Report (2) 1
Geology I
Published geologic mapping indicates the site is mantled with residual soils produced from the weathering
of the underlying Columbia River Basalt (Madin, 2004). These residual soils typically consist of brown to
red-brown silt and clay soils of relatively high plasticity that exhibit relict structures of the weathered rock.
The weathering profile of the basalt grades from residual soil to hard rock with increasing depth within a
given flow. ,
PROJECT DESCRIPTION
We understand the new Art Rutkin Elementary School will be constructed under the 2016 Tualatin-Tigard I
School District Bond Program. Our project understanding is based on review of Schematic Design Plans
provided by KPFF, Inc., the project civil engineer, titled "Art Rutkin Elementary School, Tigard Tualatin
School District," dated March 26, 2019. The plans indicate the new school building and associated
improvements will occupy the western portion of the 20-acre site. The Site Plan,Figure 2,shows the planned
location of the new school and associated improvements. Review of the schematic design plans indicates
the new school will consist of a one-to two-story at-grade structure benched into the existing hillside. We
understand portions of the structure will have partially embedded walls and the maximum height of cuts and
fills to establish the finished floor elevation will be on the order of 10 and 15 ft, respectively. Structural
information provided by Catena Consulting Engineers, Inc.,the project structural engineer, indicates the new
school building will have maximum wall and column loads on the order of 3 kips/ftand 90 kips,respectively.
We anticipate the new school building will be designed in accordance with the 2012 IBC, which was
adopted by the 2014 OSSC.
Entrance to the campus and parking will be provided at the western margin of the proposed school building
and will be accessible from the west. We anticipate the height of cuts and fills required to establish finished
grades for the drive lanes, parking lots, and other ancillary improvements will be on the order of 5 to 20 ft.
Retaining structures, such as cantilever, mechanically stabilized earth (MSE),or soil nail walls, will likely be
required to maintain the finished site grades. We anticipate the entrance driveways and parking lots will be
paved with asphalt concrete (AC) and areas subjected to heavy traffic loads, such as trash enclosure areas,
will be paved with portland cement concrete (PCC). A soft-and hard-surfaced play area will be constructed
immediately south of the school within the southwest portion of the site. We understand a stormwater facility11
is proposed along the southern property boundary.
SUBSURFACE CONDITIONS 1
General
Subsurface materials and conditions at the site were investigated on December 13 and 14, 2018, and April
3 and 4, 2019,with 13 borings, designated B-1 through B-13, six test pits,designated TP-13 through TP-18,
and six Kessler Dynamic Cone Penetration (DCP) probes, designated DCP-1 through DCP-6. Six of the
borings were advanced to depths of about 6.5 ft below existing site grades in the proposed pavement areas,
five of the borings were advanced to depths of about 10.9 to 22.5 ft below existing site grades in the proposed
building footprint, and two of the borings were advanced to depths of about 29 to 32 ft below existing site
grades in the vicinity of the proposed retaining wall located near the north site boundary. The test pits were
excavated to depths of about 11.5 to 18.5 ft below existing site grades in the vicinity of the proposed retaining
walls located near the north and south site boundaries. The DCP probes were completed in the pavement
borings to a depth of about 4 ft below existing site grades. The approximate locations of the explorations
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completed for this investigation are shown on Figure 2. Logs of the borings and test pits are provided on
Figures 1 A through 19A. The field and laboratory programs conducted to evaluate the physical engineering
properties of the materials encountered in the explorations are described in Appendix A. The terms and
symbols used to describe the materials encountered in the explorations are defined in Tables 1A through 2A
and the attached legend.
Subsurface information from 12 test pit excavations, designated TP-1 through TP-12, completed by
GeoDesign, Inc., were included in our review of existing data for this project. The test pits were excavated
to depths of about 4 to 12.5 ft below existing site grades at the approximate locations shown on Figure 2.
Logs of the test pit excavations are provided in Appendix B for reference.
Sampling
Disturbed and undisturbed soil samples were obtained from the borings at 2.5-ft intervals of depth in the
upper 15 ft and 5-ft intervals below 15 ft. Disturbed soil samples were obtained using a 2-in.-outside-
diameter (O.D.) standard split-spoon sampler. Standard Penetration Tests (SPT) were conducted by driving
the samplers into the soil a distance of 18 in. using a 140-lb hammer dropped 30 in. The number of blows
required to drive the sampler the last 12 in. is known as the Standard Penetration Resistance,or SPT N-value.
SPT N-values provide a measure of the relative density of granular soils and the relative consistency of
cohesive soils. Relatively undisturbed soil samples were collected by pushing a 3-in.-O.D. Shelby tube into
the undisturbed soil a maximum of 24 in. using the hydraulic ram of the drill rig. The soil in the Shelby tubes
was extruded in our laboratory and Torvane shear strength measurements were recorded on selected
samples. In addition, core samples of basalt were obtained using HQ rock coring techniques.
Soils
For the purpose of discussion, the materials disclosed by our investigation have been grouped into the
following categories based on their physical characteristics and engineering properties:
1. Silty CLAY to Clayey SILT(Residual Soil)
2. Silty SAND(Decomposed Basalt)
3. BASALT(Columbia River Basalt)
•
The following paragraphs provide a description of the materials encountered in the explorations completed
by GRI for this investigation and a discussion of the groundwater conditions at the site.
1. Silty CLAY to Clayey SILT (Residual Soil). Residual soil consisting of silty clay to clayey silt was
encountered at the ground surface in all the explorations. The residual soil is derived from the weathering
of the underlying Columbia River Basalt and extends to depths of about 6.5 to 15 ft. In general, the soil is
brown with varying degrees of gray mottling and contains up to a trace of fine-grained sand and organics.
Gravel-to boulder-size fragments of decomposed basalt were encountered throughout the unit in exploration
TP-15. The relative consistency of the soil is medium stiff to very stiff based on SPT N-values of 4 to 21
blows/ft and Torvane shear-strength values of 0.25 to 0.60 tsf; however, an SPT N-value of 2 blows/ft
disclosed a 2.5-ft-thick zone of very soft to soft soil at the ground surface in explorations B-7 and B-11. The
natural moisture content of the soil ranges from 18 to 40%. Atterberg limits test results indicate the soil has
a liquid limit of 46 to 52% and plasticity index of 18 to 29%, see Figure 20A.
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One- dimensional consolidation testing was completed on samples of residual soil obtained at depths of
about 3.0 and 4.2 ft in explorations B-4 and B-10, respectively. Test results indicate the residual soils is
overconsolidated and exhibits a relatively low compressibility in the preconsolidated range of pressures and
moderate compressibility in the normally consolidated range of pressures,see Figures 21A and 22A.
Explorations B-1, B-2, B-5, B-7, B-8, and B-11 were terminated in residual soil at a depth of about 6.5 ft. I
2. Silty SAND(Decomposed Basalt). Decomposed basalt in the form of silty sand was encountered beneath
residual soil in explorations B-3, B-4, B-6, B-12, B-13, and TP-14 through TP-17. The thickness of the
decomposed basalt unit is variable, ranging from 1.5 to 7.5 ft thick,and extends to depths of about 10 to 17
ft. In general, the soil is green-gray to gray with rust staining and contains fine-to coarse-grained sand and
gravel-sized fragments of predominantly decomposed basalt. Green, white, pink, and red mineralization I
and relict rock structures are present throughout the unit. Our drilling for the project and our experience in
the site vicinity indicate this deposit usually contains gravel-to boulder-sized fragments of predominantly
decomposed basalt. The relative density of the silty sand is medium dense to very dense based on SPT N-
values of 15 to 74 blows/ft and is typically dense. The natural moisture content of the silty sand ranges from
26 to 44%.
3. BASALT (Columbia River Basalt). Extremely soft (RO) to hard (R4) basalt of the Columbia River Basalt
Group was encountered beneath silty clay to clayey silt(residual soil) in explorations B-9, B-10,TP-13, and
TP-18 and beneath silty sand (decomposed basalt) in explorations B-3, B-4, B-6, B-12, B-13, and TP-14
through TP-17. The basalt was encountered at depths of about 7.5 to 17 ft and extends to the maximum
depth explored of about 32 ft. In explorations B-6, B-12, and B-13, the basalt was cored below a depth of
about 12.5 to 28 ft. The quality of basalt,as measured by the degree of hardness and weathering,was highly
variable. Core recovery ranged from 30 to 70%. The basalt has some vesicles and open joints with clay
infilling, resulting in typical rock quality designations(RQD)of 0 to 10%. The joints and fractures displayed
some staining, and secondary mineralization was observed on some joint and fracture faces and in some
vesicles. Typically, the basalt is gray and black or brown and predominantly decomposed to decomposed
near the top of the unit and grades to slightly weathered with depth.
Explorations B-3, B-4, B-6, B-9, B-10, B-12, B-13, and TP-13 through TP-18 were terminated in basalt at
depths of about 11 to 32 ft.
Groundwater
Groundwater seepage was not encountered at the time of drilling in six of the borings completed using
hollow-stem auger drilling techniques and was not encountered at the time of excavation of the test pits. The
remaining seven borings were completed using mud-rotary drilling techniques, which do not allow an
accurate measurement of the groundwater level during drilling. Our review of U.S. Geological Survey
(USGS) groundwater data suggests the regional groundwater level at the site typically occurs at depth in the
highly fractured, hard basalt that underlies the site (Snyder, 2008). However, our experience in the project
vicinity indicates perched groundwater can occur in the residual soil and decomposed basalt that mantle the
site, particularly following periods of intense or prolonged precipitation.
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Infiltration Testing
On December 14, 2018, falling head infiltration tests were conducted in two boreholes designated I-1 and
1-2 at a depth of about 3 ft below existing site grades. The approximate locations of the infiltration tests are
shown on Figure 2, within the proposed stormwater facility footprint. The unfactored, field-measured
infiltration rates recorded at a specific depth within a specific soil unit are tabulated below. Details regarding
the infiltration testing methods are provided in Appendix A.
INFILTRATION TEST RESULTS
Depth of Average Infiltration
Boring Infiltration Test, ft Rate,in./hour Soil Classification
I-1 3.0 0.0 Clayey Silt to Silty CLAY
1 (Residual Soil)
1-2 3.0 p p Clayey Silt to Silty CLAY
(Residual Soil)
CONCLUSIONS AND RECOMMENDATIONS
General
' Subsurface conditions disclosed by the explorations completed for this investigation are consistent with
conditions encountered during previous investigations completed at the site. The explorations indicate the
site is mantled with residual soil underlain by decomposed basalt produced by the weathering of the
underlying Columbia River Basalt. Groundwater was not encountered at the time of exploration; however,
we anticipate perched groundwater may approach the ground surface at the site during the wet winter
months or following intense or prolonged precipitation.
In our opinion,foundation support for new structural loads can be provided by conventional spread and wall
foundations established in firm, undisturbed native soil or compacted structural fill. The primary
geotechnical considerations associated with construction of the new school and associated improvements
include the presence of fine-grained soils at the ground surface that are extremely sensitive to moisture
content; the potential for shallow, perched groundwater conditions;the potential for sheeting surface water
off the hillside; and the presence of shallow basalt. The following sections of this report provide our
conclusions and recommendations for use in the design and construction of the project.
1 Seismic Considerations
General. We understand the project will be designed in accordance with the 2012 IBC with 2014 OSSC
modifications. For seismic design, the 2012 IBC references the American Society of Civil Engineers (ASCE)
Document 7-10, Minimum Design Loads for Buildings and Other Structures (ASCE 7-10). A site-specific
seismic-hazard evaluation was completed for the project in accordance with the 2014 OSSC. Details of the
site-specific seismic hazard evaluation and the development of the recommended response spectra are
provided in Appendix C.
Code Background. The 2012 IBC and ASCE 7-10 seismic hazard levels are based on a Risk-Targeted
Maximum Considered Earthquake (MCER) with the intent of including the probability of structural collapse.
The ground motions associated with the probabilistic MCER represent a targeted risk level of 1% in 50 years
probability of collapse in the direction of maximum horizontal response with 5%damping. In general,these
risk-targeted ground motions are developed by applying adjustment factors of directivity and risk coefficients
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to the 2% probability of exceedance in 50 years, or 2,475-year return period, hazard-level (MCE) ground
motions developed from the 2014 USGS Unified Hazard Tool (USGS, 2014). The risk-targeted probabilistic
values are also subject to a deterministic limit. The code-based, ground-surface, MCER-level spectrum is
typically developed using the mapped bedrock spectral accelerations, Ss and Si,and corresponding site
coefficients, Fa and Fv,to account for site soil conditions.
Site Response. The ASCE 7-10 methodology uses two bedrock spectral response parameters, Ss and Si,
corresponding to periods around 0.2 and 1.0 second to develop the MCER response spectrum. To establish
the ground-surface MCER spectrum, these bedrock spectral coefficients are adjusted for site class using the
short- and long-period site coefficients, Fa and F,, in accordance with Section 11.4.3 of ASCE 7-10. The
design-level response spectrum is calculated as two-thirds of the ground-surface MCER spectrum.
The maximum horizontal-direction spectral response accelerations were obtained from the USGS Seismic
Design Maps for the coordinates of 45.4071° N latitude and 122.8454° W longitude. The Ss and Si
parameters identified for the site are 0.95 and 0.42 g, respectively, for Site Class B, or bedrock conditions. I
Based on our review of Section 20.4.2 of ASCE 7-10,the subsurface conditions disclosed by the explorations,
and the results of our site-specific seismic hazard evaluation, the soil profile at the site is representative of
Site Class C conditions. The recommended MCER- and design-level spectral response parameters for Site
Class C conditions are tabulated below and discussed in further detail in Appendix C.
RECOMMENDED SEISMIC DESIGN PARAMETERS(2012 IBC/2014 OSSC) I
�..,
Recommended
Seismic Parameter Value
Site Class C
MCER 0.2-Second Period 0.97 g
Spectral Response Acceleration, SMs
MCER 1.0-Second Period 0.58 g
Spectral Response Acceleration,SM1
Design-Level 0.2-Second Period 0.65 g
Spectral Response Acceleration, Sos
Design-Level 1.0-Second Period 0.39 g
Spectral Response Acceleration, Sol
Seismic Hazards. Based on the depth to groundwater at the site, it is our opinion the risk of liquefaction I
and/or cyclic softening at the site is low. Due to the relative consistency/density of the overburden soils and
the presence of shallow basalt, it is our opinion the risk of earthquake-induced slope instability is low. The
risk of damage by tsunami and/or seiche at the site is absent. The location of the Canby-Mollala Fault is
about 5 km east of the site(Personius et al., 2003); however,the USGS does not consider the Canby-Mollala
Fault to be an active, contributing source in their Probabilistic Seismic Hazard Analysis (PSHA). The USGS
considers the Portland Hills Fault, located about 17 km east of the site, to be the closest crustal fault source
contributing to the overall seismic hazard at the site. Unless occurring on a previously unmapped or
unknown fault, the risk of fault rupture at the site is low.
Earthwork
General. The fine-grained soils that mantle the site are sensitive to moisture,and perched groundwater may
approach the ground surface during the wet winter months. Therefore, it is our opinion earthwork can be
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completed most economically during the dry summer months,typically extending from June to mid-October.
It has been our experience that the moisture content of the upper few feet of the fine-grained soils will
' decrease during extended warm, dry weather. However, below this depth,the moisture content of the soil
tends to remain relatively unchanged and well above the optimum moisture content for compaction. As a
result,the contractor must use construction equipment and procedures that reduce disturbance and softening
of the subgrade soils. To minimize disturbance of the moisture-sensitive fine-grained soils, site grading can
be completed using track-mounted hydraulic excavators. The excavation should be finished using a smooth-
edged bucket to produce a firm, undisturbed surface. It may also be necessary to construct granular haul
roads and work pads concurrently with excavation to reduce subgrade disturbance. If the subgrade is
disturbed during construction, soft, disturbed soils should be overexcavated to firm soil and backfilled with
structural fill.
If construction occurs during wet-ground conditions, granular work pads will be required to protect the
underlying fine-grained subgrade and provide a firm working surface for construction activities. In our
opinion, a 12- to 18-in.-thick granular work pad should be sufficient to reduce subgrade disturbance by
lighter construction equipment and limited traffic by dump trucks. Haul roads and other high- density traffic
areas will require a minimum of 18 to 24 in. of fragmental rock, up to 6-in. nominal size, to reduce the risk
of subgrade deterioration. The use of a geotextile fabric over the subgrade may reduce maintenance during
construction.
As an alternative to the use of a thickened section of crushed rock to support construction activities and
protect the subgrade,the subgrade soils can be treated with cement. It has been our experience in this area
that treating the subgrade soils to a depth of 12 to 14 in.with about a 6 to 8% admixture of cement overlain
by 6 to 12 in. of crushed rock will support construction equipment and provide a good,all-weather working
surface.
Site Preparation. The ground surface within all building areas, paved areas,walkways,and areas to receive
structural fill should be stripped of existing vegetation, surface organics, and loose surface soils. We
anticipate stripping up to a depth of about 4 to 6 in.will likely be required within vegetated areas; however,
deeper grubbing may be required to remove brush and tree roots. All trees, brush, and surficial organic
material should be removed from within the limits of the proposed improvements. Excavations required to
remove brush and trees should be backfilled with structural fill. Organic strippings should be disposed of
off site or stockpiled on site for use in landscaped areas.
Following stripping or excavation to subgrade level,the exposed subgrade should be evaluated by a qualified
member of GRI's geotechnical engineering staff or an engineering geologist. Proof rolling with a loaded
dump truck may be part of this evaluation. Any soft areas or areas of unsuitable material disclosed by the
evaluation should be overexcavated to firm material and backfilled with structural fill. Due to the presence
of very soft to soft soils near the ground surface, it should be anticipated that some overexcavation of subgrade
will be required.
Site Grading. Final grading across the project should provide for positive drainage of surface water away
from exposed slopes to reduce the potential for erosion. Prior to placing pavement base course aggregate,
subgrade should be sloped to a minimum 0.5% slope to aid in drainage. Permanent cut and fill slopes
should be no steeper than 2H:1V(Horizontal to Vertical) and should be protected with vegetation to reduce
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the risk of surface erosion due to rainfall. Seeps or springs that emerge on cut slopes may require drainage
provisions depending on the actual conditions observed during construction. These provisions could include
French drains, drainage blankets, and subdrains (possibly placed in utility trenches) to collect and remove
water. More detailed information about site drainage is provided in the Site Drainage subsection of this
report.
Site Drainage. Due to site topography,there is a risk of surface water sheeting off the hillside during periods
of intense or prolonged precipitation. In our opinion, construction of a seepage cutoff trench to intercept
surface water and shallow, perched groundwater should be considered to reduce the risk of surface water
impacting the building and other associated improvements. To be most effective,the cutoff trenches should
be positioned uphill of improvements and in low areas on site and should be excavated to the top of the
underlying basalt rock. Typical cutoff trench drainage details are provided on Figure 3. The figure shows a
perforated drain pipe backfilled with clean, drain rock that has less than 2% passing the No. 200 screen
(washed analyses) and is placed within an envelope of a non-woven geotextile fabric to serve as a filter
between the drain rock and the adjacent soil. Bedding the pipe in at least 6 in. of drain rock and providing
a positive slope for the pipe to drain will reduce the future risk of silt and fine-grained sand accumulating in
the pipe. Water collected in perforated drains should be discharged into approved stormwater inlets by
solid, non-perforated piping. If significant groundwater seepage is encountered, it may be prudent to install
more than one perforated drain pipe. In our opinion,these drainage improvements will increase the overall
stability of the site.
GRI should review the final site drainage plans developed by the civil engineer once they become available
to evaluate the effectiveness of the site drainage system.
Excavation
General. We estimate excavations on the order of 5 to 20 ft will be required to establish final site grades,
and the depth of utility excavations may be on the order of 5 to 10 ft. The method of excavation and design
of excavation support are the responsibility of the contractor and subject to applicable local,state,and federal
safety regulations, including the current Occupational Safety and Health Administration (OSHA) excavation
and trench safety standards. The means, methods,and sequencing of construction operations and site safety
are also the responsibility of the contractor. The information provided below is for the use of our client and
should not be interpreted to mean we are assuming responsibility for the contractor's actions or site safety.
Groundwater Management. Depending on the time of year the work is completed, perched groundwater
may be encountered in the excavations. Groundwater seepage, running soil conditions, and unstable
excavation sidewalls or excavation subgrades, if encountered during construction, will require dewatering
of the excavation and sidewall support. The impact of these conditions can be reduced by completing
excavations during the summer months, when perched groundwater levels are lowest, and by limiting the
depths of the excavations.
We anticipate perched groundwater inflow, if encountered, can generally be controlled by pumping from
sumps. To facilitate dewatering, it will be necessary to overexcavate the base of the excavation to permit
installation of a granular working blanket. We estimate the required thickness of the granular working
blanket will be on the order of 1 ft, or as required to maintain a stable excavation base. The actual required
depth of overexcavation will depend on the conditions exposed in the excavations and the effectiveness of
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the contractor's dewatering efforts. The thickness of the granular blanket must be evaluated based on field
observations during construction. We recommend the use of relatively clean,free-draining material,such as
2-to 4-in.-minus crushed rock, for this purpose. The use of a geotextile fabric over the excavation base will
assist in subgrade stability and dewatering.
Temporary Excavations. The inclination of temporary excavation slopes will depend, in part,on the perched
groundwater conditions encountered at the time of construction and the contractor's ability to control these
conditions. In this regard, we anticipate temporary excavation slopes can be cut at 1 H:1 V to a maximum
depth of 15 ft if groundwater levels are maintained at least 2 ft below the bottom of the excavation. If the
excavation depth exceeds 15 ft,the temporary excavation slopes should be cut at 1.5H:1V or flatter. Flatter
slopes will be necessary if significant seepage conditions are encountered. Some minor amounts of
sloughing,slumping,or running of temporary slopes should be anticipated shortly after groundwater seepage
occurs. A blanket of relatively clean, well-graded crushed rock placed on the slopes may be required to
' reduce the risk of raveling-soil conditions if temporary excavation slopes encounter perched groundwater.
We recommend the use of relatively clean,free- draining material,such as 2-to 4-in.-minus crushed rock,for
this purpose. The thickness of the granular blanket should be evaluated based on actual conditions but
would likely be in the range of 12 to 24 in.
In our opinion, the short-term stability of temporary slopes will be adequate if surcharge loads due to
construction traffic, vehicle parking, material laydown, etc., are maintained an equal distance to the height
of the slope away from the top of the open cut. Other measures that should be implemented to reduce the
risk of localized failures of temporary slopes include: 1) using geotextile fabric to protect the exposed cut
slopes from surface erosion;2) providing positive drainage away from the tops and bottoms of the cut slopes;
3) constructing and backfilling walls as soon as practical after completing the excavation; 4) backfilling
overexcavated areas as soon as practical after completing the excavation;and 5) periodically monitoring the
area around the top of the excavation for evidence of ground cracking. It must be emphasized that following
these recommendations will not guarantee sloughing or movement of the temporary cut slopes will not
occur; however,the measures should serve to reduce the risk of a major slope failure. It should be realized,
however, that blocks of ground and/or localized slumps may tend to move into the excavation during
construction.
Utility Excavations. In our opinion, there are three major considerations associated with design and
construction of new utilities:
1) Provide stable excavation side slopes or support for trench sidewalls to minimize loss of
ground.
2) Provide a safe working environment during construction.
3) Minimize post-construction settlement of the utility and ground surface.
According to current OSHA regulations,the majority of the fine-grained soils encountered in the explorations
may be classified as Type B. In our opinion,trenches less than 4 ft deep that do not encounter groundwater
may be cut vertically and left unsupported during the normal construction sequence,assuming trenches are
excavated and backfilled in the shortest possible sequence. Excavations more than 4 ft deep should be
laterally supported or alternatively provided with side slopes of 1 H:1V or flatter. In our opinion, adequate
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lateral support may be provided by common methods, such as the use of a trench shield or hydraulic shoring
systems.
Drainage pipes can be installed at the base of select trenches to helpwith site drainage and reduce the risk
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of perched groundwater or surface water inflow concentrating in the trench backfill during the wet season.
The drainage pipe should consist of a 4-in.-diameter perforated PVC pipe wrapped in a non-woven geotextile
and placed in the granular backfill near the bottom of the trench. A utility pipe in a typical cutoff trench
detail is provided on Figure 3. The collected water should be discharged to approved stormwater inlets by
solid, non-perforated piping. I
Rock Excavation. We anticipate shallow basalt may be encountered in excavations completed to found the
new building additions, retaining structures, and/or in utility excavations. The hardness, jointing, and
weathering of the underlying basalt will be highly variable depending on location and depth. Based on our
observations during test-pit excavations,we anticipate it will be possible to complete excavation of zones of
highly fractured or weathered basalt by ripping with a large bulldozer and/or a large track-mounted hydraulic '
excavator equipped with a rock bucket and rock teeth. However, it should be anticipated that some rock
chipping, mechanical or chemical splitting, or blasting will be necessary to remove harder zones of less-
weathered and fractured rock, if encountered. Blasting may not be permitted at the site and should be
discussed with the project team prior to considering this method. Project plans, specifications,and bid items
should address the uncertainty associated with encountering basalt in excavations completed on site. At a
minimum, we recommend the project bid items include a unit price per cubic yard of rock excavation.
Structural Fill
General. We anticipate up to 15 ft of structural fill may be required to achieve finished floor elevation for
the structure and finished grades for the associated improvements. In general, structural fills should consist
of imported or on-site, organic-free soils and should extend a minimum horizontal distance of 5 ft beyond
the edge of new foundations and 1 ft beyond the limits of ancillary improvements, such as the edge of new
pavements. Where fills are to be placed on existing slopes steeper than about 5H:1V, the area to be filled
should be terraced or benched to provide a relatively level surface for fill placement. Typical benching
requirements are illustrated on Figure 4.
Onsite, Fine-Grained Fill. The use of on-site, fine-grained soils for structural fill material is typically limited
to the dry summer months, when the moisture content of these soils can be controlled to within about 3% 111
of optimum. However, the natural moisture content of the on-site soils will probably exceed the optimum
moisture content throughout the majority of the year; therefore, some aeration and drying will be required
to meet the requirements for proper compaction. The required drying can best be accomplished by
spreading the material in thin lifts and tilling. Drying rates are dependent on weather factors, such as wind,
temperature, and relative humidity. Fine-grained soils used as structural fill should be placed in 8-in.-thick
lifts (loose) and compacted with a segmented-pad or sheepsfoot roller to at least 95% of the maximum dry
density as determined by ASTM International (ASTM) D698. If fine-grained soils are not compacted at a
moisture content within about 3% of optimum,the specified density cannot be achieved and the fill material
will be relatively weak and possibly compressible.
On-site, fine-grained soils and site strippings free of debris may be used as fill in non-structural landscaped
areas. These materials should be placed at about 90% of the maximum dry density as determined by
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ASTM D698. The moisture contents of soils placed in landscaped areas are not as critical as the moisture
contents of fill placed in building and pavement areas, provided construction equipment can effectively
handle the materials.
Imported Granular Fill. During wet conditions, imported granular material would be most suitable for
' construction of the structural fills. Granular material, such as sand, sandy gravel, or fragmental rock with a
maximum size of up to 2 in.and less than 5% passing the No. 200 sieve(washed analysis)would be suitable
structural fill material. Granular fill should be placed in lifts and compacted with vibratory equipment to at
least 95% of the maximum dry density determined in accordance with ASTM D698. Appropriate lift
thicknesses will depend on the type of compaction equipment used. For example, if hand-operated vibratory
plate equipment is used, lift thicknesses should be limited to 6 to 8 in. If smooth-drum,vibratory rollers are
used, lift thicknesses up to 12 in. are appropriate,and if backhoe-or excavator-mounted vibratory plates are
used, lift thicknesses of up to 2 ft may be acceptable.
Cement-Amended Fill. As an alternative to importing granular fill, cement may be mixed with fine-grained
soils to facilitate fill placement during wet conditions. The amount of cement required will depend on the
moisture,clay,and organic contents of the soil and must be determined at the time of construction. Typical
admixtures of 5 to 8% cement, based on the dry weight of the treated soil, have been successfully
implemented in the project area. Cement treatment principally serves to hydrate excessive moisture and
significantly improves the strength properties of a fine-grained subgrade or structural fill. Treatment is
accomplished by spreading a measured quantity of cement onto the surface and tilling 12 to 16 in. into the
subgrade or structural fill lift using specialized equipment. The treated soils are subsequently compacted
with segmented-pad rollers and finished with graders and smooth, steel- drum vibratory rollers. Cement-
treated soils are typically cured 3 to 5 days to maximize their strength gain prior to being trafficked by
equipment or placement of granular base course.
' Utility Trench Backfill. All utility trench excavations within building, hardscape,and pavement areas should
be backfi lied with relatively clean, granular material, such as sand, sandy gravel, or crushed rock of up to
1 1I2-in. maximum size and having less than 5% passing the No.200 sieve(washed analysis). The bottom of
the excavation should be thoroughly cleaned to remove loose materials and the utilities should be underlain
by a minimum 6-in. thickness of bedding material. The granular backfill material should be compacted to
at least 95% of the maximum dry density as determined by ASTM D698 in the upper 5 ft of the trench and
at least 92% of this density below a depth of 5 ft. The use of hoe-mounted vibratory-plate compactors is
usually most efficient for this purpose. Flooding or jetting as a means of compacting the trench backfill
should not be permitted.
Areal Fill Settlement. We anticipate fills up to 10 ft in height will be placed in the southern half of the
building footprint to achieve final site grades. Areal settlement will occur due to placement of new fills and
consolidation of the underlying soils. Settlement studies were completed using the computer program
Settle3D by Rocscience, Inc. Based on our studies, we estimate the total consolidation settlement due to
placement of 10 ft of fill will be on the order of 1 in. It is our opinion that, at a minimum,settlement due to
primary consolidation should be allowed to occur prior to construction of overlying foundations, slab-on-
grade floors, and hardscapes and installation of utilities. We anticipate the majority of this settlement will
occur during placement of the fill; however,we recommend waiting at least 4 weeks following construction
of the design fill height to construct the overlying improvements.
G ®0 11
I
Foundation Support i
Structural information provided by Catena Consulting Engineers, Inc., the project structural engineer,
indicates the new school building will have maximum wall and column loads on the order of 3 kips/ft and
90 kips, respectively. In our opinion,the proposed structural loads can be supported on conventional spread
and wall footings in accordance with the following design criteria.
All footings should be established in firm, undisturbed, native soil or compacted structural fill. The base of
all new footings should be established at a minimum depth of 18 in. below the lowest adjacent finished
grade. The footing width should not be less than 24 in. for isolated column footings and 18 in. for wall
footings. Excavations for all foundations should be made with a smooth-edged bucket, and all footing
subgrades should be observed by a member of GRI's geotechnical engineering staff. Soft or otherwise
unsuitable material encountered at foundation subgrade level should be overexcavated and backfilled with ,
granular structural fill. Due to the presence of soft soils near the ground surface, it should be anticipated that
some overexcavation of subgrade may be required.
We anticipate soft soils and shallow basalt may be encountered in excavations completed to found the new
building additions. To provide uniform support,we recommend all foundations be underlain by a minimum
12-in. thickness of compacted crushed rock due to the potentially variable footing support conditions.
Relatively clean, 11n-or 3/4-in.-minus crushed rock is suitable for this purpose. In addition, large excavation
equipment or excavation methods,such as chipping,splitting,chemical rock breaking,or blasting,will likely
be required if basalt is encountered in foundation excavations. More detailed information about rock
excavation methods and techniques is provided in the Rock Excavation subsection of this report.
Footings established in accordance with these criteria can be designed on the basis of an allowable soil
bearing pressure of 3,000 psf. This value applies to the total of dead load and/or frequently applied live loads
and can be increased by one-third for the total of all loads: dead, live, and wind or seismic. We estimate
the total static settlement of spread and wall footings designed in accordance with the recommendations
presented above will be less than 1 in.for footings supporting column and wall loads of up to 90 kips and 3
kips/ft, respectively. Differential static settlements between adjacent, comparably loaded footings on similar
subgrade conditions should be less than half the total settlement.
Horizontal shear forces can be resisted partially or completely by frictional forces developed between the
base of the footings and the underlying soil and by soil passive resistance. The total frictional resistance
between the footing and the soil is the normal force times the coefficient of friction between the soil and the
base of the footing. We recommend an ultimate value of 0.40 for the coefficient of friction for footings cast
ongranular material. The normal force is the sum of the vertical forces (dead load plus real live load). If
additional lateral resistance is required, passive earth pressures against embedded footings can be computed
on the basis of an equivalent fluid having a unit weight of 250 pcf. This design passive earth pressure would
be applicable only if the footing is cast neat against undisturbed soil or if backfill for the footings is placed as
granular structural fill and assumes up to 1/2 in. of lateral movement of the structure will occur in order for
the soil to develop this resistance. This value also assumes the ground surface in front of the foundation is
horizontal, i.e., does not slope downward away from the toe of the footing, or has at least 4 ft of horizontal
distance from the embedded portion of the footing to the face of any permanent slope up to 3H:1V. For
foundations constructed on slopes up to 3H:1V, the passive pressure against the embedded portion of the
foundation should be reduced to 100 pcf.
G R` 12
1
I
Subdrainage/Floor Support
To provide a capillary break and reduce the risk of damp floors, slab-on-grade floors established at or above
adjacent final site grades should be underlain by a minimum 8 in.of free- draining,clean,angular rock. This
material should consist of angular rock such as 11 -to 3A-in.crushed rock with less than 2°Io passing the No.
' 200 sieve (washed analysis) and should be capped with a 2-in.-thick layer of compacted, 3/4-in.-minus
crushed rock to improve workability. The slab base course section should be placed in one lift and
compacted to at least 95% of the maximum dry density (ASTM D698) or until well-keyed. In our opinion,
' it is appropriate to assume a coefficient of subgrade reaction, k, of 175 pci to characterize the subgrade
support for point loading with 10 in. of compacted crushed rock beneath the floor slab. In areas where floor
coverings will be provided, or moisture-sensitive materials stored, it would be appropriate to also install a
vapor-retarding membrane. The membrane should be installed as recommended by the manufacturer.
We understand the building will be benched into the hillside and portions of the building will be established
below final site grades. In our opinion,structures such as floors and loading ramps that are established below
the final and existing site grades should be provided with a subdrainage system to reduce the potential for
hydrostatic pressure and the risk of groundwater entering through embedded walls and floor slabs. In
addition, a foundation drain should be installed around the perimeter of the building to collect water that
could potentially infiltrate beneath the foundations and should discharge to an approved storm drain. Typical
subdrainage details for embedded structures and footings are shown on Figure 5. The figure shows perimeter
subdrains to drain embedded walls and/or footings, and an interior granular drainage blanket beneath the
concrete floor slab, which is drained by a system of subslab drainage pipes. All groundwater collected
should be drained by gravity or pumped from sumps into the stormwater disposal facility. If the water is
pumped, an emergency power supply should be included to prevent flooding due to a power loss.
GRI should review the final subdrainage plans developed by the civil engineer for the building once they
become available to evaluate the effectiveness of the subdrainage system.
Retaining/Embedded Walls
General. Walls with a maximum height of about 10 to 15 ft will be required for construction of the partially
embedded lower level,and site retaining walls up to 20 ft in height will be required to retain finished grades
for the drive lanes, parking lots, and other ancillary improvements. We anticipate the embedded walls will
be cast-in-place and supported on the building foundations and the retaining walls will be conventional
cantilever walls, such as cast-in-place walls or segmented block walls, or soil nail walls. We should be
contacted if other types of retaining walls are to be considered for this project.
GRI should review the final plans developed by the wall designer once they become available and complete
global external stability analyses on representative cross sections of the planned retaining walls.
Lateral Earth Pressures. Design lateral earth pressures for retaining/embedded walls depend on the type of
construction, i.e.,the ability of the wall to yield. Possible conditions are: 1)a wall that is laterally supported
' at its base and top and therefore unable to yield to the active state; and 2)a retaining wall, such as a typical
cantilever or gravity wall, that yields to the active state by tilting about its base. A conventional basement
wall and cantilever retaining wall are examples of non-yielding and yielding walls, respectively.
I
G RD 13
I
For horizontal backfill,yielding and non-yielding walls may be designed on the basis of equivalent fluid unit
weights of 35 and 55 pcf, respectively. To account for seismic loading, the earth pressure should be
increased by 8 and 16 pcf for yielding and non-yielding walls, respectively,with horizontal backfill. For up
to a 3H:1V sloping backfill, yielding walls may be designed based on the basis of an equivalent fluid unit
weight of 55 pcf and should be increased by 23 pcf to account for seismic conditions. These earth pressures
assume the walls are fully drained, i.e., hydrostatic pressure cannot build up on the back of the wall. This
results in a triangular distribution with the resultant acting at 1I3H up from the base of the wall, where H is
the height of the wall in feet. Additional lateral loading due to surcharge loads can be evaluated using the
criteria shown on Figure 6. ,
The lateral earth pressure criteria presented above are appropriate if the retaining/embedded walls are fully
drained. Although the permanent groundwater level likely occurs at depth in the fractured basalt that
underlies the site, perched groundwater may occur within the shallow fine-grained soils and existing utility
trenches during periods of prolonged or intense precipitation. We recommend installation of a permanent
drainage system behind all the retaining/embedded walls. The drainage system can either consist of a
drainage blanket of crushed rock or continuous drainage panels between the retained soil/backfill and the
face of the wall. The drainage blanket should have a minimum width of 12 in. and consist of crushed drain
rock that contains less than 2% fines content (washed analysis). A typical drainage system for embedded
walls is shown on Figure 5. The drainage blanket or drainage panels should extend to the base of the wall,
where water should be collected in a perforated pipe and discharged to a suitable outlet,such as a sump or
approved storm drain. In addition, the wall design should include positive drainage measures to prevent
ponding of surface water behind the top of the wall.
Overcompaction of backfill behind walls should be avoided. Heavy compactors and large pieces of
construction equipment should not operate within 5 ft of any retaining wall to avoid the buildup of excessive
lateral earth pressures. Compaction close to the walls should be accomplished with hand-operated vibratory
plate compactors. Overcompaction of backfill could significantly increase lateral earth pressures behind
walls and cause damage to cast-in-place concrete retaining walls.
Conventional Walls. Foundation design and subgrade preparation for conventional, cast-in-place or
segmented block walls should conform to the recommendations provided in the Foundation Support section
of this report. We recommend embedding the toe of conventional retaining walls at least 1.5 ft below the
ground surface in front of the wall. For conventional walls constructed on a slope of up to 3H:1V, we
recommend the toe of the wall be provided a minimum of 2.5 ft of embedment. To provide more uniform
support, conventional retaining walls should be founded on a minimum 6-in.-thick section of compacted
crushed rock.
Permanent improvements will likely be located within the zone of wall backfill; therefore, we recommend
all conventional wall backfill, excluding the drainage blanket, consist of relatively clean, granular structural
fill with a maximum size of about 11/2 in. and not more than about 5% passing the No. 200 sieve (washed
analysis). Typical design values for crushed rock described above are a wet(total)density, yr,of 130 pcf; an
effective angle of internal friction, (I)',of 35°; and an effective cohesion, c', of 0 psf.
We recommend a minimum reinforcement length for segmented block walls of no less than 0.8 times the
height of retained backfill plus the equivalent height of uniformly applied surcharge pressure at the top of
G R 14
I
the backfill. The actual reinforcement length should be evaluated by the wall designer. It should be
understood that cantilever walls must undergo some lateral deformation to mobilize the active earth
I
pressures and foundation resistance or shear strength of the MSE reinforcement typically used in segmented
block walls. Based on our experience, lateral deformations on the order of about 1/2 and 1 in. are typical for
20-ft-high MSE and cast-in-place concrete walls, respectively. The wall designer should evaluate the potential
1 for lateral deformation of the selected wall design.
Soil Nail Walls. We anticipate a soil nail wall may be used to retain the planned cut near the northern
I property boundary. Soil nail walls can be designed with relatively steep, near-vertical faces using reinforced
shotcrete facing between the individual soil nails, which are typically installed in drilled holes and grouted
into place.
I
Soil nail walls typically have proprietary design and installation procedures developed by a specialty
contractor to satisfy a performance-based specification. However, soil nail walls should be designed,
I constructed, and tested in substantial conformance with the guidelines provided in the Federal Highway
Administration (FHWA) Soil Nail Walls Reference Manual (FHWA-NHI-14-007). Based on a review of the
subsurface information for the site,we anticipate soil nail installation would primarily encounter residual soil
and decomposed basalt. In our opinion, it is appropriate for preliminary planning to assume the following
soil properties for the soil nail design.
IPRELIMINARY SOIL PROPERTIES FOR SOIL NAIL DESIGN
Static Conditions Seismic Conditions
I
Moist Unit Moisture Effective Effective Stress Undrained
Soil Type Weight,pcf Content,% Friction Angle,0' Cohesion,psf Shear Strength,psf
Clayey SILT to Silty CLAY 120 30 26° 250 500
(Residual Soil)
SAND
(Decomp sed Basalt) 125 40 380 0 Same as Static
I It should be understood that a soil nail wall must undergo some lateral deformation to mobilize the shear
strength of the nails. Based on our experience, lateral deformations on the order of about 1/2 in. are typical
for a 20-ft-high soil nail wall. The wall designer can consider stressing the soil nails to reduce wall
Ideformation.
Pavement Design
' We anticipate the bus loop pavement will be subjected to bus, automobile, and light truck traffic, and the
parking areas will be subjected primarily to automobile and light truck traffic, with occasional heavy truck
traffic. We anticipate the majority of the site will be paved with AC pavement; however,areas subjected to
I repeated heavy-truck traffic, such as trash-enclosure and service areas, may be paved with PCC pavement.
Traffic estimates for the roadways and parking areas are presently unknown.
1 Based on our experience with similar projects and subgrade soil conditions, we recommend the following
pavement sections.
I
I
G R D 15
111
RECOMMENDED AC PAVEMENT SECTIONS
Type Traffic LoadingCRB AC
Pavement
Thickness,in. Thickness,in.
AC Areas Subject to School-Bus 14 5
Traffic(Bus Loop)
Areas Subject to Primarily
AC Automobile Traffic(Service Road 12 4
and Vehicle Drive Lanes)
AC Areas Subject to Automobile 8 3
Parking(Parking Stalls)
111
Areas Subject to Repeated
PCC Heavy Truck Traffic(Trash 6 6
Enclosure and Service Areas)
Note: The recommended pavement sections should be considered minimum thicknesses and underlain
by a woven geotextile fabric.
It should be assumed that some maintenance will be required over the life of the pavement(15 to 20 years).
The recommended pavement sections are based on the assumption that pavement construction will be
accomplished during the dry season and after construction of the building has been completed. If wet-
weather pavement construction is considered, it will likely be necessary to increase the thickness of crushed-
rock base (CRB) course to support construction equipment and protect the subgrade from disturbance. The
indicated sections are not intended to support extensive construction traffic, such as fork lifts, dump trucks
and concrete trucks. Pavements subject to construction traffic may require repair.
For the above-indicated sections,drainage is an essential aspect of pavement performance. We recommend
all paved areas be provided positive drainage to remove surface water and water within the base course.
This will be particularly important in cut sections or at low points within the paved areas, such as at catch
basins. Effective methods to prevent saturation of the base course materials include providing weep holes in
the sidewalls of catch basins, subdrains in conjunction with utility excavations, and separate trench drain
systems. To ensure quality materials and construction practices,we recommend the pavement work conform
to Oregon Department of Transportation standards.
Prior to placing base course materials, all pavement areas should be proof rolled with a fully loaded, 10-y
dump truck. Any soft areas detected by the proof rolling should be overexcavated to firm ground and
backfilied with compacted structural fill.
Provided the pavement section is installed in accordance with the recommendations provided above, it is
our opinion the site-access areas will support infrequent traffic by an emergency vehicle having a gross
vehicle weight(GVW) of up to 75,000 lbs. For the purposes of this evaluation, "infrequent"can be defined
as once a month or less.
On-Site Disposal of Stormwater
The unfactored, field-measured infiltration rate for the residual soils that mantle the site is 0 in/hour;
therefore, it is our opinion the near-surface fine-grained soils do not meet the requirements for on-site
stormwater disposal.
G rUID 16
1
1
Considerations for Adjacent Property
We understand the project team would like to consider stockpiling spoils from on-site excavations on the
' property located immediately east of the project site. For the purpose of this report, the project site is
designated Lot 1 and the property located immediately east of Lot 1 is designated Lot 2. In our opinion, any
spoils stockpiled on Lot 2 should be prepared, placed, and compacted as structural fill in accordance with
the recommendations provided in the Structural Fill section of this report. The ground surface in the
stockpiled area should be stripped of existing vegetation, surface organics, and loose surface soils in
accordance with the recommendations provided in the Earthwork section of this report. Consideration
should be given to the location and dimensions of the stockpile and the time and effort required to strip the
ground surface of vegetation and place the excavation spoils as structural fill. In our opinion, it would be
' prudent to discuss stockpiling excavation spoils on Lot 2 with the property owner prior to considering this
option.
DESIGN REVIEW AND CONSTRUCTION SERVICES
We welcome the opportunity to review and discuss construction plans and specifications for this project as
they are being developed. In addition,GRI should be retained to review all geotechnical-related portions of
the plans and specifications to evaluate whether they are in conformance with the recommendations
provided in our report. To observe compliance with the intent of our recommendations,the design concepts,
and the plans and specifications, we are of the opinion that all construction operations dealing with
earthwork and foundations should be observed by a GRI representative. Our construction-phase services
will allow for timely design changes if site conditions are encountered that are different from those described
in our report. If we do not have the opportunity to confirm our interpretations, assumptions, and analyses
during construction, we cannot be responsible for the application of our recommendations to subsurface
conditions different from those described in this report.
LIMITATIONS
This report has been prepared to aid the architect and engineer in the design of this project. The scope is
limited to the specific project and location described herein, and our description of the project represents
our understanding of the significant aspects of the project relevant to the design and construction of the new
foundations and floors. In the event any changes in the design and location of the project elements as
outlined in this report are planned, we should be given the opportunity to review the changes and modify
or reaffirm the conclusions and recommendations of this report in writing.
The conclusions and recommendations submitted in this report are based on the data obtained from the
' explorations made at the locations indicated on Figure 2 and other sources of information discussed in this
report. In the performance of subsurface investigations, specific information is obtained at specific locations
at specific times. However, it is acknowledged that variations in soil conditions may exist between
exploration locations. This report does not reflect any variations that may occur between these explorations.
The nature and extent of variation may not become evident until construction. If during construction,
subsurface conditions differ from those encountered in the explorations, we should be advised at once so
that we can observe and review these conditions and reconsider our recommendations where necessary.
1
G RO ,7
1
Please contact the undersigned if you have any questions.
' Submitted for GRI,
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' A. Wesley Spang, PhD, PE, GE Nicholas M. Hatch, PE Marissa Rauthause, EIT
Principal Senior Engineer Engineering Staff
This document has been submitted electronically.
I
References
ASCE 7 Hazard Tool,2017-2018,accessed 1/3/19 from ASCE website:httpsJ/asce7hazardtool.online/.
Madin,I. P.,2004, Preliminary digital geologic compilation map of the greater Portland urban area,Oregon:Oregon Department of
Geology and Mineral Industries,Open-File Report 0-04-02,scale 1:24,000.
Personius,S.F., Dart,R. L.,Bradley, Lee-Ann,and Haller,K.M.,2003,Map and data for Quaternary faults and folds in Oregon: U.S.
Geological Survey Open-File Report 03-095.
Snyder, D. T., 2008, Estimated depth to ground water and configuration of the water table in the Portland, Oregon area: U.S.
Geological Survey Scientific Investigations Report 2008-5059,40 p.
' U.S.Geological Survey(USGS), Unified hazard tool,Conterminous U.S.2014(v4.0x),accessed 01/10/19 from USGS website:
https://earthquake.usgs.gov/hazards/interactiveL
U.S.Geological Survey,2018, U.S.Seismic Design Maps lookup by latitude,longitude,accessed 01/10/19 from USGS website:
httpsJ/earthquake.usgs.gov/designmaps/us/application.php.
I
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I GRANULAR MATERIAL(2 IN.MAX.)WITH
LESS THAN 5%PASSING THE NO.200
SIEVE(WASHED ANALYSIS)
I
UTILITY PIPE
MAY BE PLACED IN �•'i!.i•'i!ti•
t000..,yV.;
CUTOFF TRENCH i�y��044.
loti
410,
/ 0114
I le
4- '�/�
�I.N.
%4g Y
I n
I
4-IN.-DIAMETER PERFORATED DRAIN PIPE,
SLOPE TO DRAIN
I
I
I
I G RD
TIGARD-TUALATIN SCHOOL DISTRICT
ART RUTKIN ELEMENTARY SCHOOL
I CUTOFF TRENCH
DRAINAGE DETAIL
I
APR.2019 JOB NO.5970-K FIG.3
1
CUT SLOPE ,
EXISTING GROUND SURFACE
1��
2(MIN.)
FILL SLOPE
4 FT(MAX.)
y �
BENCHES(TYP.)
5 FT(MIN.)
1
TIGARD-TUALATIN SCHOOL DISTRICT ,
G RD
ART RUTKIN ELEMENTARY SCHOOL
TYPICAL DETAIL FOR 1
FILLING ON SLOPES
APR.2019 JOB NO.5970-K FIG.4
I
I
II
I 3/4-IN.-MINUS CRUSHED ROCK WITH
' SEAL WITH ON-SITE
LESS THAN 5°(°PASSING NO.200 SIEVE
IMPERVIOUS MATERIAL (WASHED ANALYSIS)
SLOPE TO DRAIN
a, P .
•
//// • '
/ 2 IN. _ CONCRETE SLAB
1 I
• n VARIES VAPOR-RETARDING MEMBRANE SYSTEM
to 4 (2 IN.MIN.) 81N.(MIN.) (SEE NOTE 1)
•
T v
• ° VARIES(2 IN.MIN.)
GRANULAR BACKFILL COMPACTED 1 FT \
TO ABOUT 95%OF THE MAXIMUMI I (MIN.) SEE DETAIL'A'FOR TYPICAL
DRY DENSITY AS DETERMINED BY ROCK OF UP TO 2-IN.SIZE WITH 4-IN.-DIAMETER PERFORATED DRAIN PIPES
ASTM D SIT a UNDERSLAB RECOMMENDATIONS NOT MORE THAN 2%PASSING THE
NO.200 SIEVE(WASHED ANALYSIS) ARE TYPICALLY PLACED ON 20-FT CENTERS
AND SLOPED TO DRAIN(SEE NOTE 2)
I TEMPORARY
CONSTRUCTION . L DETAIL 'A'
SLOPE f
NOT TO SCALE
O °
11/2 To3/4 GRAVEL WITH LESS THAN
2%PASSING THE NO.200 SIEVE
I (WASHED ANALYSIS)
\\ UNDERSLAB DRAIN
4-IN.-DIAMETER PERFORATED PLASTIC
I DRAIN PIPE,SLOPE TO DRAIN NOTES:
1) A VAPOR-RETARDING MEMBRANE SYSTEM IS RECOMMENDED FOR
MOISTURE-SENSITIVE AREAS AND SHOULD BE INSTALLED IN
ACCORDANCE WITH MANUFACTURER'S RECOMMENDATIONS.
I2) INTERNAL 4-IN.-DIAMETER PERFORATED DRAIN PIPES ARE TYPICALLY
PERIMETER DRAIN NOT NECESSARY IN THOSE AREAS WHERE THE FINISH FLOOR WILL BE
ABOVE EXISTING SITE GRADES.
I
I
I G ED TIGARD-TUALATIN SCHOOL DISTRICT
ART RUTKIN ELEMENTARY SCHOOL
I TYPICAL SUBDRAINAGE
DETAILS
IAPR.2019 JOB NO.5970-K FIG.5
1
1 X=mH )
LINE LOAD,Qr For STRIP LOAD,ri
fi / 13
/3/2
n
Z=nH P
i 11, IMIFF Form S.0.4:
II T ah = Qt 0.2n H
H H (0.16+n')'
I 11, Form> 0.4:
7 .SINPCOS2a(n
ah a _ QL 1.28mn/ h H (m +n ) (/3 in radians)
I
iLINE LOAD PARALLEL TO WALL STRIP LOAD PARALLEL TO WALL
I < X=mH >
POINT LOAD,Qp
I
n ^
I Z=nH 1M Form 5 0.4:
p1llE__ 1 liW1111-N oh = Qp 0.28n'
H Mr H' (0.16+n2)3
V, For m>0.4:
Qp 1.77m2n'
I i ah ah =
H' m'+n')'
I
a'h=ah COS2(1.18) NOTES:
II 1/ all1. THESE GUIDELINES APPLY TO RIGID WALLS WITH POISSON'S
® i O RATIO ASSUMED TO BE 0.5 FOR BACKFILL MATERIALS.
� 2. LATERAL PRESSURES FROM ANY COMBINATION OF ABOVE
IOr all LOADS MAY BE DETERMINED BY THE PRINCIPLE OF SUPERPOSITION.
X=mH >
DISTRIBUTION OF HORIZONTAL PRESSURES
1
VERTICAL POINT LOAD CJ R 11
TIGARD-TUALATIN SCHOOL DISTRICT
ART RUTKIN ELEMENTARY SCHOOL
S SURCHARGE-INDUCED
II LATERAL PRESSURE
APR.2019 JOB NO.5970-K FIG.6
I
APPENDIX A
FIELD EXPLORATIONS AND LABORATORY TESTING
FIELD EXPLORATIONS
Subsurface materials and conditions at the site were investigated on December 13 and 14, 2018, and April
3 and 4, 2019, with 13 borings, designated B-1 through B-13, six test pits,designated TP-13 though TP-18,
and six Kessler Dynamic Cone Penetration (DCP) probes, designated DCP-1 through DCP-6. The
approximate locations of the explorations completed for this investigation are shown on Figure 2. Logs of
the borings and test pits are provided on Figures 1A through 16A. The field exploration work was
coordinated and documented by an experienced member of GRI's geotechnical engineer staff, who
maintained a log of the materials and conditions disclosed during the course of work.
Borings
Borings, designated B-1 through B-13, were advanced to depths of about 6.5 to 32 ft below existing site
grades. Seven borings were completed with mud-rotary drilling techniques,and six borings were completed
with hollow-stem auger drilling techniques. The borings were completed using a CME 850 track-mounted
drill rig provided and operated by Western States Soil Conservation, Inc., of Hubbard, Oregon. Disturbed
samples of soil and decomposed rock were typically obtained from the borings at 2.5-ft intervals of depth in
the upper 15 ft and at 5-ft intervals below this depth. Standard Penetration Tests (SPT) were conducted at
the time of sampling by driving the sampler into the soil a distance of 18 in. using a 140-lb hammer dropped
30 in. The number of blows required to drive the sampler the last 12 in.is known as the Standard Penetration
Resistance, or SPT N-value. Samples obtained from the borings were placed in airtight jars and returned to
our laboratory for further classification and testing. In addition, relatively undisturbed soil samples were
collected by pushing a 3-in.-0.D. Shelby tube into the undisturbed soil a maximum of 24 in. using the
hydraulic ram of the drill rig. The soil in the Shelby tubes was extruded in our laboratory and Torvane or
undrained shear strength measurements were recorded. Where drilling refusal was encountered within the
depth of interest,samples of basalt were obtained using HQ rock coring techniques. The core samples were
placed in boxes and returned to our laboratory for further examination and testing.
Logs of the borings are provided on Figures 1A through 13A. Each log presents a descriptive summary of
the various types of materials encountered in the boring and notes the depths at which the materials and/or
characteristics of the materials change. To the right of the descriptive summary, the numbers and types of
�\ samples are indicated. Farther to the right, SPT N-values are shown graphically, along with the natural
moisture contents,Torvane shear strength values,and percent passing the No.200 sieve,where applicable.
The terms and symbols used to describe the materials encountered in the borings are defined in Tables 1 A
and 2A and the attached legend. A photograph of the core boxes is provided on Figure 23A.
Test Pits
Test pits, designated TP-13 through TP-18,were advanced to depths of about 11.5 to 18.5 ft using a CAT
326F excavator provided and operated by Benchmark Contracting, Inc.,of Lake Oswego,Oregon. Torvane
shear-strength values were obtained in test pit sidewalls where the material consisted of fine-grained soils.
Logs of the test pits are provided on Figures 14A through 19A. Each log presents summary of the various
R
G R U A-1
types of materials encountered in the test pits and notes the depth at which the materials and/or characteristics
of the materials change. To the right of the summary,Torvane shear-strength values are shown graphically.
The terms and symbols used to describe the materials encountered in the test pits are defined in Tables 1 A
and 2A and the attached legend. Photographs of the test pits were taken following completion and are111
provided on Figures 24A and 25A.
DCP Probes
Six DCP probes, designated DCP-1 through DCP-6, were advanced to a depth about 3 ft below the ground
surface using a Kessler DCP manufactured by KSE Testing Equipment. The DCP tests were completed in
accordance with ASTM International (ASTM) D6951 by driving a 5/8-in.-diameter steel rod with a cone tip
into the soil using a 17.6-lb sliding hammer dropped a fixed height of 22.6 in. The number of blows required
to drive the probe approximately 5 cm (2 in.) was recorded to depths ranging from 918 to 936 mm (3 to 3.111
ft). The DCP blow counts were used to estimate a California bearing ratio(CBR)value for the in-situ subgrade.
Infiltration Testing
On December 14, 2018, falling head infiltration tests were conducted in two boreholes, designated I-1 and
1-2,at a depth of about 3 ft below existing site grades. The borehole was blind-drilled to the test depth using
a 4-in.-diameter hand auger provided and operated by GRI. The approximate locations of the infiltration
tests are shown on Figure 2. The unfactored, field-measured infiltration rates recorded at a specific depth
within a specific soil unit are tabulated below.
Depth of Average Infiltration 111
Boring Infiltration Test, ft Rate, in./hour Soil Classification
I-1 3 0 Clayey SILT to Silty CLAY
(Residual Soil)
1-2 3 0 Clayey SILT to Silty CLAY
(Residual Soil)
The falling head infiltration tests were completed in general conformance with the City of Portland 2016
Stormwater Management Manual (SMM), using the encased falling head method outlined in Section 2.3.6
of the manual. The infiltration tests were completed inside a PVC pipe, which was embedded a couple of
inches below the drilled depth and filled with water to a height of approximately 1 ft above the drilled depth.
After soaking, infiltration testing was conducted by re-establishing the water level in the pipe to the target
height and recording the drop in water level over 1 hour or until the water completely drained, whichever
occurred first. Where necessary,the infiltration test was repeated until consecutive tests showed little or no
change in infiltration rate.
LABORATORY TESTING
General
The samples obtained from the borings were examined in our laboratory,where the physical characteristics
of the samples were noted and the field classifications modified where necessary. At the time of
classification, the natural moisture content of each sample was determined. Additional testing included
Torvane shear strength, dry unit weight measurements, Atterberg limits determinations, one-dimensional
consolidation tests,and grain-size analyses. A summary of the laboratory test results is provided in Table 3A.
The following sections describe the testing program in more detail. I
GR
A-2
1
INatural Moisture Content
Natural moisture content determinations were made in conformance with ASTM D2216. The results are
Isummarized on Figures 1A through 11A and in Table 3A.
Torvane Shear Strength
The approximate undrained shear strength of fine-grained soils was determined using a Torvane shear device.
t The Torvane is a hand-held apparatus with vanes that are inserted into the soil. The torque required to fail
the soil in shear around the vanes is measured using a calibrated spring. The results of the Torvane shear
11,
strength tests are summarized on Figures 4A and 10A
Undisturbed Unit Weight
IIThe unit weight, or density, of undisturbed soil samples was determined in the laboratory in
conformance with ASTM D2937. The results are summarized on Figures 4A and 10A and in Table 3A.
Atterberg Limits
Atterberg limits testing was performed on two samples of residual soil in conformance with ASTM D4318.
IThe test results are summarized on the Plasticity Chart, Figure 12A, Figures 5A and 6A,and in Table 3A.
One-Dimensional Consolidation
One-dimensional consolidation tests were performed in conformance with ASTM D2435 on relatively
undisturbed soil samples extruded from Shelby tubes. This test provides data on the compressibility of
underlying fine-grained soils, necessary for settlement studies. The test results are summarized on Figures
13A and 14A in the form of a curve showing percent strain versus applied effective stress. The initial dry
I unit weight and moisture content of the sample are also shown on the figures.
Grain-Size Analysis
11
Washed-Sieve Method. To assist in classification of the soils, samples of known dry weight were washed
over a No. 200 sieve. The material retained on the sieve was oven-dried and weighed. The percentage of
li material passing the No. 200 sieve was then calculated. The results are summarized on Figures 2A, 3A,4A,
and 10A, and in Table 3A.
,1
I
•1
I
1
i G R 1 1 A-3
I
IITable 1A
iGUIDELINES FOR CLASSIFICATION OF SOIL
I Description of Relative Density for Granular Soil
Standard Penetration Resistance
Relative Density (N-values),blows per ft
1 very loose 0-4
loose 4- 10
medium dense 10-30
I dense 30-50
very dense over 50
1 Description of Consistency for Fine-Grained(Cohesive)Soils
Standard Penetration Torvane or
I Resistance(N-values), Undrained Shear
Consistency blows per ft Strength,tsf
very soft 0-2 less than 0.125
I soft 2-4 0.125-0.25
medium stiff 4-8 0.25-0.50
stiff 8- 15 0.50-1.0
iti verystiff 15-30 1.0-2.0
hard over 30 over 2.0
IGrain-Size Classification Modifier for Subclassification
Boulders: Primary Constituent Primary Constituent
1 >12 in. SAND or GRAVEL SILT or CLAY
Cobbles: Adjective Percentage of Other Material(by weight)
3-12 in. trace: 5-15 (sand,gravel) 5-15(sand,gravel)
Gravel: some: 15-30(sand,gravel) 15-30(sand,gravel)
1/4-3/4 in. (fine) sandy,gravelly: 30-50(sand,gravel) 30-50(sand,gravel)
3/4-3 in. (coarse)
I Sand: trace: <5 (silt,clay)
No.200 No. 40 sieve(fine) Relationship of clay and
No.40-No. 10 sieve(medium) some: 5-12 (silt,clay) silt determined by
No. 10-No.4 sieve(coarse) silty, clayey: 12-50(silt,clay) plasticity index test
ISilt/Clay:
pass No. 200 sieve
I
I G Rp
I
1
Table 2A I
GUIDELINES FOR CLASSIFICATION OF ROCK
1
Relative Rock Weathering Scale
Term Field Identification
Fresh Crystals are bright. Discontinuities may show some minor surface staining. No discoloration in rock fabric.
Slightly Rock mass is generally fresh. Discontinuities are stained and may contain clay. Some discoloration in rock
Weathered fabric. Decomposition extends up to 1 in.into rock.
Moderately Rock mass is decomposed 50%or less. Significant portions of rock show discoloration and weathering
Weathered effects. Crystals are dull and show visible chemical alteration. Discontinuities are stained and may contain
secondary mineral deposits.
Predominantly Rock mass is more than 50%decomposed. Rock can be excavated with geologist's pick. All
Decomposed discontinuities exhibit secondary mineralization. Complete discoloration of rock fabric. Surface of core is
friable and usually pitted due to washing out of highly altered minerals by drilling water.
Decomposed Rock mass is completely decomposed. Original rock"fabric"may be evident. May be reduced to soil with
hand pressure.
Relative Rock Hardness Scale
Hardness Approximate Unconfined
Term Designation Field Identification Compressive Strength11
Extremely RO Can be indented with difficulty by thumbnail. May be < 100 psi
Soft moldable or friable with finger pressure.
Very R7 Crumbles under firm blows with point of a geology pick. 100-1,000 psi
Soft Can be peeled by a pocket knife and scratched with
fingernail.
Soft R2 Can be peeled by a pocket knife with difficulty. Cannot be 1,000-4,000 psi
scratched with fingernail. Shallow indentation made by firm
blow of geology pick.
Medium R3 Can be scratched by knife or pick. Specimen can be 4,000-8,000 psi
Hard fractured with a single firm blow of hammer/geology pick. 11
Hard R4 Can be scratched with knife or pick only with difficulty. 8,000-16,000 psi
Several hard hammer blows required to fracture specimen.
Very R5 Cannot be scratched by knife or sharp pick. Specimen > 16,000 psi
Hard requires many blows of hammer to fracture or chip.
Hammer rebounds after impact.
in
RQD and Rock Quality 1.
Relation of RQD and Rock Quality Terminology for Planar Surface
RQD(Rock Description of Bedding Joints and Fractures Spacing
Quality Designation),% Rock Quality Laminated Very Close < 2 in.
0-25 Very Poor Thin Close 2 in.-12 in.
25-50 Poor Medium Moderately Close 12 in.-36 in. II
50-75 Fair Thick Wide 36 in.-10 ft
75-90 Good Massive Very Wide > 10 ft
90-100 Excellent
GRO i
I
I
a Table 3A
SUMMARY OF LABORATORY RESULTS
1 Sample Information Atterberg Limits
Moisture Dry Unit Liquid Plasticity Fines
I Location Sample Depth,ft Elevation,ft Content, % Weight, pcf Limit, % Index,% Content,% Soil Type
B-1 S-1 1.0 25 Silty CLAY
S-2 2.5 - 29 - - - - Silty CLAY
S-3 5.0 - 26 - _ Silty CLAY
B-2 S-1 1.0 25 Silty CLAY
S-2 2.5 - 23 - - - 86 Silty CLAY
I S-3 5.0 - 26 - Silty CLAY
B-3 S-1 2.5 26 88 Silty CLAY
S-2 5.0 - 28 - _ _ - Silty CLAY
S-3 7.5 29 94 Silty CLAY
S-3 8.3 - 27 - - - 45 Silty SAND
V S-4 10.0 - 44 - _ _ - Silty SAND
B-4 S-1 3.0 21 92 Silty CLAY
S-1 3.5 - 19 101 - - - Silty CLAY
S-2 4.5 - 25 - _ - Silty CLAY
S-3 7.5 39 39 Silty SAND
S-4 10.0 - 37 - - - - Silty SAND
S-5 12.5 - 26 - - - - Silty SAND
B-5 S-1 1.0 - 27 - - - - Silty CLAY
S-2 2.5 - 20 - 52 29 - Silty CLAY
it 5-3 5.0 - 18 - - - Silty CLAY
B-6 S-2 5.0 30 46 18 Silty CLAY
S-3 7.5 - 37 - - - 40 Silty SAND
IS-4 10.0 - 33 - - - - BASALT
B-7 S-1 1.0 - 26 - - - - Silty CLAY
• S-2 2.5 - 26 - - _ - Silty CLAY
S-3 5.0 25 Silty CLAY
B-8 S-1 1.0 - 24 - - - - Silty CLAY
S-2 2.5 - 22 - _ _ - Silty CLAY
S-3 5.0 26 Silty CLAY
B-9 S-1 2.5 - 28 - - - - Silty CLAY
S-2 5.0 - 27 - - Silty CLAY
S-3 7.5 40 Silty CLAY
B-10 S-1 3.0 - 25 89 - - - Silty CLAY
> S-1 4.2 - 22 - - - 93 Silty CLAY
S-2 4.5 28Silty CLAY
S-4 10.0 - 54 - - - 65 BASALT
I B-11 S 1 1.0 - 27 - Silty CLAY
5 2 2.5 20 Silty CLAY
S-3 5.0 - 29 - - - - Silty CLAY
I
IG R u Page 1 of 1
BORING AND TEST PIT LOG LEGEND 1
SOIL SYMBOLS SAMPLER SYMBOLS I
Symbol Typical Description Symbol Sampler Description
LANDSCAPE MATERIALS I 2.0-in. O.D. split-spoon sampler and Standard
%:•:++ Penetration Test with recovery (ASTM D1586)
FILL I Shelby tube sampler with recovery
(ASTM D1587)
3.0-in. O.D. split-spoon sampler with recovery
,pa GRAVEL;clean to some silt, clay, and sand (ASTM D3550)
,.Q Sandy GRAVEL; clean to some silt and clay Vic Grab Sample
t, Silty GRAVEL; up to some clay and sand Rock core sample interval 111
17�� Clayey GRAVEL; up to some silt and sand I Sonic core sample interval I
''i:': SAND;clean to some silt, clay, and gravel Geoprobe sample interval
4�,f
<{; Gravelly SAND;clean to some silt and clay INSTALLATION SYMBOLS
:},
�• Silty SAND; up to some clay and gravel Symbol Symbol Description
Clayey SAND; up to some silt and gravel ® Flush-mount monument set in concrete I
SILT; up to some clay, sand, and gravel ti Concrete,well casing shown where applicable
GravellySILT; upto some clayand sand j'j applicable
well casing shown where
�!�! / /
1:1j•1 Sandy SILT; up to some clay and gravel ff Filter pack, machine-slotted well casing shown
'• where applicable
DIClayey SILT; up to some sand and gravel Grout, vibrating-wire transducer cable shown J
/ where applicable
/. CLAY; up to some silt, sand, and gravel 0 Vibrating-wire pressure transducer
r Gravelly CLAY; up to some silt and sand I 1-in.-diameter solid PVCI
I
Sandy CLAY; up to some silt and gravel 1-in.-diameter hand-slotted PVC
1111 Silty CLAY; up to some sand and gravel Grout, inclinometer casing shown where I
applicable
PEAT
FIELD MEASUREMENTS
I
BEDROCK SYMBOLS Symbol Typical Description
Symbol Typical Description a Groundwater level during drilling and date
measured
+++ BASALT i Groundwater level after drilling and date
o +++ measured
-�w MUDSTONE Rock core recovery (%)
w _--1SILTSTONE Rock quality designation (RQD, %)
H
SANDSTONE
ET11
W SURFACE MATERIAL SYMBOLS
w Symbol Typical Description
U'
o .
Asphalt concrete PAVEMENT
P . Portland cement concrete PAVEMENT
I
a ov t
z °p° Crushed rock BASE COURSE
a
0
03
I
co CLASSIFICATION OF MATERIAL o a z • BLOWS PER FOOT %
1 (—i g 2 o ❑• FINS CONTENT,OISTURE
%111
_ _ = a a a U LIQUID LIMIT,% COMMENTS AND
a a m 0
~r PLASTIC LIMIT,% ADDITIONAL TESTS
o o Surface Elevation: Not Available o � co u) on 0 50 100
// Silty CLAY to clayey SILT,trace fine-grained sand,
J,/ brown,medium stiff,contains organics,4-in:thick 2 7
I
/ heavily rooted zone atground surface(Residual S-1 a f
J/ Soil) 5 '; t
: --stiff at 2.5 ft s2 5
J 7
I
8 --very stiff below 5 ft a _1si
S3 I 6
6.5 10
— (12/14/2018)
Groundwater not encountered
10—
15—
ii, —
111 20—
It — .
25
m
n
v —
I-
0
1111 —
C7
5
a
w 30—
1 ~
a
0
ie
w
-
J
35—
N
n_
O
O
O
O
Z
0
0ea _
1 c9—40 0 0.5 1.0
Logged By: M.Rauthause Drilled by: Western States Soil Conservation,Inc. • TORVANE SHEAR STRENGTH,TSF
■ UNDRAINED SHEAR STRENGTH,TSF
Date Started: 12/14118 GPS Coordinates: Not Available
I.
Drilling Method: Hollow-Stem Auger Hammer Type:Auto Hammer ///���++
Equipment: CME 850 Track-Mounted Drill Rig Weight:140 lb ( T T BORING B-1
Hole Diameter: 8 in. Drop:30 in. V 1
Note:See Legend for Explanation of Symbols Energy Ratio:
APR.2019 JOB NO.5970-K FIG.1A
I
o CLASSIFICATION OF MATERIAL o A BLOWS PER FOOT
1- o 1- O a j • MOISTURE CONTENT,
1-1- v " W W O ❑ FINES CONTENT,%
F a = ¢ _1 a —F LIQUID LIMIT,% COMMENTS AND
w w z Q Q o PLASTIC LIMIT,% ADDITIONAL TESTS
o co Surface Elevation: Not Available o ( w m 0 50 100
j Silty CLAY to clayey SILT,trace fine-grained sand,
brown,medium stiff,contains organics,4-in.-thick
i 2 5
heavily rooted zone at ground surface(Residual S1 z41\ Ill
t 3 _iG f
I
i)ff below 2.5 ft S-2 s 4 / Q
:///
I
8
Iii
5 4
s-3 I 5 1^• E.
(12/14/2018) 6.5 7 .
Groundwater not encountered
lr
10-
15- I
I
20- 1
I
25-
y
a -
0
L
I
g -
a
w 30-
1-
F - Ia
0
> —
w
J
W -
ZI
a
35-
a
U' —
0
0I
—
O
z
0
0
m
0-40 1
0 0.5 1.0
Logged By: M.Rauthause Drilled by: Western States Soil Conservation,Inc. • TORVANE SHEAR STRENGTH,TSF
Date Started: 12/14/18 GPS Coordinates: Not Available II UNDRAINED SHEAR STRENGTH,TSF
Drilling Method: Hollow-Stern Auger Hammer Type:Auto Hammerit
Equipment: CME 850 Track-Mounted Drill Rig Weight:140 lb BORING B-2
Hole Diameter: 8 in, Drop:30 in. G R I I
Note:See Legend for Explanation of Symbols Energy Ratio:
APR.2019 JOB NO.5970-K FIG.2A
I
♦ BLOWS PER FOOT
p CLASSIFICATION OF MATERIAL o o a z • MOISTURE CONTENT,
I -, W o ❑ FINES CONTENT,% COMMENTS AND
_ _ = a a a v LIQUID LIMIT,%
w < w a a o ~�PLASTIC LIMIT,% ADDITIONAL TESTS
0 'r Surface Elevation: Not Available o z o m C0 0 50 100
1 // Silty CLAY to clayey SILT,trace fine-grained sand,
brown,stiff,contains organics,4-in.-thick heavily
rooted zone at ground surface(Residual Soil)
s _1a
11 S-1 I 8 4 ♦ 1 Loss of drilling fluid
6 circulation between
depths of 2.5 to 7.5 ft.
i Drilling mud observed
5 T 6 12 1 seeping out of the
s2 I 5 slope approximately
I
7 l 10 ft do from
I exploration
T4 33 ❑
I `• 5ilty SAND,green-gray with rust staining and white 8.3 S3 L 24 ir
, mineralization,dense,relict rock structure,fine to io- :: '. : coarse grained,contains gravel-sized fragments of s
4:;::; predominantly decomposed basalt(Decomposed S-4 1 18 ..,
I ;.;,r Basalt) 30
—,:.;•'
12.5 40 40-50-50/5"_
—+. + BASALT,gray,brown,and green-gray with rust
+++ staining,predominantly decomposed to 139 s5 53/5"
decomposed,extremely soft to very soft(RO to R1) r
I' 15— 1(Columbia River Basalt)
/
_ (12/13/2018)
—
ft
20—
I
25
I
e —
— 1=
II ui
a.
w 30-
F
I 0
ec—
> —
J
z
in
35—
a
O —
IQ
—_
O
O
z
0
O
11, ° 40
0 0.5 1.0
Logged By: M.Rauthause Drilled by: Western States Soil Conservation,Inc. • TORVANE SHEAR STRENGTH,TSF
Date Started: 12/13/18 GPS Coordinates: Not Available ■ UNDRAINED SHEAR STRENGTH,TSF
IIIDrilling Method: Mud Rotary Hammer Type:Auto Hammer
Equipment: CME 850 Track-Mounted Drill Rig Weight:140 lb R'I BORING B-3
Hole Diameter: 4 in. Drop:30 in.
Note:See Legend for Explanation of Symbols Energy Ratio:
APR.2019 JOB NO.5970-K FIG.3A
I
BLOWS PER FOOT
CLASSIFICATION OF MATERIAL o a 1- • MOISTURE CONTENT,%
g ? O 0 FINES CONTENT,
I- a 1- F a s �E LIQUID LIMIT,% COMMENTS AND
w O.
— ¢ ¢ of PLASTIC LIMIT,% ADDITIONAL TESTS
o co Surface Elevation: Not Available o Z co co m 0 50 100
// Silty CLAY to clayey SILT,trace fine-grained sand, j
�J/ brown,stiff,contains organics,4-in.-thick heavily
// rooted zone at ground surface(Residual Soil)
S-1 :• .fi0
:7/ --very stiff below 4.5 ft 7 17 S Dry Density=101 pcf
5 1 S-2 7 \ \
I
—f t::: Silty SAND,gray with rust staining,medium dense, 7.5 7 28
•
T;' relict rock structure,fine to coarse grained S-3 116
r'ssy (Decomposed Basalt)
Z.10—`.'-"'.. --contains gravel-sized fragments of predominantly 17 I \.
_ To decomposed basalt,very dense below 9.5 ft S4I 27 �;
`. 27 \ .
': ° : --white and green mineralization below 12.5 ft 26 �' 74�
S-5 36
15 ++ L 15.0 r 32 32-50/4.5"-
+ + BASALT,gray with rust staining and green to white sfi 1_5014.5'
mineralization,predominantly decomposed to 15.9
decomposed,extremely soft to very soft(RU to R1)
(Columbia River Basalt) '
— (12/13/2018) I
20ill
25—
H
Iii
a
w 30—
H
0 _
17 0
0
w
. 35—
w
a
z
0 _
°—aa
0 0.5 1.0II
Logged By: M.Rauthause Drilled by: Western States Soil Conservation,Inc, • TORVANE SHEAR STRENGTH,TSF
Date Started: 12/13/18 GPS Coordinates: Not Available • UNDRAINED SHEAR STRENGTH,TSF
Drilling Method: Mud Rotary Hammer Type:Auto Hammer
Equipment: CME 850 Track-Mounted Drill Rig Weight:140 lb GE BORING B-4
Hole Diameter: 4 in. Drop:30 in.
Note:See Legend(or Explanation of Symbols Energy Ratio:
APR.2019 JOB NO.5970-K FIG.4A
I
o CLASSIFICATION OF MATERIAL o a z •
BLOWS PER FOOT
o • MOISTURE CONTENT,%
c> LU 3 z < o 0 FINES CONTENT,%
x = J J f.�LIQUID LIMIT,% COMMENTS AND
x
W w 0 PLASTIC LIMIT,% ADDITIONAL TESTS
o co Surface Elevation: Not Available o z co co co 0 50 100
j Silty CLAY to clayey SILiT,
ff trace fine-grained sand,
brown,soft to medium st ,contains organics, t 4
4-in.-thick heavily rooted zone at ground surface s-i 1 A
(ResidualSoil) 3
--medium stiff to stiff at 2.5 ft sz 4 -s\ ,aq
4
5 / --very stiff below 5 ft 4 161i i
i
S-3 7
- (12/14/2018) ss s
Groundwater not encountered
10-
I 15-
i _
20 .
I
I 25
e
H
I � -
5
a
w 30-
a
0
ET
0
> -
z . .
. 35-
F
a
IQ
O
O
z
0
O _
II (0
Ft
c7-40 0 0.5 1.0
•
Logged By: M.Rauthause Drilled by: Western States Soil Conservation,Inc. TORVANE SHEAR STRENGTH,TSF
Date Started: 12/14/18 GPS Coordinates: Not Available ■ UNDRAINED SHEAR STRENGTH,TSF
Drilling Method: Hollow-Stem Auger Hammer Type:Auto Hammer 7�
Equipment: CME 850 Track-Mounted Drill Rig Weight:140 in. { [ I BORING B-5
Hole Diameter. 8 in. Drop:30 in. j
Note:See Legend for Explanation of Symbols Energy Ratio:
APR.2019 JOB NO.5970-K FIG 5A
r
BLOWS PER FOOT
o CLASSIFICATION OF MATERIAL o o ;i z • MOISTURE CONTENT,
a v a g Z o ❑ FINES CONTENT,
_ = a a a U LIQUID LIMIT,% COMMENTS AND
I- a a Ill I- m m o ~�PLASTIC LIMIT,% ADDITIONAL TESTS
0 CO Surface Elevation: Not Available o z a) m 0 50 100
Silty CLAY to clayey SILT,trace fine-grained sand, I I
brown mottled gray,stiff,contains organics,
4-in.-thick heavily rooted zone at ground surface . .
(Residual Soil)
s1 1
5 I 5 i2 I
sz s ��-1
s
t
—'i'^TSilty SAND,gray with rust staining and white 7 5 $3 r 13 t43
`.`?. mineralization,dense,relict rock structure,fine to 1
. .1: coarse grained,contains gravel-sized fragments of �-,,,,
10 ` _ ..-1predominantlydecomposedbasalt(Decomposed f io.o r 25 f 25-16-50/5'
+++ ,Basalt) / s-a 1 16 . t
+++ BASALT,gray with rust staining and white 1 so 5 , . I
—+++ mineralization,predominantly decomposed to —
+++ (Columbia
extremely Basalt)
soft to very soft(RO to Ri) II
/1/,
+++ (Columbia River Basalt)
—+++ --some vesicles,moderately weathered to
15 +++ predominantly decomposed,very soft to medium Run 1
hard(R1 to R3),open joints with clay infilling below
+++ 12 ft
+++ ///
+++ ,�/
+++ Run 2 �� I
20—+++
+▪++ f
+++ 22.5 -
- (12/14/2018)
25—
m —
E
e —
F
a
(7 —
O
w 30—
F.
1
o _ +
Fe —
0
> —
w
—
o
z
. 35—
w
a_
0 -
(5
z —
0
0 _
CO
EL
c'—40 0 0.5 1.0
•
Logged By: M.Rauthause Drilled by: Western States Soil Conservation,Inc. TORVANE SHEAR STRENGTH,TSF
Date Started: 12/14/18 GPS Coordinates: Not Available ■ UNDRAINED SHEAR STRENGTH,TSF
Drilling Method: Mud Rotary Hammer Type:Auto Hammer /� 7�
Equipment: CME 850 Track-Mounted Drill Rig Weight:140 lb T L/ T BORING B-6
Hole Diameter. 4 in. Drop:30 in. v j` j
Note:See Legend for Explanation of Symbols Energy Ratio:
APR.2019 JOB NO.5970-K FIG.6A
I
BLOWS PER FOOT
1— o CLASSIFICATION OF MATERIAL - d a I— ■ MOISTURE CONTENT,%
0g w o 0 FINES CONTENT,%
I a - -' hi--LIQUID LIMIT,% COMMENTS AND
w — w z ¢ cd of PLASTIC LIMIT,% ADDITIONAL TESTS
CL
0 c� Surface Elevation: Not Available o z `" "' m 0 50 100
I // Silty CLAY to clayey SILT,trace fine-to
medium-grained sand,brown,very soft to soft, 0 2
contains organics,4-in.thick heavily rooted zone at s-1 1
ground surface(Residual Soil) 1 i
--medium stiff at2.5ft 1 5
sz 1
/,)
5
I
--stiff to verystiff below 5 ft 5
5 53 6
— (12/14/2018) 65 s
IGroundwater not encountered
10—
i 15—
I
II 20i zz
25—
e —
1-
0
rw -
a
w 30— '
✓
F ,
O
> —
w .
J ? 35—
m I
a
U'
IC
2
a
O
co
1 6-4 0
0 OS 1.0
Logged By: M.Rauthause Drilled by: Western States Soil Conservation,Inc • TORVANE SHEAR STRENGTH,TSF
Date Started: 12/14/18 GPS Coordinates: Not Available ■ UNDRAINED SHEAR STRENGTH,TSF
Drilling Method: Hollow-Stem Auger Hammer Type:Auto Hammer
Equipment:met CME 850 Track-Mounted Drill Rig Weight:rop 140 in. ' T I BORING B-7
Hole Diameter: 8 in. Drop:30 in. V
Note:See Legend for Explanation of Symbols Energy Ratio:
ii
APR.2019 JOB NO.5970-K FIG.7A
I
p CLASSIFICATION OF MATERIAL o a- z ♦ BLOWS PER FOOT
• MOISTURE CONTENT,%
tL 3tr ? o 0 FINES CONTENT,%
J -' -' `___r-LIQUID LIMIT,% COMMENTS AND
a ae
a w m a Q o PLASTIC LIMIT,% ADDITIONAL TESTS
o 0 Surface Elevation: Not Available w < m 0 50 1c0
Silty CLAY to clayey SILT,trace fine-grained sand, I
brown,stiff to very stiff,contains organics, 2 to
4-in.-thick heavily rooted zone at ground surface 5-1 3
/ (Residual Soil) 5 I
J S-2 8 1
10
1
5 / &3I 7 t5 , _
6.5 8 Sample S-3 includes
(12/14/2018) decomposed basalt at
tip of sampler
Groundwater not encountered
10-
I
15 '
I
20- 1
I
25-
aI
z.
-
I-
o
csIT
-
a
w 30-
I
0 -
0
in
0I. 35-
Fi
U, - .
0
0 -
O .
Z .
0
0
co
E
C9—40 1
0 I 0.5 1.0
•
Logged By: M.Rauthause Drilled by: Western States Soil Conservation,Inc. TORVANE SHEAR STRENGTH,TSF
Date Started: 12/14/18 GPS Coordinates: Not Available MI UNDRAINED SHEAR STRENGTH,TSF
Drilling Method: Hollow-Stem Auger Hammer Type:Auto HammerI
Equipment:met CME 850 Track-Mounted Drill Rig Weight:Drop 140 in. BORING B-8
Hole Diameter: 8 in. Drop:30 in. G RI Note:See Legend for Explanation of Symbols Energy Ratio:
APR.2019 JOB NO.5970-K FIG.8A
I
BLOWS PER FOOT
CLASSIFICATION OF MATERIAL o o a z MOISTURE CONTENT,%
A
Jj g w O 0 FINES CONTENT,%
a a P-F LIQUID LIMIT,% COMMENTS AND
w Z ¢ co 0 PLASTIC LIMIT,% ADDITIONAL TESTS
0 o Surface Elevation; Not Available a- z co co co o 50 oe
I J Silty CLAY to clayey SILT,trace fine-grained sand,
brown mottled gray,stiff,contains organics,
4-in.-thick heavily rooted zone at ground surface
I (Residual Soil) r 3 _ts
at 1 7 4 if
i 6
I
5 4 11 ii
/ S2 I 5
8 \ \
II i
I 3
3 20
+++ BASALT,gray with rust staining and white 1
+++ mineralization,predominantly decomposed to 8.5
10+++ decomposed,extremely soft to very soft(RO to R1) s4 T 23 �zs 5015•:
I +++ \(Columbia River Basalt) r 10.9 L sors
(121132018)
I 15-
1
I 20—
I
I25-
- .
I .
b
r -
a
w 30—
r
I ~
a
F
0
w
z
0
F
35—
a
o 0 —re
0
0an —
I °-40
0 0.5 1.0
Logged By: M.Rauthause Drilled by: Western States Soil Conservation,Inc. • TORVANE SHEAR STRENGTH,TSF
Date Started: 12/13/18 GPS Coordinates: Not Available • UNDRAINED SHEAR STRENGTH,TSF
Drilling Method: Mud Rotary Hammer Type:Auto Hammer /� I
Equipment: CME 850 Track-Mounted Drill Rig Weight:140 lb ( I R BORING B-9
Hole Diameter. 4 in. Drop:30 in. �J 1 \
Note:See Legend for Explanation of Symbols Energy Ratio:
APR.2019 JOB NO.5970-K FIG.9A
I
BLOWS PER FOOT
o CLASSIFICATION OF MATERIAL o a ~
o d z • MOISTURE CONTENT,%
v g w in O ❑ FINES CONTENT,
_ J 52 1-1—LIQUID LIMIT,% COMMENTS AND
w w ¢ a o PLASTIC LIMIT,% ADDITIONAL TESTS
0 o Surface Elevation: Not Available o co co co 0 so 100
iSilty CLAY to clayey SILT,trace fine-grained sand,
brown,very stiff,contains organics,4-in:thick
heavily rooted zone at ground surface(Residual
Soil) 0.50
• Dry Density=89 pd
S1
L
6 _18
5� S2 7
\ ,
11
II
-,+++ BASALT,brown with rust staining,predominantly 7.5 10 r3 .
+++ decomposed to decomposed,extremely soft to very S3 I 15+++ soft(RD to R1)(Columbia River Basalt)10�+++ —extremely soft to very soft(RD to R2)below 10 ft17t4
�+++ S-4 I 7 W
+++ L 7
+▪++ 15 N48
—
+++ S-5 I 17
3 / , .
+++ 1
15 ▪++
+++ 18 35�
�+++ S8 I 17
+++ 18
+++
+++
+++ ti
,+++ N
�+++ NN:
20--+++ --gray with green mineralization below 20 ft
38 38-32-50/5'.
+++
J32 ..* il
+++ 21 4 &8 50 5'
(12/13/2018)
I
25- -
m
v
0
0
w
5I
a
w 30—
4
F.
a
d
0
> —
w
0
z
35— I
N
a
U' —
0
—O
J
11,
Z —
r
0
—
co
a I .
"—40
0 0.5 1.0
Logged By: M.Rauthause Drilled by: Western States Soil Conservation,Inc. • TORVANE SHEAR STRENGTH,TSF
■ UNDRAINED SHEAR STRENGTH,TSF
Date Started: 12113l18 GPS Coordinates: Not Available
Drilling Method: Mud Rotary Hammer Type:Auto HammerI
Equipment: CME 850 Track-Mounted Drill Rig Weight:140 lb BORING B-10
Hole Diameter: 4 in. Drop:30 in. G 1 \ l
Note:See Legend for Explanation of Symbols Energy Ratio:
APR.2019 JOB NO.5970-K FIG.10A
I
p CLASSIFICATION OF MATERIAL o A BLOWS PER FOOT
o a z • MOISTURE CONTENT,
II
_,
iL 0 -, z O ID FINES CONTENT,
1- Cl- F a a s J_4 LIQUID LIMIT,% COMMENTS AND
w < w a ¢ of PLASTIC LIMIT,% ADDITIONAL TESTS
o co Surface Elevation: Not Available o
_
co co m 0 50 100
I // Silty CLAY to clayey SILT,trace fine-grained sand, { ' 1
brown,very soft to soft,contains organics, o ,
J
4-in:thick heavily rooted zone at ground surface s1 o r �i
(Residual Soil) n 13 iiii.
---stiff below 2.5 R sz s
5 /
J J' s-3 I 4 1: •
(12/14/2018) ss
1 Groundwater not encountered
10—
I
3 15—
1 — 1
I20—
25- .
o —
F
II 2
H
a
w 30—
0
' _ I
0
a 1
ILLI
_
0
. 35—
a
rc,. :_ ,
z
rc
o _
Im
rc
0-40
0 0.5 1.0
•
Logged By: M.Rauthause Drilled by: Western States Soil Conservation,Inc. TORVANE SHEAR STRENGTH,TSF
IDate Started: 12/14/18 GPS Coordinates: Not Available • UNDRAINED SHEAR STRENGTH,TSF
Drilling Method: Hollow-Stem Auger Hammer Type:Auto Hammer
Equipment:Imet CME 850 Track-Mounted Drill Rig Weight:Drop 140 in. G I R T BORING B-11
Hole Diameter. 8 in. Drop:30 in. j \ 1
Note:See Legend for Explanation of Symbols Energy Ratio:
APR.2019 JOB NO.5970-K FIG.11A
I
BLOWS PER FOOT
0 CLASSIFICATION OF MATERIAL o o a z ■ MOISTURE CONTENT,
I—- o LL 3 w o ❑ FINES CONTENT,%
a 1- F a a 3 ��LIQUID LIMIT,% COMMENTS AND
ow w - ¢ ¢ of PLASTIC LIMIT,% ADDITIONAL TESTS
o o Surface Elevation: Not Available O z 0 m 0° 0 50 100
Silty CLAY to clayey SILT,trace fine-grained sand, I
brown,stiff,contains organics,4-in.-thick heavily
rooted zone at ground surface(Residual Soil) ,
2 _10 I
S1 4 A
6
..
5 3 11
S2 I 5 A .
61
3 12
S3 I 5
1
I
10 ' a 15
7
. Silty SAND,gray with pink,white,and red 11.0 � I 3
mineralization,medium dense,relict rock structure,
=+-1 fine grained(Decomposed Basalt) % 12.5 111 166
+++ •• 5-5 10
BASALT,gray with rust staining and pink to white 6
+++ mineralization,predominantly decomposed to
15—+++ decomposed,extremely soft to soft(RO to R2), 7 17
+++ open joints with clay infilling(Columbia River s6 10
+++ Basalt) 7
+++ I
+++
-,+++
+++
+++
-+++
+++
20+++ 1D 33I
+++ S-7 I 17
,+++
+++ 16
+++
+++ _ I
+++
�+++ 1- 3D _L.______ 305/4"-
S-8 I_ ----- ---
25—+++ --some vesicles,moderately weathered to slightly _ s/a /// ",
+++ weathered,soft to hard(R2 to R4),closed fractures
+++ below 25 ft
a -+++ c —
1- +++
5 +++ 29.0
(41412019)
-
m 30—
0
F — •
0I
0 •
> I
' 35-
0
a
0 —
U at
0 — _
z —
¢ i
0
-40 II
0 0.5 1.0
Logged By: G.Martin Drilled by: Western States Soil Conservation,Inc • TORVANE SHEAR STRENGTH,TSF
Date Started: 4/4/19 GPS Coordinates: 45.4074°N -122.8456°W(WGS 84) • UNDRAINED SHEAR STRENGTH,TSF
Drilling Method: Mud Rotary Hammer Type:Auto HammerI/
Equipment: CME 55 HT Track-Mounted Drill Rig Weight:140 lb V T RIT BORING B-12
Hole Diameter. 5 in. Drop:30 in. I
Note:See Legend for Explanation of Symbols Energy Ratio:0.76 1
APR.2019 JOB NO.5970-K FIG.12A
I
A BLOWS PER FOOT
o CLASSIFICATION OF MATERIAL o d a j • MOISTURE CONTENT,
0 ri g w W 0 ❑ FINES CONTENT,%
a = a a a j�LIQUID LIMIT,% COMMENTS AND
w < w ¢ ¢ OJ PLASTIC LIMIT,% ADDITIONAL TESTS
o co Surface Elevation: Not Available o Z V' co') f° 0 50 100
1 ' Silty CLAY to clayey SILT,trace fine-grained sand,
brown,medium stiff to stiff,contains organics,
4-in.-thick heavily rooted zone at ground surface
(Residual Soil) 2 8
,1 S1 � 4
/ 4
5 / --very stiff at 5 ft
7 21
/ sz 1 8
13
7.5 r
1 — ..?`. i Silty SAND,gray with pink,white,and red $3 1 22 4
r; mineralization,medium dense,relict rock structure, 18
A\.
J'.. it
fine grained(Decomposed Basalt)
10--c*:: --very dense at 10 ft
18 61
ai
:..•... S4 34
34
—: 'r; N.
BASALT,gray with rust staining and pink to white 12.5 S r s 1 zs zazaso s.s:
+++ mineralization,predominantly decomposed to 50/5.5"
+++ decomposed,extremely soft to soft(RO to R2),
15^+++ open joints with clay infilling(Columbia River 35 35-35-50/5"
—a+++ Basalt) S6 35
+++ 50/5'
i +++
+++
+++ I 24 _ I
+++ S-7 41
+^ ++ 49
+++
20—,*++
+++
+++
�+++
+++ 24 47
',+++ S-8 I 21
�+++ 26
+++
25 ++
I �+++ --some vesicles,moderately weathered to slightly 26 2a5o 5o/a
Fr: +++ weathered,soft to hard(R2 to R4),closed fractures s s s0 •
A
a -*++ below 26 ft 50/4"
F +++
11
/�+++Ja +++
30 "1 w +++o /I �
+++
��� 32.0
0 (4/4/2019)
> —
I w
. 35— 1
a
O -
O
z -
K .
0 _
Im
—40
0 0.5 1.0
Logged By: G.Martin Drilled by: Western States Soil Conservation,Inc. • TORVANE SHEAR STRENGTH,TSF
Date Started: 4/4/19 GPS Coordinates: 45.4075°N -122.8447°W(WGS 84) ■ UNDRAINED SHEAR STRENGTH,TSF
Drilling Method: Mud Rotary Hammer Type:Auto Hammer /� 7�
Equipment: CME 55 HT Track-Mounted Drill Rig Weight:140 lb il BORING B-13
Hole Diameter: 5 in. Drop:30 in. j \
Note:See Legend for Explanation of Symbols Energy Ratio:0.76
APR.2019 JOB NO.5970-K FIG.13A
I
o CLASSIFICATION OF MATERIAL a • MOISTURE CONTENT,
1- 0 LL z ' ❑ FINES CONTENT, I
"' f or.LIQUID LIMIT,% COMMENTS AND
PLASTIC LIMIT,% ADDITIONAL TESTS
= S = J J
W Cr W < <
Q Q
D (.0(' Surface Elevation: Not Available co 0 50 too
Silty CLAY to clayey SILT,trace fine-grained sand,brown,
/ soft to medium stiff,contains organics,4-in.-thick heavily
rooted zone at ground surface(Residual Soil)
I
J ,
5—/ 1
` 1
10 +++ BASALT,gray and black,predominantly decomposed to 10.0
_++++ decomposed,extremely soft to soft(RO to R2)(Columbia IIIIIIIIIIIIIIIIIIII
River Basalt) ,- 11.5it
— (4/3/2019)
— Groundwater not encountered I
15—
I
I
20—
J
AI
F
a
1
a 25—
w
I- -
❑ -
t7I
a
> —
w
w
z —
0.
30 0 0.5 1.0
o° • TORVANE SHEAR STRENGTH,TSF
EL
Logged By: M.Rauthause Excavated by: BenchmarkContracting Equipment: CAT 326E ExcavatorI 0 Date Started: 4/3119 GPS Coordinates: Not Available I Note: See Legend for Explanation of Symbols
G R I TEST PIT TP-13 III
APR.2019 JOB NO.5970-K FIG.14A I
I
p CLASSIFICATION OF MATERIAL a • MOISTURE CONTENT,%
I- z i- 0 FINES CONTENT,%
= 0- '--� LIQUID LIMIT,% COMMENTS AND
Eh' a a m PLASTIC LIMIT,
w w 'Li
ADDITIONAL TESTS
I o ° Surface Elevation: Not Available 0 50 100
Silty CLAY to clayey SILT,trace fine-grained sand,brown,
soft to medium stiff,contains organics,4-in:thick heavily
rooted zone at ground surface(Residual Soil)
0.30
I 5—
'`;: Silty SAND,gray with rust staining,fine to coarse grained, 6.5 110101111111
contains gravel-to boulder-sized fragments of
v.
predominantly decomposed basalt(Decomposed Basalt)
II ',F.4:
10—
is
I
13.0
_++1±±_\Basalt) sedyvery softt sporft(R11to R2)(Columbia River 1a5 "Ill""'�1"
15— (4/3/2019)
1111111111111111111
I Groundwater not encountered
i
20-
—
4-
1-
0
ci —
I ~
a 25—
w
w
r —
1-
ig o
U
- > -
w
J
w A
Iz
u
30 0 0.5 1.0
o
• TORVANESHEARSTRENGTH,TSF
r
Logged By: M.Rauthause Excavated by: Benchmark Contracting Equipment: CAT 326F Excavator
0 Date Started: 4/3/19 GPS Coordinates: Not Available I Note: See Legend for Explanation of Symbols
I G R0 TEST PIT TP-14
IAPR.2019 JOB NO.5970-K FIG.15A
I
CD CLASSIFICATION OF MATERIAL wa • MOISTURE CONTENT,%
1- _ LL z ❑ FINES CONTENT,%
_ _ _ �(—LIQUID LIMIT,% COMMENTS AND
W w m PLASTIC LIMIT,% ADDITIONAL TESTS
Surface Elevation: Not Available C4 0 50 10o
Silty CLAY to clayey SILT,trace fine-grained sand,brown,
_ soft to medium stiff,contains organics,scattered
subrounded gravel and boulders,4-in.-thick heavily rooted
— zone at ground surface(Residual Soil)
.0.25
5— I
Silty SAND,gray with rust staining and white 6.5
mineralization,fine to coarse grained,contains gravel-to
—..'` ;- boulder-sized fragments of predominantly decomposed
1 basalt(Decomposed Basalt)
. zt
10-';�X . I
+++ BASALT,gray and black,predominantly decomposed to - 11.0
+++ decomposed,very soft to soft(R1 to R2)(Columbia River
+++ Basalt)
+++
+++
—+++ --moderately weathered to decomposed below 14 ft
I/
15 +++
—++++ --includes fragments of soft to medium hard(R2 to R3)
+++ basalt at 16 ft
_+++ . .
+++
+++
+++ --includes fragments of medium hard(R3)basalt at 18 ft
(4/32019) 1s.5
20_ Groundwater not encountered
I-
0
t9 —
ui a 25—
s C
w
r — .
a
Ec
0
Ec
J
W
Io
EL 30 0 0.5 1.0
o • TORVANE SHEAR STRENGTH,TSF
H Logged By: M.Rauthause Excavated by: Benchmark Contracting Equipment: CAT 326F Excavator
0 Date Started: 4/3/19 GPS Coordinates: Not Available Note: See Legend for Explanation of Symbols
G R'1 TEST PIT TP-15 I
APR.2019 JOB NO.5970-K FIG.16A i
1 ,
co CLASSIFICATION OF MATERIAL a • MOISTURE CONTENT,%
L z •
0 FINES CONTENT,%
"' LI, h_ LIQUID LIMIT,% COMMENTS AND
a CL
m -PLASTIC LIMIT,% ADDITIONAL TESTS
I Surface Elevation: Not Available 0 50 100
Silty CLAY to clayey SILT,trace fine-grained sand,brown,
_/ medium stiff,contains organics,4-in:thick heavily rooted
zone at ground surface(Residual Soil)
1
♦0.40
I 5—/
I
11
10—/
I
15 •I ; k; Silty SAND gray with rust and white 15.0
:::,..; n 9 Y 9
mineralization,fine to coarse grained,contains gravel-to
;. boulder-sized fragments of predominantly decomposed
e basalt(Decomposed Basalt) J 17.0
I '" BASALT,gray and black,predominantly decomposed to 17.5
— \decomposed,extremely soft to soft(RO to R2)(Columbia
River Basalt)
(4/3/2019)
I 20=
Groundwater not encountered
I
F25—
W
F —
I-
I ❑ _
K
W
J
W I
U(5
O
Z
30 0 0.5 1.0
c9
°o • TORVANE SHEAR STRENGTH,TSF
- Logged By: M.Rauthause Excavated by: Benchmark Contracting Equipment: CAT 326F Excavator
0 Date Started: 4/3/19 GPS Coordinates: Not Available Note: See Legend for Explanation of Symbols
G'R -
Q TEST PIT TP 16
IAPR.2019 JOB NO.5970-K FIG.17A
I
CLASSIFICATION OF MATERIAL a • MOISTURE CONTENT,
1 I— z ❑ FINES CONTENT, I= x = LU W �-LIQUID LIMIT,% COMMENTS AND
. a 1— a a PLASTIC LIMIT,% ADDITIONAL TESTS
Surface Elevation: Not Available o CO 0 50 100
f// Silty CLAY to clayey SILT,trace fine-grained sand,brown, 1
_/ medium stiff,contains organics,4-in:thick heavily rooted
_/ zone at ground surface(Residual Soil)
I
J .0.30
5—/
10-/
I
1
J/
; � - 13.5
_.:•-., ,. Silty SAND,gray with rust staining and white I
mineralization,fine to coarse grained,contains gravel-to
15-•- boulder-sized fragments of predominantly decomposed I. 15.o
• • ,basaltiDecomposed Basalt) J 15.5
- BASALT,gray and black,predominantly decomposed to
decomposed,very soft to soft(R1 to R2)(Columbia River
- Basalt)
_ (4/3/2019)
— Groundwater not encountered
20= 1
I
O• —
0 25—
I w
ti —
a
1-
w
I
J
W
2 1 a 30 0 0 0.5 1.0
o • TORVANE SHEAR STRENGTH,TSF
o
a
Logged By: M.Rauthause Excavated by: Benchmark Contracting Equipment: CAT 326E Excavator
I
o Date Started: 4/3119 GPS Coordinates: Not Available Note: See Legend for Explanation of Symbols
G RD TEST PIT TP-17 II
APR.2019 JOB NO.5970-K FIG.18A
I
CLASSIFICATION OF MATERIAL d o• MOISTURE CONTENT,%
— z ❑ FINES CONTENT,%
LL
_ _ _ ��LIQUID LIMIT,% COMMENTS AND
1 a ,_ a a PLASTIC LIMIT,
W W ¢ ADDITIONAL TESTS
I o Surface Elevation: Not Available 0 50 100
/7 Silty CLAY to clayey SILT,trace fine-grained sand,brown,
medium stiff,contains organics,4-in.-thick heavily rooted
zone at ground surface(Residual Soil)
*0.30
II 5—/
_10/74 .
BASALT, ra and black, redominantl decom osed to - 11.0
g y P y P 11.5
decomposed,extremely soft to medium hard(RO to R3)
(Columbia River Basalt)
_ (4/3/2019)
Groundwater not encountered
15—
I
III 20_
—
I-
0
U, —
I Lai
a 25—
w
H — .
IU
W
J
W
iZ
30 c.9 0 0.5 1.0
I c7 • TORVANESHEARSTRENGTH,TSF
0
r
Logged By: M.Rauthause Excavated by: Benchmark Contracting Equipment: CAT 326E Excavator
0 Date Started: 4/3/19 GPS Coordinates: Not Available Note: See Legend for Explanation of Symbols
I G R 0 TEST PIT TP-18
IAPR.2019 JOB NO.5970-K FIG.19A
I
GROUP UNIFIED SOIL CLASSIFICATION GROUP UNIFIED SOIL CLASSIFICATION I
SYMBOL FINE-GRAINED SOIL GROUPS SYMBOL FINE-GRAINED SOIL GROUPS
ORGANIC SILTS AND ORGANIC SILTY ORGANIC CLAYS OF MEDIUM TO HIGH
OL CLAYS OF LOW PLASTICITY OH PLASTICITY,ORGANIC SILTS
INORGANIC CLAYEY SILTS TO VERY FINE INORGANIC SILTS AND CLAYEY SILT
ML SANDS OF SLIGHT PLASTICITY MH
INORGANIC CLAYS OF LOW TO MEDIUM INORGANIC CLAYS OF HIGH PLASTICITY
CL PLASTICITY CH
60
50 CH I
I
40
0
X
w
30 CL •
u
J
d 1 20
F' MH or OH
10
CL-ML
ML or OL
0 I
0 10 20 30 40 50 60 70 80 90 100
LIQUID LIMIT, % 1
Location Sample Depth,ft Classification LL PL PI MC, %
Silty CLAY,trace fine-grained sand, brown,
• B-5 S-2 2.5 contains organics (Residual Soil) 52 23 29 20
cn
Clayey SILT,trace fine-grained sand, brown
o B-6 S-2 5.0 mottled gray, contains organics (Residual Soil) 46 28 18 30
O
I-
a I
I-
r
w
a
W GRD
a
N
U
PLASTICITY CHARTre
I
U
m
w
APR.2019 JOB NO. 5970-K FIG. 20A
I
1 0
I 5
I
10
ce
15
I
f
20
I
I 25
0.01 0.1 1 10 100
STRESS, TSF
I
a Initial
Location Sample Depth,ft Classification 44,pcf MC,%
Silty CLAY to clayey SILT,trace fine-grained sand, brown,
• B 4 S-1 3.0 90 22
contains organics(Residual Soil)
o.
w
a
g GRBI
111
CONSOLIDATION TEST
J
I8 APR. 2019 JOB NO.5970-K FIG. 21A
I
o -- I
1
5
I
10 1
0
z
cc
H
V
15
1
1
20
I
I
25 I 0.01 0.1 1 10 100
STRESS,TSF
Initial I
o Location Sample Depth,ft Classification Yd,pcf MC, %
Silty CLAY to clayey SILT, trace fine-grained sand, brown,
• B-10 S-1 4.2 93 24
contains organics(Residual Soil)
IL
w
0
a
w
a
GR
0
O
0,
CONSOLIDATION TEST I
J
0
N
APR. 2019 JOB NO.5970-K FIG. 22A 111
KEY TO TEST PIT AND BORING LOG SYMBOLS
1 SYMBOL SAMPLING DESCRIPTION
1 Ill Location of sample obtained in general accordance with ASTM D 1 586 Standard Penetration Test
with recovery
Location of sample obtained using thin wall, shelby tube, or Geoprobee sampler in general
accordance with ASTM D 1 587 with recovery
1 Location of sample obtained using Dames & Moore sampler and 300-pound hamrner or pushed
with recovery
ILocation of sample obtained using Dames & Moore sampler and 140-pound hamrner or pushed
with recovery
I
CI Graphic Log of Soil and Rock Types
Location of grab sample ..,,: Observed contact
,.'.
I
between soil or rock units
`'' (at depth indicated)
Rock coring interval
I
Inferred contact between
Q Water level duringdrillingsoil or rock units
_ (at approximate depths
. indicated)
I1 Water level taken on date shown ;-:'
GEOTECHNICAL TESTING EXPLANATIONS
PP Pocket Penetrometer DD Dry Density
TOR Torvane ATT Atterberg Limits
CON Consolidation CBR California Bearing Ratio
I DS Direct Shear OC Organic Content
P200 Percent Passing U.S. Standard No. 200 P Pushed Sample
Sieve
RES Resilient Modulus
HYD Hydrometer Gradation
VS Vane Shear
UC Unconfined Compressive Strength
kPa kiloPascal
I SIEV Sieve Gradation
a
i ENVIRONMENTAL TESTING EXPLANATIONS
ro CA Sample Submitted for Chemical Analysis ND Not Detected
d
IPID Photoionization Detector Headspace Analysis NS No Visible Sheen
ppm Parts Per Million SS Slight Sheen
MS Moderate Sheen
I m P Pushed Sample
b HS Heavy Sheen
I 'ill
r G EO DESIGN=E 15575 SW Sequoia Parkway Suite 100 KEY TO TEST PIT AND BORING LOG SYMBOLS TABLE A-1
tland
I LL 68 8787 OR 97224
z
v Off 503368.8787 Fax 503.966.3068
SOIL CLASSIFICATION SYSTEM I
CONSISTENCY-COARSE-GRAINED SOILS
Relative Density Standard Penetration Dames& Moore Sampler Dames&Moore Sampler
Resistance (140-pound hammer) (300-pound hammer)
Very Loose 0-4 0- 11 0-4
Loose 4- 10 11 -26 4- 10
Medium Dense 10- 30 26-74 10- 30
Dense 30- 50 74- 120 30-47
Very Dense More than 50 More than 120 More than 47
CONSISTENCY- FINE-GRAINED SOILS
Consistency Standard Penetration Dames& Moore Sampler Dames & Moore Sampler Unconfined Compressive
Resistance (140-pound hammer) (300-pound hammer) Strength (tsf)
Very Soft Less than 2 Less than 3 Less than 2 Less than 0.25
Soft 2 -4 3 -6 2 - 5 0.25 -0.50
Medium Stiff 4 -8 6- 12 5 -9 0.50- 1.0
Stiff 8- 15 12 -25 9- 19 1.0-2.0
Very Stiff 15 - 30 25 -65 19 - 31 2.0-4.0
Hard More than 30 More than 65 More than 31 More than 4.0
SOIL CLASSIFICATION NAME I
Name and Modifier Terms Constituent Percentage
GRAVEL,SAND >50%
sandy, gravelly 30- 50%
silty, clayey 15 - 50%
Coarse-grained some(gravel, sand) 15 -30%
some(silt, clay) 5 - 15%
trace(gravel, sand)
trace(silt,clay) <5%
CLAY, SILT >50%
silty,clayey 30- 50%
sandy,gravelly
Fine-grained some(sand, gravel) 15 - 30%
some(silt, clay)
trace (sand, gravel) 5 - 15%
trace(silt, clay)
PEAT 50- 100%
Organic organic(soil name) 15 - 50%
(soil name)with some organics 5 - 15%
MOISTURE CLASSIFICATION
m
Term Field Test
dry very low moisture, dry to touch
moist damp,without visible moisture
ki
o wet visible free water, usually saturated
s GRAIN SIZE CLASSIFICATION
e,
gDescription Sieve* Observed Size
boulders - >12"
cobbles - 3"- 12"
gravel coarse 0.75" 3" 0.75" 3"
41
3 fine #4-0.75" 0.19"-0.75"
t coarse #10-#4 0.079"-0.19"
t sand medium #40-#10 0.017"-0.079"
r, fine #200-#40 00029"-0.017"
fines <#200 <0.0029"
it
*Use of#200 field sieve encouraged
GEODESIGN=
• �ss]s sw Sequoia Parkway-srtrte ioo SOIL CLASSIFICATION SYSTEM AND GUIDELINES TABLE A-2
m Portland OR 97224
Z
y Off 803.968.8]8] Fax 503.968.3068
tr. 111
ROCK CLASSIFICATION GUIDELINES
IHARDNESS DESCRIPTION
I Extremely Soft (RO)Very Soft (Rl) Indented by thumbnail
Can be peeled by pocket knife or scratched with finger nail
Soft (R2) Can be peeled by a pocket knife with difficulty
IMedium Hard (R3) Can be scratched by knife or pick
Hard (R4) Can be scratched with knife or pick only with difficulty
IVery Hard (R5) Cannot be scratched with knife or sharp pick
WEATHERING DESCRIPTION
' Decomposed Rock mass is completely decomposed
Predominantly Decomposed Rock mass is more than 50%decomposed
IIModerately Weathered Rock mass is decomposed locally
Slightly Weathered Rock mass is generally fresh
IFresh No discoloration in rock fabric
JOINT SPACING DESCRIPTION
1 Very Close Less than 2 inches
Close 2 inches to 1 foot
IModerate Close 1 foot to 3 feet
Wide 3 feet to 10 feet
IVery Wide Greater than 10 feet
FRACTURING FRACTURE SPACING
I
Very Intensely Fractured Chips and fragments with a few scattered short core lengths
I Intensely Fractured 0.1 foot to 0.3 foot with scattered fragments intervals
Moderately Fractured 0.3 foot to 1 foot with most lengths 0.6 foot
0
Slightly Fractured 1 foot to 3 feet
Io Very Slightly Fractured Greater than 3 feet
Unfractured No fractures
I - HEALING DESCRIPTION
Cn
Not Healed Discontinuity surface, fractured zone, sheared material or filling not re-cemented
Partly Healed Less than 50%of fractured or sheared material
I Moderately Healed Greater than 50%of fractured or sheared material
Totally Healed All fragments bonded
G EODESIGN=
ss ssws y DoParkway-s Reioo ROCK CLASSIFICATION GUIDELINES TABLE A-3
I LL Portland OR 97224
z
a Off 503.966.8]8] Fax 503.968.3068
i L3 Z
DEPTH uu Q a Z ti
o- •MOISTURE
FEET a MATERIAL DESCRIPTION J ow w Q CONTENT% COMMENTS
u
w I— In
TP-1 0 50 100
II0.0 Medium stiff, brown SILT with trace
- ,rootlets; moist (2- to 4-inch-thick root r 0.8
zone, till zone to 0.75 foot). J
- Stiff to very stiff, brown-gray SILT with PP IS) •
PP PP= 3.0 tsf
z.s— trace fine sand; moist.
with orange brown iron nodules at 2.0 ® PP=2.0 tsf
feet
1 _ with trace subangular cobbles and single
s.o— boulder at 3.0 feet
grades to very stiff and dark brown with
trace fine to coarse gravel and single
_ boulder (12-inch diameter) at 4.0 feet
grades to stiff and brown with trace fine
7 5— sand at 4.5 feet
I 10.0-
No groundwater seepage observed
12 5 ® • to the depth explored.
Exploration completed at 12.5 feet. 12.5 No caving observed to the depth
I = explored.
15.0—
I TP 2 0 50 100
0.0 0 50 100
Stiff, brown SILT with trace rootlets;
moist (2- to 4-inch-thick root zone, till PP= 1.5 tsf
- zone to 1.0 foot). 1 o PP ® •
- Stiff, brown SILT with trace fine gravel
2.s— and roots; moist; black charcoal
fragments; subrounded to subangular PP ® • PP= 3.0 tsf
gravel. PP PP=4.0 tsf
1 r grades to very stiff to hard with orange
irS
s.o—
and gray mottles, black nodules, and Excavation becomes hard below
trace sand at 3.0 feet 5.0 feet.
N
cu
o 5— No groundwater seepage observed
1- to the depth explored.
:i r 1 grades to some subangular, weathered, 8.3 ® No caving observed to the depth
_ basalt cobbles at 8.0 feet f S 3 explored.
Extremely soft to very soft (RO Rl),
z 10.0— brown BASALT; decomposed to intensely
`7, - weathered; hard, angular gravel- to
o = boulder-size rock fragments.
Exploration completed at 8.5 feet due to
2.s— refusal on basalt.
= —
I-
cc
15.Q
u 0 50 100
Li.,
EXCAVATED BY:Den J.Fischer Excavating,Inc. LOGGED BY:KOU COMPLETED:06/19/06
cc
c. EXCAVATION METHOD:excavator(see report text)
I ° G EODESIGN�v TIGARDTUAL 1 5-01 TEST PIT
H 15575 SW Sequoia Parkway-Suite 100
w 68.787 Fax 50a JULY 2006 THORPE PROPERTY
F OH Portland503.968.8]B] Fax 503.968.3W8 TIGARD, OR FIGURE A-1
z
o 0= v w
DEPTH u Q a Z a •MOISTURE COMMENTS
FEET a MATERIAL DESCRIPTION >w0 I- M CONTENT%
w < I
z w H In
V
TP-3 0 50 100
0.0
o.o tk Medium stiff, dark brown SILT with trace11
L" rootlets; moist (topsoil, 4-inch-thick root 10 El
=0.5 tsf
- `zone). PP
- Very stiff, brown SILT with trace roots; PP ® • PP=2.25 tsf I
2.5— moist.
- becomes very stiff to hard and brown PP ® PP=4.0 tsf
_ with orange-gray mottles and trace sand Excavating becomes hard below
- at 3.0 feet 4.0 feet. I
5.0—
7.5— I
No groundwater seepage observed
Ii i Extremely soft to very soft (RO-R1), r 9'0 • to the depth explored.
10.0— (brown BASALT; decomposed to intensely I 9.5 No caving observed to the depth
weathered; hard, angular gravel-to explored.
- boulder-size rock fragments.
- Exploration completed at 9.5 feet due to I
refusal on basalt.
12.5—
I
1 5.0—
0 50 100
TP-4 1
0.0 ...} 0 50 oo
=1,. Soft to medium stiff, brown SILT; moist
",,(topsoil, 4-inch-thick root zone). — 1.0 PP PP=0.75 tsf
- Very stiff to hard, brown-red SILT with
- trace sand and rootlets; moist. PP ® PP= 3.0 tsf
2.5—
- grades to brown with orange and gray •
I
PP PP=4.0 tsf
x
mottles without rootlets at 3.5 feet ® • I
Excavating becomes hard below
o s.o 5.0 feet.
• -
a 1
F 7.5— No groundwater seepage observed
2 II I Extremely soft to very soft (RO-R1), 8° ® to the depth explored.
brown BASALT; decomposed to intensely 8.5 No caving observed to the depth
o (weathered; hard, angular gravel- to explored.
I
z• 10.0— boulder-size rock fragments.
u, - Exploration completed at 8.5 feet due to
o = refusal on basalt.
V
u. 12.5-
0
a I
H
Q• 1 5.0—
Q V 0 50 100
F
aEXCAVATED BY:Dan J.Fischer Excavating,Inc. LOGGED BY:KOU COMPLETED:06/19l06
0.
ee
a EXCAVATION METHOD:excavator(see report text)
ev
= TIGARDTUAL-15-01 TEST PIT
• G EODESIGN
k- 15575 SW Sequoia Parkway-Sulie 100
D Portland OR 97224 JULY 2006 THORPE PROPERTY FIGURE A-2 I
r Off 503.968.8787 Fax 503.969.3068 TIGARD,OR
Iu 1 Z
_O
~h Z -' •MOISTURE
DEPTHFEET d
u MATERIAL DESCRIPTION JLL'O w m CONTENT% COMMENTS
-J I— U.,
TP-5 50 100
II 0.0 Medium stiff, brown SILT with trace
organics (rootlets); dry to moist (2- to 4- 1.0
Inch-thick root zone, till zone to 1.0 pp PP= 3.0 tsf
- foo Very y). -
2.5— stiff to hard, brown to red SILT with PP
trace fine sand and fine roots; moist. PP El • PP= 3.5 tsf
PP 4.0 tsf
- with orange-gray mottles without
rootlets at 3.0 feet Excavating becomes hard below
5.0— 4.5 feet.
7.5—
10.0—
-
I No groundwater seepage observed
f I I Extremely soft to very soft (RO-R1), I l.s ® • to the depth explored.
12.5— (brown BASALT; decomposed to intensely I2.0 No caving observed to the depth
weathered; hard, angular gravel-to explored.
I - boulder-size rock fragments.
Exploration completed at 12.0 feet due
to refusal on basalt.
15.0—
i TP-6 o 50 100
0.0 o 50 100
Medium stiff, dark brown SILT with trace DO • DD= 81 pct
rootlets; dry to moist (2-to 4-inch-thick 07
- \root zone, till zone to 0.7 foot). pp PP=2.5 tsf
Very stiff, brown SILT with trace fine
2 5— roots; moist.
_ with orange-gray mottles at 3.0 feet pp PP= 3.5 tsf
I ® •
5.0-
0
n
w
a
❑ 7.5—
1-
a with trace fine sand below 8.0 feet
a
u 10.0—
z -
u
o No groundwater seepage observed
12.5 f I l I Extremely soft to very soft (RO-Rl), 12.0 ® to the depth explored.
Y (brown BASALT; decomposed to intensely 12.5 No caving observed to the depth
s - weathered; hard, angular gravel- to explored.
1 boulder-size rock fragments.
Exploration completed at 12.5 feet due
o s.o— to refusal on basalt.
s -
u 0 50 100
CEXCAVATED BY:Dan J.Fischer Excavating,Inc. LOGGED BY:KOU COMPLETED:06/19/06
cc
d EXCAVATION METHOD:excavator(see report text)
° v TIGARDTUAL-15-01 TEST PIT
G EODESIGN�
I— 15575 SW Sequoia Parkway-Suite 100
w Portland JULY 2006 THORPE PROPERTY FIGURE A 3
o so3s68.5;ea.e7e7 Fax 503.966.3069 TIGARD,OR
z I
DEPTH u <0- Z a •MOISTURE
FEET MATERIAL DESCRIPTION w w N 2 CONTENT% COMMENTS
a —I w QI
cc w I— t t
L.,
TP-7
0 50 100
0
'0 ,,, Medium stiff, dark brown SILT with traceI
li " rootlets; dry (topsoil, 2-inch-thick root 1 o
- `zone). pp PP= 3.0 tsf
- Very stiff to hard, brown SILT; moist.
2.5— grades to dark brown at 2.0 feetI
- ® •
- pp PP=3.5 tsf I
5.0—
7 5_ encountered single, weathered basalt I
boulder(weathered basalt clast, 24 x 18
x 8 inches) at 7.0 feet
No groundwater seepage observed
maExtremely soft to very soft (RO Rl), 9.8 ® to the depth explored.• No caving observed to the depth
Ibrown BASALT; decomposed to intensely 10•o explored.
weathered; hard, angular gravel- to 1
boulder-size rock fragments.
12 5— Exploration completed at 10.0 feet due
to refusal on basalt.
I
1 5.0—
0 50 100
TP-8
0 50 100
0"0 _A ditA Medium stiff, dark brown SILT with trace
-\to some organics and roots; moist r 0"8 pp PP= 2.0 tsf
VtopVery if. /
Very stiff to hard, brown SILT with trace
I
2.5— rootlets and roots; moist.
- few decomposed roots (4- to 5-inch •
- diameter) at 2.7 feet PP ® PP=3.0 tsf
I
without rootlets at 4.0 feet pp PP=3.5 tsf
Y
40 5.0—
O
N
with trace fine sand at approximately 6.0
_ feet ® •
z7.5— No groundwater seepage observed
Fe 8.3 ® to the depth explored.
Extremely soft to very soft (RU-R1), - No caving observed to the depth
Ibrown BASALT; decomposed to intensely B.s explored.
o to.o weathered; hard, angular gravel- to
z boulder-size rock fragments.
fo Exploration completed at 8.5 feet due to
o refusal on basalt. I
e5 12.5—
o
Ivl
H
P, 15.0—
u 0 50 100
r
u EXCAVATED BY:Dan J.Fischer Excavating,Inc. LOGGED BY:KOU COMPLETED:06/19/06
a
cc
a EXCAVATION METHOD:excavator(see report text)
TIGARDTUAL-1 5-01 TEST PIT I
G EODESIGNv�
H 15575 SW Sequoia Parkway-Suite 100
w PoiandOR9nza THORPE PROPERTY
1- Off 503968.8787 Fax 503.968.3068 DULY 2006 TIGARD,OR FIGURE A-4
I U Z
O
o F-F z m. •MOISTURE
DEPTHFEET a MATERIAL DESCRIPTION w w '- g CONTENT% COMMENTS
w
w I— N
u
TP-9 0 50 100
00 _, Medium stiff, dark brown SILT with trace
`to some organics and roots; moist 07 PP PP= 1.5 tsf
(topsoil, 2- to 4-inch-thick root zone).
= Stiff to very stiff, brown SILT; moist.
Z.S— pp ® • PP=2.0tsf
with trace roots (1- to 1%: inch diameter) r 3.2 • No groundwater seepage observed
`'I I tat 3.0 feet a o •
to the depth explored.
- Extremely soft to very soft (RO-R1), No caving observed to the depth
s.o— brown BASALT; decomposed to intensely explored.
weathered; hard, angular gravel-to
- boulder-size rock fragments.
I =5— Exploration completed at 4.0 feet due to
refusal on basalt.
111
mo—
ll 12.5—
i
15.0—
TP10 0 50 100
0 50 100
0.0 , - Medium stiff, dark brown SILT with trace
`to some organics and roots; moist 0.5
(topsoil, 2-inch-thick root zone).
— Very stiff, brown SILT with dark brown PP El PP =2.25 tsf
z.s— mottles; moist.
- with trace fine rootlets at 2.0 feet PP PP=3.25 tsf
uo
Uzi 5.0— •
with trace fine sand at 6.0 feet
I < •
° 7.5—
z
s
a
• 10.0—
u becomes red-brown at 10.0 feet 10 s No groundwater seepage observed
w I I Extremely soft to very soft (RO-R1), ® to the depth explored.
E brown BASALT; decomposed to intensely 11.o No caving observed to the depth
weathered; hard, angular gravel- to explored.
q 12.5— boulder-size rock fragments.
o -- Exploration completed at 11.0 feet due
= to refusal on basalt.
a
ci
H
1s.o—
o 50 100
Ld
EXCAVATED BY:Dan J.Fischer Excavating,Inc. LOGGED BY:KOU COMPLETED:06/19/06
t1
ce
i EXCAVATION METHOD:excavator(see report text)
° v TIGARDTUAL-1 5-01 TEST PIT
G EO DES IGN�
f 155755W Sequoia Parkway-Suite 100
w dOR97224 JULY 2006 THORPE PROPERTY
I- °"503.9ea.ozo68.8787 Fax 503968 3068 TIGARD,OR FIGURE A-5
z I
DEPTH o P.a z a •MOISTURE
FEET d MATERIAL DESCRIPTION w w W M CONTENT% COMMENTS
I
CC w I Son
—
V
TP-1 1
0.0 as, 0 50 100
_la3. Stiff, dark brown SILT with trace rootlets;
1
''2"v moist (topsoil, 4-inch-thick root zone). . 1 o PP= 1.5 tsf
Very stiff, brown SILT; moist. PP ® • PP=2.0 tsf
2.5—- with orange-gray mottles at 2.0 feet Pp PP=2.5 tsf I
5.0— 1
7.5— with trace fine sand at 7.0 feet I
• No groundwater seepage observed
10.0 t I Extremely soft to very soft (RO R1), 9.s to the depth explored.
brown BASALT; decomposed to intensely lo.o No caving observed to the depth
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APPENDIX C
SITE-SPECIFIC SEISMIC HAZARD STUDY
GENERAL
GRI completed a site-specific seismic-hazard study for the new Art Rutkin Elementary School in Portland,
Oregon. The purpose of this study was to evaluate the potential seismic hazards associated with regional
and local seismicity. The site-specific seismic hazard evaluation is intended to meet the requirements of the
2014 Oregon Structural Specialty Code (OSSC), which is based on the 2012 International Building Code
(IBC). Seismic design in accordance with the 2012 IBC is based on the American Society of Civil Engineers
(ASCE) Document 7-10, Minimum Design Loads for Buildings and Other Structures (ASCE 7-10). Our site-
specific seismic hazard evaluation was based on the potential for regional and local seismic activity, as
described in the existing scientific literature, and the subsurface conditions at the site, as disclosed by the
1 geotechnical explorations completed for the project. Specifically, our work included the following tasks:
1) A detailed review of available literature, including published papers, maps, open-file
reports, seismic histories and catalogs, and other sources of information regarding the
tectonic setting, regional and local geology, and historical seismic activity that might
have a significant effect on the site.
2) Compilation, examination, and evaluation of existing subsurface data gathered at the
site, including classification and laboratory analyses of soil samples. This information
was used to prepare a generalized subsurface profile for the site.
3) Identification of potential seismic sources appropriate for the site and characterization of
those sources in terms of magnitude, distance, and acceleration response spectra.
4) Office studies based on the generalized subsurface profile and controlling seismic
sources resulting in conclusions and recommendations concerning:
a. specific seismic events and characteristic earthquakes that might have a
significant effect on the project site;
b. the potential for seismic energy amplification and liquefaction or soil-strength
loss at the site; and
c. site-specific acceleration response spectra for design of structures at the site.
This appendix describes the work accomplished and summarizes our conclusions and recommendations.
GEOLOGIC SETTING
General
On a regional scale, the site lies at the northern end of the Willamette Valley, a broad, gently deformed,
north-south-trending topographic feature separating the Coast Range to the west from the Cascade Mountains
to the east. The site is located approximately 69 km inland from the rupture zone of the Cascadia Subduction
Zone (CSZ), an active convergent-plate boundary along which remnants of the Farallon Plate (the Gorda,
111 Juan de Fuca, and Explorer plates) are being subducted beneath the western edge of the North American
R c ,
continent. The subduction zone is a broad,eastward-dipping zone of contact between the upper portion of
the subducting slabs and the overriding North American Plate,as shown on Figure 1C.
On a local scale, the site is located in the Tualatin Basin, a large, well-defined, northwest-trending syncline
bounded by high-angle, northwest-trending, right-lateral strike-slip faults, some of which are considered to
be seismogenic. The geologic units in the area are shown on the Local Geologic Map, Figure 2C. The
distribution of nearby Quaternary faults is shown on the Local Fault Map, Figure 3C. Information regarding
the continuity and potential activity of these faults is lacking due largely to the scale at which geologic
mapping in the area has been conducted and the presence of thick, relatively young, basin-filling sediments
that obscure underlying structural features. Additional faults may be present within the basin, but clear
stratigraphic and/or geophysical evidence regarding their location and extent is not presently available.
Additional discussion regarding crustal faults is provided in the Local Crustal Event section below.
Because of the proximity of the site to the CSZ and its location within the Tualatin Basin, three distinctly
different sources of seismic activity contribute to the potential for the occurrence of damaging earthquakes.
Each of these sources is generally considered to be capable of producing damaging earthquakes. Two of
these sources are associated with the deep-seated tectonic activity related to the subduction zone; the third
is associated with movement on the local, relatively shallow structures within and adjacent to the Tualatin
Basin.
Subsurface and Geologic Conditions I
Published geologic mapping indicates the site is mantled with residual soils produced from the weathering
of the underlying Columbia River Basalt (Madin, 2004). These residual soils typically consist of brown to
red-brown silt and clay soils of relatively high plasticity that exhibit relict structures of the weathered rock.
The weathering profile of the basalt grades from residual soil to hard rock with increasing depth within a
given flow.
SEISMICITY
General
The available information indicates the potential seismic sources that may affect the site can be grouped into
three independent categories: subduction-zone events related to sudden slip between the upper surface of
the Juan de Fuca Plate and lower surface of the North American Plate, subcrustal events related to
deformation and volume changes within the subducted mass of the Juan de Fuca Plate, and local crustal
events associated with movement on shallow, local faults within and adjacent to the Portland Basin. Each
of these sources is considered capable of producing damaging earthquakes in the Pacific Northwest.
However, there are no historical records of significant (i.e., moment magnitude (Mw) >6.0) subcrustal or
intraslab earthquakes. Based on review of historical records and evaluation of U.S. Geological Survey
(USGS) National Seismic Hazard Maps(NSHMs),the two primary types of seismic sources at the site are the
megathrust CSZ and local crustal faults.
Cascadia Subduction Zone(CSZ)
Written Japanese tsunami records suggest a great CSZ earthquake occurred in January 1700 (Atwater et al.,
2015). Geological studies suggest great megathrust earthquakes have occurred repeatedly in the past 7,000
years (Atwater et al., 1995; Clague, 1997; Goldfinger et al., 2003; and Kelsey et al., 2005), and geodetic
studies (Hyndman and Wang, 1995; and Savage et al.,2000) indicate rate of strain accumulation consistent
G R D C-2
I
with the assumption that the CSZ is locked beneath offshore northern California, Oregon, Washington, and
southern British Columbia(Fluck et al., 1997;and Wang et al.,2001). Numerous geological and geophysical
studies suggest the CSZ may be segmented(Hughes and Carr, 1980;Weaver and Michaelson, 1985;Guffanti
and Weaver, 1988; Goldfinger, 1994; Kelsey and Bockheim, 1994; Mitchell et al., 1994; Personius, 1995;
Nelson and Personius, 1996; and Witter, 1999), but the most recent studies suggest for the last great
earthquake in 1700, most of the subduction zone ruptured in a single Mw 9 earthquake (Satake et al., 1996;
Atwater and Hemphill-Haley, 1997;and Clague et al.,2000). Published estimates of the probable maximum
size of subduction-zone events range from Mw 8.3 to >Mw 9. Numerous detailed studies of coastal
subsidence, tsunamis, and turbidites yield a wide range of recurrence intervals, but the most complete
records (>4,000 years) indicate intervals of about 350 to 600 years between great earthquakes on the CSZ
(Adams, 1990; Atwater and Hemphill-Haley, 1997; Witter, 1999; Clague et al., 2000; Kelsey et al., 2002;
Kelsey et al., 2005; and Witter et al., 2003). Tsunami inundation in buried marshes along the Washington
and Oregon coast and stratigraphic evidence from the Cascadia margin support these recurrence intervals
(Kelsey et al.,2005;and Goldfinger et al.,2003). Goldfinger et al.(2003,2012,and 2016)evaluated turbidite
evidence for 20 earthquakes that ruptured the entire CSZ over the past 10,000 years and about 20 Mw 8
earthquakes that only ruptured along the southern portion of the CSZ and developed a model for recurrence
1 of CSZ Mw 8 to Mw 9 earthquakes.
The USGS probabilistic analysis assumes four potential locations (three alternative down-dip edge options
and one up-dip edge option)for the eastern edge of the earthquake rupture zone for the CSZ, as shown on
Figure 4C. As discussed in Petersen et al. (2014), the 2014 USGS mapping effort represents the 2014 CSZ
source model with the full CSZ ruptures with moment magnitudes from Mw 8.6 to Mw 9.3 supplemented by
' partial ruptures with smaller magnitudes from Mw 8.0 to Mw 9.1. The partial ruptures were accounted for
using a segmented model and unsegmented model. The magnitude-frequency distribution showing the
contributions to the earthquake rates from each of the models and how the rates vary along the fault is
presented on Figure 5C. In general, the earthquake rates along the CSZ are dominated by the full-
characteristic CSZ ruptures, with one event in 526 years (Mw 8.6 to Mw 9.3 earthquakes likely occur more
often than the smaller,segmented ruptures). Therefore, in our opinion,the CSZ event should be represented
by an earthquake of Mw 9.0 at a focal depth of 30 km and a rupture distance of about 69 km.
Local Crustal Event
Sudden crustal movements along relatively shallow, local faults in the project area,although rare,have been
responsible for local crustal earthquakes. The locations of and general information regarding Quaternary
faults(i.e.,those that have experienced movement during the last 2.6 million years and are considered to be
potentially active) are available through the USGS Earthquake Hazards Program. The precise relationship
between specific earthquakes and individual faults is not well-understood since few of the faults in the area
are expressed at the ground surface and the foci of the observed earthquakes have not been located with
precision. The history of local seismic activity is commonly used as a basis for determining the size and
frequency to be expected of local crustal events. Although the historical record of local earthquakes is
relatively short(the earliest reported seismic event in the area occurred in 1920), it can serve as a guide for
estimating the potential for seismic activity in the area.
Based on fault mapping conducted by the USGS (USGS,2014),there are about seven faults within 25 km of
the project site: the Canby-Mollala Fault at about 5 km from the site,the Bolton Fault at about 12.2 km from
the site,the Helvetia Fault at about 13.4 km from the site;the Newberg Fault at about 13.4 km from the site,
C-3
I
the Portland Hills Fault at about 17.1 km from the site, the Gales Creek Fault Zone at about 24 km from the
site, and the Grant Butte Fault at about 24.8 km from the site. However, the USGS only considers the
Portland Hills Fault to be an active,contributing source in their Probabilistic Seismic Hazard Analysis(PSHA).
The Portland Hills Fault is considered to be a reverse fault that dips to the southwest,with a total fault length
of approximately 50 km and a characteristic earthquake magnitude of Mw 7.0. Based on our review of the
USGS Quaternary Fault and Fold Database of the United States, it is our opinion a seismic event occurring I
on the Portland Hills Fault should be represented by a source-to-site distance of approximately 17.1 km and
a corresponding characteristic earthquake magnitude of Mw 7.0.
CODE BACKGROUND AND DESIGN RESPONSE SPECTRUM
General
The ASCE 7-10 seismic hazard levels are based on a Risk-Targeted Maximum Considered Earthquake(MCER)
with the intent of including the probability of structural collapse. Based on generalized building fragility
curves,seismic design of a structure using the probabilistic MCER represents a targeted risk level of 1% in 50
years probability of collapse in the direction of maximum horizontal response. In general,these risk-targeted
ground motions are developed by applying adjustment factors of directivity and risk coefficients to the 2%
probability of exceedance in 50 years (2,475-year return period hazard level) ground motions developed
from the 2008 USGS probabilistic seismic hazard maps. The risk-targeted probabilistic values are also
subject to a deterministic check, which is computed from the models of earthquake sources and ground-
motion propagation that form the basis of the 2008 USGS NSHMs. ASCE 7-10 defines the site-specific
deterministic MCER ground motions in terms of 84th-percentile, 5%-damped response spectral acceleration
in the direction of maximum horizontal response. The MCER ground motions are taken as the lesser of the
probabilistic and deterministic spectral accelerations. 1
Site Response
The ASCE 7-10 design methodology uses two spectral response acceleration parameters, Ss and Si,
corresponding to periods of about 0.2 and 1.0 second to develop the MCER response spectrum for Site Class
B/C, or bedrock conditions. The Ss and Si parameters for the site located at the approximate latitude and
longitude coordinates of 45.4071° N and 122.8454° W are 0.95 and 0.42 g, respectively. To establish the
ground-surface MCER spectrum,these bedrock spectral parameters are adjusted for underlying soil conditions
at the site using the short-and long-period site amplification coefficients, Fa and F . Based on the results of
the explorations completed for this project, the soil profile at the site is representative of Site Class C
conditions. Site coefficients Fa and Fyof 1.02 and 1.38, respectively, were used to develop the Site Class C
ground-surface MCER response spectra. The design response spectrum in accordance with ASCE 7-10 is
developed by taking two-thirds of the MCER response spectrum. 1
The MCER and design response spectral values are tabulated below.
RECOMMENDED MCERAND DESIGN RESPONSE SPECTRA,5%DAMPING 1
Period, MCER-Level Design-Level
seconds Response Spectral Values,g Response Spectral Values,g
0.01 0.44 0.29
0.12 0.97 0.65
0.60 0.97 0.65
G Rp C-4
1
I
IPeriod, MCEa-Level Design-Level
seconds Response Spectral Values,g Response Spectral Values, g
0.80 0.73 0.49
1.00 0.58 0.39
2.00 0.29 0.19
I3.00 0.19 0.13
4.00 0.15 0.10
ICONCLUSIONS
The ASCE 7-10 design methodology uses two mapped spectral acceleration parameters, Ss and Si,
I corresponding to periods of 0.2 and 1.0 second to develop the MCER earthquake. The Ss and Si parameters
for the site located at the approximate latitude and longitude coordinates of 45.4071° N and 122.8454° W
are 0.95 and 0.42 g, respectively. We recommend use of the Site Class C design spectrum for design of the
Iproposed improvements.
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I Clague, J. J., Atwater, B. F., Wang, K., Wang, Y., and Wong, I., 2000, Penrose conference report—Great Cascadia earthquake
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G RI
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Petersen,M.D.,Moschetti,M.P.,Powers, P.M.,Mueller,C.S.,Haller,K.M.,Frankel,A.D.,Zeng,Y.,Rezaeian,S.,Harmsen,S.C.,
Boyd, O. S., Field, N., Chen, R., Rukstales, K. S., Nico, L., Wheeler, R. L., Williams, R. A., and Olsen, A. H., 2014,
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tsunami records of January 1700: Nature,vol.379,pp.246-249.
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at Cape Blanco,Oregon: Journal of Geophysical Research,vol. 105,no.B2,pp.3,095-3,102.
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subduction zone: Earth, Planets,and Space,vol.53,pp.295-306.
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Juan de Fuca PI.: Geophysical Research Letters,vol. 12,no.4,pp.215-218.
Witter, R. C., 1999, Late Holocene Paleoseismicity, tsunamis and relative sea-level changes along the south-central Cascadia
subduction zone,southern Oregon:University of Oregon,unpublished PhD dissertation, 178 p.
Witter,R.C.,Kelsey,H.M.,and Hemphill-Haley,E.,2003,Great Cascadia earthquakes and tsunamis of the past 6700 years,Coquille
River estuary,southern coastal Oregon: Geological Society of America Bulletin,vol. 115,no. 10,pp. 1,289-1,306.
1
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f` —`' + ett n r.... �T , - 1987,GEOLOGICMAPOFWASHINGTON-SOUTHWESTQUADRANT;1:250,000:
' �'rt �t \ � � � Atii F= WASHINGTON DIVISION OF GEOLOGY AND EARTH RESOURCES,6Md4
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Y e•ti ' 0.:// , i • ` QT- :, WALKER,G.W.,AND MACLEOD,N.S.,1991,GEOLOGIC MAP OF OREGON:U.S.
3i' UAW ' ! I � I . j ., - .� � _�_ Ta 31 sdL GEOLOGICAL SURVEY
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0
1 Contact—Approximately located 1
-1-?—••• Fault—Dashed where inferred;dotted where concealed;queried where doubtful;ball and bar
I on downthrown side
? •A• Thrust fault—Dashed where inferred;dotted where concealed;queried where doubtful; REGIONAL GEOLOGIC MAP
sawteeth on upper plate
1 Strike and dip of bed APR.2019 JOB NO. 5970-K FIG. 2C
I
�: � O �� t Kelso , a - MAP EXPLANATION
`'•_—_, - - ` #, � OF MOST RECENT SURFACE RUPTURE STRUCTURE TYPE AND RELATED FEATURES
: \ z i
ME
" _ ^ t� a y_o- —TI Holocene(<10,000 years)or post last glaciakon <15,000 ears:15 ka Normal or high-angle reverse fault
a \" \ \ _ ' ` j r no historic ruptures in Oregon to date -r Strike-slip fault
Gearhart A -�` y# '`� Late Quaternary post penultimate glaciation) Thrust faun
L ''�` - r^ " ."-:,� Late and meddle Quaternary(<750,000 years,750 ka) —— Anticlinal fold
V
I SIde 1/ - (/` �! \� __ +-'"� J ary, ( years;<1.6 Ma) --t— Synclinal fold
l /O -� ; (g Quatern undMerenaated <1,600,000
✓p , `s' ° Class B structure(age or origin uncertain) �-- Monoclinal fold
_ �� � �� - .,,.. e4. i`'"- -, 1140 ,r arer 44* SLIP RATEI CD
�- Plunge direction of fold
\�\\ , vC/ F �. �t , .r a Fault section marker
1 4--,
- - t s�
1
3Ch ( 1 +� t .41....4S z `s i.0-5A mmyear
g 1-'1 f 718 r ^\ y,. ■y '�. 1 •,.. DETAILED STUDY SITES
.St. ens ft C ""ff 11 +. k, b 02-1.0m ear
pe nN 31-2 Trench site
k
r •,f , ` LL < \ _ ,. c02 mMyear7 81-z�� Subtluction zone study site
�`�,r -�'1\ O •, r / = TRACE
?m i. , 4 ,f. 1 _ . , f \ Mostly continuous at map wale CULTURALAND GEOGRAPHIC FEATURES
' to -'- ••';r�`k ` \ �i � y, ^f } �L' � ''`�t 580 Mostly discontinuous at map scale Divided highway
r.1 0` *.p �`• \ II0 4v.N i" 3 y, `\\ Interred or concealed Primary or secondary road
8 1-5 �t- �' I A �ilifb r '+•. -- -� _ - Permanent river or ll i
i • I �to + /� Intermittent river or stream
�t .-�. Vancouver
aCh - f••� I �I� _ - Pennanernorimerminentlake
Garibaldi pµ �,� {�* ; ;714 A. �� ��>;! 880 781 2 �\-- 867 k y
' Q ,...‘4.'...._:___ -_ . �� FAULT NUMBER NAME OF STRUCTURE
Bay City • ,�. �,�i �ti 876 � \ Rft'�` 714 HELVETIA FAULT
`V'•� r.f. �l' /6� �v ` , x '` �- _"— \NpOa 715 BEAVERTON FAULT
�.881 `:vim` =�1'; 875��. e '.- ' 878
?, r I. 11 �' r< S 7167 CANBY-MOLALLA FAULT
I 882 -- ��`_ �� ,,,,,,-,-4.,�' l 879 868. 86 717 NEWBERG FAULT
Tillarno9 \\' ��S ; ' ' `(( 718 GALES CREEK FAULT ZONE
' �Jl • `• •f71.. 719 SALEM-EOLA HILLS HOMOCLINE
)781-6 Y� ly���� ' 864 CLACKAMAS RIVER FAULT ZONE
_1 • ' liwr.Pj
Ali , 879 Portland
. 867 EAGLE CREEK THRUST FAULT
4 `/ 868 BULL RUN THRUST FAULT
�� -
Area of MOUNT 872 WALDO HILLS FAULT
��, 873 MOUNT ANGEL FAULT
i Aiplilirr ` ,�+ (' Portland map HOOD 874 BOLTON FAULT
McMinnvi �� - 875 OATFIELD FAULT
�_! p!'� �� �'� I 876 EAST BANK FAULT
78. H b,• . '• 1• 877 PORTLAND HILLS FAULT
878 GRANT BUTTE FAULT
Sheridan � )
a .rdburn I •lalla - 879 DAMASCUS-TICKLE CREEK FAULT ZONE
Amity 880 LACAMAS LAKE FAULT
_ 881 TILLAMOOK BAY FAULT ZONE
t• • 4 4
I 781 8 1 �j�I a• �� 873 FROM: PE RSONIUS,S.F.,AND OTHERS,2003,MAR OF UATERNARY FAULTS AND
�� �, �r� FOLDS IN OREGON,USGS OPEN FILE REPORT OFR-03-095.
e)
781 9 Dallas 'a - 719ti I-- Salem
1
Mgati
Independence 872 fkr 864
1 '�A 1 0 10 20 MILES
' �884 Monmouth Za ^ . —j 871 Stayton 4. 8!
i \ `71 .,_ 44
I 0 20 401KILOMETERS
I Mill City G
R 0
I LOCAL FAULT MAP
IAPR.2019 JOB NO. 5970-K FIG. 3C
I
128°W 126°W 124°W 122"W
\ �. ,-,# `ma's►
Y.. T�
1NI N.h....
1
. - N..cai 4.1\4424'\ 1
1 ii4:;17
i
1 r
I
Northern end of case B 44 t �
_ (7
I zv_ ll
IJ
ra
I N Northern end of case C fl
to
z z
I
v ` Northern end of case D v
lil• b• McCrory_5km
1 • Shallowest
::st
lil, -
in
1 Q • 2008 �1 ' .1 .
isi
Slab Contours i ! 1)
I
I II,0 50 100 200 300
I Kilometers♦ I 440
z \ ,
- I
1 Q 128`W 126°W 124°W 122"W
1 GRD
LOCATION OF SURFACE TRACES FOR UP-DIP
I
EDGE & THREE DOWN-DIP EDGE OPTIONS
USED IN 2014 NSHMS
(CHEN ET.AL 2014)
I
APR.2019 JOB NO. 5970-K FIG. 4C
I
50
i
49 '
48 '
47
N 46
v
tip
ti 4544
-
a
B
- Total rate
- Full CSZ rupture
43 Partial CSZ rupture,segmented
Partial CSZ rupture,unsegmented
42 '
41
40 '1 E-5 1E-4 1E-3 1E-2
Annual earthquake rate
REFERENCE:
PETERSEN,M.D.,MOSCHETTI,M.P.,POWERS,P.M.,MUELLER,C.S.,HALLER, K.M.,FRANKEL,A.D.,ZENG,Y.,REZAEIAN,S.,HARM-
SEN,S.C.,BOYD,O.S.,FIELD, N.,CHEN,R.,RUKSTALES,K.S., NICO, L.,WHEELER,R.L.,WILLIAMS,R.A.,AND OLSEN,A.H.,2014,
DOCUMENTATION FOR THE 2014 UPDATE OF THE UNITED STATES NATIONAL SEISMIC HAZARD MAPS: U.S.GEOLOGICAL SURVEY
OPEN-FILE REPORT 2014-1091,243 P.
1
GRD
VARIATION OF EARTHQUAKE RATES
CASCADIA SUBDUCTION ZONE (CSZ)
APR.2019 JOB NO. 5970•K FIG. 3C ,