wall is free to yield at the top an amount equal to at least 0.1
percent of the height of the wall, the soil pressure will be less than if the wall structurally
restrained from lateral movement at the top. We recommend that an equivalent active fluid
pressure of 35 pcf be used for yielding walls and an at rest equivalent fluid pressure of 55 pcf
be used for non-yielding backfilled walls. These equivalent fluid pressures assume the backfill
is compacted to approximately 92 percent of its modified Proctor maximum dry density. We
recommend that we be allowed to review the design values and modify them, if necessary,
if they are to be applied to walls greater than 12 feet in height.
The above equivalent fluid pressures are based on the assumption of a uniform horizontal
backfill and no buildup of hydrostatic pressure behind the wall. Surcharge pressures due to
sloping ground, adjacent footings, vehicles, construction equipment, etc. must be added to
these values. For loading docks, surcharge loading on the floor slab above the dock will result
in a horizontal, uniformly distributed surcharge on the wall equal to 40-percent of the
distributed vertical loading. We can provide surcharge criteria for other loading conditions
behind the loading dock wall, if requested. We recommend a minimum width of 2 feet of
clean, granular, free-draining material should extend from footing drains at the base of the wall
to the ground surface, to prevent the buildup of hydrostatic forces. It should be realized that
the primary purpose of the free draining material is reduction in hydrostatic pressures. Some
potential for moisture to contact the back face in the wall may exist even with this treatment,
which may require more extensive water proofing be specified for walls which require interior
moisture sensitive finishes.
Care should be taken where utilities penetrate through backfilled walls. Minor settlement of
the wall backfill soils can impart significant soil loading on utilities, and some form of flexible
connection may be appropriate at backfilled wall penetrations.
4.8 Drainage Considerations
Some of the site soils have a high silt content and are therefore highly susceptible to
disturbance when wet. Any accumulated surface water on the site should be routed away
from the construction and building areas as much as possible before construction takes place.
Surface runoff should be collected and routed to a suitable discharge point or detention basin.
Deeper excavations on the site, such as for deeper utilities and service pits in automobile
service centers, will encounter groundwater seepage. Due to the granular nature of some of
the subsurface soils, seepage into deep excavations will likely be accompanied by heaving
excavation bases, and spelling of excavation sidewalls. We recommend that any excavations
below groundwater seepage depths be undertaken only when suitable dewatering equipment
and temporary excavation shoring, such as sump pumps and trench slip boxes are available.
All applicable safety regulations regarding shoring or sloping of excavations when worker
l
Washington Land Design 11-10521-00
17 October 1995 Page 14
access is necessary should be followed. Deep excavations should be kept free of water and
kept open no longer than required to complete the foundation or utility work at hand.
We recommend that the building be provided with a perimeter footing drain system consisting
of a 4-inch diameter perforated PVC or ADS pipe, fully enveloped in pea gravel or washed
round drain rock. This pipe should be placed at the footing subgrade elevation or below the
lowest subfloor utilities which might be affected if seepage comes in contact with them and
should drain by gravity to a suitable discharge. Runoff generated from the roof of the building
and from paved surfaces should not be routed into the footing drain system. Instead, they
should be routed via tightline to a suitable discharge location. We recommend that finished
grades around the site route surface drainage away from the building.
4.9 Temporary and Permanent Slopes
Slope stability during excavation is a function of many factors, including: the presence and
abundance of surface and groundwater; type and density of various soil strata; the depth of
the cut; surcharge loading adjacent to the excavation; and the length of time the excavation;
and the length of time the excavation remains open. Consequently, it is exceeding difficult
to preestablish safe and maintenance free temporary slope angles. Temporary slope stability
should be made the responsibility of the contractor, who is continuously on the job site and
able to observe changes in the site soil and groundwater conditions and monitor the
performance of the excavation. We recommend that excavations be adequately sloped or
braced to prevent injury of workmen from local sloughing and spelling. All cuts should be
completed in accordance with applicable Federal, State,and local safety provisions and codes.
For preliminary planning,temporary cuts may be sloped at about 1 .51-1:1 V(Horizontal:Vertical).
Because of the variables involved, these slope angles should be considered preliminary values
for the project planning only. If loose fills, caving conditions, or groundwater seepage or
surface water runoff is present on the slopes, flatter slopes may be necessary. Permanent
slopes above the water table should be planned at an inclination of 2H:1 V or flatter. For
slopes exposed to periodic saturation and rapid drawdown, such as stormwater detention
ponds, we recommend that the interior slopes be configured at a 31-1:1 V angle.
4.10 Seismic Criteria
Seismic design of the structure requires the selection of numerical coefficient of soil structure
interaction, designated "S" of the 1994 addition of the Uniform Building Code, Table No. 16-
J. Based on the soil conditions encountered in the borings at the site and published geologic
mapping, we recommend using an S-factor equalling 1.5 as specified for soil profile type S,.
Soil profile type S„ applies where 20 to 40 feet of soft to medium stiff clay is present. The
1994 UBC, Figure 16-2, classifies the site as being within Seismic Zone 3. Commercial
buildings are categorized as standard occupancy structures with seismic and wind importance
factors (1) of 1 .00.
i
i
Washington Land Design 1 1-1 0521-00
17 October 1995 Page 15
5.0 PAVEMENT DESIGN
Due to the limited area of new asphalt to be constructed, we have based our pavement
recommendations on our experience with similar soils on other projects. It is our experience
that the effective subgrade support for the soils encountered on the site is primarily dependent
on compaction and moisture content of the subgrade. Based on the recommended subgrade
compaction, we recommend designing for the following:
Relative Effective Modulus Effective Resilient
Compaction CBR of Subgrade Reaction Modulus (psi)
92% modified 5% 140 pci . 4500
We have alternate pavement designs for both asphalt and portland cement concrete. All
designs have been prepared in accordance with the widely accepted AASHTO design
methods. We have provided pavement designs for the specified equivalent single axle loads
(ESAL's) presented in the Geotechnical Investigation Report Requirements. These pavement
sections are provided in Table 2, Pavement Design Recommendations. Our design assumes
that the subgrade will be prepared in accordance with Sections 4.2 and 4.3 of this report.
The top 12 inches beneath the pavement surface should be compacted to a minimum of 92
percent relative compaction, using AASHTO T-180 (ASTM D-1557) as a standard.
Specifications for pavements and crushed base/top course should conform to specifications
presented in Division 9, Materials, of the 1994 Washington State Department of
Transportation, Standard Specifications for Road, Bridge, and Municipal Construction. In lieu
of crushed gravel base/top course, 3 inches of asphalt treated base (ATB) can be substituted.
The ATB would provide a more durable wearing surface if the pavement subgrade areas will
be completed prior to the building construction phase.
The following pavement designs are based on AASHTO methods with the preceding
assumptions and address the specifically requested traffic loadings.
TABLE 2
PAVEMENT DESIGN RECOMMENDATIONS
ASPHALT CONCRETE PAVEMENT: 1. 2
Approx. Number Approx. Asphalt Crushed Pit-run or
of Trucks per Number of Concrete Rock crushed
Day (each way) 18 kip design Thickness Base concrete
axles find Thickness Subbase
(1000) had
Standard 2 14.6 2 4 6
Heavy 7 51.1 3 4 8
Washington Land Design 1 1-1 0521-00
17 October 1995 Page 16
PORTLAND CEMENT CONCRETE PAVEMENT: 3
Approx. Number Approx. Number of P.C.C. Crushed Pit-run or
of Trucks per 18 kip design axles Thickness Rock Crushed
Day (each way) (1000) LO-1 Base Concrete
Thickness Subbase
iLELI ind
Standard 2 14.6 5 4 6
Heavy 7 51 .1 6 4 8
Notes:
1 ) All pavement sections were designed using AASHTO design methods.
2) All pavement sections assume an AASHTO reliability level (R) of 85% with a terminal
serviceability
of 2.0 for asphalt concrete, and 2.0 for cement concrete.
3) Concrete design based on a modulus of rupture equal to 500 psi, and a compressive
strength of 4000 psi.
4) Concrete sections assume plain jointed or jointed reinforced sections with no load
transfer devices at the shoulder.
A sample of our design parameters for AC/BASE course section are attached to this report in
Appendix C.
If possible, construction traffic should be limited to unpaved and untreated roadways, or
specially constructed haul roads. If this is not possible, the pavement design selected from
Table 5.0 should include an allowance for construction traffic.
Stabilizing the subgrade with a fabric such as Mirafi 500x or 600x may be necessary during
wet weather construction. Proper geotextile fabrics will maintain segregation of the subgrade
soil and base course materials. If the subgrade soils are allowed to migrate upwards into the
base course, the result would be decreased pavement support. The use of stabilization fabric
will not reduce the necessary base rock thickness, as fabric does not provide structural
strength at such shallow depths. If the subgrade is disturbed when wet, overexcavation may
be required and backfill with import fill.
We anticipate that most of the existing pavement will be overlayed with new asphalt. Due
to the poor condition of the existing asphalt, we recommend a 3 inch thick overly for heavy
sections and a 2 inch thick overlay for standard sections. There will most likely be areas
where the pavement has alligatored significantly to warrant removal or use of an asphalt fabric
to minimize reflective cracking. Products such similar to Amoco Petromat or Petrotac would
be suitable in these areas. Other areas of significant distress may have been caused by
degradation of the subgrade soils due to insufficient crushed aggregate beneath the asphalt
or excessive heavy traffic. In either case, it maybe necessary to repair subgrade soils in some
areas.
Washington Land Design 1 1-1 052 1-00
17 October1995 Page 17
6.0 CLOSURE
The recommendations contained in this report are based on information gathered during our
field studies and on information provided by Washington Land Design. In order to correlate
soil data with the actual soil conditions encountered during construction, and to check for
construction conformance to our report, we recommend that AEE be retained for construction
observation services during stripping, grading, compaction, foundation excavating and other
soils related portions of this project.
At the time this report was written, project planning was in progress, and complete plans and
specifications were not available. We recommend that we be provided an opportunity to
review the final plans and specifications when they are completed, to ensure that our
recommendations have been adequately interpreted and incorporated into the final project
documents.
We appreciate the opportunity to have been of service to you on this project. Please do not
hesitate to contact our office if you have any questions or comments regarding the contents
of this report.
Respectfully submitted,
AGRA Earth and Environmental, Inc.
Bruce W. Guenzler
Senior Staff Geologist 't kS A JO
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02 C e9
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Thomas A. Jones EXPIRES d 27r q
Senior Project Engineer
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Peer, P.E. sS'(01YALE4
Senior Associate
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W0. 11-10521 RENTON RETAIL SITE
OC�AG R A DEAN RWr RENTON, WASHINGTON
r TAYI & Environmwital DRAWN Duw
w 0 120 240 11335 NE 122nd Way, Suite 100 DATE REP 1995 SITE & EXPLORATION PLAN
DRAWING BASED ON PLANS BY BUSH, ROED & HITCHINGS, INC. & WASHINGTON LAND DESIGN. SCALE IN FEET Kirkland,Washington, U.S.,4 98034-6918 SCALE NOTED
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APPENDIX A
SUBSURFACE EXPLORATION PROCEDURES AND LOGS
APPENDIX A
1 1-1 0 521-00
FIELD EXPLORATION
The field exploration program conducted for this study consisted of advancing 19 hollow -
stem auger soil borings at locations within proposed building and parking lot areas. The
approximate locations of the explorations are presented on the Site and Exploration Plan,
j Figure 1 . The locations were obtained in the field by hand taping from existing site features
shown on the site plan provided to us. Locations shown should be considered accurate to the
degree implied by the method used. Interpretive soil logs of the borings and test pits are
presented in this Appendix.
Hollow Stem Auger Borings
The borings were drilled on 21, 22, and 25 September 1994 by a local exploration drilling
company under subcontract to our firm. The borings consisted of advancing a 4-inch outside
diameter, hollow-stem auger with a truck drilling system. During the drilling process,samples
were obtained at generally 5 foot depth intervals. The borings were continuously observed
and logged by an engineering geologist from our firm.
Disturbed samples were obtained by using the Standard Penetration Test procedure as
described in 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. The number of blows required to drive the sampler the final 12 inches
is considered the Standard Penetration Resistance ("N") or blow count. The blow count is
presented graphically on the boring logs in this appendix. If a total of 50 blows is recorded
within one 6-inch interval, the blow count is recorded as 50 blows for the number of inches
of penetration. The resistance, or "N" value, provides a measure of relative density of
granular soils or the relative consistency of cohesive soils.
The soil 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. Samples area generally saved for a period
of 30 days unless special arrangements are made.
The boring logs presented in this appendix are based on the drilling action, inspection of the
samples secured, laboratory results and field logs. The various types of soils are indicated as
well as the depths where the soils or characteristics of the soils changed. It should be noted
that these changes may have been gradual, and if the changes occurred between sample
intervals, they were interpreted.
The groundwater conditions observed during the exploration program are indicated on the
borings logs. These subsurface water conditions were evaluated by observing the moisture
condition of the sample, or the free water on the sampling rods. The depths to static water
should be considered approximate due to the relatively short period of time that the borings
remain open, and because drilling conditions required that water be added to each of the
borings to facilitate completion of the holes.
PRojEcT: Renton Retall Site wo. 17-70521-00 BORING NO. 8-1
SOIL DESCRIMON PENETRATION RESISTANCE Palo I
a Rj �
� 1 0 AL of 1
Location: Exfstfng Parking Lot S of IL
< g Standard Blows per foot Other
Approximate ground surface elevation: Unknown 0 10 20 30 40 50 TESTING
NIE
---------------
Saturated,brown,fine to coarse,sandy GRAVEL
........ ...................................................... .......
with some silt(F710(cuttings)
---------------------------
........ --------------- ................................... ---------
Soft,saturated,mottled gray and brown,fine
sandy SILT(Ali?) .......
......... ....... ............................................. ......
....................................... ....... ....... .......
S-7
. ........... ...... ...............
--- ....... ....................................... .......
...............
....... ................. ............... ...............
- 10 -----------------
Medium --------
dense,saturated,mottled gray, ------ S-2--
gravelly,fine to medium SAND with trace to ............I..... ........ ......I
some silt
............ .......... -- ----------- ......
15
........................ ..... ------- .......
----------------------- ............................... ........
Grades to dense
S-3 noybo
....... ...... ------ ...
- ---------ov OW
Cut to rock*
................ ...............................................
F
....... ....... ............................... ....... ....... .. .
Grades to fir�etc,medium sandy GRAVEL with ....... .............................................. ........
trace to some s#t
- 20 -
S-4
....... .....- ............................. ....... ----- .....
....... .......................--------------- ...... .......
-----------
Grades to very dense
....... ------- ------ ........................ .......
S-5
........i-.... ....... ....... L....... ............... +
T
- 25 Boring terminated at appro)dmataly
24.5 feet ....... ...... ...................................... ....... ..............
Note: Moisture contents noted are not .......... ..................... ....... ...............
representative due to 'wet'drilling
method. ... .............................. ------- ....... -
............... ....... ...................... ....... ...... ................
30- D 20 40 so a 0 too
LEGEND MOISTURE CONTENT
i
Plasticlimit Natural Ljqtidlimit
2 = 2.00-inch OE)zpHL-jpoon sample
AIL
W
Coosmdwater gavel at time of drilling A G R A
Earth & Environmental
11335 NE lZh)d Way,Suite 100
WE No groundwater ancoamered
KWdand,WashWon 98034-6918
Daingmethod: Fluid Rotary Haintrertype: Automatic Date drilled: 21 September 1995 Logged by: BWG
moxcr: Renton Retall Site w.o. 71-70527-00 BORING NO. B-2
SOIL DESCRIPTION PENETRATION RESISTANI C I
I Location: ExstIng Parking Lot S A Page I f I
ad feet Other
Standard Blows per
0 Approximate ground surface elevation: Unknown 0 10 20 30 40 50 TESMG
Pavement
arse, -Wd�VEL ........b
Saturated,brown,tine To�o sandy
........ ....... ....... ........... ....... ....... .......
with some silt 00(cutfings)
— --------------------- ------
........ ...--------------------------- ------- .......
Medlurn dense, wet,gray and brown,fine to
coarse sandy GRAVEL(FYI?) . ....................................... ....... .......
............ ....... ....................................... .......
S-1
................................ .............. ......................
................ ....................... ....... ....... .......
....... ....................................... .......
—-—————————————————————————————- ------- ....................... ............... .......
Very loose,wet to saturated,brown,fine SAND
- 10 with gray,silly strIngers
S-2
J ....... .............................. ....... ....... ......
ATD
............... ....... ............... ..........
............ ........
........ ......... . ........ ...... ............... .......
—------------------------------- .......----------------------- .......----------------
Dense,saturated,gray,fine to coarse sandy
15 GRAVEL with trace silt
............... ....... ............................. ............ ......
--------------- ---------------------------------- ... ....... .......
------- ............................. ........ ....... ................
hum dense, with more relattvely ...... ....... ...............Grades to id i
.............................. ................
more sand
- 20 -
.... . ...... ....... ...................... ...............
s-4 t
Boring terminated at approximately ................................................ ...............
27.5 feet ....... ....... ----------------------- ..............................
............... ........
........ ----- ------
- 25
....... ....... ....................................................-
............... ------- --------------- ......... ...... .......
.... .............................................. ...............
30 -
0 20 40 60 so 100
LEGEND MOISTURE CONTENT
Plastic linnit Narrind Liquid limit
2 2.00-inch OD split-spoon.sarnple Grain sire analysis
WAGRA
C"nadwaWlemlatinscofdrilling
ATT) Earth & Environmental
11335 NE 122nd Way,SUte 100
NIE No groundwater cDcount=d
kIddand,WasWon 9eO34-6918
Drilling method: HSA Hammer type: Automatic Date drilled: 21 September 1995 Logged by: BWG
PROJECT: Renton Retall Slte w.o. 1 1-7052 7-00 BORINGNo. B-3
SOIL DESCRIPTION p� PENETRATION RESISTANCE Page 1
p of 1
Location: Eadsthrg Parking Lot k � so
G v Approximate and surface elevation: Unknown y h 3 Sund10 Blows per foot Other
PP So o to 20 30 sc w ii;sT7NO
0 TAsP haf7 Pavement
— ---------------------
Road Base(518'Crushed Rock)(cuttings) i..-..-.--.-_.........._............. ......._.......
---------------------------
Medium dense,moist,brown and gray,tine to
............... .......:...............;...............4....... ....... .......
coarse sandy GRAVEL with,trace to some silt
S-1
--- ..-------------------------------- ......
5
S-2
............... .......-......... ....i...............
....... ....... .......
........ ........................:........- .. ..
10
S 3 ..... - .. .......
....... .......:..... ---------- ----
i
___ _ ............. .......------- -------- ............_. ...._.
Grades to dense
15 AM
S-4
20
S-5 _............ ------ -------------- _.............
Boring terminated at approxmately .......i....... ..... ;.............................. ---- ...... ........
21.5 feet
25
............... ....... _..._._..._i..- ----' ---.
30 0 20 40 60 Ea too
s LEGEND MOISTURE CONTENT
a
Plasticlimit Natural Liquid limit
e 2.00-inch OD split-spoon sample
w WAGRA
iCxomdwaterlevela uueofd l rag Earth & Environmental
L
! w nit No groundwater eueou wmd 11335 NE 122nd Way,$lute 100
laddand,Wcts"on 98OU-6918
6
Drilling method: NSA lla r type: Automatic Date drilled: 27 September 1995 Logged hy: BWG
PRojEcr: Renton Retail Site w.o. 11-70521-00 BORING NO. B-4
SOIL DESCRIPTION pL g� PENETRATION RESISTANCE Page 1
8 Location: Existing Parking Lot A 0 of 1
o Approximate ground surface elevation: Unknowny p 3 Standard Blows per foot Other
PP gr 0 10 20 30 40 50 TESTING
O 2.5'Aseho7Pavement--- —��
---
Brown,sandy GRAVEL(fafp Ccultfngs) .... .......}...............:....... .......:_._.. ...............
Gray,silty,grovelty SAND(Alp(cuttings)
———————————————————— ---.-t..-- ......` .
Soft, wet,brown,tine sandy SILT,non plastic
5
ZEfh
S'1 L...... .......
- i.....
10 ----------------------
Medium _ ATD
dense,wet to saturated,gray,floe to S p
coarse sari GRAVEL with trace sill ...............`....... -------------
Boring terminated at opprobmately -------------------;-...... ._...._.......
J1.5 feet ............... ............................... ........
----.... .............. ..............................!.......
i
15
i
i....... ....... - ----- ....... ....
20
25
30 0 20 40 60 80 100
s LEGEND MOISTURE CONTENT
s
I2.0o-inch oD.ptio-epoos wopte ® Grain size"yw9 Plastic Emit Natural Liquid limit
OAGRA
it3romdwaer,e"``attime°rdn,ling Earth & Environmental
N/E No groundwater encounmred 11335 NE 122nd Way,Sidle 100
Kirtland,Washington 98034-6918
` Drilling method: NSA lla r type: Automatic Date drilled: 21 September 1995 Togged by: BWG
PROJEcr: Renton Retall Site "` " w.o. 1 1-7 052 1-00 BORtxoNo: 8-5
SOIL DESCRIPTION PENETRATION RESISTANCEE Page 1
Location: bAffng Parking Lot t of I
6 < x Standard Blows Blows per foot Other
Approximate ground surface elevation: Unknown ° 3 0 10 20 30 40 50 Two
i 2.5 ,AsphoffPavement-----------_ NIE
--
Medfurn dense,damp,gray and brown,fine to ........t...............-........- - -:...............+....... .......i.......
coarse sandy GRAVEL with trace to some sfff
......_....... ....... ...............................r....... .......j........
{
S-1
... ......._....... ......................_.......
i
5
.......... *................
............. ....... ...... ......
S-2
10 Boring terminated at appropmately
9 feet
----- -------+.................._......... _. ------
i i
— '--•-- ---... ............................... ....... ......._.......
15
............... ....... .............. ...._. ....._r.......
j------ ---------------------............... ...............i.-----
20
25
...............:.....................-- -----------.-----
i
i
30 0 20 40 60 ao 00
LEGEND MOISTURE CONTENT
Plastic limit Natural Liquid limit
o I 2.00-mch OD split-%p sample
* AGRA
( ondwvlerlevelatruocofdril ng Earth & Environmental
NM No groundwater cncouorered 11335 NE 122nd Way,Sulfe 100
Khldand,Washhglon 9MU-6918
Drilling method: HSA Hammer type: Automatic Date drilled: 21 September 1996 Lugged by: BWG
PmEcr: Renton Retail Site wo. 71-70521-00 BORINGNO.
• SOIL DESCRIPTION 21 PENETRATION RESISTANCE Page 1
iF Blows per foot w Location: Eidsting Parking Lot Standard t r
f 1
Othe
Approximate ground surface elevation: Unknown 10 20 30 40
0 0
so 1FSIING
Asphalt Pavement NIE
-8-rown-,san-dy-G-RA-licL ............... ...... ... ...... . ----------................
(cuttings)
...... ....... ...................... ....... ....... ...............
-------------------
-Gray-,�Wt,silty (cuttings)
...... ...................................... ------- ...............
.... ...................... .............. ............... .......
-------------------------------
5 Medium dense,damp,gray,gravelly,fine to
medium SAND with trace silt S-1
.......... ............................... ...... .......
....... ---- ------- --------...... .......
------------------------------
Dense,moe,gray,One to coarse sandy --------
................................ .......... .......
GRAVEL with some silt
10
............... .......
IT
S 2- t
---- - -- --- ....... ....... ......----------- ...............
Bonng terminated at approkmately
11.5 feet .............................. -------
..............................................t------- .......T.......
15
............... ...................... ....... ------- ...............
....................... ....................................... ...............
4..... ............................................ ...............
F
.......... ...................... ....... ....... ......
20 -
.......................4
.. ........ ....... -- - - - -
............... ..................................................... .......
............... ............................... .......
.............. ............................. ....... -------........
25
...................................................... ........
..................... .......................
............. ...........
4....... ....... ......... ..
30 - 6 20 40 60 so 100
LEGEND MOISTURE CONTENT
i
Plastic limit Natural Liquid limit
2.00.inch OD Tlit-spoon sample
* AGRA
Cra el undwwr level at tine of drilling
AID Earth & Environmental
11335 NE 122nd Way,State 100
WE No gramdwater enwuntered Kirkland,Washington 98034-6918
Drilling method: HSA Ilarnmertype; Automatic Date drilled: 22 September 1995 Logged by: BWG
PRojEcT: Renton RetoU Site wo. 71-10521-00 BORING No. B-7
SOIL DESCRIMON PENETRATION RESISTANCE, page I
of I
le lei of I
Location: ExWing Parking Lot I ' I S A z
to " 0 Standard "low'per 1'3000' Other
Approximate ground surface elevation: Unknown 5o TYSTING
AsphaKPovemenf
S-1 NEE----------- ---
..................... --------------- ....... ......
Loose,damp,brown.Me to coarse,sarx�; pH=6.5
\GRAYS-0Q-----------------
Medium stiff to stiff,wet,grog,fine sandy SILT ............. .......------- .......4...... .......4....... .......I........
with low plasticity to non plastic
....................................... ....... ....... ....... .......
....... ..... ....................... -------------. ................
5
—------------------------------- ................ .............. .......--------------- ... ...............
Medium dense.moist, Me to coarse sandy
GRAVELwith trace to some slit ...... ........ ...... ...... ----- . ..........................
........ .............. ....... .......S-2 i
................
- 10 Boring terminated at appro)dmately
9 feet
....... .......------- -------.......................................
........ ..............................................
............. ....... ....... .......------------------------..............
....... ............... -------............... ....... ......
15
....... -----------------------...... ....... ....... ....... -------
....... ....... ...............------- ....... .......
....... .......................--------------- .......................
....... ....... ............................................ ........
20 -
....... ------------------.................... ............... ------
------- ----- ..............................................
.......... ....... ....... ..............................................
....... ....... ....... .......--------------........................
- 25
---------------....................... ............... ............
....... ............................................... ............
--------------- ....... ...... ....................... ...... .......
....... ....... ...... ................
LL
301 D 20 40 60 so foo
LEGEND MOISTURE CONTENT
Plastic limit k4hazi Liquid limit
2.00-inch OD spli��sample PH-7.0 Soil PH Was
* AGRA
Ckomd�level a time of MIME NMI Resistivity test
ATO Earth & Environmental
NIE No Sw�dwattr=�W" 11335 NE IZ?nd Way,Sulte 100
Kirkland.Washington 98034-6918
Drilling method: HSA Hammer type: Automatic Date drined: 22 September 1995 Logged by: BWG
MjEcr: Renton Retail SIte w.o. 71-10527-00 BomNGNo. B-8
SOIL DESCRIPTION PENETRATION RESISTANCE Page I
Location: E,&HW Parldng Lot A L of
.1 i Standard Bl..s per foot Other
Approximate ground surface elevation: Unknown 0 (0) 10 20 30 40 1 TESTING
50
'Asphalt Pavement NIE
Coosa,moist,brown,-fin-e-S.A-N-D-w-lt-h-some- .............................. -----------------------------------------------
gravel and trace to some slit
-------
..................... ------ -------
S-7
....... .......... ... ;........ ....... ............... .......
-------------------------------
F
Medium dense,wet,gray,silly,Me SAND with
some gravel i
............ ............... ............... .......
....... .... ------------- ---------------- ---------------
------------------------ ....... ........... .......4....... ....... .......
S-2
10 Baring terminated at oppro)dmately
9 feet
------- ------- .............................................. ......
....... ............................. ..... ............... -
-----
---------------- ....... .............. ............... ---------------
................ ....... ............. ....... ...............
15
...... ....... ............... ---------------------- ....... ........
....... ............... ............... ............. ...........
.. .. ....................... ..... ....... .......
- 20 -
...............--------------- ............. .......
--------------- .............. ............. ...............
..............................................................
....... ............................................ .......
- 25
.............................................. ................
....................................... ....... ...............
................4...............------- ------- --------------- .......
............................. ....................... ....... .......
30 - D 20 40 60 30 too
LEGEND MOISTURE CONTENT
Plasticlimit Nannal Liquid limit
2 j 2,00-mch OD split-spoon sanVk
OAGRA
G u,rroundwa 1`vci at tane of dr[Hing
ATD Earth & Environmental
NIE No groundwater encouowe4 11335NE 122nd Way,Suite 100
KIddand,WashhWon 98034-6918
Drilling method: HSA Harntmrtype; Automatic Date dared: 22 September 1995 Logged by: BWG
PRojEcr: Renton Retail Site w.o. 11-10521-00 BORINGNO. B-9
SOIL DESCRIPTION p� PENETRATION RESISTANCE Page 1
w Location: E411ing Parldng Lot AL !� of 1
p y Standard Blows per foot Other
Approximate ground surface elevation: Unknown n a 10 20 30 10 s0 �O
AsphallPavement _____—�� S-I N/E
--- — ------------
Ane to coarse.sandy GRAVEL 01) � ........:....... I..............................:....... .......,.......
'---------------------
----
Loose to medium dense.damp.brown.silty, --.......... ...... .......
........................ ....... _.....!.......
fine SAND with some fine gravel
...............i....... .....--------------------------
.
5
Dense,damp,brown,fine to coarse sandy ............... ....... ..............., .............
;------ ..........
.._.
GRA VEL with some silt
....... ....... ....... ............... ........ .... ....... ....... .......
S2
111111110110
10 Boring terminated at opprobmately
9 feet
....... .......i....... .. .......
15
....... ............... ...............i...............;.......
i
20
......i.-----. ....._ ._...........................-.----. ....._........
25
`� D 20 40 60 80 tW
£ LEGEND MOISTURE CONTENT
a
Plasficlimit Natural Liquid limit
E 2.00-inch OD split-spoon sample
c
m AG R A
Z aroundwa cr level at me of drilling Earth & Environmental
11335 NE IMnd Way."e 100
WE No groundwater encountered KWdand yyashinWon 98034-6918
a
Drilling method: HSA Hammer type: Automatic Date drilled: 22 September 1995 Logged by: BWG
PROJECT: Renton Retail Site w.o. 1 1-7 052 1-00 BORING NO. ' B-10
SOIL DESCRIPTION g< PENETRATION RESISTANCE Page 1
E Location: ExL M Parkin Loi F A 0 of 1
V Approximate and surface elevation: Unknown 3 Standard Blows per foot Other
PP !� o to za so ♦a so 'TESTING
2'AsphottPavement
_CrushedGravelPavemeM&ue1R1Q ------' .....-_....-- -...._i_..... .......:..........._..i....... .._...........
Very loose,wet,brown,silty,tine SAND
i
...... .......L..............................i.......I ......i.......
5 -
S-2
--- ---------------dy — ....... _..... ............._........
Verysoft,saturated,gray,fine sari SILT,
moderatelydlfatont ------ ------- ----- ....-................_... ....... ...._. ....-
.......i....... .......i.............................. --
Aro
10
S-3
—————————————————————————— ............................... .......;....... ------ -------
Medlum dense,saturated,gray,tine to coarse
sandy GRAVEL with slit .......i.............................. ......................
15
S-4
-.------------ ------- .........................;....... ............_.
i
20
S5 ....... ----------------' ........... ;.......
_________ ...... ....... ............._;. - ._... ...........
.....
Grades to dense
25 -
S� ....... ...........--
Boring terminated of oppro)amately .......
26.5 feet ............... ....... ---------- --- ....... ....... ....... .......
30 o za ao eo ea 100
m
LEGEND MOISTURE CONTENT
Plastic limit Natural liquid limit
e 2.u1u1•inch OD Rlit'spom umplo
w 0AGRA
's s c�dw.tu'evetu aaeotaritlag Earth & Environmental
` `! n E No pomdwater eacuuntered 113M NE 122nd Way,Suite 100
KltMand,Washington 98034.691E
Drilling method: Rudd Rotrvy Hammer type: Automatic Date drilled: 22 September 1995 Logged by. B WG
PRoJECT: Renton Retail Slte w.o. 1 1-1052 1-00 BORING NO. 8-11
SOIL DESCRIPTION p� PENETRATION RESISTANCE Page 1
Location: Edsting Undeveloped Area at SW part of site i r 5 ! A of 1
q h < 3 Standard Blows per foot Other
Approximate ground surface elevation: Unknown — y 0 to 20 30 40 so TFSnNG
0 __G_rowSurfaceandTopsoil ____________
------
Loose,moist,tan,silty,fine SAND with trace fine --..._....... ....._,...............i...-...........
1....... ....... .......
gravel
................ ........................... _ .
f 5
S-1
�n... ....................... ................ ...............
—————————————————— —————— ------- --------------:...............;...............:....... ....... .......
Loose,saturated,gray,fine SAND with Trace silt
10 AID
S 2 .........................
_ -.....1.
Boring terminated at approbmately i i....... ....... .......
17.5 feet ....... ....... ....... ....... .......--------------- ....... .............
15
20
25
30 0 20 40 ao sa too
LEGEND MOISTURE CONTENT
Plastic limit Natural liquid limit
`o I 2.00-wh OD split-spoon samete /�
w 4DAGRA
s camdwr«levelat tone°rddluag Earth & Environmental
w gtor.dencountered 11335 NE 122nd Way,Suite 100
gMdand,Wastlktgton 98034-6918
¢ Drilling method: HSA hammer type: Automatic Date drilled: 22 September l M Logged by: BWG
PROJECT: Renton Retail Site w.o. 11- 10521-00 BORING NO. B- 12
SOIL DESCRIPTION PENETRATION RESISTANCE
P290 I
Location: Ddsting Parking Lot A
I
X Standard Blows per foot Other
Approximate ground surface elevation: Unknown U
0 10 20 30 40 s0 TES'rING
_Asphalt Pavement NIE
-------------
Very loose,damp,gray,fine SAND with trace ........-------- ------- ---------------........... ... ..........
some s#t
....... ....... ....................................... .......
....... .......................t....................... ...............
S-1
..... ....... ............................... ....... ....... -------
5
Grades with thin silty stringersi------------------- ----------------------------------- ---------- ....
............. ....... ....... .......
------ --------------............... ....... .
4
S-21 I I ....... .....-
- 10 Boring terminated at cpproxdmotely
9 feet
.............. ....... . ............... -------
...... ....... ...... ............................ ..............
------- ------- ....... ....................... ...............
------- ------- ....... ....................... ............... .......
- 15
------- ------- ------- ...................... .......t.......
....... ....... ....... ....................... --------------
....... ....... ------- ....... ....... ....... ..............
------- ....... ....... ----- ............... ....... .......
20 -
................ .............................................. ..........
....... --------------- -------............... .. ....... .......
....... ...................................... ....... .......
------------------------------ ------- -------......
- 25
------- --- . ................ ............. .......
....... ... ....... ..... ..... . ............. ...............
................ .......4....... ............... ...... ....... ..............
.... ............... ................ .............. ...............
30 0 20 40 60 Be 100
LEGEND MOISTURE CONTENT
Plastic limit Natural Liquid limit
2 2.00-inch OD split-spoon sample
AGRA
'W Groumdw.tcr level at time of drilling *
ATD Earth & Environmental
NIE No grottndws�ez�utwmd 11335 NE 122nd Way,Suffe 100
Kirkland,Washington 98034-6918
Drilling method: HSA Hammer type: Automatic Dam drilled: 22 September 1995 Logged by: BWG
momcm Renton Retail Site w.o. 1 1-1052 1-00 BORINGNO. 8-73
SOIL DESCRIPTION y g PENETRATION RESISTANCE Page 1
Location: Dozer Troll, West edge of Site of I
p < < o k
a 3 Standard Blows per foot Other
Approximate ground surface elevation: Unknown " ti t7 0 10 20 .w +0 50 "VINO
2_AsphaltPavement-- . _ _ __ ..
------------
molst,
Loose, brown,s11ty,tine SAND with some ..... j....... ....... .. .........................._....... ... .. . ..
gravel to gravelly(cuttings)
............................ ....... ....... .......
5 Very loose,damp,brown,gravelly,fine to
medium SAND with some sit S"1
————————————————————— — .... . ........ ....... ...............;...............
Very loose,saturated,brown and gray,fine ATD
1 O SAND with trace to some silt,very dllatont
S-2
I
i
15
_ ___ ___ S3
Medium dense,saturated,gray and brown,fine
to coarse sandy GRAVEL with trace slit ....... ....... ...... ...............--------------- ------- ....... ......
.
20
S'4 ............... . _........-------'.......................
Grades to dense wtth relatively more sand
25
S-5
Boring terminated at approidmotely !.......
26.5 feet ------- ..._ -
--- --- _ _i............... ...............?.......
30 0 20 40 W EO too
s LEGEND MOISTURE CONTENT
Plastic limit Natural liquid limit
`o = 2.00-inch OD split-spoon sample
c
ALAGRA
Groundwater Ievel a[time of drilling Earth & Environmental
t
11335 NE 122nd Way,Sulfe 100
w WE No groundwattr encountered
aridand,Washhgfon 98034-6918
i a
Dollingmeuhod: NSA lla rtype: Automatic Date drilled: 22September 1995 Logged by: BWG
PRojEcT: Renton Retail SIte wo. 11- 10521-00 BORING No. B-74
SOIL DESCRIPTION PENETRATION RESISTANCE
Location: Dozer Trap,South edge of Site A
48 IL of
Standud Blows per foot Other Pageo
Approximate ground surface elevation: Unimown I --
0 10 20 30 40 50 IRSTING
GrasslTopsoll
----------------------
Very loose to loose,damp,light brown,silty,fine ..... ...................... ............. .
..............
SAND
............... ------- ---- -------............................... .......
....... ....... ......... ....... ....... ........ ..............
....... .............................................. ....... ......
5
S-7
..... ---- --------------------------------------4 . .......
—————————————————————————————- ..... ................................................
Loose,wet to saturated,brown,fine SAND with
trace to some silt,moderato to very allatant . ...... ............................. ....... ....... ......
1W
ATD
....................................... ....... .......
10
S-2
-------
--------------------- ------------ -------4------- ------- .......
— --————————- ......................1....... ...................... ....... ...............
Loose,saturated,gray,fine to medium SAND
with trace siff ............. ....... ------- --------
------ ----- ----- ------
15
............................................. -------
...... ....... .......................
------------------------------
Medium dense to dense.saturated,gray,fine
to medium GRAVEL with some fine to coarse -------
-----------------------
sand and trace to some silt
----------- ............. ....... .............
20
S-4
.......... ....... ........ ------- ------- .......-------
..... ------- ........ . ............... ...............
--- ------------------.......
-----------
Grades to dome
.......... ------- .............................. ..... .......4........
-25
S-5
....... ------- ...... -------- ................
............. ................ ................
Boring terminated at oppro)dmotely
265 feet .............. ------ ------- ....... ....... .......
..... ...... .............................. -------------- ........
30 -
D 20 40 60 80 100
.9 LEGEND MOISTURE CONTENT
Pw6climit Natural Liquid limit
G,.m.su.naly
2.00-inch OD split-spoon sample
* AGRA
'W Groundwater level at e of dhIlLag
ATD Earth & Environmental
NIE No groundwaterencountered11335 NE 122nd Way,Stine 100
01dand,Was"on 98034-6918
Drilling method: HSA llarnmertype: Automatic Date drilled: 22 September 1995 Logged by: BWG
PROJECT: Renton Retall Slte w.o. 11-70527-00 BORINGNo. B-15
j a SOIL DESCRIPTION g PENETRATION RESISTANCEE Page 1
Location: Edsting Parking Lot <
< 3 Standard Blow&per foot Other
0 .. Approximate ground surface elevation: Unknown " h a 0 10 20 30 40 so 1
0 AsplrollPovement _____________��
Brown,gravelty SAND(R ................ ....._ .._........................_ ....... _._.._.......
Very Bose,wet to saturated,gray,silty,line to i..............................i....... ....... .......
medium SAND with trace fine gravel(OVM
OPPm) ......-------- ....................... ....... .......
5
S-1 --....... ......._..............................i....... .......
--------- ...... ....... ._.._ ...............;.__................ .......
Loose,saturated,gray,graveNy,fine to coarse
10 SAND with some silt with silty stringers(OVM 0 -
pprn) ATD
S2 ... ........ - ...._........._....._....... ....... .......
Boring terminated at approximately . .... .._._ ......
11.5 feet _............. ....... .................. ...... ...... .... .......
15 -
20
25
--....»....... ....... ............._i...............;....... ................
i
30 0 20 sa so so 100
LEGEND MOISTURE CONTENT
I inch OD Id- a OVM-]feadrpace method mee&uromen[ Plastic limit Natural Liquid limit
2.00-
W spoon sample
i - of organic vapor;made with
y toe.photoionnation deteclod A G R A
s An) Gn mdwater level a[thne of drilling Earth & Environmental
w we No 11335 NE 122nd Way,Sulte 100
grgtadwaw enoattn[etea Klrldand,Was lllr oon 96034-6918
a
Drilling method: HSA Hammer type: Automatic Date drilled: 25 September 1995 Logged by: BWG
PRojEcT: Renton Retail We wo. 77-10521-00 BoRiNGNo. B-16
SOIL DESCRIPTION PENETRATION RESISTANCE Pale Be I
A, p
It Location: E)dstJngParking Lot sO IL
4 Standard Blowa per foot Other
Of 1
Approximate ground surface elevation: Unknown 0 Q
a 10 20 30 40 M TESTNG
Asphalt PqVeTff Wd ----------
NIE
Brown,gravelly SA RAD
.......................d
....... ............. .............. ....... .......
-------------------------------
Loose,damp,gray,gravelly,Me to coarse ....................... ...................................... .......
SAND with trace to some sift(OVM 0 ppm)
............................................. ....... ......
S-1 T—
............................... ....... ....... ......
-------------------------------
Medium dense,moist,gray,flne to coarse, ..................... ............................... ............... ......
sandy GRAVEL w/M trace sift(OVM 0 ppm)
............... ............................. ....... ------- .......
............... . ............................ ........................
S-2
- 10 Boring terminated at apprcodmately
9 feet
....... ........... ................................. .......
.................... .................. .......
.... ................ .......................................
............. ............................... ............... .......
- 15 -
............... -------4...................... ....... ....... ...............
....... .............. .......------- ------- .... ...............
....... ....... ...... ............... ....... ....... ....... .......
------- ....... ...................... ....... --------------------
20 -
............... ...............----------------------- ..............
...................................... --- ......
.... ....... ............... .............. ....... ....... ......
.... ....................................... .. ................
- 25
........................................ ..............
...... ....... --------- ...................... ....... ....... .......
....... ....... ...............i...............i...._. ....... .......
....... ....... ............... .............. ....... ..............
30 - 0 20 40 6 1 0 so 100
LEGEND MOISTURE CONTENT
Plastichmit Natural Liquid lirmit
0VM-lkadsp�=d�.d �m=nt
2.OG-inch OD spbt-q�samplo
of organic vapors,made with
locv photai."fi.n
WAGRA
C�ndw�lcvcl a time of drilling
AM r Earth & Environmental
11335 NE 122nd Way,Sulfa 100
NIE No groundwater encountered
KMdand,WashhWon 98034-6918
Drilling method: HSA stammer type: Automdfic Date drilled: 25 September 1995 Logged by: BWG
PROJECT: Renton Retall Site w.o. 1 1-7 052 7-00 BORINGNO. B-77
x Z- SOIL DESCRIPTION � ETRATION RESISTANCE page l
t Location: E4ting Parking Lot < of i
pP ground y y y ta7 3 o Standard Blows perf t Other TESTING
Approximate and surface elevation: Unknown—' 10
0 �As 12a Pavement
C_ru_sh_e_dRoc_k_Pave_mentBase(AtD -------- :.. .............._.......:....... ......._.......
Brown,gravelly,line to coarse SAND 00
-- ------
Loose to medium dense,damp,brown,line to
coarse sandy GRAVEL with trace to some silt r....... .......-..............................-....... .......=......
.
5 wco of
S-1 MY
d.
......_.._.... ...._........__.. sy _
Grades to loose wfth trace silt ...... ....... .......}. ......._.................. ....... ...._. .......
10
S-2
----........ ....... ............._....._.......>...... ....... .......
ATD
-----------------------------
15 Very loose,saturated,brown,tine SAND with
trace silt,very allatont S-3
------------------------------- .....
;...... ....... ............................... ................
.......
Medium dense,saturated,brown,line to coarse
sandy GRAVEL with trace to some slit .._.......... .....<.............................. ....... ......._.......
20
S-q ............ ...... ........................_.i....... ....... .......
Boring terminated at opprobmotely — = ----- .._..--.......
21.5 feet ........_..... ....... ......._.......
25
30 o 20 40 so ea tin
LEGEND MOISTURE CONTENT
Plastic limit Natural Liquid limit
`o I 2.00-ock OD Rla-spoon semplo //��
`� AGRA
m = afOmd"""'`"`'a"�COt�"�g Earth & Environmental
NIF No groundwater encountered 11335 NE 122rxi Way,State 100
Kirkland,Washington 98034-6918
Drilling method: HSA llar r type: Automatic Due drilled: 25 September 1995 Logged by: BWG
PRolscr: Renton Retail Site w.o. 1 1-1052 1-00 BORING No. B- 18
SOIL DESCRIPTION w g PENETRATION RESISTANCE page t
Location: Cat Road,South part of Slle xg of 1
�- y a 3 Standard Blows per foot Other
Approximate ground surface elevation: Unknown y o p rn 20 00 40 50 TESTING
0 Gross Surface and To soA
-------------e---------------
Loose,damp,brown,silty,gravelly,fine SAND !....... ....... ......
................ ............... .
5
S-1
————————————————————————————— -------:,...... .......}........................_...._....... ...............
Very loose,wet to saturaaed,brown,silly,fine
SAND,moderately dilatont }----------------------- _-------
10
S-2
........'....... ....... ...................................... -
ATD
15 Medium dense,saturated,gray,fine to coarse
sandy GRAVEL with trace sill S_3
i
20
S-4 .. ...... - `-------------+..._.. _..... .......
Boring terminated at appro)dmately
21.5 feet ....... ............................. ....... ...............
25
30 0 20 40 ca 80 100
LEGEND MOISTURE CONTENT
€ T Plastic limit Natural 110d limit
`o I 2.00-meb O➢split-spoon sample
w * AGRA
n� Groundwater level at timc of drilling Earth & Environmental
11335 NE 122nd Way,Sulle 100
N/E No groundwater cocouotertA arldand,Was"on 9WU-6918
c�
Drilling method: HSA tlatm er type: Automatic Date drilled: 25 September 1995 Logged by. 8WG
PROjEcr: Renton Retail Site wo. 11-70521-00 BORING NO. B-19
PE SOIL DESCREMON A NETRATION RESISTANCE Page 1
8Location: Cat Road, West part of Site At E of 2
Standard Blows per foot Other
Approximate ground surface elevation: Unknown 0 10 20 30 40 50 1MING
0 GrasSIDL& wt� Tqm—Sutfoce oil
L ——————— .
— —
Loose,moist,mottled gray and ton,silly,fine .............. ... ................................ ...... ..
— . ...
SAND
....... ...................................... ....... ....... ......
. .............................................. .......
....... ...................................... .......................
.5 ✓
.......................
............... ....................... pH=6.3
... .. ...................................... ...............
+
-------
- ___-___---- ........ .... .............................................. .......--------
Grades to very loose,saturated,with trace silt,
10 very d1lortant ATD
S-2
... ....... ............. ------ --------
..............................4....... ....... .......
.............................. ------- ---------------
-————————————————————————————--
- 15 Medium dense,saturated,gray,Me to coarse,
sandy GRAVEL with trace to some slit
S-3
..... ... ......4...................... ...............
............... ............. ................. ....... ................
--------------- ---------- . ....................... ....... ...............
............... ...... ................
- 20 -
S-4
...... ....... ...... .....AL.................... ------- -------.......
............ .............. ..................... .......
......... ........................... ...............
------------ -----------... .... .......... ...... ....... ......
- 25
Grades to brown with slightly coarser overall
gradation S-5
............... ...............
............ ...................-.. ..............
------- -----------......................... ....... ......
------------
Grades to medium dense,saturated.brown.
....... .................. .................. ............... .......
gravelly,fine to coarse SAND with trace silt
30 -
(confinued) 0 20 40 so so foo
LEGEND MOISTURE CONTENT
2.Minch OD split-sp000 sarnple PH 0 Soil pH test Plastic Unlit Natural Liquid Unlit
A&
Ckoundw�lewl a tirm of driffing -%VAI Rcnstmtyte�t YET AG R A
ATD Earth & Environmental
11336 NE Mnd Way,Sutte 100
WE No Votodwater encountered Grain sill analysis KWdand,Wast*Von 98034-&18
Drilling method: HSA Hamma type: Autornafic Date draied: 25 September 1995 Logged by: SWG
PROJECT: Renton Retail Site wo. 77-70527-00 BORINGNO. B- 79
SOIL DESCRIPTION PENETRATION RESISTANCE Page 2
Location; Cat Road, West part of Site A of 2
Standard Blows per foot Other
Approximate ground surface elevation: Unknown G 10 20 30 40 60
30 SAND(As Above)
S-6
. ................ ....
........... ------- ............. ...................... ........
...................... .............-
—------------------------------- ....... ............... ..............
Dense,saturated,brown,flne to coarse,sandy
-35 GRAVEL with some silt
S-7
Boring terminated at oppro)dmotely ......
36.5 feet ....... ....... ....... ...... ....................... ...............
............ ....... ...................... ............. ----------
-40
... .............. ...................... ------- -------
L------- -------4..............i ........... ....... ---------------
--------------- -------- ......................... ....... ................ . - ----------....................... ....... ....... ......
- 45
....... ------- -------------- ............... ....... ...............
....... ----------........................... ....... -------
-4....... ............... ------- ...............
....... ............................................. .............
- 50
...... ------- .............. ....................... .............. ....-
....... ............... ......................
-4------ j............... .....................-
....... ....... ....... ....... ...... ....... ................--------
- 55
........... ......................-............. ....... ---------------
.......... ........... ......... ...... ...............
............... ---------------.... . .......
4..... ...... ---------------............... ...............--------
160 20 40 60 80 100
6 LEGEND MOISTURE CONTENT
Plasticlifnit Natural liaudlirniL
2 2.Whnch OD split-spoon sample P/b70 Sod PH test
W
'e An) Resistivity test A G R A
'VF Groundwaterlevei aLinicof drilling Earth & Environmental
NIE No groundwater c�rcd Grain au analysis 11335 NE 122nd Way,Suite 100
KIrldand,Washington 98034-6918
Drilling method: HSA Hatuffner type; Automatic Dale drilled: 25 September 1995 Logged by: BWG
n
X
J
I
APPENDIX B
LABORATORY TESTING PROCEDURES AND RESULTS
APPENDIX B
1 1-1 0 521-00
Laboratory Testing Procedures
A series of laboratory tests were performed during the course of this study to evaluate the
index and geotechnical engineering properties of the subsurface soils.
Visual Classification
Samples recovered from the exploration locations were visually classified in the field during
the exploration program. Representative portions of the samples were carefully packaged in
watertight containers and transported to our laboratory where the field classifications were
verified or modified as required. Visual classification was done in general accordance with the
Unified Soil Classification system. Visual soil classification includes color, relative moisture
content, soil type based on grain size, and accessory soil types included in the sample.
Moisture Content Determinations
Moisture content determinations were performed on representative samples obtained from the
explorations in order to aid in identification and correlation of soil types. The determinations
were made in general accordance with the test procedures described in ASTM:D 2216. The
results of the tests are shown on the exploration logs in Appendix A.
Grain Size Analysis
A grain size analysis indicates the range of soil grain sizes included in a particular sample
based on particle diameter. Grain size analyses were performed on representative samples in
general accordance with ASTM:D 422. The results of the grain size determinations are
presented in this appendix.
California Bearing Ratio Tests
A California Bearing Ratio test was performed on a composite sample of the site soils in
general accordance with ASTM:D 1883-73, to provided an evaluation of the relative quality
and support characteristics of subgrade soils. Representative portions from the sample were
compacted in a mold, in general accordance with ASTM:D 1557-78 to provided a moisture-
density relationship curve. Following compaction, a 15-pound surcharge was applied to each
sample which was then totally immersed in water and allowed to soak for a period of 72 to
96 hours, during which time it was monitored for swell. At the end of this period the sample
was removed, drained and a vertical load applied to the surcharged soil with a penetration
piston at a constant rate of strain. Measurements of the applied vertical load were obtained
at selected penetration depths. CBR test results and moisture-density relationships plotted
in terms of percent water content versus percent corrected CBR and dry density are presented
in this appendix.
Soil Chemical Analytical Tests
For use in determining corrosion potential of the site soils, we submitted soil samples for pH
and resistivity tests. Samples were submitted to Am Test in Redmond, Washington. Samples
from borings were submitted for pH testing while samples from borings were submitted for
resistivity testing. The results are presented at the end of Appendix B.
I
SOIL CHEMICAL ANALYSIS RESULTS
SAMPLE LOCATION pH Resistivity (ohm-
B-7, S-1 6.5 10,000
B-19, S-1 6.3 6,400
GRAIN SIZE DISTRIBUTION
SIZE OF OPENING IN INCHES U.S. STANDARD SIEVE SIZE HYDROMETER
36- 12' 6' 3" 1 1/2' 3/4' 3/8" 4 10 20 40 60 100 200
100
so
80
2 70
WZU
J 60
m
W 50
Z
LL
Z 40
W
U
K
CL 30
a
20
10
0
1000.00 100.00 10.00 1.00 0.10 0.01 0.00
GRAIN SIZE IN MILLIMETERS
Coarse Fine Coarse I Medium Fine Sift Clay
FINEGMNED
Exploration Sample Depth Moisture Fines Soil Description
B-2 S-1 5.0-6.51 3% 3% Sandy GRAVEL,trace silt
•+-•-•-• B-14 S-1 5.0t.5' 18% 87% Fine Sandy SILT
•--1"--l"--'�- B-19 S-2 10.0-11.5' 32% 35% Silty Fine SAND
Project Renton Retail Site OAGRA
Work Order. 11-10521-00 Earth & Environmental
Date: 10-&95 11335 NE 122nd Way
Suite 100
Kirkland, Washington 98034-6918
CALIFORNIA BEARING RATIO (ASTM 1883)
125
124
123
(�)) 122
a 121
'y 120
G
N
Q 119
0 118
117
116
115
5 6 7 8 9 10 11 12 13 14 15
Moisture (% of Dry Weight)
100
90
6o
70
60
a 50
m
U 40
30
20
10
0
5 6 7 8 9 10 11 12 13 14 15
Moisture (016 of Dry Weight)
Project Renton Retail Site
Work order: 11-10521-00 IVAG RA
Date: 10-9-95 Earth B Environmental
Exploration: B-1 Sample: Grab 11335 NE 122nd Way
Max Density: 121.5 pcf Optimum Moisture: 10.5% Suite 100
USCS: Silty Gravelly SAND Kirkland, Washington 98034-6918
U
x
v
c
q�.
6
APPENDIX C
AASHTO PAVEMENT DESIGN
AASHTO 1986 METHOD FOR DESIGN OF PAVEMENT STRUCTURES
FOR: Proposed Retail Project - Renton, WA
DESIGN LIFE: 20 years
DESIGN CALIFORNIA BEARING RATIO: 5%
INPUT VALUES FOR STRUCTURAL NUMBER (SN) REFERENCE
Estimated ESAL (20 yrs) = 51,100 Specified
Reliability (R) = 85% Specified
Standard Normal Deviate (Z,) - = 1 ,037 1-62
Overall Standard Deviation (So) = 0.5 1-62, III-51
Roadbed Modulus (MR) = 7500 psi 1-14
Effective Resilient Modulus (MR, seasonally adjusted) = 4500 psi II-14
Initial Serviceability (Po) = 4.2 11-1 2
Terminal Serviceability (P) = 2.0 Specified
Design Serviceability Loss (PSI) = 2.2 II-12
Structural Number = 2.6 11-35
Input values for thickness calculations
Asphalt layer coefficient (a,) = 0.33 II-19
Base course layer coefficient (az) = 0.12 11-20
Base course drainage coefficient (m2) = 1 .15 II-26
Recommended Pavement Section Thicknesses (inches)
Asphalt Concrete Crushed Base Compacted Granular
Course Pit-run Subbase
Standard 2 4 6
Heavy 3 4 8
0
x
C
d
a
. f
APPENDIX D
FOUNDATION DESIGN CRITERIA AND GEOTECHNICAL INVESTIGATION FACT SHEET
J6
GEOTECHNICAL INVESTIGATION FACT SHEET
This form shall be included in the Geotechnical Investigation Report as an Appendix.
PROJECT: Proposed Retail Store LOCATION: Renton WA
(City) (State)
Geotechnical Investigation Report submitted By: AGRA Earth and Environmental. Inc.
i
SCS Soil Hydrologic Group Not Rated Soil Name Urban Land
Infiltration (Circle One): Poor Fair Good Very Good (not tested)
Ground Water Level:_6 feet Wet Season" 7'h - 14 feet Dry Season
Topsoil/Stripping Depth varies. 6 - 10 inches Undercut Required (Circle One): Ye No
Compaction Method (Circle one): Standard Proctor Modified Proctor
Minimum Compaction Required for Upper 1 Feet of Site:
Building Area 92 % Outlot Area 92 %
Parking Area 92 % Waste Area% 92 %
Compaction Equipment Type and Weight: Vibratory Roller
Compaction Tests: 1 Test for Each 5000 Sq. Ft. each Lift
Structural Fill Maximum Lift Thickness 8 inches (Measured loose)
Subgrade design CBR (or LBR) value = 5
COMPONENT ASPHALT CONCRETE
STANDARD HEAVY STANDARD HEAVY
Stabilized Subgrade
(If Applicable) (HRT) NA NA NA NA
Subbase Material
(Pit-run or Recycled 6 8 6 8
Concrete)
Asphaltic Base Course NA NA NA NA
(If Applicable)
Crushed Base/Top Course 4 4 4 4
(If Applicable)
— 2 _ 3_ 5 _6
Surface Course
II
Note: This information should not be used separately from other portions of this Soil
Investigation Report.
FOUNDATION DESIGN CRITERIA
This form shall be included in the Geotechnical Investigation Report as an Appendix
PROJECT:_ Proposed Retail Store
LOCATION: Renton, WA
City) (State)
GEOTECHNICAL ENGINEER: AGRA Earth and Environmental. Inc.
SOILS REPORT DATED: 11 October 1995
Recommended
Option
FOUNDATION OPTIONS:
1 Auaercast Foundation Piles
2
3
BEARING PRESSURE: Dependent on pile diameter and length, see text
MINIMUM FOOTING SIZES: 18" continuous, 24" spread
MIN. FOOTING EMBEDMENT: 18 inches
FROST DEPTH: 18 inches
TOTAL SETTLEMENT (1 " MAX): 1/2 inch on piling
DIFFERENTIAL SETTLEMENT (1/2" MAX): 1/2 inch
SLAB: POTENTIAL VERTICAL RISE 0/2" MAX): none
VAPOR BARRIER: No (see rai)ort)
CAPILLARY BARRIER: 6 inches sand/gravel WSDOT Specs 9-03.12W, 13, 15, 16
SUBGRADE REACTION MODULUS: 150 pci
PERIMETER DRAINS REO'D:_Yes. See report text
I CONCRETE: X Type I X Type II — Type III _ Other
SPECIAL COMMENTS:
NOTE: This information should not be used separately from other portions of this soil
investigation report.
l