Report (23) URS FELE COPY
July 10, 2003
Tigard-Tualatin School District 23J
6960 SW Sandburg Street
Tigard, Oregon 97223
Attn: Mr. Stephen Poage
Director of Capital Projects
Re: Geotechnical Investigation
Alberta Rider Elementary School
Tigard-Tualatin School District 23J
Tigard, Oregon
URS Job No: 25695391.10001
Dear Mr. Poage:
We are pleased to submit herewith our report entitled "Geotechnical Investigation, Alberta Rider
Elementary School, Tigard-Tualatin School District 23J, Tigard, Oregon." This report formally
documents our conclusions and recommendations regarding the proposed project.
It has been our pleasure to assist you with this project. Should you have any questions regarding
the contents of this report, please call us at your convenience.
Yours very truly,
URS PROP42
447
5984
OREGON q►
c6---er j. _
Bryan J. Duevel, P.E.
EXPIRES: %.7x'31 Jo,, , Brian M. Wi man, Ph.DP.E.
Project Engineer Manager, Geotechnical Engineering
URS Corporation
111 SW Columbia, Suite 900
Portland. OR 97201-5814
Tel 503.222.7200
Fax 503.222.4292
TABLE OF CONTENTS
A Section 1 Introduction 1-1
1.1 General A 1-1
1.2 Proposed Construction 1-1
1.3 Scope of Work 1-1
Section 2 Field and Laboratory Investigations 2-1
2.1 Field Exploration 2-1
2.1.1 Test Pits 2-1
2.1.2 Subsurface Borings 2-1
2.1.3 Dynamic Cone Penetrometer 2-2
2.1.4 Field Resistivity 2-2
2.2 Laboratory Testing 2-2
Section 3 Site Description 3-1
3.1 Surface Conditions 3-1
3.2 Regional Geology 3-1
3.3 Subsuface Conditions 3-1
3.4 Slope Stability Accessment 3-2
3.5 Site Hydrogeology 3-2
Section 4 Design Recommendations 41
4.1 General 4-1
4.2 Shallow Foundations 4-1
4.2.1 Earth Pressures and Friction Factor 4-1
4.2.2 Slabs on Grade 4-2
4.3 Retaining Walls 4-2
4.3.1 Retaining Wall Design Parameters 4-2
4.3.2 Equivalent Fluid Densities 4-3
4.3.3 Additional Lateral Pressures 4-3
4.3.4 Retaining Wall Backfill 4-3
4.4 Site Preparation 4-4
4.4.1 General 4-4
4.4.2 Dry Weather Earthwork 4-4
4.4.3 Wet Weather Earthwork 4-4
4.4.4 Rock Rippability 4-4
4.4.5 Structural Fill 4-5
4.5 Slopes 4-5
4.6 Temporary Shroing 4-6
4.7 Seismic Design 4-6
4.8 Corrosion 4-6
4.9 Pavement Recommendations 4-7
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TABLE OF CONTENTS
• 4.10 Athletic Field Recommendations 4-8
Section 5 Sensitive Site Status 5-1
Section 6 Construction Monitoring 6-1
Section 7 Closure
7-1
Section 8 References 8-1
List of Tables
Table 1 Measured Resistivity 4-6
Table 2 Laboratory Corrosion Tests .... 4-6
Table 3 Assumed Traffic Loading 4-7
Table 4 Recommended Pavement Section 4-7
List of Figures
Figure 1 Vicinity Map
Figure 2 Site Map
Figure 3 Standard Slab and Wall Drainage Detail
List of Appendices
Appendix A Subsurface Exploration Logs
Appendix B Dynamic Cone Penetrometer Test Logs
Appendix C Laboratory Testing
Appendix D Wetlands Review
ik
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SECTIONONE Introduction
1.1 GENERAL
This report presents the results of our geotechnical investigation performed for the proposed
Alberta Rider Elementary School in Tigard, Oregon. This work was completed in accordance
with our proposal to Tigard-Tualatin School District 23J dated May 16, 2003. The project site is
located approximately as shown on the Vicinity Map, Figure 1. The Site Map presented on
Figure 2 shows a preliminary plan layout of the site.
The purpose of this investigation was to explore the surface and subsurface conditions at the site,
analyze the conditions encountered, and prepare design and construction recommendations for
support of the proposed school. These recommendations along with supporting data are
documented in this report.
1.2 PROPOSED CONSTRUCTION
This project involves the construction of a new school with an approximately 40,000 square feet
footprint, a new entrance drive, parking lots, and athletic fields. At the time of this report, two
separate manifestations of the planned development were available. This report is applicable to
either development scenario. For the purposes of this report, we have assumed that column loads
will not exceed approximately 80 kips and continuous wall loads will not exceed 3 kips per lineal
foot. Specific loads and settlement criteria were not available at the time of this report.
1.3 SCOPE OF WORK
The scope of this investigation included completion of the following:
1. Review of previous reports for geotechnical and geological information relevant to the
site. This has been augmented with information obtained from site visits.
2. Examine historical aerial photographs to evaluate historical site development and slope
instabilities.
3. Conduct a subsurface investigation consisting of drilling and sampling at 3 boring
locations and 15 test pit locations to characterize the subsurface soils and bedrock.
4. Perform a laboratory testing program to characterize the physical and engineering
properties of the subsurface soils, including moisture content, plasticity, and gradation.
5. Conduct a geologic site reconnaissance to identify and characterize any unstable
conditions that could adversely impact the site and proposed development.
6. Complete a wetlands review for the site consisting of a site reconnaissance to evaluate the
site for potential wetlands.
7. Recommendations for foundation support of the proposed school. These include
foundation bearing capacities, footing sizes and depths, estimated settlements, earth
pressures and the allowable sliding friction coefficient.
8. Recommendations for slabs-on-grade including subgrade preparation, base course
gradation, compaction and subgrade modulus.
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SECTIONONE Introduction
9. Recommendations for retaining wall and below grade retaining wall design, including
earth pressures for restrained and unrestrained retaining walls. Additionally, drainage and
backfill recommendations are included.
10. General recommendations regarding construction and earthwork.
11. Determination of the corrosion potential at the proposed site with field and laboratory
tests. These tests included field resistivity, pH,chloride and sulfate contents.
12. Perform dynamic cone penetration tests at the site to assess the in situ subgrade
characteristics for pavement design.
13. Recommendations for pavement sections based on the anticipated traffic, pavement life,
and soil conditions encountered. Both "light" and"heavy" duty sections are developed.
14. Recommendations for the design of new play fields including estimated percolation rates,
settlements, drainage and construction considerations.
15. Preparation of 5 copies of this report describing our investigations and recommendations
regarding geotechnical suitability of the site.
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SECTIONTWO Field and Laboratory Investigation
2.1 FIELD EXPLORATION
The field exploration program was conducted on June 4, 5, 13, and 14, and July 1, 2003. The
program consisted of a reconnaissance of the site for visual indications of slope instability and a
subsurface exploration program. The subsurface investigation included the completion of 15 test
pits, 3 soil borings, 11 dynamic cone penetrometer tests, and 4 field resistivity tests.
2.1.1 Test Pits
The 15 tests pits were completed across the site, with a focus on the approximate location of the
proposed school building, as shown on the Site Map, Figure 2. The test pits were excavated by
Brownsfield Environmental and Construction, LLC., of Sandy, Oregon using a Case 9030B
excavator. Test pits were completed to depths of between 12 and 19.5 feet below ground surface
(bgs). The test pits were terminated in bedrock. Representative soil samples were collected from
the test pits prior to being backfilled with the excavated soils. The test pit logs are presented in
Appendix A.
2.1.2 Subsurface Borings
Three soil borings were completed in the vicinity of the proposed school footprint, as shown on
the Site Map, Figure 2. Drilling was performed by Geotech Exploratons,
ctf giin,
Oregon using a truck-mounted CME-75 drill rig. Soil borings were terminated at depths ranging
from 29 to 31 feet bgs and were all terminated in bedrock. Borings were advanced using hollow
stem auger methods to competent bedrock and NX wireline coring methods to the completion of
the boring. Upon completion of the borings, boreholes were backfilled with bentonite chips in
compliance with the state of Oregon Water Resources Department requirements. The soil boring
logs are presented in Appendix A.
Soil samples were obtained during drilling by driving a 2.5 inch inside diameter / 3.25 inch
outside diameter ring sampler (Dames & Moore Type-U) with a 300 pound hammer falling 30
inches. A 140 pound hammer was used to drive the sampler for B-03-2003. Recorded blows
required to advance each 6 inches of penetration are shown on the boring logs. Sampling
resistances for the Type-U Sampler were converted to equivalent Standard Penetration
Resistances (N) using relationships from Winterkorn and Fang (1977) for engineering
calculations. The N value is used to determine the in situ relative density of granular soils and
the consistency of cohesive soils based on established correlations. Field reported blow counts
are recorded on the boring logs. Retrieved ring samples were wrapped in watertight bags, placed
in plastic containers, sealed, and temporarily stored in padded boxes for transportation to our
laboratory. The soil boring logs are presented in Appendix A.
The stratigraphic contacts indicated within each log represent the approximate boundaries
between soil types; actual transitions may be more gradual and indistinct. The soil and
groundwater conditions depicted are only for the specific dates and locations reported, and
therefore, are not necessarily representative of other times and locations.
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SECTIONTWO Field and Laboratory Investigation
2.1.3 Dynamic Cone Penetrometer
Twelve Dynamic Cone Penetration (DCP) tests were performed in areas of the site that may be
paved. The DCP is a widely used device to determine the in situ strength properties of base
materials and subgrade soils. The four main components of the DCP include the cone, rod, anvil
and hammer. The cone is attached to one end of the DCP rod while the anvil and hammer are
attached to the other end. Energy is applied to the cone tip through the rod by dropping the
17.64-pound hammer a distance of exactly 22.6 inches against the anvil. The diameter of the
cone is 0.1575 inches larger than the rod to ensure that only tip resistance is measured. The
number of blows required to advance the cone into the subsurface materials is recorded. The
DCP index is the ratio of the depth of penetration to the number of blows of the hammer. This
can then be correlated to a variety of material properties, including California Bearing Ratio
(CBR) and Resilient Modulus. Logs of the DCP test results are included in Appendix B.
2.1.4 Field Resistivity
The field resistivity of the soils at the site was measured with a Stratascout Model 40C resitivity
meter. Resistance was measured using the 4-point (Wenner) configuration at equal spacings of
5, 10, and 20 feet between each electrode. Four resistivity tests were performed at the locations
shown on the site map, Figure 2.
2.2 LABORATORY TESTING
The soil samples collected as part of the surface and subsurface investigations were tested to
refine the field classifications and to evaluate physical properties of the soils. All tests were
conducted in general accordance with applicable ASTM standards. The laboratory testing
program consisted of the following:
• Visual Soil Classification in general accordance with ASTM Test Method D2487.
• Grain size analysis — Mechanical Testing in general accordance with ASTM Test Method
D422 and D1140.
• Moisture Content in general accordance with ASTM Test Method D2937.
• Liquid and Plastic Limits (Atterberg Limits) in general accordance with ASTM Test Method
D4318.
• pH in general accordance with EPA 150.1.
• Chloride and sulfates in general accordance with EPA 300.0.
The results of the physical laboratory tests conducted are summarized on the soil boring logs in
Appendix A. Plots of the Atterberg Limit tests are contained in Appendix C.
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SECTIONTHREE Site Description
•
3.1 SURFACE CONDITIONS
The site is located near the crest of Bull Mountain as shown on the Vicinity Map, Figure 1. The
topography across most of the site is relatively gentle, with elevations ranging from a high of
approximately 574 feet above Mean Sea Level (MSL) along the northwestern boundary to the
site to 515 feet above MSL in the far southeast corner of the site. The maximum slopes present
onsite approach 25% at the northwest edge of the site. Elsewhere, maximum slopes are
approximately 15%, located in the northwest and southeast portions of the site.
3.2 REGIONAL GEOLOGY
Regionally, the site is located in the northern Willamette Valley physiographic province, an
elongate, roughly north-south trending alluvial valley that lies between the Coastal Range and
Cascade Mountains to the west and east, respectively(On, et. al., 1992). It is also located within
the Portland fold belt, a seismotectonic province defined by Unruh et al. (1994). The tectonic
underpinnings of this latter province are not well understood and complicated by the fact that this
area lies in a transition zone between the rotating forearc block and the continental interior
(Wells et al, 1998).
Specifically, the site is located in the Tualatin Basin, a northwest trending synclinal subbasin to
the Willamette Valley basin (Unruh et al., 1994). The Tualatin Basin is fault bound along its
eastern margin which is bound by the Portland Hills (Madin, 1990). Internal structure to the basin
includes the faulting that has resulted in the formation of the Bull Mountain and Cooper
Mountain anticlines. The site is located immediately south of the anticline axis as mapped by
Madin.
3.3 SUBSURFACE CONDITIONS
The results of the subsurface investigation show that the site is underlain by approximately 5 to 9
feet of medium stiff, brown, lean clay. This clay is weathered late Quaternary windblown silt.
Underlying the weathered silts is 2 to 6 feet of stiff, reddish brown, lean clay. This clay is basalt
bedrock residuum that grades to extremely to highly weathered basalt at depths ranging from 8 to
16 feet below ground surface. The basalt bedrock is Miocene-aged Columbia River Basalts. The
highly weathered basalt is very weak (indicating it can be pealed with a pocketknife) and highly
fractured. The degree of weathering gradually decreases with depth. The rock grades to
moderately weathered, moderately strong (requiring a hammer blow to break a sample) basalt at
depths between 21 and 26 feet bgs.
The Rock Quality Designation (RQD) is commonly used as an index to describe a rock's degree
of fracturing (Deere and Deere, 1989). The RQD is determined by summing the lengths of core
pieces greater than 4 inches over a run and dividing this sum by the total length of the run. RQD
values measured for the moderately weathered basalt ranged from 0 to 32 percent. The fractures
per foot ranged from 5 to greater than 10.
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SECTIONTHREE Site Description
- 3.4 SLOPE STABILITY ASSESSMENT
_ URS conducted a site reconnaissance and aerial photograph review to assess the site and
surrounding properties for potential recent or ancient landslides. Aerial photographs from 1936,
1940, 1963, 1972, 1983, and 1996 were reviewed to assess the site and adjacent properties for
historical slope instabilities. The 1936 and 1940 photographs indicate that the Rider residence is
present along with buildings to the immediate south and east of the Rider property. The site and
surrounding properties are open fields with some orchards. A steep sided drainage leads to the
south-southeast from near the southeast corner of the site. The eastern portion of this site slopes
towards this drainage. Slopes along this drainage appear generally stable though a potential small
surficial failure is present approximately 1000 feet from the site in this drainage. Indications of
global instability were not observed in the 1936 or 1940 aerial photographs.
The drainage to the southeast of the site had become overgrown in the 1963 aerial photograph.
There is a small slope failure immediately north of Beef Bend Road and south of the site by
approximately 2000 feet. There is still one building present to the east and south of the Rider
property. By 1972 the building to the south of the Rider property had been demolished.
Indications of global stability issues were not observed in the 1963 or 1972 aerial photographs.
The site is similar to as it appears today in the 1983 and 1996 aerial photographs. The building to
the east of the Rider property is no longer present. The drainage to the southeast of the site is
heavily overgrown and there are residential buildings on the east side of the drainage.
James Schick, a URS Certified Engineering Geologist conducted a site reconnaissance on June
23, 2003. Evidence of slope instability was not observed on the site. A visual reconnaissance
was also conducted in the drainage to the southeast. Indications of past slope failures including
scarps, pistol-butt tree trunks, hummocky terrain or jackstrawed trees were not observed. Based
on the aerial photograph review and site reconnaissance, there does not appear to be a significant
slope stability issue associated with the site.
3.5 SITE HYDROGEOLOGY
Groundwater was not encountered during the subsurface investigation. URS conducted a review
of water well logs publicly available from the Oregon Water Resources Department. Static
groundwater levels reported on well logs are in excess of 150 feet bgs in the vicinity of the site.
Perched groundwater may be present within the fine-grained soils during the winter months.
However, discharge from these perched systems is anticipated to be minimal.
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SECTIONFOUR Design Recommendations
4.1 GENERAL
Foundation loads for the new school building were provided to URS by Ellis Eslick Associates
Architects. We understand that column loads are not anticipated to exceed 80 kips and
continuous wall loads will not exceed 3 kips per lineal foot. Based on the soil conditions present
at the site, URS recommends the use of conventional continuous or isolated shallow foundations
be used to support the proposed structure.
4.2 SHALLOW FOUNDATIONS
In our opinion, the school can be adequately supported with conventional continuous or isolated
shallow footings. For footings that bear on shallow, undisturbed native soils, we recommend a
net allowable bearing pressure of 2,000 pounds per square foot (psf). For footings founded at a
depth of 10 feet or greater, we recommend a net allowable bearing pressure of 3,000 psf.
Bearing pressures may be increased by one-third when considering transient loads such as wind
and seismic forces. We recommend that a unit weight of 115 pounds per cubic foot (pcf) be used
to calculate the overburden pressure due to excavation. Backfill soils will be slightly heavier
than excavated soils but not enough to significantly influence the bearing pressure.
Exterior footings should be founded at least 18 inches beneath the lowest exterior grade to
provide frost protection. Continuous wall footings should have a minimum width of 18 inches
and isolated column footings should have a minimum plan dimension of 24 inches. Given the
anticipated column loads for the structure, square footings should have a minimum width of 6.5
feet.
We recommend that excavations for foundations be accomplished with a straight-edged grading
bucket to minimize disturbance of the bearing surfaces. Following excavation, the bearing
surfaces should be thoroughly cleaned of loosened or disturbed soil, by hand if necessary. Any
soft or unsuitable soils encountered at the base of foundation excavations should be removed and
replaced with compacted structural fill meeting the requirements described below.
For foundations designed and constructed as specified above, we estimate settlements on the
order of less than 0.5-inch. We anticipate that the majority of the settlement will occur during
construction, essentially as the loads are applied. The remainder of the settlement will likely
occur within three weeks following application of the loads.
4.2.1 Earth Pressures and Friction Factor
Passive earth pressures acting against the toe of the shallow foundations and friction on the base
of the foundations may be considered to provide resistance to lateral forces tending to cause
translational sliding. These structural members should be considered for counteracting lateral
forces only if the member is placed in directcontact with tested and approved soils. If the
foundation is constructed by using forms, lean concrete may be placed between the footing and
the undisturbed wall of the adjacent excavation in order to provide the direct contact required to
consider passive pressure for counteracting lateral movement. The lean concrete should have a
minimum 28-day compressive strength of 1,500 psi. An allowable passive pressure having an
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SECTIONFOUR Design Recommendations
equivalent fluid density of 250 pcf may be used for design. This is based on a factor of safety of
two.
An ultimate friction factor of 0.5 for mass concrete on compacted granular fill can be used for
design for those portions of the foundations with full positive pressure on the base of the
foundation. For foundations placed directly on native clay, an ultimate friction factor of 0.3
should be used. Only long-term dead loads should be considered in calculating the available
friction on the foundation base.
4.2.2 Slabs on Grade
At the time of this report, the final grades had not been determined. As soon as design slab
elevations are known, we should be advised so that we can review and possibly revise the
following recommendations.
The subgrade under all floor slab areas should be prepared in accordance with Section 4.4. We
recommend that floor slabs be underlain by a minimum 6-inch thick granular base course to
provide uniformity of support and to act as a capillary break against moisture migration through
the slab. The granular base course should consist of a well-graded gravel or crushed rock with a
maximum nominal size of 3/a-inch and having less than 5 percent by weight passing the No. 200
sieve. The base course should be compacted to at least 95 percent of its maximum dry density as
determined by the modified proctor test (ASTM Test Method D1557). We recommend a
modulus of subgrade reaction of 225 pounds per cubic inch (pci) for the base course.
Even with a capillary break as outlined above, there is the possibility of some floor moisture or
dampness. If floor moisture is a critical consideration due to storage of materials directly on the
floor slab, or because of the use of glued down impervious floor coverings such as tile or
linoleum, we recommend the use of an under-slab impermeable membrane placed directly below
the slab. To maximize water tightness, the membrane must be installed in accordance with the
manufacturer's recommendations.
4.3 RETAINING WALLS
Following are typical design parameters for wall types that we believe represent the range of
systems that may be constructed at this site. Please contact us if any additional design values or
wall types need to be addressed.
4.3.1 Retaining Wall Design Parameters
Lateral soil pressures on a retaining wall depend on several factors including retained soil type,
wall fixity, drainage provisions and the influence of surface loads imposed behind the wall. We
have provided typical design parameters for wall types that we believe represent the range of
retaining wall systems that are likely to be constructed at this site. Our recommendations are
based on the following assumptions:
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SECTIONFOUR Design Recommendations
• Retaining walls will be designed to restrain both existing soils and constructed fills.
• Retaining walls will be backfilled with free draining crushed rock, in accordance with
Section 4.3.4 of this report.
• Adequate subsurface drainage will be provided.
• Walls will be 12 feet high or less.
4.3.2 Equivalent Fluid Densities
Unrestrained walls have no fixity at the top and are free to rotate about their base through tilting
or translation. Most cantilever retaining walls fall into this category (unless they are attached to
buildings or other structures). A lateral movement of 0.005 times the height of the retaining wall
may be required to achieve this active pressure. For these walls, we recommend that a lateral
equivalent fluid density of 35 pcf be used for design.
Restrained walls are rigid structures where essentially no relative movement occurs between the,
structure and the soil. Most basement walls and other rigid walls that are restrained by buildings,
parking decks, floor slabs or other perpendicular walls fall into the category of restrained walls.
For restrained walls, we recommend that a lateral equivalent fluid density of 55 pcf be used for
design.
4.3.3 Additional Lateral Pressures
Additional lateral support will be provided by passive resistance of soil compacted adjacent to
the sides of the wall foundations. For design purposes, an allowable equivalent fluid density of
250 pcf may be used to estimate the passive resistance. See Section 4.2.1 for additional
information regarding construction requirements to realize this passive earth pressure.
If cohesive soils are used as backfill, hydrostatic pressures or surcharge effects from surface
loads exist, the equivalent fluid density will be significantly higher and URS should be contacted
for additional design information.
4.3.4 Retaining Wall Backfill
Backfill within 3 feet of retaining walls should consist of free draining crushed rock, free of
organics and debris. This material should meet the requirements of the 2002 Oregon Department
of Transportation (ODOT) Standard Specifications for Construction for "Granular Wall
Backfill", Section 00510.12. Backfill beyond 3 feet from the wall should meet requirements
described in Section 4.4.5. We recommend that all fill be compacted to 95% of the maximum
dry density as determined by the Modified Proctor test (ASTM 1557). Additionally, we
recommend that any backfill that is placed within 5 feet of the wall (measured horizontally) be
compacted with lightweight, hand operated compaction equipment. Over-compaction of this fill
can increase wall pressures.
We recommend the placement of a 4-inch diameter slotted PVC pipe wrapped in non-woven
geotextile fabric at the base of the wall backfill to facilitate drainage of this area.
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SECTIONFOUR Design Recommendations
- 4.4 SITE PREPARATION
4.4.1 General
Prior to construction of any new foundations, all areas that will receive fill, base rock, or
structures should be stripped of all surface vegetation, organic topsoil and any deleterious
materials that might be encountered. Any soft or unsuitable soils encountered during stripping or
excavation should be removed and replaced with compacted structural fill meeting the
requirements described in Section 4.4.5.
4.4.2 Dry Weather Earthwork
After areas are stripped or excavated to design elevations, we recommend scarification of the
resulting subgrade in all areas that will receive fill or structures to a depth of 8 inches. The
scarified soil should be brought to 2% above optimum moisture content, and compacted to at
least 95 percent of its maximum dry density as determined by ASTM D698, the Standard Proctor
method.
4.4.3 Wet Weather Earthwork
We anticipate that the native clay found at the site will be susceptible to erosion. Therefore,
during or after wet weather, it may be necessary to import granular materials for structural fill or
to protect open subgrade materials. It may also be necessary to install a granular working pad to
support construction equipment. Delays in site earthwork activities should be anticipated during
periods of heavy rainfall. Additionally, site clearing and stripping activities may expose
subgrade material that may be damaged if subjected to disturbance from construction traffic.
During wet weather, we recommend that site stripping and excavation be performed using an
excavator with a straight-edged bucket that does not traverse the final subgrade.
When a granular working base is used to protect open subgrade material and construction
equipment, the base should consist of a suitable thickness of crushed rock or ballast placed by
end-dumping off an advancing pad of rock fill. Areas that contain native alluvium materials are
moisture sensitive, and it may be necessary to place a geotextile fabric beneath the working
blanket to prevent the intrusion of fines into the rock. Because construction practices can greatly
affect the amount of rock required, we recommend that if conditions require the installation of a
- granular working blanket, the design, installation and maintenance be made the responsibility of
the contractor. After installation, the working blanket should be compacted with a minimum of
four passes with a smooth-drum roller.
4.4.4 Rock Rippability
Rock may be encountered during foundation excavation depending upon the final design and
layout of the new school. Site exploration indicated that the depth to weathered bedrock varies
from 8 to 16 feet below existing grades. The upper 10 feet of this rock (18-26 feet bgs) is highly
weathered and highly fractured. Excavation of the upper portions of this weathered rock (2 to 9
feet) was performed with a Case 9030B excavator and a general purpose bucket. Refusal was
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SECTIONFOUR Design Recommendations
typically encountered at about 15 to 20 feet below ground, close to the maximum reach of the
excavator.
We recommend the use of heavy excavation equipment outfitted with rock buckets to excavate
the weathered rock. We do not anticipate the need for blasting or pneumatic breakers to achieve
foundation grades.
4.4.5 Structural Fill
We recommend that all fills intended to support structures be placed in horizontal lifts not
exceeding about 8 inches in loose thickness and be compacted to at least 95 percent of the
maximum dry density as determined by the Modified Proctor method (ASTM D1557), unless
where specified above.
Imported structural fill should be clean, well graded granular material, free of organics and debris
and meeting the requirements of the 2002 ODOT Standard Specifications for Construction for
"Granular Structural Backfill", Section 00510.13. The procedure to achieve proper density of a
compacted fill depends on the size and type of compacting equipment, the number of passes,
thickness of the layer being compacted, and certain soil properties. When the size of the
excavation restricts the use of heavy equipment, smaller equipment can be used, and the soil
must be placed in lifts thin enough to achieve the required compaction. We recommend that
methods of compaction be left to the discretion of the contractor, with compaction testing
provided by URS.
We do not recommend the use of onsite soils for structural fill. This material may be used for
miscellaneous fill and landscaping applications around the site provided these areas are not
intended to support structures. Onsite soils should be compacted to at least 95% of the
maximum dry density per ASTM D698.
4.5 SLOPES
Depending on the Contractor's proposed excavation and shoring plan, temporary cut slopes may
be required during construction. Cut slope inclinations must be made in accordance with
regulations established by the Oregon Occupational Safety and Health Administration (OR-
OSHA). In accordance with OR-OSHA, the clay soils in the upper 15 feet of the site are
classified as Type B. The maximum allowable slopes for excavation less than 20 feet deep in
_ :
Type B soils is 1H:1V (Horizontal:Vertical). Flatter slopes will be required if water or seepage is
present.
Significant slope work is not anticipated at this site. Allowable finished slopes will depend upon
the type of fill material that is being used, or the location of any cut slopes. For planning
purposes we recommend that any finished cut or fill slopes less than 8 feet high be designed no
steeper than 2H:1 V. Onsite fill used to construct slopes or embankments at the site should be
compacted per Section 4.5.2. All permanent slopes will require erosion protection. Erosion
protection should follow procedures described in the Tigard Community Development Code
Chapter 18.745, "Landscaping and Screening".
URS
\\Por6\projects\25695391 TTSD Alberta RideATTSD Geotech.doc\10-JUL-03
4-5
SECTIONFOUR
4.6 TEMPORARY SHORING Design Recommendations
URS does not anticipate the need for temporary shoring for the recommended overexcavation
activities. Should shoring be necessary for other parts of the project not described in this report,
the Contractor must submit a shoring and excavation plan to the Owner and URS at least 2 weeks
before the start of excavation. The plan should show the design of shoring, bracing, sloping, or
other provisions to be made for worker protection from the hazard of caving ground and for any
trench or excavation over four feet in depth. The shoring and excavation plan must be prepared
and stamped by a civil engineer registered in the State of Oregon.
4.7 SEISMIC DESIGN
The site lies within Seismic Zone 3 as defined by the 1998 version of the OSSC. Based on the
soils encountered during the exploration program, OSSC Soil Type Sc (very dense soil and soft
rock) represents the closest approximation to the site conditions and is recommended for use in
design. The seismic response coefficients that corresponds with Z = 0.3 and Sc are Ca = 0.33 and
C„=0.45 and were obtained from tables 16-Q and 16-R of the UBC, respectively.
4.8 CORROSION
The corrosion potential of site soils was measured by performing field resistivity tests and
laboratory tests for pH, sulfate and chloride content of the samples collected from the site. The
four field resistivity test lines are shown on Figure 2. The results of these tests are shown in
Table 1. The results of the laboratory tests are shown in Table 2.
TABLE 1: MEASURED RESISTIVITY (ohm-cm)
Test Line
Rl
Electrode Spacing
5 10 20
28,400 55,500 155,000
R2 34,500 66,500 143,000
R3 34,300 65,100 132,000
R4 33,400 62,400 140,000
TABLE 2: LABORATORY CORROSION TESTS
Test Pit Depth (ft)
TP-3
pH Sulfate
Chloride
9 5.4
7.18
0.611
TP-6 4 5.4 5.29 0.585
TP-12 7 5.7 5.56 0.629
The results of these tests indicate that the soils are moderately to mildly corrosive to carbon steel.
The risk of sulfate attack on concrete is negligible.
URS
\\Por6\projects\25695391 TTSD Alberta Rider\TTSD Geotech.doc\10-JUL-03
4-6
SECTIONFOUR Design Recomms
VE
4.9 PAVEMENT RECON
We anticipate that vehicle traffic DATIONS will consist of automobiles, buses, and trucks. Estimated traffic
loads were provided to URS by Ellis Eslick Associates Architects. Additional vehicle loads were
estimated for deliveries to the school. Heavy duty pavements are considered to be bus lanes and
the entrance road. Light duty pavement is considered for parking areas.
TABLE 3: ASSUMED TRAFFIC LOADING
Vehicle Type Heavy Duty Light Duty
Automobiles 670 vehicles/day 100 vehicles/week day
Buses 10 vehicles/day 1 vehicle/week day
Heavy Trucks 2 vehicles/week day 1 vehicle/week day
Semi-Trucks 1 vehicle/week day 1 vehicle/week day
Each vehicle will constitute a single pass over the pavement. Following the AASHTO (1986)
procedure, this traffic volume will produce about 310,000 rigid pavement and 285,000 flexible
pavement 18 kip equivalent axle loads (EALs) for the bus lanes and 50,000 flexible pavement
EALs for the parking areas over the design life of 20 years. This is based on an initial
serviceability index of 4.2 and a terminal serviceability index of 2.0.
Using the traffic loads described above and a resilient subgrade modulus of 6,000 psi (based on
dynamic cone penetration tests), the pavement recommendations shown in Table 4 are
recommended. A flexible and rigid heavy duty pavement section were developed. Flexible
pavement may be used for the entry driveway to the school. Rigid pavement should be used in
the proposed bus circle as the tight radius curves may cause shoving and bleeding to the flexible
asphaltic concrete pavement.
Table 4: RECOMMENDED PAVEMENT SECTIONS*
Section 1 —Heavy Duty (Rigid) 4 in. Portland Cement Concrete; over
10 in. Aggregate Base; over
Woven Separation Geotextile; over
8 in. Compacted Subgrade
Section 2—Heavy Duty (Flexible) 4 in. Level 2 HMAC; over .
8 in. Aggregate Base; over
Woven Separation Geotextile; over
8 in. Compacted Subgrade
Section 3 —Light Duty (Flexible) 3 in. Level 2 HMAC; over
6 in. Aggregate Base; over
Woven Separation Geotextile; over
8 in. Compacted Subgrade
*All materials should meet the 2002 ODOT Standard Specifications for Construction.
URS
UPor6Wrojectst25695391 TTSD Alberta Rider\TTSD Geotech.doc110-JUL-03
4-7
SECTIONFOUR Design Recommendations
Areas that are to receive pavement should be stripped and prepared in accordance with the
recommendations in Section 4.4. Stabilizing the subgrade with a woven geotextile separation
fabric (meeting the requirements of AASHTO M288-96 Class 2) will maintain segregation of the
subgrade soil and aggregate base. If the subgrade soils are allowed to migrate upward into the
base course, the result would be decreased pavement support. The aggregate base should
conform to the requirements in the 2002 ODOT Standard Specifications for Construction Section
2630 for 1-1/2-in minus material. Aggregate base should be compacted to 95% of the maximum
dry density as determined by the modified proctor test (ASTM D1557).
We recommend that the hot mix asphaltic concrete and Portland cement concrete conforming to
the 2002 ODOT Standard Specifications for Construction be used for all pavements.
Minimizing subgrade saturation is an important factor in maintaining subgrade strength. Water
allowed to pond on or adjacent to pavements could saturate the subgrade and cause premature
pavement deterioration. To avoid this, the pavement should be sloped to provide rapid surface
drainage, and positive surface drainage should be maintained away from the edge of the paved
areas. Design alternatives that could reduce the risk of subgrade saturation and improve long-
term pavement performance include crowning the pavement subgrade to drain toward the edges,
rather than to the center of the pavement areas; and installing surface drains next to any areas
where surface water could pond. Properly design and constructed subsurface drainage will
reduce the time subgrade soils are saturated and improve subgrade strength and performance.
4.10 ATHLETIC FIELD RECOMMEDATIONS
The native soil below the proposed play fields is entirely composed of clay. This material is
estimated to have an infiltration rate of about 0.05 inches/hour (U.S. Soil Conservation Service,
1986). We recommend the placement of a drainage fill below the play field surface due to the
poor drainage characteristics of the native soils at the site. Drainage fill should consist of free-
draining sand or gravel with less than 5% passing the No. 200 sieve. The subsurface drainage
system should be designed with a conveyance scheme to remove water that collects at the
interface between the drainage fill and the native clay soils.
Construction of the new play fields should be performed in accordance with the
recommendations presented in Section 4.4. URS recommends that construction take place
during the dry season to aid in the prevention of contamination of the drainage fill with fines
from the underlying clay. Drainage fill should be placed in horizontal lifts no greater than 10
inches in thickness and compacted to a minimum of 92% of the maximum dry density as
determined from the Modified Proctor test (ASTM D1557). For play field surfaces designed and
constructed as specified in Section 4.4, we estimate settlements will be negligible.
URS
\\Por6\protects\25695391 TESD Alberta Rider\T SD Geotech.doc\10-JUL-03 4-8
SECTIONFIVE Sensitive Site Status
Tigard Community Development Code Section 18.775 defines "sensitive" sites that may be
unsuitable for development. Included in the definition of sensitive sites are locations where
existing slopes exceed 25%. Existing slopes at the site approach 25% at the northwest edge of
the site, but no new facilities are planned in this area. Slopes in the area of the new structure are
generally less than 10%. Further, the proposed site plan meets the acceptance criteria for sites
built in areas with slopes greater than 25%, outlined in Section Tigard Community Development
Code Chapter 18.775.070.C. These criteria are as follows (description of the site compliance is
provided in italics):
1. The extent and nature of the proposed land form alteration or development will not
create site disturbances to an extent greater than that required for the use;
- The proposed school and appurtenant facilities will disturb only their immediate footprints.
These disturbances will not affect the stability of the site.
2. The proposed land form alteration or development will not result in erosion, stream
sedimentation, ground instability, or other adverse on-site and off-site effects or hazards to
life or property;
- Proper restoration of the site will ensure no erosion and stream sedimentation will occur.
Structures constructed per the recommendations in the report will not adversely affect
ground stability.
3. The structures are appropriately sited and designed to ensure structural stability and
proper drainage of foundation and crawl space areas for development with any of the
following soil conditions: wet/high water table; high shrink-swell capability;
compressible/organic; and shallow depth-to-bedrock; and
- Structures designed and constructed with the parameters and recommendations described
in this report will be stable and provide adequate drainage. Refer to Sections 4.2 through
4.5.
4. Where natural vegetation has been removed due to land form alteration or development, the
areas not covered by structures or impervious surfaces will be replanted to prevent
erosion in accordance with Chapter 18.745, Landscaping and Screening.
- Project specifications must contain a section regarding site restoration insuring the
finished site meets the requirements of Chapter 18.745.
URS
\\Por6\projects\25695391 TTSD Alberta Rider\TTSD Geotech.doc\10-JUL-03 5-1
SECTIONS IX Construction Monitoring
- We mmend URS be retained to provide construction monitoring and testing services
during earthrecowork activities and foundation construction. The purpose of our field monitoring
URS
services is to confirmthat that site conditions are as anticipated, to provide field recommendations as
required based on conditions encountered, and to document the activities of the contractor to
assess compliance with the project recommendations provided by URS.
\\Por6\projects\25695391 TTSD Alberta RldeATTSD Geotech.doc\10-JUL-03 6-1
TS
The analyIONses, conclusions and design recommendations presented in this report are based on site
conditionsSECas they existedEVEN Closure
at the time of our field exploration, and further assume that the
conditions encountered are representative of subsurface conditions within the study area. If
conditions different from those described in this report are encountered or appear to be present
beneath excavations, URS should be advised at once so that additional recommendations may be
provided where necessary.
This report was prepared for the exclusive use of the Tigard-Tualatin School District and its
agents and consultants. It should be made available to prospective contractors for information on
factual data only and not as a warranty of subsurface conditions similar to those interpreted from
the borehole logs or discussions presented in this report.
URS
\\Por6\projects\25695391 TTSD Alberta RideATTSD Geotech.docl10-JUL-03
7-1
SECTIONEIGHT References
American Association of State Highway and Transportation Officials, 1986. AASHTO Guide for
Pavement Structures, AASHTO, Washington D.C.
Deere, D.U., and Deere, D.W., 1989. The Rock Quality Designation
Practice, in Rock
Classifications Systems for Engineering Purposes. Ed. Louis Kirke die,AASTM STP 984,
Philadelphia: American Society for Testing and Materials,pp. 91-101.
Madin, I.P. (1990). Earthquake Hazard Geology Maps of the Portland Metropolitan Area,
Oregon. Oregon Department of Geology and Mineral Industries (DOGAMI), Open-File
Report 0-90-2.
Oregon Department of Transportation, 2002. Oregon Standard Specifications for Construction,
Salem, Oregon.
On, E.L., Orr, W.N. and Baldwin, E.M., 1992, Geology of Oregon, Fourth Edition,
Kendall/Hunt Publishing Company,Dubuque, Iowa.
U.S. Soil Conservation Service, 1986. Technical Release 55: Urban Hydrology for Small
Watersheds, U.S. Department of Agriculture.
Unruh, J.R., Wong, I.G., Bott, J.D.J., Silva, W.J., and Lettis, W.R., 1994. Seismotectonic
Evaluation: Scoggins Dam, Tualatin Project, Northwestern Oregon; William Lettis &
Associates and Woodward-Clyde Federal Services, unpublished final report prepared for the
U.S. Bureau of Reclamation, Denver, CO.
Wells, R.E., Weaver, C.S., and Blakely, R.J., 1998. Forearc Migration in Cascadia and its
Neotectonic Significance: Geology, v. 26, p. 759-762.
Winterkorn, H.F., and Fang, H-Y., 1975. Foundation Engineering Handbook, Van Nostrand
Reinhold Company, N.Y., N.Y.
URS
\\POB\proiects\25695391 TTSD Alberta Rider\TTSD Geotech.doc\10-JUL-03
8-1
litt t J r
w ` 1
• ::"15.::(1
_0-----QC Pt . j , �r { 4,,, A A Typ......
#. -r n./.. ''f - 283` . i � �-
u : Ul`
•
a w•:::4::: 1.
fra '1 ‘.- N.,: [ \‘' /4,i ''', 4.t.1 - . - irs* ' '' Ott'
,g , .... (, 1 f........::..--;-.. ..; ..
:41' ../ . - .5....—..'1: 7*_,. -,,,i,,./1:--- i t:' ..)"'-*. •.:e;_.-.01'...-a,(4+; -.'-,:'.'1,-,4-''.. •7 ' '(
yr 3
\ 1 1.ffffl ( ayJ_fl 0.' •b
/-•
o • s - �/ %� fI Cahr
Y A y
1 ( , • Fr. .8 11 oNi. ain ,'*, ' I > ---."-. •';•• , \ ;'-I. \1 .,.- Iv • ;-:7,A
•i 11 11 11,
a
__--7/
,f�
fz ii
--.---r:
bi
- i -
- .-. ' - -
- ---
, :,.\.,. , .
_ 1 t um_ ,0 «..� ci, �Y s"::::':‘,.
'r. v� $g_,C
L' `/--
�i
-.t _. ". �—`~ � ,•moi 7� _ ',.: _ 'J /
:rf
t,":
:.;:',..:
.7;1/',,,z;
_we_
\ BEEF WI. t s 1; z Y?l
•
ti
i, �1 / eft 4 A
y\ _5- r
i i N.• i�C - :-- •Ls I
\, .i1B 14C
.
SOURCE;S LD MIEST. OREGON USGS TOPOGRAPHIC QUADRANGLE 1986. _,"
II
4r
4
T
t VICINITY MAP
TTSD Alberta Rider Elementary School
1 lintS
July 2003 Geotechnical Investigation
25695391 Tigard, Oregon
FIGURE 1
s
3'
GRANULAR WALL BACKFILL
(SEE NOTE 2) ;0o° \//��
0°o `
0
°oo,
0000 -STRUCTURAL FILL-
°o°o (SEE NOTE 4)
0 0
>o 0 0
0 0 0 0 CONSTRUCTION
)o°o°I CUT SLOPE 1H:1V
J )°0°0
)0000
>° °
J0p0I
VAPOR BARRIER 0 0 0 0
0 0
- )o°o°
' FLOOR SLAB °� )0000 CLAY
` <:. > oo
GRANULAR BACKFILL(SEE NOTE 3) . >°000,
Y//1\\YV//�V. )000 o 0
FOOTING
°
> o'
CLAY OR WEATHERED BASALT .,
4"PERFORATED PIPE
WRAPPED IN FILTER FABRIC
(SEE NOTE 1)
NOTES:
`
1. FILTER FABRIC TO BE NON-WOVEN GEOTEXTILE SUCH AS LINQ 40EX,MIRAFI 140N,OR EQUIVALENT.
2. GRANULAR WALL BACKFILL TO MEET REQUIREMENTS OF THE 2002 ODOT STANDARD SPECIFICATIONS FOR
CONSTRUCTION,SECTION 00510.12. GRANULAR BACKFILL SHOULD BE PLACED WITHIN 3 FEET OF THE WALL.
3. GRANULAR FILL TO CONSIST OF CLEAN,WELL-GRADED,3/4"MINUS DIAMETER CRUSHED ROCK AND SAND
CONTAINING LESS THAN 5 PERCENT PASSING THE NO.200 US STANDARD SIEVE.
4. STRUCTURAL FILL TO MEET THE REQUIREMENTS OF THE 2002 ODOT STANDARD SPECIFICATIONS FOR
CONSTRUCTION,SECTION 00510.13.
3
11
r
STANDARD SLAB &WALL DRAINAGE DETAIL
a
TTSD Alberta Rider Elementary School
URS July 2003 Geotechnical Investigation
25695391 Tigard,Oregon
I FIGURE 3
i
APPENDIX A Subsurface Exploration Logs
•
URS0:\25695391 TESD Alberta Rider\TTSD Geotech.doc\10-JUL-03
Project: TTSD Alberta Rider Elementary School
Project Location: Tigard, Oregon Key to Log of Boring
Project Number: 25695391.10001
SAMPLES
rnm �
C m"� JO 0o aOPV T >4) MATERIAL DESCRIPTION .�
'
REMARKS AND 3E lc U gm F,o OTHER TESTS 2°1 ° m
F- Z rq fr m CC.. (!5 �� U a
0 El 111111 5 6 7 8 ❑9 10 n 12
COLUMN DESCRIPTIONS
nElevation:Elevation in feet referenced to mean sea level 8 Litholoqv Loq:Unified Soil Classification Code(USCS)for
(MSL)or site datum. corresponding lithologic unit.
nDepth: Depth in feet below the ground surface. n Material Description: Description of material encountered;
3 Sample Type: Type of soil sample collected at depth interval may include color,moisture,grain size,and density/consistency.
shown;sampler symbols are explained below. n Water Content: Water content of soil sample measured in
nSample Number: Sample identification number. laboratory,expressed as percentage of dry weight of specimen.
5 Sampling Resistance Number of blows required to advance 11 Percent Passing#200 SievEercentage of sample passing the
driven sampler 12 inches beyond first 6-inch drive interval,or #200 sieve by weight.
distance noted,using a 140-lb hammer with a 30-inch drop; 12 Remarks and Other Tests:Comments and observations
hydraulic down-pressure for tube sampler. regarding drilling or sampling made by driller or field personnel.
F51 Recovery: Percentage of driven or pushed sam le length Other field and laboratory test results,using the following
recovered;"NA"indicates data not recorded. p abbreviations:
7 Graphic Loq: Graphic depiction of subsurface material
encountered;typical symbols are explained below.
TYPICAL MATERIAL GRAPHIC SYMBOLS
Lean Clay Basalt
TYPICAL SAMPLER GRAPHIC SYMBOLS OTHER GRAPHIC SYMBOLS
•
N • Dames&Moore Type U II NX Wireline Coring
o i
m
-
0
a
m Soil classifications are based on the Unified Soil Classification System.Descriptions
U. and stratum lines are interpretive;field descriptions may have been modified to
$ reflect lab test results. 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
o representative of subsurface conditions at other locations or times.
d
URS
Project: TTSD Alberta Rider Elementary School Key to Log of Boring
Project Location: Tigard, Oregon
Project Number: 25695391.10001
KEY TO DESCRIPTIVE TERMS USED ON CORE LOGS
DISCONTINUITY DESCRIPTORS
❑a Dip of discontinuity, measured relative to a plane normal to the core axis.
EllDiscontinuity Type: [] Amount of Infilling:
F - Fault Su - Surface Stain •
J - Joint Sp - Spotty
Sh - Shear Pa - Partially Filled
Fo - Foliation Fi - Filled
V - Vein No - None
B - Bedding
ElAperture(inchesl: ri Surface Shape of Joint:
W - Wide (0.5-2.0) PI - Planar
MW - Moderately Wide (0.1-0.5) Wa - Wavy
N - Narrow (0.05-0.1) St. - Stepped
VN - Very Narrow (<0.05) Ir - Irregular
T - Tight (0)
I I Type of Infilling: n Roughness of Surface:
Cl - Clay Slk - Slickensided [surface has smooth,glassy finish with visual
Ca - Calcite evidence of striations]
Ch - Chlorite S - Smooth [surface appears smooth and feels so to the touch]
Fe - Iron Oxide SR - Slightly Rough [asperities on the discontinuity surfaces are
Gy - Gypsum distinguishable and can be felt]
H - Healed R - Rough [some ridges and side-angle steps are evident;asperities
Mn - Manganese Oxide are clearly visible,and discontinuity surface feels very abrasive]
No - None VR - Very Rough [near-vertical steps and ridges occur on the
Py - Pyrite discontinuity surface]
Qz - Quartz
Sd - Sand
ROCK WEATHERING/ALTERATION
Description Recognition
Residual Soil Original minerals of rock have been entirely decomposed to secondary minerals,and
original rock fabric is not apparent;material can be easily broken by hand
m Completely Weathered/Altered Original minerals of rock have been almost entirely decomposed to secondary minerals,
N although original fabric may be intact;material can be granulated by hand
Highly Weathered/Altered More than half of the rock is decomposed;rock is weakened so that a minimum
m 2-inch-diameter sample can be broken readily by hand across rock fabric
o Moderately Weathered/Altered Rock is discolored and noticeably weakened,but less than half is decomposed;a
minimum 2-inch-diameter sample cannot be broken readily by hand across rock fabric
Slightly Weathered/Altered Rock is slightly discolored,but not noticeably lower in strength than fresh rock
a Fresh/Unweathered Rock shows no discoloration, loss of strength,or other effect of weathering/alteration
a
1
D ROCK STRENGTH
0
G Description Recognition
Li
LL Extremely Weak Rock Can be indented by thumbnail
a Very Weak Rock Can be peeled by pocket knife
i? Weak Rock Can be peeled with difficulty by pocket knife
N Medium Strong Rock Can be indented 5 mm with sharp end of pick
}a. Strong Rock Requires one hammer blow to fracture
w Very Strong Rock Requires many hammer blows to fracture
cc
Extremely Strong Rock Can only be chipped with hammer blows
0
U
o
w
0
n
m
cc` UM
Project: TTSD Alberta Rider Elementary School
Project Location: Tigard, Oregon Log of Boring B-01-2003
Project Number: 25695391.10001 Sheet 1 of 2
- Date(s) 6/13/2003 Logged
Drilled By JDS Checked BJD
Drilling By
Method HSA/Wireline Core Drill
4 1/4"I.D.Auger,NX-Core Toal Depth
Size/Type of Borehole 29.0 FT
- Drill Rig CME 75 Drilling Approximate
Type Contractor Geo-Tech Explorations,Inc. Surface Elevation -568.0 feet MSL
Groundwater Level Not Encountered Sampling
and Date Measured Method(s) D&M Datamer 300 lb
Borehole Bentonite Chips Backfill P Location See Figure 2,Site Map
SAMPLES
oar
3
0O e 0 J0 U� z JU8 vc> L g`� > U o(f) MATERIAL DESCRIPTION EC ..o
>
REMARKSm m cat mp_No t o Nm 0y¢W.92 0:? T220 N2ib .ccc y00 NC!— Z comm 0 J MU s.o_u0
CL —LEAN CLAY[CLJ low plasticity,rapid dilatancy,micaceous,trace- organics,mottled,medium stiff,brown,moist. --
—565 — _
- -
4— / _
■ —
■ 1 7 18
6—� _ —
—560 8— — —
— _
y —
10II _ —
Grades to medium plasticity,no dilatancy,trace basaltic gravel,
-■ 2 13 18 - stiff,reddish brown,moist.
-
o II
0 12— _
m
- _
8 —555 — _
j _
-
" "" Basalt BASALT highly to extremely weathered,veryweak,highly
14— x 9 y — @ 13.5'Driller notes
" • —fractured,Fe,Mn,ClCI filled fractures,<5%vesicles>2mm in dia., less cohesive,more
c x grayish red brown,moist. granular[less
J "% x " -
_ weathered]
- O ■ """"
c) -■
16—■ 3 52 18
mII _
J
Si """x"
N —
x —
00'-550 18— —
oI
u.,
o — —
Q.
-
o 20 y _ 4
a
d
Project: TTSD Alberta Rider Elementary School
Project Location: Tigard, Oregon Log of Boring B-01-203
Project Number: 25695391.10001 Sheet 2 of 2
- SAMPLES
rn-
O a C p J
0)V J O O O
>-- m iu ._ T o a 0� MATERIAL DESCRIPTION a REMARKS
N ; a to vJ > . Oat m..:
Ww Or a O NND 2-2 N -C� 70 mCG:
C U y S
20—F- Z CL!Yt CD J j O O IN W a
4 50 5" 11 "x"x'. Basalt BASALT highly to moderately weathered,moderately strong to U 10_V
ill ,x,x - strong,highly fractured,Fe,Mn,CI filled fractures,5-10%vesicles -
--. %xxxx _<2mm in dia.,trace phenocrysts,brownish gray.
xxxxxx CORE RUN 1 -21-25.25 ft 100%Recovery,RQD 9%,greater than—
x ,"x - 10 fractures per foot. Begin NX-Coring
22— x"" -
`xxxxx —x x x
x x x —
'xxxxxx -
_ x x x
5 51 xxxxxx —
xx"x _
xx
xxx xx
24— xxxx -
_ xxxx -
—
x x x
_ xx
x x"x —
-
,xxxxxx - Grades to moderately to slightly weathered,strong,moderately
26— xxxx fractured,trace vesicles>2mm in dia.trace plagioclase
•:'xxxx —phenocrysts. -
- _ CORE RUN 2-25.25-29 ft:100%Recovery,RQD 32%,5 to>10
fractures per foot.
,6 43 xxxx —
- :xxxx
xx
—540 28— —
,xxx —
- - Boring terminated at a depth of 29.0 feet bgs on 6/13/2003 and
backfilled with bentonite chips upon completion.
30-
32-
-535 —
•
34—
—
8 - —
-N
36— — --
m
N 1 _
a—530 38— — -
( —
J
D _
m —
o —
O -
40—
ki
lL —
-
N
8 —
o
o' 42—
O —
0
a—525 —
— —cc0
a
0
m
¢•
URS
Project: TTSD Alberta Rider Elementary School
Project Location: Tigard, Oregon Log of Boring B-02-2003
Project Number: 25695391.10001 Sheet 1 of 2
- Date(s)
Drilled 6/13/2003 Logged
By JDS Checked BJD
Drilling By
Method HSA/Wireline Core Drill
lt Size/Type 4 1/4"I.D.Auger,NX-Core Total Depth
Drill Rig of Borehole 31.0 FT
Type CME 75 Drilling Geo-Tech Ex Approximate
Contractor ExplorationsInc. Surface Elevation -561.0 feet MSL
Groundwater Level Not Encountered Sampling
and Date Measured Method(s) D&M Hammer 300 lb
Borehole Data
Backfill eho Bentonite Chips Location See Figure 2,Site Map
SAMPLES
rn—
o
�U C o --I O
N O
MATERIAL DESCRIPTION o
E.
U
it 5 m m a) t a�' o _c o.C3 CD w m� rn REMARKS
LTJ..1) 02 a , cumo aUi2 m .0 y« mya
i_ Z wiz m 4= C7 -J o o " a
0 MU lair,
CLLEAN CLAY[CLQ low plasticity,rapid dilatancy,trace organics,
mottled,micaceous,medium stiff,brown,moist. -
-560 - -
2- -
4- -
■
-II
-
-
-555 6-1111 -
6 18
O
- - 30.7 98.7
8- -
10— _
O Grades to medium -
-I plasticity,no dilatancy,some angular basaltic
-550 _II 2 12 18 gravel,stiff,reddish brown,moist.
0 I - - 27 91.2
N —
N _
m 12 - drilling 11.5'-13.5',
-
o softer between 13.5'
0 - _ to 15.0'bgs bgs
-
a.
14- _
_; % % xx Basalt BASALT extremely to highly weathered,extremely weak,highly
3 13 18 x - fractured,CI,Mn,Fe filled fractures,<5%vesicles>2mm in dia., -
m-545 16-, -reddish brown,moist.
LL
O
c:,
%x%x%
N -
i! -
x
oI _ % —
0 18- xxxx -
o j -
Increased drilling
w -
FI - - - resistance 18
¢ _
a
20 _ -
v
Project: TTSD Alberta Rider Elementary School
Project Location: Tigard, Oregon Log of Boring B-02-2003
Project Number: 25695391.10001 Sheet 2 of 2
- SAMPLES
a m
O a)C O --1 0
Of2N 6 J 0 O O
a N
m e ay�, > s o MATERIAL DESCRIPTION m.:.
ww pg� o E Ev, 3 c°�. a oU c 0m REMARKS
>, O [aCDO 0d N U
HC U2?
�L.
I— Z CO�II1 . J? O O a1 to Q
20 �U io_u
XX%XXX Basalt BASALT highly weathered,very weak,highly fractured,Cl,Mn,
4 30 18 X.%.X. - Fe filled fractures,<5%vesicles>2mm in dia.,reddish brown,
—540 —■ X moist.
z X X —
x X x
.x.x
.x _
XX ..
22— ` xX .%%zX —
—
. .xx -
.x zz
zXx —
zzxzzx
x
,xxxXxX
x z x _
24— —
XxX
_ [x.xX
%xzxxxX
]:
- _
Xx% X
5 50-4" 10 XX:XXx:
x X
—535 26-- % X
- ` x:xxx Grades to moderately weathered with highly weathered fracture — Begin NX-Coring
X.X.X. - zones,weak to moderately strong,trace vesicles>2mm in dia., -
% % % —trace phenocrysts,fractures are filled with Cl,Mn,Fe,brownish
`xX.xxX graCORy —
x x - E RUN 1 -26-31 ft:96%Recovery, RQD 0%,>10 fractures
. xxx
` xxx per foot.
28— xX.X.X —Contains several high angle,clay filled fractures -
- 6 58 [xXxxxz
.X.X -
[xX X X -
[XxXXXx% -
XX
30— [ " —
.xX.X X _
cx. Xx _
—530 — X % X
Boring terminated at a depth of 31.0 feet bgs on 6/13/2003 and
backfilled with bentonite chips upon completion. -
32— —
—
•
34, —
—
m —
0
0
-
N
g—525 36— _
m —
m -
ca _
38— _
0
J
a]
o
40—
ili
tL —
N-520 - - -
-
0 -
m
0 42— —
oi _
o
o - -
w
0 _
cc —
0
0
a
c
a
r
IProject: TTSD Alberta Rider Elementary School
Project Location: Tigard, Oregon Log of Boring B-03-2008
Project Number: 25695391.10001 Sheet 1 of 2
Date(s)
Drilled 6/13/2003 Logged Checked
JDSBy g BJD
Drilling HSA/Wireline Core f ypCore
Drill Bit y
Method Size/Type 4 1/4"I.D.Auger,NX- Total Depth
Drill Rigof Borehole 30.0 FT
Type CME 75 Drilling
Contractor Geo-Tech Explorations,Inc. Approximate _562.0 feet MSL
Groundwater Level Surface Elevation
and Date Measured Not Encountered Sampling D&M Hammer
Borehole Method(s) Data 140 lb
Backfill Bentonite Chips Location See Figure 2,Site Map
SAMPLES
rn
o
O 6-.= o J V
0,2 J O o
m 15, a.- 3 --aro,- m s o MATERIAL DESCRIPTION m
wp °7a E E'w 3 c°� a -o U ; . REMARKS
Z roa) o m stn m
H C5 5 U N8 2?
= f CL -–LEAN CLAY(CL]low plasticity,rapid dilatancy,micaceoustrace
organics,mottled,stiff,brown,moist. _,
–560 2– / _ –
_
4- -
_ _
■ Grades to medium plasticity,
■ - stiff,reddish brown,moist -
no dilatancy,trace basaltic gravel,
6-111 18 18
II
–555 – _
8– _ –
_ –
10
■ txxxxxx Basalt BASALT extremely weathered,extremely to very weak[hard),
_■ 2 67 18 highly fractured,remant vesicles,reddish brown,moist.
o ■ _
o — –
Cl _
–550 .xxx
12– x xxx -
fL –
m _
x –
xx
x x
S _ _
xx
a. 14- - -
–
D
—
CO
a
3 106.6, 12 `'xxx Grades to highly weathered, weak to very weak,highly fractured, —
mbrown.
16� Fe,Mn,CI filled fractures,5-15%vesicles>2mm in dia.,grayish red-
-
Cc
O
a-545 – –
U _
xx -
0 18– x
ci xx –
0 x - –
'' ,--I 4 100-4" .33 ' – _
xx
a x ; x brown.
_Grades to highly to moderately weathered, weak to moderately _ Driller notes
20 'xxxxix strong,<5%vesicles>2mm in dia.,grayish b
a significant resistance
d
URS
Project: TTSD Alberta Rider Elementary School
Project Location: Tigard, Oregon Log of Boring B-03-2003
Project Number: 25695391.10001 Sheet 2 of 2
SAMPLES
rn�
C.
O m C o J-8 O
o
>.. a.._ `� r m E. o� MATERIAL DESCRIPTION m
mm mo . nv, v� s o :
w m p?� a E E'w 0—. L 5 aci m a REMARKS
Z f/)�m Q (7 J� o 'a-,',2
20 M U o_o-a
xxxx%% Basalt BASALIS moderately weathered,weak to moderatelystrong,
xx x highly fractured,5%vesicles>2mm in dia.,grayish rown. -
9 Begin NX-Coring
`xXxxxx% CORE RUN 1 -25-30 ft:89%Recovery,RQD 0%,>10 fractures
xxxxx ' per foot. —
xxxxXx
-540 22- X x %
xxxxxx
x x x Moderately to highly weathered zone 22'to 22.5'bgs —
+ 5 60 xxxxx -
x x x
XxX%xX —
z x %
xxxxxx -
x % x -
24— Xxxx% —
—
% X %
Driller notes softer
xxxxxx _ drilling between
xxx
•
xxxx%x Grades to weak,highly fractured,highly weathered lens<6x thick _ 24-25
•xxxxxx - from 25'to30'bgs. -
26— xxxx%x CORE RUN 2-25-30 ft: 50%Recovery,RQD 0%,>10 fractures
% x —per foot.
xX % -
-535 - xxxxx — -
6 30 - —
28- — -
xxx
xxxxx —
30 XXxxx
- - Boring terminated at a depth of 30.0 feet bgs on 6/13/2003 and
backfilled with bentonite chips upon completion. -
—530 32— — -
—
34— — -
—
C" _
0
o _
N
36— — -
m —
m
—525 — — -
—
a 38— — -
o _
J -
m —
- O —
cn -
G 40—
LE —
O
o -
N -
x
2
o—520 42— —
0
ow
2 —
0
a
0
n
m
Q
Project: TTSD Alberta Rider Elementary School
Project Location: Tigard,Oregon Key to Log of Test Pit
Project Number: 25695391.10001
a.
rn
rn
N N N 2 c a ;
to' w E E a MATERIAL DESCRIPTION REMARKS AND
a o OTHER TESTS
W w co co Z 0 0 o N N
2c. Q.
1 2 3❑ 4 5 6
7 8 9
COLUMN DESCRIPTIONS
1 J Elevation:
orsite Elevationdatumin feet referenced to mean sea level 6 Material Description: Description of material encountered;
(MSL) . may include color,moisture,grain size,and
2 Depth: Depth in feet below the ground surface. density/consistency.
7 Moisture Content, /o Moisture content of sample.
3 Sample Type: Type of soil sample collected at depth interval
shown;sampler symbols are explained below. 8 Precent Passing#200 Sieve Precentage of sample passing the
4 Sample Number. Sample identification number. #200 sieve by weight.
Remarks and Other Tests:
and observa
15 I Graphic Log: Graphic depiction of subsurface material 9 regarding excavation or sampling madesby driller or field
encountered;typical symbols are explained below. personnel. Field and laboratory test results(other than water
content), using abbreviations explained below.
TYPICAL MATERIAL GRAPHIC SYMBOLS
i
�� Lean Clay x Basalt
�xx xx�
TYPICAL SAMPLER GRAPHIC SYMBOLS
OTHER GRAPHIC SYMBOLS
8 > Disturbed Sample
N 111
4
a
0 •
0
N
TYPICAL LABORATORY TEST ABBREVIATIONS
a
a
J
Soil classifications are based on the Unified Soil Classification
System.Descriptions and stratum lines are interpretive;field
descriptions may have been modified to reflect lab test results.
LL Descriptions on these logs apply only at the specific test pit locations
o and at the time the test pits were excavated;they are not warranted to
0
be representative of subsurface conditions at other locations or times.
ad
0
>-
0 W
a
a
a
0 m�
Q.
URS
Project: TTSD Alberta Rider Elementary School Log of Test Pit .
Project Location: Tigard, Oregon TP-01-2003
Project Number: 25695391.10001
Date(s) Lo
Excavated 6/412003 By99� JDS Checked BJD
By
Len15.0 feet of Width of Depth of
Excaavation Excavation 3.0 feet Excavation 15.0 feet
Excavation Case 9030 B Trackhoe Excavation Approximate
Equipment Contractor BEC Surface Elevation -
571.0 feet MSL
Water Groundwater Not Encountered
Observations Weather Sunny,80's
Location See Figure 2,Site Map Surface
Condition Grassy Field
co
c
o I.- o
N a) m U o 0_ >
>.- a.- a a.n MATERIAL DESCRIPTION C. REMARKS AND •
m ami °) a°i E EE ;�0 8 o OTHER TESTS
w,.. ow
m m = c
rn rnz 0 MU Zr,
0
/ LEAN CLAY[CL],low plasticity,trace organics,medium stiff,brown,
moist.
—570 -
1
5— _
Increase in moisture content,mottled.
Grades to medium plasticity,trace angular basaltic gravel,stiff,reddish
brown,moist.
j
BASALT,highly weathered, highly fractured,very weak,moist.
Excavator notes difficult
10— —
excavation.
—
—560 - - _
Grades to highly to moderately weathered, weak
0
0
N
O
h-
0
0
g�
0- 15— , .• . .
•
Test Pit terminated at a depth of 15.0'bgs on 6/4/2003 due to hard
excavating conditions.
-J
J
0
m
Ca
rH -
F
1.6
lL - _
O
N
eE
U21
a
f 20— —
I-
rt
0
0
a —550
0
a
m
URS
Project: TTSD Alberta Rider Elementary School
Project Location: Tigard, Oregon Log of Test Pit
Project Number: 25695391.10001 TP-02-2003
Date(s) 6/4/2003 Bogged
Excavated JDS Checked
Length of By BJD
y
Excavation 15.0 feet Width of 3.0 feet Depth of
Excavation Excavation 19.5 feet
Excavation Case 9030 B Treckhoe Excavation
Equipment Contractor BEC Approximate —558.0 feet MSL
Water Surface Elevation
Observations Groundwater Not Encountered Weather Sunny,80's
Location See Figure 2,Site Map Surface
Condition Grassy Field
a) rn
ca..
rn c
O
w CL m 0 U a > REMARKS AND
m a MATERIAL DESCRIPTION OTHER TESTS
IL in
�w as
E E `° Via? m
�o
CO �Z C7 �U w
0
LEAN CLAY[CL],low plasticity,rapid dilatancy,trace organics,
micaceous,medium stiff,brown,moist.
j -
31.7 96.8
5—
—550
Grades to medium plasticity,slow dilatancy, trace angular gravel,stiff,
reddish brown,moist.
j -
10
2 28.4 87.1
•
c1
o -
o
a -
o
15—
a
r BASALT,highly weathered,very weak, highly fractured, 5-10%vesicles
x
>2mm dia.,Fe,CI, Mn filled fractures,moist.
Fa0
LL_ 0 Grades to highly to moderately weathered,weak to moderately strong
0
N
-
X
X n
aI 20— Test pit terminated at a depth of 19.5'bgs on 6/4/2003 due to difficult
excavation last 2.0'.
a.
a.
a
m
URS
.
ProProject:
ectLTTocation:SD Alberta
TigardRiderOregon Elementary School
j , Log of Test Pit
Project Number: 25695391.10001 TP-03-2003
Date(s) 6/4/2003 Logged
Excavated JDS Checked
8y BJD
Excavation of 15 .0 feet Width of 3.0 feet Depth of
Excavation Excavation 19.5 feet
- Excavation Case 9030 B Trackhoe Excavation
Equipment Contractor BEC Approximate -559.5 feet MSL
Water Surface Elevation
Observations Groundwater Not Encountered
Weather Sunny,80's
Location See Figure 2,Site Map Surface
Condition Grassy Field
Ce
O J y
` a a)
w w o E E l MATERIAL DESCRIPTION yin REMARKS AND
y w o OTHER TESTS
in CO)Z 0 _ o
0 �v n�
LEAN CLAY ICLI, low plasticity,rapid dilatancy,trace organics,
micaceous,medium stiff,brown,moist.
5-
Grades to medium plasticity,no dilatancy,trace angular basaltic gravel,
stiff,reddish brown,moist.
j
-550 - 7.18 mg/L,Chlorides =
10- 0.611 mg/L
-
Basaltic clasts increase
8
a
I-
-
m
a. 15-
a x BASALT, highly weathered,very weak, highly fractured, 5-10%vesicles
x >2mm dia.,Fe, CI,Mn filled fractures,reddish brown.
-
J -
VI
Grades to highly to moderately weathered, weak to moderately strong
LL -
0
X X X
x-540
Fa1 _ Test Pit terminated at a depth of 19.5'bgs on 6/4/2003 due to hard
20 -excavating the last 2.5'.
I
0
a.
0
0.
0
!Project: TTSD Alberta Rider Elementary School
Project Location: Tigard, Oregon Log of Test Pit
Project Number: 25695391.10001 TP-04-2003
Excavated 6/4/2003 Logged
By JOS Checked BJH
By
Excavation 15.0 feet Width of 3.0 feet Depth of
Excavation 16.5 feet
Excavation Excavation
Equipment Case 9030 B Trackhoe Excavation BEC Approximate
Contractor Surface Elevation -559.0 feet MSL
Water Groundwater Not Encountered
Observations Weather Sunny,80's
Location See Figure 2,Site Map Surface
Condition Grassy Field
rn
en
O N
ww o°' E E E MATERIAL DESCRIPTION REMARKS AND
Q.
OTHER TESTS
0 !/� V)Z 0 U 0 .N
E U a at
LEAN CLAY[CLI,low plasticity, rapid dilatancy,trace organics,medium
stiff,mottled brown,moist.
j -
1 j
5-
-550
Grades to medium plasticity,slow dilatancy,trace angular gravel,stiff,
mottled reddish brown,moist.
10-
S
increase in basaltic gravel -
a _
o
o
x BASALT,highly weathered,very weak, highly fractured,5-10%vesicles
>2mm dia.,reddish brown,moist.
a 15-
a ` Grades to highly to moderately weathered, weak to moderately strong
a -
-
0
Test Pit terminated at a depth of 16.5'bgs on 6/4/2003 due to hard
k excavating through the last 2.0'.
m
LL _ _
,
0
0
N
m-540 -- -
U
a
a�
�, 20- -
-
I
0
a.
0 0
a
m
Project: TTSD Alberta Rider Elementary School
Project Location: Tigard, Oregon Log of Test Pit
Project Number: 25695391.10001 TP-05-2003
- Date(s)
Excavated 6/412003 Logged
JDS Checked BJD
Lengthy
of B
Excavation 15.0 feet Width of 3.0 feet Depth of
Excavation Excavation 16.5 feet
- Excavation
cavation oximate
Case 9030 B Trackhoe Excavation
Equipment Contractor BEC Surf ce Elevation -556.5 feet MSL
Water Groundwater Not Encountered
Observations Weather Sunny,80's
Location See Figure 2,Site Map Surface
Condition Grassy Field
N 0)
a o) c
O I- J N
-� a-' a) a� s MATERIAL DESCRIPTION a ° REMARKS AND
w�' o.�°' h c o OTHER TESTS
u) to Z C7 0 0 0
0 2c) a*
LEAN CLAY[CL],low plasticity,rapid dilatancy,micaceous,trace
organics,medium stiff,mottled,brown,moist.
29.4 96.4
5
Increase in moisture content
-550
10
2 -
Grades to medium plasticity,slow dilatancy,some angular basaltic gravel, 27.4 84.2
stiff,mottled,reddish brown.
m
g
o
x=x.x= BASALT,highly weathered,very weak,highly fractured,5-10%vesicles
0 >2mm dia.,Fe, Mn,Cl filled fractures, reddish brown.
g - • - -
a_ 15- • -
a x Grades to highly to moderately weathered,weak to moderately strong -
m -
-540
0 Test Pit terminated at depth of 16.5'bgs on 6/4/2003.
-G
Iz -
0
0
N
xk
m -
0
a 20_
N -
Ire0
O
a
0
a
m
Project: TTSD Alberta Rider Elementary School
Project Location: Tigard, Oregon Log of Test Pit
Project Number: 25695391.10001 TP-06-2003
Date(s) 614/2003 Logged
ExcavatedLBy
o JDS Checked BJD
Length of y
Excavation 15.0 feet Width of 3.0 feet Depth of
Excavation Excavation 19.0 feet
Excavation Case 9030 B Trackhoe Excavation
Equipment Contractor BEC Approximate —568.0 feet MSL
Water Surface Elevation
Observations Groundwater Not Encountered Weather Sunny,80's
Location See Figure 2,Site Map Surface
Condition Grassy Field
c &N a,
0) c
O N 0 H
m °' U MATERIAL DESCRIPTION a)-� z REMARKS AND
— ami cp2 a EE o- . . cin
w.- o m ,�a? o OTHER TESTS
to �Z C') oo ago
0 MU o_a
jLEAN CLAY(CL],low plasticity,trace organics,medium stiff,mottled
brown to brownish gray,moist.
pH=5.4,Sulfates=
5— — 5.29 mg/L,Chlorides=
�
; Grades to medium plasticity,some weathered rock fragments,stiff,reddish 0.585 mg/L
Z-(
2 brown,moist.
—560 -
10— !//
X BASALT,completely to highly weathered,extremely to very weak,wet on
X fractures,highly fractured, reddish brown.
CI _
N
a. _
ixxx
0
N
Grades to highly to extremely weathered, very weak
Excavator notes stiff,
a 15— _
a
— not refusal as TP-1
f
J xxx
J
m xxx
0
`X
-
xxx
LL—550 ,, Grades to highly to moderately weathered, weak to very weak
0
m XXX
0 Test Pit terminated at a depth of 19.0'bgs on 6/4/2003 due to practical
ai refusal.
)-, 20— —
—
0
0
a
E
!
m
Project: TTSD Alberta Rider Elementary School
Project Location: Tigard, Oregon Log of Test Pit
Project Number: 25695391.10001 TP-07-2003
- Date(s) 6/4/2003 Logged
Excavated yJDS Checked BJD
By
Length of h of
15.0 feet Width of
Excavation Excavation 3.0 feet Excavation 15.0 feet
Excavation Case 9030 B Trackhoe Excavation
EquipmentContractor BEC Approximate -.563.0 feet MSL
Surface Elevation
Water Groundwater Not Encountered
Observations Weather Sunny,80's
Location See Figure 2,Site Map Surface GrassyField
Condition
m m
c T O 0
fii )
o- o o 63 s MATERIAL DESCRIPTION H
Z,,'' n REMARKS AND
m m a in
OTHER TESTS
csi
U) U)z CD 0 0 0
0 2c.) a.
LEAN CLAY[CLI, low plasticity, rapid dilatancy,micaceous,trace
organics,medium stiff,mottled brown,moist.
-560 -
Grades to brown to brownish yellow
5—
—
a
Grades to medium plasticity,slow dilatancy,some angular basaltic gravel,
stiff,reddish brown. -
10-
C
S -
n
a —55 0 -
S
BASALT, highly weathered,very weak,highly fractured,5-10%vesicles
.2mm dia., Fe,CI, Mn filled fractures.
a. 15 - " ` "
a Test Pit terminated at a depth of 15.0'bgs on 6/4/2003 due to excavator
breakdown.
2
- J
J
D
CO0
N
LL -
_
0
I
C.)
1- 20- -
F -
Ix
a
O
0-
"C c
0
0.
0
UM
Project: TTSD Alberta Rider Elementary School '
Project Location: Tigard, Oregon Log of Test Pit
Project Number: 25695391.10001 TP-08-2003
Date(s) 6/4/2003 Logged
Excavated JOS Checked
By By
BJD
Excavation 15.0 feet WidthExcav
3.0 feet Depth of
Excavation Excavation15.0 feet
Equipment Case 9030 B Trackhoe Excavation BEC Approximate
Contractor Surface Elevation -569.0 feet MSL
Water Groundwater Not Encountered
Observations
Weather Sunny,80's
Location See Figure 2,Site Map Surface
Condition Grassy Field
•
oui
'�
«. L a) a)N U o a >
w w o w E E E MATERIAL DESCRIPTION REMARKS AND
rm in Z o o oo OTHER TESTS
0 Mcg a*
jj LEAN CLAY[CL],low plasticity, rapid dilatancy,trace organics,
miceaous,medium stiff,mottled brown to yellowish brown,moist.
1
5-
2 ` Grades to medium plasticity,slow dilatancy,fine angular basaltic gravel,
medium stiff,moist.
-560
10-
-
BASALT, highly weathered,very weak,5-10%vesicles>2mm dia.,
reddish brown.
o _
0
N
6
9
a
Grades to highly to moderately weathered, weak,grayish brown,highly
0
0
fractured.
ry
a
a.o 15 . xx
0.
Test Pit terminated at a depth of 15.0'on 6/4/2003 due to difficult
excavating conditions.
J
03
m
fn -
I-
1- -
m
LL -
O
O
N
-550 - _
C.)
2
a.
- 20- -
E
0
0.
`o
a
0
Project: TTSD Alberta Rider Elementary School Log of Test Pit ,
Project Location: Tigard, Oregon TP-09-2003
Project Number: 25695391.10001
- Date(s) 6/4/2003 Logged
Excavated By JDS Checked BJD
Length of Width of
Excavation of
15.0 feet Excavation 3.0 feet Excavation 14.5 feet
Excavation Case 9030 B Trackhoe Excavation BEC Approximate
EquipmentContractor Surface Elevation -564.0 feet MSL
Water Groundwater Not Encountered
Observations Weather Sunny,80's
Location See Figure 2,Site Map Surface GrassyField
Condition
ma)
c
o i- m
o `a5o co >
> L °' a o " MATERIAL DESCRIPTION
>»- --. a n,.n r 2 w °' REMARKS AND
w w ow '29 E E E m a? §o OTHER TESTS
0 &U a#
LEAN CLAY[CLI, low plasticity,rapid dilatancy, micaceous,mottled
brown,moist.
1
-560
5- _
Increase in moisture content
-
Grades to medium plasticity,slow dilatancy,trace angular basaltic gravel.
2 stiff,reddish brown,moist.
10
m �j
S '
N . xx'
. BASALT, highly weathered,very weak, 5-10%vesicles>2mm dia.,
o reddish brown.
x -
1- Increases to highly to moderately weathered, weak to moderately strong,
vi brown.
n-550 - x.
Test Pit terminated at a depth of 14.5'bgs on 6/4/2003 due to difficult
ao
15- -excavating conditions. -
a
a
J
J
0
CO
0
U) -
0
LL -
O
O
A I
,0
0
a
a
I- 20- -
y-
reo
a
,
0
a
m
Project: TTSD Alberta Rider Elementary School
Project Location: Tigard, Oregon Log of Test Pit
Project Number: 25695391.10001 TP-10-2003
Excavateds6/4/2003 Logged
ByBy
LenJDS Checked
Excavation 15.0 feet
Excavation 3.0 feet th of
VVidth of
Depth of BJD
ExcavationExcavation 13.0 feet
Equipment CExcavation Approximate
Case 9030 B Trackhoe
Contractor BEC Surface Elevation —562.0 feet MSL
Water Groundwater Not Encountered
Observations
Weather Sunny,80's
Location See Figure 2,Site Map Surface
Condition Grassy Field
o)
O i-- J N
w N N �' U o co N
a REMARKS AND
9- w °a� a n.� s MATERIAL DESCRIPTION 2~ °1
w 2 0') E m = `�° ' " OTHER TESTS
u) u)z 0 o P o
0 2ci aVk
% LEAN CLAY[CLI,low plasticity, rapid dilatancy,trace organics,
micaceous,medium stiff,mottled brown,moist.
—560 - % _
1 Grades to yellowish brown to brown
-
_
5 —
Grades to medium plasticity,slow dilatancy,trace gravel,stiff,reddish
brown,moist.
10— /lU�j
BASALT,highly weathered,very weak,5-10%vesicles>2mm dia., highly
x fractured,reddish brown,moist.
g—550 -
o x Grades to highly to moderately weathered,weak to moderately strong
, . .
d.
,, Test Pit terminated at a depth of 13.0'bgs on 6/4/2003 due to difficult
N excavating conditions.
C
a. 15—
Ir.
—
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ii
IL
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0
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U
0.
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a
c
am -
Q
[Project: TTSD Alberta Rider Elementary School
Project Location: Tigard, Oregon Log of Test Pit
Project Number: 25695391.10001 TP-11-2003
Dates) 6/4/2003 Logged
Excavated JDS Checked
gy g BJD
LeExcavation 15.0 feetth of pvation 3.0 feet of Depth of
Excavation 16.5 feet
Excavation Case 9030 B Trackhoe Excavation
Equipment Contractor BEC Approximate —558.0 feet MSL
Water Surface Elevation
Observations Groundwater Not Encountered
Weather Sunny,80's
Location See Figure 2,Site Map Surface
Condition Grassy Field
0)
a)
o FT JO co
h-.) o d >
m t a iin a MATERIAL DESCRIPTION ,c "' REMARKS AND
w�' o m E E E m N 0 w o OTHER TESTS
co• co1IIZ C7 0 0 0
0 mac) a`
LEAN CLAY[CLI,low plasticity,rapid dilatancy,trace organics,medium
stiff,mottled brown, moist.
� -
1
5—
/ _
Grades to medium plasticity,slow dilatancy,some angular basaltic gravel,
stiff,mottled reddish brown,moist.
—550
2
-
10—
j
% • N BASALT,highly weathered,very weak, 5-10%vesicles>2mm dia., highly
% N fractured,Fe,Cl,Mn filled fractures, reddish brown.
$ - `x
N `%
Q.. N%x%
H
t%
. %
x
0 •%%%N
0
N -
iil
x Grades to highly to moderately weathered, weak to moderately strong
15— —
—5
-
J
D x x x
0 Test Pit terminated at a depth of 16.5'bgs on 6/4/2003 due to difficult
k excavating conditions. _
id
Z —540 - -
S
0
a
,
a 20— —
—
a
t
0
a
m
Project: TTSD Alberta Rider Elementary School
Project Location: Tigard, Oregon Log of Test Pit
Project Number: 25695391.10001 TP-12-2003
Date(s) 6/4/2003 Logged
Excavated JDS Checked
By
BLey
BJD
Excavation ation 15.0 feet th of Width of 3.0 feet Depth of
Excavation Excavation 15.5 feet
Excavation Case 9030 B Trackhoe Excavation
Equipment BECApproximate
Water Contractor Sur —562.0 feet MSL
Surface Elevation
Observations Groundwater Not Encountered
Weather Sunny,80's
Location See Figure 2,Site Map Surface
Condition Grassy Field
ar
o U)
N
CV a�
m a �� o MATERIAL DESCRIPTION 9 d REMARKS AND
w tea) w E E E m ' °' c, OTHER TESTS
c/o Z C7 c o o
% LEAN CLAY[CL], low plasticity,rapid dilatancy,micaceous,trace
organics,medium stiff, mottled,moist.
—560 -
Grades to brown to brownish yellow
1
31.3
5—
2 Grades to medium plasticity,slow dilatancy, trace angular basaltic moist. g c gravel, 33.1 pH=5.7,Sulfates=
stiff,reddish brown,
5.56 mg/L, Chlorides=
0.629 mg/L
10—
g—550
BASALT,highly weathered,very weak, 5-10%vesicles<5mm dia., highly
fractured,Fe and Mn filled fractures, moist.
d
S
x„xxx
N _ _
m . Grades to highly to moderately weathered, weak to moderately strong
a- 15—
x M K Test Pit terminated at a depth of 15.5'bgs on 6/4/2003 due to difficult
- excavating conditions. -
CO
CO
0
v
LL -
O
0
N
U
a
20— —
C
0
a
0 0
a
URS�'
!Project: TTSD Alberta Rider Elementary School
Project Location: Tigard, Oregon Log of Test Pit
Project Number: 25695391.10001 TP-13-2003
Date(s) 8/4/2003 Logged
Excavated JDS Checked
By BJD
Length of 15.0 feet Width of By
Excavation Excavation 3.0 feet Depth of 15.0 feet
Excavation Excavation
Equipment Case 9030 B Trackhoe Excavation BEC
Contractor Approximate —551.0 feet MSL
•
Water Surface Elevation
Observations Groundwater Not Encountered
Weather Sunny,80's
Location See Figure 2,Site Map Surface
Condition Grassy Field
a) 0)
I
o 'U)
45 o m a�
a > REMARKS AND
w w o f E E m MATERIAL DESCRIPTION �,
2 a)c a) OTHER TESTS
0 V7 v)Z 0 O O a)N
Mo o-4t
LEAN CLAY[CL],low plasticity,rapid dilatancy,micaceous,trace
organics,stiff, mottled brown,moist.
—550 Project_
Grades to brown to brownish yellow
j -
1
5—
7
j -
Grades to medium plasticity,slow dilatancy,some angular
stiff,reddish brown,moist. ybasaltic gravels,
10-
-540 -
m /1:
No
. BASALT, highly weathered,very weak,highly fractured, Fe,Cl,Mn filled
• • fractures, 5-10%vesicles>2mm dia., reddish brown.
I
a
0
mxxx
Grades to moderately weathered,weak to moderately strong
0_ 15 x• = =
o Test Pit terminated at a depth of 15.0'bgs on 6/4/2003 due to difficult
excavating conditions.
J
03
m
-
-
W
LL
O
O
N
st'a
U
U
a.
F, 20—
Ix
a o
—530 l
r.
a
m
[Project: TTSD Alberta Rider Elementary School
Project Location: Tigard, Oregon Log of Test Pit
Project Number: 25695391.10001 TP-14-2003
- 'Date(s) 6/5/2003 Logged
Excavated By JDS Checked BJD
Length of By
Excavation 15.0 feet Width of 3.0 feet Depth of
Excavation Excavation 18.0 feet
Excavation Case 9030 B Trackhoe Excavation
Equipment Contractor BEC Approximate -554.0 feet MSL
Surface Elevation
Water Groundwater Not Encountered
Observations Weather Sunny,80's
Location See Figure 2,Site Map Surface
Condition Grassy Field
ca)
U)
O T O v)
J N
0 .2to ip
a REMARKS AND
wcl) o a E E MATERIAL DESCRIPTION -�
o OTHER TESTS
m m � A� o
In V)Z 0 O a
0
% LEAN CLAY[CL],low plasticity, rapid dilatancy,trace organics,medium
stiff,brown,moist.
Decrease in organics,mottled brown to yellowish brown
-550
C 1
5 -
Grades to medium plasticity,no dilatancy,trace angular gravel,stiff,
2 reddish brown,moist.
10- _
Degree of weathering decreases with depth,more gravel.
0
o
ri
d _
~o j
o_ 0 X BASALT, highly weathered,very weak,highly fractured, <5 vesicles
m X >2mm dia., Fe,Cl,Mn filled fractures,moist.
15- • - -
co
? • _
1 Grades to highly to moderately weathered, weak
m
O _
Xx%XX
lL X X X
Test Pit terminated at a depth of 18.0'bgs on 6/5/2003 due to difficult
S excavating conditions.
.210
0-
1-, 20- -
F- -
0
0
a.
O
O.
m
CL
Project: TTSD Alberta Rider Elementary School
Project Location: Tigard, Oregon Log of Test Pit
Project Number: 25695391.10001 TP-15-2003
Date(s) 6/5/2003 Logged
Excavated
By JDS Checked
ExcBy
Lenavation 15.0 feet th of
Width
dcavation 3.0 f •eet Depth of
IUD
Excavation Excavation 13.0 feet
Equipment Case 9030 B Trackhoe Excavation BEC Approximate
ContractorSurface Elevation '554.0 feet MSL
Water Groundwater Not Encountered
Observations
Weather Sunny,80's
Location See Figure 2,Site Map Surface
Condition Grassy Field
c o. a)O H o y
�,e a >
w w o w E E MATERIAL DESCRIPTION REMARKS AND
ct, in z N 0 o OTHER TESTS
0 �c3 n.`k
LEAN CLAY[CLI,low plasticity, rapid dilatancy,trace organics,
micaceous,medium stiff,some mottling,brown,moist.
•
-540
1 Grades to brown to brownish yellow
5-
-
-
Grades to
medium plasticity,no dilatancy,moist.
�C 2
10-
-
BASALT,highly weathered,very weak, highly fractured,Fe,CI, Mn filled
�, x fractures,reddish brown,moist.
-N
Grades to moderately to slightly weathered,moderately strong to strong
K• K K
. xx
Test Pit terminated at a depth of 12.0'bgs on 6/5/2003 due to difficult
N-530 excavating conditions.
0
co
a. 15-
CL -
J
J
p
0
r
m
iz
0 -
0
(N
0
Mia
'- 20-
-cc0
a.
o •
a
m
URS
APPENDIX B Dynamic Cone Penetrometer Test Logs
URS0:\25695391 TTSD Alberta Rider\TTSD Geotech.do610-JUL-03
DCP TEST DATA
Project: Tigard Tualatin School District
Date: 6/27/03
Feature: parking
Station: dcpl
0
I
-10
,
C
-C -
-30
Cs -
-40
-50-
1 10
100
CBR
.
I �
I i
(O M) TEST PROFILE (IN)
0
127
5
254 -
10
381 -- j 15
508 - 20
635 LEAN CLAY(CL)50.00"
25
762 --
30
889 - t 35
1016 - 40
1143 -
45
1270 50
L
DCP TEST DATA
Project: Tigard Tualatin School District Date: 6/27/03
Feature: parking Station: dcp2
0 r
l I
-10 (
c
-20_
- I
0 (
-
-50
1 10 100
CBR
O(MM) TEST PROFILE (IN)
0
127 - + 5
_ 254 - T 10
I
381 T 15
508 - + 20
635 1 LEAN CLAY(CL)50.00' - 25
i I
762 j - 30
889 _ 35
1016 T 40
1143 - 45
1270 50 i
1
DCP TEST DATA
Project: Tigard Tualatin School District bate: 6/27/03
Station: dcp3
Feature: parking
: .
0
-10- I
-20- I I,
-40-
-50
1 10 100
CBR
(O M) TEST PROFILE (IN)
0
127 T
5
254 - 10
381 t 15
i I I
508 - - 20
635 ± LEAN CLAY(CL)50.00" - 25
762
I - 30
I I
889 - 35
1016 T T 40
1143 - t 45
i
1270 ' 50
DCP TEST DATA
Project: Tigard Tualatin School District Date: 6/27/03
Feature: parking Station: dcp4
0
-10
;.=e -20
-30
-40
-50
1
10 100
CBR
I I
(MM) TEST PROFILE
(IN)
0 i 0
I I
127 - T 5
254 t + 10
381 - t 15
� I
508 - + 20
635 LEAN CLAY(CL)50.00" 25
762 30
' I
889 -" + 35
1016 t + 40
1143 -
45
1270 I50
DCP TEST DATA
Project: Tigard Tualatin School District Date: 6/27/03
Feature: parking Station: dcp5
0
-
' -2[
- - L
-30
C
-
40
-50
1 10 100
COR
(MM) TEST PROFILE (IN)
0 1 0
127 ± T 5
254 - T 10
381 T - 15
508 - 1
20
635 LEAN CLAY(CL)50.00" T 25
762 - + 30
889 35
1016 + 40
1143 - T 45
i
1270 50
L_
DCP TEST DATA
Project: Tigard Tualatin School District Date: 6/27/03
Feature: parking Station: dcp6
0
-10 F-1—,
C C- --'
' 20 I
46-
-30
-50
1 10 100
CBR
(MM) TEST PROFILE (IN)
0 0
127 j T 5
254 t - 10
381 rt - 15
I �
508 - - 20
635 -_ LEAN CLAY(CL)50.00' 1 25
762 - 30
889 1 - 35
10161, 40
1143 T 45
I
1270 50
: . DCP TEST DATA
Project: Tigard Tualatin School District Date: 6/27/03
Feature: parking Station: dcp7
0
1
-'10
� I
k7.-,e' -20- I-1 rt ..
0
-40-
1 10 100
CBR
(O M) TEST PROFILE (IN)
0
127 5
254 j
10
381 I - 15
508 - + 20
635 LEAN CLAY(CL)50.00" 25
762 j fi
_ 30
889 - T 35
1016 j 40
1143 *
45
1270 50
DCP TEST DATA
Project: Tigard Tualatin School District Date: 6/27/03
Feature: parking Station: dcp8
•
0
-10 f �----�
-
-317_
a _
-40
-50
1 10
100
CBR
I ?
0(MM) TEST PROFILE (IN)
0
127
5
254 10
381 15
508 20
635 ' LEAN CLAY(CL)50.00"
25
762 - _ 30
889 35
1016 t 40
1143
45
1270 50
DCP TEST DATA
Project: Tigard Tualatin School District Date: 6/27/03
Feature: parking Station: dcp9
0
-10 i
C
-2C
46.
-30_ ��1
a _ , `:
-40
_ I
-50
1
10 100
CBR
{
(O M) TEST PROFILE (IN)
0
127 - 5
254 - _ 10
I
381 - t 15 1
508 - 20
635 LEAN CLAY(CL)50.00 25
762 30
889 _ 35
1016 t _ 40
1
1143 - - 45
1270 50
1
DCP TEST DATA
Project: Tigard Tualatin School District Date: 6/27/03
Feature: parking Station: dcp10
0
- I J
-10-
J
'ter -20_
-30
-40
-50-
1 10 100
CBR
(MM) TEST PROFILE (IN)
0 0
127 - 5
254 - 10
381 - 15
508 -- 20
635 LEAN CLAY(CL)50.00° -- 25
762 - 30
889 35
1016 40
1143 45
1270 50
I II
DCP TEST DATA
Project: Tigard Tualatin School District Date: 6/27/03
Feature: parking Station: dcp11
0
-10
-40
1 10 100
CBR
(O M) TEST PROFILE (IN)
0
127 - 5
254 - 10
381 - i-- 15
508 - 20
635 - LEAN CLAY(CL)50.00" + 25
762 - - 30
889 T
35
1016 - T 40
1143 - 45
1270 50
APPENDIX C Laboratory Testing
URS0:\25695391 TTSD Alberta Rider\TTSD Geotech.doc\10-JUL-03
80
70
CH or OH
60
F.
W 50
0
z
"A" LINE
V 40
H
rn CL or OL
5
a 30
m
20
•
MH or OH
10
CL-ML ML Dr OL
0
0 10 20 30 40 50 60 70 80 90 100 110
LIQUID LIMIT,LL
Sample Depth Sample
Boring ID # (feet) Symbol Moisture LL PL PI Classification
B-02-2003 1 6-6.5 • 30.7 38 21 17 Lean Clay
B-02-2003 2 11-11.5 I 27.0 47 23 25 Lean Clay
eq
0
0
N
N
9
m
el
0
0
N
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1--I
0
J
a.
0
U,
w
W TTSD Alberta Rider Elementary School
Tigard, Oregon PLASTICITY CHART
25695391.10001
ct
URS
80
70
CH or OH
60
a
W 50
0
Z
"A"LINE
U 40
p
rn CL or OL
5
a. 30
CC
*•
A
MH or OH
10
CL-ML ML or OL
0
0 10 20 30 40 50 60
70 80 90 100 110
LIQUID LIMIT,LL
P
Sam le
Sample Deeeth
20
Boring ID t) Symbol Moisture LL PL PI Classification
TP-02-2003 1 4-4.5 • 31.7 44 20 24 Lean Clay
TP-02-2003 2 10-10.5 m 28.4 45 19 26 Lean Clay
o TP-05-2003 1 4-4.5 ♦ 29.4 39 21 18 Lean Clay
90
TP-05 2003 2 10-10.5 * 27.4 42 20 22 Lean Clay
ra-
0
0
N
O�.
Et
a
.
J
D
CO
^ CO
0
M
IR
LL
H
a
N
0
J
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c7
ceLu
w TTSD Alberta Rider Elementary School
Tigard, Oregon PLASTICITY CHART
a 25695391.10001
APPENDIX D Wetlands Review
CrURS \25695391 TTSD Alberta Rider\TTSD Geotech.doc\10-JUL-03
Memorandum
To: Bryan Duevel,URS
From: Noah Herlocker,URS
Date: July 8,2003
Subject: Wetland Determination for the proposed Alberta Rider Elementary School Project
Site
On June 5,2003 a URS wetland scientist conducted an onsite wetland determination at the
site of the proposed Alberta Rider Elementary School. The site is located in township 25,
range 1 west, and section 9 near the intersection of SW 130th Street and SW Bull Mt. Road in
Tigard, Oregon. This study examined all areas located within the property line for the future
elementary school,excluding the current residence that will be granted to the Tigard/
Tualatin School District in the future. The unstudied property is identified on Figure 2 as
"Future Expansion Area". This area was not examined at the request of the current residents.
The determination consisted of a preliminary review of the National Wetland Inventory'
(NWI)Beaverton Quadrangle(USFWS 1981) and the Washington County Soil Survey2
(USDA 1982). This review looked for mapped wetlands and/or the presence of hydric soils
in the project vicinity. A subsequent pedestrian survey was conducted to look for potential
wetland indicators identified in the 1987 Army Corps of Engineers Manual. The survey
relied upon the presence or absence of hydrophytic vegetation, hydric soil characteristics, and
primary and/or secondary hydrologic indicators to determine if wetlands were present on site.
The site is located on a hillside associated with Bull Mountain. From the northern property
line(SW Bull Mt. Rd.),the topography of the site includes an initial rise in elevation,heading
south to a summit. After this,the topography slopes downward to the south becoming
steeper toward the southern property line. The topography is steepest in the SE corner of the
property(Figure 2).
The north portion of the site, defined as the area rising from Bull Mt. Road to the highest
point on site, is a grassland community dominated by tall oatgrass (Arrhenatherum eliatus,
NI) and sweet vernalgrass (Anthoxanthum odoratum, FACU). The sub dominant vegetation
consisted of Douglas fir(Pseudotsuga menziesii, NI) along the western property line;beaked
hazelnut(Corylus cornuta, NI) along the northern property line; and a mix of herbaceous
vegetation including: velvetgrass (Holcus lanatus, FAC), common vetch(Viccia sativa, NI),
common dandelion (Taraxacum officianale, NI),oxeye daisy(Chrysanthemum
leucanthemum, NL),Himalayan blackberry(Rubus discolor, FACU),English ivy(Hedera
helix, NL), and Queen Anne's lace (Daucus carrota, NI).
In the southern portion of the site, defined as the area of land sloping down gradient and
south of the highest point on site, the vegetation was also dominated by tall oatgrass and
U.S.Fish and Wildlife Service(USFWS). Beaverton Quadrangle,OR [map]. 1:24,000. 15 Minute
Series. Portland, OR: USFWS,Region 1, 1981
2 Green, George L. 1982. Soil Survey of Washington County,Oregon. U.S.Department of
Agriculture, Soil Conservation Service in cooperation with the Oregon Agricultural Experiment Station
Page 1 of 2
LIRS
sweet vernal grass. The sub dominant vegetation, however,included a different assemblage
of plant species. These included Kentucky bluegrass(Poa pratensis, FAC), sheep sorrel
(Rumex acetosella, FACU+),tall fescue(Festuca arundinaceae, FAC-), orchard grass
(Dactylis glomerata, FACU), and English plantain(Plantago lanceolata, FAC).
u
The preliminary review of the NWI map showed no wetlands in the vicinity of the project
site. The soil survey mapped"Comelious and Kinton silt loams, 2 to 7 percent slopes"
onsite. This soil series is not hydric. No evidence of prolonged seasonal or permanent
surface inundation or soil saturation was observed. The topography of the site was steep
enough to prevent surface water from collecting in quantities necessary for the formation of
wetland characteristics.No hydrophitic vegetation was observed during the site visit. The
three species with a wetland facultative status (FAC)are highly cosmopolitan species that
inhabit a variety of soil types and moisture regimes. No wetland obligate status plant species
were observed.Where the topography appeared its flattest, soil pits were excavated. Soils
were examined in all four corners and the middle of the project site. Observed soils lacked
hydric soil indicators. No primary or secondary indicators of hydrology were observed.
Based on these observations,it was determined that no wetlands were present on the site of
the proposed Alberta Rider Elementary School.
t
Page 2 of 2