Report OCA =3 )
Carlson Geotechnical Bend Office (541)330-9155 Q►LLSOA_
A Division of Carlson Testing, Inc. Eugene Office (541)345-0289 +
Phone: (503)601-8250 Salem Office (503)589-1252 GEOTECHNICAL
Tigard Office (503)684-3460
Fax: (503)601-8254
RECEIVED
JUN 7 2016
C i T ri
BU1 ;DDh1\'3ivj;*IO] '
Report of
Geotechnical Investigation
Tigard Specialty Food Store
13125 SW Pacific Hwy
Tigard, Oregon
CGT Project Number G1504136
Prepared for
Ms. Karen Brady
Leadership Circle, LLC
1521 Oxbow Dr., Suite 210, PO Box 239
Montrose, Colorado 81402-0239
March 11, 2015
Carlson Geotechnical •PO Box 23814,Tigard,Oregon 97281
Tigard Specialty Food Store
Tigard, Oregon
CGT Project Number G1504136
March 11, 2015
TABLE OF CONTENTS
1.0 INTRODUCTION 4
1.1 Project Information 4
2.0 SCOPE OF SERVICES 4
3.0 SITE INVESTIGATION 5
3.1 Site Geology 5
3.2 Site Surface Conditions 5
3.3 Site Subsurface Conditions 5
4.0 SEISMIC CONSIDERATIONS 7
4.1 Seismic Design 7
4.2 Seismic Hazards 8
5.0 FOUNDATION SETTLEMENT ANALYSES 9
6.0 CONCLUSIONS 10
7.0 RECOMMENDATIONS 11
7.1 Site Preparation 11
7.2 Temporary Excavations 12
7.3 Wet Weather Considerations 13
7.4 Structural Fill 14
7.5 Shallow Spread Foundations 16
7.6 Floor Slabs 17
7.7 Flexible Pavements 18
7.8 Additional Considerations 20
8.0 RECOMMENDED ADDITIONAL SERVICES 20
8.1 Design Review 20
8.2 Observation of Construction 20
9.0 LIMITATIONS 21
TABLES
Table 1 Seismic Ground Motion Values 7
Table 2 Estimated Foundation Settlements from Structural Loads 10
Table 3 Minimum Additional Over Excavation Depths for Soft Clay Soils 10
Table 4 Utility Trench Backfill Compaction Recommendations 15
Table 5 Input Parameters Assigned for Pavement Design 19
Table 6 Recommended Minimum Pavement Sections 19
ATTACHMENTS
Site Location Figure 1
Site Plan Figure 2
Site Photographs Figure 3
Soil Classification Criteria and Terminology Figure 4
Boring Logs Figures 5 through 9
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Tigard Specialty Food Store
Tigard, Oregon
CGT Project Number G1504136
March 11, 2015
• Provide geotechnical engineering recommendations for design and construction of shallow spread
foundations,floor slabs, and flexible pavements.
• Provide recommendations for the Seismic Site Class, mapped maximum considered earthquake
spectral response accelerations, and site seismic coefficients.
• Provide a qualitative evaluation of seismic hazards at the site, including liquefaction potential,
earthquake-induced settlement and landsliding, and surface rupture due to faulting or lateral spread.
• Provide this written report summarizing the results of our geotechnical investigation and
recommendations for the project.
3.0 SITE INVESTIGATION
3.1 Site Geology
Based on available geologic mapping' of the area, the site is underlain by approximately 100 feet of
Pleistocene catastrophic flood deposits originating from glacial outburst floods of Lake Missoula. The
Pleistocene Missoula Lake catastrophic flood deposits were produced by the periodic failure of glacial ice
dams, which impounded Lake Missoula between 21,000 and 12,000 years ago. Floodwaters raged
through eastern Washington and through the Columbia River Gorge. Near Rainier, Oregon, the river
channel was restricted, causing floodwaters to back up the Willamette Valley as far as Eugene.
Floodwaters in the Portland area were as much as 400 feet deep, leaving only the tops of the tallest hills
dry. The flood deposits are typically split into three different facies; the coarse-grained facies, the fine-
grained facies, and the channel facies, which consists of silts, sands, and gravels deposited within the
flood channel. Fine-grained Missoula flood deposits (Mff) are mapped in the vicinity of the site, which
typically consist of silts and fine sands.
3.2 Site Surface Conditions
The site consisted of one, approximately 1.4-acre,tax lot. The site was bordered by SW School Street to
the southwest, SW Pacific Highway to the southeast, an offsite commercial property to the northeast, and
grass playing fields (Tigard Elementary School) to the northwest. The southern portion of the site was
covered with an asphaltic concrete pavement parking lot. The northern portion of the site was grass-
covered. Photographs of the site at the time of our field investigation are attached as Figure 3.
The site was vacant at the time of our investigation. Historical aerial photographs indicate the
northeastern approximate half of the site was previously occupied by a single-story building until about
2005. Since that time,the site has been used for school bus storage.
3.3 Site Subsurface Conditions
3.3.1 Field Investigation-Drilled Borings
CGT observed the advancement of five drilled borings (B-1 through B-5)at the site on February 23, 2015
to depths ranging from about 111/2 to 211/2 feet bgs. The approximate locations of the borings are shown
on the attached Site Plan, Figure 2. The boring locations were determined based on measurements from
existing site features (fences, sidewalks, etc.) and should be considered approximate. The borings were
advanced using mud-rotary and hollow-stem auger drilling techniques using a Deidrich D-50, truck-
' Ma, Madin, Duplantis,and Williams,2012,Lidar-based Surficial Geologic Map and Database of the Greater Portland,Oregon,
Area, Clackamas, Columbia, Marion, Multnomah,Washington, and Yamhill Counties, Oregon,and Clark County,Washington
Oregon Department of Geology and Mineral Industries Open-File Report 0-12-02.
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Tigard Specialty Food Store
Tigard, Oregon
CGT Project Number G1504136
March 11, 2015
Fine-Grained Flood Deposits (CL, ML, SM): Native interbedded silt and sand was encountered below the
fill materials in each exploration and extended to the full depths explored. The interbedded silt and sand
encountered is consistent with the mapped fine-grained Missoula flood deposits discussed in Section 3.1,
and generally consisted of alternating zones of clay, silt, sandy silt, and silty sand. The interbedded silt
and sand ranged in consistency/relative density from soft to very stiff/loose to medium dense. The
predominately fine-grained soils (i.e., clay, silt and sandy silt) typically exhibited non-plastic to medium
plasticity behavior. The predominately coarse-grained soils (i.e., silty sand) typically consisted of fine-to
medium-grained sand.
3.3.4 Groundwater
Groundwater was observed during drilling in boring B-3 at a depth of about 19 feet bgs. Groundwater
stabilized in boring B-1 at a depth of about 14% feet bgs about 4 hours after completion of drilling. We
anticipate that groundwater levels will fluctuate due to seasonal and annual variations in precipitation,
changes in site utilization, or other factors. Additionally, the native fine grained soils are conducive to
formation of perched groundwater.
4.0 SEISMIC CONSIDERATIONS
4.1 Seismic Design
Section 1613.3.2 of the 2014 Oregon Structural Specialty Code (2014 OSSC) requires that the
determination of the seismic site class be based on subsurface data in accordance with Chapter 20 of the
American Society of Civil Engineers Minimum Design Loads for Buildings and Other Structures (ASCE 7).
Based on the results of the explorations and review of geologic mapping, we have assigned the site as
Site Class E for the subsurface conditions encountered. Earthquake ground motion parameters for the
site were obtained based on the United States Geological Survey (USGS) Seismic Design Values for
Buildings - Ground Motion Parameter Web Application2. The site Latitude 45.425308° North and
Longitude 122.781318°West were input as the site location. The following table shows the
recommended seismic design parameters for the site.
Table 1 Seismic Ground Motion Values
Parameter Value
Mapped Acceleration Parameters Spectral Acceleration,0.2 second(Ss) 0.966g
Spectral Acceleration,1.0 second(Si) 0.422g
Coefficients Site Coefficient,0.2 sec.(FA) 0.940
(Site Class D) Site Coefficient,1.0 sec.(Fv) 2.400
Adjusted MCE Spectral MCE Spectral Acceleration,0.2 sec.(SMS) 0.909g
Response Parameters MCE Spectral Acceleration,1.0 sec.(SMi) 1.012g
Design Spectral Acceleration,0.2 seconds(SDs) 0.606g
Design Spectral Response Accelerations
Design Spectral Acceleration,1.0 second(SD,) 0.675g
Seismic Design Category D
2 United States Geological Survey, 2015. Seismic Design Parameters determined using:, "U.S. Seismic Design Maps Web
Application-Version 3.1.0," from the USGS website http.//geohazards.usgs.gov/designmaps/us/application.php.
Carlson Geotechnical Page 7 of 21
Tigard Specialty Food Store
Tigard, Oregon
CGT Project Number G1504136
March 11, 2015
4.2.3 Surface Rupture
4.2.3.1 Faulting
Although the site is situated in a region of the country with known active faults and historic seismic
activity, no known faults exist on or immediately adjacent to the site. Therefore,the risk of surface rupture
at the site due to faulting is considered low.
4.2.3.2 Lateral Spread
Surface rupture due to lateral spread can occur on sites underlain by liquefiable soils that are located on
or immediately adjacent to slopes steeper than about 3 degrees (20H:1 V), and/or adjacent to a free face,
such as a stream bank or the shore of an open body of water. During lateral spread, the materials
overlying the liquefied soils are subject to lateral movement downslope or toward the free face. Given the
lack of a free face in the vicinity of the site, the risk of surface rupture due to lateral spread is considered
low.
5.0 FOUNDATION SETTLEMENT ANALYSES
A primary geotechnical consideration for this site is the potential for excessive total and differential
settlement due to the static loads. The potential for excessive total settlement exists for column footings
founded in the fine-grained flood deposits (CL, ML, SM) encountered at the site. The potential for
excessive differential settlement exists between column footings and relatively lightly loaded continuous
footings.
CGT performed preliminary settlement analyses to estimate post-construction settlements of conventional
shallow spread foundations supporting structural loads for the proposed building. The analyses were
based on subsurface data collected from the drilled borings, laboratory testing performed on collected soil
samples, the maximum column and continuous footing loads detailed in Section 1.1, and the following
assumptions:
• Shallow spread foundations were evaluated using a maximum soil bearing pressure of 1,500, 2,000,
or 2,500 psf.
• Footing subgrade improvement consists of:
o Over-excavation of the native, soft/loose to medium stiff/medium dense fine-grained flood
deposits (CL, ML, SM) below the bottom-of-footing elevation and backfill with heavily compacted
coarse granular fill below column footings.
o For the column footings, several depths of over-excavation and backfill were evaluated to achieve
a total estimated static settlement of 1 inch or less.
• The spread footings were assumed to be 1-feet thick and embedded 2 feet below existing grade
within the native fine-grained flood deposits (CL, ML, SM).
• Estimates were evaluated for the"worst case"soil profile (hybrid of borings B-1 and 6-2).
• Lower estimated total and differential settlements would be indicated for soil profiles at other boring
locations with better blow count(N Value)soils and for lighter loads.
The following table presents representative results of our preliminary settlement analyses for shallow
spread foundations supporting the proposed building.
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Tigard Specialty Food Store
Tigard, Oregon
CGT Project Number G1504136
March 11, 2015
The native, fine-grained flood deposits (CL, ML, SM) are susceptible to disturbance during wet weather.
Trafficability of these soils may be difficult, and significant damage to the subgrade could occur, if
earthwork is undertaken without proper precautions at times when the exposed soils are more than a few
percentage points above optimum moisture content. Geotechnical recommendations for wet weather
construction are presented in Section 7.3 of this report.
The following paragraphs present specific geotechnical recommendations for design and construction of
the proposed development.
7.0 RECOMMENDATIONS
The recommendations presented in this report are based on the information provided to us, results of the
field investigation, laboratory data, and professional judgment. CGT has observed only a small portion of
the pertinent subsurface conditions. The recommendations are based on the assumptions that the
subsurface conditions do not deviate appreciably from those found during the field investigation. CGT
should be consulted for further recommendations if the design and/or location of the proposed
development changes, or variations and/or undesirable geotechnical conditions are encountered during
site development.
7.1 Site Preparation
7.1.1 Site Stripping
Existing undocumented fill, vegetation, and rooted soils should be removed from the building footprint and
pavement areas, and for a 5-foot-margin around such locations. Based on the results of our field
explorations, stripping depths at the site are typically anticipated to extend to approximately ' -foot bgs
across the site. Areas of fill up to 5 feet deep, as was observed in boring B-4, should be over excavated if
encountered within the building footprint. These materials may be deeper or shallower at locations away
from our explorations. Stripping depths will be deeper in areas of tree removal. The geotechnical
engineer or his representative should provide recommendations for actual stripping depths based on
observations during site stripping. Stripped topsoil and rooted soils should be transported off-site for
disposal, or stockpiled for later use in landscaped areas.
7.1.2 Grubbing
Grubbing of shrubs and trees should include the removal of the root mass, and roots greater than 1-inch
in diameter. Grubbed materials should be transported off-site for disposal. Where root masses are
removed, the resulting excavation should be properly backfilled with imported granular structural fill in
conformance with Section 7.4.2 of this report, as needed to achieve design subgrade elevations.
7.1.3 Existing Utilities& Below-Grade Structures
All existing utilities at the site should be identified prior to excavation. Abandoned utility lines beneath the
new building, pavements, and exterior hardscaping should be completely removed or grouted full. Soft,
loose, or otherwise unsuitable soils encountered in utility trench excavations should be removed and
replaced with structural fill as described in Section 7.4 of this report. No below-grade structures were
encountered in our explorations; however, at least one building was previously located at the site. If
encountered during site preparation, buried structures (i.e. footings, foundation walls, slabs-on-grade,
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Tigard Specialty Food Store
Tigard, Oregon
CGT Project Number G1504136
March 11, 2015
utility excavations, we recommend placing trench stabilization material at the base of the excavations.
Trench stabilization material should be in conformance with Section 7.4.4 of this report.
7.2.3 OSHA Soil Type
For use in the planning and construction of temporary excavations up to 8 feet in depth, an OSHA soil
type"C"may be used for the native fine-grained flood deposits(CL, ML, SM).
7.2.4 Excavations Near Foundations
Excavations near footings should not extend within a 1H:1V (horizontal to vertical) plane projected out
and down from the outside, bottom edge of the footings. In the event that excavation needs to extend
below the referenced plane, temporary shoring of the excavation and/or underpinning of the subject
footing may be required. The geotechnical engineer should be consulted to review proposed excavation
plans for this design case to provide specific recommendations.
7.3 Wet Weather Considerations
For planning purposes,the wet season should be considered to extend from late September to late June.
It is our experience that dry weather working conditions should prevail between early July and the middle
of September. Notwithstanding the above, soil conditions should be evaluated in the field by the
geotechnical engineer or his representative at the initial stage of site preparation to determine whether
the recommendations within this section should be incorporated into construction.
7.3.1 General
The near-surface native fine-grained flood deposits (CL, ML, SM) are susceptible to disturbance during
wet weather. Trafficability of these soils may be difficult, and significant damage to subgrade soils could
occur, if earthwork is undertaken without proper precautions at times when the exposed soil is more than
a few percentage points above optimum moisture content. For construction that occurs during wet
weather, site preparation activities may need to be accomplished using track-mounted equipment, loading
removed material onto trucks supported on granular haul roads, or other methods to limit soil disturbance.
A geotechnical representative from CGT should evaluate the subgrade during excavation by probing
rather than proof rolling. Soils that have been disturbed during site preparation activities, or soft or loose
areas identified during probing, should be over-excavated to firm, stable subgrade, and replaced with
imported granular structural fill.
7.3.2 Geotextile Separation Fabric
We recommend a geotextile separation fabric be placed to serve as a barrier between the prepared fine-
grained subgrade and granular fill/base rock in areas of repeated or heavy construction traffic. The
geotextile fabric should meet the requirements presented in the current Oregon Department of
Transportation (ODOT)Standard Specification for Construction, Section 02320.
7.3.3 Granular Working Surfaces (Haul Roads&Staging Areas)
Haul roads subjected to repeated heavy, tire-mounted, construction traffic (e.g. dump trucks, concrete
trucks, etc.) will require a minimum of 18 inches of imported granular material. For light staging areas,
12 inches of imported granular material should be sufficient. Additional granular material, geo-grid
reinforcement, or cement amendment may be recommended based on site conditions and/or loading at
the time of construction. The imported granular material should be in conformance with Section 7.4.2 of
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Tigard Specialty Food Store
Tigard, Oregon
CGT Project Number G1504136
March 11, 2015
Proper moisture conditioning and the use of vibratory equipment will facilitate compaction of these
materials.
Compaction of structural fill with high percentages of particle sizes in excess of 11/2-inches should be
evaluated by periodic proof-roll observation or continuous observation by the CGT geotechnical
representative during fill placement, since it cannot be tested conventionally using a nuclear densometer.
Such materials should be "capped" with a minimum of 12 inches of 11/2-inch-minus (or finer) granular fill
under all structural elements (footings, concrete slabs, etc.).
7.4.3 Floor Slab Base Rock
Floor slab base rock should consist of well-graded granular material (crushed rock) containing no organic
matter or debris, have a maximum particle size of 3 -inch, and have less than 5 percent material passing
the U.S. Standard No. 200 Sieve. Floor slab base rock should be placed in one lift and compacted to not
less than 95 percent of the material's maximum dry density as determined in general accordance with
ASTM D1557(Modified Proctor).
7.4.4 Trench Base Stabilization Material
If groundwater is present at the base of utility excavations, trench base stabilization material should be
placed. Trench base stabilization material should consist of a minimum of 1-foot of well-graded granular
material with a maximum particle size of 4 inches and less than 5 percent material passing the U.S.
Standard No. 4 Sieve. The material should be free of organic matter and other deleterious material,
placed in one lift, and compacted until well-keyed.
7.4.5 Trench Backfill Material
Trench backfill for the utility pipe base and pipe zone should consist of granular material as
recommended by the utility pipe manufacturer. Trench backfill above the pipe zone should consist of
well-graded granular material containing no organic matter or debris, have a maximum particle size of
' -inch, and have less than 8 percent material passing the U.S. Standard No. 200 Sieve. As a guideline,
trench backfill should be placed in maximum 12-inch-thick lifts. The earthwork contractor may elect to
use alternative lift thicknesses based on their experience with specific equipment and fill material
conditions during construction in order to achieve the required compaction. The following table presents
recommended relative compaction percentages for utility trench backfill.
Table 4 Utility Trench Backfill Compaction Recommendations
Backfill Zone Recommended Minimum Relative Compaction
Structural Areas Landscaping Areas
Pipe Base and Within Pipe Zone 90%ASTM D1557 or pipe 88%ASTM D1557 or pipe
manufacturer's recommendation manufacturer's recommendation
Above Pipe Zone 92%ASTM D1557 90%ASTM D1557
Within 3 Feet of Design Subgrade 95%ASTM D1557 90%ASTM D1557
'Includes the proposed buildings,pavements,exterior hardscaping,etc.
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Tigard Specialty Food Store
Tigard, Oregon
CGT Project Number G1504136
March 11, 2015
1. Concrete must be poured neat in excavations or the foundations must be backfilled with imported
• granular structural fill,
2. The adjacent grade must be level,
3. The static ground water level must remain below the base of the footings throughout the year.
4. Adjacent floor slabs, pavements, or the upper 12-inch-depth of adjacent, unpaved areas should not
be considered when calculating passive resistance.
An ultimate coefficient of friction equal to 0.35 may be used when calculating resistance to sliding for
footings founded on the native soils described above. An ultimate coefficient of friction equal to 0.45 may
be used when calculating resistance to sliding for footings founded on a minimum of 6 inches of imported
granular structural fill (crushed rock)that is properly placed and compacted during construction.
7.5.5 Subsurface Drainage
Recognizing the predominantly fine-grained nature of the site soils, placement of perimeter foundation
drains is recommended at the outside base elevations of continuous wall footings. Foundation drains
should consist of a minimum 4-inch-diameter, perforated, HDPE (High Density Polyethylene) drainpipe
wrapped with a non-woven geotextile filter fabric. The drains should be backfilled with a minimum of
2 cubic feet of open graded drain rock per lineal foot of pipe. The drain rock should be encased in a
geotextile filter fabric in order to provide separation from the surrounding fine-grained soils. Foundation
• drains should be positively sloped and should outlet to a suitable discharge point. A representative from
CGT should be contacted to observe the drains prior to backfilling. Roof drains should not be tied into
foundation drains.
7.6 Floor Slabs
7.6.1 Subqrade Preparation
Satisfactory subgrade support for floor slabs constructed on grade, supporting up to 200 psf area loading,
can be obtained from the native, medium stiff/medium dense to better, fine-grained flood deposits (CL,
ML, SM), or on structural fill that is properly placed and compacted on these materials during
construction. Where soft clay (CL) soils are exposed at design subgrade elevations, CGT recommends
the subgrade be over excavated a minimum of 12 inches as detailed in Table 3 of Section 5.0. The over
excavation depth can include the 6-inch thick base rock recommended in Section 7.6.2. The actual
overexcavation depth required, where soft clay is encountered, will also depend on the consistency of the
soils encountered at the bottom of overexcavation depth.
The geotechnical engineer or his representative should observe floor slab subgrade soils to evaluate
surface consistencies. If soft, loose, or otherwise unsuitable soils are encountered, they should be over-
excavated as recommended by the CGT geotechnical representative at the time of construction. The
resulting over-excavation should be brought back to grade with imported granular structural fill as
described in Section 7.4.2.
7.6.2 Crushed Rock Base
Concrete floor slabs should be supported on a minimum 6-inch-thick layer of crushed rock (base rock) in
conformance with Section 7.4.3 of this report. We recommend "choking"the surface of the base rock with
Carlson Geotechnical Page 17 of 21
Tigard Specialty Food Store
Tigard, Oregon
CGT Project Number G1504136
March 11, 2015
If any of the items listed need to be revised, please contact us and we will reassess the pavement design
sections provided in
Table 5 Input Parameters Assigned for Pavement Design
Input Parameter Design Value+ Input Parameter Design Value1
Silt(ML)and Lean Clay(CL)
Pavement Design Life 20 years Resilient Subgrade 5,000 psi
Annual Percent Growth 0 percent Modulus4 Crushed Aggregate Base 22,500 psi
Serviceability 4.2 initial,2.5 terminal Structural Crushed Aggregate Base 0.10
Reliability2 75 percent Coefficient2 Asphalt 0.42
Standard Deviation2 0.49 APAO Level II"Light" 10,000 to 50,000
Vehicle Traffics Parking(<500 stalls) ESAL
APAO Level III"Low Moderate" 50,000 to
Drainage Factor3 1.0
Entrances and Drive Lanes 100,000 ESAL
1 If any of the above parameters are incorrect,please contact us so that we may revise our recommendations,if warranted.
2 Value based on guidelines presented in Section 5.3 of the 2007 ODOT Pavement Design Manual for flexible pavements.
3 Assumes good drainage away from pavement,base,and subgrade is achieved by proper crowning of subgrades.
4 Values based on experience with similar soils prepared as recommended in this report.
5 ESAL=Total 18-Kip equivalent single axle load. Traffic levels taken from Table 3.1 of APAO manual. If an increased traffic load is estimated,
please contact us so that we may refine the traffic loading and revise our recommendations,if warranted.
7.7.3 Recommended Minimum Pavement Sections
The following table presents the minimum flexible pavement sections for the traffic levels indicated in the
preceding table, based on the referenced design procedures.
Table 6 Recommended Minimum Pavement Sections
Minimum Thickness(inches)
Material APAO Level II APAO Leven!!
(Passenger Car Traffic Only) (Entrance/Service Drive Lanes)
Asphalt Pavement(inches) 31/2 4
Crushed Aggregate Base(inches)a 10 12
Subgrade Soils Prepared in accordance with Section 7.1.3.
a Thickness shown assumes dry weather construction. A granular sub-base section and/or a geotextile separation fabric may be required
in wet conditions in order to support construction traffic and protect the subgrade. Refer to Section 7.37.3 for additional discussion.
Carlson Geotechnical Page 19 of 21
Tigard Specialty Food Store
Tigard, Oregon
CGT Project Number G1504136
March 11, 2015
• Placement of Foundation Drains and Other Drains.
• Compaction of Base Rock for Pavements.
• Compaction of Asphaltic Concrete for Pavements.
It is imperative that the owner and/or contractor request earthwork observations and testing at a
frequency sufficient to allow the geotechnical engineer to provide a final letter of compliance for the
earthwork activities.
9.0 LIMITATIONS
We have prepared this report for use by the owner/developer and other members of the design and
construction team for the proposed development. The opinions and recommendations contained within
this report are not intended to be, nor should they be construed as a warranty of subsurface conditions,
but are forwarded to assist in the planning and design process.
We have made observations based on our explorations that indicate the soil conditions at only those
specific locations and only to the depths penetrated. These observations do not necessarily reflect soil
types, strata thickness, or water level variations that may exist between or away from our explorations. If
subsurface conditions vary from those encountered in our site explorations, CGT should be alerted to the
change in conditions so that we may provide additional geotechnical recommendations, if necessary.
Observation by experienced geotechnical personnel should be considered an integral part of the
construction process.
The owner/developer is responsible for ensuring that the project designers and contractors implement our
recommendations. When the design has been finalized, prior to releasing bid packets to contractors, we
recommend that the design drawings and specifications be reviewed by our firm to see that our
recommendations have been interpreted and implemented as intended. If design changes are made, we
request that we be retained to review our conclusions and recommendations and to provide a written
modification or verification. Design review and construction phase testing and observation services are
beyond the scope of our current assignment, but will be provided for an additional fee.
The scope of our services does not include services related to construction safety precautions, and our
recommendations are not intended to direct the contractor's methods, techniques, sequences, or
procedures, except as specifically described in our report for consideration in design.
Geotechnical engineering and the geologic sciences are characterized by a degree of uncertainty.
Professional judgments presented in this report are based on our understanding of the proposed
construction, familiarity with similar projects in the area, and on general experience. Within the limitations
of scope, schedule, and budget, our services have been executed in accordance with the generally
accepted practices in this area at the time this report was prepared; no warranty, expressed or implied, is
made. This report is subject to review and should not be relied upon after a period of three years
Carlson Geotechnical Page 21 of 21
TIGARD SPECIALTY GROCERY STORE- TIGARD, OREGON FIGURE 2
Project Number G1504136 Site Plan
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LEGEND
C.,P- T-J'` B-1® Location of drilled boring. Approximate Scale: 1 Inch= 60 Feet NOTES;
Drawing based on observations made while on site and Conceptual
503.6® Orientation of site photographs shown on Figure 2. 0 60 120 Site Plan prepared by Vega Architecture,LLC,dated 1/13/15.
TIGARD SPECIALTY GROCERY STORE- TIGARD, OREGON FIGURE 4
Project Number G1504136 USCS
Classification of Terms and Content USCS Grain Size
NAME: MINOR Constituents(12-50%);MAJOR Fines <#200(.075 mm)
Constituents(>50%);Slightly(5-12%) Fine #200-#40(.425 mm)
Relative Density or Consistency Sand Medium #40-#10(2 mm)
Color Coarse #10-#4(4.75)
Moisture Content Fine #4-0.75 inch
Plasticity Gravel
Trace Constituents(0-5%) Coarse 0.75 inch-3 inches
- Other:Grain Shape,Approximate Gradation, 3 to 12 inches;
Organics,Cement,Structure,Odor... Cobbles scattered<15%est.
Geologic Name or Formation:Fill,Willamette Silt,Till,Alluvium, numerous>15%est.
etc. Boulders >12 inches
Relative Density or Consistency
Granular Material Fine-Grained(cohesive)Materials
SPT Density SPT Torvane tsf Pocket Pen tsf Consistency Manual Penetration Test
N-Value N-Value Shear Strength Unconfined
<2 <0.13 <0.25 Very Soft Thumb penetrates more than 1 inch
0-4 Very Loose 2-4 0.13-0.25 0.25-0.50 Soft Thumb penetrates about 1 inch
4.10 Loose 4-8 0.25-0.50 0.50-1.00 Medium Stiff Thumb penetrates about 1/4 inch
10-30 Medium Dense 8-15 0.50-1.00 1.00-2.00 Stiff Thumb penetrates less than'/4 inch
30-50 Dense 15-30 1.00-2.00 2.00.4.00 Very Stiff Readily indented by thumbnail
>50 Very Dense >30 >2.00 >4.00 Hard Difficult to indent by thumbnail
Moisture Content Structure
Dry: Absence of moisture,dusty.dry to the touch Stratified:Alternating layers of material or color>6 mm thick
` Damp: Some moisture but leaves no moisture on hand Laminated: Alternating layers<6 mm thick
Moist: Leaves moisture on hand
Wet: Visible free water,likely from below water table Fissured: Breaks along definite fracture planes
Slickensided: Striated,polished,or glossy fracture planes
Plasticity Dry Strength Dilatancy Toughness Blocky: Cohesive soil that can be broken down into small
ML Non to Low Non to Low Slow to Rapid Low,can't roll angular lumps which resist further breakdown
CL Low to Medium Medium to High None to Slow Medium Lenses: Has small pockets of different soils,note thickness
MH Medium to High Low to Medium None to Slow Low to Medium
CH Medium to High High to Very High None High Homogeneous:Same color and appearance throughout
Unified Soil Classification Chart(Visual-Manual Procedure) (Similar to ASTM Designation D-2487)
Major Divisions Group Typical Names
Symbols
Clean GW Well-graded gravels and gravel/sand mixtures,little or no fines
Coarse Gravels:50%or more Gravels GP Poorly-graded gravels and gravel/sand mixtures,little or no fines
Grained retained on
the No.4 sieve Gravels GM Silty gravels,gravel/sand/silt mixtures
Soils: with Fines GC Clayey gravels,gravel/sand/clay mixtures
More than
50%retained Clean SW Well-graded sands and gravelly sands,little or no fines
Sands:More than Sands SP Poody-graded sands and gravellysands,little or no fines
on No.200 50%passing the y�
sieveNo.4 sieve Sands SM Silty sands,sand/silt mixtures
with Fines SC Clayey sands,sand/clay mixtures
ML Inorganic silts,rock flour,clayey silts
Fine-Grained Silt and Clays CL Inorganic clays of low to medium plasticity,gravelly clays,sandy clays,lean clays
Soils: Low Plasticity Fines
50%or more OL Organic silt and organic silty clays of low plasticity
Passes No. MH Inorganic silts,clayey silts
200 Sieve Silt and Clays High Plasticity Fines CH Inorganic clays of high plasticity,fat clays
OH Organic clays of medium to high plasticity
Highly Organic Soils PT Peat,muck,and other highly organic soils
"p.R L`�,` Additional References:
—�� T_ ASTM D2487 Standard Practice for Classification of Soils for Engineering Purposes and
503-601-8250 ASTM D2488 Standard Practice for Description and Identification of Soils(Visual-Manual Procedure)
Carlson Geotechnical FIGURE 6
P-04004,4, 7185 SW Sandburg Street,Suite 110
Tigard,Oregon 97223
3601 8150 Telephone: (503)601-8250 Boring B-2
Fax: (503)601-8254 PAGE 1 OF 1
CLIENT Leadership Circle,LLC PROJECT NAME Tigard Specialty Grocery Store
PROJECT NUMBER G1504136 PROJECT LOCATION 13125 SW Pacific Highway,Tigard,Oregon
DATE STARTED 2/23/15 LOGGED BY HHP ELEVATION DATUM Ft MSL(MetroMap)
- DRILLING CONTRACTOR Subsurface Technologies GROUND ELEVATION 213 ft
EQUIPMENT Diedrich D-50 Truck SEEPAGE --
DRILLING METHOD Hollow Stem Auger GROUNDWATER AT END —
NOTES GROUNDWATER AFTER DRILLING --
w W o tii Z - A WDCP N60 VALUE A
z i- a
a x a 0 U MATERIAL DESCRIPTION 0 a= w >a 0 Q w Z a PL • LL
W" g .i � Z W d5 p,. �> Yom- =,.D 0 MC
-J 0 D 2 Z U U }
W 0 < LU Z d ❑FINES CONTENT(%)❑
(9 0 0 20 40 60 80100
Xxx)( GM SILTY GRAVEL FILL: Dark brown,moist,
- FILLI\angular,gravel up to'/z-inch in diameter. f HSPT 44 6-4-2 19
-
SANDY SILT: Medium stiff,brown,low to no 2-1 (6)
ML plasticity,moist,fine grained sand.
210 SILT: Medium stiff,dark brown,low plasticity,
moist,trace fine grained sand. i
S2P2T 44
(4)2-2-2 29
ML 5 -■-
{ .
A SPT2-3 3-3
- -
(7-4)
205 SANDY SILT: Stiff,brown,moist,low to medium
plasticity,fine to medium grained sand.Sand SPT
content increases with depth. " 2-4 (10)
- 10 ■
200
IIIH
S2-P5T 94 3-5-5
- (10)
SM -■
5 Very stiff below about 15 deet bgs.
li. SPT 2-6 ® 3-9(17)-8
o
o
vi
7-
_
F
z
o 195
CL
06
- - 20
U
Stiff below about 20 feet bgs.
A SPT 2-4-7
- 2-7 33 (11)
I
!-
-
- - •Boring terminated at about 21'/2 feet bgs.
z •No groundwater observed.
o
1g0 •Boring backfilled with granular bentonite upon
2 completion.
0_
X- -w
0
00
U
Carlson Geotechnical FIGURE 8
• 7185 SW Sandburg Street,Suite 110
Tigard,Oregon 97223
c'e rrc"""`°'' Telephone: (503)601-8250 Boring B-4
Fax: (503)601-8254
PAGE 1 OF 1
CLIENT Leadership Circle,LLC PROJECT NAME Tigard Specialty Grocery Store
PROJECT NUMBER G1504136 PROJECT LOCATION 13125 SW Pacific Highway,Tigard,Oregon
DATE STARTED 2/23/15 LOGGED BY HHP ELEVATION DATUM Ft MSL(MetroMap)
DRILLING CONTRACTOR Subsurface Technologies GROUND ELEVATION 212 ft
EQUIPMENT Diedrich 0-50 Truck SEEPAGE —
DRILLING METHOD Hollow Stem Auger GROUNDWATER AT END —
NOTES GROUNDWATER AFTER DRILLING ---
z w
ow-
0
ae w w ♦WDCP N60VALUE•
Ouj Q = >-re >-re s w a
°d O (15
MATERIAL DESCRIPTION z w a j o p Y v z Hc,..
PL • LL
Ur O �Z 0 U }v
w 0 < z a o ❑FINES CONTENT(%)❑
O 0 0 20 40 60 80 100
•p• SILTY GRAVEL FILL: Dark brown to gray,moist, -V SPT 8 9-5
:.: angular,gravel up to'/cinch in diameter. _ /J�` 4-1 28 (14) • •
••
210 �4 2
•
♦•
Q • - -V SPT 11 4-2-3 •
208 ��:• 4
4-2 (5) 15
SANDY SILT: Medium stiff,brown,moist,low V /
206 plasticity,fine grained sand. V SPT 3-3-4
ML 6 4-3 78 (7)
204 SILTY SAND: Medium dense,brown,moist,fine 8 / SPT 2-4-6
SM grained. - 4-4 78 (10) • ❑
49
SANDY SILT: Stiff,brown,low plasticity,moist,
202 fine grained sand. 10
ML
SPT 22 1-3-5
- - - - 4-5 (8)
200 •Boring terminated at about 11'/2 feet bgs.
•No groundwater observed.
•Boring backfilled with granular bentonite upon
- - completion.
198
N_- -
a
A 196
F
0
Q
N
- —
F-
Z
5 194
Co
0
192
a.
U
0
3 190
z
0
-
X 188
w
I-
U'
0