GR18-15_Fall_Creek_Bridge,_Final_Foundation_and_Geotech_Rpt.pdf

Geotechnical Report No. 18-15

Fall Creek Bridge Replacement

Final Foundation and Geotechnical Report

OR PFH 46(13)

Deschutes National Forest, Oregon

December 2015

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Table of Contents 1 Introduction

1.1 Project Location

1.2 Project Description

2 Physical Setting and Geology

2.1 Topography

2.2 Geologic Mapping

2.3 Geologic Hazards

2.4 Climate Data

3 Subsurface Information

3.1 Subsurface Investigation

3.2 Subsurface Profile

3.3 Groundwater Observations

4 Seismicity

4.1 Site Seismicity

4.2 Liquefaction

5 Foundation Recommendations

5.1 Bridge Foundations Considerations

5.2 Scour

5.3 Bridge Layout

5.4 Design Loads

5.5 Driven Piling Recommendations

5.5.1 Pile Type

5.5.2 Pile Group Configuration

5.5.3 Axial Capacities

5.5.4 Pile Setup

5.5.5 Dynamic Pile Load Tests

5.5.6 Settlement

5.5.7 Lateral Analysis

5.6 Wing Walls

6 Earthwork Recommendations

6.1 Cut and Fill Slopes

6.2 Subexcavation

6.3 On-Site Materials and Construction Considerations

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6.4 Dewatering

7 Limitations

8 References

List of Figures Figure 1.1-1. Fall Creek Bridge Replacement Project Location Maps

Figure 1.1-2. Fall Creek Bridge Replacement Topographic and Stationing Maps

List of Tables Table 2.3-1. Mapped Risks for Geologic Hazards

Table 2.4-1. Period of Record Monthly Climate Summary for Sunriver, OR (358246)

Table 2.4-2. Period of Record Monthly Climate Summary for Wikiup Dam, OR (359316)

Table 5.4-1. Structural Design Loads

Table 5.5-1. Recommended Soil parameters for Lateral Analysis

Table 5.6-1. Recommended Soil Parameters for Abutment Wall Design

Appendices

APPENDIX A Site Photographs

APPENDIX B Boring Location Maps

APPENDIX C Unified Soil Classification System

Soil Descriptive Terminology

Boring Logs

APPENDIX D Lab Test Reports

APPENDIX E Design Axial Geotechnical Resistance Charts

Liquefaction Analyses Results

APPENDIX F GR08-15 Seismic Site Response Analysis report

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Figure 1.1-1. Fall Creek Bridge Replacement Project Location Maps

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Figure 1.1-2. Fall Creek Bridge Replacement Topographic and Stationing Maps

Site

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1 Introduction

This report provides geotechnical investigation results, analysis, foundation recommendations, and earthwork recommendations for the proposed Fall Creek Bridge replacement project. The project stationing referenced in this report is from the 70% Bridge Plan Set, dated November 17, 2015.

Subsurface investigation borings were completed by the Oregon Department of Transportation (ODOT) on behalf of Western Federal Lands Highway Divisions (WFLHD). Boring logs were prepared by an

ODOT drilling inspector and reviewed by Curtis Ehlers, Geology Team Leader of ODOT Region 4. Lab test results on select samples were performed at the WFLHD Materials Laboratory. All other geotechnical engineering analyses in this report were performed by WFLHD.

All information and recommendations in this report supersede the information and recommendations presented in WFLHD Geotechnical Memorandum 24-14 (GM 24-14), dated February 2015.

1.1 Project Location

The Fall Creek Bridge is located on Cascades Lakes Highway at MP 26.52 approximately 25 miles west of Bend, Oregon in Deschutes County and Deschutes National Forest as shown on the maps in Figures 1-

1 and 1-2. The coordinates for the bridge are approximately latitude 44.030104° North by 121.738405°

West.

Cascade Lakes Highway is a heavily used route relied upon by commercial traffic and recreationists to access the Deschutes National Forest and the high Cascade lakes and wilderness areas. Several resorts at

Elk Lake, Lava Lake, Cultus Lake, and Crane Prairie Reservoir are accessed by this route. Cascade Lakes

Highway also provides access to 17 trailheads serving the Central Oregon Cascades and over 30 campgrounds and day-use sites around the lakes and reservoirs and along the upper Deschutes River; it is also the access route for numerous privately owned recreational homes on leased National Forest land around Elk Lake.

Traffic volume is estimated to be 567 ADT with SADT peaks approaching 1,000. Vehicle types using the road approaches the full suite of vehicle types found on state highways, including all forms of recreational

(single vehicle, campers, motor homes, motor tour buses, etc.) and commercial traffic (log trucks, belly dumps, lowboys, etc.). Portions of the road are also used as a race course for the Cascade Cycling Classic held in Bend every summer. This is a professional bicycle race that draws competitors from all over the

United States and Europe.

Cascade Lakes Highway, in the area of Fall Creek Bridge, is not plowed in the winter and is therefore closed to vehicular traffic. Specific closure dates depend on weather and snow conditions but typically include the months of November through April.

1.2 Project Description

The existing bridge over Fall Creek is a three span, timber girder structure on what appears to be timber piling foundations. The existing structure is approximately 58 feet in length with limited freeboard above the water surface. Photographs of the site are included in Appendix A of this report.

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The proposed project involves replacing the existing bridge with a single span, voided concrete slab structure approximately 65 feet in length. The proposed bridge will be located on the same alignment.

The roadway grade and bridge deck elevation will be raised by approximately 3 feet to allow for additional flow volume beneath the structure.

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2 Physical Setting and Geology

The following sections summarize the topography, geologic mapping, geologic hazard mapping, and climate data for the project site.

2.1 Topography

The project site is located in a relatively flat area at the north end of Sparks Lake, where Fall Creek, Goose Creek, and Soda Creek flow down from the southern flanks of South Sister and Broken Top mountains (see Figure 1.1-2). According to O’Grady (2015), Sparks Lake was formed when lavas from the Mt. Bachelor Volcanic Chain blocked drainages in the upper Deschutes River basin. Most of the eruptive activity associated with this volcanic chain occurred in four episodes between about 18,000 and

8,000 years ago; Sparks Lake was probably dammed by flows late in this sequence. The basin has filled with sediment derived from debris flows since then, primarily along its eastern margin. Sparks Lake has an average depth of 1 foot and a maximum depth of 7 feet (Wikipedia, 2015).

2.2 Geologic Mapping

According to the Geologic map of the Bend 30- x 60-minute quadrangle (Sherrod, et al., 2004), the project site is mapped as Qal, or Alluvium (Holocene and Pleistocene). The alluvium is described as unconsolidated deposits of sand and gravel along streams and in valley bottoms. Other nearby deposits include Qbcy or Basalt of the Cayuse Crater to the northeast, Qd or Dacite to the northwest, Qgs or Till of

Suttle Lake advance (of Cabot Creek glaciation of Scott, 1977) to the north and west, and Qbec or Basalt of Egan cone to the south-southeast. The borings encountered unconsolidated deposits consistent with the alluvium described in the map.

2.3 Geologic Hazards

According to the Oregon HazVu website (DOGAMI, 2015), the project site is mapped with the hazards summarized in Table 2.3-1 below:

Table 2.3-1. Mapped Risks for Geologic Hazards

Hazard Mapped Risk

Active Faults None mapped within 6 miles

Earthquake Liquefaction (Soft Soil) Hazard Moderate

Expected Earthquake Shaking Very Strong

Cascadia Expected Earthquake Shaking Very Strong

Landslide Hazard None in site proximity

Volcano Hazard Moderate bordering on High Hazard Zone

According to the HazVu website, the most common volcano-related hazards are ash (tephra), lahars

(volcanic mud flows), lava and debris flows, avalanches, and pyroclastic flows. The data depict areas where volcanic hazards may occur during or after volcanic activity. Volcanoes can produce volcanic ash, mudflows, debris flows, avalanches of hot volcanic material, lava flows, and landslides, for which the size and recurrence interval is beyond the scope of this report. The recommendations provided in this report assume that the risk of volcano hazards are simply acknowledged and cannot feasibly be mitigated. Very

GR18-15 Page 10 strong ground shaking from earthquakes and liquefaction hazards will be discussed in more detail in the

Seismicity section of this report.

2.4 Climate Data

The project is located central Oregon with light to moderate rainfall year-round and moderate to heavy snowfall typically occurring from October through May. Table 2.4-1and Table 2.4-2 summarize average temperatures, precipitation, and snow depth measurements from two of the nearest weather stations at

Sunriver, Oregon, located approximately 19 miles east-southeast of the site and Wikiup Dam, Oregon located approximately 24 miles south of the site (Western Region Climate Center, 2015).

Table 2.4-1. Period of Record Monthly Climate Summary for Sunriver, OR (358246)

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual

Average Max.

Temperature (°F)

38.6 42.0 48.2 55.0 63.1 71.7 83.7 82.4 75.5 61.1 45.6 37.0 58.7

Average Min.

Temperature (°F)

19.8 20.4 24.0 25.7 32.6 37.6 41.4 39.7 32.5 26.7 24.1 19.0 28.6

Average Total

Precip.(in.)

2.66 1.60 1.43 1.05 1.43 0.98 0.49 0.61 0.39 1.41 2.26 3.32 17.64

Average Total

SnowFall (in.)

16.0 8.7 4.8 2.6 0.3 0.0 0.0 0.0 0.0 0.8 8.4 18.3 60.0

Average Snow

Depth (in.)

8 9 3 0 0 0 0 0 0 0 1 5 2

Notes:

Period of Record: 04/01/1998 to 01/20/2015.

Percent of possible observations for period of record: Max. Temp.: 96.7% Min. Temp.: 96.6% Precipitation: 96.2%

Snowfall: 96.4% Snow Depth: 92.7%.

Table 2.4-2. Period of Record Monthly Climate Summary for Wikiup Dam, OR (359316)

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Annual

Average Max.

Temperature (F)

37.7 41.8 46.2 53.6 62.3 70.0 80.6 79.8 73.1 60.8 45.6 38.3 57.5

Average Min.

Temperature (F)

16.9 20.0 23.3 27.7 33.8 39.7 43.7 41.9 35.2 29.2 24.7 19.2 29.6

Average Total

Precipitation

(in.)

3.33 2.21 1.79 1.08 1.22 1.09 0.59 0.70 0.65 1.52 2.98 3.53 20.70

Average Total

SnowFall (in.)

21.3 13.5 10.2 2.9 0.3 0.0 0.0 0.0 0.0 1.2 9.5 19.5 78.5

Average Snow

Depth (in.)

10 9 5 0 0 0 0 0 0 0 1 5 2

Notes:

Period of Record: 05/01/1941 to 01/20/2015.

Percent of possible observations for period of record: Max. Temp.: 98.7% Min. Temp.: 98.7% Precipitation: 99.3%

Snowfall: 99.1% Snow Depth: 94.5%.

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3 Subsurface Information

The conclusions and recommendations of this report are based on the subsurface conditions described in this section. If conditions are encountered during construction that differs from that described below, the

WFLHD Geotechnical Section should be contacted immediately to review the conditions and confirm or modify the recommendations.

3.1 Subsurface Investigation

The exploration program at the site consisted of two subsurface borings completed on September 22-23, 2014. One boring was completed at each abutment as shown on Figure A-1, Boring Locations Map in

Appendix B. The borings were drilled from the existing roadway and were advanced to a depth of 100 feet below ground surface. The boring logs are included in Appendix C and laboratory test results are included in Appendix D.

3.2 Subsurface Profile

The subsurface materials were similar at each boring and consisted predominantly of silty sand with varying amounts of gravel and occasional layers of gravel and silt. These deposits are interpreted to be primarily alluvial in origin with possibly some lacustrine deposits. Corrected standard penetration test

(SPT) values, also known as (N1)60 values, ranged from 3 to greater than 100 blows per foot (bpf) indicating the soils range from very loose to very dense. The average (N1)60 value was 32 bpf and 23 bpf for the East and West abutments respectively. In both borings, a dense to very dense layer, with corrected blow counts ranging from 45 to 100, occurs between about 60 and 80 feet below ground surface.

3.3 Groundwater Observations

Groundwater was encountered in both borings during drilling between approximately 4 and 5 feet below ground surface, which is close to the elevation of the water level in the adjacent Fall Creek. The groundwater table is expected to be influenced by and fluctuate with the adjacent stream surface elevation, particularly during spring thaw and following periods of heavy precipitation.

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4 Seismicity

4.1 Site Seismicity

The procedures outlined in Section 3.10 of the 7 th Edition (2014) of the AASHTO LRFD Bridge Design

Specifications (BDS) were followed to characterize the seismic hazards. These procedures use a design earthquake with a 7 percent probability of exceedance in 75 years, which equates to a return period of approximately 1,000 years.

Information from the USGS Earthquake Hazards Program website was used to locate nearby faults.

According to USGS information, the closest mapped Quaternary age fault is the La Pine graben faults approximately 8 miles south-southwest of the project site. However, the age category of this fault is in the less than 750,000 years category, and the fault line is inferred. The closest fault considered to be “active”, which is typically considered to have evidence of movement within the last 10,000 years, is the Metolius fault zone, Northwest Rift zone section approximately 14 miles east-northeast of the project. Since no active faults are located within 6 miles of the bridge, additional studies do not need to be performed to quantify near fault effects on ground motions per AASHTO.

Typically, the AASHTO general procedures in section 3.10.2.1 are used for determining the site class from shear wave velocity, standard penetration resistance, or undrained shear strength data in the upper

100 feet of the soil profile. Due to the potential liquefaction hazard and deep soil profile, a site-specific site response analysis was performed to more accurately determine the seismic response spectra for use in structural and geotechnical design. The Seismic Site Response Analysis report was prepared by Shannon and Wilson and is included in Appendix F of this report. We recommend using the response spectra from this report for seismic structural design.

Seismic site classes range from A to F and are arranged in order of decreasing density of subsurface materials and increasing susceptibility to structural damage as a result of an earthquake. The average standard penetration resistance in the upper 100 feet of the borings indicate the Fall Creek Bridge site classifies as Site Class D.

4.2 Liquefaction

Soil liquefaction is a phenomenon in which a cohesionless soil deposits below the groundwater table loses a substantial amount of strength due to pore pressure generation resulting from earthquake strong ground shaking (Kavazanjian, 2011). A liquefaction analysis was performed using the guidelines provided in the

AASHTO LRFD Bridge Design Specifications (BDS) and the 2013 Washington State Department of

Transportation (WSDOT) Geotechnical Design Manual (GDM). Notably, the procedures discussed in

Appendix 6-A.2 of the WSDOT GDM were used to perform the liquefaction using the WSDOT software

WSLiq developed by Professor Steve Kramer of the University of Washington. This software performs the recommended deaggregation analyses, considers multiple earthquake sources, and incorporates several different methods of analyses using the WSDOT recommended weighting. The results of the liquefaction analyses are summarized in Table 4.2-1 below. Detailed WSLiq results are included in

Appendix E of this report.

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Table 4.2-1. Liquefaction Analyses Results

Boring No. Depths of Layers Predicted to Liquefy (ft)

Estimated Seismic

Settlement (ft)

Estimated Lateral

Spreading (ft)

FCB14-01 9-11.5, 35-40

0.3 0.4

FCB14-02 10-15, 17.5-25, 50-60 0.8 0.7

Note: 1 Maximum considered liquefaction depth was limited to 75 feet per AASHTO BDS.

The results of the analysis indicate relatively low estimated settlements and lateral spreading displacements. Based on discussions with the Forest Service, we understand that satisfying the no-collapse criteria only will be sufficient design standards for this bridge. We understand that the single-span bridge will be designed with integrated abutments that should be capable of tolerating ground deformations of these magnitudes without collapse. Therefore, no mitigation measures, such as ground improvement, are recommended.

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5 Foundation Recommendations

5.1 Bridge Foundations Considerations

Both shallow and deep foundation concepts were considered for support of the superstructure at this location. Site conditions, subsurface conditions, scour, design loading, constructability, and cost were the major factors considered when evaluating foundation alternatives.

Shallow foundations, including a Geosynthetic Reinforced Soil - Integrated Bridge System (GRS-IBS) were considered. A shallow foundation such as a spread footing or GRS abutment wall would need to bear below the estimated scour elevation of 5419 feet, as discussed in section 5.2. This is approximately

15 feet below the current roadway grade and approximately 10 feet below the groundwater table. The temporary excavation would be difficult and would require the need for significant dewatering. The excavation would also likely encounter flowing and/or heaving sands and would almost certainly require shoring. Based on these considerations, a shallow foundation is not recommended.

Both driven piles and drilled shafts are feasible deep foundation alternatives for support of the proposed superstructure. However, based on the load support requirements for the proposed structure and relatively high costs for drilled shaft construction, drilled shafts are not recommended. Driven piling is therefore the preferred option for support of the proposed superstructure. It will be more cost effective and can typically be installed more quickly as compared to drilled shafts.

While driven piling is the recommended foundation type, there are some risks that should be considered in the design. Due to the scour elevation and the nature of subsurface materials, the piling will need to be driven relatively deep to achieve the required capacity as discussed in the following sections. Also, the type and densities of subsurface materials could result in piles “running” without achieving the required capacity. Furthermore, there is also risk of encountering manmade and natural obstructions in the ground that may require pre-drilling or relocation of the affected piles.

5.2 Scour

Scour elevations were provided by Mr. Jim Neighorn of the WFLHD Hydraulics Group. The 100-year scour elevation was provided as 5420.7 feet and the 500-year scour elevation was provided as 5419.2 feet.

The scour elevations provided are total scour including both local and contraction scour. As the two scour elevations are close, a scour elevation of 5419 was used for the foundation analysis as presented in this report.

5.3 Bridge Layout

At each abutment the superstructure will be supported on five 18-inch diameter steel piles connected with reinforced concrete pile caps.

The new bridge structure will have the following characteristics:

One span of approximately 65 feet

Total width of 36.5 feet

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Raised height of approximately 3 feet above the existing bridge

Zero offset from the existing bridge centerline

5.4 Design Loads

The final design loads were provided by the WFLHD Structures group as shown in Table 5.4-1.

Table 5.4-1. Structural Design Loads

Service I Limit State Strength I Limit State

Load Type

Unfactored

Load

(kips)

Factor

Factored

Load (kips)

Factor

Factored

Load

(kips)

Dead load of superstructure and substructure (DC)

528 1.0 528 1.25 660

Dead load of future wearing surface (DW)

29 1.0 29 1.50 44

Vehicular live load (LL) 144 1.0 144 1.75 252

Total 701 - 701 - 956

Total factored axial load per abutment, for the Strength I Limit State, is 956 kips. The recommendation is for 5 piles at each abutment, resulting in a Strength I factored load per pile (Qp) of 191.2 kips. The 5 recommended piles at each abutment do not include any additional piles needed to support wing walls, if necessary.

Downdrag may occur due to seismic settlement from liquefaction. Downdrag loads develop when soil settles and pulls down on a pile that is restrained from movement at the tip, which may occur at this site since the pile tips should be bearing in a layer of dense to very dense gravel. Downdrag effects are estimated to add up to approximately 30 kips to each pile. The structural engineer should check the piles for buckling failure from these additional loads under the Extreme Limit State.

If the magnitude of the ground surface liquefaction settlement is tolerable from a ductile connection standpoint at the pile cap, then the liquefaction downdrag, if any, can be ignored and the shaft can be allowed to settle. It is our understanding that the bridge structure can tolerate the expected liquefaction settlements discussed previously in this report.

5.5 Driven Piling Recommendations

5.5.1 Pile Type

Both 16-inch diameter and 18-inch diameter steel pipe piles were considered. The recommended pile type for both abutments is a closed-end 18-inch diameter pipe pile with 0.5 inch wall thickness. A 60 degree inside flange conical driving point is recommended for pile end closure. Since much of the pile capacity will be from skin resistance, the driving point should not project beyond the perimeter of the pile.

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5.5.2 Pile Group Configuration

It is our understanding that the existing abutments are supported on six timber piles each with butt diameters of approximately 12 inches. The preliminary recommendations memo, GM 24-14, recommended six 16-inch diameter piles; however, the location of a 6-pile group resulted in the proposed piles approximately 3 inches away from the same location as the existing timber piles on the west abutment, and an approximately 3 foot 7 inch offset on the east abutment. The original intent was to remove the existing timber piles and drive the new piles in those locations. However, the resulting void from removing the old piling would likely create a preferential path and result in new piles wandering significantly off the design locations. Also, it is our experience that removal of old timber piles often results in a broken portion of the pile remaining at depth, which would result in an obstruction for the new piles that would be difficult or impossible to remove.

Based on the above discussion, we recommend leaving the existing piles in place and installing the new piles in between the existing piles. Shifting the bridge slightly to the west is also recommended to maximize the distance between the old piles and the new piles to reduce the potential for obstruction and/or hard driving conditions from displacement-densified soils surrounding the timber piles. The resulting recommended pile group configuration is five 18-inch diameter piles spaced approximately 6.9 feet apart, pending field verification of the existing pile locations.

We recommend that the existing timber piles be cut-off at an elevation no higher than the bottom of the proposed pile cap, which we understand to be at an elevation of approximately 5427 feet.

5.5.3 Axial Capacities

Driven piling was analyzed for axial capacity by the static methods recommended in the AASHTO LRFD

Specification (2014) and by using the Driven computer program (Version 1.2). A graph showing both the nominal (unfactored) and factored axial geotechnical resistance versus depth for both 16-inch and 18-inch diameter close-end pipe piles is included in Appendix E. The graph shows the capacity for a single pile.

For pile groups in cohesionless soils, the pile group resistance is the sum of the resistance of all the piles in the group as long as the pile center-to-center spacing is at least 2.5 pile diameters. The axial capacity charts are intended to be used to estimate pile capacity and determine pile lengths for contract documents.

Based on foundation loads and a total of 5 piles per abutment, the piles are expected to achieve the required capacity at a depth of approximately 65 to 75 feet below ground surface, which equates to an elevation of approximately 5362 to 5372 feet. Care should be taken to avoid over-driving the piles through the dense gravel bearing layer. If the piles are driven through this bearing layer, the tip resistance could be reduced, which may result in longer piles or splicing of piles to achieve the required axial capacities.

To achieve the minimum Strength 1 factored axial geotechnical capacity of 192 kips per pile, the piles should be driven to a nominal (ultimate) capacity of 455 kips per pile. The ultimate capacity during pile driving takes into account a 0.65 geotechnical resistance factor in accordance with AASHTO when dynamic pile tests with signal matching are used to determine pile capacity, and resistance during driving within the zone of potential scour.

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Summary of pile recommendations:

• Pile type: closed-end 18-inch diameter with 0.5 inch wall thickness

• End closure: 60° conical driving point (inside flange)

• Number of piles: 5 minimum per abutment

• Pile center-to-center spacing: approximately 6.9± feet for piles placed in between the existing timber piles to remain, pending confirmation of existing timber pile spacing (minimum of 2.5 times the pile diameter)

• Drive piles to an ultimate capacity of 455 kips per pile

• Estimated pile tip elevation: between 5362 and 5372 feet

• Minimum pile tip depth below bottom of pile cap: 45 feet

• 1 dynamic load test with signal matching at each abutment

5.5.4 Pile Setup

Driving the pile will increase pore water pressure around the pile resulting in a reduction in the effective stress and the shear strength. This will reduce the nominal resistance of the pile during driving. As the excess pore pressures dissipate the nominal resistance with increase or “set-up”. AASHTO (2014) recommends allowing 2 days for silty sands for pile set-up. If the required nominal capacity for the piles is not attained by an elevation of 5362, the piles should be allowed to set-up for a period of 48 hours before performing a restrike.

5.5.5 Dynamic Pile Load Tests

Dynamic pile load tests and signal matching are recommended to verify the pile capacity during construction. One test pile is recommended at each abutment. The dynamic testing should be performed on the first pile driven at each abutment in order to establish the driving criteria for that abutment. The test should be performed during the initial pile driving and on a restrike test on the same pile. For a pile reaching the ultimate capacity during initial driving, the restrike should occur a minimum of 24 hours following initial driving. For a pile not reaching ultimate capacity by an elevation of 5362, the restrike should occur a minimum of 48 hours following the initial driving. No other piling should be driven in the same abutment during the set-up time period.

5.5.6 Settlement

The settlement at the bottom of the pile cap elevation due to service limit state load is anticipated to be less than ½ inch.

5.5.7 Lateral Analysis

Table 5.5-1 provides the soil parameters that are recommended to analyze lateral foundation loads. These values do not include reduction factors or load factors. A strength limit state resistance factor of 1.0 is specified in AASHTO (2014) for lateral geotechnical resistance of a single pipe or pile group. Factored strength limit state lateral loads should be used in the analysis.

The values in the table are for single piles and do not account for the reduced lateral resistance of piles in a group. P-multipliers are a function of center-to-center pile spacing and the number of rows of piles. P-multipliers are specified in Table 10.7.2.4-1 in AASHTO (2014).

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Table 5.5-1. Recommended Soil parameters for Lateral Analysis

Elevation

(feet)

Material

Description γ

(pcf) γ'

(pcf) φ'

(deg) p-y modulus, k

(lb/in

Above 5430 Silty Sand 110 110 30 25

5404 - 5430 Silty Sand 110 47.6 30 20

5399 - 5404 Sandy Silt 100 37.6 24 60

5371 - 5399 Silty Sand 110 47.6 32 60

5354 - 5371 Silty Sand and Gravel 120 57.6 36 125

Below 5354 Silty Sand with Gravel 115 52.6 34 125

NOTES:

1. Estimated groundwater elevation is 5430 feet.

2. γ = moist unit weight.

3. γ' = effective unit weight.

4. φ' = effective internal angle of friction.

5. k = reaction modulus (p-y modulus).

5.6 Wing Walls

Structural Backfill (FP-14 Subsection 704.04) should be used as backfill behind abutment walls and wing walls. Geocomposite sheet drains connected to drain pipe and weep holes should be installed behind walls to ensure adequate drainage. The soil parameters listed in Table 5.6-1 may be used to determine the lateral earth pressures exerted on the abutment walls and wing walls. These parameters assume a vertical wall with level ground at the top of the wall.

Table 5.6-1. 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. Geocomposite drains with connector grates, drain pipe, and weep holes are required.

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6 Earthwork Recommendations

Construction of the proposed project will require increasing the height of the existing embankment at the approaches by approximately 3 feet. Embankment widening, as well as new cut-slopes, are also proposed as shown on the project plans.

6.1 Cut and Fill Slopes

Proposed fill slopes should be constructed at a slope angle of 1V:2H or flatter. In space limited areas, fill slopes may be constructed up to a slope angle of 1V:1.5H for slopes less than 10 feet in vertical height.

Slopes steeper than 1V:2H will likely result in more rilling and erosion, slower revegetation, and possible sloughing. Slope rounding at the toe of fill slopes following standard WFL details should be constructed in all locations. In proposed embankment widening areas, newly constructed embankments should be benched into the sides of the existing embankments following the standard specifications.

Proposed cut slopes in soil material should be constructed at a slope angle of 1V:1:75H or flatter. Soil cut slopes of 1V:1.5H are acceptable if needed, but will result in varying levels of raveling, possible sloughing, and slower revegetation. Slope rounding following the WFLHD standard detail should be completed at the crest of all soil cut slopes.

Temporary excavation slopes should be excavated no steeper than 1:1 unless shoring is provided.

Temporary excavation slopes may need to be cut flatter than a 1:1 as determined by the construction contractor for worker safety and/or to meet federal regulations.

6.2 Subexcavation

Soft, wet, organic rich materials are present outside the limits of the existing embankment for much of the proposed project. For new embankment sections widened into these areas, in-situ materials outside of the existing roadway embankment, and in the foundation area for the proposed embankment, should be subexcavated to a minimum depth of 2.5 feet below existing ground or to firm, stable materials.

Groundwater will be encountered in many of the subexcavation areas. Crushed aggregate backfill is recommended to help facilitate placement and compaction. The crushed aggregate may be placed in loose lift thickness up to 30 inches. A Class 2, Type C geotextile is recommended at the base of the subexcavation. All subexcavated material should be considered unsuitable for re-use and wasted in accordance to project requirements.

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Toe-of-fill subexcavation is recommended for any newly constructed embankment slopes within the following station limits:

STA 799+50 – 805+60 LT

STA 800+00 – 800+70 RT

STA 802+20 – 804+80 RT

At a minimum, the width of the subexcavation should extend from the existing embankment toe to the proposed embankment toe, which will vary with the height of the proposed embankment.

6.3 On-Site Materials and Construction Considerations

On-site excavated material, excluding the material excavated from the subexcavation locations and the organic-rich material as discussed below, will likely consist of silty sand with varying amounts of gravel.

The silty sand material is expected to have a shrink of approximately 10% between in-situ volume and placed and compacted volume and a swell of approximately 5% between in-situ volume and loose condition such as in a haul vehicle or stockpile. Shrink and swell factors are rough estimates and commonly vary by +/- 5%.

The subsurface boring at the west abutment (FCB14-02) indicates organic rich sand and silt between about 2.5 and 6 feet below the existing ground surface. This material and any additional organic-rich material uncovered during the excavation should be removed and wasted appropriately.

Boulders were not reported on the boring logs from the drilling investigation. However, boulders are evident along the stream banks and within the stream channel. The common size of the boulders is 12 to

36 inches with a few up to approximately 4 feet in diameter. Boulders within the project area include both placed riprap and naturally occurring, river deposited boulders. The construction contractor should be prepared to encounter and remove boulders during excavation for the project.

6.4 Dewatering

Groundwater is shallow throughout the majority of the project area. Groundwater is expected at an elevation of approximately 5429-5430 feet and will vary based on the time of year and recent precipitation events. Groundwater will likely be encountered in the excavation for the pile caps and wing walls, the subexcavations, and possibly during other construction work. The construction contractor should be prepared for dewatering where necessary. Temporary dewatering should be the responsibility of the contractor to design, permit, implement, and maintain. Care should be taken to prevent running sand conditions that may undermine the existing roadway or other structures and utilities, if any.

GR18-15 Page 21

7 Limitations

This report was prepared to provide subsurface investigation results and geotechnical recommendations for a new bridge across Fall Creek in Deschutes National Forest, Oregon. Professional judgment and recommendations are presented in this report. They are based partly on evaluation of the technical information gathered and partly on the 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 or beyond the borings. The observed water levels and/or conditions indicated on the boring logs are as recorded at the time of the exploration. The water levels and/or conditions may vary considerably, with time, according to the climate, rainfall, and other factors and are otherwise dependent on the duration of, methods used in, and interpretations made from the exploration program.

If, during construction, soil conditions are encountered that vary from those discussed in this report, or if design loads, project stationing, and/or configurations change, the WFLHD Geotechnical Team should be notified immediately in order to evaluate what effects, if any, the changes have on the recommendations contained in this report. The recommendations presented in this report are applicable only to this specific site. These data are not to be used for other purposes.

Questions regarding this report should be addressed to Eric Lim, WFLHD Geotechnical Engineer, at

(360) 619-7826, or eric.lim@dot.gov.

mailto:eric.lim@dot.gov

GR18-15 Page 23

8 References

AASHTO LRFD Bridge Design Specifications, Seventh Edition (2014) American Association of State

Highway and Transportation Officials, Washington, D.C.

DOGAMI - Oregon Department of Geology and Mineral Industries, Oregon HazVu: Statewide

Geohazards Viewer, http://www.oregongeology.org/hazvu/, accessed 11/25/2015.

O’Grady, Patrick, O’Neill, Brian, (2015), Fall Creek Bridge Replacement Project: Results of Test

Excavations in the Bridge Replacement and Seismic Modification Project Area (Project OR PFH

46[13]); Museum Report 2015-040, University of Oregon State Museum of Anthropology, report dated

Oct. 14, 2015.

Oregon Department of Transportation, ODOT Geotechnical Design Manual, Volume 1, Chapter 6, November 2014.

Sherrod, D.R., Taylor, E.M., Ferns, M.L., Scott, W.E., Conrey, R.M., and Smith, G.A. (2004), Geologic map of the Bend 30- x 60-minute quadrangle, central Oregon, U.S. Geological Survey I-2683, scale

1:100,000.

Washington State Department of Transportation, WSDOT Geotechnical Design Manual, May 2015.

Western Regional Climate Center (2015), Cooperative Climatological Data Summaries, Sunriver, Oregon (358246): http://www.wrcc.dri.edu/cgi-bin/cliMAIN.pl?or8246, accessed 11/25/2015.

Wikipedia (2015), Sparks Lake: https://en.wikipedia.org/wiki/Sparks_Lake, accessed on 11/25/2015.

http://www.oregongeology.org/hazvu/ http://www.wrcc.dri.edu/cgi-bin/cliMAIN.pl?or8246 https://en.wikipedia.org/wiki/Sparks_Lake

APPENDIX A

Site Photographs

Photo A-1. Fall Creek Bridge, looking generally west

Photo A-2. Fall Creek Bridge, looking generally east

Photo A-3. Fall Creek Bridge, looking generally south (downstream)

Photo A-4. Fall Creek Bridge, southwest abutment

Photo A-5. Typical wet, soft ground area at the toe of the existing embankment

Photo A-6. Drilling at the west abutment

APPENDIX B

Boring Locations Maps

DIAGRAM IS FOR GENERAL LOCATION ONLY, AND IS NOT

INTENDED FOR CONSTRUCTION PURPOSES

FCB14-02

BORING LOCATIONS MAP

FALL CREEK BRIDGE REPLACEMENT

CASCADES LAKES HIGHWAY (HWY 46)

DESCHUTES COUNTY, OREGON

A-1

OR PFH 46(13)

DEC 2015

N.T.S.

Project No.

Scale:

File Name:

Date:

Figure

BORING MAP

Western Federal Lands Highway Division

610 East Fifth Street Vancouver, WA 98661

FCB14-01

APPENDIX C

Unified Soil Classification System

Soil Descriptive Terminology

Boring Logs

APPENDIX D

Laboratory Test Reports

Soil Index Test Results

Consolidation Test Results

Direct Shear Test Results

APPENDIX E

Design Axial Geotechnical Resistance Charts

Liquefaction Analyses Results

Attachment 3 – Axial Geotechnical Pile Resistance Graphs eric.lim Rectangle

Liquefaction Hazard Evaluation Report by WSLiq Program beta (May, 2009)

Site Name: Fall Creek Bridge

Site Location (N,W) = 44.030 , 121.738

Job No: FCB14-01

Analyst: EJL

Date: 7/9/2015 8:38:33 AM

=== Soil Profile ===

Unit: ft

The number of soil layers: 20

GWT at top of layer: 2

GWT depth: 2.50

SPT Energy Ratio (%): 78.10

Amplification Factors: Fpga= 1.55

Elevation: 0.00

Ground Surface: Infinite Slope (%)= 5

Layer Descpt. Thickness Unit Weight Nm N160 Vs

(ft) (lb/ft3) ft/sec

1 SW-SM 2.5 115.00 6 13.3 598.9

2 SW-SM 2.5 120.00 13 28.8 749.5

3 SW-SM 2.5 125.00 20 44.3 849.2

4 SM 2.5 110.00 4 8.9 532.5

5 SM 2.5 115.00 9 19.4 673.7

6 SM 2.5 125.00 21 41.5 861.3

7 GP-GM 2.5 130.00 73 133.0 1236.2

8 SM 5 120.00 14 23.2 765.8

9 SM 5 120.00 19 28.5 836.7

10 SM 5 120.00 11 15.2 714.0

11 SM 5 120.00 11 14.1 714.0

12 SW-SM 5 125.00 41 49.4 1045.7

13 ML 5 120.00 12 13.6 732.3

14 SW 5 125.00 26 28.1 916.3

15 SW 5 120.00 17 17.5 810.1

16 SM 5 125.00 44 43.5 1067.4

17 GP 5 130.00 75 71.0 1245.9

18 SW-SM 5 130.00 48 43.6 1094.7

19 SP-SM 5 125.00 24 21.0 895.3

20 GW 5 125.00 26 22.1 916.3

Layer FC PI wc/LL D50 Ini. Eff. Ini. Total

(%) (mm) Stress (psf) Stress (psf)

1 15 Unsat Unsat 1.000 143.8 143.75

2 10 0 1 1.000 359.5 437.50

3 10 0 1 1.000 509.8 743.75

4 25 0 1 0.400 647.5 1037.50

5 30 0 1 0.400 772.8 1318.75

6 20 0 1 0.400 916.8 1618.75

7 10 0 1 2.000 1079.5 1937.50

8 15 0 1 0.080 1308.0 2400.00

9 35 0 1 0.080 1596.0 3000.00

10 47 0 1 0.080 1884.0 3600.00

11 10 0 1 0.080 2172.0 4200.00

12 10 0 1 1.000 2472.5 4812.50

13 55 0 1 0.060 2773.0 5425.00

14 23 0 1 0.300 3073.5 6037.50

15 15 0 1 0.300 3374.0 6650.00

16 20 0 1 0.300 3674.5 7262.50

17 5 0 1 8.000 4000.0 7900.00

18 10 0 1 0.800 4338.0 8550.00

19 10 0 1 0.500 4663.5 9187.50

20 5 0 1 6.000 4976.5 9812.50

Soil Profile Plots

=== Susceptibility Evaluation ===

Threshold: 0.5

Weighting factors: B-I= 1.00 B-S= 0.00

Layer PI wc/LL B-I B-S Suscep. Index Potential

1 20.00 0.50 0.00 0.00 0.00 NO

2 0.00 1.00 1.00 0.76 1.00 YES

3 0.00 1.00 1.00 0.76 1.00 YES

4 0.00 1.00 1.00 0.76 1.00 YES

5 0.00 1.00 1.00 0.76 1.00 YES

6 0.00 1.00 1.00 0.76 1.00 YES

7 0.00 1.00 1.00 0.76 1.00 YES

8 0.00 1.00 1.00 0.76 1.00 YES

9 0.00 1.00 1.00 0.76 1.00 YES

10 0.00 1.00 1.00 0.76 1.00 YES

11 0.00 1.00 1.00 0.76 1.00 YES

12 0.00 1.00 1.00 0.76 1.00 YES

13 0.00 1.00 1.00 0.76 1.00 YES

14 0.00 1.00 1.00 0.76 1.00 YES

15 0.00 1.00 1.00 0.76 1.00 YES

16 0.00 1.00 1.00 0.76 1.00 YES

17 0.00 1.00 1.00 0.76 1.00 YES

18 0.00 1.00 1.00 0.76 1.00 YES

19 0.00 1.00 1.00 0.76 1.00 YES

20 0.00 1.00 1.00 0.76 1.00 YES

=== Initiation ===

Initiation - Multiple Scenario

Retrun Period (yrs) = 975

Models Selected :

--WSDOT Recommended--

Use NCEER, Boulanger & Idriss, and

Cetin's model with weighting factors of 0.4, 0.4, and 0.2 respectively.

---WSDOT Recommended------------

--- PGA = 0.192 Mw = 7.28---------

Layer (N1)60 CSR CRR FS Nreq

2 28.77 0.151 1.543 10.25 12.0

3 44.26 0.179 2.798 15.60 14.8

4 8.85 0.196 0.152 0.78 15.9

5 19.39 0.207 0.319 1.54 16.7

6 41.53 0.212 2.795 13.16 17.4

7 133.04 0.214 3.000 14.02 17.8

8 23.18 0.216 0.337 1.56 17.8

9 28.48 0.216 1.657 7.66 17.5

10 15.18 0.214 0.241 1.13 17.2

11 14.13 0.210 0.161 0.77 17.7

12 49.37 0.203 2.838 13.96 17.2

13 13.65 0.196 0.206 1.05 15.8

14 28.08 0.189 1.661 8.77 15.9

15 17.52 0.183 0.203 1.11 15.5

16 43.46 0.178 2.733 15.39 14.9

17 71.01 0.172 3.000 17.40 14.9

18 43.64 0.168 2.675 15.91 14.4

19 21.04 0.164 0.216 1.31 14.1

20 22.07 0.162 0.214 1.32 13.9

Table of FS

# Depth WSDOT ft PL=0.60

2 -3.75 10.25

3 -6.25 15.60

4 -8.75 0.78

5 -11.25 1.54

6 -13.75 13.16

7 -16.25 14.02

8 -20.00 1.56

9 -25.00 7.66

10 -30.00 1.13

11 -35.00 0.77

12 -40.00 13.96

13 -45.00 1.05

14 -50.00 8.77

15 -55.00 1.11

16 -60.00 15.39

17 -65.00 17.40

18 -70.00 15.91

19 -75.00 1.31

20 -80.00 1.32

=== Effects ===

** Response Spectrum **

FSmin = 1

(curve data is saved as a file 'ReSpectrum.txt'.)

** Lateral Spreading **

>>>Multiple Scenario Results

Model Selected :

WSDOT Recommended (weighted average) using models of Baska & Kramer and Youd et al.

Baska & Kramer: 0.55 ft

Youd et al.: 0.21 ft

Idriss & Boulanger: 5.38 ft

Weighting factors: Baska and Kramer = 0.65

Youd et al. = 0.35

WSDOT Recommended: 0.43 ft

** Settlement **

>>>Multiple Scenario Results

Groud Surface Settlement MULTIPLE Scenario

Return Period (yrs) = 975

Model Selected :

WSDOT Recommended (weighted average) using all deterministic models.

Weighting factors = 0.25 for each model

WSDOT Recommended:

Total ground surface settlement = 0.29 ft

# Depth thickness ev Weight dh ft ft % ft

2 3.75 2.5 0.026 NaN 0.00

3 6.25 2.5 0.001 0.00 0.00

4 8.75 2.5 2.087 1.00 0.05

5 11.25 2.5 0.449 0.97 0.01

6 13.75 2.5 0.001 0.00 0.00

7 16.25 2.5 0.001 0.00 0.00

8 20.00 5.0 0.390 0.94 0.02

9 25.00 5.0 0.001 0.49 0.00

10 30.00 5.0 0.928 1.00 0.05

11 35.00 5.0 1.417 1.00 0.07

12 40.00 5.0 0.001 0.00 0.00

13 45.00 5.0 0.934 1.00 0.05

14 50.00 5.0 0.000 NaN 0.00

15 55.00 5.0 0.606 1.00 0.03

16 60.00 5.0 0.001 0.00 0.00

17 65.00 5.0 0.001 0.00 0.00

18 70.00 5.0 0.001 0.02 0.00

19 75.00 5.0 0.197 NaN 0.01

20 80.00 5.0 0.202 NaN 0.01

** Residual Strength **

====== Soil Layers Selected ==================

Select All Soil Layers (under GWT and susceptible).

====== Models Selected ========================

Use recommended models:

Kramer & Wang, Deterministic (KWD), w/ weighting factor = 0.5

Idriss & Boulanger (IDB), w/ weighting factor = 0.3

Olson & Stark (OLS), w/ weighting factor = 0.2

The residual strength is estimated as:

Residual Strength =

0.5*(Kramer & Wang) + 0.3*(Idriss & Boulanger) + 0.2*(Olson & Stark)

###### Unweighted Residual Strength ####################

Kramer & Wang Deterministic Model:

Layer 4: Sr = 127 psf = 6.1 kPa = 0.060 atm

Layer 5: Sr = 419 psf = 20.1 kPa = 0.198 atm

Layer 10: Sr = 429 psf = 20.6 kPa = 0.203 atm

Layer 11: Sr = 416 psf = 19.9 kPa = 0.196 atm

Layer 13: Sr = 452 psf = 21.6 kPa = 0.214 atm

Layer 15: Sr = 757 psf = 36.3 kPa = 0.358 atm

Idriss & Boulanger Model:

Layer 4: Sr = 70 psf = 3.4 kPa = 0.033 atm

Layer 5: Sr = 464 psf = 22.2 kPa = 0.219 atm

Layer 10: Sr = 1130 psf = 54.1 kPa = 0.534 atm

Layer 11: Sr = 486 psf = 23.3 kPa = 0.230 atm

Layer 13: Sr = 1364 psf = 65.3 kPa = 0.644 atm

Layer 15: Sr = 2024 psf = 96.9 kPa = 0.957 atm

Olson & Stark Model:

Layer 4: Sr = 62 psf = 3.0 kPa = 0.029 atm

Layer 5: Sr = 136 psf = 6.5 kPa = 0.064 atm

Layer 10: Sr = 271 psf = 13.0 kPa = 0.128 atm

Layer 11: Sr = 295 psf = 14.1 kPa = 0.140 atm

Layer 13: Sr = 367 psf = 17.6 kPa = 0.173 atm

Layer 15: Sr = 545 psf = 26.1 kPa = 0.257 atm

WSDOT Recommended Model:

Layer 4: Sr = 97 psf = 4.7 kPa = 0.046 atm

Layer 5: Sr = 376 psf = 18.0 kPa = 0.178 atm

Layer 10: Sr = 608 psf = 29.1 kPa = 0.287 atm

Layer 11: Sr = 413 psf = 19.8 kPa = 0.195 atm

Layer 13: Sr = 708 psf = 33.9 kPa = 0.335 atm

Layer 15: Sr = 1095 psf = 52.4 kPa = 0.517 atm

Liquefaction Hazard Evaluation Report by WSLiq Program beta (May, 2009)

Site Name: Fall Creek Bridge

Site Location (N,W) = 44.030 , 121.738

Job No: FCB14-02

Analyst: EJL

Date: 7/9/2015 8:25:23 AM

=== Soil Profile ===

Unit: ft

The number of soil layers: 18

GWT at top of layer: 2

GWT depth: 2.50

SPT Energy Ratio (%): 78.10

Amplification Factors: Fpga= 1.55

Elevation: 0.00

Ground Surface: Infinite Slope (%)= 5

Layer Descpt. Thickness Unit Weight Nm N160 Vs

(ft) (lb/ft3) ft/sec

1 SP-SM 2.5 115.00 5 11.1 568.1

2 OL,_SP-SM 2.5 115.00 6 13.3 598.9

3 GP-GM 2.5 120.00 11 24.3 714.0

4 SM 2.5 115.00 5 11.1 568.1

5 SM 2.5 110.00 2 4.4 435.5

6 SM 2.5 120.00 12 24.1 732.3

7 SM 2.5 115.00 5 9.4 568.1

8 SM 5 110.00 2 3.4 435.5

9 GM 5 120.00 12 18.7 732.3

10 ML 5 120.00 11 15.7 714.0

11 SM 5 20.00 14 19.8 765.8

12 ML-OL 5 120.00 13 18.2 749.5

13 GM 5 125.00 39 50.5 1030.7

14 SM 5 120.00 14 17.0 765.8

15 SW-SM 5 120.00 10 11.5 694.6

16 ML-OL 5 120.00 15 16.4 781.2

17 SM 5 130.00 74 76.8 1241.1

18 GM 10 130.00 50 48.4 1107.7

Layer FC PI wc/LL D50 Ini. Eff. Ini. Total

(%) (mm) Stress (psf) Stress (psf)

1 10 Unsat Unsat 0.250 143.8 143.75

2 15 0 1 0.250 353.3 431.25

3 10 0 1 8.000 491.0 725.00

4 15 0 1 1.000 628.8 1018.75

5 15 0 1 1.000 754.0 1300.00

6 15 0 1 1.000 885.5 1587.50

7 25 0 1 0.400 1023.3 1881.25

8 25 0 1 0.400 1208.0 2300.00

9 15 0 1 8.000 1471.0 2875.00

10 51 0 1 0.070 1759.0 3475.00

11 25 0 1 1.000 1797.0 3825.00

12 55 0 1 0.070 1835.0 4175.00

13 11 0 1 1.500 2135.5 4787.50

14 15 0 1 0.250 2436.0 5400.00

15 16 0 1 0.250 2724.0 6000.00

16 57 0 1 0.050 3012.0 6600.00

17 15 0 1 1.000 3325.0 7225.00

18 8 0 1 2.500 3832.0 8200.00

Soil Profile Plots

=== Susceptibility Evaluation ===

Threshold: 0.5

Weighting factors: B-I= 1.00 B-S= 0.00

Layer PI wc/LL B-I B-S Suscep. Index Potential

1 20.00 0.50 0.00 0.00 0.00 NO

2 0.00 1.00 1.00 0.76 1.00 YES

3 0.00 1.00 1.00 0.76 1.00 YES

4 0.00 1.00 1.00 0.76 1.00 YES

5 0.00 1.00 1.00 0.76 1.00 YES

6 0.00 1.00 1.00 0.76 1.00 YES

7 0.00 1.00 1.00 0.76 1.00 YES

8 0.00 1.00 1.00 0.76 1.00 YES

9 0.00 1.00 1.00 0.76 1.00 YES

10 0.00 1.00 1.00 0.76 1.00 YES

11 0.00 1.00 1.00 0.76 1.00 YES

12 0.00 1.00 1.00 0.76 1.00 YES

13 0.00 1.00 1.00 0.76 1.00 YES

14 0.00 1.00 1.00 0.76 1.00 YES

15 0.00 1.00 1.00 0.76 1.00 YES

16 0.00 1.00 1.00 0.76 1.00 YES

17 0.00 1.00 1.00 0.76 1.00 YES

18 0.00 1.00 1.00 0.76 1.00 YES

=== Initiation ===

Initiation - Multiple Scenario

Retrun Period (yrs) = 975

Models Selected :

--WSDOT Recommended--

Use NCEER, Boulanger & Idriss, and

Cetin's model with weighting factors of 0.4, 0.4, and 0.2 respectively.

---WSDOT Recommended------------

--- PGA = 0.192 Mw = 7.28---------

Layer (N1)60 CSR CRR FS Nreq

2 13.28 0.151 0.188 1.25 12.0

3 24.34 0.181 0.344 1.90 14.9

4 11.06 0.197 0.157 0.80 16.2

5 4.36 0.207 0.097 0.47 17.0

6 24.15 0.214 0.368 1.72 17.5

7 9.36 0.217 0.156 0.72 17.6

8 3.45 0.220 0.101 0.46 17.9

9 18.74 0.220 0.245 1.11 18.1

10 15.71 0.215 0.254 1.18 17.1

11 19.78 0.222 0.304 1.37 18.0

12 18.17 0.228 0.310 1.36 17.7

13 50.54 0.215 2.871 13.36 17.7

14 16.99 0.204 0.209 1.02 16.9

15 11.47 0.195 0.147 0.75 16.3

16 16.37 0.188 0.248 1.32 14.9

17 76.85 0.182 3.000 16.53 15.2

18 48.37 0.172 2.779 16.12 14.6

Table of FS

# Depth WSDOT ft PL=0.60

2 -3.75 1.25

3 -6.25 1.90

4 -8.75 0.80

5 -11.25 0.47

6 -13.75 1.72

7 -16.25 0.72

8 -20.00 0.46

9 -25.00 1.11

10 -30.00 1.18

11 -35.00 1.37

12 -40.00 1.36

13 -45.00 13.36

14 -50.00 1.02

15 -55.00 0.75

16 -60.00 1.32

17 -65.00 16.53

18 -72.50 16.12

=== Effects ===

** Response Spectrum **

FSmin = 1

(curve data is saved as a file 'ReSpectrum.txt'.)

** Lateral Spreading **

>>>Multiple Scenario Results

Model Selected :

WSDOT Recommended (weighted average) using models of Baska & Kramer and Youd et al.

Baska & Kramer: 0.98 ft

Youd et al.: 0.25 ft

Idriss & Boulanger: 20.75 ft

Weighting factors: Baska and Kramer = 0.65

Youd et al. = 0.35

WSDOT Recommended: 0.72 ft

** Settlement **

>>>Multiple Scenario Results

Groud Surface Settlement MULTIPLE Scenario

Return Period (yrs) = 975

Model Selected :

WSDOT Recommended (weighted average) using all deterministic models.

Weighting factors = 0.25 for each model

WSDOT Recommended:

Total ground surface settlement = 0.81 ft

# Depth thickness ev Weight dh ft ft % ft

2 3.75 2.5 1.190 0.98 0.03

3 6.25 2.5 0.203 0.97 0.00

4 8.75 2.5 1.785 1.00 0.04

5 11.25 2.5 4.809 1.00 0.12

6 13.75 2.5 0.337 0.90 0.01

7 16.25 2.5 2.092 1.00 0.05

8 20.00 5.0 5.367 1.00 0.27

9 25.00 5.0 0.907 0.99 0.04

10 30.00 5.0 0.905 0.99 0.04

11 35.00 5.0 0.536 0.98 0.03

12 40.00 5.0 0.542 0.97 0.03

13 45.00 5.0 0.001 0.00 0.00

14 50.00 5.0 0.927 0.99 0.05

15 55.00 5.0 1.522 1.00 0.08

16 60.00 5.0 0.395 0.99 0.02

17 65.00 5.0 0.001 0.00 0.00

18 72.50 10.0 0.001 0.00 0.00

** Residual Strength **

====== Soil Layers Selected ==================

Select All Soil Layers (under GWT and susceptible).

====== Models Selected ========================

Use recommended models:

Kramer & Wang, Deterministic (KWD), w/ weighting factor = 0.5

Idriss & Boulanger (IDB), w/ weighting factor = 0.3

Olson & Stark (OLS), w/ weighting factor = 0.2

The residual strength is estimated as:

Residual Strength =

0.5*(Kramer & Wang) + 0.3*(Idriss & Boulanger) + 0.2*(Olson & Stark)

###### Unweighted Residual Strength…