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Draft Geotechnical Investigation
Report
Fields Apartments
SW Hunziker Street and SW Wall Street
Tigard, Oregon
OFFICE COPY
Prepared for:
DBG Properties LLC
Attn: Ms. Melora Banker
2164 SW Park Place
Portland, Oregon 97205
December 16, 2016
Project No. DBG-2016-003
RhinoOne Geotechmic& I 4610 NE 77th Avenue#126 Vancouver,WA 98662 I phone 360.2 8.1738
Geotechnical Investigation Report Fields Apartments
Tigard, Oregon
TABLE OF CONTENTS
1.0 INTRODUCTION 2
2.0 SITE CONDITIONS 2
Site Geology 2
Field Explorations 3
Laboratory Testing 3
Subsurface Conditions 3
Groundwater 4
3.0 GEOTECHNICAL DESIGN RECOMMENDATIONS 4
Discussion 4
Spread Footing Design Recommendations 4
Floor Slab Design Recommendations 5
Seismic Design Criteria 6
Retaining Wall Design Recommendations 6
MSE Walls 6
Other Concrete Retaining Walls 7
Drainage 7
Pavement Design Recommendations 8
Temporary Shoring Design Recommendations 9
4.0 CONSTRUCTION RECOMMENDATIONS 9
Site Preparation 9
Fills on Slopes 10
Slopes 10
Wet-Weather/Wet-Soil Conditions 10
Structural Fills 11
Native Soils 11
Imported Granular Fills 11
Trench Backfill 11
Retaining Wall Backfill 12
Trench Drain and Retaining Wall Drain Backfill 12
Floor Slab Base Rock 12
Pavement Base Aggregate 12
Recycled Concrete, Asphalt and Base Rock 12
Drainage Considerations 13
Foundation Drains 13
Excavation and Temporary Shoring 13
5.0 CONSTRUCTION OBSERVATIONS 14
6.0 LIMITATIONS 14
7.0 RESTRICTIONS 15
SUPPORTING DATA
Appendix A—Figures
Figure 1 Site Location Map
Figure 2 Site Exploration Plan
Appendix B—Summary Logs
Boring Logs
Results of Laboratory Testing
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1.0 INTRODUCTION
This report presents Rhino One Geotechnical's (ROG) geotechnical engineering study for the
proposed Fields Apartment complex located on an approximately 24 acre site (Washington County
Taxlot ID Number 2S1010001600) near the southwest corner of Southwest Hunziker Road and
Southwest Wall Street in Tigard, Oregon (Figure 1 — Site Location Map). The proposed plans are
for a nine-building 260 unit apartment complex with club house, associated parking, and other
miscellaneous improvements located in the southern portion of the lot. Additionally, an office
development is planned for the northern end of the lot. The scope of our work is limited to the
Apartment Complex.
Discussions with the structural engineer indicate the column and perimeter footings loads are on
the order of 200 kips and 6 kips per linear foot, respectively. We understand the site will be graded
to create flat lots for the buildings. Cuts and fills will therefore be on the order of 10 feet or less.
Retaining walls may be required at several locations of the site. Below grade structures are not
proposed at this time.
This report provides a summary of our field exploration, laboratory testing, geotechnical engineering
analysis, geotechnical design criteria, construction recommendations, and seismic design criteria
for the proposed project.
2.0 SITE CONDITIONS
Site Geology
Site geology at the project site was evaluated based on a review of geologic reports, site
reconnaissance, and subsurface explorations. Appendix A, Figure 2 (Site Exploration Plan) shows
the approximate locations of exploration for this project.
The site is located in the Tualatin Valley north of the Willamette River and south of the Tualatin
Mountains. The Tualatin Mountains form the physiographic boundary between the Portland Basin to
the east and the Tualatin Basin to the west. These basins are part of the larger Puget Sound-
Willamette Valley physiographic province, a tectonically active lowland situated between the Coast
Range to the west and the Cascade Mountains to the east'.
Basement rocks in the vicinity of the site are similar to those exposed in the adjacent Tualatin
Mountains, which primarily consist of the Miocene (20 million to 10 million years before present)
Columbia River Basalt Group (CRBG). The CRBG consists of thick flows of basalt which have been
folded and faulted from the compressional tectonics of the region.
Rivers flowing through the Portland Basin eroded channels through the uplifted basalts and
deposited alluvium in the adjacent valleys. The lower-most alluvium overlying the CRBG in the site
vicinity consists of the glacial-outburst Missoula Flood deposits, deposited approximately 15,500
and 12,500 years ago (Allen et al., 1986)2. Flood waters deposited fine-grained facies consisting of
fine sand, silt, and clay in the vicinity of the site.
The elevation at the site ranges from approximately 195 feet in the north near SW Hunziker Street,
235 feet near the eastern-center edge of the proposed development, to 180 feet along the southern
edge of the site. The surface topography at the site generally slopes towards the west. Existing
elevations were determined based on Google Earth maps and should be considered approximate.
1 Orr, E.L.and Orr,W.N. (1999). Geology of Oregon. Kendall/Hunt Publishing, Iowa. Page 254.
2 Allen,J.E., Burns, M.,and Sargent,S. (1986). Cataclysms on the Columbia.Timber Press, Portland. Page 211.
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Field Explorations
The subsurface exploration program for this project consisted of drilling two (2) borings using a
trailer-mounted drill rig and excavating five (5) test pits using a small tracked backhoe, both
operated by Dan J. Fischer Excavating, Inc. of Forest Grove, Oregon on November 17, 2016. The
borings and test pits were drilled /excavated at the approximate locations shown on the Site
Exploration Plan (Figure 2). The borings were advanced using continuous-flight auger drilling
techniques. The borings were drilled to a depth of 41.5 feet below ground surface (BGS). Standard
Penetration Test (SPT) soil samples were obtained at regular 2.5-foot intervals using a 140-pound
Automatic Hammer to a depth of 10 feet and at 5-foot intervals thereafter. Uncorrected blow counts
from the SPT sampling are reported on the boring logs. Corrected blow counts [(N1)60] were used
for our analysis unless otherwise noted. The five test pits were excavated using a standard hoe and
were excavated to a depth of 9.5 feet to 10.6 feet BGS. Bulk soil samples were obtained
periodically from the test pit excavated soil.
The subsurface materials encountered were logged and field classified in general accordance with
the Manual-Visual Classification Method (ASTM D 2488). The SPT and bulk samples were
collected at desired depths and packaged in moisture-tight bags. The soil samples were reviewed in
the laboratory in order to supplement field classifications. Interpreted borings and test pit logs are
attached.
Laboratory Testing
Laboratory tests were conducted on selected soil samples in accordance with standard ASTM
methods. The tests conducted include:
• Natural moisture content of selected samples obtained from the borings in general
accordance with guidelines presented in ASTM D2216.
• Atterberg Limits on selected samples obtained from the borings in general accordance with
guidelines presented in ASTM D4318.
The results of these tests are presented on the boring and test pit logs and in Appendix B.
Subsurface Conditions
Two borings and five test pits were completed across the site. The approximate boring locations are
shown on Figure 2 of Appendix A. Boring and test pit logs are attached in Appendix B. The borings
were drilled to depths of 41.5 feet BGS while the test pits were excavated to depths ranging from
9.5 feet to 10.6 feet BGS.
The site generally slopes from east to west and from the center to both south and north. The ground
cover of the site consists of grasses and mature trees in the north with blackberry bushes and
mature trees in the south. Tree stumps were observed among the blackberry bushes. Historical
images from 2011 show mature trees covering the entire site. Subsurface soils consist of the
following:
• The topsoil consists of sandy silt with a grass-root zone of 6 to 8 inches.
• The topsoil is underlain by medium stiff to very stiff, low to medium, clay or silt with varying
amounts of fine to medium sand to a depth ranging from 7.5 feet (B-3) to 10 feet BGS (B-7).
• The clay/silt was underlain by very loose to loose, low to no plasticity, silty fine to medium
sand to a depth ranging from 30 feet BGS (B-3) to 20 feet BGS (B-7).
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• The silty sand was underlain by medium stiff to very stiff, medium to high plasticity, silty clay
below a depth of 30 feet (B-3) to the maximum depth explored of 41.5 feet BGS in B-3.
The moisture contents of the samples are generally on the order of 25% to 40%.
Groundwater
Groundwater was encountered between 8 and 9.5 feet BGS at the time of drilling. Information
provided by the US Geological Survey (USGS) Estimated Depth to Groundwater Study of the
Portland Metro Area3, along with a review of existing well logs in the area, and the tested moisture
contents, indicate the groundwater table is shallow at depths less than 5 feet.
3.0 GEOTECHNICAL DESIGN RECOMMENDATIONS
Discussion
The proposed plans are for a nine-building 260 unit apartment complex with club house, associated
parking, access driveway and other miscellaneous improvements located in the southern portion of
the lot. Future developments may include an office building on the north side of the site.
The site generally slopes from east to west and from the center to both south and north. The ground
cover of the site consists of grasses and mature trees in the north with blackberry bushes and
mature trees in the south. Tree stumps were observed amongst the blackberry bushes. The topsoil
consists of sandy silt with a grass-root zone of 6 to 8 inches. The root zone for grasses, bushes,
and trees should be stripped in the location of the new buildings, roads, and other improvement
areas. The project owners should understand some additional over-excavation and replacement
may be required during construction if zones of deep roots are encountered during foundation
excavation. Any existing utilities below the proposed development areas should either be removed
or grouted full in place.
We understand the site will be graded to create flat lots for the buildings. We recommend that cuts
and fills be limited to 10 feet or less due to presence of shallow groundwater and potential slope
stability concerns. Please note, groundwater was encountered at a depth of 8 feet in boring B-3 and
9.5 feet in boring B-7. For cuts and fills greater than 10 feet, additional analysis and individual slope
design may be required. Proper drainage may be needed for planned cuts deeper than 5 feet. Un-
supported cuts and fills should be limited to slopes of 2H: 1V or flatter. Retaining walls may be
required at several locations of the site where these slopes cannot be achieved. We recommend
you provide us with a site grading plan when available so we can review these cuts, fills, and
retaining walls.
Discussions with the structural engineer indicate the column and perimeter footings loads are on
the order of 200 kips and 6 kips per linear foot, respectively. Below grade structures are not
proposed at this time. These structures can be supported on shallow spread footings.
We have provided geotechnical recommendations in the following section of this report which
should be incorporated into the design and construction of the proposed new development.
Spread Footing Design Recommendations
The native soils or the fill prepared in accordance with our recommendations are suitable for
support of spread footings. Continuous wall and isolated spread footings should be at least 18 and
24 inches wide, respectively. The bottom of exterior footings should be at least 18 inches below the
3 US Geological Survey(USGS).Estimated Depth to Ground Water in the Portland, Oregon Area.Accessed from website
http://or.water.us s..ov/.ro"s dir/ouzi on December 12,2015.
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lowest adjacent exterior grade. The bottom of interior footings should be established at least 12
inches below the base of the floor slab.
Footings bearing on frim native soils should be sized for an allowable bearing capacity of 2,000 psf.
This is a net bearing pressure. The weight of the footing and overlying backfill can be disregarded in
calculating footing sizes. The recommended allowable bearing pressure applies to the total of dead
plus long-term-live loads, and this bearing pressure may be doubled for short-term loads such as
those resulting from wind or seismic forces.
Based on our analysis, total post-construction settlements were calculated to be less than 1-inch,
with post-construction differential settlement of less than 0.5-inch over a 50-foot span for maximum
column and perimeter footing loads of less than 200 kips and 6 kips per linear foot. Also, due to the
silty nature of these soils, the settlement's will occur fairly rapidly as the loads are applied.
Lateral loads on footings can be resisted by passive earth pressure on the sides of the structures
and by friction at the base of the footings. An allowable passive earth pressure of 200 pounds per
cubic foot (pcf) may be used for footings confined by native soils. Adjacent floor slabs, pavements,
or the upper 24 inch depth of adjacent, unpaved areas should not be considered when calculating
passive resistance. For footings in contact with native material, use a coefficient of friction equal to
0.35 when calculating resistance to sliding. Both of these numbers include a factor of safety of 1.5.
The footings should be founded below an imaginary line projecting at a 1-horizontal to 1-vertical
(1 H: 1V) slope from the base of any adjacent, parallel utility trenches. The footings must be
embedded so there is a minimum of 10 feet of horizontal distance between the base of the footings
and any adjacent slope. In wet-weather, a 2 to 4 inch layer of granular material may be required at
the footing base to provide a firm surface for the construction of the new footings.
A geotechnical engineer or their representative from ROG should confirm suitable bearing
conditions and evaluate footing subgrades. Observations should also confirm loose or soft material,
organics, unsuitable fill, and old topsoil zones were removed. Localized deepening of excavations
may be required to penetrate deleterious or unsuitable fill materials. The resulting excavations
should be backfilled with granular material.
Floor Slab Design Recommendations
For on-grade slabs on native soils, we recommend a 6-inch-thick layer of imported granular material
should be placed and compacted over the prepared subgrade. Imported granular material should
be crushed rock or crushed gravel and fairly well-graded between coarse and fine, contain no
deleterious materials, have a maximum particle size of 1-inch, and have less than 5-percent by
weight passing the U.S. Standard Number 200 Sieve. This material should meet recommendations
for "Floor Slab Base Rock" provided in Section 4. A subgrade modulus of 100 pounds per cubic
inch (pci) may be used to design the floor slab.
The design team should evaluate whether a vapor barrier is needed. A vapor barrier will reduce the
potential for moisture transmission through and efflorescence growth on the floor slabs.
Additionally, flooring manufacturers often require vapor barriers to protect flooring and flooring
adhesives and will warrant their product only if a vapor barrier is installed according to their
recommendations. Actual selection and design of an appropriate vapor barrier, if needed, should be
based on discussions among members of the design team.
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Seismic Design Criteria
The seismic design criteria for this project are based on the IBC 2012 (OSSC 2014). A soil profile
type "D" can be used for the seismic design of the building based on our exploration. The seismic
design criteria, in accordance with the 2012 IBC (OSSC 2014) are summarized in the table below.
The code specified IBC Spectra can be used for the design of this building.
Table 1 IBC 2012 (OSSC 2014) Seismic Design Parameters
Short Period 1 Second
Maximum Credible Earthquake Spectral Acceleration SS = 0.973 g Si = 0.422 g
Site Class D
Site Coefficient Fa= 1.111 F„= 1.578
Adjusted Spectral Acceleration SMG = 1.081 g SM, = 0.666 g
Design Spectral Response Acceleration Parameters Sps = 0.720 g SDI = 0.444 g
Design Spectral Peak Ground Acceleration 0.283 g
Additional Parameters for Liquefaction Analysis per ASCE 7-10, Section 11.8.3
Mapped MCEG Peak Ground Acceleration PGA = 0.425 g
Site Coefficient FPGA= 1.075
MCEG Peak Ground Acceleration Adjusted for Site Class PGAM = 0.457 g
Groundwater is interpreted at depths on the order of 8 to 9.5 feet BGS. The soils at this site are
medium stiff to stiff clayey silt over loose silty sand. The loose silty sands below the water table are
moderately susceptible to liquefaction or earthquake-induced settlement during a design level
seismic event. The associated vertical settlements could be on the order of 2 to 4 inches during a
design level seismic event. Other potential geologic and seismic hazards such as earthquake
induced slope instability, differential settlement, surface displacement due to faulting or lateral
spreading, and tsunami or seiche inundation are relatively low at this site.
Retaining Wall Design Recommendations
Retaining walls may be required for accomplishing cuts and fill at the site where adequate slopes
cannot be maintained. The retaining walls can be Mechanically Stabilized Earth walls (MSE), typical
concrete walls, soil nail walls, or soldier pile walls. At this point, we are not aware of any soil nail or
soldier pile walls on this project. These wall types are therefore not discussed any further. We have
discussed MSE walls and typical concrete retaining walls below.
MSE Walls
This section provides general recommendations for the design of MSE walls. MSE walls shall have
a minimum reinforcement length of 70 percent of the MSE wall height or 8 feet, whichever is
greater. MSE walls shall have a toe embedment equal to 10 percent of the wall height or 2 feet,
whichever is greater. The MSE walls should be evaluated for bearing capacity, sliding, overturning,
and global stability under static and seismic (pseudo-static) conditions. The MSE walls should be
designed using the parameters provided in Table 2.
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Table 2 Structural Earth Wall Design Parameters
Soil Properties Wall Backfill' Retained Soil2 Foundation Soil3
Unit Weight(pcf) 135 110 110
Friction Angle(degree) 35 28 30
Cohesion (psf) 0 0 0
Bearing Capacity(ksf) n/a n/a 5
Acceleration Coefficient,A(g) =2/3 PGAM =0.31
"Wall backfill"shall meet the requirements of"Retaining Wall Backfill"section of this report.
2"Retained soil"shall meet the requirements of ODOT-SS 00330.12—Borrow Material and 00330.13—
Selected General Backfill.
3"Foundation soil"shall be dense,native soils prepared in conformance with the"Site Preparation"section of this
report.
Other Concrete Retaining Walls
The retaining wall design recommendations are based on the following assumptions: (1) the walls
consist of conventional, cantilevered retaining walls; (2)the walls are less than 10 feet in height; (3)
the backfill is drained; and (4) the backfill has a slope flatter than 4H:1 V. Review of our
recommendations will be required if the retaining wall design criteria for the project varies from
these assumptions.
Any unrestrained retaining walls required for the proposed construction should be designed to resist
an active pressure of 35 pounds per cubic foot (pcf) Equivalent Fluid Weight (EFW) in supporting
soils with retained slopes less than 4:1 (H:V). An active pressure of 60 pcf EFW should be used for
retained slopes with an inclination of 2:1 (H: V). Where retained slopes are greater than 4:1, though
less than 2:1, the designer should linearly interpolate between 35 and 60 pcf EFW. For restrained
retaining walls an EFW of 60 pcf should be used.
Lateral pressures may also be resisted by a passive pressure of 200 pcf EFW assumed to be acting
against the sides of the footings (or shear keys, if required). Passive resistance should start at a
depth of 1 foot below adjacent grade. For footings in contact with native material, use a coefficient
of friction equal to 0.35 when calculating resistance to sliding. Both of these numbers include a
factor of safety of 1.5.
All retaining walls should also be designed to account for any surcharge loads (e.g. footings,
vehicles, etc.) which are applied to the ground surface within a zone extending away from the back
of the wall a distance equal to the total height of the wall. Our office should be contacted for
appropriate surcharges to be applied to the back of the wall. The actual surcharge distribution and
magnitude on the wall will vary depending upon the size and location of the applied load.
Drainage
The design parameters provided assume back-of-wall drains will be installed in order to prevent
buildup of hydrostatic pressures behind all walls. A minimum 12-inch wide zone of drain rock,
extending from the base of the wall to within 6 inches of finished grade, should be placed against
the back of all retaining walls. Perforated collector pipes should be embedded at the base of the
drain rock. The perforated collector pipes should discharge at an appropriate location away from the
base of the wall. The backfill material placed behind the walls and extending a horizontal distance
equal to at least the height of the retaining wall should consist of granular retaining wall backfill
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material meeting specifications provided in Oregon's Department of Transportation Standard
Specifications for Construction 2015 (ODOT-SS) Section 510.12. We recommend the select
granular wall backfill be separated from general fill, native soil and/or topsoil using a geotextile
fabric which meets the requirements provided in ODOT-SS 2320.20 for drainage geotextiles. The
wall backfill should be compacted to a minimum of 92 percent of the maximum dry density, as
determined by ASTM D 1557. Backfill placed within 3 feet of the wall should be compacted in lifts
less than 6 inches thick using hand-operated tamping equipment (e.g., jumping jack or vibratory
plate compactors).
Settlements of up to 1% of the wall height commonly occur immediately adjacent to the wall as the
wall rotates and develops active lateral earth pressures. Consequently, we recommend construction
of flat work adjacent to retaining walls be postponed at least four (4) weeks after backfilling of the
wall, unless survey data indicates settlement is complete prior to that time.
Pavement Design Recommendations
Our pavement recommendations are based on the following assumptions:
• A resilient modulus of 4,500 psi for the native site soils.
• A resilient modulus of 20,000 psi estimated for the base rock.
• Initial and terminal serviceability index of 4.2 and 2.5, respectively.
• Reliability and standard deviation of 85% and 0.45, respectively.
• Structural coefficient of 0.42 and 0.10 for the asphalt and base rock, respectively.
• We assumed several Equivalent Single Axle Loads (ESALs) for pavement design. The
actual ESALs should be selected based on traffic levels anticipated as the project moves
forward.
If any of these assumptions are incorrect, contact our office with the appropriate information so we
may revise the pavement designs. Pavement designs were based on the 1993 AASHTO pavement
design equations. The development of pavement designs for the project pavements are in general
accordance with the design guidelines and procedures of the American Association of State
Highway and Transportation Officials (AASHTO) and the Oregon Department of Transportation
(ODOT) Pavement Design Manual. Summary of our pavement design recommendations are in the
table below.
Table 3 Minimum Pavement Sections
Traffic Loading Asphalt Cement Aggregate Base
(ESALs) Concrete Rock
(inch) (inch)
10,000 (Parking Lots) 3 8
50,000 (Driveways) 4 10
The thicknesses shown in Table 3 are intended to be minimum acceptable values.
The asphalt cement (AC) binder should be PG 64-22 Performance Grade Asphalt Cement
according to ODOT-SS 00744.11 —Asphalt Cement and Additives. The AC should consist of dense
graded Level 3, 1/2-inch hot mix asphalt. The minimum lift thicknesses should be 2.0 inches. The AC
should conform to ODOT-SS 00744.13 and be compacted to 91% of Rice Density of the mix, as
determined in accordance with ASTM D 2041.
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The pavement subgrade should be prepared in accordance with the "Site Preparation" and
"Structural Fill" sections of this report.
Construction traffic should be limited to non-building, unpaved portions of the project site or haul
roads. Construction traffic should be prohibited on new pavements. If construction traffic is
allowable on newly constructed road sections, an allowance for this additional traffic is necessary in
the design pavement section.
If moist soil conditions make it difficult to properly moisture condition and compact the roadway
subgrade, the use of cement amendment should be considered as alternative to moisture
conditioning and compaction. The use of cement amendment will allow for construction of the
pavement sections without disturbing the sensitive soil subgrade. If this method is chosen, contact
ROG for additional recommendations and alternative pavement sections.
Temporary Shoring Design Recommendations
Temporary shoring may be required for cuts greater than four feet deep. The selection and design
of the temporary shoring system is the responsibility of the contractor. We have provided the
following general guidelines for the design of temporary shoring.
For a cantilever type shoring system, use an active equivalent fluid weight (EFW) of 35 pounds per
cubic feet (pcf) and a passive EFW of 200 pcf. Neglect the upper 2 feet of soils immediately below
the base of excavation when calculating passive resistance. Groundwater is indicated to be at
depths on the order of 5 to 10 feet BGS. Perched groundwater may be present at shallower depths.
Additional pressure due to the presence of groundwater should be accounted for especially if
construction is in winter weather. Use a minimum of 2 feet of traffic surcharge load.
We are not aware of planned excavations deeper than 10 feet at this time. Additional
recommendations will be provided for deeper excavations if needed.
4.0 CONSTRUCTION RECOMMENDATIONS
The construction should be carried out as indicated in accordance with the Oregon Department of
Transportation Standard Specifications for Construction, 2015 version (ODOT-SS). We assume
these specifications will serve, in part, as the project specifications for items contained within and
for those not included in this report.
Site Preparation
The existing near-surface root zone should be stripped and removed from the project site in all
proposed building, fill, and pavement areas and for a 5-foot margin around such areas. We
anticipate an average stripping depth of 6 to 8 inches with some localized deeper areas. The actual
stripping depth should be based on field observations at the time of construction. Stripped material
should be transported off site for disposal or stockpiled for use in landscaped areas.
Trees and shrubs should be removed from all pavement and improvement areas. In addition, root
balls should be grubbed out to the depth of the roots, which could exceed 3 feet BGS. Depending
on the methods used to remove the root balls, considerable disturbance and loosening of the
subgrade could occur during site grubbing. We recommend soil disturbed during grubbing
operations be removed to expose firm undisturbed subgrade. The resulting excavations should be
backfilled with structural fill.
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Demolition should include removal of existing improvements throughout the project site.
Underground utility lines, vaults, basement walls, or tanks should also be removed or grouted full if
left in place. The voids resulting from removal of footings, buried tanks, etc. or loose soil in utility
lines should be backfilled with compacted structural fill. The base of these excavations should be
excavated to firm subgrade before filling with sides sloped at a minimum of 1 H:1 V to allow for
uniform compaction.
Materials generated during demolition of existing improvements should be transported off site or
stockpiled in areas designated by the owner. Asphalt, concrete, gravel fill, and base rock materials
may be crushed and recycled for use as general fill. Such recycled materials should meet the
criteria described in the "Structural Fill" section of this report.
Following stripping and prior to placing fill, pavement, or building improvements, the exposed
subgrade should be evaluated by proof rolling. The subgrade should be proof rolled with a fully
loaded dump truck or similar heavy rubber-tire construction equipment to identify soft, loose, or
unsuitable areas. A member of our geotechnical staff should observe the proof rolling. Soft or loose
zones identified during the field evaluation should be compacted to an unyielding condition or be
excavated and replaced with structural fill, as discussed in the "Structural Fill" section of this report.
Fills on Slopes
All unretained fills to be placed on slopes steeper than 6 to 1 (horizontal to vertical, H:V) will need to
be keyed and benched into competent native materials. Any retained fills will need to be benched in
competent native materials. The entire base of all benches should extend into or through competent
soils, as identified in the field by representatives from our office. It should be anticipated that the
outer edge of bench excavations will extend at least 1 foot below native grade. Keyways should be
at least 11/2 times as wide as the compaction equipment, with a width no less than 10 feet. Keyways
and benches should be sloped back into the hillside at a minimum 2% gradient.
For fills located in drainage swales or where deemed necessary by our personnel, subdrains should
be provided within the fill (generally at keyway excavations). Subdrains will typically consist of a
minimum 12-inch wide column of drain rock, wrapped with filter fabric, for at least half the height
and for the full width of the bench. These systems should drain to 4-inch diameter slotted or
perforated pipes, placed at the base of the drain rock. The drain pipes should consist of Schedule
40 PVC, SDR 35, or other similar pipe. Flexible, corrugated pipes should not be used within any
drainage system installed as part of this project. A solid line should be used to convey the water to
an appropriate discharge point.
Slopes
Cut slopes less than 10 feet tall and engineered fill slopes may have a maximum gradient of 2:1
(H:V). Cut slopes exceeding 10 feet tall should be approved by our office. Furthermore, we
recommend the crest of slopes be rounded (10 foot radius curvature) to reduce surficial sloughing.
Wet-Weather/Wet-Soil Conditions
Trafficability on the near-surface soils may be difficult during or after extended wet periods or when
the moisture content of the surface soil is more than a few percentage points above optimum. Soils
which have been disturbed during site-preparation activities, or soft or loose zones identified during
probing or proof-rolling, should be removed and replaced with compacted structural fill.
Track-mounted excavating equipment may be required during wet weather. The thickness of the
granular material for haul roads and staging areas will depend on the amount and type of
RhinoOne Geotechnical 14610 NE 77th Avenue#126 I Vancouver,WA 98662 I phone 360.258.1738
December 16,2016
Project DBG-2016-003
10
Geotechnical Investigation Report Fields Apartments
Tigard,Oregon
construction traffic. A 12 to 18 inch-thick mat of imported granular material is sufficient for light
staging areas. The granular mat for haul roads and areas with repeated heavy-construction traffic
typically needs to be increased to between 18 to 24 inches. The actual thickness of haul roads and
staging areas should be based on the contractor's approach to site development and the amount
and type of construction traffic. The imported granular material should be placed in one lift over the
prepared, undisturbed subgrade and compacted using a smooth-drum, non-vibratory roller.
Additionally, a geotextile fabric should be placed as a barrier between the subgrade and imported
granular material in areas of repeated construction traffic. The imported granular material should be
4-to 6-inch minus pit run rock with less than 5% passing a Standard #200 sieve.
Structural Fills
Fills should be placed over subgrade which has been prepared in conformance with the previous
section of this report. Material used as structural fill should be free of organic matter or other
unsuitable materials and should meet specifications provided in Oregon Department of
Transportation Standard Specifications for Construction, 2015 (ODOT-SS), depending upon the
application. Discussion of these materials is in the following sections.
Native Soils
The native soils are suitable for use as general fill, provided it is properly moisture conditioned and
meets the requirements of ODOT-SS 00330.12 — Borrow Material, and 00330.13 — Selected
General Backfill. When used as structural fill, native soils should be placed in lifts with a maximum
un-compacted thickness of 6 to 8 inches and compacted to not less than 92 percent of the
maximum dry density as determined by ASTM D 1557. Note that the moisture content of the
existing native material is on the order of 25% to 40% percent. This will require considerable
moisture conditioning for proper compaction.
Imported Granular Fills
Imported granular material should be pit or quarry run rock, crushed rock, or crushed gravel and
sand and should meet the specifications provided in ODOT-SS 00330.14— Selected Granular
Backfill, and ODOT-SS 00330.15 — Selected Stone Backfill. The imported granular material should
be fairly well graded between coarse and fine material and have less than 5% by weight passing
the U.S. Standard Number 200 Sieve.
Imported granular material should be placed in lifts with a maximum non-compacted thickness of 8
to 12 inches and be compacted to at least 92% of the maximum dry density, as determined by
ASTM D 1557. During the wet season or when wet subgrade conditions exist, the initial lift should
be approximately 18 inches in non-compacted thickness and should be compacted with a smooth-
drum roller without using vibratory action.
Where imported granular material is placed over wet or soft soil subgrades, we recommend a
geotextile be placed as a barrier between the subgrade and imported granular material. The
geotextile should meet ODOT-SS 2320.20 for soil separation and/or stabilization. The geotextile
should be installed in conformance with ODOT-SS 00350.40 — Geosynthetic Construction.
Trench Backfill
Trench backfill placed beneath, adjacent to, and for at least 2 feet above utility lines (i.e., the pipe
zone) should consist of well-graded, granular material with a maximum particle size of 1.5 inches,
have less than 10% by weight passing the U.S. Standard Number 200 Sieve, and meet ODOT-SS
405.12 - Pipe Zone Bedding. The pipe zone backfill should be compacted to at least 90% of the
RhinoOne Geotechnical 14610 NE 77th Avenue#126 I Vancouver,WA 98662 I phone 360.258.1738
December 16,2016
Project DBG-2016-003
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Geotechnical Investigation Report Fields Apartments
Tigard,Oregon
maximum dry density, as determined by ASTM D 1557 or as required by the pipe manufacturer or
local building department.
Within roadway alignments or beneath building pads, the remainder of the trench backfill should
consist of well-graded, granular material with a maximum particle size of 2.5 inches, have less than
10% by weight passing the U.S. Standard Number 200 Sieve, and meet ODOT-SS 405.14 - Trench
Backfill, Class B. This material should be compacted to at least 92% of the maximum dry density as
determined by ASTM D 1557, or as required by the pipe manufacturer or local building department.
The upper 2-feet of the trench backfill should be compacted to at least 95% of the maximum dry
density as determined by ASTM D 1557.
Outside of structural improvement areas (e.g., roadway alignments or building pads), trench backfill
placed above the pipe zone may consist of general fill materials that are free of organics and
materials over 6 inches in size, and meet ODOT-SS 405.14 - Trench Backfill, Class A, C, or D. This
general trench backfill should be compacted to at least 90% of the maximum dry density, as
determined by ASTM D 1557 or as required by the pipe manufacturer or local building department.
Retaining Wall Backfill
Backfill material placed behind retaining walls and extending a horizontal distance of 0.5H, where H
is the height of the retaining wall, should consist of select granular material meeting ODOT-SS
510.12 — Granular Wall Backfill. We recommend the select granular wall backfill be separated from
general fill, native soil and/or topsoil using a geotextile fabric which meets the requirements
provided in ODOT-SS 2320.20 for drainage geotextiles. The geotextile should be installed in
conformance with ODOT-SS 00350.40 — Geosynthetic Construction.
Trench Drain and Retaining Wall Drain Backfill
Backfill for subsurface trench drains and for a minimum 1-foot-wide zone against the back of
retaining walls should consist of drain rock meeting the specifications provided in ODOT-SS
00430.11 — Granular Drain Backfill Material. A pre-fabricated drain board can be substituted for the
drain rock. The drain rock should be wrapped in a geotextile fabric meeting the specifications
provided in ODOT-SS 2320.20 for soil separation and/or stabilization. The geotextile should be
installed in conformance with ODOT-SS 00350.40 — Geosynthetic Construction.
Floor Slab Base Rock
Base aggregate for floor slabs should be clean, crushed rock or crushed gravel. The base
aggregate should contain no deleterious materials, meet specifications provided in ODOT-SS
02630.10 — Dense Graded Aggregate 1"-0", and have less than 5% by weight passing the U.S.
Standard Number 200 Sieve. The imported granular material should be placed in one lift and
compacted to at least 95% of the maximum dry density, as determined by ASTM D 1557.
Pavement Base Aggregate
Imported base aggregate for roads and parking lots should be clean, crushed rock or crushed
gravel. The base aggregate should meet the gradation defined in ODOT-SS 02630.10— Dense
Graded Aggregate 1"-0," with the exception that the aggregate should have less than 5% passing a
U.S. Standard Number 200 Sieve. The base aggregate should be compacted to at least 95% of the
maximum dry density, as determined by ASTM D 1557.
Recycled Concrete, Asphalt and Base Rock
Asphalt pavement, concrete, and base rock from the existing site improvements can be used in
general structural fills, provided no particles greater than 6 inches are present. It also must be
RhinoOne Geotechnical I 4610 NE 77`h Avenue#126 I Vancouver,WA 98662 I phone 360.258.1738
December 16,2016
Project DBG-2016-003
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Geotechnical Investigation Report Fields Apartments
Tigard,Oregon
thoroughly mixed with soil, sand or gravel such that there are no voids between the fragments. In
addition this material should be non-hazardous.
Drainage Considerations
Newly exposed cut and fill slopes and subgrade surfaces will be susceptible to erosion and should
be re-vegetated or otherwise protected as soon as practical after construction. If it is anticipated
that an adequate vegetative cover may not be established before the onset of the winter wet
season, a heavy mulch cover or erosion netting may be necessary to minimize erosion.
Water should not be allowed to pond or stand on any graded pads. Areas that could allow ponding
water should be graded and sloped to drain. The surface runoff from graded areas should not be
allowed to drain over any slopes.
The Contractor shall be made responsible for temporary drainage of surface water and groundwater
as necessary to prevent standing water and/or erosion at the working surface. We recommend
removing only the foliage necessary for construction to help minimize erosion.
The ground surface around the structure should be sloped to create a minimum gradient of 2%
away from the building foundations for a distance of at least 5 feet. Surface water should be
directed away from all buildings into drainage swales or into a storm drainage system. "Trapped"
planting areas should not be created next to any building without providing means for drainage. The
roof downspouts should discharge onto splash blocks or paving which direct water away from the
buildings, or into smooth-walled underground drain lines that carry the water to appropriate
discharge locations at least 10 feet away from any buildings.
Foundation Drains
We recommend foundation drains around the perimeter foundations of all structures. The
foundation drains should be at least 12 inches below the base of the slab. The foundation drain
should consist of perforated collector pipes embedded in a minimum 2-foot-wide zone of angular
drain rock. The drain rock should meet specifications provided in the "Structural Fill" section of this
report. The drain rock should be wrapped in a geotextile fabric. The collector pipes should
discharge at an appropriate location away from the base of the footings. Unless measures are
taken to prevent backflow into the foundation's drainage system, the discharge pipe should not be
tied directly into storm water drain system.
Excavation and Temporary Shoring
Subsurface conditions at the project site show predominately silts and clays to the depths explored.
Excavations in these soils may be readily accomplished with conventional earthwork equipment.
Trench cuts should stand vertical to a depth of approximately 4 feet— provided no groundwater
seepage is present in the trench walls. Open excavation may be used to excavate trenches with
depths between 4 and 8 feet with the walls of the excavation cut at a slope of 1 H:1 V— provided
groundwater seepage is not present and with the understanding that some sloughing may occur.
The trenches should be flattened to 1.5H:1V if excessive sloughing occurs or seepage is present.
If shallow groundwater is observed during construction, use of a trench shield (or other approved
temporary shoring) is recommended for cuts extending below groundwater seepage or if vertical
walls are desired for cuts deeper than 4 feet. If shoring or dewatering is used, we recommend the
type and design of the shoring and dewatering systems be the responsibility of the contractor who
is in the best position to choose systems which fit the overall plan of operation. These excavations
RhinoOne Geotechnical 14610 NE 77th Avenue#126 I Vancouver,WA 98662 I phone 360.258.1738
December 16,2016
Project DBG-2016-003
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Geotechnical Investigation Report Fields Apartments
Tigard,Oregon
should be made in accordance with applicable Occupational Safety and Health Administration and
State regulations.
5.0 CONSTRUCTION OBSERVATIONS
Satisfactory earthwork performance depends on the quality of construction. Sufficient observation of
the contractor's activities is a key part of determining if the work is completed in accordance with the
construction drawings and specifications. We recommend a geotechnical engineer from ROG be
retained to observe geotechnical related construction efforts.
Subsurface conditions observed during construction should be compared with those encountered
during the subsurface explorations discussed above. Recognition of changed conditions requires
experience. Therefore, qualified personnel should visit the site with sufficient frequency in order to
detect whether subsurface conditions have changed significantly from those anticipated.
6.0 LIMITATIONS
This report has been prepared for the exclusive use of the addressee and engineers, and for aiding
in the design and construction of the proposed project. It is the addressee's responsibility to provide
this report to the appropriate design professionals, building officials, and contractors to ensure
correct implementation of the recommendations.
The opinions, comments, and conclusions presented in this report were based upon information
derived from our literature review, field investigation, and laboratory testing. Conditions between or
beyond our exploratory borings may vary from those encountered. Unanticipated soil conditions and
seasonal soil moisture variations are commonly encountered and cannot be fully determined by
merely taking soil samples or soil borings. Such variations may result in changes to our
recommendations and may require additional expenditures be made to attain a properly
constructed project. Therefore, some contingency fund is recommended to accommodate such
potential extra costs.
If there is a substantial lapse of time between the submission of this report and the start of work at
the site, if conditions have changed due to natural causes or construction operations at or adjacent
to the site, or if the basic project scheme is significantly modified from that assumed, it is
recommended this report be reviewed to determine the applicability of the conclusions and
recommendations.
RhinoOne Geotechnical 14610 NE 77th Avenue#126 I Vancouver,WA 98662 I phone 360.258.1738
December 16,2016
Project DBG-2016-003
14
Geotechnical Investigation Report Fields Apartments
Tigard,Oregon
7.0 RESTRICTIONS
This report is for the exclusive use of the client for design of the development, as described in our
proposal for this particular project, and is not to be relied upon by other parties. It is not to be
photographed, photocopied, or similarly reproduced, in total or in part, without the expressed written
consent of the client and ROG.
Sincerely,
RhinoOne Geotechnical
Christina Hemberry, PE
Staff Geotechnical Engineer
Rajiv Ali, PE GE (OR)
Principal Geotechnical Engineer
RhinoOne Geotechnical 14610 NE 77th Avenue#126 I Vancouver,WA 98662 I phone 360.258.1738
December 16,2016
Project DBG-2016-003
15
APPENDIX A
Site Location Map
Site Exploration Plan
• Rh�nO�ne -, Fields Apartments
, gilts SW Hunziker Street and SW Wall Street
8_0 ECHNICA[ ' Tigard,Oregon
Boring Number:
Project:Fields Apartments Driller:Dan J Fischer Excavating,Inc.
Proj No.:DBG-2016-003 Date:November 17,2016 B-3
Drilling Method:Solid-Stem Auger Elevation:Approximately 197 feet AMSL
Diameter:4.25-inch auger Water Table:8 feet Logged by:Christina H
z in
o a S a y a� o
Z
aa)i [j 5 S F t ,..
�. Materials Description B Remarks
g N
A o ° o t a P
0
':'
. TP _ Brown,fine sandy SILT;moist(8-inch Root Zone)
-
— ML Medium stiff,brown,SILT with trace fine sand and
- clay;damp,medium plasticity
y 1 56 1-3-4 7 30.7
0 5
2 \ 50 2-2-5 7 - 33.4
b
0
Z - •':: SM Loose,brown,silty fine SAND;wet,low to no
3 \ 56 2-2-3 5 plasticity 29.6
w 10-.:::::d
, 4 \ 68 2-1-2 3 33.6
CS .1.,
go
,.:. Becomes very loose,silty fine to medium SAND
°x
I5 \ 72 1-1-2 3 .`. 32.7
C
;=.."ii -
20—.:•
A 6 \ 88 1-1-2 3 - 34.7
3 J \...,:ti
3
r Becomes loose and blue-grey
7 78 2-1-6 7 33.2
TI:
30 ML Soft to medium stiff,blue-grey,fine sandy SILT;
8 88 2-2-2 4 moist,medium plasticity 35.7
'. N
Page 3
RhinoOne Fields Apartments
SW Hunziker Street and SW Wall Street
G E 1 E D-N C A L Tigard,Oregon
Boring Number:
Project:Fields Apartments Driller:Dan J Fischer Excavating,Inc.
Proj No.:DBG-2016-003 Date:November 17,2016 B-3
Drilling Method:Solid-Stem Auger Elevation:Approximately 197 feet AMSL
Diameter:4.25-inch auger Water Table:8 feet Logged by:Christina H
z in
T G S y p "�
00
6 ' g O _h
0 N 0 s U .5 V Materials Description Remarks
2.
8 a o ° 0 c'
35 %/f CH-MH Stiff to very stiff,blue-grey,clayey SILT;moist,
9 \ 72 4-6-9 15 medium to high plasticity 24.8
ry
40 CH Stiff,blue-grey,CLAY;moist,high plasticity
10 72 3-6-7 13 38.8
Boring terminated at 41.5(feet BGS):boring
backfilled with bentonite chips and capped with
native soil
b
45—
M
e
N —
V
2
W _
50—
� I _
Ci
55—
3 � _
60—
o '
65—
I
i II _ II
Page 4
��r��®�� , , Fields Apartments
_ 1'. SW Hunziker Street and SW Wall Street
O—E C H N { 4', Tigard,Oregon
Boring Number:
Project:Fields Apartments Driller:Dan J Fischer Excavating,Inc.
Proj No.:DBG-2016-003 Date:November 17,2016 B-7
Drilling Method:Solid-Stem Auger Elevation:Approximately 187 feet AMSL
Diameter:4.25-inch auger Water Table:9.5 feet Logged by:Christina H
z
6 E›+cl. S C p pa o b�
0 °: s C.) .fLI Materials Description Remarks
§ o o 0 0 a V
cn g4 P4 14 a. CA Q C7
0 Brown,fine sandy SILT;moist(6-inch Root Zone)
ML l
Very stiff,brown,SILT with some fine sand;damp
to moist,low to medium plasticity
h 1 66 5-8-8 16 18.2
N
o 5 Becomes medium stiff,fine sandy SILT
2 44 2-2-3 5 25.8
to
go
Becomes stiff
a 3 \ 78 3-3-8 11 25.2
10 Becomes medium stiff
• 4 \ 62 3-3-4 7 31.0
6
0
NL
V
2
U
15 Becomes brown with grey mottling
s 5 \ 62 2-3-4 7 29.8
w
S
I
20 -
/// CL-ML Soft,blue-grey,clayey SILT with some fine sand;
• 6 \ 50 2-2-2 4 / moist,medium plasticity 34.4
3 ,
25 cL Stiff,blue-grey,CLAY;moist,medium plasticity
ti 7 100 3-4-6 10 % 32.6 LL=40.3%
PL=22.8%
S PI= 17.5%
y �
30
8 \ 100 3-6-12 18 Becomes very stiff
26.1
4 n,
Page 5
RhinoOne Fields Apartments
alta` SW Hunziker Street and SW Wall Street
GEO-ECHNICA_ Tigard,Oregon
Boring Number:
Project:Fields Apartments Driller:Dan J Fischer Excavating,Inc.
Proj No.:DBG-2016-003 Date:November 17,2016 B-7
Drilling Method:Solid-Stem Auger Elevation:Approximately 187 feet AMSL
Diameter:4.25-inch auger Water Table:9.5 feet Logged by:Christina H
z
o a' 6' s Z pq o
z H so H
vMaterials Description Y Remarks
E 8 a o o a f
C4 u; Gq a at 3 Q C7
35 ML Stiff,brown,fine sandy SILT;damp,medium
9 \ 78 3-5-5 10 plasticity 38.5
N -
Loose to medium dense,brown,silty fine to coarse
10 \ 62 3-5-5 10 SAND;moist 36.5
Boring terminated at 41.5(feet BGS):boring
backfilled with bentonite chips and capped with
e –
native soil
45—
o
0
e
.N
V
U
`-V
°� 50—
o
I ! I
c.s
55
3 I
`c
3
60—
h
ci
y
65—
II –
Page 6
RRN
nmoOne fi=t Fields Apartments
�[ l SW Hunziker Street and SW Wall Street
• GEO-ECHNICAL Tigard,Oregon
Boring Number:
Project:Fields Apartments Driller:Dan J Fischer Excavating,Inc.
Proj No.:DBG-2016-003 Date:November 17,2016 TP-I
Drilling Method:Test Pit Elevation:Approximately 202 feet AMSL
Diameter:24 inch bucket Water Table:NA Logged by:Christina H
z in
6 a o °' pa o
o a
s v H v Materials Description Remarks
° o Q 3 ‹0 3 ? '5 o
r24 GQ a P1 C7
0 < <
Dark brown,sandy SILT;moist(8-inch Root Zone)
CL-ML Red brown,clayey SILT;moist,medium plasticity
s
C
2 j
0 3 /
ry
X32.0 LL=36.0%
PL=25.5%
/ PI= 10.8%
4
ML Light brown,fine sandy SILT;damp,low plasticity
6
`i
E V
2 27.2
s I
8
•3 I —
a I I
Test Pit terminated at 9.5(feet BGS):Test pit
10— backfilled with excavated material and lightly
tamped in place
4 - I
12—
I I
Page 1
e 1
Fields Apartments 4,
RhinoOne , i&$ SW Hunziker Street and SW Wall Street
G E O-E C H N L C A Tigard,Oregon
Boring Number:
Project:Fields Apartments Driller:Dan J Fischer Excavating,Inc.
Proj No.:DBG-2016-003 Date:November 17,2016 TP-2
Drilling Method:Test Pit Elevation:Approximately 204 feet AMSL
Diameter:24 inch bucket Water Table:9.5 feet Logged by:Christina H
z
a - So o pa o
0 ,u v. s U . F" 2 Materials Description Remarks
a
cn x a4 as a, as 3 A 0
0 , „
<'<'<' Te Dark brown,sandy SILT;moist(6-inch Root Zone)
} ML Light brown,SILT with trace fine sand;moist,
medium plasticity
b
O
h
2
N
I
Q
j0
Z
ti.
4.
4
1 X 34.5
N
(.
Becomes SILT with some fine sand
w
6 —
o
a � i
C.i
-.
o
8
2 X
3
3
3
y 1 _ . SM Brown,silty fine SAND;moist,low to no plasticity
a =
3 { 29.7 Seepage observed
10 at 9.5 feet
U
_ Test Pit terminated at 10.6(feet BGS): Test pit
backfilled with excavated material and lightly
tamped in place
12—
I
Page 2
khal dnOOne ��, Q Fields Apartments
o. 1 SW Hunziker Street and SW Wall Street
• G E OT E C H N I CA_ Tigard,Oregon
Boring Number:
Project:Fields Apartments Driller:Dan J Fischer Excavating,Inc.
Proj No.:DBG-2016-003 Date:November 17,2016 TP-4
Drilling Method:Test Pit Elevation:Approximately 218 feet AMSL
Diameter:24 inch bucket Water Table:NA Logged by:Christina H
ztip
d F S 6 o 2 o S
o „ 0 . F" - Materials Description Remarks
ain x w a. ca 3 A a" 2
0 `,,.<, TP Dark brown,sandy SILT;moist to wet,low
–4>4Y plasticity(8-inch Root Zone)
a - ML Brown,fine sandy SILT;moist,medium plasticity
0
G
N
O
C
b
n 2 —
N
Q -
s
m.a
s 1 X 4 28.8 LL=33.0%
M PL=27.3%
0
PI=5.7%
N
V
2 _ Becomes SILT with some fine to medium sand,
w damp
a
t 6
o
t
Ci
,V
82 X26.4
.r
A
3
3
3
Q
a I
4
– Test Pit terminated at 9.5(feet BGS): Test pit
y 10— backfilled with excavated material and lightly
g – tamped in place
U
s
4
12—
Page 5
``� Fields Apartments
RhinoOne
i13, SW Hunziker Street and SW Wall Street .
GEOTECHNICA_ Tigard,Oregon
Boring Number:
Project:Fields Apartments Driller:Dan J Fischer Excavating,Inc.
Proj No.:DBG-2016-003 Date:November 17,2016 TP-5
Drilling Method:Test Pit Elevation:Approximately 213 feet AMSL
Diameter:24 inch bucket Water Table:NA Logged by:Christina H
z
SoT °
co
o r' o
Z H UO O wv u U Materials Description a
,04 Remarks
'0,0 °$ 0 al `
6. o
cn cn x x as & PI 3 A u'
0 < .
s'.'<' TP Dark brown,sandy SILT;moist(6-inch Root Zone)
} .
',3- > ML Light brown,SILT with some fine to medium sand;
moist,low to medium plasticity
U
8
O
b
O
h 2
ti
Q
1 I • — 25.3
I
434
Q I
4 a ` SM Brown,silty fine SAND;moist
o
2
r ";a
0
m
4 6 ML Light brown,fine sandy SILT;damp,low to
- medium plasticity
o
a
8 —,
1
3 I
c
1
I — Test Pit terminated at 9.5(feet BGS): Test pit
10— backfilled with excavated material and lightly
s
ti _ tamped in place
U —
to
0
i
12
I
— '' III
I I
— I
Page 6
qP F I
tnmoOne * Fields Apartments
. � Ip,Y SW Hunziker Street and SW Wall Street
• GEOTECt i ICA_ , ' Tigard,Oregon
Boring Number:
Project:Fields Apartments Driller:Dan J Fischer Excavating,Inc.
Proj No.:DBG-2016-003 Date:November 17,2016 TP-6
Drilling Method:Test Pit Elevation:Approximately 207 feet AMSL
Diameter:24 inch bucket Water Table:NA Logged by:Christina H
z cii
oh C v o o
e
0 = .a s .)0 N ,3;) c .5 Materials Description =
Remarks
a. o
Oca g a8i ' o �o 0 io c 'o
c4 v) a PA o. 04 Q c7
0 <'<'<' Ti' Dark brown,sandy SILT;moist(6-inch Root Zone)
ML Brown,fine sandy SILT;moist to wet,low to no
0
plasticity
0
1 X22.2
H 0 2 —
N
oto
.
ti
s I
4 1
o
e
0
N –
V
0
U
43O
t6 Becomes damp
t.
_ /
Ci
c
S
0
8 —
tt
3
j
3 Test Pit terminated at 9.5(feet BGS): Test pit
10— backfilled with excavated material and lightly
E..., _ tamped in place
s,
12—
Page 7
0
APPENDIX B
Summary Boring Logs
Laboratory Testing
4.0
RhinoOne
C_3 E-C J f F-t,H N 1 F A;....
Project Name: Fields Apartments Tested By: RA
Project Number: DBG-2016-003 Laboratory No: 2016-00005
Date 20-Nov-16
OVEN DRY MOISTURE CONTENT- ASTM D 2216
Sample ID: B-3 B-3 B-3 B-3 B-3 B-3 B-3 B-3 B-3 B-3
Depth: 2.5-4 5-6.5 7.5-9 10-11.5 15-16.5 20-21.5 25-26.5 30-31.5 35-36.5 40-41.5
Tare Number: 001 002 013 003 004 014 015 016 017 026
Weight of Tare (Wt.): 51.25 51.58 50.26 51.25 50.6 51.22 51.55 51.66 51.69 51.42
Weight of Tare+Wet Soil: 161.17 163.44 165.55 168.17 185.4 178.68 172.58 146.33 177.63 146.11
Weight of Tare+ Dry Soil: 135.36 135.44 139.22 138.78 152.2 145.85 142.4 121.44 152.64 119.66
Weight of Dry Soil: 84.11 83.86 88.96 87.53 101.6 94.63 90.85 69.78 100.95 68.24
Weight of water: 25.81 28 26.33 29.39 33.2 32.83 30.18 24.89 24.99 26.45
Water Content(%): 30.7% 33.4% 29.6% 33.6% 32.7% 34.7% 33.2% 35.7% 24.8% 38.8%
Soil Description:
IR9{� tnoOne
EC) f :;I I JIC w
Project Name: Fields Apartments Tested By: RA
Project Number: DBG-2016-003 Laboratory No: 2016-00005
Date 20-Nov-16
OVEN DRY MOISTURE CONTENT- ASTM D 2216
Sample ID: B-7 B-7 B-7 B-7 B-7 B-7 B-7 B-7 B-7 B-7
Depth: 2.5-4 5-6.5 7.5-9 10-11.5 15-16.5 20-21.5 25-26.5 30-31.5 35-36.5 40-41.5
Tare Number: 005 018 006 007 008 019 020 021 022 023
Weight of Tare (Wt.): 51.72 51.58 51.12 51.56 51.82 51.37 51.76 51.01 51.79 51.7
Weight of Tare+Wet Soil: 186.92 152.27 169.3 178.82 167.6 167.81 170.03 172.59 145.24 161.59
Weight of Tare+ Dry Soil: 166.11 131.63 145.5 148.68 141.04 138.02 140.93 147.44 119.26 132.19
Weight of Dry Soil: 114.39 80.05 94.38 97.12 89.22 86.65 89.17 96.43 67.47 80.49
Weight of water: 20.81 20.64 23.8 30.14 26.56 29.79 29.1 25.15 25.98 29.4
Water Content (%): 18.2% 25.8% 25.2% 31.0% 29.8% 34.4% 32.6% 26.1% 38.5% 36.5%
Soil Description:
4
Rnoone
GPO.I_.['ICH N1(_:; L
Project Name: Fields Apartments Tested By: RA
Project Number: DBG-2016-003 Laboratory No: 2016-00005
Date 20-Nov-16
OVEN DRY MOISTURE CONTENT- ASTM D 2216
Sample ID: TP-1 TP-1. TP-2 TP-2 TP-4 TP-4 TP-5 TP-6
Depth: 2.5-3.5 7-7.5 4-5 9.5-10 3.5-4 8-8.5 2.5-3 1.5-2
Tare Number: 027 009 011 028 029 030 031 032
Weight of Tare (Wt.): 51.54 51.49 51.61 51.48 51.8 51.68 51.68 51.45
Weight of Tare+Wet Soil: 160.16 160.2 179.4 168.66 173.27 157.94 175.29 190.1
Weight of Tare+ Dry Soil: 133.82 136.98 146.61 141.8 146.08 135.76 150.35 164.88
Weight of Dry Soil: 82.28 85.49 95 90.32 94.28 84.08 98.67 113.43
Weight of water: 26.34 23.22 32.79 26.86 27.19 22.18 24.94 25.22
Water Content (%): 32.0% 27.2% 34.5% 29.7% 28.8% 26.4% 25.3% 22.2%
Soil Description:
Atterberg Limits (ASTM D4318,AASHTO 189/90)
Project Name: Willow Creek&Fields Apartments Project No.: DBG-2016-002&3 1658
Exploration Number: Fields B-7 Sample No.: Depth: 25.0-26.5
Date: 12/14/2016 Tested By: MTR Checked by: USCS Symbol
Description of Soil: Medium Brown Clay CL
Natural Moisture Can# Wt.of wet Wt of dry soil Wt.of can Moisture Wt.of dry Moisture
Content soil and can(g) and can(g) (g) loss(g) soil(g) Content(%)
1555.50 1352.50 658.70 203.00 693.80 29.3
Liquid Limit Test . ; , _ T - w e ., 2 3. 5 ,, 4 . . . 5
Container Number 6 20 19
Number of Blows 34 23 16
Wt.of wet soil and can(g) 34.93 34.5 33.45
Wt.of dry soil and can(g) 31.28 30.59 29.79
Wt.of can(g) 21.42 21.08 21.40
Moisture loss(g) 3.65 3.91 3.66
Wt.of dry Soil(g) 9.86 9.51 8.39
Moisture Content% 37.0 41.1 43.6
Plastic Limit Test 1 2
Container Number 18 17 Calculation
Wt.of wet soil and can(g) 24.56 24.59 Liquid Limit 40.3
Wt.of dry soil and can(g) 23.94 23.99 Plastic Limit 22.8
Wt.of can(g) 21.28 21.30 Plasticity Index 17.5
Moisture loss(g) 0.62 0.60
Wt.of dry soil(g) 2.66 2.69
Moisture Content% 23.3 22.3
l
Liquid Limit Determination Plasticity Chart
60 :
90 :.. ._.._. _._._ _.._ :..._.:: z i CH
80 _. :: 50 ! ( 1i
0 7Q v.� ..... ...... _ =40 CL ` i I
60 .. d 1
c x
0 50 _ _ _._. �: c 30 t
u i
II' L
N l
2 30 20
MH&OH
20i
10
10 n Mi ! ML&OL
Q .._. .... .. _. Q :..._ _ --
10 20 25 30 40 50 0 10 20 30 40 50 60 70 80 90 100
No.of Blows Liquid Limit,LL(%)
K.
Atterberg Limits (ASTM D4318,AASHTO T89/90)
Project Name: Willow Creek&Fields Apartments Project No.: DBG-2016-002&3 1658
Exploration Number: Fields TP-1 Sample No.: Depth: 2.5-3.0
Date: 12/14/2016 Tested By: MTR Checked by: USCS Symbol
Description of Soil: Medium Brown Clayey Silt ML& OL
Natural Moisture Can 5 Wt.of wet Wt.of dry soil Wt.of can Moisture Wt.of dry Moisture
Content soil and can(g) and can(g) (g) loss
(g) soil(g) Content(%)
1283.30 1157.30 742.70 126.00 414.60 30.4
Liquid Limit Test 1 2 3 4 - 1 5 `
Container Number 23 22 5
Number of Blows 17 24 33
Wt.of wet soil and can(g) 34.46 36.65 36.68
Wt.of dry soil and can(g) 30.93 32.76 32.70
Wt.of can(g) 21.39 21.45 21.83
Moisture loss(g) 3.53 3.89 3.98
Wt.of dry Soil(g) 9.54 11.31 10.87
Moisture Content% 37.0 34.4 36.6
Plastic Limit Test 1, 2
Container Number 1 21 Calcu n
Wt.of wet soil and can36.0
(g) 28.58 28.27 Liquid Limit
Wt. dryof soil and can252
(g) 27.04 26.87 Plastic Limit
Wt.of can(g) 20.95 21.30 Plasticity Index 10.8
Moisture loss(g) 1.54 1.40
Wt.of dry soil(g) 6.09 5.57
Moisture Content% 25.3 25.1
Liquid Limit Determination Plasticity Chart
' i ! CH
,
50
80
.. _ :. ...... CL
70
40 , i
6o 0.
50o __.. 'c 30 ' :
- - ; : • '
N 40
E 30 A 20
_::: a
20 _.... ___.. ...... i MC&OX
: v
10 n-m� ML;&OL
10 20 25 30 40 50 0 10 20 30 40 50 60 70 80 90 100
No.of Blows Liquid Limit,LL(%)
Atterberg Limits (ASTM D4318,AASHTO T89/90)
Project Name: Willow Creek&Fields Apartments Project No.: DBG-2016-002&3 1658
Exploration Number: Fields TP-4 Sample No.: Depth: 3.5-4.0
Date: 12/9/2016 Tested By: MTR Checked by: USCS Symbol
Description of Soil: Medium Brown Silt ML &OL
Natural Moisture Can# Wt.of wet Wt.of dry soil Wt.of can Moisture Wt.of dry Moisture
Content soil and can(g) and can(g) (g) loss(g) soil(g) Content(%)
1220.70 1055.40 461.70 165.30 593.70 27.8
Liquid Limit Test - . 1 ‘-. - -,,..' 2 .- . ..'..- I',:3 ,'-:-. - -;. 4 , ,\.S ''','"'. ''',;:-''5'.'•••:- -n,,
Container Number 8 13 2
25 17 34
Number of Blows
38.55 35.00 35.72
Wt.of wet soil and can(g)
34.31 31.41 32.23
Wt.of dry soil and can(g)
21.46 21.24 20.79
Wt.of can(g)
4.24 3.59 349
Moisture loss(g)
1285 10.17 11.44
Wt.of dry Soil(g)
33.0 35.3 30.5
Moisture Content%
Plastic Limit Test 1 , ,. - 2 ,.,.
.:
14 4
Container Number ". ' '..'S''' ' Calculation .'. - ,..::-7'.'...-•'.'':k7::4'.'
28.70 28.65 33.0
Wt.of wet soil and can(g) Liquid Limit
27.05 27.11 27.3
Wt.of dry soil and can(g) Plastic Limit
21.52 5.7
Wt.of can(g) 20.96Plasticity Index
1.65 1.54
Moisture loss(g)
6.09 5.59
Wt.of dry soil(g)
27.1 27.5
Moisture Content%
Liquid Limit Determination Plasticity Chart
100 60 , . ;
. : . 1 : • .
: i i , i : I . . • .
.....
• i . 1 i i .
-'L' i - • .1 20 • ' ' ' ' ' ' ' ' '. ;
1.0
0 10
20 25 30 40 50 0 10 20 30 40 50 60 70 80 90 100
No.of Blows liquid Limit,LL(%)