APPROVED BLD2023-1219 APVD Fulton SFR - Geotech ReportU)
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April 12, 2023
ES-9113
RECEIVED
Oct 13 2023
CITY OF EDMONDS
DEVELOPMENT SERVICES
DEPARTMENT
BLD2023-1219
Earth
Solutions
NWLLC
Earth Solutions NW LLC
Geotechnical Engineering, Construction
Observation/Testing and Environmental Services
Mr. Jay Fulton REVIEWED
BY
8630 — 1 1 2th Lane Northeast CITY OF EDMONDS
Kirkland, Washington 98033 BUILDING DEPARTMENT:
Subject: Geotechnical Evaluation
Proposed Single -Family Residence
654 — 4' Avenue South
Edmonds, Washington
PLAN REVIEW ACCEPTANCE
FOR COMPLIANCE WITH THE APPLICABLE
CONSTRUCTION CODES IDENTIFIED BELOW.
® BUILDING ® STRUCTURAL
❑ MECHANICAL ❑ PLUMBING
❑ ELECTRICAL ® ENERGY
❑ ACCESSIBILITY ❑ FIRE
PLAN REVIEW ACCEPTANCE OF DOCUMENTS
DOES NOT AUTHORIZE CONSTRUCTION TO
PROCEED IN VIOLATION OF ANY FEDERAL,
STATE, OR LOCAL REGULATIONS.
BY: )ATE:02/22/2024
WE., cVAsj wut wNSULTANTS, INC.
Reference: Encompass Engineering & Surveying
Boundary & Topographic Survey, Job No. 22730, dated January 30, 2023
Minard, J.P.
Geologic Map MF-1541 (Edmonds East/West Quadrangles), dated 1983
Soil Survey of Snohomish County Area, Washington, issued July 1983
Palmer, S.P. et al.
Liquefaction Susceptibility Map of Snohomish County, dated September 2004
Snohomish County Planning and Development Services
Seismic Hazard Areas Map, dated February 1, 2016
City of Edmonds, Washington
1. Edmonds City Code (ECC) Chapter 23.80
2. Interactive GIS Mapping Portal
Dear Mr. Fulton:
As requested, Earth Solutions NW, LLC (ESNW) has prepared this geotechnical evaluation letter
report for the proposed project. We performed our work in general accordance with the scope of
services outlined in the proposal dated March 1, 2023, which was authorized on March 3, 2023.
A summary of the subsurface exploration, laboratory analyses, and recommendations with
respect to the proposed construction are provided in this letter report.
15365 N.E. 90th Street, Suite 100 0 Redmond, WA 98052 0 (425) 449-4704 0 FAX (425) 449-4711
Mr. Jay Fulton
April 12, 2023
Protect & Site Description
ES-9113
Page 2
The subject site is located immediately northwest of the intersection between 41h Avenue South
and Erben Drive, in Edmonds, Washington. The project area consists of one tax parcel
(Snohomish County Parcel No. 004096-001 -011 -00) and totals about 0.19 acres of land area.
The approximate site location is depicted on Plate 1 (Vicinity Map).
The property is currently developed with a single-family residence and associated improvements.
Per the referenced topographic survey, the existing topography is relatively level, with an
estimated maximum of about three feet of topographic relief across the property. The site is
bordered to the north and west by existing residential development and to the south and east by
Erben Drive and 41h Avenue South, respectively.
We understand the existing structure and site improvements will be removed, and a new single-
family residence with associated improvements will be constructed. At the time of letter report
preparation, neither site plans nor specific building load values were available for review;
however, we anticipate that the new single-family residence will consist of relatively lightly loaded
wood framing supported on conventional foundations. Based on our experience with similar
projects, we estimate wall loads of about 2 to 3 kips per linear foot and slab -on -grade loading of
150 pounds per square foot (psf) will be incorporated into the final design.
Subsurface Conditions
An ESNW representative observed, logged, and sampled two test pits on March 21, 2023. The
test pits were advanced at accessible locations within the property boundaries using a mini-
trackhoe and operator retained by ESNW. The test pits were completed to assess and classify
the site soils, to characterize the groundwater conditions within areas proposed for new
development, and to complete one small-scale Pilot Infiltration Test at a location designated by
the client. The maximum exploration depth was approximately seven -and -one-half feet below
the existing ground surface (bgs).
The approximate locations of the test pits are depicted on Plate 2 (Test Pit Location Plan). Please
refer to the attached test pit logs for a more detailed description of subsurface conditions.
Representative soil samples collected at the exploration locations were analyzed in general
accordance with Unified Soil Classification System (USCS) and United States Department of
Agriculture (USDA) methods and procedures.
Topsoil and Fill
Topsoil at the test pit locations was observed extending between 30 and 36 inches bgs. The
observed topsoil profiles were anomalously thick for typical topsoil thicknesses atop glacial drift
deposits in the Puget Sound region. Scrap metal and PVC plastic debris were encountered within
both test pit excavations and within the topsoil profiles, suggesting that the topsoil profile has
been thickened by the addition of organic fill (thus resulting in the relatively thick topsoil sections
observed). It is possible that deeper or shallower pockets of topsoil may be encountered locally
across the site. Topsoil can be characterized by its dark brown color, the presence of fine organic
material, and small root intrusions.
Earth Solutions NW. LLC
Mr. Jay Fulton ES-9113
April 12, 2023 Page 3
Neither structural fill nor non -organic fill were observed during the subsurface investigation. As
noted above, topsoil fill was observed at both test locations.
Native Soil
Underlying the topsoil and fill, native soils were encountered and characterized as transitional
bed deposits consisting primarily of medium dense to dense silty sand with gravel (USCS: SM).
Thin laminations and interbeds of silt and sand as well as iron oxide staining were noted within
the native deposits. Notably, cemented soils were not observed. The native transitional bed
deposits extended to the termination depth of both test pits.
Based on laboratory analyses of representative soil samples, the native transitional bed deposits
have a fines content between about 11 and 19 percent and were primarily observed in a moist to
wet condition at the time of exploration.
Geologic Setting
Geologic mapping of the area identifies transitional bed deposits (Qtb) as the primary geologic
unit underlying the subject site. Vashon glacial till (Qvt) is mapped immediately south and east
of the site, and Whidbey Formation sediments (Qw) are mapped immediately north and west of
the site.
Transitional bed deposits are characterized as both glacial and non -glacial deposits comprised
mostly of massive, thick or thin beds and laminae of clay, silt, and fine to very fine sand deposited
in lakes beyond the ice front and in fluvial systems prior to the advance of glacial ice.
Vashon glacial till is described as a non -sorted mixture of clay, silt, sand, and gravel in variable
amounts that was deposited directly beneath the glacier as it advanced over older sediment and
bedrock. Whidbey Formation sediments consist of bedded, compact, commonly oxidized,
medium to coarse grained sand, commonly exhibiting contorted bedding.
USDA soil mapping indicates the site is underlain by Everett very gravelly sandy loam on 0 to 8
percent slopes. Everett series soils formed on terraces and outwash plains in glacial outwash
soils. Per the referenced USDA soil survey, this soil unit maintains slow surface water runoff and
a slight hazard of water erosion.
In our opinion, the native soils observed during the subsurface exploration are representative of
transitional bed deposits and are generally consistent with the geologic and soil mapping
resources outlined in this section.
Groundwater
Natural groundwater seepage was not encountered during the March 2023 field exploration.
However, groundwater seepage is common within glacially derived deposits. In our opinion,
zones of perched groundwater should be expected within site excavations, especially if
construction occurs during the wet season. Groundwater seepage rates and elevations may
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.
Earth Solutions NW. LLC
Mr. Jay Fulton
April 12, 2023
Geologically Hazardous Areas Review
ES-9113
Page 4
ESNW reviewed ECC Chapter 23.80 to evaluate the presence of geologically hazardous areas
at the subject site. We also reviewed the City of Edmonds (City) online GIS resource, which
depicts suspected geologically hazardous areas within city limits. Geologically hazardous areas
in the City include areas susceptible to erosion, land sliding, earthquake, or other geological
events.
Based on our review, the site does not contain areas susceptible to erosion or landslide hazards.
However, a fault strand associated with the Southern Whidbey Island Fault zone is located within
about 500 feet (to the southwest) of the subject site. As such, seismic hazard is discussed in the
following section.
Seismic Hazard Areas
Seismic hazard areas in the City are areas subject to severe risk of damage as a result of
earthquake -induced ground shaking, slope failure, settlement, soil liquefaction, lateral spreading,
or surface faulting.
Liquefaction is a phenomenon that can occur within a soil profile as a result of an intense ground
shaking or loading condition. Most commonly, liquefaction is caused by ground shaking during
an earthquake. Soil profiles that are loose, cohesionless, and present below the groundwater
table are most susceptible to liquefaction. During the ground shaking, the soil contracts, and
porewater pressure increases. The increased porewater pressure occurs quickly and without
sufficient time to dissipate, resulting in water flowing upward to the ground surface and a liquefied
soil condition. Soil in a liquefied condition possesses very little shear strength in comparison to
the drained condition, which can result in a loss of foundation support for structures.
In our opinion, and consistent with the depiction on the referenced liquefaction susceptibility map,
site susceptibility to liquefaction may be considered very low. The absence of a shallow
groundwater table and the relatively dense and fine-grained characteristics of the native soil were
the primary bases for this opinion.
Fault mapping resources indicate an inferred Class B fault trace, in association with the Southern
Whidbey Island Fault Zone, is located within about 500 feet (to the southwest) of the subject site,
trending in a northwest -southeast orientation. Class B faults are defined as faults for which
Quaternary -age (within the past 2,588,000 years) deformation is suspected but insufficient
evidence has been gathered to support the determination. The locations and activity of Class B
faults are inferred based on best available data but have not been confirmed.
During the fieldwork, ESNW did not observe any evidence of faulting, deformation, or other
disturbances within the native stratigraphy or surficial geomorphology. We also reviewed readily
available LIDAR mapping resources for evidence of fault scarps or associated linear features on
site and in the surrounding area. No evidence of surficial deformation was observed during
LIDAR review.
Earth Solutions NW. LLC
Mr. Jay Fulton ES-9113
April 12, 2023 Page 5
With respect to the subject site, earthquake magnitude would be dictated by the type of
earthquake event, e.g., shallow crustal, intra-plate, or subduction zone event. Although evidence
of shallow faults and related lineaments have been identified throughout the Puget Sound region
(Seattle Fault, South Whidbey Island Fault Zone, and others), evidence of surface fault
expressions on or in the vicinity of the subject site has not been identified. In any case, seismic
activity associated with a shallow crustal event would be expected to produce relatively low to
moderate earthquake magnitude of relatively short duration. In terms of larger magnitude events
associated with intra-plate and subduction zone events, distance between the source of these
events and the site is expected to be greater. However, a longer duration of ground shaking
would likely occur.
Based on the field observations and analysis outlined above, it is our opinion the risk of surface
rupture during a seismic event is very low to negligible, and the site does not meet the ECC
definition of a seismic hazard area.
Geotechnical Recommendations
In our opinion, construction of the proposed single-family residence is feasible from a
geotechnical standpoint. The geotechnical recommendations, conclusions, and considerations
provided in the following sections are intended to support the proposed construction.
In -situ and Imported Soil
The in -situ soils encountered at the subject site generally have a moderate to high sensitivity to
moisture and were generally in a moist to wet condition at the time of exploration. Soils
anticipated to be exposed on site will degrade if exposed to wet weather and construction traffic.
Compaction of the soils to the levels necessary for use as structural fill may be difficult or
impossible during wet weather conditions. Soils encountered during site excavations that are
excessively over the optimum moisture content will likely require aeration or treatment prior to
placement and compaction. Conversely, soils that are substantially below the optimum moisture
content will require moisture conditioning (by adding water) prior to use as structural fill. An
ESNW representative should be contacted to evaluate the suitability of in -situ soils for use as
structural fill at the time of construction.
Imported soil intended for use as structural fill should be evaluated by ESNW during construction.
The imported soil must be workable to the optimum moisture content, as determined by the
Modified Proctor Method (ASTM D1557), at the time of placement and compaction. 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).
Earth Solutions NW. LLC
Mr. Jay Fulton
April 12, 2023
Structural Fill
ES-9113
Page 6
Structural fill is defined as compacted soil placed in foundation, slab -on -grade, roadway,
permanent slope, retaining wall, and utility trench backfill areas. Soils placed in structural areas
should be placed in loose lifts of 12 inches or less and compacted to a relative compaction of 95
percent, based on the laboratory maximum dry density as determined by the Modified Proctor
Method (ASTM D1557). For soil placed in utility trenches underlying structural areas, compaction
requirements are dictated by the local city, county, or utility district, and are typically specified to
a relative compaction of at least 95 percent.
Subgrade Preparation
Following site stripping, ESNW should be contacted to observe the subgrade to confirm soil
conditions are as anticipated and to provide supplementary recommendations for subgrade
preparation, as necessary. In general, foundation subgrade on native cut surfaces should be
compacted in situ to a minimum depth of one foot below the design subgrade elevation.
Where encountered, existing fill soils should be removed and/or reworked to the specifications of
structural fill previously detailed in this letter report. Topsoil and organic -rich soils are not suitable
for structural support and should be removed from areas proposed for new structural loading.
Uniform compaction of structural fill and the foundation and slab subgrade areas will establish a
relatively consistent subgrade condition below the foundation and slab elements. Supplementary
recommendations for subgrade improvement may be provided at the time of construction and
would likely include further mechanical compaction or overexcavation and replacement with
suitable structural fill.
Void Space Restoration
The process of removing the existing structures may produce voids where existing foundations
are removed and where crawl space areas may have been present. Complete restoration of
voids from old foundation areas must be executed as part of the subgrade preparation activities.
The following guidelines for preparing subgrade areas should be incorporated into the final
design:
• Where voids and related demolition disturbances extend below planned subgrade
elevations, restoration of these areas should be completed. Structural fill should be used
to restore voids or unstable areas resulting from the removal of existing structural
elements.
• Recompact, or overexcavate and replace, areas of existing fill exposed at the design
subgrade elevations. Overexcavations should extend into competent native soils and
structural fill should be utilized to restore subgrade elevations, as necessary.
• ESNW should confirm subgrade conditions, as well as the required level of recompaction
and/or overexcavation and replacement, during site preparation activities. ESNW should
also evaluate the overall suitability of prepared subgrade areas following site preparation
activities.
Earth Solutions NW. LLC
Mr. Jay Fulton
April 12, 2023
Foundations
ES-9113
Page 7
The proposed residential structure can be supported on conventional spread and continuous
footings bearing on undisturbed (competent) native soil, compacted native soil or structural fill, or
new structural fill placed atop a competent subgrade surface. Thick sections of topsoil fill were
encountered at the test pit locations extending at least 30 to 36 inches bgs in the western portion
of the site. Where encountered, the existing organic -rich fill soils should be removed from
structural areas of the site.
In general, competent native soil suitable for support of foundations will likely be encountered
beginning at depths of about three feet bgs. Where loose or unsuitable soil conditions are
encountered at foundation subgrade elevations, compaction of the soils to the specifications of
structural fill or overexcavation and replacement with suitable structural fill will likely be
necessary. An ESNW representative should be contacted to confirm the suitability of foundation
subgrades at the time of construction.
Provided the structures will be supported as described above, the following parameters may be
used for design of the new foundations:
• Allowable soil bearing capacity 2,500 psf
• Passive earth pressure
• Coefficient of friction
300 pcf
NE,I K
A one-third increase in the allowable soil bearing capacity can be assumed for short-term wind
and seismic loading conditions. The passive earth pressure and coefficient of friction values
include a safety factor of 1.5. With structural loading as expected, total settlement in the range
of one inch is anticipated, with differential settlement of about one-half inch. Most of the
anticipated settlement should occur during construction as dead loads are applied.
Slab -on -Grade Floors
Slab -on -grade floors for the proposed residence should be supported on competent, firm, and
unyielding subgrades comprised of competent native soil or compacted structural fill. Unstable
or yielding subgrade areas should be recompacted or overexcavated and replaced with suitable
structural fill prior to slab construction. As noted previously in this letter report, areas with existing
fill soil should be removed and/or reworked to the specifications of structural fill. Organic -rich
soils should be removed from slab subgrades 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 (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. If a vapor barrier is to be utilized, it should be a material specifically designed for
use as a vapor barrier and should be installed in accordance with the specifications of the
manufacturer.
Earth Solutions NW. LLC
Mr. Jay Fulton ES-9113
April 12, 2023 Page 8
Retaining Walls
Retaining walls must be designed to resist earth pressures and applicable surcharge loads. The
following parameters may be used for retaining wall design:
• Active earth pressure (unrestrained condition)
• At -rest earth pressure (restrained condition)
• Traffic surcharge* (passenger vehicles)
• Passive earth pressure
• Coefficient of friction
• Seismic surcharge
* Where applicable.
t Where H equals the retained height (in feet).
35 pcf
55 pcf
70 psf (rectangular distribution)
300 pcf
0.40
8H psft
The above passive earth pressure and coefficient of friction values include a safety factor of 1.5.
Additional surcharge loading from adjacent foundations, sloped backfill, or other 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.
Drainage should be provided behind retaining walls such that hydrostatic pressures do not
develop. If drainage is not provided, hydrostatic pressures should be included in the wall design.
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.
Drainage
Groundwater seepage is likely to be encountered within site excavations depending on the time
of year grading operations take place. 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 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. Water must
not be allowed to pond adjacent to structures. The grade adjacent to the buildings should be
sloped away at a gradient of at least 2 percent for a horizontal distance of at least four feet. In
our opinion, a foundation drain should be installed along building perimeter footings. A typical
foundation drain detail is provided on Plate 4.
Earth Solutions NW. LLC
Mr. Jay Fulton
April 12, 2023
Infiltration Feasibility
ES-9113
Page 9
ESNW completed one small-scale Pilot Infiltration Test (PIT) at test location TP-2 at a depth of
approximately four -and -one-half feet bgs. The small-scale PIT was completed in general
accordance with the applicable requirements of the 2019 Stormwater Management Manual for
Western Washington (2019 SWMMWW), which has been adopted by the City for flow control
design.
Based on the results of the PIT, the measured (short-term) infiltration rate recorded at the
conclusion of the infiltration testing was 0.8 inches per hour (in/hr). Per the 2019 SWMMWW, a
series of correction factors must be applied to the measured rate to calculate an appropriate
design rate. The following correction factors were selected:
• Site variability, CFv 0.7
• Test method, CFT 0.5
• Maintenance, CFm 0.9
Upon incorporation of the correction factors, a design (long-term) infiltration rate of 0.25 in/hr is
recommended for this site. Because this rate is relatively low, full infiltration is not considered
feasible from a geotechnical standpoint; however, small-scale (or limited -scale) flow control BMP
implementation may be feasible depending on BMP type, location, and depth. In any case,
overflow provisions are recommended for any flow control BMP design element on this site, and
in the event overflow provisions are not or cannot be incorporated into the design, it is our opinion
infiltration should not be considered feasible from a geotechnical standpoint.
Regarding groundwater protection, and in accordance with the subsurface characterization
criteria for infiltration BMPs (outlined in Chapter 5 of Volume V of the 2019 SWMMWW), shallow
samples of topsoil were collected and are being held in our laboratory for future organic content
and cation exchange capacity analyses, upon request. The samples will be discarded after 60
days unless requested otherwise by the client.
ESNW can provide additional consulting services and design considerations regarding infiltration
and/or BMP feasibility, upon request. ESNW should be contacted to confirm suitable native soils
are exposed at the design facility subgrade elevation(s) and location(s) during construction.
Earth Solutions NW. LLC
Mr. Jay Fulton
April 12, 2023
Seismic Design
ES-9113
Page 10
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 test pit locations, the parameters and values provided below are recommended for seismic
design per the 2018 IBC.
Parameter
Value
Site Class
D*
Mapped short period spectral response acceleration, Ss (g)
1.283
Mapped 1-second period spectral response acceleration, S1 (g)
0.451
Short period site coefficient, Fa
1.0
Long period site coefficient, Fv
1.849t
Adjusted short period spectral response acceleration, SMs (g)
1.283
Adjusted 1-second period spectral response acceleration, Sm1 (g)
0.834t
Design short period spectral response acceleration, SIDS (g)
0.856
Design 1-second period spectral response acceleration, SD1 (g)
0.556t
Assumes medium dense to dense native soil conditions, encountered to a maximum depth of seven -and -one-half
feet bgs during the March 2023 field exploration, remain dense to at least 100 feet bgs.
t Values assume Fv maybe determined using linear interpolation per Table 11.4-2 in ASCE 7-16.
As indicated in the table footnote, several of the seismic design values provided above are
dependent on the assumption that site -specific ground motion analysis (per Section 11.4.8 of
ASCE 7-16) will not be required for the subject project. ESNW recommends the validity of this
assumption be confirmed at the earliest available opportunity during the planning and early
design stages of the project. Further discussion between the project structural engineer, the
project owner, 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 susceptibility is discussed in the Seismic Hazard Areas section in this report.
Earth Solutions NW. LLC
Mr. Jay Fulton
April 12, 2023
Limitations & Additional Services
ES-9113
Page 11
This letter report has been prepared for the exclusive use of Mr. Jay Fulton and his
representatives. The recommendations and conclusions provided in this letter report 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. A warranty is neither
expressed nor implied. If the design assumptions outlined herein either change or are incorrect,
ESNW should be contacted to review the recommendations provided in this letter report. ESNW
should be contacted to review the final design to confirm that our geotechnical recommendations
have been incorporated into the plans.
ESNW should be retained to provide earthwork observations and testing services during
construction. Variations in the soil and groundwater conditions observed at the exploration
locations may exist and may not become evident until construction. ESNW should reevaluate
the conclusions provided in this letter report if variations are encountered.
We appreciate the opportunity to be of service to you and trust this letter meets your current
needs. Should you have any questions, or require additional information, please call.
Sincerely,
EARTH SOLUTIONS NW, LLC
b'1W6-- �Ly
Brian C. Snow, G.I.T.
Senior Staff Geologist
04/12/2023
Keven D. Hoffmann, P.E.
Associate Principal Engineer
Attachments: Plate 1 — Vicinity Map
Plate 2 — Test Pit Location Plan
Plate 3 — Retaining Wall Drainage Detail
Plate 4 — Footing Drain Detail
Test Pit Logs
Grain Size Distribution
Earth Solutions NW. LLC
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Reference: NORTHsollutions
Earth 1
Snohomish County, Washington
Observation/Testing00!
Open StreetMap.org
40
Vicinity Map
Fulton Property
Edmonds, Washington
Drawn MRS
Date 04/07/2023
Proj. No. 9113
NOTE: This plate may contain areas of color. ESNW cannot be
responsible for any subsequent misinterpretation of the information
Checked BCS
Date April 2023
Plate 1
resulting from black & white reproductions of this plate.
i
69 _ � ` 701
69 -
W TP=2 — ; 'I72
70
_—I
72
ERBEN DRIVE
LEGEND
TP-1 Approximate Location of
— . — ESNW Test Pit, Proj. No.
ES-9113, Mar. 2023
Subject Site
= Existing Building
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.
NORTH
0 15 30 60
1 "=30' � �
Scale in Feet
Test Pit Location Plan
Fulton Property
Edmonds, Washington
NOTE: This plate may contain areas of color. ESNW cannot be Drawn MRS Date 04/07/2023 Pro No. 9113
responsible for any subsequent misinterpretation of the information 1
resulting from black & white reproductions of this plate. Checked BCS Date April 2023 Plate 2
18" Min.
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o
0 0 0 0 oo .0 o, o 8 0
00 o o oo O
0
0 0 0 o o o o
O o0 o oo op o°
0 o o 0 0 0 0 o 0
0 0 o0 00° 0 o o
00 0 op oo 0 o o o
0
0 0o Oo 0 0 Oo0o O oo o
00
00
0 0 oo o p
o
o�oo ...0. 00 0 0 8
0 0 0 0 oo
0 0 0 000 o0 o 000
o 0 0 0 g o
Ooop o 0 0o 00 p o oo
0
0 o So o0 0 0 0 0
o 0 0
00 o o 00 0 000 8 Oo
0 & o p 0o0o o Oo
.0 0 0�?,
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:
Q 00o O
p o000 Free -draining Structural Backfill
-inch Drain Rock
%. of of of ti
Structural
Fill
Perforated Rigid Drain Pipe
(Surround in Drain Rock)
SCHEMATIC ONLY - NOT TO SCALE
NOT A CONSTRUCTION DRAWING
Retaining Wall Drainage Detail
Fulton Property
Edmonds, Washington
Drawn MRS Date 04/07/2023 Proj. No. 9113
Checked BCS Date April 2023 1 Plate 3
Perforated Rigid Drain Pipe
(Surround in Drain Rock)
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:
FTT Surface Seal: native soil or
other low -permeability material.
1-inch Drain Rock
.tilti?ti?ti:'
SCHEMATIC ONLY - NOT TO SCALE
NOT A CONSTRUCTION DRAWING
Drawn MRS Date 04/07/2023 Proj. No. 9113
Checked BCS Date April 2023 Plate 4
W
I
,1� ��
Well -graded gravel with
Moisture Content
Symbols
m
CU >
GW
or without sand, little to
0
c
no fines
Dry - Absence of moisture, dusty, dry to
Cement grout
U U
j L
11
the touch
ATD = At time
surface seal
0
O
o
o
of drilling
g
Bentonite
o p
o01 00(lo
Poorly graded gravel with
Damp Perceptible moisture, likely below
chips
o Z
v
UU
o 0 0 0
GP
or without sand, little to
optimum MC
Static water
i
LO C
o
Q�oQ
no fines
level (date)
eall
Co °
Moist - Damp but no visible water, likely
o
a)
H a)
at/near optimum MC
-
Filter pack with
65
0
a) tav,
0
0
uD
op
o
GM
Silty gravel with or without
Wet - Water visible but not free draining,
blank casing
section
o
0
2 �
O
Q
0
sand
likely above optimum MC
Screened casing
o
or Hydrotip with
U) °
0 .0
o
Saturated/Water Bearing - Visible free
filter pack
o
U)
0
�
Clayey gravel with or
water, typically below groundwater table
End cap
O
-0-0
�
° L
L LL
C7
^
GC
without sand
Terms Describing Relative Density and Consistency
_ 0
co Z
Coarse -Grained Soils: Test Symbols & Units
Well -graded sand with
u�
O
SW
or without gravel, little to
=
Density SPT blows/foot Fines Fines Content
( )
oo
N
o
c
IL
o°o°o°o°o°o
°°°°°°°°°°°
no fines
Very Loose < 4
O LO
U
._
U (n
o
MC =Moisture Content (%)
Loose 4 to 9
'::
ca
�
0
to
,
•:: •..:•.;: , .
Poorly graded sand with
DD = Dr Density cf
Medium Dense 10 to 29 Y Y (P )
a)o
v
Sp
or without gravel, little to
o Z
no fines
Dense 30 to 49 Str = Shear Strength (tsf)
0
a)Very
Dense _> 50
O U)
PID = Photoionization Detector (ppm)
co
a�
'.:'
.
SM
Silty sand with or without
o
Lo c
c
:;:
.::'•:.
;..
gravel
Fine -Grained Soils: OC = Organic Content (%)
e
.
•;.
Consistency SPT blows/foot CEC = Cation Exchange Capacity (meq/100 g)
:
Very Soft < 2
�
�
SC
Clayey sand with or
LL = Liquid Limit (%)
Soft 2 to 3
^
without gravel
Medium Stiff 4 to 7 PL = Plastic Limit (%)
(%)
Stiff 8 to 14 PI = Plasticity IndexLO
CD
Silt with or without sand
IVIL
or gravel; sandy or
Very Stiff 15 to 29
gravelly silt
Hard _> 30
0
0 0
U 0
F///
Clay of low to medium
Y
Component Definitions
>
a)—.1
plasticity; plasticity; lean clay with
cn
M t.
or without sand or gravel;
Descriptive Term Size Range and Sieve Number
00
cn E
sandy or gravelly lean clay
Boulders Larger than 12"
— —
_
�
rn .
— J
U .5
Cobbles 3" to 12"
�o
_
OL
Organic clay or silt of
Zo
—
low plasticity
Gravel 3" to No. 4 (4.75 mm)
-0 to
J
�_
—
Coarse Gravel 3" to 3/4"
Fine Gravel 3/4" to No. 4 (4.75 mm)
Elastic silt with or without
d
Sand No. 4 (4.75 mm) to No. 200 (0.075 mm)
0
0
o
MH
sand or gravel; sandy or
Coarse Sand No. 4 (4.75 mm) to No. 10 (2.00 mm)
c O
(n g
gravelly elastic silt
Medium Sand No. 10 (2.00 mm) to No. 40 (0.425 mm)
IL 2
>, -
Fine Sand No. 40 (0.425 mm) to No. 200 (0.075 mm)
0 °o U O
Clay of high plasticity;
Silt and Clay Smaller than No. 200 (0.075 mm)
o
-0 LO
CH
fat clay with or without
Modifier Definitions
o
E
sand or gravel; sandy or
J
gravelly fat clay
—_
Percentage by
fn
Weight (Approx.) Modifier
CY
OH
Organic clay or silt of
medium to high plasticity
< 5 Trace (sand, silt, clay, gravel)
5 to 14 Slightly (sandy, silty, clayey, gravelly)
o>
ca o
PT
Peat, muck, and other
15 to 29 Sandy, silty, clayey, gravelly
=
�U)
— =
highly organic soils
Q
_> 30 Very (sandy, silty, clayey, gravelly)
Classifications of soils in this geotechnical report and as shown on the exploration logs are based on visual
—
field and/or laboratory observations, which include density/consistency, moisture condition, grain size, and
ii
FILL
Made Ground
plasticity estimates, and should not be construed to imply field or laboratory testing unless presented herein.
Visual -manual and/or laboratory classification methods of ASTM D2487 and D2488 were used as an
identification guide for the Unified Soil Classification System.
Earth
Solutions
NW L�c
Earth Solutions NWLLC
Geotechnical Engineering, Construction
Observation/Testing and Environmental Services
EXPLORATION LOG KEY
r Earth Solutions NW, LLC
15365 N.E. 90th Street, Suite 100
Redmond, Washington 98052
Telephone: 425-449-4704
Fax: 425-449-4711
PROJECT NUMBER ES-9113
DATE STARTED 3/21/23 COMPLETED 3/21/23
EXCAVATION CONTRACTOR NW Excavating
LOGGED BY BCS CHECKED BY KDH
NOTES
SURFACE CONDITIONS Lawn grass
TEST PIT NUMBER TP-1
PAGE 1 OF 1
PROJECT NAME Fulton Prooert
GROUND ELEVATION 70 ft
LATITUDE 47.8044 LONGITUDE-122.3793
GROUND WATER LEVEL:
V AT TIME OF EXCAVATION
AFTER EXCAVATION
W
CL
_
wJ
~W
CO
TESTS
_
Q O
MATERIAL DESCRIPTION
p
CL
fy
Q Z
0
co
0.0
Dark brown TOPSOIL (Fill)
-abundant small to medium root intrusions
TPSL
1
-probed 18"
MC - 19.0
-scrap metal debris
intermixed brown silty SAND, potential relic weathered zone
2.5
Gray silty SAND with gravel, dense, moist to wet
-light to moderate iron oxide staining
MC = 22.8
-thin interbeds of silt/sand
SM
-decreasing fines content
-probed 3"
MC = 17.0 6.0
Test pit terminated at 6.0 feet below existing grade. No groundwater encountered during
excavation. No caving observed.
LIMITATIONS: Ground elevation (if listed) is approximate; the test location was not
surveyed. Coordinates are approximate and based on the WGS84 datum. Do not rely on
this test log as a standalone document. Refer to the text of the geotechnical report for a
complete understanding of subsurface conditions.
J
J
W
d
F
2
0]
J
Q
Uj
W
Z
W
Earth Solutions NW, LLC TEST PIT NUMBER TP-2
YPRII 15365 N.E. 90th Street, Suite 100 PAGE 1 OF 1
Redmond, Washington 98052
Telephone: 425-449-4704
Fax: 425-449-4711
PROJECT NUMBER ES-9113 PROJECT NAME Fulton Property
DATE STARTED 3/21/23 COMPLETED 3/21/23 GROUND ELEVATION 70 ft
EXCAVATION CONTRACTOR NW Excavating LATITUDE 47.80429 LONGITUDE-122.37944
LOGGED BY BCS CHECKED BY KDH GROUND WATER LEVEL:
NOTES SZ AT TIME OF EXCAVATION
SURFACE CONDITIONS Lawn grass AFTER EXCAVATION
w
_
~W
_
wJ
CO
TESTS
Q O
MATERIAL DESCRIPTION
p
CL
W
Q Z
0
0.0
Dark brown TOPSOIL (Fill)
MC = 22.2
-abundant medium to large root intrusions to 2.5'
TPSL
-scattered PVC fragments
2.5 MC = 20.7 2.5
67.5
Brown silty SAND with gravel, medium dense to dense, moist
MC = 11.2
Fines = 11.4
[USDA Classification: very gravelly loamy SAND]
-probed 8"
-infiltration test
MC = 13.0
Fines = 18.4
[USDA Classification: gravelly loamy SAND]
5.0 SM
-increased post-test moisture content
MC = 21.3
[USDA Classification: gravelly sandy LOAM]
7.5 MC=14.3 7.5
62.5
Fines = 19.1
Test pit terminated at 7.5 feet below existing grade. No groundwater encountered during
excavation. No caving observed.
LIMITATIONS: Ground elevation (if listed) is approximate; the test location was not
surveyed. Coordinates are approximate and based on the WGS84 datum. Do not rely on
this test log as a standalone document. Refer to the text of the geotechnical report for a
complete understanding of subsurface conditions.
Earth Solutions NW, LLC GRAIN SIZE DISTRIBUTION
15365 N.E. 90th Street, Suite 100
WWI Redmond, Washington 98052
Telephone: 425-449-4704
Fax: 425-449-4711
PROJECT NUMBER ES-9113 PROJECT NAME Fulton Property
U.S. SIEVE OPENING IN INCHES U.S. SIEVE NUMBERS I HYDROMETER
6 4 3 2 1Z 1 1 /23/8 3 4 6 810 1416 20 30 40 50 60 100140 200
100
95
90
85
80
75
70
65
H
x
cD
60
w
� 55
m
w 50
z
LL
45
z
w
40
w
a
35
30
25
20
15
10
5
0
100 10 1 0.1 0.01 0.001
GRAIN SIZE IN MILLIMETERS
COBBLES
GRAVEL
SAND
SILT OR CLAY
fine
coarse medium fine