basis of design report | 60% appendix 7

Basis Of Design Report | 60% Appendix 7.6

December 2020

North Fork Touchet Habitat Restoration | River Mile 1.7 – 2.6

Appendix 7.6 – Geotechnical Report

GEOTECHNICAL ENGINEERING REPORT North Fork Touchet River Bridge Replacement Prepared for: Inter-Fluve, Inc.

Project No. 200313 September 18, 2020 DRAFT

GEOTECHNICAL ENGINEERING REPORT North Fork Touchet River Bridge Replacement Prepared for: Inter-Fluve, Inc.

Project No. 200313 September 18, 2020 DRAFT

Aspect Consulting, LLC

Andrew J. Holmson, PE Associate Geotechnical Engineer [email protected]

Jasmin S. Toro, EIT Staff Engineer [email protected]

V:\200313 N. Fork Toughet Bridge\Deliverables\Geotechnical Engineering Report\Draft\NF Touchet Bridge Replacement DRAFT_09.16.2020.docx

PRELIMINARY

e a r t h + w a t e r Aspect Consulting, LLC 522 SW Fifth Avenue, Suite 1300 Portlan d, OR 97204 971.865.5890 www.aspectconsulting.com

PROJECT NO. 200313 SEPTEMBER 18, 2020 DRAFT i

Contents

List of Appendices .............................................................................................. ii

1 Introduction ................................................................................................. 1 1.1 Project Description ..................................................................................... 1

2 Site Conditions ............................................................................................ 2 2.1 Surface Conditions ..................................................................................... 2 2.2 General Geology ........................................................................................ 2 2.3 Subsurface Conditions ............................................................................... 2

2.3.1 Subsurface Explorations ....................................................................... 3 2.3.2 Laboratory Testing ................................................................................ 3 2.3.3 Stratigraphy .......................................................................................... 3 2.3.4 Groundwater ......................................................................................... 4

3 Conclusions and Recommendations......................................................... 5 3.1 Seismic Design Considerations .................................................................. 6

3.1.1 Ground Response................................................................................. 6 3.1.2 Surficial Ground Rupture ...................................................................... 6 3.1.3 Liquefaction .......................................................................................... 7

3.2 Engineering Properties ............................................................................... 7 3.3 Bridge Foundations .................................................................................... 8

3.3.1 Spread Footings ................................................................................... 8 3.3.2 Driven Piles .......................................................................................... 9

3.4 Abutment Design ...................................................................................... 11 3.4.1 Lateral Earth Pressures ...................................................................... 11 3.4.2 Sliding Resistance .............................................................................. 12 3.4.3 Drainage ............................................................................................. 12

3.5 Global Stability.......................................................................................... 13 3.6 Steel Sheet Piles ...................................................................................... 13

4 Construction Considerations ................................................................... 14 4.1 Driven Pile Installation .............................................................................. 14

4.1.1 Geotechnical Monitoring of Driven Piles ............................................. 14 4.1.2 Site Subsurface Variation and Pile Lengths ........................................ 14

4.2 Earthwork ................................................................................................. 15 4.2.1 Temporary Excavation Slopes and Temporary Shoring ...................... 15 4.2.2 Construction Dewatering..................................................................... 16 4.2.3 Subgrade Preparation ......................................................................... 16 4.2.4 Structural Fill ....................................................................................... 17

5 Recommendations for Continuing Geotechnical Services .................... 19 5.1 Additional Design and Consultation Services ........................................... 19

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ii DRAFT PROJECT NO. 200313 SEPTEMBER 18, 2020

5.2 Additional Construction Services .............................................................. 19

6 References ................................................................................................. 20

7 Limitations .................................................................................................. 21

List of Tables 1 Seismic Design Parameters .......................................................................6

2 Soil Engineering Properties ........................................................................7

3 LRFD Resistance Factors for Spread Footings ..........................................9

4 Resistance Factors for Driven Pile Design ............................................... 10

5 Lateral Earth Pressure Parameters .......................................................... 12

6 Recommended Soil Properties for Temporary Shoring Design ................ 16

List of Figures 1 Site Location Map

2 Site and Exploration Plan

3 Footing Bearing Resistance

4 HP14x89 Driven H-Pile Axial Resistance at Southwest Abutment

5 HP14x89 Driven H-Pile Axial Resistance at Northeast Abutment

List of Appendices A Subsurface Explorations

B Laboratory Testing Results

C Liquefaction Analysis Results

D Report Limitations and Guidelines for Use

PROJECT NO. 200313 SEPTEMBER 18, 2020 DRAFT 1

1 Introduction This report presents the results of Aspect Consulting, LLC’s (Aspect) geotechnical engineering investigation supporting the North Fork Touchet River Bridge Replacement (Project) at Vernon Lane southeast of Dayton, Washington (Site). This report summarizes the results of completed field explorations and presents Aspect’s geotechnical engineering conclusions and recommendations for the Project.

1.1 Project Description The greater project includes restoration of the Touchet River and floodplain in the vicinity of Vernon Lane. A key component of the restoration is the replacement of an existing, privately owned and maintained, single-span bridge that currently provides the primary trucking egress for an orchard along the left bank of the Touchet River. The existing bridge is approximately 80 feet long and the proposed bridge will be a significantly longer (approximately 150 feet), 16-foot-wide, single-span truss structure with a concrete deck slab.

As part of the greater project, the floodplain below the replacement bridge will be excavated along the left bank of the river to widen the activated floodplain and remove fill associated with the existing levee and bridge abutment. A new, setback levee will be constructed and coincide with the proposed southwest bridge abutment location. The right bank of the river and an existing rock revetment will not be altered as part of the Project other than what is required for removing the existing bridge abutment. Grading of the floodplain will be focused along the left bank of the river and include removal of existing fill associated with the current bridge approach and flattening of the floodplain. A new river channel side slope inclined at 3H:1V (Horizontal:Vertical) is proposed from the floodplain to the new bridge abutment and approach. The bridge approaches will not be significantly altered and mostly match existing grades with less than 2 feet of fill required; therefore, no wing walls are anticipated for the proposed bridge.

The design of the replacement bridge structure will be completed by the bridge manufacturer and will be in general accordance with Washington State Department of Transportation (WSDOT) and American Association of State Highway and Transportation Officials (AASHTO) Bridge Design Specifications (BDS) criteria.

Aspect’s scope of work for the Project includes reviewing existing geologic data; completing subsurface investigations at the Site to observe and document soil conditions near the bridge; and providing geotechnical engineering analysis to develop design criteria for the bridge foundations and other geotechnical components of the Project.

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2 DRAFT PROJECT NO. 200313 SEPTEMBER 18, 2020

2 Site Conditions This section presents the Site conditions, including Site surface conditions, geologic setting, and subsurface conditions. This information provides context for the discussion of types and distribution of geologic soil units and a basis for our geotechnical engineering recommendations.

2.1 Surface Conditions The Site is located at the intersection between the North Fork Touchet River and Vernon Lane. The existing bridge is a two-span, one-lane, timber deck bridge with steel girders and concrete footings located at either abutment and at mid-span in the river. The bridge deck is about 12 feet wide, at about Elevation 1815, and the bridge spans about 80 feet across the river.

The North Fork Touchet river channel is about 10 feet below the bridge deck with channel slopes that are between 1.5H:1V and 1H:1V. The northeast side of the river is lined by a large riprap revetment. An existing levee, that is about 5 to 6 feet tall, is present along the southwest side of the river.

Riparian vegetation exists along the banks of the river and includes moderate shrubbery, short grasses, and scattered mature trees above the floodplain. Southwest of the Site and river is a production orchard and northeast of the Site and river are irrigated and non-irrigated fields.

The existing Site topography and select features are shown on Figure 2, Site Exploration Plan.

2.2 General Geology The available geologic mapping (DNR, 2020) indicates the Site is underlain by recent coarse-grained (high gravel and cobble content) Quaternary Alluvium (Qal) deposits of sand and gravel with limited silt and clay. The deposits are largely confined to streambeds and fans with varied thickness and sorting and commonly include reworked loess and outburst flood deposits. Underlying the alluvium at the Site are the Columbia River Basalt Group’s (CRBG) Miocene-aged Grande Ronde Basalt (Mv). The Grand Ronde Basalt is described as Miocene-aged, blue-black, dense, and finely crystalline rock that weathers light brown to yellowish brown. Locally, the basalt can be weathered and mantled by reddish brown residual soil that has been formed by the decomposition of the basalt into rock fragments suspended in a silt and clay matrix.

From the results of our explorations and field observations, the soils near the ground surface at the Site are composed of Quaternary Alluvium. The alluvium consists primarily of gravel with various amounts of silt, sand, cobbles, and boulders.

2.3 Subsurface Conditions The subsurface conditions at the Site were characterized through our review of the available geologic mapping, our reconnaissance of the Site, and the results of the subsurface explorations and lab testing.


2.3.1 Subsurface Explorations We explored the subsurface conditions at the Site by overseeing the drilling of two borings (AB-01 and AB-02) on August 20 and August 21 to depths of 37 and 51.2 feet below ground surface (bgs), respectively. The location of our exploration is shown on Figure 2. Details of exploration methods, and exploration logs are presented in Appendix A.

Soils were described per the Unified Soil Classification System (USCS) in general accordance with the ASTM International (ASTM) Method D2488 Standard Practice of Description and Identification of Soils (ASTM, 2020). A key to the symbols and terms used on the logs is provided on the Exploration Log Key. The depths on the logs where conditions changed may represent gradational variations between soil types, and actual transitions may be more gradual.

Selected soil samples obtained from the boring were submitted for geotechnical laboratory testing to characterize index and engineering properties. Geotechnical laboratory test results are included in Appendix B.

2.3.2 Laboratory Testing Laboratory tests were conducted on selected soil samples to characterize certain engineering (physical) properties of the soils at the Site. Laboratory testing included determination of fines content and grain-size distribution. The laboratory tests were conducted in general accordance with appropriate ASTM International (ASTM) test methods. Test procedures are discussed in more detail in Appendix B of this report.

2.3.3 Stratigraphy From our review of Site surface and subsurface conditions, the primary near-surface geologic unit is Quaternary Alluvium, which underlies the existing roadway and bridge abutments on both the SW (AB-01) and NE (AB-02) sides of the river. We also encountered Fill above the alluvium at AB-01. The three principal engineering/geologic units encountered in our Site explorations, from ground surface down, are fill, alluvium, and basalt.

Fill We encountered fill beneath the roadway gravel base in exploration AB-01, located on the SW side of the Touchet River and coinciding with the existing levee alignment. We inferred the fill was associated with elevating the existing levee above the adjacent floodplain. The fill extended from the ground surface to a depth of approximately 7.5 feet below ground surface (bgs) and primarily consisted of medium dense, slightly moist to moist, brown to red brown, GRAVEL with sand (GW) 1; fine to coarse sand; fine to coarse, subrounded to subangular gravel.

The fill exhibits moderate shear strength characteristics, low compressibility, moderate to high permeability, and low moisture sensitivity characteristics due to the lack of fines (soil particles pass the No. 200 sieve).

1 Soils classified in accordance with the Unified Soil Classification System (USCS), ASTM D2488.

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Alluvium We encountered alluvium deposits beneath the fill in AB-01 and beneath the roadway gravel base in AB-02. The alluvium extended to depths ranging from 37 feet bgs at AB-01 to 34 feet bgs at AB-02. The alluvium typically consisted of medium dense to very dense, moist, brown, gray brown and dark gray, GRAVEL (GW-GM, GW) with varying amounts of silt, sand, cobbles and boulders. Layers of SAND (SM, SP-SM, SP) with varying amounts of silt and gravel were also intermittently encountered within the alluvium. Trace and subtrace woody organics were encountered as deep as 15 feet bgs, scattered cobbles and boulders were interpreted to be present throughout the alluvium based on visual observations of surficial alluvium and based on difficult drilling conditions.

The alluvium exhibits moderate to high shear strength characteristics, low compressibility, moderate to high permeability, and low moisture sensitivity characteristics due to the lack of fines (soil particles pass the No. 200 sieve).

Basalt Weathered basalt was encountered at depths of approximately 34 to 35 feet bgs in both borings and extended to the bottom of the borings. The basalt was observed to be extremely weak to medium strong, dark gray, and varied from residual soil to moderately weathered rock. The weathered basalt varied in grain size and is classified as silty SAND (SM), and GRAVEL (GP) with varying amounts of silt, sand, cobbles and boulders.

The weathered basalt exhibits high shear strength characteristics, low compressibility, moderate to high permeability, and moderate moisture sensitivity characteristics due to limited fines (soil particles pass the No. 200 sieve).

2.3.4 Groundwater At the time of our explorations on August 20 and 21, 2020, due to drilling using circulated bentonite (mud rotary methods), we were not able to directly measure the groundwater levels in the borings. However, based on the Site topography, the highly permeable subsurface conditions, and our field observations of the water levels in the river, the groundwater within the Project area can be expected to be in hydraulic continuity with the river and will typically fluctuate with and mirror the river water levels.

Groundwater levels will vary based on precipitation patterns, local irrigation patterns, and Site/near Site usage.


3 Conclusions and Recommendations The replacement bridge may be supported on driven pile foundations or spread footing foundations. We anticipate that factors including cost, limiting the footprint of significant scour protection required within the restored river channel, and constructability will impact which type of bridge foundations are ultimately used for the Project. Accordingly, the report provides design recommendations for both spread footings and driven piles. A summary of key Project geotechnical conclusions and recommendations are listed below and described in more detail in the following sections.

• The granular, dense alluvium deposits underlying the areas of the proposed bridge abutments are not susceptible to liquefaction during the AASHTO design earthquake and will provide suitable bearing support for spread footing bridge foundations with relatively low settlement potential.

• Similarly, the alluvium deposits and weathered basalt bedrock at depth will provide suitable support for driven pile bridge foundations.

• If spread footings are used to support the new bridge, they should be founded below the design scour level (determined by Inter-Fluve) and/or protected by appropriate scour protection measures.

• Spread footings should be constructed directly atop a 12-inch-thick fill pad consisting of compacted crushed rock overlying the existing granular alluvium. The crushed rock fill pad is intended to provide relatively uniform support directly beneath the foundations that will be constructed over subgrade soils that are expected to contain variable amounts of cobble and boulders.

• Driven piles should consist of relatively stout, steel H-piles equipped with steel drive points to protect the pile from damage when driving through the relatively coarse, gravelly and cobbly alluvium and to refusal on the basalt bedrock.

• Driven steel sheet piles are a feasible alternative for scour protection and may provide advantages by limiting the required extents of scour protection. Driven sheet piles should be oversized to avoid damage during installation into the gravelly and cobbly alluvium.

• Excavations below river levels should anticipate encountering groundwater and significant seepage inflows requiring groundwater cutoff and isolation strategies for any earthwork requiring dry conditions. We recommend interlocking, steel sheet piles as a feasible approach to slow the inflow of groundwater and river water into these excavations.

• The existing fill soil at the southwest abutment and alluvium are suitable for re-use as structural fill for the Project and can meet the requirements for Select Borrow, WSDOT Standard Specification 9-03.14(2) provided the oversized cobbles and boulders can be screened and removed. Imported fill will be required for the rock fill pad below bridge spread footings, drainage material behind walls, and gravel road surfacing/pavement base course.

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3.1 Seismic Design Considerations The Site area lies within the zone of influence of several earthquake sources including surficial faults, deep instraslab earthquakes, and to a lesser extent, the Cascadia Subduction Zone (CSZ).

The following sections present descriptions of seismic design considerations for the Project.

3.1.1 Ground Response The AASHTO seismic design is based on an earthquake with a 5 percent probability of exceedance (PE) in 50 years (1,000-year return period; AASHTO, 2017). The U.S. Geological Survey has a unified hazard tool (USGS, 2019) with the capability of looking up seismic design parameters for various design events (return periods). The AASHTO amplification factors were used to adjust the parameters for the representative site class. Based on the subsurface conditions encountered in our explorations and following the guidelines in AASHTO Section C.3.10.3.1 (AASHTO, 2017), we recommend that the Site be considered a Site Class C. The recommended ground motion parameters are shown below in Table 1.

Table 1. Seismic Design Parameters Design Parameter Recommended Value

Magnitude (Mw) 5.3

Site Class C

Peak Ground Acceleration (PGA) 0.103g(1)

Short Period Spectral Acceleration (Ss) 0.234g

1-Second Period Spectral Acceleration (S1) 0.074g

Site Coefficient (Fpga) 1.200

Site Coefficient (Fa) 1.200

Site Coefficient (Fv) 1.700

Design Peak Ground Acceleration (As) 0.124g

Design Short Period Spectral Acceleration (SDS) 0.281g

Design 1-Second Period Spectral Acceleration (SD1) 0.126g

Notes: 1. g = gravitational force 2. Based on the latitude and longitude of the Site: 46.2876 °N, 117.9200 °W.

3.1.2 Surficial Ground Rupture The nearest known active fault is a trace of the southeast-northwest trending Wallula fault zone and is located approximately 35 miles southwest of the Site (Personius, S.F., 2017). Due to the suspected long recurrence interval and the proximity of the Site to the


mapped fault trace, the potential for surficial ground rupture at the Site is considered low during the expected life of the Project.

3.1.3 Liquefaction Liquefaction occurs when loose, saturated, and relatively cohesionless soil deposits temporarily lose strength from seismic shaking. The primary factors controlling the onset of liquefaction include intensity and duration of strong ground motion, characteristics of subsurface soil, in situ stress conditions, and the depth to groundwater.

The Washington Department of Natural Resources (DNR) maps the Site as having moderate to high liquefaction susceptibility (DNR, 2004). Given the relative density, grain size distribution, and geologic origin of the soils at the Site, we do not consider liquefaction to be a significant hazard for the Project.

We conducted liquefaction evaluations with the aid of LiquefyPro, a seismically induced liquefaction and settlement analyses software program developed by CivilTech Software (2009) and WSliq, a liquefaction analysis software program that was created as part of an extended research project supported by WSDOT and authored by Steve Kramer (2008). The evaluations are based on the data revealed by the subsurface explorations for the Project.

Our liquefaction evaluations indicate that the relative density and grain size distribution of the alluvium deposits at the Site are not conducive to liquefaction for the AASHTO design earthquake (see Section 3.1.1; AASHTO, 2017). The output of our liquefaction evaluation based on boring AB-02 is included in Appendix C.

3.2 Engineering Properties The engineering properties of the subsurface soils were generalized for engineering analysis purposes. An assessment of the geotechnical soil parameters for each observed major soil unit is summarized in Table 2.

Table 2. Soil Engineering Properties

Soil Unit USCS

Classification

SPT N-Value

(range, R; average, A)

Total Unit Weight (pcf)1

Effective Friction Angle

(degrees) Cohesion

(psf)2

Fill GW R: 14-18 A: 16 120 32 -

Alluvium ML, SM, SP-SM, SP, GW-

GM, GW

R: 4-50+ A: 42 125 36 -

Weathered Basalt

SP-SM, SM, GP

R: 50+ A: 50+ 135 40 -

Notes: 1. Pounds per cubic foot, pcf. 2. Pounds per square foot, psf.

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3.3 Bridge Foundations The subsurface conditions at the Site generally consist of fill overlying alluvium, which in turn overlies weathered basalt bedrock at depth. We consider conventional spread footing foundations or driven pile foundations to be technically feasible for the replacement bridge, assuming that:

• Spread footings bear on granular alluvium and extend below the anticipated scour level or are otherwise protected from scour.

• Driven pile foundations would extend to between Elevation 1775 and 1780 and driven to refusal on the weathered basalt bedrock.

Typically, conventional spread footings offer cost savings, can simplify designs, and require less specialized equipment to install when compared to driven piles. However, excavation into and below the river channel could require significant dewatering efforts to install spread footing foundations and related scour protection. Depending on the river geomorphology and scour potential, spread footings could require more robust scour protection to achieve a similar level of scour risk reduction when compared to driven piles.

Driven piles can better reduce the risk of future scour impacts to the new structure and reduce the footprint of the required scour protection as a result. Driven piles can also be installed relatively quickly and without significant excavation offering construction staging advantages and there are practical ways to verify their capacity in the field during construction. Driven piles commonly used include steel H-piles, steel pipe piles, cast-in-place concrete piles (driven, steel-walled pipe pipes that are in-filled with concrete), and precast, prestressed concrete piles. Based on the subsurface conditions at the Site including gravelly and cobbly alluvium with boulders and basalt bedrock, we recommend relatively stout, HP14X89 H-piles equipped with steel drive points (shoes). Given the rural Project location, damage to adjacent facilities from pile driving vibration does not pose a concern.

3.3.1 Spread Footings If spread footings are used for the replacement bridge foundations and/or the wingwalls, we recommend constructing the footings atop a 12-inch-thick crushed rock fill pad (fill pad) comprised of Crushed Surfacing Base Course (CSBC) per WSDOT Standard Specification 9-03.9(3) (WSDOT, 2020). The compacted CSBC pad should be placed over undisturbed or compacted in-place alluvium deposits.

The fill pad will provide relatively uniform subgrade conditions directly beneath the footings and “bridge” potential hard spots below footings caused by the edges/points of larger cobbles and boulders in the alluvium (if present). The 12-inch-thick fill pad should extend at least 2 feet in all directions beyond the edges of the footings.

Prior to placing the fill pad, the subgrade should be prepared to a relatively firm and level condition that is generally free of protruding cobbles and boulders edges/points, which might require some targeted rock chipping or removal of cobbles/boulders. Voids created from cobble/boulder chipping or removal should be backfilled with compacted CSBC structural fill. An Aspect geotechnical engineer or geologist should evaluate the


foundation subgrade prior to placement of the fill pad and the foundations to verify conditions.

All foundations should bear at least 2 feet below finish grade for frost protection and should extend at least 2 feet below the estimated scour elevation.

Spread Footing Bearing Resistance The bearing resistance values presented below assume all footings are built atop a fill pad and subgrade materials prepared in accordance with Section 3.3.1 above.

• Figure 3 presents the Nominal (unfactored) Bearing Resistances for use in design of 4- to 10-foot-wide footings. These values assume footings are embedded at least 2 feet below the design scour level and the foundation subgrade soils are periodically submerged by high river water levels.

• The recommended Load and Resistance Factor Design (LRFD) resistance factors required to calculate Strength and Extreme Limit State Bearing Resistances from the provided Nominal Bearing Resistances (shown on Figure 3) are provided in Table 3 below.

• Service Limit State Bearing Resistances corresponding to total footing settlement estimates of 1.0 or 1.5 inches to design 4- to 10-foot-wide (effective width) footings are presented on Figure 3. Differential settlement over the footing length are estimated to be about half the total settlement. Settlement is anticipated to occur as loads are applied during construction.

Table 3. LRFD Resistance Factors for Spread Footings

Notes: 1. Value of 0.8 for cast-in-place concrete foundations, or 0.9 for precast concrete foundations.

3.3.2 Driven Piles For driven piles, we recommend HP14X89 H-piles equipped with steel drive points.

Axial Resistance Axial pile resistance analyses were completed in accordance with AASHTO guidelines for the recommended driven piles described above and using the soil conditions observed in our subsurface explorations.

The results of our axial resistance analyses are nominal (ultimate) resistances for both bearing (compression) and uplift (tension) resistance for a single pile or pile group with a minimum center-to-center pile spacing of 2.5B, where B is the pile diameter. The estimated nominal resistance (the sum of the frictional resistance along the side of the pile and the end resistance) is shown graphically on Figures 4 and 5 for the southwest and

Limit State Bearing

Resistance, φb

Shear Resistance to

Sliding, φτ1 Passive Pressure

Resistance to Sliding, φep Strength 0.45 0.8 / 0.9 0.5

Extreme 0.9 0.9 0.9

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northeast abutments, respectively. Liquefaction and related downdrag forces due to seismic settlement are not a design concern; therefore, no liquefaction-induced downdrag loads on the piles are included. Similarly, significant fill placement at the proposed bridge abutments is not anticipated; therefore, downdrag loads due to embankment settlement are not included.

For HP14X89 H-piles driven to refusal on the weathered basalt, nominal axial compressive capacities on the order of 850 kips and uplift capacities on the order of 75 kips can be expected. However, axial compressive resistance of piles driven to refusal on bedrock is often controlled by the pile structural capacity as opposed to the available pile friction and end resistance provided by the bedrock (see Section 10.7.3.2.3 of the AASHTO BDS).

The applicable Resistance Factors corresponding to the strength, service, and extreme limit states are shown in Table 4 and can be used in conjunction with Figures 4 and 5 to determine estimated strength, service, and extreme geotechnical resistances at various pile embedment depths. Pile embedment was assumed to start at approximately Elevation 1809. Frictional shaft resistance was ignored in the upper 5 feet of pile embedment, or to about Elevation 1804, in alignment with AASHTO recommendations. If scour projections and/or the scour protection design indicate that the piles could be exposed below Elevation 1804, additional reductions in the axial resistance should be made.

It is important to recognize that the nominal resistances shown on Figures 4 and 5 are estimates based on static analysis methods from geotechnical borings. It is possible that soil conditions may vary locally at pile locations and should be confirmed by field observations made during driving as discussed in Section 4.1 of this report.

Table 4. Resistance Factors for Driven Pile Design

Limit State

Resistance Factor, ϕ

Bearing Resistance, ϕstat(1) Bearing Resistance, ϕdyn(2), Uplift, ϕup Strength 0.30 0.55(3) 0.25

Service 1.0 1.0 1.0

Extreme 1.0 1.0 1.0

Notes: 1. Applies to nominal resistance as determined by static analysis methods (see Figures 4 and 5). 2. Applies to nominal resistance as determined by dynamic analysis methods during pile driving. 3. Assumes the WSDOT driving formula will be used as the basis for the dynamic analysis and pile

driving construction control.

Settlement Assuming the design and construction of driven pile foundations is completed in accordance with our recommendations contained herein, we estimate that total settlements will be less than about 0.5 inches with differential settlement between the two abutments of less than 0.25 inches. We anticipate any settlement will occur in an elastic manner and almost immediately as the bridge is constructed and loads are applied.


Lateral Resistance Article 4.7.4.2 of the AASHTO LRFD BDS (AASHTO, 2017) states that seismic analysis of single span bridges is not required. However, we understand that lateral load analyses may be performed under certain scenarios and can provide soil parameters for use in evaluation of lateral load resistance upon request.

Minimum Pile Penetration Based on the inferred subsurface conditions at the proposed bridge abutments, we recommend the driven piles be driven to refusal on or within the weathered basalt. We estimate this will occur at approximately Elevation 1780 at the northeast abutment and at approximately Elevation 1775 at the southwest abutment. Some piles may encounter refusal conditions on boulders within the alluvium prior to reaching the basalt. Driving refusal occurs when the pile penetration under continuous driving is greater than 15 blows per inch.

Actual pile depths will need to be evaluated in the field through field observations including evaluation per the WSDOT pile driving formula as specified in Section 6.05.3(12) of the WSDOT Standard Specifications (WSDOT, 2020) to confirm the minimum bearing capacity and sufficient embedment of the piles has been achieved.

Driveability Due to the presence of dense to very dense gravelly and cobbly alluvium, we recommend a pile drivability evaluation be performed to verify the anticipated driving stresses do not exceed damage thresholds for the pile section. If damage is possible, a heavier H-pile section may be needed.

Piles may be driven with vibratory or impact hammers such as single- or double-acting diesel, air, or steam hammers. If piles are driven with a vibratory hammer, we recommend an impact hammer be used to drive the pile over at least the last two feet or to confirm refusal conditions.

For preliminary hammer selection, considering the Site subsurface conditions and recommended driven pile type, we recommend a double-acting diesel hammer with an energy rating of at least 80,000 foot-pounds and minimum ram weight of 6,000 pounds.

3.4 Abutment Design The bridge abutments will be subjected to lateral earth pressures and should consider potential scour impacts. Scour extending below the scour protection and/or abutment footings/pile cap could cause embankment failures, roadway distress, or bridge settlement. Wing walls are not anticipated for the replacement bridge due to the geometry of the approaches and limited fill placement required around the abutments.

3.4.1 Lateral Earth Pressures The lateral earth pressures acting on the abutments for active, at-rest, and seismic conditions are shown below in Table 5. These values assume properly compacted structural fill (as described in Section 5.3 below) and/or undisturbed native soils are present around abutments.

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To invoke active earth pressure conditions, a wall must be capable of yielding laterally at least 0.001 to 0.002H, where H is the exposed height of the wall; otherwise, at-rest conditions should be assumed.

Table 5. Lateral Earth Pressure Parameters

3.4.2 Sliding Resistance Sliding resistance is developed from the friction occurring between the bottom of the foundation and the subgrade soil, and the passive resistance developed from the soil around the foundation.

For passive resistance against the sides of foundations, the nominal passive values provided in Table 3 above may be used for design. For frictional resistance along the bottoms of footings, an unfactored coefficient of 0.6 may be used. LRFD Resistance Factors for determining limit state sliding and passive resistance are provided in Table 3 above.

3.4.3 Drainage Surface runoff from the roadway surface should be diverted or sloped away from abutments to the extent possible. We recommend that structural fill directly behind abutments and walls consist of at least a 12-inch-thick (measured laterally from back of abutment/wall) gravel curtain drain to convey water down to the relatively permeable

Earth Pressure Condition

Backslope Condition

Earth Pressure Coefficient

Equivalent Fluid Density3

(pcf)1

Uniform Lateral Surcharge Pressure4

(psf)1

Active2 Level 0.28 35 0.28S

At-Rest Level 0.44 55 0.44S

Active Seismic Level - - 2H

At-Rest Seismic Level - - 4H

Passive5 - 3.80 475 -

Notes: 1. psf = pounds per square foot; pcf = pounds per cubic foot. 2. To invoke active earth pressure condition, the wall must be capable of yielding laterally at least

0.001 to 0.002H, where H is the exposed height of the wall. 3. The equivalent fluid densities provided above are distributed triangularly along the exposed height of

the wall. The uniform lateral surcharge pressures are distributed uniformly (rectangularly) along the exposed height of the wall.

4. S is the vertical surcharge pressure at the ground surface immediately above/behind the wall. The vertical surcharge pressure causes a lateral earth pressure to act on the wall, which is calculated as the product of S and the appropriate lateral earth pressure coefficient. We recommend a traffic live load surcharge of 250 psf be used for abutment wall design. The resultant uniform rectangular lateral pressure should be applied to the full height of the abutment wall.

5. Ultimate passive pressures are presented; a Strength Limit State resistance factor (ϕep) of 0.50 should be applied for design. Passive resistance within a depth of 2 feet of the ground surface in front of the walls, or within scour depth in front of the walls, should be ignored (whichever is depth is greater).


foundation subgrade stratum below. The curtain drain material should meet the requirements of Gravel Backfill for Walls, WSDOT Standard Specifications 9.03.12(2) (WSDOT, 2020). A woven geotextile separator meeting the requirements of WSDOT Standard Specifications Section 9-33.2(1) Table 3 should be included at the rear of the gravel curtain drain.

3.5 Global Stability We understand that the floodplain and river channel below the southwest abutment will be sloped at approximately 3H:1V and that the floodplain and river channel below the northeast abutment will be unchanged and the existing revetment will be left in-place. We used limit equilibrium methods within Slide (Rocscience, 2018) to evaluate global stability of the bridge abutment walls. In our stability models, we assumed the abutments will be protected from scour by large riprap and assumed a long-term river channel scour elevation of 1798. Based the analyses results, we conclude that for abutment walls extending a minimum of 5 feet below the ground surface, the minimum factor of safety (FOS) for potential failure surfaces extending through the approaches and beneath the abutments will be at least 1.5 and 1.3, under static and seismic (pseudo-static) loading conditions, respectively. If sheet piles are used for scour protection, the calculated factors of safety for global stability will be greater than the riprap scour protection scenario due to the structural reinforcement provided by the sheet piles.

3.6 Steel Sheet Piles Driven steel sheet piles are a feasible alternative for scour protection at the southwest abutment and may provide advantages by limiting the required extents of scour protection for the Project. The subsurface conditions at the southwest abutment include gravelly and cobbly alluvium with boulders that increase in relative density with depth and becomes very dense with SPT N values exceeding 50 blows per foot below about Elevation 1795. Driving steel sheet pile tips below Elevation 1795 will require a large drop hydraulic or diesel hammer or large vibratory hammer and oversized sheet piles with a minimum section modulus of 55 cubic inches per foot. Difficult and hard driving conditions should be expected below Elevation 1795 and driving refusal on boulders is possible. If subject to lateral earth pressures, the recommendations in Section 3.4.1 should be followed.

ASPECT CONSULTING


4 Construction Considerations The subsurface conditions at the Site include dense to very dense, gravelly and cobbly alluvium that contains boulders underlain by basalt bedrock. There is a possibility of obstructions during excavation and pile driving that may include buried cobbles, boulders, and wood debris. The potential for encountered obstructions during excavation and pile driving should be appropriately addressed in the contract documents.

All pile installations, footing subgrade preparation, final abutment slope grading, and structural fill placement should be evaluated by Aspect and completed in accordance with the WSDOT Standard Specifications.

4.1 Driven Pile Installation In general, driven pile installation should follow the guidelines set forth in WSDOT Standard Specifications Section 6-05. The Contractor should submit details of the proposed pile driving equipment and methodology in accordance with the requirements of Section 6-05.3(9) of the WSDOT Standard Specifications. We recommend driving the H-piles without splicing where possible.

Installation of piles may be impacted by the potential presence of obstructions (such as boulders or buried wood in the embankment fill and alluvium). Obstructions encountered during pile driving may cause some of the piles to be driven out-of-plumb, or to “drift” off of the design horizontal location. Also, if significant obstructions are encountered at certain locations, it may be necessary to adjust certain pile locations to avoid the obstructions. Because of this potential effect, some flexibility should be allowed in the design to enable adjustment of pile locations. In certain instances, it may be necessary to alter the size of the pile cap to accommodate the new pile locations. Any such situations which arise during construction should be evaluated on a case-by-case basis by the owner, structural engineer, and Aspect.

4.1.1 Geotechnical Monitoring of Driven Piles All pile installation operations should be observed by the geotechnical engineering field representative who is experienced in the design and observation of driven pile foundations. It is essential that the field representative be present during pile driving to obtain driving rate measurements, blow count data, and hammer data to evaluate if the required nominal resistance has been developed. We recommend that the pile driving criteria and driveability of the pile section and hammer combination be evaluated prior to construction with a Wave Equation Analysis of Pile driving (WEAP) analysis.

4.1.2 Site Subsurface Variation and Pile Lengths Local variations of subsurface conditions along the bridge alignment should be expected. The lengths of certain piles may need to be adjusted in the field based on conditions encountered during driving. Variable pile lengths should be anticipated, and contingency provisions should be included in the contract documents to facilitate adjustment in payments to the Contractor based on actual lengths of piles installed.


4.2 Earthwork Based on the materials encountered in the explorations, and our understanding of the Project, we anticipate Site earthwork can be completed with standard construction equipment such as tracked excavators, dozers, and mobile cranes. The equipment should be capable of excavating over-size material such as large cobbles and boulders. The fill and alluvium may also include oversized material such as debris like wood, buried logs, or other refuse.

Appropriate erosion and sedimentation control measures should be in accordance with the local best management practices (BMPs) and should be installed prior to beginning earthwork activities.

4.2.1 Temporary Excavation Slopes and Temporary Shoring Maintenance of safe working conditions, including temporary excavation stability, is the responsibility of the Contractor. All temporary cuts in excess of 4 feet in height that are not protected by trench boxes or otherwise shored, should be sloped in accordance with Part N of Washington Administrative Code (WAC) 296-155 for worker safety (WAC, 2016). For planning purposes and using guidance provided by the WAC and our Site observations, we classify the Site soils as Type B with a maximum allowable temporary slope inclination of 1H:1V.

We expect temporary slopes may need to be flatter in Site soils with particularly high cobble and boulder content. Selective removal of precariously lodged cobble and boulders in the excavation sidewall should be completed by the Contractor to establish safe working conditions.

With time and the presence of seepage and/or precipitation, the stability of temporary unsupported cut slopes can be significantly reduced. Therefore, all temporary slopes should be protected from erosion by installing a surface water diversion ditch or berm at the top of the slope if precipitation is expected. Surcharge loads such as construction equipment or material stockpiles should be maintained behind the cut slopes a minimum distance equal to the height of the cut.

In addition, the Contractor should monitor the stability of the temporary cut slopes and adjust the construction schedule and slope inclination accordingly. Vibrations created by traffic and construction equipment may cause caving and raveling of the temporary slopes. In such an event, lateral support for the temporary slopes should be provided by the Contractor.

Excavation for new footings and/or scour protection will likely encounter significant groundwater seepage and will require groundwater cutoff and isolation strategies to create suitable conditions for constructing the new footings and placing scour protection elements. Using interlocking, steel sheet piles is a feasible approach to cut off the inflow of groundwater into the excavation.

Driven steel sheet pile considerations are included in Section 3.6. The sheet piles should be designed and constructed to support lateral loads exerted by the retained soil mass and unbalanced hydrostatic pressures. In addition, any surcharge from construction equipment, construction materials, or excavated soils should be included in the shoring

ASPECT CONSULTING


design. The Contractor should be required to submit a shoring/excavation plan for review prior to construction. The plan should contain specific measures for temporary support and protection of all existing utilities and structures. Precautions should be taken during removal of the shoring to minimize disturbance of the river channel, any utilities, and bridge elements.

The Contractor is responsible for control of ground and surface water and should employ sloping, slope protection, ditching, sumps, dewatering, and other measures as necessary to prevent sloughing of soils. The Contractor should also be responsible for design, implementation, and any necessary permits associated with any construction dewatering system used for the Project.

In Table 6 below, we recommend soil properties for design of temporary shoring.

Table 6. Recommended Soil Properties for Temporary Shoring Design

Notes: 1. pcf = pounds per cubic foot; psf = pounds per square foot; deg = degrees

4.2.2 Construction Dewatering In our opinion, groundwater seepage and/or flow into the excavation is largely dependent on the water level in the river and the use of any river diversion/bypass strategies. Based on our explorations and observations, groundwater seepage into the excavations should be expected. It is feasible to manage this seepage with sheet pile groundwater cutoff in combination with sumps and pumps internal to the excavation.

The Contractor should be required to adequately dewater the excavations for footings, so that the footing subgrade preparation and structural fill placement can be completed in dry conditions. Driven steel sheet piles are addressed in Sections 4.2.1 and 3.6. Sumps are often constructed by placing a short section of perforated corrugated steel pipe (or surplus 8- to 12-inch-diameter well screen) in a small hole excavated below the trench bottom elevation. The annular space around the pipe is backfilled with drain rock, with several inches placed inside the casing to help control the pumping of fines. Submersible pumps (trash pumps) are then placed inside the casing and connected to a central discharge pipe.

The Contractor should be responsible for design, implementation, and any necessary permits associated with any construction dewatering system used for the Project.

4.2.3 Subgrade Preparation We recommend constructing footings atop a 12-inch-thick crushed rock fill pad (fill pad) composed of Crushed Surfacing Base Course (CSBC) per WSDOT Standard Specification 9-03.9(3) (WSDOT, 2020). The compacted CSBC pad should be placed over relatively firm and unyielding soil.

Soil Unit Approximate

Elevation Range (ft)

Moist Unit Weight / Saturated Unit Weight

(pcf)1 Friction Angle

(deg)1 Cohesion

(psf)1 Embankment Fill 1810-1802 120/125 32 0

Alluvium 1802-1775 125/130 36 0


The fill pad will provide relatively uniform subgrade conditions directly beneath the footings and “bridge” potential soft spots within the alluvium and/or hard spots below the walls caused by oversize particles. The 12-inch-thick fill pad should extend at least 2 feet in all directions beyond the edges of the footings.

Prior to placing the fill pad, the subgrade should be prepared to a relatively firm and level condition that is generally free of protruding cobbles and boulders edges/points. Voids created from cobble/boulder removal should be backfilled with compacted CSBC structural fill. An Aspect geotechnical engineer or geologist should evaluate the foundation subgrade prior to placement of the fill pad and the foundations to verify conditions.

4.2.4 Structural Fill Recommendations for structural fill materials and the suitability of on-Site soil for re-use as structural fill are included below.

Use of On-Site Soils The on-Site soil generally consists of well-graded gravel with sand, cobbles, and boulders with limited fines, generally meets the requirements for Common Borrow, WSDOT Standard Specification 9-03.14(3), and can be used for structural fill for certain Project applications.

Beneath and Behind Walls Structural fill placed beneath foundations and walls should consist of Crushed Surfacing Base Course (CSBC) per WSDOT Standard Specification 9-03.9(3) (WSDOT, 2020). Structural fill placed directly behind walls should consist of Gravel Backfill for Walls, WSDOT Standard Specifications 9.03.12(2) (WSDOT, 2020).

Beneath Pavement and Gravel Surfacing We recommend structural fill beneath new asphalt pavement consist of crushed surfacing base course (CSBC) or crushed surfacing top course (CSTC) for the pavement base course. Crushed Surfacing Top Course (CSTC) may be used over the CSBC for the upper 2 to 3 inches of the base course section or CSTC may be used for the full base course section.

For a gravel road section, we recommend a minimum gravel layer thickness of 8 inches with 5 inches of CSBC and the upper 3 inches consisting of CSTC.

CSBC and CSTC material is specified in Section 9-03.9(3) of the WSDOT Standard Specifications.

Approach Embankments We provide the recommendations below for structural fill used to construct approach embankments, which will likely consist mostly of on-Site borrow soils:

• Structural fill for approach embankments, if on-Site materials are used, should generally meet the requirements for Common Borrow, WSDOT Standard Specification 9-03.14(3). If imported materials are utilized, they should meet the requirements for Gravel Borrow, WSDOT Standard Specification 9-03.14(1) (WSDOT, 2020).

ASPECT CONSULTING


• We recommend limiting the maximum particle size of the on-Site materials to 12 inches for use as structural fill for approach embankments. The uppermost 6 inches of the approach embankment fill (just below the base course and pavement section) should consist of imported or on-Site crushed rock, gravel, or other free-draining material with particle sizes less than 3 inches.

• We recommend constructing the outermost 3 feet of approach embankment slopes using the on-Site gravel materials or imported gravel materials to help ensure a coarse material gradation and limit potential for the surface of the embankment to deform and/or erode/rill outwards.

• We recommend overbuilding the outer edge of approach embankment slopes by at least 2 feet prior to regrading them to their final configuration. This will ensure the outer face of the approach embankment slopes are adequately compacted and reduce the potential for deformation and erosion.

• Placement and compaction of structural fill for approach embankments during the dry summer months is preferred because the structural fill materials may contain enough fines (silt and clay) to be moisture-sensitive in wet weather, especially the on-Site materials.

Compaction Criteria Soils placed beneath or around the bridge structure/foundations, the roadway embankment, and below paved areas should be considered as structural fill and placed and compacted in general accordance with the methods described in WSDOT Standard Specifications 2-03.3(14) C, Method C (WSDOT, 2020).

The procedure to achieve the specified minimum relative compaction depends on the size and type of compacting equipment, the number of passes, thickness of the layer being compacted, and certain soil properties. When the size of the excavation restricts the use of heavy equipment, smaller equipment can be used, but the soil must be placed in thin-enough lifts to achieve the required compaction.

Generally, loosely compacted soils are a result of poor construction technique or improper moisture content. Soils with a high percentage of silt or clay are particularly susceptible to becoming too wet, and coarse-grained materials easily become too dry, for proper compaction. Silty or clayey soils with a moisture content too high for adequate compaction should be dried as necessary, or moisture conditioned by mixing with drier materials, or other methods.

It should be noted that nuclear densometer testing of materials containing more than 25 percent or more (by volume) of gravel or particles greater than 4 inches in diameter—such as the screened on-Site material—will not give accurate results. This condition may apply to the on-Site alluvium. In this case, we recommend compacting the material as described by WSDOT Standard Specifications for Rock Embankment Construction, Section 2-03.3(14)A (WSDOT, 2020).


5 Recommendations for Continuing Geotechnical Services

Throughout this report, we have provided recommendations where we consider it would be appropriate for Aspect to provide additional geotechnical input to the design and construction process. Additional recommendations are summarized in this section.

5.1 Additional Design and Consultation Services Before construction begins, we recommend that Aspect:

• Continue to meet with the design team, as needed, to address geotechnical questions that may arise throughout the remainder of the design process

• Review the geotechnical elements of the Project plans to see that the geotechnical engineering recommendations are properly interpreted and incorporated into the design

5.2 Additional Construction Services We are available to provide geotechnical engineering and monitoring services during construction. The integrity of the geotechnical elements depends on proper Site preparation and construction procedures. In addition, engineering decisions may have to be made in the field if variations in subsurface conditions become apparent.

During the construction phase of the Project, we recommend that Aspect be retained to perform the following tasks:

• Review applicable submittals relating to geotechnical elements of the Project

• Observe and evaluate driven pile installation

• Observe and evaluate subgrade for all walls and pavements

• Observe temporary excavations and structural fill placement

• Attend meetings by telephone or on-Site, as needed

• Advise on other geotechnical engineering considerations that may arise during construction

The purpose of our observations is to verify compliance with design concepts and recommendations, and to allow design changes or evaluation of appropriate construction methods if subsurface conditions differ from those anticipated prior to the start of construction.

ASPECT CONSULTING


6 References American Association of State Highway and Transportation Officials (AASHTO), 2017,

LRFD Bridge Design Specifications, Customary U.S. Units.

ASTM International (ASTM), 2020, 2020 Annual Book of ASTM Standards, West Conshohocken, Pennsylvania.

Personius, S.F., et. al., 2017, Fault number 846, Wallula fault system, in Quaternary fault and fold database of the United States: U.S. Geological Survey website, https://earthquakes.usgs.gov/hazards/qfaults, accessed September 2, 2020.

Rocscience, 2018, Slide Version 2018 8.020.

U.S. Geological Survey (USGS), 2019, Unified Hazard Tool: https://earthquake.usgs.gov/hazards/interactive/

Washington State Department of Natural Resources (DNR), 2004, Liquefaction Susceptibility and Site Class Maps of Washington State, By County, Washington Division of Geology and Earth Resources Open File Report 2004-20, by Palmer, S.P., S.L. Magsino, E.L. Bilderback, J.L. Poelstra, D.S. Folger, and R.A. Niggemann, 2004, September 2004.

Washington State Department of Natural Resources Division of Geology and Earth Resources (DNR), 2020, Washington Interactive Geologic Map, 2020, online at: https://geologyportal.dnr.wa.gov/, accessed August, 2020.

Washington State Department of Transportation (WSDOT), 2008, Evaluation of Liquefaction Hazards in Washington State, Final Research Report, Agreement T2695, Task 66, Liquefaction Phase III.

Washington State Department of Transportation (WSDOT), 2009, WSDOT Liquefaction Hazard Evaluation System (WSliq).

Washington State Department of Transportation (WSDOT), 2018, Bridge Design Manual (LRFD) Manual M 23-50.18.

Washington State Department of Transportation (WSDOT), 2020, Standard Specifications for Road, Bridge and Municipal Construction, Document M 41-10.

Washington State Legislature (WSL), 2016, Washington Administrative Code (WAC), Chapter 296-155, Part N - Excavation, Trenching, and Shoring, April 19, 2016.

https://earthquake.usgs.gov/hazards/interactive/

https://geologyportal.dnr.wa.gov/


7 Limitations Work for this project was performed for Inter-Fluve, Inc. (Client), and this report was prepared consistent with recognized standards of professionals in the same locality and involving similar conditions, at the time the work was performed. No other warranty, expressed or implied, is made by Aspect Consulting, LLC (Aspect).

Recommendations presented herein are based on our interpretation of site conditions, geotechnical engineering calculations, and judgment in accordance with our mutually agreed-upon scope of work. Our recommendations are unique and specific to the project, site, and Client. Application of this report for any purpose other than the project should be done only after consultation with Aspect.

Variations may exist between the soil and groundwater conditions reported and those actually underlying the site. The nature and extent of such soil variations may change over time and may not be evident before construction begins. If any soil conditions are encountered at the site that are different from those described in this report, Aspect should be notified immediately to review the applicability of our recommendations.

Risks are inherent with any site involving slopes and no recommendations, geologic analysis, or engineering design can assure slope stability. Our observations, findings, and opinions are a means to identify and reduce the inherent risks to the Client.

It is the Client's responsibility to see that all parties to this project, including the designer, contractor, subcontractors, and agents, are made aware of this report in its entirety. At the time of this report, design plans and construction methods have not been finalized, and the recommendations presented herein are based on preliminary project information. If project developments result in changes from the preliminary project information, Aspect should be contacted to determine if our recommendations contained in this report should be revised and/or expanded upon.

The scope of work does not include services related to construction safety precautions. Site safety is typically the responsibility of the contractor, and our recommendations are not intended to direct the contractor’s site safety methods, techniques, sequences, or procedures. The scope of our work also does not include the assessment of environmental characteristics, particularly those involving potentially hazardous substances in soil or groundwater.

All reports prepared by Aspect for the Client apply only to the services described in the Agreement(s) with the Client. Any use or reuse by any party other than the Client is at the sole risk of that party, and without liability to Aspect. Aspect’s original files/reports shall govern in the event of any dispute regarding the content of electronic documents furnished to others.

Please refer to Appendix D titled “Report Limitations and Guidelines for Use” for additional information governing the use of this report.

We appreciate the opportunity to perform these services. If you have any questions please call Andrew Holmson, Associate Geotechnical Engineer, (971) 865-5894.

FIGURES

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Site Location MapGeotechnical Engineering Report

North Fork Touchet River Bridge ReplacementVernon Lane

Dayton, Washington

FIGURE NO.

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Site and Exploration PlanGeotechnical Engineering Report

North Fork Touchet River Bridge ReplacementVernon Lane

Dayton, Washington

PROJECT NO.

200313

FIGURE NO.

2BY:

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Source: Base map provided by Interfluve,Hood River Oregon, Umatilla Fisheries NorthFork Touchet River Mile 1.3-2.0, 100% Design.

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200313 Sept, 2020Dayton, Washington

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Notes:1. Assumes footing embedment depth of at least 2 feet below design scour elevation.2. Apply Resistance Factors to Nominal (Unfactored) Bearing Resistance to calculate

Strength and Extreme Limit State Bearing Resistances. Bearing Resistance Factors: Strength L.S. (AASHTO LRFD BDS Table 10.5.5.2.1‐1) = 0.45;

Extreme Event L.S. (WSDOT GDM 8.10.2) = 0.9

C O N SU LTI N G

Axial UpliftAxial Compression

HP14x89 Driven H-PileAxial Resistance at Southwest

AbutmentGeotechnical Engineering Report

North Fork Touchet River Bridge ReplacementDayton, Washington

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C O N SU LTI N GPROJECT NO.

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Nominal Resistances for HP14x89 H-Pile- Nominal resistances based on methods presented in 2017 AASHTO LRFD BDS.- Assumes no scour impacts to driven piles.- Based on data from Boring AB-01.- Minimum tip elevation is based on driving to refusal on basalt surface.

Minimum tip Elevation 1775 feet

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Nominal Resistances for HP14x89 H-Pile- Nominal resistances based on methods presented in 2017 AASHTO LRFD BDS.- Assumes no scour impacts to driven piles.- Based on data from Boring AB-02.- Minimum tip elevation is based on driving to refusal on basalt surface.

Minimum tip Elevation 1780 feet

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APPENDIX A

Subsurface Explorations

ASPECT CONSULTING

PROJECT NO. 200313 SEPTEMBER 18, 2020 DRAFT A-1

A. Subsurface Explorations Aspect subcontracted Western States Soil Conservation, an experienced and licensed local driller to drill soil borings AB-01 and AB-02 using mud rotary (4.875 inch tricone bit) and HQ rock coring drilling techniques on August 20 and 21, 2020. Drilling was completed with a truck-mounted CME 75 drill rig equipped with a casing advancer. The borings were advanced to approximately 37 and 51 feet below ground surface (bgs). Once drilling was completed, the borings were backfilled with bentonite grout, bentonite chips and capped with gravel at the road surface.

Disturbed samples were obtained at 2.5-foot intervals to 15 feet bgs and 5-foot intervals to depth, in accordance with the Standard Penetration Test (ASTM Method D1586) methodology. This involves driving a 2-inch-outside-diameter split-barrel sampler a distance of 18 inches into the soil with a 140-pound hammer free falling from a distance of 30 inches. The number of blows for each 6-inch interval is recorded, and the number of blows required to drive the sampler the final 12 inches is known as the Standard Penetration Resistance (“N”) or blow count. The resistance, or N-value, provides a measure of the relative density of granular soils or the relative consistency of cohesive soils.

An Aspect engineer was present throughout the field exploration program to observe the drilling procedure, assist in sampling, and to prepare descriptive logs of the exploration. Soils were classified in general accordance with ASTM D2488, Standard Practice for Description and Identification of Soils (Visual-Manual Procedure). The summary exploration log represents our interpretation of the contents of the field logs. The stratigraphic contacts shown on the individual summary logs represent the approximate boundaries between soil types; actual transitions may be more gradual. The subsurface conditions depicted are only for the specific date and locations reported; therefore, are not necessarily representative of other locations and times.

The locations of the borings are shown on Figure 2.

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8

“WITH SILT” or “WITH CLAY” means 5 to 15% silt and clay, denoted by a “-“ in the groupname; e.g., SP-SM ● “SILTY” or “CLAYEY” means >15% silt and clay ● “WITH SAND” or “WITHGRAVEL” means 15 to 30% sand and gravel. ● “SANDY” or “GRAVELLY” means >30% sand andgravel. ● “Well-graded” means approximately equal amounts of fine to coarse grain sizes ● “Poorlygraded” means unequal amounts of grain sizes ● Group names separated by “/” means soilcontains layers of the two soil types; e.g., SM/ML.

Soils were described and identified in the field in general accordance with the methods described inASTM D2488. Where indicated in the log, soils were classified using ASTM D2487 or otherlaboratory tests as appropriate. Refer to the report accompanying these exploration logs for details.

% by Weight

Density³ SPT² Blows/Foot

High

lyOr

gani

cSo

ils

Fine

-Gra

ined

Soi

ls -

50%

1 or

Mor

e Pa

sses

No.

200

Sie

veCo

arse

-Gra

ined

Soi

ls -

Mor

e th

an 5

0%1

Reta

ined

on

No.

200

Sie

ve

Gra

vels

- M

ore

than

50%

1 of C

oars

e Fr

actio

nRe

tain

ed o

n N

o. 4

Sie

ve15

% F

ines

5% F

ines

Sand

s - 5

0%1 o

r Mor

e of

Coa

rse

Frac

tion

Pass

es N

o. 4

Sie

veSi

lts a

nd C

lays

Liqu

id L

imit

Less

than

50%

Silts

and

Cla

ysLi

quid

Lim

it 50

% o

r Mor

e15

% F

ines

5% F

ines

Well-graded GRAVELWell-graded GRAVEL WITH SAND

Poorly-graded GRAVELPoorly-graded GRAVEL WITH SAND

SILTY GRAVELSILTY GRAVEL WITH SAND

CLAYEY GRAVELCLAYEY GRAVEL WITH SAND

Well-graded SANDWell-graded SAND WITH GRAVEL

Poorly-graded SANDPoorly-graded SAND WITH GRAVEL

SILTY SANDSILTY SAND WITH GRAVEL

CLAYEY SANDCLAYEY SAND WITH GRAVEL

SILTSANDY or GRAVELLY SILTSILT WITH SANDSILT WITH GRAVEL

LEAN CLAYSANDY or GRAVELLY LEAN CLAYLEAN CLAY WITH SANDLEAN CLAY WITH GRAVEL

ORGANIC SILTSANDY or GRAVELLY ORGANIC SILTORGANIC SILT WITH SANDORGANIC SILT WITH GRAVELELASTIC SILTSANDY or GRAVELLY ELASTIC SILTELASTIC SILT WITH SANDELASTIC SILT WITH GRAVEL

FAT CLAYSANDY or GRAVELLY FAT CLAYFAT CLAY WITH SANDFAT CLAY WITH GRAVEL

ORGANIC CLAYSANDY or GRAVELLY ORGANIC CLAYORGANIC CLAY WITH SANDORGANIC CLAY WITH GRAVEL

PEAT and othermostly organic soils

GW

GP

GM

GC

SW

SP

SM

SC

ML

CL

OL

MH

CH

OH

PT

Modifier

Organic ChemicalsBTEX = Benzene, Toluene, Ethylbenzene, XylenesTPH-Dx = Diesel and Oil-Range Petroleum HydrocarbonsTPH-G = Gasoline-Range Petroleum HydrocarbonsVOCs = Volatile Organic CompoundsSVOCs = Semi-Volatile Organic CompoundsPAHs = Polycyclic Aromatic Hydrocarbon CompoundsPCBs = Polychlorinated Biphenyls

GEOTECHNICAL LAB TESTSMC = Natural Moisture ContentPS = Particle Size DistributionFC = Fines Content (% < 0.075 mm)GH = Hydrometer TestAL = Atterberg LimitsC = Consolidation TestStr = Strength TestOC = Organic Content (% Loss by Ignition)Comp = Proctor TestK = Hydraulic Conductivity TestSG = Specific Gravity Test

RCRA8 = As, Ba, Cd, Cr, Pb, Hg, Se, Ag, (d = dissolved, t = total)MTCA5 = As, Cd, Cr, Hg, Pb (d = dissolved, t = total)PP-13 = Ag, As, Be, Cd, Cr, Cu, Hg, Ni, Pb, Sb, Se, Tl, Zn (d=dissolved, t=total)

CHEMICAL LAB TESTS

PID = Photoionization DetectorSheen = Oil Sheen TestSPT2 = Standard Penetration TestNSPT = Non-Standard Penetration TestDCPT = Dynamic Cone Penetration Test

<1 = Subtrace1 to <5 = Trace5 to 10 = Few

Dry = Absence of moisture, dusty, dry to the touchSlightly Moist = Perceptible moistureMoist = Damp but no visible waterVery Moist = Water visible but not free drainingWet = Visible free water, usually from below water table

COMPONENTDEFINITIONS

Descriptive Term Size Range and Sieve NumberBoulders = Larger than 12 inchesCobbles = 3 inches to 12 inchesCoarse Gravel = 3 inches to 3/4 inchesFine Gravel = 3/4 inches to No. 4 (4.75 mm)Coarse Sand = No. 4 (4.75 mm) to No. 10 (2.00 mm)Medium Sand = No. 10 (2.00 mm) to No. 40 (0.425 mm)Fine Sand = No. 40 (0.425 mm) to No. 200 (0.075 mm)Silt and Clay = Smaller than No. 200 (0.075 mm)

Metals

ESTIMATED1

PERCENTAGE

MOISTURECONTENT

RELATIVE DENSITY

CONSISTENCY

GEOLOGIC CONTACTS

Very Loose = 0 to 4 ≥ 2'Loose = 5 to 10 1' to 2'Medium Dense = 11 to 30 3" to 1'Dense = 31 to 50 1" to 3"Very Dense = > 50 < 1"

Consistency³Very Soft = 0 to 1 Penetrated >1" easily by thumb. Extrudes between thumb & fingers.Soft = 2 to 4 Penetrated 1/4" to 1" easily by thumb. Easily molded.Medium Stiff = 5 to 8 Penetrated >1/4" with effort by thumb. Molded with strong pressure.Stiff = 9 to 15 Indented ~1/4" with effort by thumb.Very Stiff = 16 to 30 Indented easily by thumbnail.Hard = > 30 Indented with difficulty by thumbnail.

Non-Cohesive or Coarse-Grained Soils

SPT² Blows/Foot

Observed and Distinct Observed and Gradual Inferred

1. Estimated or measured percentage by dry weight2. (SPT) Standard Penetration Test (ASTM D1586)3. Determined by SPT, DCPT (ASTM STP399) or other field methods. See report text for details.

% by Weight Modifier15 to 25 = Little30 to 45 = Some>50 = Mostly

Penetration with 1/2" Diameter Rod

Manual Test

FIELD TESTS

Cohesive or Fine-Grained Soils

Exploration Log Key

DRAFT13

10

8

12

7

7

6

10

10

19

8

18

18

15

10

30

38

28

Backfilled withbentonite grout frombottom to 2 feet bgs,bentonite chips from 2ft to 6-inches bgs, andcapped with gravel tosurface.

Roadway Gravel Base GRAVEL WITH SILT AND SAND (GP-GM); mediumdense, slightly moist, gray; fine to coarse sand; fine tocoarse, subangular to angular gravel.

Fill GRAVEL WITH SAND (GW); medium dense, moist,brown with trace red brown; fine to coarse sand; fine tocoarse, subrounded to subangular gravel.

Quaternary Alluvium (Qal) SANDY SILT (ML); very stiff, moist, brown; non-plastic;fine to medium sand. GRAVEL WITH SILT AND SAND (GW-GM); mediumdense, moist, brown; fine to coarse sand; fine to coarse,subrounded to angular basaltic gravel. GRAVEL WITH SAND, COBBLES, AND BOULDERS(GW); medium dense, moist, brown; medium to coarsesand; fine to coarse, rounded to subangular basalticgravel; subrounded cobbles.

Subtrace woody organics from 12.5 to 15 ft bgs.

Grades to very dense, brown with trace red brown.

FC=4%

FC=2.5%

S1

S2

S3

S4

S5

S6

Operator Work Start/Completion Dates

Blows/footWater Content (%)

AB-01Equipment

Legend

Contractor

1805

1800

1795

AB-01

Tests

CME 75 #8

Mud rotary

Western States SoilConservation, Inc.

Exploration Method(s)

See Exploration Log Key for explanationof symbols

Exploration Completionand Notes

SampleType/ID

Depth to Water (Below GS)

Description

NE

W S

TA

ND

AR

D E

XP

LOR

AT

ION

LO

G T

EM

PLA

TE

P

:\G

INT

W\P

RO

JEC

TS

\200

313

NF

TO

UC

HE

T R

IVE

R B

RID

GE

RE

PLA

CE

ME

NT

.GP

J S

epte

mbe

r 11

, 20

20

Rev

iew

Sta

ge:D

RA

FT

Rev

.2

Top of Casing Elev. (NAVD88)

Blows/6"

5

10

15

8/20/2020 to 8/20/2029

Project Address & Site Specific Location

1810' (est)

Plastic Limit

NA

Split Barrel 2" X 1.375" (SPT)Continuous core 4" ID

No Water Encountered

46.2875, -117.9215 (est)Ground Surface Elev. (NAVD88)

Coordinates (Lat,Lon WGS84)

Autohammer; 140 lb hammer; 30" drop

Logged by: JSJApproved by:

NF Touchet Bridge Replacement - 200313

Depth(feet)

MaterialType

Shane

Sam

ple

Typ

e

Elev.(feet)


Liquid Limit

Geotechnical Exploration Log

5

10

15

Vernon Lane, Dayton, WA, SW Side of NF Touchet River; 35 feet SW ofExisting Bridge

ExplorationLog

Exploration Number

No Soil Sample Recovery

Wat

erLe

vel

Sheet 1 of 2

Depth(ft)

Sampling Method

10 20 30 400 50

DRAFT38

38

23

28

50/3"

50/3"

GRAVEL WITH SAND, COBBLES, AND BOULDERS(GW); very dense, moist, brown with dark gray gravel;medium to coarse sand; fine to coarse, rounded tosubangular basaltic gravel; subrounded cobbles.

Switch from mud rotary to HQ coring.

Switch from HQ coring to mud rotary.

Weathered Basalt GRAVEL WITH SAND, COBBLES, AND BOULDERS(GP); very dense, moist, gray brown to dark gray; mediumto coarse sand; fine to coarse, subangular to angularbasaltic gravel (slightly to moderately weathered R3basalt).

Bottom of exploration at 37 ft. bgs.

S7

S8

S9

S10



AB-01Equipment

Legend

Contractor

1785

1780

1775

AB-01

Tests

CME 75 #8

Mud rotary





SampleType/ID


Description

NE

W S

TA

ND

AR

D E

XP

LOR

AT

ION

LO

G T

EM

PLA

TE

P

:\G

INT

W\P

RO

JEC

TS

\200

313

NF

TO

UC

HE

T R

IVE

R B

RID

GE

RE

PLA

CE

ME

NT

.GP

J S

epte

mbe

r 11

, 20

20

Rev

iew

Sta

ge:D

RA

FT

Rev

.2


Blows/6"

25

30

35

8/20/2020 to 8/20/2029


1810' (est)

Plastic Limit

NA

Split Barrel 2" X 1.375" (SPT)Continuous core 4" ID







Depth(feet)

MaterialType

Shane

Sam

ple

Typ

e

Elev.(feet)


Liquid Limit


25

30

35

Vernon Lane, Dayton, WA, SW Side of NF Touchet River; 35 feet SW ofExisting Bridge

ExplorationLog

Exploration Number


Wat

erLe

vel

Sheet 2 of 2

Depth(ft)

Sampling Method

10 20 30 400 50

DRAFT9

4

5

12

10

6

5

2

2

12

10

6

13

25

26

2

9

23

Backfilled withbentonite grout frombottom to 2 feet bgs,bentonite chips from 2ft to 6-inches bgs, andcapped with gravel tosurface.

Roadway Gravel Base GRAVEL WITH SILT AND SAND (GP-GM); mediumdense, slightly moist, gray; fine to coarse sand; fine tocoarse, subangular to angular gravel.

Quaternary Alluvium (Qal) GRAVEL WITH SAND AND COBBLES (GW); loose,moist, brown; coarse sand; fine to coarse, subrounded toangular gravel; subrounded cobbles; trace woody organics.

Grades to medium dense, gray brown to dark gray.

Grades to very loose, slightly moist.

GRAVEL WITH COBBLES AND BOULDERS (GW);medium dense, dark gray, moist; coarse, subrounded toangular basaltic gravel; subrounded cobbles.

GRAVEL WITH SAND, COBBLES, AND BOULDERS(GW); very dense, moist, gray brown to dark gray; mediumto coarse grave; fine to coarse, subrounded to angularbasaltic gravel; subrounded cobbles.

Grades to dense, very moist to wet.

SAND (SP); dense, very moist to wet, dark gray; mediumto coarse sand.

FC=1.1%

S1

S2

S3

S4

S5

S6



AB-02Equipment

Legend

Contractor

1810

1805

1800

1795

AB-02

Tests

CME 75 #8

HWT Casing Advancer





SampleType/ID


Description

NE

W S

TA

ND

AR

D E

XP

LOR

AT

ION

LO

G T

EM

PLA

TE

P

:\G

INT

W\P

RO

JEC

TS

\200

313

NF

TO

UC

HE

T R

IVE

R B

RID

GE

RE

PLA

CE

ME

NT

.GP

J S

epte

mbe

r 11

, 20

20

Rev

iew

Sta

ge:D

RA

FT

Rev

.2


Blows/6"

5

10

15

8/21/2020


1814' (est)

Plastic Limit

NA

Split Barrel 2" X 1.375" (SPT)







Depth(feet)

MaterialType

Shane

Sam

ple

Typ

e

Elev.(feet)


Liquid Limit


5

10

15

Vernon Lane, Dayton, WA, NE of NF Touchet River; 35 feet NE of ExistingBridge

ExplorationLog

Exploration Number


Wat

erLe

vel

Sheet 1 of 3

Depth(ft)

Sampling Method

10 20 30 400 50

DRAFT9

19

27

23

50/3"

3

21

24

25

28

50/3"

18

48

50/3"

GRAVEL WITH SAND, COBBLES, AND BOULDERS(GW); dense to very dense, very moist to wet, dark gray;medium to coarse sand; fine to coarse, subrounded toangular basaltic gravel; subrounded cobbles.

SAND WITH SILT AND GRAVEL (SP-SM); very dense,very moist, brown with red brown; fine to coarse sand;fine, subrounded to angular gravel. Switch to mud rotary.

GRAVEL WITH COBBLES AND BOULDERS (GW);dense, very moist, gray brown to dark gray; fine to coarse,rounded to subangular gravel.

SILTY SAND WITH GRAVEL (SM); dense, very moist,gray brown with orange mottling; non-plastic; fine tocoarse sand; fine to coarse, subrounded to subangulargravel.

GRAVEL WITH COBBLES AND BOULDERS (GW);dense, very moist, gray brown to dark gray; fine to coarse,rounded to subangular basaltic gravel; subroundedcobbles. GRAVEL WITH SILT AND SAND (GW-GM); dense, verymoist, gray brown to red brown with orange mottling;non-plastic; fine to coarse sand; fine to coarse,subrounded to subangular gravel.

Weathered Basalt SILTY SAND WITH GRAVEL (SM); very dense, moist,gray brown to red brown; non-plastic; fine to coarse sand;fine, subrounded to subangular gravel (residual soil tocompletely weathered R0 basalt).

FC=8.8%

FC=15.8%

S7

S8

S9

S10

S11

BS

11A



AB-02Equipment

Legend

Contractor

1790

1785

1780

1775

AB-02

Tests

CME 75 #8

HWT Casing Advancer





SampleType/ID


Description

NE

W S

TA

ND

AR

D E

XP

LOR

AT

ION

LO

G T

EM

PLA

TE

P

:\G

INT

W\P

RO

JEC

TS

\200

313

NF

TO

UC

HE

T R

IVE

R B

RID

GE

RE

PLA

CE

ME

NT

.GP

J S

epte

mbe

r 11

, 20

20

Rev

iew

Sta

ge:D

RA

FT

Rev

.2


Blows/6"

25

30

35

8/21/2020


1814' (est)

Plastic Limit

NA








Depth(feet)

MaterialType

Shane

Sam

ple

Typ

e

Elev.(feet)


Liquid Limit


25

30

35


ExplorationLog

Exploration Number


Wat

erLe

vel

Sheet 2 of 3

Depth(ft)

Sampling Method

10 20 30 400 50

DRAFT46

50/6"

50/3"

50/2"

GRAVEL WITH SAND, COBBLES, AND BOULDERS(GP); very dense, very moist, gray brown to dark gray;medium to coarse sand; fine to coarse, subrounded tosubangular basaltic gravel (moderately to highly weatheredR0-R1 basalt). SILTY SAND (SM); very dense, moist, red brown with tanmottling; non-plastic; fine to coarse sand; trace fine,subangular gravel (highly weathered R0-R1 basalt).

GRAVEL WITH SAND, COBBLES, AND BOULDERS(GP); very dense, moist, gray brown to dark gray; mediumto coarse sand; fine to coarse, subangular to angularbasaltic gravel (moderately weathered R2 basalt).

Bottom of exploration at 50.2 ft. bgs.

Note: Drilling was conducted with HWT casing advancer to25 ft bgs and mud rotary to bottom of exploration.

S12

AS

12B

S13

S14



AB-02Equipment

Legend

Contractor

1770

1765

1760

1755

AB-02

Tests

CME 75 #8

HWT Casing Advancer





SampleType/ID


Description

NE

W S

TA

ND

AR

D E

XP

LOR

AT

ION

LO

G T

EM

PLA

TE

P

:\G

INT

W\P

RO

JEC

TS

\200

313

NF

TO

UC

HE

T R

IVE

R B

RID

GE

RE

PLA

CE

ME

NT

.GP

J S

epte

mbe

r 11

, 20

20

Rev

iew

Sta

ge:D

RA

FT

Rev

.2


Blows/6"

45

50

55

8/21/2020


1814' (est)

Plastic Limit

NA








Depth(feet)

MaterialType

Shane

Sam

ple

Typ

e

Elev.(feet)


Liquid Limit


45

50

55


ExplorationLog

Exploration Number


Wat

erLe

vel

Sheet 3 of 3

Depth(ft)

Sampling Method

10 20 30 400 50

ASPECT CONSULTING

APPENDIX B

Laboratory Testing Results

ASPECT CONSULTING

B-2 DRAFT PROJECT NO. 200313 SEPTEMBER 18, 2020

B. Geotechnical Laboratory Testing Results Laboratory tests were conducted on selected soil samples to characterize certain engineering (physical) properties of the Site soils. Laboratory testing included determination of fines content and grain-size distribution, in general accordance with appropriate ASTM test methods. Test procedures are discussed below.

The fines content of selected samples was analyzed in general accordance with ASTM D1140, Standard Test Methods of Determining the Amount of Material Finer than 75-mm (No. 200) Sieve in Soils by Washing. The grain-size distribution of selected samples was analyzed in general accordance with ASTM D6913, Standard Test Method for Particle-Size Analysis of Soils without hydrometer determination of fines content.

The results of the fines content tests are presented in tabular form in this appendix. The results of the grain-size distribution tests are presented as curves in this appendix, plotting percent finer by weight versus grain size. All geotechnical laboratory testing results are incorporated into the boring logs in Appendix A.

GRADATION REPORTReport Number: 82201268.0001Service Date: 09/02/20 700 NE 55th Ave Report Date: 09/11/20 Portland, OR 97213-3150Task: North Fork Touchet River Bridge Replacement #200313 503-659-3281Client Project

Aspect Consulting, LLC Aspect Consulting 2020 Lab TestingAttn: Andrew Holmson 700 NE 55th Avenue522 SW 5th Ave Portland, OR 97213Suite 1300 Portland, OR 97209 Project Number: 82201268

Services:

Terracon Rep.: Jachin Encarnacion Reported To: Contractor: Report Distribution:(1) Aspect Consulting, LLC, Andrew Holmson

Reviewed By: ____________________________________ Charles Schneider Laboratory ManagerThe tests were performed in general accordance with applicable ASTM, AASHTO, or DOT test methods. This report is exclusively for the use of the client indicated above and shall not be reproduced except in full without the written consent of our company. Test results transmitted herein are only applicable to the actual samples tested at the location(s) referenced and are not necessarily indicative of the properties of other apparently similar or identical materials.

AF0004, 6-17-11, Rev.2 Page 1 of 1

Summary: Terracon representative performed ASTM D6913 (Grain Size Analysis) testing on (3) samples of material obtained by Aspect Consultants. Material was Well-Graded Gravel with Sand (GW), sampled for the North Fork Touchet River Bridge Replacement project. The material was obtained from boring IDs AB-01 and AB-02. See attached report for details.

0

5

10

15

20

25

30

35

40

45

50

55

60

65

70

75

80

85

90

95

100

0.0010.010.1110100

3/4 1/23/8 30 403 60

HYDROMETERU.S. SIEVE OPENING IN INCHES16 20

100

90

80

70

60

50

40

30

20

10

0

U.S. SIEVE NUMBERS

44 10063 2 10 14 506 2001.5 81 140

PER

CEN

T FI

NER

BY

WEI

GH

TPE

RC

ENT C

OAR

SER

BY W

EIGH

T

GRAIN SIZE DISTRIBUTIONASTM D422 / ASTM C136

PROJECT NUMBER: 82201268

SITE:

PROJECT: Aspect Consulting 2020 Lab Testing

CLIENT:700 NE 55th Ave

Portland, OR

LAB

OR

ATO

RY

TES

TS A

RE

NO

T VA

LID

IF S

EPAR

ATE

D F

RO

M O

RIG

INAL

RE

POR

T.

GR

AIN

SIZ

E: U

SCS

1 8

2201

268

- AS

PEC

T C

ON

SULT

ING

202

0 LA

B TE

STI

NG

.GPJ

TER

RAC

ON

_DAT

ATEM

PLA

TE.G

DT

9/1

0/20

AB-01AB-01AB-02

fine coarse finemediumCOBBLES GRAVEL SAND SILT OR CLAY

D30

D60

BORING ID

1"3/4"1/2"3/8"#4#8#16#30#50#100#200

100.095.0671.1263.3642.3328.519.012.398.165.764.02

1 1/2"1"

3/4"1/2"3/8"#4#8#16#30#50#100#200

100.094.8780.4466.3457.939.5125.9917.1511.076.494.062.49

100.061.1345.8136.7529.5217.979.775.232.921.871.411.09

1 1/2"1"

3/4"1/2"3/8"#4#8#16#30#50#100#200CC

CU

coarse

D10

WELL-GRADED GRAVEL with SAND (GW)



57.760.582.0

38.337.016.9

4.02.51.1

0.00.00.0

2.5 - 3.515 - 165 - 6

GWGWGW

8.504 10.172 24.5012.545 2.904 9.6740.405 0.51 2.407

20.98 19.93 10.181.88 1.62 1.59

Sieve

REMARKS

SOIL DESCRIPTION% Finer% Finer SieveSieve% Finer

USCS% CLAY% FINES% SILT% SAND% GRAVEL% COBBLESDEPTH

COEFFICIENTS

GRAIN SIZE

GRADATION REPORTReport Number: 82201268.0002Service Date: 09/02/20 700 NE 55th Ave Report Date: 09/11/20 Portland, OR 97213-3150Task: North Fork Touchet River Bridge Replacement #200313 503-659-3281Client Project

Aspect Consulting, LLC Aspect Consulting 2020 Lab TestingAttn: Andrew Holmson 700 NE 55th Avenue522 SW 5th Ave Portland, OR 97213Suite 1300 Portland, OR 97209 Project Number: 82201268

Services:

Terracon Rep.: Jordan Real Reported To: Contractor: Report Distribution:(1) Aspect Consulting, LLC, Andrew Holmson

Reviewed By: ____________________________________ Charles Schneider Laboratory ManagerThe tests were performed in general accordance with applicable ASTM, AASHTO, or DOT test methods. This report is exclusively for the use of the client indicated above and shall not be reproduced except in full without the written consent of our company. Test results transmitted herein are only applicable to the actual samples tested at the location(s) referenced and are not necessarily indicative of the properties of other apparently similar or identical materials.

AF0004, 6-17-11, Rev.2 Page 1 of 1

Summary: Terracon representative performed ASTM D1140 (Amount of Material Finer than #200 Sieve) testing on (2) samples of material obtained by Aspect Consultants. Material was not analyzed for USCS classification. It was sampled for the North Fork Touchet River Bridge Replacement project. The material was obtained from boring ID AB-02. See attached report for details.

0

5

10

15

20

25

30

35

40

45

50

55

60

65

70

75

80

85

90

95

100

0.0010.010.1110100

3/4 1/23/8 30 403 60

HYDROMETERU.S. SIEVE OPENING IN INCHES16 20

100

90

80

70

60

50

40

30

20

10

0

U.S. SIEVE NUMBERS

44 10063 2 10 14 506 2001.5 81 140

PER

CEN

T FI

NER

BY

WEI

GH

TPE

RC

ENT C

OAR

SER

BY W

EIGH

T

GRAIN SIZE DISTRIBUTIONASTM D422 / ASTM C136

PROJECT NUMBER: 82201268

SITE:

PROJECT: Aspect Consulting 2020 Lab Testing

CLIENT:700 NE 55th Ave

Portland, OR

LAB

OR

ATO

RY

TES

TS A

RE

NO

T VA

LID

IF S

EPAR

ATE

D F

RO

M O

RIG

INAL

RE

POR

T.

GR

AIN

SIZ

E: U

SCS

1 8

2201

268

- AS

PEC

T C

ON

SULT

ING

202

0 LA

B TE

STI

NG

.GPJ

TER

RAC

ON

_DAT

ATEM

PLA

TE.G

DT

9/1

0/20

AB-02AB-02

fine coarse finemediumCOBBLES GRAVEL SAND SILT OR CLAY

D30

D60

BORING ID

#200 8.79 #200 15.75

CC

CU

coarse

D10

8.815.8

30 - 3135 - 36

Sieve

REMARKS

SOIL DESCRIPTION% Finer% Finer SieveSieve% Finer

USCS% CLAY% FINES% SILT% SAND% GRAVEL% COBBLESDEPTH

COEFFICIENTS

GRAIN SIZE

APPENDIX C

Liquefaction Analysis Results

Liqu

efyP

ro

C

ivilT

ech

Softw

are

USA

w

ww

.civ

iltec

h.co

m

Aspect Consulting, LLC

LIQUEFACTION ANALYSISNorth Fork Touchet Bridge Replacement

C-1

Hole No.=AB-02 Water Depth=6 ft Surface Elev.=1814 Magnitude=5.3Acceleration=0.124g

(ft)0

10

20

30

40

50

60

70

9 125 1.1

16 125 1.1

4 125 1.1

16 125 1.1

51 125 1.1

32 125 1.1

46 125 1.1

50 125 12

45 125 8.8

50 125 12

100 135 15.8

100 135 0

100 135 0

Alluvium

Alluvium

AlluviumAlluviumAlluviumAlluvium

Alluvium

Weathered Basalt

Weathered Basalt

Raw Unit FinesSPT Weight %

Shear Stress Ratio

CRR CSR fs1Shaded Zone has Liquefaction Potential

0 2Soil DescriptionFactor of Safety

0 51Settlement

SaturatedUnsaturat.

S = 0.00 in.

0 (in.) 1

fs1=1

APPENDIX D

Report Limitations and Guidelines for Use

ASPECT CONSULTING

REPORT LIMITATIONS AND GUIDELINES FOR USE

Geoscience is Not Exact The geoscience practices (geotechnical engineering, geology, and environmental science) are far less exact than other engineering and natural science disciplines. It is important to recognize this limitation in evaluating the content of the report. If you are unclear how these "Report Limitations and Guidelines for Use" apply to your project or property, you should contact Aspect Consulting, LLC (Aspect).

This Report and Project-Specific Factors Aspect’s services are designed to meet the specific needs of our clients. Aspect has performed the services in general accordance with our agreement (the Agreement) with the Client (defined under the Limitations section of this project’s work product). This report has been prepared for the exclusive use of the Client. This report should not be applied for any purpose or project except the purpose described in the Agreement.

Aspect considered many unique, project-specific factors when establishing the Scope of Work for this project and report. You should not rely on this report if it was:

• Not prepared for you;

• Not prepared for the specific purpose identified in the Agreement;

• Not prepared for the specific subject property assessed; or

• Completed before important changes occurred concerning the subject property, project, or governmental regulatory actions.

If changes are made to the project or subject property after the date of this report, Aspect should be retained to assess the impact of the changes with respect to the conclusions contained in the report.

Reliance Conditions for Third Parties This report was prepared for the exclusive use of the Client. No other party may rely on the product of our services unless we agree in advance to such reliance in writing. This is to provide our firm with reasonable protection against liability claims by third parties with whom there would otherwise be no contractual limitations. Within the limitations of scope, schedule, and budget, our services have been executed in accordance with our Agreement with the Client and recognized geoscience practices in the same locality and involving similar conditions at the time this report was prepared

Property Conditions Change Over Time This report is based on conditions that existed at the time the study was performed. The findings and conclusions of this report may be affected by the passage of time, by events such as a change in property use or occupancy, or by natural events, such as floods,

ASPECT CONSULTING

earthquakes, slope instability, or groundwater fluctuations. If any of the described events may have occurred following the issuance of the report, you should contact Aspect so that we may evaluate whether changed conditions affect the continued reliability or applicability of our conclusions and recommendations.

Geotechnical, Geologic, and Environmental Reports Are Not Interchangeable

The equipment, techniques, and personnel used to perform a geotechnical or geologic study differ significantly from those used to perform an environmental study and vice versa. For that reason, a geotechnical engineering or geologic report does not usually address any environmental findings, conclusions, or recommendations (e.g., about the likelihood of encountering underground storage tanks or regulated contaminants). Similarly, environmental reports are not used to address geotechnical or geologic concerns regarding the subject property.

We appreciate the opportunity to perform these services. If you have any questions please contact the Aspect Project Manager for this project.

basis of design report | 60% appendix 7

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