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GEOTECHNICAL ENGINEERING REPORT
PREPARED BY:
THE RILEY GROUP, INC.
17522 BOTHELL WAY NORTHEAST
BOTHELL, WASHINGTON 98011
PREPARED FOR:
NORDIC RIDGE, LLC
15 LAKE BELLEVUE DRIVE, SUITE 102
BELLEVUE, WASHINGTON 98005
RGI PROJECT NO. 2015-097
NORDIC RIDGE PLAT
17709 116TH AVENUE SOUTHEAST
RENTON, WASHINGTON
JULY 8, 2015
Geotechnical Engineering Report i July 8, 2015
Nordic Ridge Plat, Renton, Washington RGI Project No. 2015-097
TABLE OF CONTENTS
1.0 INTRODUCTION ............................................................................................................................... 1
2.0 PROJECT DESCRIPTION ............................................................................................................... 1
3.0 FIELD EXPLORATION AND LABORATORY TESTING .......................................................... 1
3.1 FIELD EXPLORATION ................................................................................................................................... 1
3.2 LABORATORY TESTING ................................................................................................................................ 2
4.0 SITE CONDITIONS ........................................................................................................................... 2
4.1 SURFACE .................................................................................................................................................. 2
4.2 GEOLOGY ................................................................................................................................................. 2
4.3 SOILS ....................................................................................................................................................... 2
4.4 GROUNDWATER ........................................................................................................................................ 3
4.5 SEISMIC CONSIDERATIONS ........................................................................................................................... 3
4.6 GEOLOGIC HAZARD AREAS .......................................................................................................................... 4
5.0 DISCUSSION AND RECOMMENDATIONS ................................................................................. 4
5.1 GEOTECHNICAL CONSIDERATIONS ................................................................................................................. 4
5.2 EARTHWORK ............................................................................................................................................. 4
5.2.1 Erosion and Sediment Control ..................................................................................................... 4
5.2.2 Stripping ....................................................................................................................................... 5
5.2.3 Excavations................................................................................................................................... 6
5.2.4 Site Preparation ........................................................................................................................... 6
5.2.5 Structural Fill ................................................................................................................................ 7
5.2.6 Cut and Fill Slopes ........................................................................................................................ 9
5.2.7 Wet Weather Construction Considerations ................................................................................. 9
5.3 FOUNDATIONS .......................................................................................................................................... 9
5.4 RETAINING WALLS ................................................................................................................................... 10
5.4.1 Cast-In-Place Walls ..................................................................................................................... 10
5.5 SLAB-ON-GRADE CONSTRUCTION ............................................................................................................... 11
5.6 DRAINAGE .............................................................................................................................................. 11
5.6.1 Surface ....................................................................................................................................... 11
5.6.2 Subsurface .................................................................................................................................. 12
5.6.3 Infiltration .................................................................................................................................. 12
5.7 UTILITIES ................................................................................................................................................ 12
5.8 PAVEMENTS ............................................................................................................................................ 12
6.0 ADDITIONAL SERVICES .............................................................................................................. 13
7.0 LIMITATIONS ................................................................................................................................. 13
LIST OF FIGURES AND APPENDICES
Figure 1 ..................................................................................................................... Site Vicinity Map
Figure 2 ................................................................................................ Geotechnical Exploration Plan
Figure 3 .................................................................................. Typical Retaining Wall Drainage Detail
Figure 4 ................................................................................................... Typical Footing Drain Detail
Appendix A .......................................................................... Field Exploration and Laboratory Testing
Geotechnical Engineering Report ii July 8, 2015
Nordic Ridge Plat, Renton, Washington RGI Project No. 2015-097
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 eight test pits to
approximate depths of six to eight 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 very
dense silty sand with gravel.
Groundwater: No groundwater seepage was encountered during our subsurface
exploration. However, iron oxide staining was observed at 3 to 4 feet indicating a perched
seasonal groundwater table over the top of dense glacial till layer.
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.
Pavements: The following pavement sections are recommended in accordance with the
preferred section in the King County Road Design and Construction Standards - 2007:
For Residential Streets: 2 inches of Class ½ inch Hot Mix Asphalt (HMA) over 4
inches of Class ¾ or 1 inch HMA
Geotechnical Engineering Report 1 July 8, 2015
Nordic Ridge Plat, Renton, Washington RGI Project No. 2015-097
1.0 Introduction
This Geotechnical Engineering Report (GER) presents the results of the geotechnical
engineering services provided for the Nordic Ridge Plat in Renton, King County,
Washington. The purpose of this evaluation is to assess subsurface conditions and
provide geotechnical recommendations for the construction of a residential plat. 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 17709 116th Avenue Southeast in Renton, Washington. The
approximate location of the site is shown on Figure 1.
The site is currently occupied by a single family residence with outbuildings and pasture
areas. We understand it is proposed to construct a residential development on the site
with access roadways, underground utilities and storm water facilities.
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 residences
will be supported on perimeter walls with bearing loads of two to four kips per linear
foot, and a series of columns with a maximum load up to 70 kips. Slab-on-grade floor
loading of 250 pounds per square foot (psf) are expected.
3.0 Field Exploration and Laboratory Testing
3.1 FIELD EXPLORATION
On July 1, 2015, RGI observed the excavation of eight test pits. 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 drilling 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
Geotechnical Engineering Report 2 July 8, 2015
Nordic Ridge Plat, Renton, Washington RGI Project No. 2015-097
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 an irregular-shaped parcel of land approximately 3.63 acres in size. The
site is bound to the north by Southeast Petrovitsky Road and residential property, to the
east by 116th Avenue Southeast and residential property, to the south by residential
property, and to the west by Southeast 177th Place and residential property.
The site contains a single-family residence and several out-buildings in the central portion
of the property, with the remainder of the site vegetated by grass. Several medium-
diameter trees are located around the residence and in the southern portion of the
property. Small-diameter trees ring a fenced off pasture in the northern portion of the
site. The site slopes generally northeast at gradients of about 10 percent with an
elevation change across the site of approximately 30 feet.
4.2 GEOLOGY
Review of the Geologic Map of the Renton Quadrangle, King County, Washington, by D. R.
Mullineaux (1965) indicates that the soil in the project vicinity is mapped as Ground
moraine deposits (Qgt), which is light to dark gray, nonsorted, nonstratified mixture of
clay, silt, sand, and gravel deposited by glacial ice. The deposit is generally very stiff and
impermeable, often resulting in poorly drained bogs developing in relatively flat area. The
deposit is usually 1 to 2 meters thick, but locally can be as much as 25 meters. These
descriptions are generally similar to the findings in our field explorations.
4.3 SOILS
The soils encountered during field exploration include loose to very dense silty sand with
gravel. The soil generally becomes denser with depth.
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Nordic Ridge Plat, Renton, Washington RGI Project No. 2015-097
More detailed descriptions of the subsurface conditions encountered are presented in
the test pits included in Appendix A. Sieve analysis was performed on three selected soil
samples. Grain size distribution curves are included in Appendix A.
4.4 GROUNDWATER
No groundwater seepage was encountered during our subsurface exploration. However,
iron oxide staining was observed at 3 to 4 feet indicating a perched seasonal groundwater
table over the top of dense glacial till layer.
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.
4.5 SEISMIC CONSIDERATIONS
Based on the 2012 International Building Code (IBC), RGI recommends the follow seismic
parameters for design.
Table 1 2012 IBC
Parameter Value
Site Soil Class1 C2
Site Latitude 47.44399o N
Site Longitude 122.18701o W
Short Period Spectral Response Acceleration, SS (g) 1.386
1-Second Period Spectral Response Acceleration, S1 (g) 0.517
Adjusted Short Period Spectral Response Acceleration, SMS (g) 1.386
Adjusted 1-Second Period Spectral Response Acceleration, SM1 (g) 0.672
1. Note: In general accordance with Chapter 20 of ASCE 7. The Site Class is based on the average characteristics of the upper 100 feet
of the subsurface profile.
2. Note: The 2012 IBC and ASCE 7 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 8 feet, and this seismic site class definition considers that very dense 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.
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Nordic Ridge Plat, Renton, Washington RGI Project No. 2015-097
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, 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 King County Code, the site does not
contain geologically hazardous areas.
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 and pavements 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 for the project is expected to include mass grading to achieve lot and
roadway grades, excavating the detention pond, installing underground utilities and
preparing roadway 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.
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Nordic Ridge Plat, Renton, Washington RGI Project No. 2015-097
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 (Graded and disturbed slopes
should be tracked in place with the equipment running perpendicular to the slope
contours so that the track marks provide a texture to help resist erosion and
channeling. Some sloughing and raveling of slopes with exposed or disturbed soil
should be expected.)
Decreasing runoff velocities with check dams, straw bales or coir wattles
Confining sediment to the project site
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
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 six to eight inches of topsoil and rootmass. Deeper areas of
stripping may be required in forested or heavily vegetated areas of the site.
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Nordic Ridge Plat, Renton, Washington RGI Project No. 2015-097
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 very dense silty sand with gravel.
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). The slope inclination may be increased to 3/4H:1V in the very dense
till. 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
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 SITE PREPARATION
RGI anticipates that some areas of loose or soft soil will be exposed upon completion of
stripping and grubbing. Proofrolling and subgrade verification should be considered an
essential step in site preparation. After stripping, grubbing, and prior to placement of
structural fill, RGI recommends proofrolling building and pavement subgrades and areas
to receive structural fill. These areas should moisture condition and compacted to a firm
and unyielding condition in order to achieve a minimum compaction level of 95 percent
of the modified proctor maximum dry density as determined by the American Society of
Testing and Materials D1557-09 Standard Test Methods for Laboratory Compaction
Characteristics of Soil Using Modified Effort (ASTM D1557).
Proofrolling and adequate subgrade compaction can only be achieved when the soils are
within approximately ± 2 percent moisture content of the optimum moisture content.
Soils which appear firm after stripping and grubbing may be proofrolled with a heavy
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Nordic Ridge Plat, Renton, Washington RGI Project No. 2015-097
compactor, loaded double-axle dump truck, or other heavy equipment under the
observation of an RGI representative. This observer will assess the subgrade conditions
prior to filling. The need for or advisability of proofrolling due to soil moisture conditions
should be determined at the time of construction. In wet areas it may be necessary to
hand probe the exposed subgrades in lieu of proofrolling with mechanical equipment.
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.
5.2.5 STRUCTURAL FILL
Once stripping, clearing and other preparing operations are complete, cuts and fills can
be made to establish desired lot and roadway grades. Prior to placing fill, RGI
recommends proof-rolling as described above. 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 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. Even during the summer, delays in grading can
occur due to excessively high moisture conditions of the soils or due to precipitation. If
Geotechnical Engineering Report 8 July 8, 2015
Nordic Ridge Plat, Renton, Washington RGI Project No. 2015-097
wet weather occurs, the upper wetted portion of the site soils may need to be scarified
and allowed to dry prior to further earthwork, or may need to be wasted from the site.
The site soils are moisture sensitive and will not be useable for will in wet weather. If
grading operations take place in the summer and fall months, it should be feasible to
moisture condition and compact the native soil. 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.
Table 2 Structural Fill Gradation
U.S. Sieve Size Percent Passing
4 inches 100
No. 4 sieve 75 percent
No. 200 sieve 5 percent *
*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 2. 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
Pavement – Subgrade
and Base Course
On-site granular or approved
imported fill soils: 95 +2 -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.
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Nordic Ridge Plat, Renton, Washington RGI Project No. 2015-097
5.2.6 CUT AND FILL SLOPES
All permanent cut and fill slopes (except interior slopes of detention pond) should be
graded with a finished inclination no greater than 2H:1V. The interior slopes of the
detention pond must be graded with a slope gradient no steeper than 3H:1V. Upon
completion of construction, the slope face should be trackwalked, compacted and
vegetated, or provided with other physical means to guard against erosion.
Final grades at the top of the slopes must promote surface drainage away from the slope
crest. Water must not be allowed to flow in an uncontrolled fashion over the slope face. If
it is necessary to direct surface runoff towards the slope, it should be controlled at the
top of the slope, piped in a closed conduit installed on the slope face, and taken to an
appropriate point of discharge beyond the toe of the slope. All fill placed for slope
construction should meet the structural fill requirements as described in Section 5.2.5.
5.2.7 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
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 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.
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.
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Nordic Ridge Plat, Renton, Washington RGI Project No. 2015-097
Table 4 Foundation Design
Design Parameter Value
Allowable Bearing Capacity - Structural Fill 2,500 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 5.2.5. The recommended base friction and passive
resistance value includes a safety factor of about 1.5.
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 for the future residences or within the detention pond, RGI
recommends cast-in-place concrete walls be used. If grade changes are necessary in lot or
landscape areas, modular block walls can be used. RGI can provide design for modular
block walls once the configuration and height of the walls has been determined.
5.4.1 CAST-IN-PLACE WALLS
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. The perforated pipe shown in the detail may be
replaced with 2 inch diameter weep holes through the wall at 10 foot centers
approximately 6 inches above the wetpond or finished landscape surface for walls in the
detention pond or landscape areas.
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Nordic Ridge Plat, Renton, Washington RGI Project No. 2015-097
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 - Structural Fill 2,500 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 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.
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.
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Nordic Ridge Plat, Renton, Washington RGI Project No. 2015-097
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
The site soils consist of weathered glacial till underlain by very dense unweather glacial
till. Iron oxide staining was observed at the interface of the unweathered till indicative of
a shallow seasonal perched groundwater table. Based on the soil conditions the site is not
suitable for infiltration.
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 King County specifications.
At a minimum, trench backfill should be placed and compacted as structural fill, as
described in Section 5.2.5. 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.
As noted, soils excavated on site will not be suitable for use as backfill material in wet
weather. Imported structural fill meeting the gradation provided in Table 2 may be
necessary for trench backfill. The native soils should be suitable for use as backfill
material in the summer and fall months in dry weather, however moisture condition of
the soils should be expected.
5.8 PAVEMENTS
Pavement subgrades should be prepared as described in Section 5.2 and as discussed
below. Regardless of the relative compaction achieved, the subgrade must be firm and
relatively unyielding before paving. The subgrade should be proofrolled with heavy
construction equipment to verify this condition.
With the pavement subgrade prepared as described above, RGI recommends the
following pavement sections in accordance with the preferred section in the King County
Road Design and Construction Standards - 2007:
For Residential Streets: 2 inches of Class ½ inch Hot Mix Asphalt (HMA) over 4
inches of Class ¾ or 1 inch HMA
The asphalt paving materials used should conform to the Washington State Department
of Transportation (WSDOT) specifications for HMA surfacing.
Geotechnical Engineering Report 13 July 8, 2015
Nordic Ridge Plat, Renton, Washington RGI Project No. 2015-097
Long-term pavement performance will depend on surface drainage. A poorly-drained
pavement section will be subject to premature failure as a result of surface water
infiltrating into the subgrade soils and reducing their supporting capability.
For optimum pavement performance, surface drainage gradients of no less than 2
percent are recommended. Also, some degree of longitudinal and transverse cracking of
the pavement surface should be expected over time. Regular maintenance should be
planned to seal cracks when they occur.
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, Nordic Ridge, LLC, and its 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 Nordic Ridge Plat project in Renton,
Washington, and for the exclusive use of Nordic Ridge, LLC and its 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 test exploration performed on site. Variations in soil conditions can occur, the
nature and extent of which may not become evident until construction. If variations
appear evident, RGI should be requested to reevaluate the recommendations in this GER
prior to proceeding with construction.
Geotechnical Engineering Report 14 July 8, 2015
Nordic Ridge Plat, Renton, Washington RGI Project No. 2015-097
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, 1994, Renton, Washington
7.5-Minute Quadrangle
Approximate Scale: 1"=1000'
0 500 1000 2000 N
Site Vicinity Map
Figure 1
07/2015
Corporate Office
17522 Bothell Way Northeast
Bothell, Washington 98011
Phone: 425.415.0551
Fax: 425.415.0311
Nordic Ridge Plat (Wells Property)
RGI Project Number
2015-097
Date Drawn:
Address: 17709 116th Avenue Southeast, Renton, Washington 98058
SITE
TP-7
TP-6
TP-8
TP-5
TP-4
TP-3
TP-2
TP-1
N
Geotechnical Exploration Plan
Figure 2
Approximate Scale: 1"=100'
0 50 100 200
= Test Pit Location by RGI on 07/01/15
Drawn from ESM Consulting Engineers LLC, Preliminary Plat Plan PP-01.
07/2015
Corporate Office
17522 Bothell Way Northeast
Bothell, Washington 98011
Phone: 425.415.0551
Fax: 425.415.0311
Nordic Ridge Plat (Wells Property)
RGI Project Number
2015-097
Date Drawn:
Address: 17709 116th Avenue Southeast, Renton, Washington 98058
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
07/2015
Corporate Office
17522 Bothell Way Northeast
Bothell, Washington 98011
Phone: 425.415.0551
Fax: 425.415.0311
Nordic Ridge Plat (Wells Property)
RGI Project Number
2015-097
Date Drawn:
Address: 17709 116th Avenue Southeast, Renton, Washington 98058
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
07/2015
Corporate Office
17522 Bothell Way Northeast
Bothell, Washington 98011
Phone: 425.415.0551
Fax: 425.415.0311
Nordic Ridge Plat (Wells Property)
RGI Project Number
2015-097
Date Drawn:
Address: 17709 116th Avenue Southeast, Renton, Washington 98058
Typical Footing Drain Detail
Figure 4
Not to Scale
Geotechnical Engineering Report July 8, 2015
Nordic Ridge Plat, Renton, Washington RGI Project No. 2015-097
APPENDIX A
FIELD EXPLORATION AND LABORATORY TESTING
On July 1, 2015, RGI performed field explorations using a rubber tired backhoe. We
explored subsurface soil conditions at the site by observing the excavation of eight test
pits to a maximum depth of 8 feet below existing grade. The test pits locations are shown
on Figure 2. The test pits 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 pits 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 three of the samples.
Project Name:Nordic Ridge Plat
Project Number:2015-097
Client:Nordic Ridge, LLC
Test Pit No.: TP-1
Date(s) Excavated:7/1/2015
Excavation Method:Backhoe
Excavator Type:Rubber Tire Backhoe
Groundwater Level:Not Encountered
Test Pit Backfill:Cuttings
Logged By ELW
Bucket Size:N/A
Excavating Contractor:Harbor Point
Excavating
Sampling
Method(s)Grab
Location 17709 116th Avenue Southeast, Renton, Washington
Surface Conditions:Grass
Total Depth of Excavation:8 feet bgs
Approximate
Surface Elevation
Compaction Method Bucket
USCS SymbolTPSL
SM
SM
SM
REMARKS AND OTHER TESTS
16% moisture, 24% fines
16% moisture
10% moistureGraphic LogMATERIAL DESCRIPTION
Topsoil
Brown silty SAND with some gravel, loose to medium
dense, moist
Gray silty SAND with some gravel, medium dense to
dense, moist (Weathered Till)
Iron oxide staining
Gray silty SAND with some gravel, dense to very dense,
moist (Glacial Till)
Becomes very dense
Test Pit terminated at 8'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:Nordic Ridge Plat
Project Number:2015-097
Client:Nordic Ridge, LLC
Test Pit No.: TP-2
Date(s) Excavated:7/1/2015
Excavation Method:Backhoe
Excavator Type:Rubber Tire Backhoe
Groundwater Level:Not Encountered
Test Pit Backfill:Cuttings
Logged By ELW
Bucket Size:N/A
Excavating Contractor:Harbor Point
Excavating
Sampling
Method(s)Grab
Location 17709 116th Avenue Southeast, Renton, Washington
Surface Conditions:Grass
Total Depth of Excavation:7 feet bgs
Approximate
Surface Elevation
Compaction Method Bucket
USCS SymbolTPSL
SM
SM
SM
REMARKS AND OTHER TESTS
14% moisture
11% moistureGraphic LogMATERIAL DESCRIPTION
Topsoil
Brown silty SAND with trace gravel, loose to medium
dense, moist
Gray silty SAND with some gravel, medium dense to
dense, moist (Weathered Till)
Iron oxide staining
Gray silty SAND with some gravel, very dense, moist
(Glacial Till)
Test pit terminated at 7'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:Nordic Ridge Plat
Project Number:2015-097
Client:Nordic Ridge, LLC
Test Pit No.: TP-3
Date(s) Excavated:7/1/2015
Excavation Method:Backhoe
Excavator Type:Rubber Tire Backhoe
Groundwater Level:Not Encountered
Test Pit Backfill:Cuttings
Logged By ELW
Bucket Size:N/A
Excavating Contractor:Harbor Point
Excavating
Sampling
Method(s)Grab
Location 17709 116th Avenue Southeast, Renton, Washington
Surface Conditions:Grass
Total Depth of Excavation:7 feet bgs
Approximate
Surface Elevation
Compaction Method Bucket
USCS SymbolTPSL
SM
SM
SM
REMARKS AND OTHER TESTS
11% moisture
14% moisture
10% moistureGraphic LogMATERIAL DESCRIPTION
Topsoil
Brown silty SAND with trace gravel, loose to medium
dense, moist
Gray silty SAND with some gravel, medium dense to
dense, moist (Weathered Till)
Iron oxide staining
Gray silty SAND with some gravel, very dense, moist
(Glacial Till)
Test Pit terminated at 7'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:Nordic Ridge Plat
Project Number:2015-097
Client:Nordic Ridge, LLC
Test Pit No.: TP-4
Date(s) Excavated:7/1/2015
Excavation Method:Backhoe
Excavator Type:Rubber Tire Backhoe
Groundwater Level:Not Encountered
Test Pit Backfill:Cuttings
Logged By ELW
Bucket Size:N/A
Excavating Contractor:Harbor Point
Excavating
Sampling
Method(s)Grab
Location 17709 116th Avenue Southeast, Renton, Washington
Surface Conditions:Grass
Total Depth of Excavation:7.5 feet bgs
Approximate
Surface Elevation
Compaction Method Bucket
USCS SymbolTPSL
SM
SM
SM
REMARKS AND OTHER TESTS
9% moisture
15% moisture
12% moistureGraphic LogMATERIAL DESCRIPTION
Topsoil
Brown silty SAND with trace gravel, loose to medium
dense, moist
Gray silty SAND with some gravel, dense, moist
(Weathered Till)
Iron oxide staining
Gray silty SAND with some gravel, very dense, moist
(Glacial Till)
Test Pit terminated at 7.5'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:Nordic Ridge Plat
Project Number:2015-097
Client:Nordic Ridge, LLC
Test Pit No.: TP-5
Date(s) Excavated:7/1/2015
Excavation Method:Backhoe
Excavator Type:Rubber Tire Backhoe
Groundwater Level:Not Encountered
Test Pit Backfill:Cuttings
Logged By ELW
Bucket Size:N/A
Excavating Contractor:Harbor Point
Excavating
Sampling
Method(s)Grab
Location 17709 116th Avenue Southeast, Renton, Washington
Surface Conditions:Grass
Total Depth of Excavation:6.5 feet bgs
Approximate
Surface Elevation
Compaction Method Bucket
USCS SymbolTPSL
SM
SM
SM
REMARKS AND OTHER TESTS
9% moisture
11% moisture
12% moisture, 35% finesGraphic LogMATERIAL DESCRIPTION
Topsoil
Brown silty SAND with trace gravel, loose to medium
dense, moist
Gray silty SAND with some gravel, dense, moist
(Weathered Till)
Iron oxide staining
Gray silty SAND with trace gravel, very dense, moist
(Glacial Till)
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:Nordic Ridge Plat
Project Number:2015-097
Client:Nordic Ridge, LLC
Test Pit No.: TP-6
Date(s) Excavated:7/1/2015
Excavation Method:Backhoe
Excavator Type:Rubber Tire Backhoe
Groundwater Level:Not Encountered
Test Pit Backfill:Cuttings
Logged By ELW
Bucket Size:N/A
Excavating Contractor:Harbor Point
Excavating
Sampling
Method(s)Grab
Location 17709 116th Avenue Southeast, Renton, Washington
Surface Conditions:Grass
Total Depth of Excavation:6 feet bgs
Approximate
Surface Elevation
Compaction Method Bucket
USCS SymbolTPSL
SM
SM
SM
REMARKS AND OTHER TESTS
11% moisture
12% moisture
12% moistureGraphic LogMATERIAL DESCRIPTION
Topsoil
Brown silty SAND with trace gravel, loose to medium
dense, moist
Gray silty SAND with some gravel, medium dense to
dense, moist (Weathered Till)
Iron oxide staining
Gray silty SAND with some gravel, very dense, moist
(Glacial Till)
Test Pit terminated at 6'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:Nordic Ridge Plat
Project Number:2015-097
Client:Nordic Ridge, LLC
Test Pit No.: TP-7
Date(s) Excavated:7/1/2015
Excavation Method:Backhoe
Excavator Type:Rubber Tire Backhoe
Groundwater Level:Not Encountered
Test Pit Backfill:Cuttings
Logged By ELW
Bucket Size:N/A
Excavating Contractor:Harbor Point
Excavating
Sampling
Method(s)Grab
Location 17709 116th Avenue Southeast, Renton, Washington
Surface Conditions:Grass
Total Depth of Excavation:8 feet bgs
Approximate
Surface Elevation
Compaction Method Bucket
USCS SymbolTPSL
SM
SM
SM
REMARKS AND OTHER TESTS
10% moisture
10% moisture, 20% fines
12% moistureGraphic LogMATERIAL DESCRIPTION
Topsoil
Brown silty SAND with trace gravel, loose to medium
dense, moist
Gray silty SAND with some gravel, medium dense to
dense, moist (Weathered Till)
Iron oxide staining
Gray silty SAND with some gravel, very dense, moist
(Glacial Till)
Test Pit terminated at 8'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:Nordic Ridge Plat
Project Number:2015-097
Client:Nordic Ridge, LLC
Test Pit No.: TP-8
Date(s) Excavated:7/1/2015
Excavation Method:Backhoe
Excavator Type:Rubber Tire Backhoe
Groundwater Level:Not Encountered
Test Pit Backfill:Cuttings
Logged By ELW
Bucket Size:N/A
Excavating Contractor:Harbor Point
Excavating
Sampling
Method(s)Grab
Location 17709 116th Avenue Southeast, Renton, Washington
Surface Conditions:Grass
Total Depth of Excavation:6.5 feet bgs
Approximate
Surface Elevation
Compaction Method Bucket
USCS SymbolTPSL
SM
SM
SM
REMARKS AND OTHER TESTS
9% moisture
13% moisture
11% moistureGraphic LogMATERIAL DESCRIPTION
Topsoil
Brown silty SAND with trace gravel, loose to medium
dense, moist
Brown silty SAND with some gravel, medium dense to
dense, moist (Weathered Till)
Iron oxide staining
Gray silty SAND with some gravel, very dense, moist
(Glacial Till)
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:Nordic Ridge Plat
Project Number:2015-097
Client:Nordic Ridge, LLC
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
Silty SAND (SM)
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 Nordic Ridge Plat SAMPLE ID/TYPE TP-1
PROJECT NO.2015-097 SAMPLE DEPTH 2'
TECH/TEST DATE ELW 7/1/2015 DATE RECEIVED 7/1/2015
WATER CONTENT (Delivered Moisture) Total Weight Of Sample Used For Sieve Corrected For Hygroscopic Moisture
Wt Wet Soil & Tare (gm) (w1)391.8 Weight Of Sample (gm)339.2
Wt Dry Soil & Tare (gm)(w2)339.2 Tare Weight (gm) 15.6
Weight of Tare (gm)(w3)15.6 (W6) Total Dry Weight (gm)323.6
Weight of Water (gm)(w4=w1-w2)52.6 SIEVE ANALYSIS
Weight of Dry Soil (gm) (w5=w2-w3)323.6 Cumulative
Moisture Content (%) (w4/w5)*100 16 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 19.1 2.5" coarse gravel
% C SAND 9.4 2.0" coarse gravel
% M SAND 19.1 1.5"15.6 0.00 0.00 100.00 coarse gravel
% F SAND 28.6 1.0" coarse gravel
% FINES 23.8 0.75"15.6 0.00 0.00 100.00 fine gravel
% TOTAL 100.0 0.50" fine gravel
0.375"51.9 36.30 11.22 88.78 fine gravel
D10 (mm)#4 77.4 61.80 19.10 80.90 coarse sand
D30 (mm)#10 107.9 92.30 28.52 71.48 medium sand
D60 (mm)#20 medium sand
Cu #40 169.7 154.10 47.62 52.38 fine sand
Cc #60 fine sand
#100 240.9 225.30 69.62 30.38 fine sand
#200 262.1 246.50 76.17 23.83 fines
PAN 339.2 323.60 100.00 0.00 silt/clay
DESCRIPTION Silty SAND with some gravel
USCS SM
Prepared For:Reviewed By:KMW
Nordic Ridge, LLC
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 Nordic Ridge Plat SAMPLE ID/TYPE TP-5
PROJECT NO.2015-097 SAMPLE DEPTH 5'
TECH/TEST DATE ELW 7/1/2015 DATE RECEIVED 7/1/2015
WATER CONTENT (Delivered Moisture) Total Weight Of Sample Used For Sieve Corrected For Hygroscopic Moisture
Wt Wet Soil & Tare (gm) (w1)490.4 Weight Of Sample (gm)439.0
Wt Dry Soil & Tare (gm)(w2)439.0 Tare Weight (gm) 15.4
Weight of Tare (gm)(w3)15.4 (W6) Total Dry Weight (gm)423.6
Weight of Water (gm)(w4=w1-w2)51.4 SIEVE ANALYSIS
Weight of Dry Soil (gm) (w5=w2-w3)423.6 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"15.4 0.00 0.00 100.00 cobbles
% C GRAVEL 7.0 3.0"15.4 0.00 0.00 100.00 coarse gravel
% F GRAVEL 4.5 2.5" coarse gravel
% C SAND 3.0 2.0" coarse gravel
% M SAND 10.7 1.5"15.4 0.00 0.00 100.00 coarse gravel
% F SAND 40.3 1.0" coarse gravel
% FINES 34.5 0.75"45.0 29.60 6.99 93.01 fine gravel
% TOTAL 100.0 0.50" fine gravel
0.375"56.9 41.50 9.80 90.20 fine gravel
D10 (mm)#4 64.0 48.60 11.47 88.53 coarse sand
D30 (mm)#10 76.6 61.20 14.45 85.55 medium sand
D60 (mm)#20 medium sand
Cu #40 122.0 106.60 25.17 74.83 fine sand
Cc #60 fine sand
#100 257.1 241.70 57.06 42.94 fine sand
#200 292.9 277.50 65.51 34.49 fines
PAN 439.0 423.60 100.00 0.00 silt/clay
DESCRIPTION Silty SAND with trace gravel
USCS SM
Prepared For:Reviewed By:KMW
Nordic Ridge, LLC
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 Nordic Ridge Plat SAMPLE ID/TYPE TP-7
PROJECT NO.2015-097 SAMPLE DEPTH 4'
TECH/TEST DATE ELW 7/1/2015 DATE RECEIVED 7/1/2015
WATER CONTENT (Delivered Moisture) Total Weight Of Sample Used For Sieve Corrected For Hygroscopic Moisture
Wt Wet Soil & Tare (gm) (w1)329.5 Weight Of Sample (gm)300.7
Wt Dry Soil & Tare (gm)(w2)300.7 Tare Weight (gm) 15.6
Weight of Tare (gm)(w3)15.6 (W6) Total Dry Weight (gm)285.1
Weight of Water (gm)(w4=w1-w2)28.8 SIEVE ANALYSIS
Weight of Dry Soil (gm) (w5=w2-w3)285.1 Cumulative
Moisture Content (%) (w4/w5)*100 10 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 12.1 3.0"15.6 0.00 0.00 100.00 coarse gravel
% F GRAVEL 13.3 2.5" coarse gravel
% C SAND 7.4 2.0" coarse gravel
% M SAND 17.4 1.5"15.6 0.00 0.00 100.00 coarse gravel
% F SAND 29.5 1.0" coarse gravel
% FINES 20.3 0.75"50.0 34.40 12.07 87.93 fine gravel
% TOTAL 100.0 0.50" fine gravel
0.375"68.3 52.70 18.48 81.52 fine gravel
D10 (mm)#4 87.9 72.30 25.36 74.64 coarse sand
D30 (mm)#10 109.0 93.40 32.76 67.24 medium sand
D60 (mm)#20 medium sand
Cu #40 158.7 143.10 50.19 49.81 fine sand
Cc #60 fine sand
#100 223.5 207.90 72.92 27.08 fine sand
#200 242.8 227.20 79.69 20.31 fines
PAN 300.7 285.10 100.00 0.00 silt/clay
DESCRIPTION Silty SAND with some gravel
USCS SM
Prepared For:Reviewed By:KMW
Nordic Ridge, LLC
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