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GEOTECHNICAL ENGINEERING REPORT
PREPARED BY:
THE RILEY GROUP, INC.
17522 BOTHELL WAY NORTHEAST
BOTHELL, WASHINGTON 98011
PREPARED FOR:
ANITA WOO
12906 NORTHEAST 25TH PLACE
BELLEVUE, WASHINGTON 98004
RGI PROJECT NO. 2018-070
JEFFERSON AND KIRKLAND TOWNHOMES
1513 KIRKLAND AVENUE NORTHEAST AND
1526 JEFFERSON AVENUE NORTHEAST
RENTON, WASHINGTON
APRIL 6, 2018
Geotechnical Engineering Report i April 6, 2018
Jefferson and Kirkland Townhomes, Renton, Washington RGI Project No. 2018-070
TABLE OF CONTENTS
1.0 INTRODUCTION ............................................................................................................................... 1
2.0 PROJECT DESCRIPTION ............................................................................................................... 1
3.0 FIELD EXPLORATION AND LABORATORY TESTING .......................................................... 2
3.1 FIELD EXPLORATION ................................................................................................................................... 2
3.2 LABORATORY TESTING ................................................................................................................................ 2
4.0 SITE CONDITIONS ........................................................................................................................... 2
4.1 SURFACE .................................................................................................................................................. 2
4.2 GEOLOGY ................................................................................................................................................. 3
4.3 SOILS ....................................................................................................................................................... 3
4.4 GROUNDWATER ........................................................................................................................................ 3
4.5 SEISMIC CONSIDERATIONS ........................................................................................................................... 4
4.6 GEOLOGIC HAZARD AREAS .......................................................................................................................... 4
5.0 DISCUSSION AND RECOMMENDATIONS ................................................................................. 5
5.1 GEOTECHNICAL CONSIDERATIONS ................................................................................................................. 5
5.2 EARTHWORK ............................................................................................................................................. 5
5.2.1 Erosion and Sediment Control ..................................................................................................... 5
5.2.2 Stripping and Subgrade Preparation ............................................................................................ 6
5.2.3 Excavations................................................................................................................................... 6
5.2.4 Structural Fill ................................................................................................................................ 7
5.2.5 Wet Weather Construction Considerations ................................................................................. 8
5.3 FOUNDATIONS .......................................................................................................................................... 9
5.4 RETAINING WALLS ................................................................................................................................... 10
5.5 SLAB-ON-GRADE CONSTRUCTION ............................................................................................................... 10
5.6 DRAINAGE .............................................................................................................................................. 11
5.6.1 Surface ....................................................................................................................................... 11
5.6.2 Subsurface .................................................................................................................................. 11
5.6.3 Infiltration .................................................................................................................................. 11
5.7 UTILITIES ................................................................................................................................................ 12
6.0 ADDITIONAL SERVICES .............................................................................................................. 12
7.0 LIMITATIONS ................................................................................................................................. 12
LIST OF FIGURES AND APPENDICES
Figure 1 ..................................................................................................................... Site Vicinity Map
Figure 2 ............................................................................................... Geotechnical Exploration Plan
Figure 3 ............................................................................................... Retaining Wall Drainage Detail
Figure 4 ....................................................................................................Typical Footing Drain Detail
Appendix A .......................................................................... Field Exploration and Laboratory Testing
Geotechnical Engineering Report ii April 6, 2018
Jefferson and Kirkland Townhomes, Renton, Washington RGI Project No. 2018-070
Executive Summary
This Executive Summary should be used in conjunction with the entire Geotechnical
Engineering Report (GER) for design and/or construction purposes. It should be
recognized that specific details were not included or fully developed in this section, and
the GER must be read in its entirety for a comprehensive understanding of the items
contained herein. Section 7.0 should be read for an understanding of limitations.
RGI’s geotechnical scope of work included the advancement of five test pits to
approximate depths of 5 to 9.5 feet below existing site grades.
Based on the information obtained from our subsurface exploration, the site is suitable
for development of the proposed project. The following geotechnical considerations were
identified:
Soil Conditions: The soils encountered during field exploration include loose to medium
dense fill comprised of silty sand with trace gravel and sand with some silt and trace
gravel over native deposits of loose to dense silty sand with varying amounts of gravel,
sand with varying amounts of silt and gravel and gravel with varying amounts of sand and
silt. Very dense glacial till comprised of silty sand with some gravel was encountered at
one location.
Groundwater: No groundwater seepage was encountered during our subsurface
exploration.
Foundations: Foundations for the proposed building may be supported on conventional
spread footings bearing on medium dense to dense native soil or structural fill.
Slab-on-grade: Slab-on-grade floors and slabs for the proposed building can be supported
on medium dense to dense native soil or structural fill.
Geotechnical Engineering Report 1 April 6, 2018
Jefferson and Kirkland Townhomes, Renton, Washington RGI Project No. 2018-070
1.0 Introduction
This Geotechnical Engineering Report (GER) presents the results of the geotechnical
engineering services provided for the Jefferson and Kirkland Townhomes in Renton,
Washington. The purpose of this evaluation is to assess subsurface conditions and
provide geotechnical recommendations for the construction of 11 townhomes. Our scope
of services included field explorations, laboratory testing, engineering analyses, and
preparation of this GER.
The recommendations in the following sections of this GER are based upon our current
understanding of the proposed site development as outlined below. If actual features
vary or changes are made, RGI should review them in order to modify our
recommendations as required. In addition, RGI requests to review the site grading plan,
final design drawings and specifications when available to verify that our project
understanding is correct and that our recommendations have been properly interpreted
and incorporated into the project design and construction.
2.0 Project description
The project site is located at 1513 Kirkland Avenue Northeast and 1526 Jefferson Avenue
Northeast in Renton, Washington. The approximate location of the site is shown on
Figure 1.
The site is currently occupied by two multi-family homes, one adjacent to Jefferson
Avenue Northeast and one adjacent to Kirkland Avenue Northeast. Several outbuildings
also occupy the site. RGI understands that 11 townhomes will be constructed at the site.
Based on review of a proposed site layout prepared by Daniel Umbach Architect, 6 units
will be located along Jefferson Avenue Northeast, and 5 units along Kirkland Avenue
Northeast. Vehicle access will be via a paved driveway extending west from Kirkland
Avenue Northeast in the southeast site corner, with garages in the lower level of each
unit. RGI understands the central portion of the site is being considered for infiltration of
stormwater.
At the time of preparing this GER, building plans were not available for our review. Based
on our experience with similar construction, RGI anticipates that the proposed building
will be supported on perimeter walls with bearing loads of two to six kips per linear foot,
and a series of columns with a maximum load up to 30 kips. Slab-on-grade floor loading of
250 pounds per square foot (psf) are expected.
Geotechnical Engineering Report 2 April 6, 2018
Jefferson and Kirkland Townhomes, Renton, Washington RGI Project No. 2018-070
3.0 Field Exploration and Laboratory Testing
3.1 FIELD EXPLORATION
On March 30, 2018, RGI observed the excavation of five test pits and completed one
infiltration test. The approximate exploration locations are shown on Figure 2.
Field logs of each exploration were prepared by the geologist that continuously observed
the excavation. These logs included visual classifications of the materials encountered
during excavation as well as our interpretation of the subsurface conditions between
samples. The test pits logs included in Appendix A represent an interpretation of the field
logs and include modifications based on laboratory observation and analysis of the
samples.
3.2 LABORATORY TESTING
During the field exploration, a representative portion of each recovered sample was
sealed in containers and transported to our laboratory for further visual and laboratory
examination. Selected samples retrieved from the test pits were tested for moisture
content and grain size analysis to aid in soil classification and provide input for the
recommendations provided in this GER. The results and descriptions of the laboratory
tests are enclosed in Appendix A.
4.0 Site Conditions
4.1 SURFACE
The subject site is comprised of two rectangular-shaped parcels of land totaling
approximately 0.77 acres in size. The site is bound to the north and south by residential
properties, to the east by Kirkland Avenue Northeast, and to the west by Jefferson
Avenue Northeast.
The existing site is occupied by two multi-family homes and several outbuildings. A
concrete slab that appears to be from a garage is located in the northeast site corner.
Several small brick walls and numerous fences divide the property into four yard areas.
The site is relatively flat with about five feet of elevation change across the site. The site
slopes down from the streets along the east and west perimeter to a topographic low
extending in a north-south direction through the central portion of the property, which
has a slight slope toward the south. The site is vegetated primarily with grass, with
numerous decorative plants, shrubs, and fruit trees scattered about the property. A large-
diameter cedar tree is located in the south-central portion of the property.
Geotechnical Engineering Report 3 April 6, 2018
Jefferson and Kirkland Townhomes, Renton, Washington RGI Project No. 2018-070
4.2 GEOLOGY
Review of the Preliminary Geologic Map of Seattle and Vicinity, Washington, by Howard
H. Waldron, etc. (1962) indicates that the soil in the project vicinity is mapped as Vashon
till (Qt), which is light to dark gray, nonsorted, nonstratified mixture of clay, silt, sand, and
gravel. Till was encountered at a depth of 9 feet in TP-1, and likely underlies the entire
property. The sand and gravel soils encountered above the till throughout the site match
the descriptions for Younger Sand (Qys) and Younger Gravel (Qyg) mapped to the west
and northwest of the site.
4.3 SOILS
The soils encountered during field exploration include loose to medium dense fill
comprised of silty sand with trace gravel and sand with some silt and trace gravel over
native deposits of loose to dense silty sand with varying amounts of gravel, sand with
varying amounts of silt and gravel and gravel with varying amounts of sand and silt. Very
dense glacial till comprised of silty sand with some gravel was encountered at one
location.
More detailed descriptions of the subsurface conditions encountered are presented in
the test pits included in Appendix A. Sieve analysis was performed on seven selected soil
samples. Grain size distribution curves are included in Appendix A.
4.4 GROUNDWATER
No groundwater seepage was encountered during our subsurface exploration. Iron oxide
staining was observed that may be indicative of seasonal groundwater travelling through
subsurface soils.
It should be recognized that fluctuations of the groundwater table will occur due to
seasonal variations in the amount of rainfall, runoff, and other factors not evident at the
time the explorations were performed. In addition, perched water can develop within
seams and layers contained in fill soils or higher permeability soils overlying less
permeable soils following periods of heavy or prolonged precipitation. Therefore,
groundwater levels during construction or at other times in the future may be higher or
lower than the levels indicated on the logs. Groundwater level fluctuations should be
considered when developing the design and construction plans for the project.
Geotechnical Engineering Report 4 April 6, 2018
Jefferson and Kirkland Townhomes, Renton, Washington RGI Project No. 2018-070
4.5 SEISMIC CONSIDERATIONS
Based on the 2012/2015 International Building Code (IBC), RGI recommends the follow
seismic parameters for design.
Table 1 2012/2015 IBC
Parameter Value
Site Soil Class1 D2
Site Latitude 47.50635oN
Site Longitude 122.17967oW
Short Period Spectral Response Acceleration, SS (g) 1.426
1-Second Period Spectral Response Acceleration, S1 (g) 0.537
Adjusted Short Period Spectral Response Acceleration, SMS (g) 1.426
Adjusted 1-Second Period Spectral Response Acceleration, SM1 (g) 0.806
1. Note: In general accordance with Chapter 20 of ASCE 7-10. The Site Class is based on the average characteristics of the upper 100
feet of the subsurface profile.
2. Note: The 2012/2015 IBC and ASCE 7-10 require a site soil profile determination extending to a depth of 100 feet for seismic site
classification. The current scope of our services does not include the required 100 foot soil profile determination. Test pits extended to
a maximum depth of 9.5 feet, and this seismic site class definition considers that similar soil continues below the maximum depth of
the subsurface exploration. Additional exploration to deeper depths would be required to confirm the conditions below the current
depth of exploration.
Liquefaction is a phenomenon where there is a reduction or complete loss of soil strength
due to an increase in water pressure induced by vibrations from a seismic event.
Liquefaction mainly affects geologically recent deposits of fine-grained sands that are
below the groundwater table. Soils of this nature derive their strength from intergranular
friction. The generated water pressure or pore pressure essentially separates the soil
grains and eliminates this intergranular friction, thus reducing or eliminating the soil’s
strength.
RGI reviewed the results of the field and laboratory testing and assessed the potential for
liquefaction of the site’s soil during an earthquake. Since the site is underlain by glacial till
and depth and lacks a shallow groundwater table, RGI considers that the possibility of
liquefaction during an earthquake is minimal.
4.6 GEOLOGIC HAZARD AREAS
Regulated geologically hazardous areas include erosion, landslide, earthquake, or other
geological hazards. Based on the definition in the Renton Municipal Code, the site does
not contain geologically hazardous areas.
Geotechnical Engineering Report 5 April 6, 2018
Jefferson and Kirkland Townhomes, Renton, Washington RGI Project No. 2018-070
5.0 Discussion and Recommendations
5.1 GEOTECHNICAL CONSIDERATIONS
Based on our study, the site is suitable for the proposed construction from a geotechnical
standpoint. Foundations for the proposed building can be supported on conventional
spread footings bearing on medium dense to dense native soil or structural fill. Slab-on-
grade floors can be similarly supported.
Detailed recommendations regarding the above issues and other geotechnical design
considerations are provided in the following sections. These recommendations should be
incorporated into the final design drawings and construction specifications.
5.2 EARTHWORK
The earthwork is expected to include excavating and backfilling the building foundations
and preparing slab subgrades.
5.2.1 EROSION AND SEDIMENT CONTROL
Potential sources or causes of erosion and sedimentation depend on construction
methods, slope length and gradient, amount of soil exposed and/or disturbed, soil type,
construction sequencing and weather. The impacts on erosion-prone areas can be
reduced by implementing an erosion and sedimentation control plan. The plan should be
designed in accordance with applicable city and/or county standards.
RGI recommends the following erosion control Best Management Practices (BMPs):
Scheduling site preparation and grading for the drier summer and early fall
months and undertaking activities that expose soil during periods of little or no
rainfall
Retaining existing vegetation whenever feasible
Establishing a quarry spall construction entrance
Installing siltation control fencing or anchored straw or coir wattles on the
downhill side of work areas
Covering soil stockpiles with anchored plastic sheeting
Revegetating or mulching exposed soils with a minimum 3-inch thickness of straw
if surfaces will be left undisturbed for more than one day during wet weather or
one week in dry weather
Directing runoff away from exposed soils and slopes
Minimizing the length and steepness of slopes with exposed soils and cover
excavation surfaces with anchored plastic sheeting
Decreasing runoff velocities with check dams, straw bales or coir wattles
Confining sediment to the project site
Geotechnical Engineering Report 6 April 6, 2018
Jefferson and Kirkland Townhomes, Renton, Washington RGI Project No. 2018-070
Inspecting and maintaining erosion and sediment control measures frequently
(The contractor should be aware that inspection and maintenance of erosion
control BMPs is critical toward their satisfactory performance. Repair and/or
replacement of dysfunctional erosion control elements should be anticipated.)
Permanent erosion protection should be provided by reestablishing vegetation using
hydroseeding and/or landscape planting. Until the permanent erosion protection is
established, site monitoring should be performed by qualified personnel to evaluate the
effectiveness of the erosion control measures. Provisions for modifications to the erosion
control system based on monitoring observations should be included in the erosion and
sedimentation control plan.
5.2.2 STRIPPING AND SUBGRADE PREPARATION
Stripping efforts should include removal of pavements, vegetation, organic materials, and
deleterious debris from areas slated for building, pavement, and utility construction. The
test pits encountered 6 to 16 inches of topsoil and rootmass. Deeper areas of stripping
may be required in forested or heavily vegetated areas of the site.
Subgrade soils that become disturbed due to elevated moisture conditions should be
overexcavated to reveal firm, non-yielding, non-organic soils and backfilled with
compacted structural fill. In order to maximize utilization of site soils as structural fill, RGI
recommends that the earthwork portion of this project be completed during extended
periods of warm and dry weather if possible. If earthwork is completed during the wet
season (typically November through May) it will be necessary to take extra precautionary
measures to protect subgrade soils. Wet season earthwork will require additional
mitigative measures beyond that which would be expected during the drier summer and
fall months.
5.2.3 EXCAVATIONS
All temporary cut slopes associated with the site and utility excavations should be
adequately inclined to prevent sloughing and collapse. The site soils consist of medium
dense to dense silty sand with trace gravel and sand with some silt and trace gravel, with
localized gravel beds.
Accordingly, for excavations more than 4 feet but less than 20 feet in depth, the
temporary side slopes should be laid back with a minimum slope inclination of 1H:1V
(Horizontal:Vertical). If there is insufficient room to complete the excavations in this
manner, or excavations greater than 20 feet in depth are planned, using temporary
shoring to support the excavations should be considered. For open cuts at the site, RGI
recommends:
No traffic, construction equipment, stockpiles or building supplies are allowed at
the top of cut slopes within a distance of at least five feet from the top of the cut
Geotechnical Engineering Report 7 April 6, 2018
Jefferson and Kirkland Townhomes, Renton, Washington RGI Project No. 2018-070
Exposed soil along the slope is protected from surface erosion using waterproof
tarps and/or plastic sheeting
Construction activities are scheduled so that the length of time the temporary cut
is left open is minimized
Surface water is diverted away from the excavation
The general condition of slopes should be observed periodically by a geotechnical
engineer to confirm adequate stability and erosion control measures
In all cases, however, appropriate inclinations will depend on the actual soil and
groundwater conditions encountered during earthwork. Ultimately, the site contractor
must be responsible for maintaining safe excavation slopes that comply with applicable
OSHA or WISHA guidelines.
5.2.4 STRUCTURAL FILL
RGI recommends fill below the foundation and floor slab, behind retaining walls, and
below pavement and hardscape surfaces be placed in accordance with the following
recommendations for structural fill. The structural fill should be placed after completion
of site preparation procedures as described above.
The suitability of excavated site soils and import soils for compacted structural fill use will
depend on the gradation and moisture content of the soil when it is placed. As the
amount of fines (that portion passing the U.S. No. 200 sieve) increases, soil becomes
increasingly sensitive to small changes in moisture content and adequate compaction
becomes more difficult or impossible to achieve. Soils containing more than about 5
percent fines cannot be consistently compacted to a dense, non-yielding condition when
the moisture content is more than 2 percent above or below optimum. Optimum
moisture content is that moisture that results in the greatest compacted dry density with
a specified compactive effort.
Non-organic site soils are only considered suitable for structural fill provided that their
moisture content is within about two percent of the optimum moisture level as
determined by ASTM D1557. Excavated site soils may not be suitable for re-use as
structural fill depending on the moisture content and weather conditions at the time of
construction. If soils are stockpiled for future reuse and wet weather is anticipated, the
stockpile should be protected with plastic sheeting that is securely anchored. Even during
dry weather, moisture conditioning (such as, windrowing and drying) of site soils to be
reused as structural fill may be required.
Some of the site soils are moisture sensitive and may require moisture conditioning prior
to use as structural fill. If on-site soils are or become unusable, it may become necessary
to import clean, granular soils to complete site work that meet the grading requirements
listed in Table 2 to be used as structural fill.
Geotechnical Engineering Report 8 April 6, 2018
Jefferson and Kirkland Townhomes, Renton, Washington RGI Project No. 2018-070
Table 2 Structural Fill Gradation
U.S. Sieve Size Percent Passing
4 inches 100
No. 4 sieve 22 to 100
No. 200 sieve 0 to 5*
*Based on minus 3/4 inch fraction.
Prior to use, an RGI representative should observe and test all materials imported to the
site for use as structural fill. Structural fill materials should be placed in uniform loose
layers not exceeding 12 inches and compacted as specified in Table 3. The soil’s maximum
density and optimum moisture should be determined by ASTM D1557.
Table 3 Structural Fill Compaction ASTM D1557
Location Material Type
Minimum
Compaction
Percentage
Moisture Content
Range
Foundations On-site granular or approved
imported fill soils: 95 +2 -2
Retaining Wall Backfill On-site granular or approved
imported fill soils: 92 +2 -2
Slab-on-grade On-site granular or approved
imported fill soils: 95 +2 -2
General Fill (non-
structural areas)
On-site soils or approved
imported fill soils: 90 +3 -2
Placement and compaction of structural fill should be observed by RGI. A representative
number of in-place density tests should be performed as the fill is being placed to confirm
that the recommended level of compaction is achieved.
5.2.5 WET WEATHER CONSTRUCTION CONSIDERATIONS
RGI recommends that preparation for site grading and construction include procedures
intended to drain ponded water, control surface water runoff, and to collect shallow
subsurface seepage zones in excavations where encountered. It will not be possible to
successfully compact the subgrade or utilize on-site soils as structural fill if accumulated
water is not drained prior to grading or if drainage is not controlled during construction.
Attempting to grade the site without adequate drainage control measures will reduce the
amount of on-site soil effectively available for use, increase the amount of select import
fill materials required, and ultimately increase the cost of the earthwork phases of the
Geotechnical Engineering Report 9 April 6, 2018
Jefferson and Kirkland Townhomes, Renton, Washington RGI Project No. 2018-070
project. Free water should not be allowed to pond on the subgrade soils. RGI anticipates
that the use of berms and shallow drainage ditches, with sumps and pumps in utility
trenches, will be required for surface water control during wet weather and/or wet site
conditions.
5.3 FOUNDATIONS
Following site preparation and grading, the proposed building foundation can be
supported on conventional spread footings bearing on medium dense to dense native soil
or structural fill. Loose, organic, or other unsuitable soils may be encountered in the
proposed building footprint. If unsuitable soils are encountered, they should be
overexcavated and backfilled with structural fill. If existing fill soils are encountered at
subgrade elevations, the suitability of the soils for foundation support should be
evaluated by a RGI representative.
Perimeter foundations exposed to weather should be at a minimum depth of 18 inches
below final exterior grades. Interior foundations can be constructed at any convenient
depth below the floor slab. Finished grade is defined as the lowest adjacent grade within
5 feet of the foundation for perimeter (or exterior) footings and finished floor level for
interior footings.
Table 4 Foundation Design
Design Parameter Value
Allowable Bearing Capacity 2,000 psf1
Friction Coefficient 0.30
Passive pressure (equivalent fluid pressure) 250 pcf2
Minimum foundation dimensions Columns: 24 inches
Walls: 16 inches
1. psf = pounds per square foot
2. pcf = pounds per cubic foot
The allowable foundation bearing pressures apply to dead loads plus design live load
conditions. For short-term loads, such as wind and seismic, a 1/3 increase in this
allowable capacity may be used. At perimeter locations, RGI recommends not including
the upper 12 inches of soil in the computation of passive pressures because they can be
affected by weather or disturbed by future grading activity. The passive pressure value
assumes the foundation will be constructed neat against competent soil or backfilled with
structural fill as described in Section 5.2.4. The recommended base friction and passive
resistance value includes a safety factor of about 1.5.
Geotechnical Engineering Report 10 April 6, 2018
Jefferson and Kirkland Townhomes, Renton, Washington RGI Project No. 2018-070
With spread footing foundations designed in accordance with the recommendations in
this section, maximum total and differential post-construction settlements of 1 inch and
1/2 inch, respectively, should be expected.
5.4 RETAINING WALLS
If retaining walls are needed in the building area or for a below grade vault, RGI
recommends cast-in-place concrete walls be used. The magnitude of earth pressure
development on retaining walls will partly depend on the quality of the wall backfill. RGI
recommends placing and compacting wall backfill as structural fill. Wall drainage will be
needed behind the wall face. A typical retaining wall drainage detail is shown in Figure 3.
With wall backfill placed and compacted as recommended, and drainage properly
installed, RGI recommends using the values in the following table for design.
Table 5 Retaining Wall Design
Design Parameter Value
Allowable Bearing Capacity 2,000 psf
Active Earth Pressure (unrestrained walls) 35 pcf
At-rest Earth Pressure (restrained walls) 50 pcf
For seismic design, an additional uniform load of 7 times the wall height (H) for
unrestrained walls and 14H in psf for restrained walls should be applied to the wall
surface. Friction at the base of foundations and passive earth pressure will provide
resistance to these lateral loads. Values for these parameters are provided in Section 5.3.
5.5 SLAB-ON-GRADE CONSTRUCTION
Once site preparation has been completed as described in Section 5.2, suitable support
for slab-on-grade construction should be provided. RGI recommends that the concrete
slab be placed on top of medium dense native soil or structural fill. Immediately below
the floor slab, RGI recommends placing a four-inch thick capillary break layer of clean,
free-draining sand or gravel that has less than five percent passing the U.S. No. 200 sieve.
This material will reduce the potential for upward capillary movement of water through
the underlying soil and subsequent wetting of the floor slab. Where moisture by vapor
transmission is undesirable, an 8- to 10-millimeter thick plastic membrane should be
placed on a 4-inch thick layer of clean gravel.
For the anticipated floor slab loading, we estimate post-construction floor settlements of
1/4- to 1/2-inch.
Geotechnical Engineering Report 11 April 6, 2018
Jefferson and Kirkland Townhomes, Renton, Washington RGI Project No. 2018-070
5.6 DRAINAGE
5.6.1 SURFACE
Final exterior grades should promote free and positive drainage away from the building
area. Water must not be allowed to pond or collect adjacent to foundations or within the
immediate building area. For non-pavement locations, RGI recommends providing a
minimum drainage gradient of 3 percent for a minimum distance of 10 feet from the
building perimeter. In paved locations, a minimum gradient of 1 percent should be
provided unless provisions are included for collection and disposal of surface water
adjacent to the structure.
5.6.2 SUBSURFACE
RGI recommends installing perimeter foundation drains. A typical footing drain detail is
shown on Figure 4. The foundation drains and roof downspouts should be tightlined
separately to an approved discharge facility. Subsurface drains must be laid with a
gradient sufficient to promote positive flow to a controlled point of approved discharge.
5.6.3 INFILTRATION
RGI understands that an infiltration system is being considered for the on-site disposal of
stormwater run-off in the central portion of the property. A field infiltration test at test
pit TP-2 was performed in general accordance with a Small-Scale Pilot Infiltration Test
described in Reference 6A – Infiltration Rate Test Methods in the King County,
Washington, Surface Water Design Manual.
Table 6 Measured Infiltration Rates
Test Location Test Depth Measured Rate
(Inches per hour)
Design Rate
(Inches per hour)
TP-2 4’ 6.5 2.6
King County Surface Water Design Manual correction factors were applied to the field
measured rate of 6.5 inches per hour. No groundwater was encountered in the test pits.
Very dense glacial till was encountered at 9 feet below grade in test pit, TP-1 and is a
restrictive layer.
Idesign = Imeasured x Ftesting x Fplugging x Fgeometry
Correction factors of 0.5 (Ftesting) for the PIT test method and 0.8 (Fplugging) for fine sands
were applied to the field measured rate to estimate the long-term design infiltration rate.
We assumed Fgeometry = 1. The application of the correction factors yield a long-term
design rate (Idesign) of 2.6 inches per hour.
Geotechnical Engineering Report 12 April 6, 2018
Jefferson and Kirkland Townhomes, Renton, Washington RGI Project No. 2018-070
5.7 UTILITIES
Utility pipes should be bedded and backfilled in accordance with American Public Works
Association (APWA) specifications. For site utilities located within the right-of-ways,
bedding and backfill should be completed in accordance with City of Renton
specifications. At a minimum, trench backfill should be placed and compacted as
structural fill, as described in Section 5.2.4. Where utilities occur below unimproved
areas, the degree of compaction can be reduced to a minimum of 90 percent of the soil’s
maximum density as determined by the referenced ASTM D1557.
6.0 Additional Services
RGI is available to provide further geotechnical consultation throughout the design phase
of the project. RGI should review the final design and specifications in order to verify that
earthwork and foundation recommendations have been properly interpreted and
incorporated into project design and construction.
RGI is also available to provide geotechnical engineering and construction monitoring
services during construction. The integrity of the earthwork and construction depends on
proper site preparation and procedures. In addition, engineering decisions may arise in
the field in the event that variations in subsurface conditions become apparent.
Construction monitoring services are not part of this scope of work. If these services are
desired, please let us know and we will prepare a cost proposal.
7.0 Limitations
This GER is the property of RGI, Anita Woo, and her designated agents. Within the limits
of the scope and budget, this GER was prepared in accordance with generally accepted
geotechnical engineering practices in the area at the time this GER was issued. This GER is
intended for specific application to the Jefferson and Kirkland Townhomes project in
Renton, Washington, and for the exclusive use of Anita Woo and her authorized
representatives. No other warranty, expressed or implied, is made. Site safety, excavation
support, and dewatering requirements are the responsibility of others.
The scope of services for this project does not include either specifically or by implication
any environmental or biological (for example, mold, fungi, bacteria) assessment of the
site or identification or prevention of pollutants, hazardous materials or conditions. If the
owner is concerned about the potential for such contamination or pollution, we can
provide a proposal for these services.
The analyses and recommendations presented in this GER are based upon data obtained
from the explorations performed on site. Variations in soil conditions can occur, the
nature and extent of which may not become evident until construction. If variations
Geotechnical Engineering Report 13 April 6, 2018
Jefferson and Kirkland Townhomes, Renton, Washington RGI Project No. 2018-070
appear evident, RGI should be requested to reevaluate the recommendations in this GER
prior to proceeding with construction.
It is the client’s responsibility to see that all parties to the project, including the designers,
contractors, subcontractors, are made aware of this GER in its entirety. The use of
information contained in this GER for bidding purposes should be done at the contractor’s
option and risk.
USGS, 2014, Mercer Island, Washington
USGS, 2014, Renton, Washington
7.5-Minute Quadrangle
Approximate Scale: 1"=1000'
0 500 1000 2000 N
Site Vicinity Map
Figure 1
04/2018
Corporate Office
17522 Bothell Way Northeast
Bothell, Washington 98011
Phone: 425.415.0551
Fax: 425.415.0311
Jefferson and Kirkland Townhomes
RGI Project Number
2018-070
Date Drawn:
Address: 1513 Kirkland Avenue Northeast & 1526 Jefferson Avenue Northeast Renton, Washington 98056
SITE
TP-1TP-2TP-3TP-4TP-504/2018Corporate Office17522 Bothell Way NortheastBothell, Washington 98011Phone: 425.415.0551Fax: 425.415.0311Jefferson and Kirkland TownhomesRGI Project Number2018-070Date Drawn:Address: 1513 Kirkland Avenue Northeast & 1526 Jefferson Avenue Northeast Renton, Washington 98056Geotechnical Exploration PlanFigure 2Approximate Scale: 1"=30'0153060N= Test pit by RGI, 3/30/18= Site boundary
Incliniations)
12" Over the Pipe
3" Below the Pipe
Perforated Pipe
4" Diameter PVC
Compacted Structural
Backfill (Native or Import)
12" min.
Filter Fabric Material
12" Minimum Wide
Free-Draining Gravel
Slope to Drain
(See Report for
Appropriate
Excavated Slope
04/2018
Corporate Office
17522 Bothell Way Northeast
Bothell, Washington 98011
Phone: 425.415.0551
Fax: 425.415.0311
Jefferson and Kirkland Townhomes
RGI Project Number
2018-070
Date Drawn:
Address: 1513 Kirkland Avenue Northeast & 1526 Jefferson Avenue Northeast Renton, Washington 98056
Retaining Wall Drainage Detail
Figure 3
Not to Scale
3/4" Washed Rock or Pea Gravel
4" Perforated Pipe
Building Slab
Structural
Backfill
Compacted
Filter Fabric
04/2018
Corporate Office
17522 Bothell Way Northeast
Bothell, Washington 98011
Phone: 425.415.0551
Fax: 425.415.0311
Jefferson and Kirkland Townhomes
RGI Project Number
2018-070
Date Drawn:
Address: 1513 Kirkland Avenue Northeast & 1526 Jefferson Avenue Northeast Renton, Washington 98056
Typical Footing Drain Detail
Figure 4
Not to Scale
Geotechnical Engineering Report April 6, 2018
Jefferson and Kirkland Townhomes, Renton, Washington RGI Project No. 2018-070
APPENDIX A
FIELD EXPLORATION AND LABORATORY TESTING
On March 30, RGI performed field explorations using a rubber tracked excavator. We
explored subsurface soil conditions at the site by observing the excavation of five test pits
to a maximum depth of 9.5 feet below existing grade. The test pit locations are shown on
Figure 2. The test pit locations were approximately determined by measurements from
existing property lines and paved roads.
A geologist from our office conducted the field exploration and classified the soil
conditions encountered, maintained a log of each test exploration, obtained
representative soil samples, and observed pertinent site features. All soil samples were
visually classified in accordance with the Unified Soil Classification System (USCS).
Representative soil samples obtained from the explorations were placed in closed
containers and taken to our laboratory for further examination and testing. As a part of
the laboratory testing program, the soil samples were classified in our in house laboratory
based on visual observation, texture, plasticity, and the limited laboratory testing
described below.
Moisture Content Determinations
Moisture content determinations were performed in accordance with ASTM D2216-10
Standard Test Methods for Laboratory Determination of Water (Moisture) Content of Soil
and Rock by Mass (ASTM D2216) on representative samples obtained from the
exploration in order to aid in identification and correlation of soil types. The moisture
content of typical sample was measured and is reported on the test pit logs.
Grain Size Analysis
A grain size analysis indicates the range in diameter of soil particles included in a
particular sample. Grain size analyses was determined using D6913-04(2009) Standard
Test Methods for Particle-Size Distribution (Gradation) of Soils Using Sieve Analysis (ASTM
D6913) on seven of the samples.
Project Name:Jefferson Highlands Townhomes
Project Number:2018-070
Client:Anita Woo
Test Pit No.: TP-1
Date(s) Excavated:3/30/2018
Excavation Method:Trackhoe
Excavator Type:Rubber Tracked Excavator
Groundwater Level:Not Encountered
Test Pit Backfill:Cuttings
Logged By ELW
Bucket Size:N/A
Excavating Contractor:Ryatt Construction
Sampling
Method(s)Grab
Location 1513 Kirkland Avenue NE & 1526 Jefferson Avenue NE, Renton, Washington
Surface Conditions:Grass
Total Depth of Excavation:9.5 feet bgs
Approximate
Surface Elevation N/A
Compaction Method Bucket
USCS SymbolTPSL
SM
GP
SP-SM
SM
SM
REMARKS AND OTHER TESTS
12% moisture
4% moisture, 1% fines
7% moisture, 10% fines
8% moisture, 15% fines
13% moistureGraphic LogMATERIAL DESCRIPTION
16" topsoil
Reddish brown silty SAND with trace gravel, loose to
medium dense, moist
Gray GRAVEL with some sand and trace silt, medium
dense, moist
Gray SAND with some silt and trace gravel, medium dense,
moist
Contains roots
Localized iron oxide staining
Gray silty SAND with trace gravel, dense, moist
Gray silty SAND with some gravel, very dense, moist
(Glacial Till)
Test Pit terminated at 9.5'Depth (feet)0
5
10 Sample NumberSample TypeElevation (feet)Sheet 1 of 1
The Riley Group, Inc.
17522 Bothell Way NE, Bothell, WA 98011
Project Name:Jefferson Highlands Townhomes
Project Number:2018-070
Client:Anita Woo
Test Pit No.: TP-2
Date(s) Excavated:3/30/2018
Excavation Method:Trackhoe
Excavator Type:Rubber Tracked Excavator
Groundwater Level:Not Encountered
Test Pit Backfill:Cuttings
Logged By ELW
Bucket Size:N/A
Excavating Contractor:Ryatt Construction
Sampling
Method(s)Grab
Location 1513 Kirkland Avenue NE & 1526 Jefferson Avenue NE, Renton, Washington
Surface Conditions:Grass
Total Depth of Excavation:6.5 feet bgs
Approximate
Surface Elevation N/A
Compaction Method Bucket
USCS SymbolTPSL
SM
GP
SP-SM
SM
REMARKS AND OTHER TESTS
3% moisture, 1% fines
9% moisture, 11% fines
15% moisture, 14% fines
12% moisture, 14% finesGraphic LogMATERIAL DESCRIPTION
12" topsoil
Reddish brown silty SAND with trace gravel, loose to
medium dense, moist
Gray GRAVEL with some sand and trace silt, medium
dense, moist
Gray SAND with some silt and trace gravel, medium dense,
moist
Infiltration test at 4'
Gray silty SAND with trace gravel, dense, wet
Iron oxide staining
Becomes moist to wet
Test Pit terminated at 6.5'Depth (feet)0
5
10 Sample NumberSample TypeElevation (feet)Sheet 1 of 1
The Riley Group, Inc.
17522 Bothell Way NE, Bothell, WA 98011
Project Name:Jefferson Highlands Townhomes
Project Number:2018-070
Client:Anita Woo
Test Pit No.: TP-3
Date(s) Excavated:3/30/2018
Excavation Method:Trackhoe
Excavator Type:Rubber Tracked Excavator
Groundwater Level:Not Encountered
Test Pit Backfill:Cuttings
Logged By ELW
Bucket Size:N/A
Excavating Contractor:Ryatt Construction
Sampling
Method(s)Grab
Location 1513 Kirkland Avenue NE & 1526 Jefferson Avenue NE, Renton, Washington
Surface Conditions:Grass
Total Depth of Excavation:5 feet bgs
Approximate
Surface Elevation N/A
Compaction Method Bucket
USCS SymbolTPSL
SM
SP-SM
REMARKS AND OTHER TESTS
14% moisture
7% moisture
7% moistureGraphic LogMATERIAL DESCRIPTION
12" topsoil
Reddish brown silty SAND with trace gravel, loose to
medium dense, moist
Gray SAND with some silt and trace gravel, medium dense,
moist
Test Pit terminated at 5'Depth (feet)0
5
10 Sample NumberSample TypeElevation (feet)Sheet 1 of 1
The Riley Group, Inc.
17522 Bothell Way NE, Bothell, WA 98011
Project Name:Jefferson Highlands Townhomes
Project Number:2018-070
Client:Anita Woo
Test Pit No.: TP-4
Date(s) Excavated:3/30/2018
Excavation Method:Trackhoe
Excavator Type:Rubber Tracked Excavator
Groundwater Level:Not Encountered
Test Pit Backfill:Cuttings
Logged By ELW
Bucket Size:N/A
Excavating Contractor:Ryatt Construction
Sampling
Method(s)Grab
Location 1513 Kirkland Avenue NE & 1526 Jefferson Avenue NE, Renton, Washington
Surface Conditions:Grass
Total Depth of Excavation:5.5 feet bgs
Approximate
Surface Elevation N/A
Compaction Method Bucket
USCS SymbolTPSL
Fill
SM
SP-SM
SM
REMARKS AND OTHER TESTS
17% moisture
9% moisture
12% moistureGraphic LogMATERIAL DESCRIPTION
6" topsoil
Brown silty SAND with trace gravel, loose, moist (Fill)
Contains brick debris
Reddish brown silty SAND with trace gravel, loose to
medium dense, moist
Gray SAND with some silt and trace gravel, medium dense,
moist
Gray silty SAND with trace gravel, medium dense, moist
Trace iron oxide stasining
Test Pit terminated at 5.5'Depth (feet)0
5
10 Sample NumberSample TypeElevation (feet)Sheet 1 of 1
The Riley Group, Inc.
17522 Bothell Way NE, Bothell, WA 98011
Project Name:Jefferson Highlands Townhomes
Project Number:2018-070
Client:Anita Woo
Test Pit No.: TP-5
Date(s) Excavated:3/30/2018
Excavation Method:Trackhoe
Excavator Type:Rubber Tracked Excavator
Groundwater Level:Not Encountered
Test Pit Backfill:Cuttings
Logged By ELW
Bucket Size:N/A
Excavating Contractor:Ryatt Construction
Sampling
Method(s)Grab
Location 1513 Kirkland Avenue NE & 1526 Jefferson Avenue NE, Renton, Washington
Surface Conditions:Grass
Total Depth of Excavation:6.5 feet bgs
Approximate
Surface Elevation N/A
Compaction Method Bucket
USCS SymbolTPSL
Fill
Fill
TPSL
SM
SP-SM
REMARKS AND OTHER TESTS
10% moisture
13% moisture
8% moistureGraphic LogMATERIAL DESCRIPTION
6" topsoil
Brown silty SAND with trace gravel, medium dense, moist
(Fill)
Contains brick and metal debris
Gray SAND with some silt and trace gravel, medium dense,
moist (Fill)
6" topsoil
Reddish brown silty SAND with trace gravel, medium
dense, moist
Gray SAND with some silt and trace gravel, medium dense,
moist
Test Pit terminated at 6.5'Depth (feet)0
5
10 Sample NumberSample TypeElevation (feet)Sheet 1 of 1
The Riley Group, Inc.
17522 Bothell Way NE, Bothell, WA 98011
Project Name:Jefferson Highlands Townhomes
Project Number:2018-070
Client:Anita Woo
Key to Logs
USCS SymbolREMARKS AND OTHER TESTSGraphic LogMATERIAL DESCRIPTIONDepth (feet)Sample NumberSample TypeElevation (feet)1 2 3 4 5 6 7 8
COLUMN DESCRIPTIONS
1 Elevation (feet): Elevation (MSL, feet).
2 Depth (feet): Depth in feet below the ground surface.
3 Sample Type: Type of soil sample collected at the depth interval
shown.
4 Sample Number: Sample identification number.
5 USCS Symbol: USCS symbol of the subsurface material.
6 Graphic Log: Graphic depiction of the subsurface material
encountered.
7 MATERIAL DESCRIPTION: Description of material encountered.
May include consistency, moisture, color, and other descriptive
text.
8 REMARKS AND OTHER TESTS: Comments and observations
regarding drilling or sampling made by driller or field personnel.
FIELD AND LABORATORY TEST ABBREVIATIONS
CHEM: Chemical tests to assess corrosivity
COMP: Compaction test
CONS: One-dimensional consolidation test
LL: Liquid Limit, percent
PI: Plasticity Index, percent
SA: Sieve analysis (percent passing No. 200 Sieve)
UC: Unconfined compressive strength test, Qu, in ksf
WA: Wash sieve (percent passing No. 200 Sieve)
MATERIAL GRAPHIC SYMBOLS
AF
Poorly graded GRAVEL (GP)
Silty SAND (SM)
Poorly graded SAND with Silt (SP-SM)
Topsoil
TYPICAL SAMPLER GRAPHIC SYMBOLS
Auger sampler
Bulk Sample
3-inch-OD California w/
brass rings
CME Sampler
Grab Sample
2.5-inch-OD Modified
California w/ brass liners
Pitcher Sample
2-inch-OD unlined split
spoon (SPT)
Shelby Tube (Thin-walled,
fixed head)
OTHER GRAPHIC SYMBOLS
Water level (at time of drilling, ATD)
Water level (after waiting)
Minor change in material properties within a
stratum
Inferred/gradational contact between strata
?Queried contact between strata
GENERAL NOTES
1: Soil classifications are based on the Unified Soil Classification System. Descriptions and stratum lines are interpretive, and actual lithologic changes may be
gradual. Field descriptions may have been modified to reflect results of lab tests.
2: Descriptions on these logs apply only at the specific boring locations and at the time the borings were advanced. They are not warranted to be representative
of subsurface conditions at other locations or times.
Sheet 1 of 1
The Riley Group, Inc.
17522 Bothell Way NE, Bothell, WA 98011
THE RILEY GROUP, INC.
17522 Bothell Way NE
Bothell, WA 98011
PHONE: (425) 415-0551
FAX: (425) 415-0311
GRAIN SIZE ANALYSIS
ASTM D421, D422, D1140, D2487, D6913
PROJECT TITLE Jefferson Highlands Townhomes SAMPLE ID/TYPE TP-1
PROJECT NO.2018-070 SAMPLE DEPTH 2.5'
TECH/TEST DATE ELW 3/31/2018 DATE RECEIVED 3/30/2018
WATER CONTENT (Delivered Moisture) Total Weight Of Sample Used For Sieve Corrected For Hygroscopic Moisture
Wt Wet Soil & Tare (gm) (w1)666.3 Weight Of Sample (gm)641.7
Wt Dry Soil & Tare (gm)(w2)641.7 Tare Weight (gm) 15.4
Weight of Tare (gm)(w3)15.4 (W6) Total Dry Weight (gm)626.3
Weight of Water (gm)(w4=w1-w2)24.6 SIEVE ANALYSIS
Weight of Dry Soil (gm) (w5=w2-w3)626.3 Cumulative
Moisture Content (%) (w4/w5)*100 4 Wt Ret (Wt-Tare) (%Retained)% PASS
+Tare {(wt ret/w6)*100}(100-%ret)
% COBBLES 0.0 12.0"15.4 0.00 0.00 100.00 cobbles
% C GRAVEL 58.2 3.0"15.4 0.00 0.00 100.00 coarse gravel
% F GRAVEL 14.8 2.5" coarse gravel
% C SAND 2.6 2.0" coarse gravel
% M SAND 14.5 1.5"15.4 0.00 0.00 100.00 coarse gravel
% F SAND 9.0 1.0" coarse gravel
% FINES 1.0 0.75"379.8 364.40 58.18 41.82 fine gravel
% TOTAL 100.0 0.50" fine gravel
0.375"457.7 442.30 70.62 29.38 fine gravel
D10 (mm)0.41 #4 472.6 457.20 73.00 27.00 coarse sand
D30 (mm)9.5 #10 488.6 473.20 75.55 24.45 medium sand
D60 (mm)23 #20 medium sand
Cu 56.1 #40 579.4 564.00 90.05 9.95 fine sand
Cc 9.6 #60 fine sand
#100 630.3 614.90 98.18 1.82 fine sand
#200 635.6 620.20 99.03 0.97 fines
PAN 641.7 626.30 100.00 0.00 silt/clay
322
DESCRIPTION GRAVEL with some sand and trace silt
USCS GP
Prepared For:Reviewed By:
Anita Woo KMW
0
10
20
30
40
50
60
70
80
90
100
0.0010.010.11101001000
%
P
A
S
S
I
N
G
Grain size in millimeters
12"3"2"1".75".375"#4 #10 #20 #40 #60 #100 #200
THE RILEY GROUP, INC.
17522 Bothell Way NE
Bothell, WA 98011
PHONE: (425) 415-0551
FAX: (425) 415-0311
GRAIN SIZE ANALYSIS
ASTM D421, D422, D1140, D2487, D6913
PROJECT TITLE Jefferson Highlands Townhomes SAMPLE ID/TYPE TP-1
PROJECT NO.2018-070 SAMPLE DEPTH 4'
TECH/TEST DATE ELW 3/31/2018 DATE RECEIVED 3/30/2018
WATER CONTENT (Delivered Moisture) Total Weight Of Sample Used For Sieve Corrected For Hygroscopic Moisture
Wt Wet Soil & Tare (gm) (w1)371.4 Weight Of Sample (gm)347.4
Wt Dry Soil & Tare (gm)(w2)347.4 Tare Weight (gm) 15.6
Weight of Tare (gm)(w3)15.6 (W6) Total Dry Weight (gm)331.8
Weight of Water (gm)(w4=w1-w2)24.0 SIEVE ANALYSIS
Weight of Dry Soil (gm) (w5=w2-w3)331.8 Cumulative
Moisture Content (%) (w4/w5)*100 7 Wt Ret (Wt-Tare) (%Retained)% PASS
+Tare {(wt ret/w6)*100}(100-%ret)
% COBBLES 0.0 12.0"15.6 0.00 0.00 100.00 cobbles
% C GRAVEL 0.0 3.0"15.6 0.00 0.00 100.00 coarse gravel
% F GRAVEL 6.7 2.5" coarse gravel
% C SAND 4.2 2.0" coarse gravel
% M SAND 26.8 1.5"15.6 0.00 0.00 100.00 coarse gravel
% F SAND 52.0 1.0" coarse gravel
% FINES 10.2 0.75"15.6 0.00 0.00 100.00 fine gravel
% TOTAL 100.0 0.50" fine gravel
0.375"26.3 10.70 3.22 96.78 fine gravel
D10 (mm)0.075 #4 37.9 22.30 6.72 93.28 coarse sand
D30 (mm)0.2 #10 51.9 36.30 10.94 89.06 medium sand
D60 (mm)0.4 #20 medium sand
Cu 5.3 #40 140.9 125.30 37.76 62.24 fine sand
Cc 1.3 #60 fine sand
#100 288.0 272.40 82.10 17.90 fine sand
#200 313.5 297.90 89.78 10.22 fines
PAN 347.4 331.80 100.00 0.00 silt/clay
322
DESCRIPTION SAND with some silt and trace gravel
USCS SP-SM
Prepared For:Reviewed By:
Anita Woo KMW
0
10
20
30
40
50
60
70
80
90
100
0.0010.010.11101001000
%
P
A
S
S
I
N
G
Grain size in millimeters
12"3"2"1".75".375"#4 #10 #20 #40 #60 #100 #200
THE RILEY GROUP, INC.
17522 Bothell Way NE
Bothell, WA 98011
PHONE: (425) 415-0551
FAX: (425) 415-0311
GRAIN SIZE ANALYSIS
ASTM D421, D422, D1140, D2487, D6913
PROJECT TITLE Jefferson Highlands Townhomes SAMPLE ID/TYPE TP-1
PROJECT NO.2018-070 SAMPLE DEPTH 6.5'
TECH/TEST DATE ELW 3/31/2018 DATE RECEIVED 3/30/2018
WATER CONTENT (Delivered Moisture) Total Weight Of Sample Used For Sieve Corrected For Hygroscopic Moisture
Wt Wet Soil & Tare (gm) (w1)490.6 Weight Of Sample (gm)454.9
Wt Dry Soil & Tare (gm)(w2)454.9 Tare Weight (gm) 15.4
Weight of Tare (gm)(w3)15.4 (W6) Total Dry Weight (gm)439.5
Weight of Water (gm)(w4=w1-w2)35.7 SIEVE ANALYSIS
Weight of Dry Soil (gm) (w5=w2-w3)439.5 Cumulative
Moisture Content (%) (w4/w5)*100 8 Wt Ret (Wt-Tare) (%Retained)% PASS
+Tare {(wt ret/w6)*100}(100-%ret)
% COBBLES 0.0 12.0"15.4 0.00 0.00 100.00 cobbles
% C GRAVEL 5.1 3.0"15.4 0.00 0.00 100.00 coarse gravel
% F GRAVEL 7.6 2.5" coarse gravel
% C SAND 2.4 2.0" coarse gravel
% M SAND 19.2 1.5"15.4 0.00 0.00 100.00 coarse gravel
% F SAND 50.9 1.0" coarse gravel
% FINES 14.9 0.75"37.9 22.50 5.12 94.88 fine gravel
% TOTAL 100.0 0.50" fine gravel
0.375"65.9 50.50 11.49 88.51 fine gravel
D10 (mm)#4 71.1 55.70 12.67 87.33 coarse sand
D30 (mm)#10 81.6 66.20 15.06 84.94 medium sand
D60 (mm)#20 medium sand
Cu #40 165.8 150.40 34.22 65.78 fine sand
Cc #60 fine sand
#100 349.2 333.80 75.95 24.05 fine sand
#200 389.3 373.90 85.07 14.93 fines
PAN 454.9 439.50 100.00 0.00 silt/clay
322
DESCRIPTION Silty SAND with trace gravel
USCS SM
Prepared For:Reviewed By:
Anita Woo KMW
0
10
20
30
40
50
60
70
80
90
100
0.0010.010.11101001000
%
P
A
S
S
I
N
G
Grain size in millimeters
12"3"2"1".75".375"#4 #10 #20 #40 #60 #100 #200
THE RILEY GROUP, INC.
17522 Bothell Way NE
Bothell, WA 98011
PHONE: (425) 415-0551
FAX: (425) 415-0311
GRAIN SIZE ANALYSIS
ASTM D421, D422, D1140, D2487, D6913
PROJECT TITLE Jefferson Highlands Townhomes SAMPLE ID/TYPE TP-2
PROJECT NO.2018-070 SAMPLE DEPTH 3'
TECH/TEST DATE ELW 3/31/2018 DATE RECEIVED 3/30/2018
WATER CONTENT (Delivered Moisture) Total Weight Of Sample Used For Sieve Corrected For Hygroscopic Moisture
Wt Wet Soil & Tare (gm) (w1)884.5 Weight Of Sample (gm)860.6
Wt Dry Soil & Tare (gm)(w2)860.6 Tare Weight (gm) 15.4
Weight of Tare (gm)(w3)15.4 (W6) Total Dry Weight (gm)845.2
Weight of Water (gm)(w4=w1-w2)23.9 SIEVE ANALYSIS
Weight of Dry Soil (gm) (w5=w2-w3)845.2 Cumulative
Moisture Content (%) (w4/w5)*100 3 Wt Ret (Wt-Tare) (%Retained)% PASS
+Tare {(wt ret/w6)*100}(100-%ret)
% COBBLES 0.0 12.0"15.4 0.00 0.00 100.00 cobbles
% C GRAVEL 61.0 3.0"15.4 0.00 0.00 100.00 coarse gravel
% F GRAVEL 17.8 2.5" coarse gravel
% C SAND 3.5 2.0" coarse gravel
% M SAND 12.1 1.5"15.4 0.00 0.00 100.00 coarse gravel
% F SAND 4.9 1.0" coarse gravel
% FINES 0.7 0.75"531.0 515.60 61.00 39.00 fine gravel
% TOTAL 100.0 0.50" fine gravel
0.375"641.6 626.20 74.09 25.91 fine gravel
D10 (mm)0.7 #4 681.7 666.30 78.83 21.17 coarse sand
D30 (mm)12 #10 711.0 695.60 82.30 17.70 medium sand
D60 (mm)24 #20 medium sand
Cu 34.3 #40 813.2 797.80 94.39 5.61 fine sand
Cc 8.6 #60 fine sand
#100 850.4 835.00 98.79 1.21 fine sand
#200 854.7 839.30 99.30 0.70 fines
PAN 860.6 845.20 100.00 0.00 silt/clay
322
DESCRIPTION GRAVEL with some sand and trace silt
USCS GP
Prepared For:Reviewed By:
Anita Woo KMW
0
10
20
30
40
50
60
70
80
90
100
0.0010.010.11101001000
%
P
A
S
S
I
N
G
Grain size in millimeters
12"3"2"1".75".375"#4 #10 #20 #40 #60 #100 #200
THE RILEY GROUP, INC.
17522 Bothell Way NE
Bothell, WA 98011
PHONE: (425) 415-0551
FAX: (425) 415-0311
GRAIN SIZE ANALYSIS
ASTM D421, D422, D1140, D2487, D6913
PROJECT TITLE Jefferson Highlands Townhomes SAMPLE ID/TYPE TP-2
PROJECT NO.2018-070 SAMPLE DEPTH 4'
TECH/TEST DATE ELW 3/31/2018 DATE RECEIVED 3/30/2018
WATER CONTENT (Delivered Moisture) Total Weight Of Sample Used For Sieve Corrected For Hygroscopic Moisture
Wt Wet Soil & Tare (gm) (w1)335.3 Weight Of Sample (gm)308.8
Wt Dry Soil & Tare (gm)(w2)308.8 Tare Weight (gm) 15.4
Weight of Tare (gm)(w3)15.4 (W6) Total Dry Weight (gm)293.4
Weight of Water (gm)(w4=w1-w2)26.5 SIEVE ANALYSIS
Weight of Dry Soil (gm) (w5=w2-w3)293.4 Cumulative
Moisture Content (%) (w4/w5)*100 9 Wt Ret (Wt-Tare) (%Retained)% PASS
+Tare {(wt ret/w6)*100}(100-%ret)
% COBBLES 0.0 12.0"15.4 0.00 0.00 100.00 cobbles
% C GRAVEL 0.0 3.0"15.4 0.00 0.00 100.00 coarse gravel
% F GRAVEL 9.6 2.5" coarse gravel
% C SAND 5.2 2.0" coarse gravel
% M SAND 21.0 1.5"15.4 0.00 0.00 100.00 coarse gravel
% F SAND 53.1 1.0" coarse gravel
% FINES 11.1 0.75"15.4 0.00 0.00 100.00 fine gravel
% TOTAL 100.0 0.50" fine gravel
0.375"27.9 12.50 4.26 95.74 fine gravel
D10 (mm)0.07 #4 43.7 28.30 9.65 90.35 coarse sand
D30 (mm)0.19 #10 58.9 43.50 14.83 85.17 medium sand
D60 (mm)0.39 #20 medium sand
Cu 5.6 #40 120.6 105.20 35.86 64.14 fine sand
Cc 1.3 #60 fine sand
#100 249.7 234.30 79.86 20.14 fine sand
#200 276.3 260.90 88.92 11.08 fines
PAN 308.8 293.40 100.00 0.00 silt/clay
322
DESCRIPTION SAND with some silt and trace gravel
USCS SP-SM
Prepared For:Reviewed By:
Anita Woo KMW
0
10
20
30
40
50
60
70
80
90
100
0.0010.010.11101001000
%
P
A
S
S
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N
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Grain size in millimeters
12"3"2"1".75".375"#4 #10 #20 #40 #60 #100 #200
THE RILEY GROUP, INC.
17522 Bothell Way NE
Bothell, WA 98011
PHONE: (425) 415-0551
FAX: (425) 415-0311
GRAIN SIZE ANALYSIS
ASTM D421, D422, D1140, D2487, D6913
PROJECT TITLE Jefferson Highlands Townhomes SAMPLE ID/TYPE TP-2
PROJECT NO.2018-070 SAMPLE DEPTH 5'
TECH/TEST DATE ELW 3/31/2018 DATE RECEIVED 3/30/2018
WATER CONTENT (Delivered Moisture) Total Weight Of Sample Used For Sieve Corrected For Hygroscopic Moisture
Wt Wet Soil & Tare (gm) (w1)499.0 Weight Of Sample (gm)435.6
Wt Dry Soil & Tare (gm)(w2)435.6 Tare Weight (gm) 15.4
Weight of Tare (gm)(w3)15.4 (W6) Total Dry Weight (gm)420.2
Weight of Water (gm)(w4=w1-w2)63.4 SIEVE ANALYSIS
Weight of Dry Soil (gm) (w5=w2-w3)420.2 Cumulative
Moisture Content (%) (w4/w5)*100 15 Wt Ret (Wt-Tare) (%Retained)% PASS
+Tare {(wt ret/w6)*100}(100-%ret)
% COBBLES 0.0 12.0"15.4 0.00 0.00 100.00 cobbles
% C GRAVEL 0.0 3.0"15.4 0.00 0.00 100.00 coarse gravel
% F GRAVEL 10.6 2.5" coarse gravel
% C SAND 4.9 2.0" coarse gravel
% M SAND 21.8 1.5"15.4 0.00 0.00 100.00 coarse gravel
% F SAND 48.6 1.0" coarse gravel
% FINES 14.1 0.75"15.4 0.00 0.00 100.00 fine gravel
% TOTAL 100.0 0.50" fine gravel
0.375"33.4 18.00 4.28 95.72 fine gravel
D10 (mm)#4 60.1 44.70 10.64 89.36 coarse sand
D30 (mm)#10 80.7 65.30 15.54 84.46 medium sand
D60 (mm)#20 medium sand
Cu #40 172.3 156.90 37.34 62.66 fine sand
Cc #60 fine sand
#100 340.7 325.30 77.42 22.58 fine sand
#200 376.4 361.00 85.91 14.09 fines
PAN 435.6 420.20 100.00 0.00 silt/clay
322
DESCRIPTION Silty SAND with trace gravel
USCS SM
Prepared For:Reviewed By:
Anita Woo KMW
0
10
20
30
40
50
60
70
80
90
100
0.0010.010.11101001000
%
P
A
S
S
I
N
G
Grain size in millimeters
12"3"2"1".75".375"#4 #10 #20 #40 #60 #100 #200
THE RILEY GROUP, INC.
17522 Bothell Way NE
Bothell, WA 98011
PHONE: (425) 415-0551
FAX: (425) 415-0311
GRAIN SIZE ANALYSIS
ASTM D421, D422, D1140, D2487, D6913
PROJECT TITLE Jefferson Highlands Townhomes SAMPLE ID/TYPE TP-2
PROJECT NO.2018-070 SAMPLE DEPTH 6'
TECH/TEST DATE ELW 3/31/2018 DATE RECEIVED 3/30/2018
WATER CONTENT (Delivered Moisture) Total Weight Of Sample Used For Sieve Corrected For Hygroscopic Moisture
Wt Wet Soil & Tare (gm) (w1)384.0 Weight Of Sample (gm)343.2
Wt Dry Soil & Tare (gm)(w2)343.2 Tare Weight (gm) 15.5
Weight of Tare (gm)(w3)15.5 (W6) Total Dry Weight (gm)327.7
Weight of Water (gm)(w4=w1-w2)40.8 SIEVE ANALYSIS
Weight of Dry Soil (gm) (w5=w2-w3)327.7 Cumulative
Moisture Content (%) (w4/w5)*100 12 Wt Ret (Wt-Tare) (%Retained)% PASS
+Tare {(wt ret/w6)*100}(100-%ret)
% COBBLES 0.0 12.0"15.5 0.00 0.00 100.00 cobbles
% C GRAVEL 0.0 3.0"15.5 0.00 0.00 100.00 coarse gravel
% F GRAVEL 10.5 2.5" coarse gravel
% C SAND 5.5 2.0" coarse gravel
% M SAND 24.4 1.5"15.5 0.00 0.00 100.00 coarse gravel
% F SAND 45.7 1.0" coarse gravel
% FINES 13.9 0.75"15.5 0.00 0.00 100.00 fine gravel
% TOTAL 100.0 0.50" fine gravel
0.375"34.5 19.00 5.80 94.20 fine gravel
D10 (mm)#4 49.9 34.40 10.50 89.50 coarse sand
D30 (mm)#10 68.0 52.50 16.02 83.98 medium sand
D60 (mm)#20 medium sand
Cu #40 148.1 132.60 40.46 59.54 fine sand
Cc #60 fine sand
#100 272.1 256.60 78.30 21.70 fine sand
#200 297.8 282.30 86.15 13.85 fines
PAN 343.2 327.70 100.00 0.00 silt/clay
322
DESCRIPTION Silty SAND with trace gravel
USCS SM
Prepared For:Reviewed By:
Anita Woo KMW
0
10
20
30
40
50
60
70
80
90
100
0.0010.010.11101001000
%
P
A
S
S
I
N
G
Grain size in millimeters
12"3"2"1".75".375"#4 #10 #20 #40 #60 #100 #200