HomeMy WebLinkAboutEx_12_RS_Geotech_Report_210804_v1EarthSolutionsNWLLC
EarthSolutions
NW LLC
15365 N.E.90th Street,Suite 100 Redmond,WA 98052
(425)449-4704 Fax (425)449-4711
www.earthsolutionsnw.com
Geotechnical Engineering
Construction Observation/Testing
Environmental Services
GEOTECHNICAL ENGINEERING STUDY
HARRINGTON REDEVELOPMENT
960 HARRINGTON AVENUE NORTHEAST
RENTON,WASHINGTON
ES-7282
EXHIBIT 12
RECEIVED
08/30/2021 jding
PLANNING DIVISION
DocuSign Envelope ID: 9A2B0C09-72D8-490B-A60E-EAD24B2FAACB
PREPARED FOR
ZARNOOR ASSOCIATES, LLC
c/o MR. KARIM KARMALI
May 24, 2021
_________________________
Chase G. Halsen, L.G.
Project Geologist
_________________________
Keven D. Hoffmann, P.E.
Geotechnical Engineering Services Manager
GEOTECHNICAL ENGINEERING STUDY
HARRINGTON REDEVELOPMENT
960 HARRINGTON AVENUE NORTHEAST
RENTON, WASHINGTON
ES-7282
Earth Solutions NW, LLC
15365 Northeast 90th Street, Suite 100
Redmond, Washington 98052
Phone: 425-449-4704 | Fax: 425-449-4711
www.earthsolutionsnw.com
05/24/2021
05/24/2021
DocuSign Envelope ID: 9A2B0C09-72D8-490B-A60E-EAD24B2FAACB
Geotechnical-Engineering Report
Important Information about This
Subsurface problems are a principal cause of construction delays, cost overruns, claims, and disputes.
While you cannot eliminate all such risks, you can manage them. The following information is provided to help.
The Geoprofessional Business Association (GBA)
has prepared this advisory to help you – assumedly
a client representative – interpret and apply this
geotechnical-engineering report as effectively as
possible. In that way, you can benefit from a lowered
exposure to problems associated with subsurface
conditions at project sites and development of
them that, for decades, have been a principal cause
of construction delays, cost overruns, claims,
and disputes. If you have questions or want more
information about any of the issues discussed herein,
contact your GBA-member geotechnical engineer.
Active engagement in GBA exposes geotechnical
engineers to a wide array of risk-confrontation
techniques that can be of genuine benefit for
everyone involved with a construction project.
Understand the Geotechnical-Engineering Services
Provided for this Report
Geotechnical-engineering services typically include the planning,
collection, interpretation, and analysis of exploratory data from
widely spaced borings and/or test pits. Field data are combined
with results from laboratory tests of soil and rock samples obtained
from field exploration (if applicable), observations made during site
reconnaissance, and historical information to form one or more models
of the expected subsurface conditions beneath the site. Local geology
and alterations of the site surface and subsurface by previous and
proposed construction are also important considerations. Geotechnical
engineers apply their engineering training, experience, and judgment
to adapt the requirements of the prospective project to the subsurface
model(s). Estimates are made of the subsurface conditions that
will likely be exposed during construction as well as the expected
performance of foundations and other structures being planned and/or
affected by construction activities.
The culmination of these geotechnical-engineering services is typically a
geotechnical-engineering report providing the data obtained, a discussion
of the subsurface model(s), the engineering and geologic engineering
assessments and analyses made, and the recommendations developed
to satisfy the given requirements of the project. These reports may be
titled investigations, explorations, studies, assessments, or evaluations.
Regardless of the title used, the geotechnical-engineering report is an
engineering interpretation of the subsurface conditions within the context
of the project and does not represent a close examination, systematic
inquiry, or thorough investigation of all site and subsurface conditions.
Geotechnical-Engineering Services are Performed
for Specific Purposes, Persons, and Projects,
and At Specific Times
Geotechnical engineers structure their services to meet the specific
needs, goals, and risk management preferences of their clients. A
geotechnical-engineering study conducted for a given civil engineer
will not likely meet the needs of a civil-works constructor or even a
different civil engineer. Because each geotechnical-engineering study
is unique, each geotechnical-engineering report is unique, prepared
solely for the client.
Likewise, geotechnical-engineering services are performed for a specific
project and purpose. For example, it is unlikely that a geotechnical-
engineering study for a refrigerated warehouse will be the same as
one prepared for a parking garage; and a few borings drilled during
a preliminary study to evaluate site feasibility will not be adequate to
develop geotechnical design recommendations for the project.
Do not rely on this report if your geotechnical engineer prepared it:
• for a different client;
• for a different project or purpose;
• for a different site (that may or may not include all or a portion of
the original site); or
• before important events occurred at the site or adjacent to it;
e.g., man-made events like construction or environmental
remediation, or natural events like floods, droughts, earthquakes,
or groundwater fluctuations.
Note, too, the reliability of a geotechnical-engineering report can
be affected by the passage of time, because of factors like changed
subsurface conditions; new or modified codes, standards, or
regulations; or new techniques or tools. If you are the least bit uncertain
about the continued reliability of this report, contact your geotechnical
engineer before applying the recommendations in it. A minor amount
of additional testing or analysis after the passage of time – if any is
required at all – could prevent major problems.
Read this Report in Full
Costly problems have occurred because those relying on a geotechnical-
engineering report did not read the report in its entirety. Do not rely on
an executive summary. Do not read selective elements only. Read and
refer to the report in full.
You Need to Inform Your Geotechnical Engineer
About Change
Your geotechnical engineer considered unique, project-specific factors
when developing the scope of study behind this report and developing
the confirmation-dependent recommendations the report conveys.
Typical changes that could erode the reliability of this report include
those that affect:
• the site’s size or shape;
• the elevation, configuration, location, orientation,
function or weight of the proposed structure and
the desired performance criteria;
• the composition of the design team; or
• project ownership.
As a general rule, always inform your geotechnical engineer of project
or site changes – even minor ones – and request an assessment of their
impact. The geotechnical engineer who prepared this report cannot accept
DocuSign Envelope ID: 9A2B0C09-72D8-490B-A60E-EAD24B2FAACB
responsibility or liability for problems that arise because the geotechnical
engineer was not informed about developments the engineer otherwise
would have considered.
Most of the “Findings” Related in This Report
Are Professional Opinions
Before construction begins, geotechnical engineers explore a site’s
subsurface using various sampling and testing procedures. Geotechnical
engineers can observe actual subsurface conditions only at those specific
locations where sampling and testing is performed. The data derived from
that sampling and testing were reviewed by your geotechnical engineer,
who then applied professional judgement to form opinions about
subsurface conditions throughout the site. Actual sitewide-subsurface
conditions may differ – maybe significantly – from those indicated in
this report. Confront that risk by retaining your geotechnical engineer
to serve on the design team through project completion to obtain
informed guidance quickly, whenever needed.
This Report’s Recommendations Are
Confirmation-Dependent
The recommendations included in this report – including any options or
alternatives – are confirmation-dependent. In other words, they are not
final, because the geotechnical engineer who developed them relied heavily
on judgement and opinion to do so. Your geotechnical engineer can finalize
the recommendations only after observing actual subsurface conditions
exposed during construction. If through observation your geotechnical
engineer confirms that the conditions assumed to exist actually do exist,
the recommendations can be relied upon, assuming no other changes have
occurred. The geotechnical engineer who prepared this report cannot assume
responsibility or liability for confirmation-dependent recommendations if you
fail to retain that engineer to perform construction observation.
This Report Could Be Misinterpreted
Other design professionals’ misinterpretation of geotechnical-
engineering reports has resulted in costly problems. Confront that risk
by having your geotechnical engineer serve as a continuing member of
the design team, to:
• confer with other design-team members;
• help develop specifications;
• review pertinent elements of other design professionals’ plans and
specifications; and
• be available whenever geotechnical-engineering guidance is needed.
You should also confront the risk of constructors misinterpreting this
report. Do so by retaining your geotechnical engineer to participate in
prebid and preconstruction conferences and to perform construction-
phase observations.
Give Constructors a Complete Report and Guidance
Some owners and design professionals mistakenly believe they can shift
unanticipated-subsurface-conditions liability to constructors by limiting
the information they provide for bid preparation. To help prevent
the costly, contentious problems this practice has caused, include the
complete geotechnical-engineering report, along with any attachments
or appendices, with your contract documents, but be certain to note
conspicuously that you’ve included the material for information purposes
only. To avoid misunderstanding, you may also want to note that
“informational purposes” means constructors have no right to rely on
the interpretations, opinions, conclusions, or recommendations in the
report. Be certain that constructors know they may learn about specific
project requirements, including options selected from the report, only
from the design drawings and specifications. Remind constructors
that they may perform their own studies if they want to, and be sure to
allow enough time to permit them to do so. Only then might you be in
a position to give constructors the information available to you, while
requiring them to at least share some of the financial responsibilities
stemming from unanticipated conditions. Conducting prebid and
preconstruction conferences can also be valuable in this respect.
Read Responsibility Provisions Closely
Some client representatives, design professionals, and constructors do
not realize that geotechnical engineering is far less exact than other
engineering disciplines. This happens in part because soil and rock on
project sites are typically heterogeneous and not manufactured materials
with well-defined engineering properties like steel and concrete. That
lack of understanding has nurtured unrealistic expectations that have
resulted in disappointments, delays, cost overruns, claims, and disputes.
To confront that risk, geotechnical engineers commonly include
explanatory provisions in their reports. Sometimes labeled “limitations,”
many of these provisions indicate where geotechnical engineers’
responsibilities begin and end, to help others recognize their own
responsibilities and risks. Read these provisions closely. Ask questions.
Your geotechnical engineer should respond fully and frankly.
Geoenvironmental Concerns Are Not Covered
The personnel, equipment, and techniques used to perform an
environmental study – e.g., a “phase-one” or “phase-two” environmental
site assessment – differ significantly from those used to perform a
geotechnical-engineering study. For that reason, a geotechnical-engineering
report does not usually provide environmental findings, conclusions, or
recommendations; e.g., about the likelihood of encountering underground
storage tanks or regulated contaminants. Unanticipated subsurface
environmental problems have led to project failures. If you have not
obtained your own environmental information about the project site,
ask your geotechnical consultant for a recommendation on how to find
environmental risk-management guidance.
Obtain Professional Assistance to Deal with
Moisture Infiltration and Mold
While your geotechnical engineer may have addressed groundwater,
water infiltration, or similar issues in this report, the engineer’s
services were not designed, conducted, or intended to prevent
migration of moisture – including water vapor – from the soil
through building slabs and walls and into the building interior, where
it can cause mold growth and material-performance deficiencies.
Accordingly, proper implementation of the geotechnical engineer’s
recommendations will not of itself be sufficient to prevent
moisture infiltration. Confront the risk of moisture infiltration by
including building-envelope or mold specialists on the design team.
Geotechnical engineers are not building-envelope or mold specialists.
Copyright 2019 by Geoprofessional Business Association (GBA). Duplication, reproduction, or copying of this document, in whole or in part, by any means whatsoever, is strictly
prohibited, except with GBA’s specific written permission. Excerpting, quoting, or otherwise extracting wording from this document is permitted only with the express written permission of
GBA, and only for purposes of scholarly research or book review. Only members of GBA may use this document or its wording as a complement to or as an element of a report of any kind.
Any other firm, individual, or other entity that so uses this document without being a GBA member could be committing negligent or intentional (fraudulent) misrepresentation.
Telephone: 301/565-2733
e-mail: info@geoprofessional.org www.geoprofessional.org
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May 24, 2021
ES-7282
Zarnoor Associates, LLC
c/o Mr. Karim Karmali
19515 North Creek Parkway, Suite 314
Bothell, Washington 98011
Attention: Mr. Nazim Karmali
Dear Mr. Karmali:
Earth Solutions NW, LLC (ESNW) is pleased to present this geotechnical report to support the
design and construction of the proposed mixed-use development, currently known as the
Harrington Redevelopment. Based on the results of our investigation, the proposed
redevelopment is feasible from a geotechnical standpoint. Our study indicates the site is
underlain primarily by dense to very dense glacial till.
Based on our findings, the proposed mixed-use structure may be constructed on a conventional
continuous and spread footing foundations bearing upon competent native soil, recompacted
native soil, or new structural fill placed directly on competent native soil. Competent native soil
suitable for support of the proposed building will likely be encountered beginning at depths of
about two-and-one-half to five feet below existing grades across most of the site. Soil in the
northwest site corner was characterized as loose to medium dense during the field exploration;
accordingly, areas of native soil may need to be either mechanically recompacted or
overexcavated and replaced with suitable structural fill to establish competent and uniform soil
bearing conditions. In general, where loose or unsuitable soil conditions are exposed at
foundation subgrade elevations, compaction of the soil to the specifications of structural fill or
overexcavation and replacement with suitable structural fill will be necessary.
Full infiltration is not recommended from a geotechnical standpoint given the predominance of
dense silty sand encountered across most of the site. Sandier soils encountered near the
northwest site corner may prove feasible for limited, targeted infiltration. However, any design
would need to incorporate provisions for overflow. If infiltration is pursued, ESNW should be
contacted to provide supplementary consulting and testing services.
Pertinent geotechnical recommendations are provided in this study. We appreciate the
opportunity to be of service to you on this project. If you have any questions regarding the content
of this geotechnical engineering study, please call.
Sincerely,
EARTH SOLUTIONS NW, LLC
Chase G. Halsen, L.G.
Project Geologist
15365 N.E. 90th Street, Suite 100 • Redmond, WA 98052 •(425) 449-4704 • FAX (425) 449-4711
Earth Solutions NW LLC
Geotechnical Engineering, Construction
Observation/Testing and Environmental Services
DocuSign Envelope ID: 9A2B0C09-72D8-490B-A60E-EAD24B2FAACB
Earth Solutions NW, LLC
Table of Contents
ES-7282
PAGE
INTRODUCTION ................................................................................. 1
General..................................................................................... 1
Project Description ................................................................. 2
SITE CONDITIONS ............................................................................. 2
Surface ..................................................................................... 2
Subsurface .............................................................................. 2
Topsoil and Fill ............................................................. 3
Native Soil ..................................................................... 3
Geologic Setting ........................................................... 3
Groundwater ................................................................. 3
Critical Areas Review ............................................................. 4
DISCUSSION AND RECOMMENDATIONS ....................................... 4
General..................................................................................... 4
Site Preparation and Earthwork ............................................. 4
Temporary Erosion Control ......................................... 4
Excavations and Slopes .............................................. 5
In-situ and Imported Soil ............................................. 5
Subgrade Preparation .................................................. 6
Wet Season Grading…………………………………...... 6
Structural Fill ................................................................ 6
Foundations ............................................................................ 7
Seismic Design ....................................................................... 8
Slab-on-Grade Floors ............................................................. 9
Retaining Walls ....................................................................... 9
Drainage................................................................................... 10
Preliminary Infiltration Feasibility ............................... 10
Utility Support and Trench Backfill ....................................... 10
LIMITATIONS ...................................................................................... 11
Additional Services ................................................................. 11
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Earth Solutions NW, LLC
Table of Contents
Cont’d
ES-7282
GRAPHICS
Plate 1 Vicinity Map
Plate 2 Boring Location Plan
Plate 3 Retaining Wall Drainage Detail
Plate 4 Footing Drain Detail
APPENDICES
Appendix A Subsurface Exploration
Boring Logs
Appendix B Laboratory Test Results
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Earth Solutions NW, LLC
GEOTECHNICAL ENGINEERING STUDY
HARRINGTON REDEVELOPMENT
960 HARRINGTON AVENUE NORTHEAST
RENTON, WASHINGTON
ES-7282
INTRODUCTION
General
This geotechnical engineering study (study) was prepared for the proposed mixed-use project
(currently referred to as the Harrington Redevelopment), to be constructed directly southeast of
the intersection between Northeast Sunset Boulevard and Harrington Avenue Northeast, in
Renton, Washington. This study was prepared to provide geotechnical recommendations for
currently proposed development plans and included the following geotechnical services:
Borings to characterize soil and groundwater conditions.
Laboratory testing of representative soil samples collected at the boring locations.
Engineering analyses.
The following documents and maps were reviewed as part of our study preparation:
Feasibility Study for Revised Options – Surface Parking, prepared by Grouparchitect,
dated August 10, 2020.
Conceptual Site Plan for 25% Schematic Design, prepared by Grouparchitect, dated
February 4, 2021.
ALTA/NSPS Land Title Survey, prepared by Axis Survey & Mapping, Inc., dated January
7, 2020.
Online Web Soil Survey (WSS) resource, maintained by the Natural Resources
Conservation Service (NRCS) under the United States Department of Agriculture (USDA).
Geologic Map of the Renton Quadrangle, Washington, prepared by D.R. Mullineaux, 1965.
Chapter 3, Title IV of the Renton Municipal Code.
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Project Description
We understand the project is pursing construction of a six-story, mixed-use structure and
associated site improvements. The at-grade level will include a parking garage, retail space, and
residential accessories, and levels two through six will be apartments. Site ingress and egress
will be provided by Northeast Sunset Boulevard.
At the time of report submission, specific building load plans were not available for review. Based
on our experience with similar developments, the proposed structure will utilize a concrete
podium for at-grade level construction, with lightly loaded wood farming above. Perimeter footing
loads will likely be about 5 to 6 kips per lineal foot. Slab-on-grade loading is anticipated to be
approximately 150 pounds per square foot (psf). We anticipate grade modifications (cuts or fills)
of less than five feet will be necessary to establish design elevations.
If the above design assumptions either change or are incorrect, ESNW should be contacted to
review the recommendations provided in this report. ESNW should review final designs to
confirm that appropriate geotechnical recommendations have been incorporated into the plans.
SITE CONDITIONS
Surface
The subject site is located at the southeast corner of the Northeast Sunset Boulevard and
Harrington Avenue Northeast intersection, in Renton, Washington. The approximate site location
is depicted on Plate 1 (Vicinity Map). The irregularly shaped site consists of King County Parcel
No. 722780-1025, totaling about 0.67 acres.
The site is bordered to the north by Northeast Sunset Boulevard, to the east by a Safeway grocery
store and parking lot, to the south by an apartment building, and to the west by Harrington Avenue
Northeast. The existing topography descends to the southwest, with about six to eight feet of
elevation change across the subject site. The site is currently developed with two restaurants
(Subway and Pizza Hut) and associated improvements. Most of the site is surfaced with asphalt.
Subsurface
An ESNW representative observed, logged, and sampled the advancement of three soil borings
on February 12, 2021. The borings were completed within accessible areas of the property using
a drill rig and operators retained by our firm. The approximate locations of the borings are
depicted on Plate 2 (Boring Location Plan). Please refer to the boring logs provided in Appendix
A for a more detailed description of subsurface conditions. Representative soil samples collected
at the boring locations were analyzed in general accordance with both Unified Soil Classification
System (USCS) and USDA methods and procedures.
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Topsoil and Fill
Topsoil was not encountered at the boring locations. Given the existing level of development,
significant amount of topsoil is not expected across the site.
Silty sand fill was encountered at B-2, extending to a depth of about four-and-one-half feet below
the existing ground surface (bgs). The fill was characterized as very loose and moist. As stated
above, asphalt covers most of the ground surface across the site. Asphalt thicknesses were
about one to two inches at the boring locations.
Native Soil
Native site soil encountered at the boring locations consisted primarily of silty sand (USCS: SM).
Localized areas of poorly graded sand with silt and well-graded sand with silt (USCS: SP-SM and
SW-SM) were encountered at B-3. Native soils were primarily observed in a medium dense to
very dense and moist condition and generally exhibited an increasingly dense condition with
depth. However, the approximate upper 10 feet of soil encountered at B-3 was characterized as
loose to medium dense. Each boring location was terminated in very dense native soil and
extended to a maximum exploration depth of about 26.5 feet bgs.
Geologic Setting
The referenced geologic map resource identifies ground moraine deposits (Qgt) as underlying
the site and adjacent areas. Ground moraine deposits, otherwise known as glacial till, are
considered an unsorted mixture of sand, silt, clay, and gravel. The referenced WSS resource
identifies soils of the Ragnar-Indianola association and Urban land designations across the site
and immediately adjacent areas. The Ragnar-Indianola associations is representative of kame,
terrace, and eskers landforms, while designations of Urban land suggest historic earthwork
activities and grade modifications in the area. Based on the encountered conditions, native soils
are generally considered representative of ground moraine (glacial till) deposits in accordance
with local geologic mapping.
Groundwater
Minor perched groundwater seepage was exposed at a depth of about 10 feet bgs within B-1.
Zones of perched groundwater seepage should be expected during general earthwork activities
and will likely develop within the soil substratum depending on the time of year. Seepage rates
and elevations fluctuate depending on many factors, including precipitation duration and intensity,
the time of year, and soil conditions. In general, groundwater flow rates are higher during the
winter, spring, and early summer months.
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Critical Areas Review
The City of Renton GIS mapping application and Chapter 3, Title IV of the Renton Municipal Code
were reviewed to evaluate the presence of jurisdictionally recognized geologic hazards on site or
on immediately adjacent parcels. Review of these applications did not indicate the presence of
any jurisdictionally recognized geologic hazards in the area. In addition, we did not observe any
obvious indication of the presence of these hazards at surface grades or within the boring
locations.
DISCUSSION AND RECOMMENDATIONS
General
Based on the results of our investigation, construction of the proposed residential development
is feasible from a geotechnical standpoint. The primary geotechnical considerations for the
proposal are in reference to structural fill placement and compaction, established a suitable
subgrade to support the proposed mixed-use structure, foundation design, and stormwater
management recommendations.
Site Preparation and Earthwork
Initial site preparation activities will consist of installing temporary erosion control measures,
establishing grading limits, and demolishing existing improvements. Subsequent earthwork
activities will involve site grading activities, foundation preparation, and installation of
infrastructure improvements.
Temporary Erosion Control
The following temporary erosion and sediment control (TESC) Best Management Practices
(BMPs) are offered:
Temporary construction entrances and drive lanes should be constructed with at least six
inches of quarry spalls to both minimize off-site soil tracking and provide a stable access
entrance surface. A woven geotextile fabric can be placed beneath the quarry spalls to
provide greater stability, if needed.
Silt fencing should be placed around the site perimeter.
When not in use, soil stockpiles should be covered or otherwise protected. Stockpiles
should never be placed at the top of slopes, whether the slopes are native or created
through grading.
Temporary measures for controlling surface water runoff, such as interceptor trenches,
sumps, or interceptor swales, should be installed prior to beginning earthwork activities.
Dry soils disturbed during construction should be wetted to reduce dust.
When appropriate, permanent planting or hydroseeding will help to stabilize site soils.
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Additional TESC BMPs, as specified by the project civil engineer and/or as indicated on the TESC
plans, should be incorporated into construction activities. TESC measures must be upkept and
may require modification during construction to ensure proper function.
Excavations and Slopes
Based on the soil conditions observed at the boring locations, the following allowable temporary
slope inclinations, as a function of horizontal to vertical (H:V) inclination, may be used. The
applicable Federal Occupation Safety and Health Administration (OSHA) and Washington
Industrial Safety and Health Act (WISHA) soil classifications are also provided:
Loose to medium dense soil 1.5H:1V (Type C)
Areas exposing groundwater seepage 1.5H:1V (Type C)
Dense to very dense, undisturbed native soil 0.75H:1V (Type A)
Steeper temporary slope inclinations within undisturbed, very dense native soil may be feasible
based on the soil and groundwater conditions exposed within the excavations. ESNW can
evaluate the feasibility of utilizing steeper temporary slopes at the time of construction, on a case-
by-case basis. In any event, an ESNW representative should observe temporary slopes to
confirm inclinations are suitable for the exposed soil conditions and to provide additional
excavation and slope stability recommendations, as necessary.
If the recommended temporary slope inclinations cannot be achieved, temporary shoring may be
necessary to support excavations. Permanent slopes should be graded to 2H:1V (or flatter) and
planted with vegetation to enhance stability and minimize erosion potential. Permanent slopes
should be observed by ESNW prior to vegetation and landscaping.
In-situ and Imported Soil
Successful use of the on-site soil as structural fill will largely be dictated by the moisture content
at the time of placement and compaction. Based on the conditions observed during our
subsurface exploration, the on-site soil is highly moisture sensitive. Depending on the time of
year construction occurs, remedial measures (such as soil aeration) may be necessary as part
of site grading and earthwork activities. If the on-site soil cannot be successfully compacted, the
use of an imported soil may be necessary.
In our opinion, a contingency should be provided in the project budget for export of soil that cannot
be successfully compacted as structural fill, particularly if grading activities take place during
periods of extended rainfall activity. In general, soils with fines contents greater than 5 percent
typically degrade rapidly when exposed to periods of rainfall.
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Imported structural fill soil should consist of a well-graded, granular soil that can achieve a
suitable working moisture content. During wet weather conditions, imported soil intended for use
as structural fill should consist of a well-graded, granular soil with a fines content of 5 percent or
less (where the fines content is defined as the percent passing the Number 200 sieve, based on
the minus three-quarter-inch fraction).
Subgrade Preparation
Foundation and slab subgrade surfaces should consist of competent, undisturbed native soil or
structural fill placed and compacted atop competent native soil. ESNW should observe subgrade
areas prior to placing formwork. Supplementary recommendations for subgrade improvement
may be provided at the time of construction; such recommendations would likely include further
mechanical compaction effort or overexcavation and replacement with suitable structural fill.
Wet Season Grading
Earthwork activities that occur during wet weather conditions may require additional measures to
protect structural subgrades and soils intended for use as structural fill. Site-specific
recommendations can be provided at the time of construction and may include leaving cut areas
several inches above design elevations, covering working surfaces with crushed rock, protecting
structural fill soils from adverse moisture conditions, and additional TESC recommendations.
ESNW can assist in obtaining a wet season grading permit or extension, where appropriate, if
required by the governing jurisdiction.
Structural Fill
Structural fill is defined as compacted soil placed in foundation, slab-on-grade, roadway,
permanent slope, retaining wall, and utility trench backfill areas. The following recommendations
are provided for soils intended for use as structural fill:
Moisture content At or slightly above optimum
Relative compaction (minimum) 95 percent (per ASTM D1557)
Loose lift thickness (maximum) 12 inches
Existing site soil may only be considered suitable for use as structural fill if it can achieve a
suitable moisture content at the time of placement and compaction. If the on-site soil cannot
meet the above specifications, use of an imported structural fill material will likely be necessary.
With respect to underground utility installations and backfill, local jurisdictions will likely dictate
soil type(s) and compaction requirements.
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Zarnoor Associates, LLC ES-7282
c/o Mr. Karim Karmali Page 7
May 24, 2021
Earth Solutions NW, LLC
Foundations
In our opinion, the proposed mixed-use structure may be constructed on a conventional
continuous and spread footing foundations bearing upon competent native soil, recompacted
native soil, or new structural fill placed directly on competent native soil. Competent native soil
suitable for support of the proposed building will likely be encountered beginning at depths of
about two-and-one-half to five feet bgs across most of the site. Soils encountered at B-3
(northwest corner) were characterized as loose to medium dense to a depth of about 10 feet bgs.
Loose native soil will likely need to be either mechanically recompacted or overexcavated and
replaced with suitable structural fill to establish competent and uniform soil bearing conditions.
ESNW should be on site during foundation preparation activities to further delineate areas
requiring remediation and provide additional recommendations. In general, where loose or
unsuitable soil conditions are exposed at foundation subgrade elevations, compaction of the soil
to the specifications of structural fill or overexcavation and replacement with suitable structural
fill will be necessary.
Provided the foundations will be supported as suggested, the following parameters may be used
for design:
Allowable soil bearing capacity 3,000 psf
Passive earth pressure 300 pcf (equivalent fluid)
Coefficient of friction 0.40
An allowable soil bearing capacity of 5,000 psf may be used for design only if foundation elements
are supported directly on either dense native soil or two-inch-diameter, clean crushed rock placed
directly on dense native soil. Common-earth fill is not considered suitable for use as structural
fill where a higher soil bearing capacity is desired. As such, if the higher soil bearing capacity is
assumed for design, overexcavation to dense native soil should be expected in some areas but
will ultimately depend on final grades and subgrade elevations.
The above passive pressure and friction values include a factor-of-safety (FOS) of 1.5. A one-
third increase in the allowable soil bearing capacity may be assumed for short-term wind and
seismic loading conditions. With structural loading as expected, total settlement in the range of
one inch and differential settlement of about one-half inch is anticipated. Most settlement should
occur during construction when dead loads are applied.
ESNW should be retained to evaluate foundation subgrade areas at the time of construction to
document suitable bearing conditions and provide additional recommendations, as deemed
necessary.
DocuSign Envelope ID: 9A2B0C09-72D8-490B-A60E-EAD24B2FAACB
Zarnoor Associates, LLC ES-7282
c/o Mr. Karim Karmali Page 8
May 24, 2021
Earth Solutions NW, LLC
Seismic Design
The 2018 International Building Code (2018 IBC) recognizes the most recent edition of the
Minimum Design Loads for Buildings and Other Structures manual (ASCE 7-16) for seismic
design, specifically with respect to earthquake loads. Based on the soil conditions encountered
at the boring locations, the parameters and values provided below are recommended for seismic
design per the 2018 IBC.
Parameter Value
Site Class C*
Mapped short period spectral response acceleration, S S (g) 1.428
Mapped 1-second period spectral response acceleration, S 1 (g) 0.488
Short period site coefficient, Fa 1.2
Long period site coefficient, Fv 1.5
Adjusted short period spectral response acceleration, S MS (g) 1.714
Adjusted 1-second period spectral response acceleration, S M1 (g) 0.732
Design short period spectral response acceleration, S DS (g) 1.142
Design 1-second period spectral response acceleration, S D1 (g) 0.488
* Assumes very dense soil conditions, encountered to a maximum depth of 26.5 feet bgs during the February 2021
field exploration, remain very dense to at least 100 feet bgs. Based on our experience with the project geologic
setting (glacial till) across the Puget Sound region, soil conditions are likely consistent with this assumption.
Further discussion between the project structural engineer, the project owner (or their
representative), and ESNW may be prudent to determine the possible impacts to the structural
design due to increased earthquake load requirements under the 2018 IBC. ESNW can provide
additional consulting services to aid with design efforts, including supplementary geotechnical
and geophysical investigation, upon request.
Liquefaction is a phenomenon where saturated or loose soil suddenly loses internal strength and
behaves as a fluid. This behavior is in response to increased pore water pressures resulting from
an earthquake or another intense ground shaking. In our opinion, site susceptibility to liquefaction
may be considered negligible. The absence of a shallow groundwater table and the relatively
dense characteristics of the native soil were the primary bases for this opinion.
DocuSign Envelope ID: 9A2B0C09-72D8-490B-A60E-EAD24B2FAACB
Zarnoor Associates, LLC ES-7282
c/o Mr. Karim Karmali Page 9
May 24, 2021
Earth Solutions NW, LLC
Slab-on-Grade Floors
Slab-on-grade floors for the proposed mixed-use structure should be supported on competent,
firm, and unyielding subgrades. Unstable or yielding subgrade areas should be recompacted or
overexcavated and replaced with suitable structural fill prior to slab construction. A capillary
break consisting of at least four inches of free-draining crushed rock or gravel should be placed
below each slab. The free-draining material should have a fines content of 5 percent or less
(where the fines content is defined as the percent passing the Number 200 sieve, based on the
minus three-quarter-inch fraction). In areas where slab moisture is undesirable, installation of a
vapor barrier below the slab should be considered. Vapor barriers should be made from material
specifically designed for use as a vapor barrier and should be installed in accordance with the
manufacturer’s recommendations.
Retaining Walls
Retaining walls must be designed to resist earth pressures and applicable surcharge loads. The
following parameters may be used for design:
Active earth pressure (unrestrained condition) 35 pcf (equivalent fluid)
At-rest earth pressure (restrained condition) 55 pcf
Traffic surcharge* (passenger vehicles) 70 psf (rectangular distribution)
Passive earth pressure 300 pcf (equivalent fluid)
Coefficient of friction 0.40
Seismic loading condition 8H psf**
* Where applicable
** Where H equals the retained height (in feet)
The above passive pressure and friction values include a FOS of 1.5 and are based on a level
backfill condition and level grade at the wall toe. Revised design values will be necessary if
sloping grades are to be used above or below retaining walls. Additional surcharge loading from
adjacent foundations, sloped backfill, or other relevant loads should be included in the retaining
wall design.
Retaining walls should be backfilled with free-draining material that extends along the height of
the wall and a distance of at least 18 inches behind the wall. The upper 12 inches of the wall
backfill may consist of a less permeable soil, if desired. A sheet drain may be considered in lieu
of free-draining backfill. A perforated drainpipe should be placed along the base of the wall and
connected to an approved discharge location. A typical retaining wall drainage detail is provided
on Plate 3. If drainage is not provided, hydrostatic pressures should be included in the wall
design.
DocuSign Envelope ID: 9A2B0C09-72D8-490B-A60E-EAD24B2FAACB
Zarnoor Associates, LLC ES-7282
c/o Mr. Karim Karmali Page 10
May 24, 2021
Earth Solutions NW, LLC
Drainage
Discrete zones of perched groundwater seepage should be anticipated in site excavations
depending on the time of year grading operations take place, particularly within deeper
excavations for utilities. Temporary measures to control surface water runoff and groundwater
during construction would likely involve interceptor trenches, interceptor swales, and sumps.
ESNW should be consulted during preliminary grading to both identify areas of seepage and
provide recommendations to reduce the potential for seepage-related instability.
Finish grades must be designed to direct surface drain water away from structures and slopes.
Water must not be allowed to pond adjacent to structures or slopes. In our opinion, foundation
drains should be installed along building perimeter footings. A typical foundation drain detail is
provided on Plate 4.
Preliminary Infiltration Feasibility
Full infiltration is not recommended from a geotechnical standpoint given the predominance of
dense silty sand encountered across most of the site. Sandier soils encountered near the
northwest site corner may prove feasible for limited, targeted infiltration. However, any design
would need to incorporate provisions for overflow. For feasibility and sizing considerations only,
a preliminary infiltration rate of 0.5 inches per hour may be considered for infiltration facilities
proposed near the northwest site corner.
If infiltration is pursued, ESNW should be contacted to provide supplementary consulting and
testing services. Additional services concerning infiltration feasibility would likely include in-situ
testing and soil suitability verification.
Utility Support and Trench Backfill
In our opinion, the native soil will generally be suitable for support of utilities. Remedial measures
may be necessary in some areas to provide support for utilities, such as overexcavation and
replacement with structural fill and/or placement of geotextile fabric. Groundwater seepage may
be encountered within utility excavations, and caving of trench walls may occur where
groundwater is encountered. Depending on the time of year and conditions encountered,
dewatering or temporary trench shoring may be necessary during utility excavation and
installation.
The on-site soil may only be suitable for use as structural backfill throughout the utility trench
excavations if the soil is at (or slightly above) the optimum moisture content at the time of
placement and compaction. Moisture conditioning of the soil may be necessary at some locations
prior to use as structural fill. Each section of the utility lines must be adequately supported in the
bedding material. Utility trench backfill should be placed and compacted to the structural fill
specifications previously detailed in this report or to the applicable specifications of the presiding
jurisdiction.
DocuSign Envelope ID: 9A2B0C09-72D8-490B-A60E-EAD24B2FAACB
Zarnoor Associates, LLC ES-7282
c/o Mr. Karim Karmali Page 11
May 24, 2021
Earth Solutions NW, LLC
LIMITATIONS
This study has been prepared for the exclusive use of Zarnoor Associates, LLC, and its
representatives. The recommendations and conclusions provided in this study are professional
opinions consistent with the level of care and skill that is typical of other members in the
profession currently practicing under similar conditions in this area. No warranty, express or
implied, is made. Variations in the soil and groundwater conditions observed at the boring
locations may exist and may not become evident until construction. ESNW should reevaluate
the conclusions provided in this study if variations are encountered.
Additional Services
ESNW should have an opportunity to review final project plans with respect to the geotechnical
recommendations provided in this report. ESNW should also be retained to provide testing and
consultation services during construction.
DocuSign Envelope ID: 9A2B0C09-72D8-490B-A60E-EAD24B2FAACB
Drwn.MRS
Checked CGH Date Mar.2021
Date 03/29/2021 Proj.No.7282
Plate 1
Earth Solutions NWLLC
Geotechnical Engineering,Construction
EarthSolutionsNWLLC
EarthSolutions
NW LLC Observation/Testing and Environmental Services
Vicinity Map
Harrington Redevelopment
Renton,Washington
NORTHReference:
King County,Washington
OpenStreetMap.org
NOTE:This plate may contain areas of color.ESNW cannot be
responsible for any subsequent misinterpretation of the information
resulting from black &white reproductions of this plate.
SITE
Renton
DocuSign Envelope ID: 9A2B0C09-72D8-490B-A60E-EAD24B2FAACB
Plate
Proj.No.
Date
Checked By
Drwn.ByEarthSolutionsNWLLCGeotechnicalEngineering,ConstructionObservation/TestingandEnvironmentalServicesEarthSolutionsNWLLCEarthSolutionsNWLLCMRS
CGH
03/29/2021
7282
2BoringLocationPlan HarringtonRedevelopmentRenton,WashingtonLEGEND
Approximate Location of
ESNW Test Pit,Proj.No.
ES-7282,Feb.2021
Subject Site
Existing Building
NORTH
0 2 0 4 0 8 0
Sc ale in Feet1"=4 0 '
NOTE:This plate may contain areas of color.ESNW cannot be
responsible for any subsequent misinterpretation of the information
resulting from black &white reproductions of this plate.
NOTE:The graphics shown on this plate are not intended for design
purposes or precise scale measurements,but only to illustrate the
approximate test locations relative to the approximate locations of
existing and /or proposed site features.The information illustrated
is largely based on data provided by the client at the time of our
study.ESNW cannot be responsible for subsequent design changes
or interpretation of the data by others.
B-1
B-1
B-2
B-3
N .E. SU N SET BOULEVARDHARRI
NGTON AVENUE S.E.
340
334
340
334
DocuSign Envelope ID: 9A2B0C09-72D8-490B-A60E-EAD24B2FAACB
Drwn.MRS
Checked CGH Date Mar.2021
Date 03/29/2021 Proj.No.7282
Plate 3
Earth Solutions NWLLCEarthSolutionsNWLLC
EarthSolutions
NW LLC Geotechnical Engineer ing,C onstr uction
Observation/Testing and Environmental Services
Retaining Wall Drainage Detail
Harrington Redevelopment
Renton,Washington
NOTES:
Free-draining Backfill should consist
of soil having less than 5 percent fines.
Percent passing No.4 sieve should be
25 to 75 percent.
Sheet Drain may be feasible in lieu
of Free-draining Backfill,per ESNW
recommendations.
Drain Pipe should consist of perforated,
rigid PVC Pipe surrounded with 1-inch
Drain Rock.
LEGEND:
Free-draining Structural Backfill
1-inch Drain Rock
18"Min.
Structural
Fill
Perforated Rigid Drain Pipe
(Surround in Drain Rock)
SCHEMATIC ONLY -NOT TO SCALE
NOT A CONSTRUCTION DRAWING
DocuSign Envelope ID: 9A2B0C09-72D8-490B-A60E-EAD24B2FAACB
Drwn.MRS
Checked CGH Date Mar.2021
Date 03/29/2021 Proj.No.7282
Plate 4
Earth Solutions NWLLC
Geotechnical Engineering,Construction
Observation/Testing and Environmental Services
EarthSolutionsNWLLC
EarthSolutions
NW LLC
Footing Drain Detail
Harrington Redevelopment
Renton,Washington
Slope
Perforated Rigid Drain Pipe
(Surround in Drain Rock)
18"Min.
NOTES:
Do NOT tie roof downspouts
to Footing Drain.
Surface Seal to consist of
12"of less permeable,suitable
soil.Slope away from building.
LEGEND:
Surface Seal:native soil or
other low-permeability material.
1-inch Drain Rock
SCHEMATIC ONLY -NOT TO SCALE
NOT A CONSTRUCTION DRAW ING
DocuSign Envelope ID: 9A2B0C09-72D8-490B-A60E-EAD24B2FAACB
Earth Solutions NW, LLC
Appendix A
Subsurface Exploration
Boring Logs
ES-7282
Subsurface conditions at the subject site were explored on February 12, 2021, by advancing
three borings using a drill rig and operators retained by our firm. The approximate locations of
the borings are illustrated on Plate 2 of this study. The boring logs are provided in this Appendix.
The borings were advanced to a maximum depth of approximately 26.5 feet bgs.
The final logs represent the interpretations of the field logs and the results of laboratory analyses.
The stratification lines on the logs represent the approximate boundaries between soil types. In
actuality, the transitions may be more gradual.
DocuSign Envelope ID: 9A2B0C09-72D8-490B-A60E-EAD24B2FAACB
GRAVEL
AND
GRAVELLY
SOILS
CLAYEY GRAVELS, GRAVEL - SAND -
CLAY MIXTURES
WELL-GRADED SANDS, GRAVELLY
SANDS, LITTLE OR NO FINES
POORLY-GRADED SANDS,
GRAVELLY SAND, LITTLE OR NO
FINES
SILTY SANDS, SAND - SILT
MIXTURES
CLAYEY SANDS, SAND - CLAY
MIXTURES
INORGANIC SILTS AND VERY FINE
SANDS, ROCK FLOUR, SILTY OR
CLAYEY FINE SANDS OR CLAYEY
SILTS WITH SLIGHT PLASTICITY
INORGANIC CLAYS OF LOW TO
MEDIUM PLASTICITY, GRAVELLY
CLAYS, SANDY CLAYS, SILTY CLAYS,
LEAN CLAYS
ORGANIC SILTS AND ORGANIC
SILTY CLAYS OF LOW PLASTICITY
INORGANIC SILTS, MICACEOUS OR
DIATOMACEOUS FINE SAND OR
SILTY SOILS
INORGANIC CLAYS OF HIGH
PLASTICITY
SILTS
AND
CLAYS
MORE THAN 50%
OF MATERIAL IS
LARGER THAN
NO. 200 SIEVE
SIZE
MORE THAN 50%
OF MATERIAL IS
SMALLER THAN
NO. 200 SIEVE
SIZE
MORE THAN 50%
OF COARSE
FRACTION
PASSING ON NO.
4 SIEVE
MORE THAN 50%
OF COARSE
FRACTION
RETAINED ON NO.
4 SIEVE
SOIL CLASSIFICATION CHART
(APPRECIABLE
AMOUNT OF FINES)
(APPRECIABLE
AMOUNT OF FINES)
(LITTLE OR NO FINES)
FINE
GRAINED
SOILS
SAND
AND
SANDY
SOILS
SILTS
AND
CLAYS
ORGANIC CLAYS OF MEDIUM TO
HIGH PLASTICITY, ORGANIC SILTS
PEAT, HUMUS, SWAMP SOILS WITH
HIGH ORGANIC CONTENTS
LETTERGRAPH
SYMBOLSMAJOR DIVISIONS
COARSE
GRAINED
SOILS
TYPICAL
DESCRIPTIONS
WELL-GRADED GRAVELS, GRAVEL -
SAND MIXTURES, LITTLE OR NO
FINES
POORLY-GRADED GRAVELS,
GRAVEL - SAND MIXTURES, LITTLE
OR NO FINES
SILTY GRAVELS, GRAVEL - SAND -
SILT MIXTURES
CLEAN
GRAVELS
GRAVELS WITH
FINES
CLEAN SANDS
(LITTLE OR NO FINES)
SANDS WITH
FINES
LIQUID LIMIT
LESS THAN 50
LIQUID LIMIT
GREATER THAN 50
HIGHLY ORGANIC SOILS
DUAL SYMBOLS are used to indicate borderline soil classifications.
The discussion in the text of this report is necessary for a proper understanding of the nature
of the material presented in the attached logs.
GW
GP
GM
GC
SW
SP
SM
SC
ML
CL
OL
MH
CH
OH
PT
Earth Solutions NW LLC
DocuSign Envelope ID: 9A2B0C09-72D8-490B-A60E-EAD24B2FAACB
316.0
SS
SS
SS
SS
SS
67
67
67
100
0
22-24-31
(55)
17-28-28
(56)
14-15-20
(35)
19-26-28
(54)
50/5"
MC = 9.3%
Fines = 23.9%
MC = 6.5%
MC = 13.2%
MC = 5.3%
MC = 8.4%
SM
20.0
Brown silty SAND, medium dense, moist
-becomes gray, very dense
[USDA Classification: slightly gravelly SAND]
-becomes dense
-minor perched groundwater seepage
-increased sand content
-becomes very dense
NOTES Surface Conditions: asphalt ~1.5" to 2"
GROUND ELEVATION 336 ft
LOGGED BY CGH
DRILLING METHOD HSA
HOLE SIZE
DRILLING CONTRACTOR Geologic Drill Partners GROUND WATER LEVELS:
CHECKED BY KDH
DATE STARTED 2/12/21 COMPLETED 2/12/21
AT TIME OF DRILLING ---
AT END OF DRILLING ---
AFTER DRILLING ---
(Continued Next Page)SAMPLE TYPENUMBERDEPTH(ft)0
5
10
15
20
PAGE 1 OF 2
BORING NUMBER B-1
PROJECT NUMBER ES-7282 PROJECT NAME Harrington Redevelopment
GENERAL BH / TP / WELL - 7282.GPJ - GINT STD US.GDT - 5/24/21Earth Solutions NW, LLC
15365 N.E. 90th Street, Suite 100
Redmond, Washington 98052
Telephone: 425-449-4704
Fax: 425-449-4711
RECOVERY %BLOWCOUNTS(N VALUE)TESTS
U.S.C.S.MATERIAL DESCRIPTION
GRAPHICLOGDocuSign Envelope ID: 9A2B0C09-72D8-490B-A60E-EAD24B2FAACB
315.5SS10050/6"MC = 9.0%SM 20.5 Gray silty SAND, very dense, moist
Boring terminated at 20.5 feet below existing grade. Groundwater
seepage encountered at 10.0 feet during drilling. Boring backfilled with
bentonite.SAMPLE TYPENUMBERDEPTH(ft)20
PAGE 2 OF 2
BORING NUMBER B-1
PROJECT NUMBER ES-7282 PROJECT NAME Harrington Redevelopment
GENERAL BH / TP / WELL - 7282.GPJ - GINT STD US.GDT - 5/24/21Earth Solutions NW, LLC
15365 N.E. 90th Street, Suite 100
Redmond, Washington 98052
Telephone: 425-449-4704
Fax: 425-449-4711
RECOVERY %BLOWCOUNTS(N VALUE)TESTS
U.S.C.S.MATERIAL DESCRIPTION
GRAPHICLOGDocuSign Envelope ID: 9A2B0C09-72D8-490B-A60E-EAD24B2FAACB
331.5
316.0
SS
SS
SS
SS
SS
100
100
100
100
50
1-1-1
(2)
4-14-19
(33)
50/5"
11-14-18
(32)
50/4"
MC = 14.2%
MC = 13.9%
Fines = 26.6%
MC = 8.7%
MC = 11.0%
MC = 10.7%
SM
SM
4.5
20.0
Brown silty SAND, very loose, moist (Fill)
-trace organic material
Brown silty SAND, loose, moist
[USDA Classification: slightly gravelly sandy LOAM]
-becomes gray, dense
-minor iron oxide staining
-becomes very dense
-becomes dense
-possible obstruction
-no recovery due to obstruction. Sample taken from spoils.
NOTES Surface Conditions: asphalt ~1"
GROUND ELEVATION 336 ft
LOGGED BY CGH
DRILLING METHOD HSA
HOLE SIZE
DRILLING CONTRACTOR Geologic Drill Partners GROUND WATER LEVELS:
CHECKED BY KDH
DATE STARTED 2/12/21 COMPLETED 2/12/21
AT TIME OF DRILLING ---
AT END OF DRILLING ---
AFTER DRILLING ---
(Continued Next Page)SAMPLE TYPENUMBERDEPTH(ft)0
5
10
15
20
PAGE 1 OF 2
BORING NUMBER B-2
PROJECT NUMBER ES-7282 PROJECT NAME Harrington Redevelopment
GENERAL BH / TP / WELL - 7282.GPJ - GINT STD US.GDT - 5/24/21Earth Solutions NW, LLC
15365 N.E. 90th Street, Suite 100
Redmond, Washington 98052
Telephone: 425-449-4704
Fax: 425-449-4711
RECOVERY %BLOWCOUNTS(N VALUE)TESTS
U.S.C.S.MATERIAL DESCRIPTION
GRAPHICLOGDocuSign Envelope ID: 9A2B0C09-72D8-490B-A60E-EAD24B2FAACB
SS 50/0"Boring terminated at 20.0 feet below existing grade. No groundwater
encountered during drilling. Boring backfilled with bentonite.SAMPLE TYPENUMBERDEPTH(ft)PAGE 2 OF 2
BORING NUMBER B-2
PROJECT NUMBER ES-7282 PROJECT NAME Harrington Redevelopment
GENERAL BH / TP / WELL - 7282.GPJ - GINT STD US.GDT - 5/24/21Earth Solutions NW, LLC
15365 N.E. 90th Street, Suite 100
Redmond, Washington 98052
Telephone: 425-449-4704
Fax: 425-449-4711
RECOVERY %BLOWCOUNTS(N VALUE)TESTS
U.S.C.S.MATERIAL DESCRIPTION
GRAPHICLOGDocuSign Envelope ID: 9A2B0C09-72D8-490B-A60E-EAD24B2FAACB
330.5
318.0
SS
SS
SS
SS
SS
67
67
67
100
55
5-5-6
(11)
4-4-6
(10)
5-3-2
(5)
2-3-13
(16)
13-50/5"
MC = 8.4%
MC = 6.8%
Fines = 9.5%
MC = 9.6%
MC = 11.0%
Fines = 29.9%
MC = 7.5%
SP-
SM
SM
7.5
20.0
Brown poorly graded SAND with silt and gravel, medium dense, moist
[USDA Classification: very gravelly loamy coarse SAND]
Brown silty SAND, loose, moist
[USDA Classification: gravelly fine sandy LOAM]
-becomes gray, medium dense
-becomes very dense
NOTES Surface Conditions: asphalt ~1"
GROUND ELEVATION 338 ft
LOGGED BY CGH
DRILLING METHOD HSA
HOLE SIZE
DRILLING CONTRACTOR Geologic Drill Partners GROUND WATER LEVELS:
CHECKED BY KDH
DATE STARTED 2/12/21 COMPLETED 2/12/21
AT TIME OF DRILLING ---
AT END OF DRILLING ---
AFTER DRILLING ---
(Continued Next Page)SAMPLE TYPENUMBERDEPTH(ft)0
5
10
15
20
PAGE 1 OF 2
BORING NUMBER B-3
PROJECT NUMBER ES-7282 PROJECT NAME Harrington Redevelopment
GENERAL BH / TP / WELL - 7282.GPJ - GINT STD US.GDT - 5/24/21Earth Solutions NW, LLC
15365 N.E. 90th Street, Suite 100
Redmond, Washington 98052
Telephone: 425-449-4704
Fax: 425-449-4711
RECOVERY %BLOWCOUNTS(N VALUE)TESTS
U.S.C.S.MATERIAL DESCRIPTION
GRAPHICLOGDocuSign Envelope ID: 9A2B0C09-72D8-490B-A60E-EAD24B2FAACB
317.0
311.5
SS
SS
100
100
25-30-38
(68)
26-26-42
(68)
MC = 7.4%
Fines = 10.3%
MC = 5.0%
SM
SW-
SM
21.0
26.5
Gray silty SAND, very dense, moist
[USDA Classification: slightly gravelly coarse SAND]
Gray well-graded SAND with silt, very dense, moist
-4" silty sand lens
Boring terminated at 26.5 feet below existing grade. No groundwater
encountered during drilling.
Boring backfilled with bentonite.SAMPLE TYPENUMBERDEPTH(ft)20
25
PAGE 2 OF 2
BORING NUMBER B-3
PROJECT NUMBER ES-7282 PROJECT NAME Harrington Redevelopment
GENERAL BH / TP / WELL - 7282.GPJ - GINT STD US.GDT - 5/24/21Earth Solutions NW, LLC
15365 N.E. 90th Street, Suite 100
Redmond, Washington 98052
Telephone: 425-449-4704
Fax: 425-449-4711
RECOVERY %BLOWCOUNTS(N VALUE)TESTS
U.S.C.S.MATERIAL DESCRIPTION
GRAPHICLOGDocuSign Envelope ID: 9A2B0C09-72D8-490B-A60E-EAD24B2FAACB
Earth Solutions NW, LLC
Appendix B
Laboratory Test Results
ES-7282
DocuSign Envelope ID: 9A2B0C09-72D8-490B-A60E-EAD24B2FAACB
0
5
10
15
20
25
30
35
40
45
50
55
60
65
70
75
80
85
90
95
100
0.0010.010.1110100
3
D100
140
Specimen Identification
1
fine
6
HYDROMETER
304
23.9
26.6
9.5
29.9
10.3
101/2
COBBLES
Specimen Identification
4
coarse
20 401.5 8 14
USDA: Gray Slightly Gravelly Loamy Sand. USCS: SM.
USDA: Gray Slightly Gravelly Sandy Loam. USCS: SM.
USDA: Brown Very Gravelly Loamy Coarse Sand. USCS: SP-SM with Gravel.
USDA: Gray Gravelly Fine Sandy Loam. USCS: SM.
USDA: Gray Slightly Gravelly Coarse Sand. USCS: SW-SM.
6 60
PERCENT FINER BY WEIGHTD10
0.115
0.096
0.345
0.075
0.232
0.376
0.371
2.788
0.214
0.599
GRAIN SIZE DISTRIBUTION
100
35.00
8.22
LL
B-01
B-02
B-03
B-03
B-03
0.08
3/4
U.S. SIEVE OPENING IN INCHES U.S. SIEVE NUMBERS
GRAVEL SAND
19
19
37.5
37.5
9.5
%Silt
0.54
1.24
B-01
B-02
B-03
B-03
B-03
2 2003
Cc CuClassification
%Clay
16
PID60 D30
coarse SILT OR CLAYfinemedium
GRAIN SIZE IN MILLIMETERS
3/8 50
2.5ft.
5.0ft.
5.0ft.
10.0ft.
20.0ft.
2.50ft.
5.00ft.
5.00ft.
10.00ft.
20.00ft.
PL
PROJECT NUMBER ES-7282 PROJECT NAME Harrington Redevelopment
GRAIN SIZE USDA ES-7282 HARRINGTON REDEVELOPMENT.GPJ GINT US LAB.GDT 2/24/21Earth Solutions NW, LLC
15365 N.E. 90th Street, Suite 100
Redmond, Washington 98052
Telephone: 425-449-4704
Fax: 425-449-4711
DocuSign Envelope ID: 9A2B0C09-72D8-490B-A60E-EAD24B2FAACB
Earth Solutions NW, LLC
Report Distribution
ES-7282
EMAIL ONLY Zarnoor Associates, LLC
c/o Mr. Karim Karmali
19515 North Creek Parkway, Suite 314
Bothell, Washington 98011
Attention: Mr. Nazim Karmali
EMAIL ONLY Grouparchitect
1735 Westlake Avenue North, Suite 200
Seattle, Washington 98109
Attention: Mr. Kyle Stevens
DocuSign Envelope ID: 9A2B0C09-72D8-490B-A60E-EAD24B2FAACB