GeoRpt_Clark Creek_OR Hwy 35

Draft Geotechnical Data

OR FS ERFO 2007(1)-11(1)

Highway 35 Betterment

This document is a draft and should NOT be relied upon to determine final conditions for bidding.

Final documents will be available during the advertisement period.

Draf t

Intentionally blank.

Preliminary Geotechnical Report No. 02-09

Oregon Highway 35 Betterment Clark Creek Bridge Replacement

Foundation Investigation

OR FS ERFO 2007(1) - 11(1), Mount Hood National Forest

Hood River County, Oregon March, 2009Draf i

CONTENTS

SECTION PAGE

1. Introduction 1

2. Surface Conditions 1

3. Subsurface Investigations 1

3.1 Boring Summaries 1

3.2 Groundwater Levels 2

4. Laboratory Testing 2

5. Bridge Foundation Considerations 3

5.1 Spread Footings 3

5.2 Driven Piles 3

5.3 Drilled Shafts 3

6. Drilled Shaft Foundation Analysis and Design 3

6.1 Soil Strength Design Parameters 3

6.2 Design Loads 4

6.3 Scour Recommendations 5

6.4 Earthquake Engineering 5

6.5 Liquefaction 6

6.6 Preliminary Drilled Shaft Recommendations 7

6.7 Settlement 8

6.8 Lateral Analysis 8

7. Drilled Shaft Construction Considerations 9

8. Approach Embankments and Abutment Wall Design 9

9. Use of This Report 10

10. References 11

FIGURES

Figure 1. Project Location Map ii Figure 2. 5-Percent-Damped-Design Response Spectrum 6

TABLES

TABLE 1. Subsurface Layers and Strength Parameters 4 TABLE 2. Seismic Parameters for Design Earthquake (7% PE in 75 yrs.) 5 TABLE 3. Preliminary Drilled Shaft Recommendations 7 TABLE 4. Recommended Soil Parameters for Lateral Analysis 8 TABLE 5. Recommended Soil Parameters for Abutment Wall Design 10

APPENDICES

APPENDIX A: Boring Location Map APPENDIX B: Boring logs CC-1 and CC-2 APPENDIX C: Unified Soil Classification System APPENDIX D: Laboratory Reports APPENDIX E: Clark Creek Graphical Boring Logs APPENDIX F: SPT N-Value Correction Spreadsheets APPENDIX G: Drilled Shaft Design Charts – Axial Capacity and Settlement ii

FIGURE 1. Location Map for Oregon Highway 35 Clark Creek Bridge.

CLARK CREEK BRIDGE

N

1 MILE

1. INTRODUCTION

This report provides foundation investigation information and design recommendations for a new bridge structure at Clark Creek on Oregon Highway 35 on the east side of Mount Hood, Oregon (Figure 1). The bridge will be constructed as part of an overall larger construction project that will raise the elevation of the existing highway between a three-mile long section of the highway between Clark Creek on the south end and the East Fork Hood River on the north end.

The project is intended to provide greater protection of this section of highway from periodic debris flows that emanate from the valleys of Clark and Newton Creeks on the eastern slopes of Mount Hood and bury, damage, or destroy portions of the roadway, causing closure of the highway for extended time periods while repairs are made.

This report provides preliminary foundation recommendations for initial bridge design based on preliminary loading information. A second report containing finalized foundation recommendations will be provided to the WFLHD Structures Section once the bridge design process has begun and the actual bridge geometry and design loads of the new structures have been determined.

2. SURFACE CONDITIONS

The highway at Clark Creek is located on a broad, forested alluvial fan that slopes gently to the north. The alluvial fan consists of sand, gravel, cobbles, and boulders deposited by fluvial process and debris flows of Clark and Newton Creeks, East Fork Hood River, and several smaller streams.

3. SUBSURFACE INVESTIGATIONS

Two foundation investigation borings were conducted at the bridge site. The borings are identified as CC-1 and CC-2.

No survey information was available to locate the borings at the time the subsurface investigation was performed. The borings were drilled on the east side of the highway, approximately 100 feet north and south of the creek and 10 to 20 feet east of the pavement edge. The ground surface elevations of the borings were determined from topographic contours on preliminary bridge plans. Approximate boring locations are shown on the Boring Location Map in Appendix A.

3.1 Boring Summaries

Logs of borings are contained in Appendix B. Summarized boring information is presented below:

Clark Creek borings CC-1 and CC-2 were drilled at elevations 4256 and 4153.5 feet, respectively. Both borings were advanced to a depth of 80 feet using tri-cone, rotary drilling methods and 4.5 inch diameter steel casing. The subsurface materials encountered were similar to the surface materials described above, consisting predominantly of fine to medium, moist to wet, gray, generally poorly-graded sand, gravel, cobbles, and boulders that were visually classified as SP-SM and GP-GM in the Unified Soil Classification System (Appendix C). Because coring was not performed, the presence of boulders was inferred by the driller based on drilling resistance, action, and speed. Boulders on the order of 1-5 feet in diameter were inferred in this manner.

Sampling consisted of Standard Penetration Tests performed at 2.5 foot intervals to approximately 15 feet depth, then 5 foot intervals to the bottom depth of 80 feet. The Standard Penetration Test (SPT) consists of using a 140 pound hammer with a 30 inch drop to drive a two inch outside diameter split-barrel sampler 18 inches below the bottom of the bore hole and recording the number of blows for each six-inch increment of penetration. The last two numbers (for the final 12 inches of penetration) are added together to determine the blows per foot (bpf), which is known as the N-value. SPT N-values in boring CC-1 ranged from 2 bpf (very loose) to 50 blows for less than 6 inches of penetration (very dense). SPTs having 50 hammer blows with less than 6 inches of penetration of the split spoon indicate an N-value greater than 100 bpf and are considered refusal. Uncorrected SPT N-values in boring CC-2 ranged from 28 bpf (medium dense) to 50 blows for less than 6 inches of penetration (very dense). The average N-value in boring CC-1 and CC-2 was 65 bpf.

3.2. Groundwater Levels

Direct water level measurements were not made in the borings because drilling mud was pumped into the holes to advance the borings. The water level in the borings was estimated based on the moisture in the SPT samples.

The ground water level at the bridge location is likely to rise and fall with the water level in the adjacent creek. Groundwater levels fluctuate. Groundwater levels are likely to rise during spring thaw and following periods of heavy precipitation. Groundwater levels may vary significantly over time due to debris flow and glacial outburst events that can occur upstream from the bridge site.

4. LABORATORY TESTING

Samples consisting of one, two, or three combined SPT samples representing varying depths in borings CC-1 and CC-2 were submitted to the WFLHD Vancouver Materials Testing Laboratory for soil classification, Atterberg Limits, and natural moisture.

Laboratory test reports, identified by lab numbers W-08-1236-SO through W-08-1240- SO, are contained in Appendix D.

Samples were classified in the Unified Soil Classification System (USCS) as “SM – silty sand and silty sand with gravel”, “SP-SM – poorly graded sand with silt and gravel”, “SW-SM – well graded sand with silt and gravel”, and as “GP-GM – poorly graded gravel with silt and sand”.

All of the samples were non-plastic. Natural moistures ranged from 15.9 to 34.5 percent and the percent fines passing the no. 200 sieve ranged from 10.7 to 15.0 percent.

5. BRIDGE FOUNDATION CONSIDERATIONS

5.1 Spread Footings

Spread footings are suitable for use in the gravelly sand foundation materials at Clark Creek. Spread footings are usually cost effective when constructed at depths up to 10 feet below final grade; however, the WFLHD Hydraulics Section recommended that a scour depth of 20 feet below the existing stream channels be used for design of foundations, which precluded spread footings from further consideration.

5.2 Driven Piles

The existing bridge is located approximately 15 feet above the channel bottoms and the new roadway will be elevated five feet above the existing grade. Depending on the elevations at which piles were driven, it is possible that scour at the bridges could result in 30 feet of pile being exposed. Exposure of 30 feet of pile following an extreme scour event would likely result in buckling of the piles and bridge failure. In addition, a wave equation analysis indicated that piles were likely to become structurally damaged in the medium dense to very dense sands and gravels before they could be driven below the scour elevation. Therefore, driven piles were precluded from further consideration.

5.3 Drilled Shafts

Drilled shafts were selected as the preferred foundation alternative because they will be the most economical method to transmit the bridge loads below the design scour elevation.

6. DRILLED SHAFT FOUNDATION ANALYSIS AND DESIGN

6.1 Soil Strength Design Parameters

The materials encountered both investigation borings were cohesionless mixtures of sand, gravel, cobbles, and boulders. Appendix D contains graphical logs of the borings showing summarized subsurface information.

The Standard Penetration Test (SPT) N-values were corrected for hammer energy and overburden pressure to determine the N60 and (N1)60 values. N60 values were corrected for hammer efficiency only. (N1)60 values were corrected for hammer efficiency and overburden pressure. The calculations for the corrected N60 and (N1)60 values are contained in spreadsheet format in Appendix E.

The SPT values indicate generally dense to very dense materials, with a few zones of very loose to medium dense materials. The subsurface materials at each site were divided into layers based on the relative density indicated by the SPT values. Note that the soil profile was divided based on N60 values (N-values corrected only for hammer efficiency) rather than (N1)60 values since drilled shaft design philosophy is correlated to N60 values. The layers and their associated design parameters are summarized in Table 1.

TABLE 1. Subsurface Layers and Strength Parameters.

Soil Layer

Elevation (feet)

Soil Description N60 φ’ (deg.)

Cohesion (psf)

Moist Unit Weight

(pcf)

1 > 4160 New Fill (Sandy Gravel) - 34 0 130

2 4147 – 4160 Sand 11 32 0 120

3 4128 – 4147 Cohesionless

IGM 81 40 0 135

4 4110 – 4128 Sand 49 37 0 130

5 < 4128 Cohesionless

IGM 91 42 0 135

NOTES:

1. IGM = Intermediate Geomaterial, term used to describe very dense or hard soils with SPT N-values greater than 50 blows per foot.

2. φ’ = effective friction angle.

6.2 Design Loads

WFLHD Structures provided preliminary axial dead loads and live loads for the previously proposed Newton Creek Bridge. The loads are anticipated to be similar for the Clark Creek Bridge. Individual load combinations for LRFD limit states were not provided. The unfactored loads are summarized as follows:

Abutments Dead Load (DL) 680 kips Live Load (LL) 175 kips DL + LL 855 kips

The recommendations below assume that two drilled shafts will be used to carry the load at each abutment, thus the design DL+LL is 427.5 kips per drilled shaft. Since factored load combinations were not provided, allowable stress design methods were used to develop a preliminary estimate of drilled shaft tip elevations. A factor of safety of 2.8 was applied to the DL+LL in order to determine the required lengths of drilled shafts.

The ultimate capacity used to set the uppermost tip elevations is 1197 kips per shaft.

Downdrag loads due to settlement are not anticipated.

6.3 Scour Recommendations

A scour depth of 20 feet below the existing channel bottom has been recommended by the WFLHD Hydraulics Section for the design of bridge foundations at Clark Creek. The design scour elevation is 4125 feet.

6.4 Earthquake Engineering

Seismic sources that contribute to the regional seismic hazard include shallow crustal sources (local faults and gridded seismicity) and the Cascadia Subduction Zone inter-plate (mega-thrust) earthquakes.

The procedures outlined in Section 3.10 of the 4th Edition of the LRFD Manual with the 2008 Interims were followed to characterize the seismic hazard. Note that these procedures use a design earthquake with a return period of 1000 years, or a 7 percent probability of exceedance (PE) in 75 years. This is a departure from previous AASHTO Specifications which used a design earthquake with a return period of 500 years, or a 10 percent PE in 50 years. The USGS interactive deaggregation website (2002) was used to determine the peak ground acceleration and spectral accelerations. The results of the hazard analysis are presented in Table 2.

Table 2. Seismic Parameters for Design Earthquake (7% PE in 75 years).

Site Class (by Soil Type and Profile) C – very dense soil

Horizontal Peak Ground Acceleration (PGA) 0.160 g

Horizontal Response Spectral Acceleration at Period of 0.2 sec (Ss) 0.376 g

Horizontal Response Spectral Acceleration at Period of 1.0 sec (S1) 0.137 g

As 0.192 g

SDS 0.451 g

SD1 0.228 g

Seismic Zone 2

The values in Table 2 were used to develop the 5-percent-damped-design response spectrum shown in Figure 2 below.

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

0.40

0.45

0.50

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0

Period, Tm (seconds)

El as tic S ei sm ic C oe ffi ci en t, C sm

Figure 2. 5-Percent-Damped-Design Response Spectrum.

6.5 Liquefaction

The procedures outlined in Subsection 6.5.2 of the ODOT Geotechnical Design Manual (2008) were generally followed in order to assess the liquefaction potential at the site.

One of the conditions for preliminary screening of liquefaction potential is an assessment of the (N1)60 values in the upper 75 feet of the soil profile. All of the individual layers below the water table had average (N1)60 values greater than 25 blows per foot (bpf).

(N1)60 values greater than 25 bpf is an indicator that the soils are not susceptible to liquefaction and a detailed liquefaction analysis is not necessary.

Several of the individual (N1)60 values in the borings are below 25 bpf, but liquefaction is still not of concern for two reasons: 1) most of the values less than 25 bpf are above the anticipated long-term groundwater table elevation at each site and therefore are not susceptible to liquefaction, and 2) the few values that are less than 25 bpf are widespread throughout the profile, indicating that these values are not representative of specific layers or depths and are more likely to be anomalies related to the presence of cobbles, boulders, and/or discrete pockets of loose materials in the profile. In addition, the use of drilled shaft foundations extending below the scour elevation will mitigate the potential for loss of support due to strength loss in any isolated thin layers during a seismic event.

Based on the foregoing discussion, no additional liquefaction analysis is considered necessary for the Clark Creek bridge foundation materials.

6.6 Preliminary Drilled Shaft Recommendations

The soil layer depths and strength parameters discussed in Section 6.1 were used in drilled shaft design. Drilled shaft diameters of 4, 5, and 6 feet were analyzed for axial capacity provided by both skin friction and end-bearing by the methods recommended in the American Association of State Highway Transportation Officials (AASHTO) Load and Resistance Factor Design (LRFD) Specifications (2008) and in the FHWA drilled shaft design manual (O’Neil and Reese, 1999).

Two drilled shafts are recommended to carry the loads at each abutment. After the final loads are determined, the diameter of the drilled shafts should be the minimum size required to carry the design loads, rounded up to the nearest 0.5 feet.

Charts of axial resistance versus depth for each bent are contained in Appendix G for 4, 5, and 6 foot diameter drilled shafts. The resistance factors listed in Table 10.5.5.2.4-1 of the AASHTO LRFD Specifications (2008) were used to calculate the factored axial resistance shown on the Charts in Appendix G. The resistance factors in the table are for foundations with some redundancy, i.e., at least 2 drilled shafts at each abutment. The capacity for the extreme event limit states were calculated using a resistance factor of 1.0 for both the scour and no scour conditions. Scour should be included in the extreme event limit state only when relevant.

Preliminary drilled shaft recommendations are summarized in Table 3.

The design charts in Apppendix G and the tip elevations listed in Table 3 were not modified to account for the dead load of the drilled shaft above the scour elevation. The load should be included in the design axial loads when using the design charts.

Table 3. Preliminary Drilled Shaft Recommendations.

Abutment 1 Abutment 2

Station at Centerline of Bridge 69+40.00 70+32.00

Finished Bridge Deck Elevation (feet) 4166.380 4161.748

Estimated Top of Drilled Shaft Elevation = Bottom of Pile Cap Elevation (feet) 4157 4153

Design Scour Elevation (feet) 4125 4125

Recommended Uppermost Tip Elevation (feet)

B = 4 ft (2 shafts)

B = 5 ft (2 shafts)

B = 6 ft (2 shafts)

Recommended Lowest Tip Elevation (feet) 4080 4080

NOTES:

B = Drilled Shaft Diameter.

The recommended lowest tip elevation shown on the design charts and in Table 3 was set based on constructability of the drilled shafts and the termination depth of the subsurface investigation borings.

It is assumed that the center-to-center spacing of the drilled shafts at each abutment will be at least 4.0 diameters or more.

6.7 Settlement

The estimated settlement at the top of the drilled shafts due to the working loads listed in Subsection 6.2 (DL + LL) is less than 0.5 inches for the diameters and lengths of drilled shafts presented in Table 3. Charts of settlement versus load are presented in Appendix G following each axial capacity chart. The settlement charts include the design scour and present settlement estimates for both the uppermost and lowest tip elevations listed in Table 3.

6.8 Lateral Analysis

Lateral loads were not provided, but they are anticipated to be significant due to the seismic hazard at the site. Table 4 provides the soil parameters that are recommended for lateral foundation analysis.

Table 4. Recommended Soil Parameters for Lateral Analysis.

Elevation (feet)

Material Description

Moist Unit Weight

(pcf)

Effective Unit Wt.

(pcf)

Friction Angle

(degrees) nh

(ksi/ft)

> 4160 New Fill – Sandy Gravel 130 67.6 34 1.11

4147 – 4160 Sand w/Gravel 120 57.6 32 60

4128 – 4147 Cohesionless

IGM 135 72.6 40 125

4110 – 4128 Sand w/Gravel 130 67.6 37 125

< 4128 Cohesionless

IGM 135 72.4 42 125

NOTES:

1. IGM = Intermediate Geomaterial, term used to describe very dense or hard soils with SPT N-values greater than 50 blows per foot.

2. Effective unit weight is only applicable if the layer is below the water table elevation. See discussion on groundwater levels in Section 3.2.

3. nh is the constant giving the variation of soil modulus with depth in the equation Es = nhz where Es = soil modulus and z = depth below the ground surface (see section 10.4.6.2.4 in AASHTO [2008] for more information).

7. DRILLED SHAFT CONSTRUCTION CONSIDERATIONS

Based on both surface observations of the Clark Creek channel and adjacent flood plain and the subsurface investigation borings, it is anticipated that boulders may be encountered during the drilling and installation of drilled shaft foundations at the bridge site. Boulders that are encountered during shaft installation that impede or prevent advancement of the shaft will have to be removed by such means as drilling, blasting, jack-hammering, hoe-ramming, clam shell extraction, or other methods approved by the Project Engineer.

The soils encountered in the borings will cave if excavated with an open hole. Full depth temporary casing or drilling slurry must be used to protect the side walls of the drilled shaft excavation during construction. The drilled shaft design includes a significant amount of skin friction along the sides of the drilled shaft. Therefore, any temporary casing must be removed from the completed drilled shaft. Very permeable layers of coarse gravel, cobbles and boulders are likely to be encountered which may exclude the use of drilling slurry. The contractor should seriously consider the subsurface conditions when choosing the method of drilled shaft construction.

Wet methods of construction will be necessary. An adequate head of water (casing method) or drilling slurry should be maintained inside of the drilled shaft excavation to prevent heaving of the soils at the bottom of the excavation.

Cross-hole Sonic Logging (CSL) should be completed on each drilled shaft to insure the integrity of the drilled shaft. Each rebar cages should include at least one CSL access tube per foot diameter of drilled shaft (i.e., at least four CSL access tubes for an four-foot diameter drilled shaft). The access tubes should be spaced evenly on the rebar cage and securely fastened to either the inside or outside of the cage.

The WFLHD Geotechnical Team should be part of the reviewing effort of the contractor’s drilled shaft submittals to evaluate appropriateness of the proposed construction based on the subsurface conditions. A WFLHD geotechnical engineer or engineering geologist should also be present on site during excavation of the drilled shafts to verify that the subsurface conditions are consistent with the conditions represented in this report. Subsurface conditions that are significantly different than those for which the drilled shafts were designed could result in the need to modify the shaft bottom elevation or result in other design changes.

8. APPROACH EMBANKMENTS AND ABUTMENT WALL DESIGN

The approach embankment will likely be constructed with nearby material deposited at the White River Bridge site during the 2006 debris flow event consisting of gravelly sand and cobbles or with shot rock material from a nearby Forest Service quarry. These materials are adequate for use as backfill and fill behind abutments and wing walls;

however, the material should be screened with a grizzly or by other means to remove particles greater than 6 inches in size. A perforated corrugated polyethylene drain should be installed behind walls to ensure drainage. The soil parameters listed in Table 5 may be used to determine the lateral earth pressures exerted on the abutment walls and wing walls.

Table 5. Recommended Soil Parameters for Abutment Wall Design.

Parameter Design Value* Moist Unit Weight 130 pcf

Angle of Internal Friction 34 degrees

Active Earth Pressure Coefficient, Ka 0.28

Active Equivalent Fluid Pressure 36 psf/ft

At-Rest Earth Pressure Coefficient, K0 0.44

At-Rest Equivalent Fluid Pressure 57 psf/ft

Passive Earth Pressure Coefficient, Kp 3.54

Passive Equivalent Fluid Pressure 460 psf/ft

Wall-Backfill Interface Friction Angle, δ 26 degrees

*Design values based on a drained condition behind the wall.

The above values do not include factors of safety or load factors. Appropriate factors of safety or load factors should be used with these parameters. It is generally assumed that compacted backfill creates at-rest lateral earth pressure behind unyielding walls and that a slight movement at the top of the wall (0.002 x wall height) creates active lateral earth pressures behind walls. Passive lateral earth pressures are applicable when the wall is pushed back towards the retained soil mass and wall movements of 0.02 x wall height at the top of the wall are necessary to reach the passive earth pressures listed above.

The procedures outlined in Appendix A11 of LRFD (2008) should be used to determine the seismic forces exerted on the walls. Once the wall geometry is determined, the Geotechnical Team can assist in development of the seismic active pressure.

Embankments constructed with these materials can safely be constructed as steep as 1V:1.5H. However, embankments constructed 1V:2H or steeper with the nearby sandy gravel material will be highly susceptible to erosion and shallow failures during spring thaw and periods of heavy precipitation. Embankment protection (riprap or shot-rock) or aggressive revegetation and erosion control will be needed to protect slopes 1V:2H or steeper.

9. USE OF THIS REPORT

Professional judgments and recommendations are presented in this report. They are based partly on evaluation of the technical information gathered, partly on historical reports and partly on the WFLHD Geotechnical Team’s general experience with subsurface conditions in the area. It should be noted the borings might not represent potentially unfavorable subsurface conditions between borings. If, during construction, soil conditions are encountered that vary from those discussed in this report or historical reports, or if design loads and/or configurations change, the Geotechnical Team should be notified immediately in order that it may evaluate effects, if any, on foundation performance.

This report provides preliminary foundation recommendations for initial bridge design based on preliminary loading information. A final report containing finalized foundation recommendations will be provided to the WFLHD Structures Section once the bridge design process has begun and the actual bridge geometry and design loads of the new structures have been determined.

For questions regarding this report, please contact WFLHD Engineering Geologist Dave Lofgren at 360-619-7706 (david.lofgren@fhwa.dot.gov) or WFLHD Geotechnical Engineer Brian Collins at 360-619-7657 (brian.collins@fhwa.dot.gov).

10. REFERENCES

AASHTO LRFD Bridge Design Specifications 2008 Interim Revisions (2008) American Association of State Highway and Transportation Officials, Washington, D.C.

ODOT Geotechnical Design Manual (2008) Oregon Department of Transportation, Technical Services Branch, Geo-Environmental Section, 325 p.

O’Oneil, M. W., and Reese, L. C. (1999) Drilled Shafts: Construction Procedures and Design Methods, FHWA Report No. FHWA-IF-99-025, Federal Highway Administration, Washington, D.C., 758 p.

U.S. Geological Survey, USGS Earthquake Hazards Program website, 2002 Interactive Deaggregations, http://eqint.cr.usgs.gov/deaggint/2002/index.php, accessed August 4, 2008. Draf

APPENDIX A

Boring Location Map

16-DEC-200F:\CAD_Ser

PROJECTSTATE

CC-1

CC-2

C L A

R K

C R E E K

SHEET

NUMBER

--/---- Checked by: --/---- Designed by:

N 88%%d 38’ 07" E

BEGIN BRIDGE

LC

LC

END BRIDGE

Sta. 70+42.00

El. 4166.67

Bridge @

Rdwy

Sta. 69+32.00

El. 4172.139 F lo w

N

CLARK CREEK

BRIDGE INVESTIGATION

BORING LOCATIONS

APPENDIX B

Boring Logs CC-1 and CC-2

R-9

Silty fine SAND with trace of pea gravel and organic matter, brown, moist.

30.0

26.5

25.0

20.3

R-2

S-8

R-8

S-7

R-7

S-6

R-6

S-5

R-5

S-4

R-4

S-3

S-2

15.0

S-1

R-1

R-3

18-27-24 (Rec: 6in)

50/4 (Rec: 1in)

16-44-31 (Rec: 6in)

50/0.5 (Rec: 0in)

38-50/5.5 (Rec: 5in)

3-2-7 (Rec: 13in)

3-5-7 (Rec: 7in)

3-1-2 (Rec: 5in)

20.0

Well graded gravelly silty SAND, very dense, wet, gray to brown, gravel subangular to subrounded to 1½"

GRAVEL, gray.

Fine to medium silty SAND with a trace of gravel, very dense, wet, brown to gray.

No Recovery

Silty sandy GRAVEL, very dense, wet, gray, trace of wood fragments.

Silty SAND grading to sandy SILT, loose, moist, brown to gray, layers of organic matter.

Silty fine SAND, medium dense, moist, brown, layers of organic matter.

13.1 13.0

11.0

10.0 9.5

8.0

6.5

5.0 4.5

3.0

16.5

RQD (%)

D E

P

TH

(f t)

51 mm O.D. SPLIT TUBE SAMPLE (SPT)

PLASTIC LIMIT

DESCRIPTION

BORING CC-1

Highway 35 Betterment

RECOVERY (%)

WATER LEVEL

Sheet 1 of 3

HQ CORE

HW Casing AdvancerBORING LOG (English Units)

STANDARD BLOWS PER FOOT

(140 lb mass, 30 in drop)

LIQUID LIMIT

WEATHER:

SAMPLE PENETRATION RESISTANCE

10/20/086 in H-S AUGER

60G R

A P

H

IC

L O

G

OTHER:

83 mm O.D. SPLIT TUBE SAMPLE (D & M)

Haz-Tech, Mike Corn

Clark Creek, Sta 69+44, 20 ft RT

D E

P

TH

(f t)

4156.00 0

S A

M P

LE

CME-850

CORE

AUGER

PROJECT:

NQ CORE

8 in H-S AUGER

WATER CONTENT (%)

DRILLER:

BEGAN:

DRILL:

COMPLETED:

Partly Cloudy Windy

STATION, OFFSET:

BLOW

10/20/08

COUNT

76 mm SHELBY TUBE

ELEV:

S A

M P

LE

44 mm O.D. SPLIT TUBE SAMPLE 100

FEDERAL HIGHWAY ADMINISTRATION

VANCOUVER, WASHINGTON

GEOTECHNICAL SECTION

S-9

S-10

R-11

CME-850

CORE

AUGER

PROJECT:

NQ CORE

R-10

8 in H-S AUGER

R-15

S-14

R-14

R-13

Fine to medium sandy SILT with a trace of gravel, medium dense, wet, gray.

R-12

S-11

38-50/5 (Rec: 7in)

50/4½ (Rec: 3in)

30-25-39 (Rec: 12in)

30-20-16 (Rec: 12in)

1-1-1 (Rec: 13in)

Well graded silty sandy GRAVEL with some gravel fragments, very dense, wet, brownish gray.

Gravel fragments with fine to coarse silty SAND, very dense, wet, gray.

Fine to medium silty SAND with gravel fragments, very dense, wet, gray.

Fine silty SAND with a trace of gravel, dense, wet, mostly gray with rusty brown streaks.

Fine to medium sandy SILT with a trace of gravel to ¾", loose, wet, gray brown with rusty streaks.

6-4-8 (Rec: 16in)

36.5

60.0

55.9

55.0

50.3 50.0

46.5

45.0

40.0

S-13

35.0

31.5

41.5

BEGAN:

S-12

Haz-Tech, Mike Corn

RQD (%)

Clark Creek, Sta 69+44, 20 ft RT

HW Casing Advancer

Sheet 2 of 3

RECOVERY (%)

OTHER:

BLOW

G R

A P

H

IC

L O

G

BORING CC-1

DESCRIPTION

WATER LEVEL

10/20/08

WEATHER:

D E

P

TH

(f t)

STANDARD BLOWS PER FOOT

(140 lb mass, 30 in drop)S

A M

P

LE

BORING LOG (English Units)

LIQUID LIMIT

SAMPLE PENETRATION RESISTANCE

STATION, OFFSET:

DRILL:

Partly Cloudy Windy

COMPLETED:

10076 mm SHELBY TUBE

10/20/08

COUNT

DRILLER:

S A

M P

LE

WATER CONTENT (%)

6 in H-S AUGERFEDERAL HIGHWAY ADMINISTRATION

VANCOUVER, WASHINGTON

GEOTECHNICAL SECTION

44 mm O.D. SPLIT TUBE SAMPLE

83 mm O.D. SPLIT TUBE SAMPLE (D & M)

Highway 35 Betterment

HQ CORE

D E

P

TH

(f t)

PLASTIC LIMIT

51 mm O.D. SPLIT TUBE SAMPLE (SPT)

R-19

S-18

R-18

S-17

R-17

S-16

R-16

S-15

AUGER

S A

M P

LE

WATER CONTENT (%)

Haz-Tech, Mike Corn

CME-850

S-19

CORE

NQ CORE

Silty sandy GRAVEL with gravel fragments, very dense, wet, gray.

8 in H-S AUGER

50/3 (Rec: 0in)

39-31-28 (Rec: 11in)

50/3 (Rec: 0in)

50/4 (Rec: 1in)

Boring terminated at a depth of 80 Feet 3 Inches

GRAVEL and coarse SAND, very dense, wet, gray/rusty. (No sample kept.)

Gravelly silty SAND, very dense, wet, gray/brownish gray with some red gravel.

Gravel fragments, very dense, wet, gray. (No sample kept.)

GRAVEL and coarse SAND, very dense, wet, gray/rusty.

39-50/5 (Rec: 8in)

75.0

80.3

76.5

PROJECT:

70.3 70.0

65.3 65.0

60.9

80.0

BLOW LIQUID LIMIT

Partly Cloudy Windy

BEGAN:

COUNT

SAMPLE PENETRATION RESISTANCE

FEDERAL HIGHWAY ADMINISTRATION

VANCOUVER, WASHINGTON

GEOTECHNICAL SECTION

44 mm O.D. SPLIT TUBE SAMPLE

D E

P

TH

(f t)

S A

M P

LE

DESCRIPTION

Sheet 3 of 3

WATER LEVEL

RECOVERY (%)

RQD (%)

BORING CC-1

10/20/08

WEATHER:

STANDARD BLOWS PER FOOT

(140 lb mass, 30 in drop)

Clark Creek, Sta 69+44, 20 ft RT

BORING LOG (English Units)

10050

HQ CORE DRILLER:

DRILL:

COMPLETED:

76 mm SHELBY TUBE

10/20/08

STATION, OFFSET:

HW Casing Advancer

G R

A P

H

IC

L O

G

OTHER:

83 mm O.D. SPLIT TUBE SAMPLE (D & M)

Highway 35 Betterment

6 in H-S AUGER

D E

P

TH

(f t)

51 mm O.D. SPLIT TUBE SAMPLE (SPT)

PLASTIC LIMIT

16.0

29.5

26.0

24.5

21.0

R-9

S-1

S-8

R-8

S-7

R-7

S-6

R-6

S-5

R-5

S-4

R-4

S-3

S-2

14.5

R-1

GRAVEL fragments first 5" trending to silty fine-medium SAND with traces of gravel to 1½", dense, dry, brownish gray/gray.

R-3

19.5

21-16-17 (Rec: 8in)

21-40-42 (Rec: 6in)

43-15-15 (Rec: 8in)

7-16-22 (Rec: 11in)

50/4 (Rec: 3in)

40-16-12 (Rec: 11in)

42-39-43 (Rec: 11in)

GRAVEL fragments trending to gravelly silty SAND with gravel

Silty sandy GRAVEL to 1½", very dense, wet, black/rust/gray.

Sandy GRAVEL to 1½" , very dense, wet, dark gray.

Silty sandy GRAVEL, dense, wet, mostly gray/brown. Gravel to 1½".

Silty sandy GRAVEL, very dense, wet, brownish gray. Gravel to 1".

GRAVEL fragments first 3" trending to silty sandy GRAVEL, medium dense, wet, brown. Gravel to 1".

Fine SAND with a trace of gravel to 1", dense, wet, brownish gray.

Fine SAND with a trace of gravel to ½", very dense, moist, gray/rusty gray.

14.0

12.5

11.0

9.5 9.0

7.5

4.8 4.5

3.0

5-12-48 (Rec: 12in)

RECOVERY (%)

Clark Creek, Sta 70+37, 16 ft RT

D E

P

TH

(f t)

51 mm O.D. SPLIT TUBE SAMPLE (SPT)

PLASTIC LIMIT

DESCRIPTION

BORING CC-2

Highway 35 Betterment

WATER LEVEL

Sheet 1 of 3

D E

P

TH

(f t)

RQD (%)

HW Casing AdvancerBORING LOG (English Units)

STANDARD BLOWS PER FOOT

(140 lb mass, 30 in drop)

LIQUID LIMIT

SAMPLE PENETRATION RESISTANCE

WEATHER:

6 in H-S AUGER

G R

A P

H

IC

L O

G

OTHER:

83 mm O.D. SPLIT TUBE SAMPLE (D & M)

10/21/08

CME-850

HQ CORE

STATION, OFFSET:

4153.50 0

S A

M P

LE

WATER CONTENT (%)

Haz-Tech, Mike Corn

CORE

AUGER

PROJECT:

NQ CORE

8 in H-S AUGER

COUNT

BEGAN:

DRILLER:

DRILL:

Sunny Chilly ½" snow on ground

COMPLETED:

S A

M P

LE

44 mm O.D. SPLIT TUBE SAMPLE

10/21/08

FEDERAL HIGHWAY ADMINISTRATION

VANCOUVER, WASHINGTON

GEOTECHNICAL SECTION

ELEV:

BLOW

76 mm SHELBY TUBE

R-10

S-10

CORE

AUGER

PROJECT:

NQ CORE

S-9 30

R-15

S-14

R-14

S-13

S-12 to ¾", dense, wet, gray.

S-11

R-11

8 in H-S AUGER

23-24-17 (Rec: 13in)

25/0 (Rec: 0in)

50/4.5 (Rec: 1in)

18-26-29 (Rec: 13in)

18-32-26 (Rec: 14in)

21-18-13 (Rec: 6in)

Silty fine SAND with pieces of gravel to ¾", very dense, wet, Gravelly silty SAND with gravel to ¾", dense, wet, gray.

Refusal

A few GRAVEL fragments. No sample kept.

Silty sandy GRAVEL to 1½", very dense, wet, gray.

Gravelly silty SAND with gravel fragments, gravel to 1½", very dense, wet, gray.

34.5

59.5

56.0

54.5

49.6 49.5

44.8 44.5

41.0

36.0

R-13

31.0

39.5

BLOW

D E

P

TH

(f t)

R-12

CME-850

G R

A P

H

IC

L O

G

RQD (%)

Sheet 2 of 3

HW Casing Advancer

BEGAN:

OTHER:

Clark Creek, Sta 70+37, 16 ft RT

RECOVERY (%)

BORING CC-2

DESCRIPTION

10/21/08

WATER LEVEL

WEATHER:

STANDARD BLOWS PER FOOT

(140 lb mass, 30 in drop)S

A M

P

LE

BORING LOG (English Units)

LIQUID LIMIT

SAMPLE PENETRATION RESISTANCE

DRILL:

Sunny Chilly ½" snow on ground

COMPLETED:

10076 mm SHELBY TUBE

10/21/08

STATION, OFFSET:

DRILLER:

S A

M P

LE

WATER CONTENT (%)

Haz-Tech, Mike Corn

6 in H-S AUGER

COUNT

FEDERAL HIGHWAY ADMINISTRATION

VANCOUVER, WASHINGTON

GEOTECHNICAL SECTION

83 mm O.D. SPLIT TUBE SAMPLE (D & M)

44 mm O.D. SPLIT TUBE SAMPLE

Highway 35 Betterment

HQ CORE

D E

P

TH

(f t)

51 mm O.D. SPLIT TUBE SAMPLE (SPT)

20 40

PLASTIC LIMIT

R-19

S-18

R-8

S-17

R-17

S-16

R-16

S-15

AUGER

S A

M P

LE

WATER CONTENT (%)

Haz-Tech, Mike Corn

CME-850

S-19

CORE

NQ CORE

gray.

8 in H-S AUGER

47-50/4.5 (Rec: 6in)

17-50/4 (Rec: 6in)

27-30-20/0 (Rec: 10in)

10-10-19 (Rec: 12in)

Boring Terminated at a Depth of 80 Feet 6 Inches.

Gravelly silty fine-medium SAND, very dense, wet, brownish gray.

Fine silty SAND, very dense, wet, gray.

Fine silty SAND with a few pieces of gravel to 1", very dense, wet, gray with rusty zone ~ 1".

Fine SAND with pieces of gravel to ½" and a trace of silt, medium dense, wet, mostly gray with rusty streaks.

34-48-33 (Rec: 12in)

74.5

80.5

75.3

PROJECT:

70.5

69.5

66.0

64.5

61.0

79.5

BLOW LIQUID LIMIT

Sunny Chilly ½" snow on ground

BEGAN:

COUNT

SAMPLE PENETRATION RESISTANCE

FEDERAL HIGHWAY ADMINISTRATION

VANCOUVER, WASHINGTON

GEOTECHNICAL SECTION

44 mm O.D. SPLIT TUBE SAMPLE

D E

P

TH

(f t)

S A

M P

LE

DESCRIPTION

Sheet 3 of 3

WATER LEVEL

RECOVERY (%)

RQD (%)

BORING CC-2

10/21/08

WEATHER:

STANDARD BLOWS PER FOOT

(140 lb mass, 30 in drop)

Clark Creek, Sta 70+37, 16 ft RT

BORING LOG (English Units)

10050

HQ CORE DRILLER:

DRILL:

COMPLETED:

76 mm SHELBY TUBE

10/21/08

STATION, OFFSET:

HW Casing Advancer

G R

A P

H

IC

L O

G

OTHER:

83 mm O.D. SPLIT TUBE SAMPLE (D & M)

Highway 35 Betterment

6 in H-S AUGER

D E

P

TH

(f t)

51 mm O.D. SPLIT TUBE SAMPLE (SPT)

PLASTIC LIMIT

APPENDIX C

Unified Soil Classification System

APPENDIX D

Laboratory Test Reports

APPENDIX E

Clark Creek Graphical Boring Logs

U. S. DEPARTMENT OF TRANSPORATION

FEDERAL HIGHWAY ADMINISTRATION

R

D

E C

F

C A

D

S e r h e c k e d b y

D s ig n e d b

R

E

N

O R

A I

N

N

S T F

R

I

D

D E

P A

T

N T O F T A

SP

T T

O

U T

E

A T E S O

A M E

R I C

A

M

N

88/11"

50/0"

50/4"

50/4.5

88 /11"

88 /11"

50/4"

50/3"

50/3"

0-10’

10-25’

25-40’

40-80’

Very dense, wet, gravelly silty sand or sandy gravel.

Drilled extremely slow in possible boulders to rough, smooth, and fast.

Loose to med. dense, damp to moist, brown, silty fine sand. Soft to smooth drilling.

Very dense, wet, gravelly silt and sand or silty sandy gravel. Drilled generally smooth and med. fast to occasionally rough and bumpy.

NOTE:

OR FS ERFO 2007(1)-11(2)

CLARK CR. BRIDGE

BORING CC-1, ELEVATION 4156 FT.

Very loose to med. dense, wet, fine to med.

sandy silt or silty sand with a few pieces of gravel. Drilled med. speed and smooth to very fast.

1.

N1

Lab - Tested samples consisted of SM (Silty sand and silty sand with gravel) and SP-SM (Poorly graded sand with silt and gravel). See Section 4 and Appendix B.

U. S. DEPARTMENT OF TRANSPORATION

FEDERAL HIGHWAY ADMINISTRATION

0-80’

50/4"

D

E C

F

C A

D

S r h e c k e d b

D s ig n e d b

R

E

N

O R

A I

N

N

S T F

R

I

D

D E

P A

T

N T O F T A

SP

T T

O

U T

E

A T E S O

A M E

R I C

A

M

N

25/0’

50/10"

50/4.5"

50/4"

50/4.5"

R

(R=Refusal)

NOTE:

1.

N1 60

OR FS ERFO 2007(1)-11(2)

CLARK CR. BRIDGE

BORING CC-2, ELEVATION 4153.5 FT

Lab - tested samples consisted of SM (Silty sand);

SP-SM (Poorly graded sand with silt and gravel);

SW-SM (Well graded sand with silt and gravel);

and GP-GM (Poorly graded gravel with silt and sand). See Section 4 and Appendix B.

Entire boring is med. dense to very dense, generally wet, silty, fine to med. and coarse sand with gravel & probable cobbles and boulders.

The zone from 70-80’ is denser than the zone from 0-70’.

APPENDIX F

SPT N-Value Correction Spreadsheets

CORRECTIONS FOR STANDARD PENETRATION TEST (SPT)

B. Collins updated 1-Nov-08 Reference: AASHTO LRFD Bridge Design Specifications, 4th Edition, 2007 with 2008 Interim Revisions

Subsection 10.4.6.2.4, Drained Strength of Granular Soils Calculations:

N = uncorrected SPT blowcount (blows/foot) N1 = SPT blow count corrected for overburden pressure (blows/foot)

N1 = CN N

CN = [0.77 log10 (40/σ'v)], and CN < 2.0 σv' = vertical effective stress N60 = SPT blow count corrected for hammer efficiency (blows/foot)

N60 = (ER / 60%) N

ER = hammer efficiency expressed as % of theoretical free fall energy delivered by the hammer system ER typically 80% for automatic trip hammer ER typically 60% for drop hammer using rope and cathead N160 = SPT blow count corrected for both overburden effects and hammer efficiency effects

N160 = CN N60

Project: Clark Creek Bridge Boring No.: CC-1

ER for hammer system used = 80 % Average total unit weight of soil = 130 lb/ft3

Ground surface elevation = 4156 ft Water depth = 10.0 ft

Depth, ft N Elev. (ft) σv (psf) σv' (psf) CN N1 ER/60% N60 N160

3.0 3 4153.0 390 390 1.55 5 1.33 4 6

5.0 12 4151.0 650 650 1.38 17 1.33 16 22

8.0 9 4148.0 1040 1040 1.22 11 1.33 12 15

10.0 88 4146.0 1300 1300 1.15 101 1.33 100 100

13.0 R 4143.0 1690 1503 1.10 R 1.33 100 100

15.0 75 4141.0 1950 1638 1.07 80 1.33 100 100

20.0 R 4136.0 2600 1976 1.01 R 1.33 100 100

25.0 56 4131.0 3250 2314 0.95 53 1.33 75 71

30.0 12 4126.0 3900 2652 0.91 11 1.33 16 15

35.0 2 4121.0 4550 2990 0.87 2 1.33 3 2

40.0 36 4116.0 5200 3328 0.83 30 1.33 48 40

45.0 64 4111.0 5850 3666 0.80 51 1.33 85 68

50.0 R 4106.0 6500 4004 0.77 R 1.33 100 100

55.0 88 4101.0 7150 4342 0.74 65 1.33 100 100

60.0 89 4096.0 7800 4680 0.72 64 1.33 100 100

65.0 R 4091.0 8450 5018 0.69 R 1.33 100 100

70.0 R 4086.0 9100 5356 0.67 R 1.33 100 100

75.0 59 4081.0 9750 5694 0.65 38 1.33 79 51

80.0 R 4076.0 10400 6032 0.63 R 1.33 100 100Draf

CORRECTIONS FOR STANDARD PENETRATION TEST (SPT)

B. Collins updated 1-Nov-08 Reference: AASHTO LRFD Bridge Design Specifications, 4th Edition, 2007 with 2008 Interim Revisions

Subsection 10.4.6.2.4, Drained Strength of Granular Soils Calculations:

N = uncorrected SPT blowcount (blows/foot) N1 = SPT blow count corrected for overburden pressure (blows/foot)

N1 = CN N

CN = [0.77 log10 (40/σ'v)], and CN < 2.0 σv' = vertical effective stress N60 = SPT blow count corrected for hammer efficiency (blows/foot)

N60 = (ER / 60%) N

ER = hammer efficiency expressed as % of theoretical free fall energy delivered by the hammer system ER typically 80% for automatic trip hammer ER typically 60% for drop hammer using rope and cathead N160 = SPT blow count corrected for both overburden effects and hammer efficiency effects

N160 = CN N60

Project: Clark Creek Bridge Boring No.: CC-2

ER for hammer system used = 80 % Average total unit weight of soil = 130 lb/ft3

Ground surface elevation = 4153.5 ft Water depth = 10.0 ft

Depth, ft N Elev. (ft) σv (psf) σv' (psf) CN N1 ER/60% N60 N160

3.0 28 4150.5 390 390 1.55 43 1.33 37 58

4.5 150 4149.0 585 585 1.41 212 1.33 100 100

7.5 38 4146.0 975 975 1.24 47 1.33 51 63

9.5 30 4144.0 1235 1235 1.16 35 1.33 40 47

12.5 82 4141.0 1625 1469 1.10 91 1.33 100 100

14.5 33 4139.0 1885 1604 1.08 35 1.33 44 47

19.5 60 4134.0 2535 1942 1.01 61 1.33 80 81

24.5 82 4129.0 3185 2280 0.96 79 1.33 100 100

29.5 31 4124.0 3835 2618 0.91 28 1.33 41 38

34.5 58 4119.0 4485 2956 0.87 51 1.33 77 67

39.5 55 4114.0 5135 3294 0.83 46 1.33 73 61

44.4 120 4109.1 5772 3625 0.80 96 1.33 100 100

49.5 R 4104.0 6435 3970 0.77 R 1.33 100 100

54.5 41 4099.0 7085 4308 0.75 31 1.33 55 41

59.5 81 4094.0 7735 4646 0.72 58 1.33 100 78

64.5 29 4089.0 8385 4984 0.70 20 1.33 39 27

69.5 R 4084.0 9035 5322 0.67 R 1.33 100 100

74.5 150 4079.0 9685 5660 0.65 98 1.33 100 100

79.5 167 4074.0 10335 5998 0.63 106 1.33 100 100Draf

APPENDIX G

Drilled Shaft Design Charts – Axial Capacity and Settlement

Bent ID: Clark Creek Abutment 1 & 2 Ground surface elevation = 4162 ft Diameter of drilled shaft = 4.0 ft

Top of drilled shaft elevation = 4153 ft Shaft cross-sectional area = 12.6 sq ft Design scour elevation = 4125 ft Shaft circumference = 12.6 ft

LRFD factored axial resistance determined using resistance factors in Table 10.5.5.2.4-1 of AASHTO (2008)

CLARK CREEK BRIDGE -- DRILLED SHAFT DESIGN CHART

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

Capacity (kips)

El ev at io n (fe et

Nominal (Ultimate) Axial Resistance - no scour condition (resistance factor = 1.0, extreme event limit state)

Nominal (Ultimate) Axial Resistance - scour condition (resistance factor = 1.0, service and extreme event limit state)

LRFD Factored Axial Resistance - scour condition - (strength limit state resistance factors) - MULTIPLE SHAFT BENT

Uppermost Tip Elevation

Lowest Tip Elevation

LOAD - SETTLEMENT DIAGRAM

ABUTMENT 1 and ABUTMENT 2 CLARK CREEK BRIDGE

OR FS ERFO 2007(1)-11(1)

DRILLED SHAFT DIAMETER = 4 ft

GROUND SURFACE (SCOUR) ELEVATION = 4125 ft

0.0

0.5

1.0

1.5

2.0

2.5

3.0

0 500 1000 1500 2000 2500 3000

Load (kips)

Se ttl em en t ( in ch es

Tip elevation = 4098

Tip elevation = 4080Draf

Ground surface elevation = 4162 ft Diameter of drilled shaft = 5.0 ft

Top of drilled shaft elevation = 4153 ft Shaft cross-sectional area = 19.6 sq ft Design scour elevation = 4125 ft Shaft circumference = 15.7 ft

LRFD factored axial resistance determined using resistance factors in Table 10.5.5.2.4-1 of AASHTO (2008)

CLARK CREEK BRIDGE -- DRILLED SHAFT DESIGN CHART

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

Capacity (kips)

El ev at io n (fe et

Nominal (Ultimate) Axial Resistance - no scour condition (resistance factor = 1.0, extreme event limit state)

Nominal (Ultimate) Axial Resistance - scour condition (resistance factor = 1.0, service and extreme event limit state)

LRFD Factored Axial Resistance - scour condition - (strength limit state resistance factors) - MULTIPLE SHAFT BENT

Uppermost Tip Elevation

Lowest Tip Elevation

OR FS ERFO 2007(1)-11(1)

DRILLED SHAFT DIAMETER = 5 ft

GROUND SURFACE (SCOUR) ELEVATION = 4125 ft

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

0 500 1000 1500 2000 2500 3000 3500 4000

Load (kips)

Se ttl em en t ( in ch es

Tip elevation = 4106

Ground surface elevation = 4162 ft Diameter of drilled shaft = 6.0 ft

Top of drilled shaft elevation = 4153 ft Shaft cross-sectional area = 28.3 sq ft Design scour elevation = 4125 ft Shaft circumference = 18.8 ft

LRFD factored axial resistance determined using resistance factors in Table 10.5.5.2.4-1 of AASHTO (2008)

CLARK CREEK BRIDGE -- DRILLED SHAFT DESIGN CHART

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

Capacity (kips)

El ev at io n (fe et

Nominal (Ultimate) Axial Resistance - no scour condition (resistance factor = 1.0, extreme event limit state)

Nominal (Ultimate) Axial Resistance - scour condition (resistance factor = 1.0, service and extreme event limit state)

LRFD Factored Axial Resistance - scour condition - (strength limit state resistance factors) - SINGLE SHAFT BENT

Uppermost Tip Elevation

Lowest Tip Elevation

OR FS ERFO 2007(1)-11(1)

DRILLED SHAFT DIAMETER = 6 ft

GROUND SURFACE (SCOUR) ELEVATION = 4125 ft

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000

Load (kips)

Se ttl em en t ( in ch es

Tip elevation = 4108

END GEOTECHNICAL REPORT