GR_7-17_Tom_Miner_Final_Foundation_Report.pdf

Tom Miner Creek Road Capital Improvements Project June 2017

Table of Contents 1-i

Geotechnical Report No. 7-17

Tom Miner Creek Road Capital Improvements Project

FINAL FOUNDATION REPORT

MT PARK 63(1)

Park County, Montana

June 2017

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Table of Contents i

TABLE OF CONTENTS

1 INTRODUCTION

1.1 Project Description

1.2 Purpose and Scope

2 GEOLOGY

2.1 Geologic Hazards

2.1.1 Site Seismicity

2.1.2 Liquefaction

3 SITE CONDITIONS

3.1 Average Temperatures and Precipitation

3.2 Scour

4 SUBSURFACE CONDITIONS

4.1 Tom Miner Creek Borings

4.2 Rock Creek Borings

4.3 Groundwater

5 FOUNDATION ANALYSIS AND RECOMMENDATIONS

5.1 Bridge Layout and Foundation Considerations

5.2 Design Loads and Bearing Resistance

5.3 Design Soil and Geotextile Parameters

5.4 GRS-IBS Layout

6 CONSTRUCTION CONSIDERATIONS

6.1 Excavation

6.2 Dewatering

6.3 GRS-IBS Construction

7 LIMITATIONS

8 REFERENCES

List of Figures ii

LIST OF FIGURES

Figure 1-1 Project Location Map

Figure 1-2 Vicinity Topographic Map

Figure 2-1 Excerpt from the Geologic Map of the Gardiner 30’x60’ Quadrangle

Figure 2-2 Quaternary Faults Map for the Site Vicinity

Figure 2-3 Five Percent Damped Design Response Spectrum

Figure 5-1 Typical GRS-IBS Cross-Section (Adams, et al. 2011)

LIST OF TABLES

Table 2-1 Summary of Seismic Parameters

Table 2-2 Liquefaction Analyses Results

Table 3-1 Climate Data Summary

Table 5-1 Final Bridge Design Loads

Table 5-2 Soil Parameters Used for GRS-IBS Design

APPENDICES

APPENDIX A

Site Photographs

APPENDIX B

Boring Location Plans

APPENDIX C

Field Classifications for Soil and Rock

Unified Soil Classification System

Boring Logs B16-01 to B16-04

APPENDIX D

Laboratory Test Reports

APPENDIX E

Liquefaction Analyses Results

Tom Miner Bridge GRS-IBS LRFD Calculations

Rock Creek Bridge GRS-IBS LRFD Calculations

Introduction 1

1 INTRODUCTION

This report provides the geotechnical investigation results, analysis, and final foundation recommendations for the Tom Miner Creek Road Capital Improvements Project. The project is located approximately 18 miles north of Gardiner, Montana off Highway 89, as shown in Figure

1-1, Project Location Map, and Figure 1-2, Vicinity Topographic Map. The road provides access to the Custer Gallatin National Forest and Montana Fish, Wildlife and Parks Gallatin and Dome

Mountain Wildlife Management Study areas.

1.1 PROJECT DESCRIPTION

The project involves replacement of two deficient bridges: Tom Miner Creek Bridge; and Rock

Creek Bridge. The existing Tom Miner Creek Bridge is approximately 19 feet long and 16 feet wide and is experiencing significant undermining of the abutments due to scour. Rock Creek

Bridge is approximately 17.5 feet long by 16 feet wide. This bridge has experienced failure of the southwest wingwall/abutment due to undermining, which has been temporarily repaired with steel cables anchored under the roadway. It also exhibits a large vertical crack in the northwest wingwall, erosion between the roadway and northeast abutment, and undermined abutments on the entire south side and northwest side. Photos of the bridges are included in Appendix A.

The proposed replacement bridges will consist of longer bridge spans with riprap lined channels. The new decks are currently planned to be approximately 52-foot long by 28-foot wide single-span precast concrete girder decks supported on Geosynthetic Reinforced Soil –

Integrated Bridge System (GRS-IBS) abutments. The roadways will remain gravel surfaced. We understand that some minor improvements and repairs are planned for nearby Carbella Bridge as part of the overall project, but do not require geotechnical input.

1.2 PURPOSE AND SCOPE

The purpose of this report is to provide geotechnical recommendations for bridge foundation design and construction considerations. The geotechnical scope of work included a visual reconnaissance along the proposed alignment, a subsurface exploration program consisting of four geotechnical test borings, laboratory soil index testing, preparation of interim memorandums, participation in bridge foundation selection meetings, and preparation of this report. The geotechnical borings and laboratory tests were completed by Western Federal

Lands Highway Division (WFLHD) and a drilling subcontractor under the direction of a WFLHD geotechnical engineer.

The following reports were previously prepared by WFLHD and are available by request:

Initial Geotechnical Findings Memorandum, GM 24-16, dated August 2016

Preliminary Foundation Recommendations Memorandum, GM 34-16, dated November

This report supersedes these previous reports for this project.

Figure 1-1 Project Location Map

Figure 1-2 Vicinity Topographic Map

Rock Creek

Bridge

Tom Miner

Creek Bridge

Geology 3

2 GEOLOGY

As shown in Figure 1-2, the bridge sites are located in a relatively broad valley at the base of mountainous terrain. Each bridge is near their respective creek’s confluence with the

Yellowstone River. The Geologic Map of the Gardiner 30’ x 60’ Quadrangle, South-Central

Montana (Berg and others, 1999) maps both bridge locations in an undivided Glacial deposit, Qg, as shown in an excerpt in Figure 2-1 below. This deposit is described as dominantly unsorted and unstratified sediment of Pleistocene glacial moraines and other associated glacial and glaciofluvial deposits. Qg also includes Holocene glacial deposits and rock glacier deposits, and may include subordinate alluvium, colluvium, talus, landslide deposits, and boulder fields.

Other nearby deposits include alluvium of modern channels and flood plains, Qal, which are mapped along the east side of Tom Miner Road and roughly follows the Yellowstone River.

Upland deposits include: glacial till, Qgt; landslide deposits, Qls; mylonite, p-Cmy; gneissic rocks, Agn; and, rhyolite or rhyolite sediment (Eocene), Tr. A dashed line runs north-northwest between the two bridge sites, which indicates an inferred fault line. However, as discussed later in this report, this fault does not show up on the Quaternary faults search. Therefore, the fault is likely considered inactive.

Figure 2-1 Excerpt from the Geologic Map of the Gardiner 30’x60’ Quadrangle

Rock Creek

Bridge

Tom Miner

Creek Bridge

4 Geology

2.1 GEOLOGIC HAZARDS

Geologic hazards can include active faults, liquefaction and related phenomenon, soft or subsiding ground, strong ground shaking, and landsliding, among other natural hazards. Our search did not discover a published geologic hazard map for the vicinity. Based on the geologic mapping and the subsurface conditions encountered in our borings (discussed later in this report), it is our opinion that the relevant geologic hazards in the site vicinity include: active faults, liquefaction/lateral spreading, and strong ground shaking. These hazards are discussed further in the Site Seismicity section below.

2.1.1 SITE SEISMICITY

Information from the USGS Quaternary fault and fold database for the United States website was used to locate nearby active faults. According to the website, the Emigrant fault, southern section, runs northeast to southwest near the site vicinity, as shown in Figure 2-2 below. The normal fault is described as 69.5 kilometers (42.3 miles) in length with 0 degrees strike and a northwest dip direction. The slip rate is reported to be in the 0.2-1 millimeters per year category, and the age is reported to be in the less than 15,000 years category. The dashed line of the mapping website indicates that the fault location is inferred and the southwestern mapped end stops on the east side of Highway 89. The map literature indicates that the sole source data for the fault is from detailed mapping and reconnaissance studies of scarp morphology. No detailed studies, such as trenching, have been conducted.

AASHTO LRFD Bridge Design Specifications (7th Edition, 2014, with 2015 and 2016 Interim

Revisions) use earthquake design ground motion with a 7 percent probability of exceedance in

75 years, approximately equivalent to a return period of 1,000 years. The seismic hazard at the site and the importance of the proposed bridges dictate the level of seismic analysis that is required for the design. The seismic hazard principles within the current AASHTO

Specifications are: 1) small to moderate earthquakes should be resisted without significant damage; 2) realistic seismic ground motion intensities and forces should be used in the design;

and 3) exposure to shaking from large earthquakes may cause damage to the bridge, but the probability of collapse will be low and the damage will be limited to areas of the structure that are accessible for inspection and repair.

The AASHTO LRFD Bridge Design Specifications state that a site-specific probabilistic analysis to develop design response spectra shall be used if the site is located within 6 miles of an active fault and studies shall be considered to quantify near-fault effects on ground motions to determine if these could significantly influence the bridge response. The Emigrant fault southern section appears to be within approximately ½ to 1 mile from the bridge sites.

USGS hazard mapping efforts are very comprehensive and include a series of regional workshops to gather input from local geologic experts and to improve seismic source models.

This level of effort cannot be easily duplicated and thus site-specific seismic hazard analyses are generally not justified outside of major projects on life-line routes.

Geology 5

Figure 2-2 Quaternary Faults Map for the Site Vicinity

The results of a seismic deaggregation found that the Emigrant fault already contributes significantly to the seismic hazard determined using the USGS hazard maps. Therefore, the higher ground motion due to the proximity of the active fault has already been accounted for in the national ground motion maps. Furthermore, AASHTO states that directivity effects are normally evaluated only for essential or critical bridges having natural periods of vibration longer than 0.5 second. Therefore, we feel use of the general procedure using the national ground motion maps is appropriate for this project.

Project Area

Emigrant fault, southern section

6 Geology

The procedures outlined in Section 3.10 of the AASHTO LRFD manual were followed to characterize the seismic hazard. These procedures use a design earthquake with a 7 percent probability of exceedance (PE) in 75 years, which equates to a return period of approximately

1,000 years. Based on the AASHTO procedures, and the standard penetration resistance in the top 100 feet of the soil profile at the project site, the AASHTO seismic Site Class for both bridge sites is Site Class D.

The U.S. Seismic Design Maps were used to determine the peak ground acceleration and spectral accelerations at the project site based on Site Class B rock. The spectral accelerations were then scaled to Site Class D using the site factors recommended by AASHTO to represent the seismic accelerations based on actual ground conditions. The results of this analysis presented in Table 1 may be used for both the Tom Miner Creek Bridge and Rock Creek Bridge sites. It should be noted that the U.S. Seismic Design Maps website uses the 2002 USGS dataset for the AASHTO 2009 Guide Specifications for LRFD Seismic Bridge Design selection, which is still the dataset referenced by the 2016 AASHTO LRFD BDS.

Table 2-1 Summary of Seismic Parameters

Site Latitude 45.19938°

Site Longitude -110.90837°

Site Class at Project Site

(by Soil Type and Penetration Resistance in Top 100 feet of Soil

Profile)

D

Horizontal Peak Ground Acceleration on Site Class B Rock (PGA) 0.290

Horizontal Response Spectral Acceleration at a

Period of 0.2 sec on Site Class B Rock (Ss) 0.697

Horizontal Response Spectral Acceleration at a

Period of 1.0 sec on Site Class B Rock (S1) 0.210

Mapped Peak Ground Acceleration Coefficient, FPGA 1.220

Mapped Short-Period Spectral Acceleration Coefficient, Fa 1.242

Mapped 1-sec Period Spectral Acceleration Coefficient, Fv 1.979

Scaled Peak Ground Acceleration for Project Site, Site Class D

(As) 0.354

Scaled Horizontal Response Spectral Acceleration at a

Period of 0.2 sec for Project Site, Site Class D (SDS) 0.866

Scaled Horizontal Response Spectral Acceleration at a

Period of 1.0 sec for Project Site, Site Class D (SD1) 0.416

AASHTO Seismic Zone 3

The values in Table 2-1 were used to develop the 5-percent-damped-design response spectrum shown in Figure 2-3 below for the project site.

Geology 7

Figure 2-3 Five Percent Damped Design Response Spectrum

2.1.2 LIQUEFACTION

Soil liquefaction is a phenomenon in which cohesionless soil deposits below the groundwater table lose 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 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. A summary of the liquefaction analyses for the two bridge sites are summarized in Table 2-2 below. Detailed analysis results are included in Appendix E.

Table 2-2 Liquefaction Analyses Results

Bridge / Exploration

No.

Depths of Layers

Predicted to Liquefy (ft)

Estimated Seismic

Settlement (ft)

Estimated Lateral

Spreading (ft)

Tom Miner/BH16-01 25 – 40+ 0.5+ 2.10+

Rock Creek/BH16-04 None 0.01 0.87

8 Geology

The results of the liquefaction analyses indicate that liquefaction is a low risk at Rock Creek

Bridge. The results for Tom Miner Bridge indicate a moderate risk of liquefaction, relatively low estimated settlements and low-moderate lateral spreading displacements, in our opinion. Due to the low volume of the bridges, we anticipate that satisfying the no-collapse criteria only will be sufficient design standards for these bridges. It would likely be more cost effective to repair damage or displacements to the bridges rather than attempt to design them to resist displacements from earthquake forces. Since Tom Miner is a single-span bridge, the bridge deck should help restrain displacements from lateral spreading and prevent collapse of the bridge. Furthermore, GRS-IBS abutments (as proposed and discussed below) are flexible structures that should be capable of tolerating ground deformations of these magnitudes without collapse. Therefore, no mitigation measures, such as ground improvement, are considered feasible for the small size of the project. If this assertion is not shared by the owner, we should be contacted to provide additional recommendations for mitigation or further analysis.

Site Conditions 9

3 SITE CONDITIONS

The Tom Miner Creek Bridge site is located in a relatively flat area adjacent to irrigated agricultural and residential properties. The channel gradients were reported to be approximately 1 to 2.5 percent upstream to 1 to 3 percent downstream of the bridge. (Neighorn, 2016) The existing cast-in-place concrete abutments and wingwalls are being undermined by stream scour, especially the north abutment. The soils exposed under the abutment footings appear to be large gravel, although numerous boulders are visible in the stream channel and along the banks. The stream banks soils appear to consist largely of silty sand with gravel and are well vegetated. Some boulders placed downstream of the bridge at a turn in the stream appear to have been placed as revetment.

Rock Creek Bridge is located in steeper terrain than Tom Miner Creek Bridge. The channel gradients were reported to be approximately 3 to 4 percent upstream to 6 to 9.5 percent downstream of the bridge. (Neighorn, 2016) The bottom of the abutment footings at Rock Creek

Bridge were not visible due to the water levels at the time of our site visits. However, we understand that the entire south abutment and the northwest portion of the abutment/wingwall were undermined by scour, which apparently caused the structural damage to the abutments and wingwalls. It appears that repairs to the bridge include ground anchors with cable wraps around the failed abutment and southwest wingwall. We also understand that the large boulders in the stream channel were placed as revetment along the banks near the bridge, as well as to create downstream rock weirs to pool water and reduce velocity through this reach. The stream banks were well vegetated obscuring view of the surface soils. Cobbles, gravels, and boulders were visible in bare areas between the vegetation.

Photos of the bridges and streams are included in Appendix A.

3.1 AVERAGE TEMPERATURES AND PRECIPITATION

Table 3-2 shows the average maximum and minimum temperatures, average monthly precipitation, and average monthly snowfall data for the period from 1956 to 2016 for the

Gardiner, Montana (243378) weather station (Western Region Climate Center, 2017).

10 Site Conditions

Table 3-1 Climate Data Summary

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

Avg. Max.

Temp. (F)

33.1 38.2 46.6 56.1 66.4 76.3 86.2 84.6 74.3 60.6 42.8 33.8 58.2

Avg. Min.

Temp. (F)

14.2 17.3 23.6 30.5 38.3 45.6 51.9 50.5 42.1 33.4 23.1 16.0 32.2

Avg. Total

Precip. (in.)

0.43 0.34 0.54 0.68 1.56 1.48 1.05 0.91 0.85 0.80 0.64 0.46 9.73

Avg. Total

Snowfall

(in.)

5.5 3.0 3.5 2.8 0.5 0.0 0.0 0.0 0.1 0.4 4.1 5.5 25.5

Avg. Snow

Depth (in.)

2 1 0 0 0 0 0 0 0 0 0 1 0

Note:

1) Period of Record : 04/12/1956 to 06/07/2016.

2) Percent of possible observations for period of record: Max. Temp.: 89.9% Min. Temp.: 89.9%

Precipitation: 88.2% Snowfall: 74.3% Snow Depth: 72.9%.

3.2 SCOUR

The streams were evaluated by WFLHD hydraulics engineers. Scour elevations were provided by Jim Neighorn of the WFLHD Hydraulics Group in a Hydraulics TS&L Report dated, December 29, 2016 (Neighorn, 2016). The combined long term degradation and abutment scour elevations were estimated to be 5034.0 feet for Tom Miner Creek Bridge and 4984.1 feet for Rock Creek Bridge for the 500-year scour check flood event. No contraction scour is predicted since the new bridges will be widened to span the full channel width.

The hydraulics report stated that excavation below the stream levels to set the foundations to these scour depths would be difficult for abutment construction due to dewatering issues in highly permeable coarse materials. Therefore, scour countermeasures consisting of Class 4 riprap 3.5 feet thick were recommended for each abutment. By installing the scour countermeasures, the bottom of the GRS-IBS abutments can be constructed to the long-term degradation elevations of 5039.3 feet for Tom Miner Bridge and 4990.3 feet for Rock Creek

Bridge without regard to abutment scour. Please refer to the hydraulics report for more information.

Subsurface Conditions 11

4 SUBSURFACE CONDITIONS

Four subsurface borings were completed at the site on June 22 through 24, 2016 consisting of one boring at each abutment of the two bridges to be replaced. The borings were drilled on the side of the existing roadway and were advanced to depths of 8.5 to 100.5 feet below ground surface. The boring location maps are included in Appendix B, the boring logs in Appendix C, and the laboratory test results in Appendix D.

4.1 TOM MINER CREEK BORINGS

Boring BH16-01 was advanced on the south side of Tom Miner Creek and encountered dense poorly-graded gravel and cobbles with silt and sand in the upper approximate 6 feet. We interpreted this material to be embankment fill material. From 6 to 8 feet below the ground surface, the borings encountered very dense silty gravel with sand material, which is most likely alluvium. At 8 feet, the borings encountered auger refusal, at which point the driller switched to a casing advancer to attempt to drill through the obstruction. The casing advancer was able to penetrate through a likely boulder at approximately 10.3 feet, where the driller discovered that the casing advancer bit was destroyed, likely by a lack of drilling fluid circulation due to large voids in the materials (see Photo A-15 in Appendix A). The driller then switched to a HQ core setup and was able to advance the boring through what we interpret to be very dense boulders and cobbles with gravel and sand to a depth of approximately 20 feet. At 20 feet, the boring encountered a loose well-graded gravel with sand to 25 feet. The boring then encountered loose to medium dense, well-graded sand with gravel to a depth of approximately 38 feet. Poorly-graded sand with silt and gravel were encountered from 38 feet to the termination of the boring at 41.5 feet. The boring was terminated at this depth due to plugging of the core barrel from heaving sand conditions.

At the end of each 5-foot long core run, a standard penetration test was performed using a 2-inch outside diameter split spoon sampler to obtain blowcounts and retrieve samples. Field measured uncorrected standard penetration test “N” values are graphed on the boring logs.

However, the large diameter samplers are non-standard tests and the “N” values are not graphed on the boring logs, although the blowcounts for each 6-inch interval are reported. Some gravel-sized materials were also recovered inside the inner core barrel after each run, but were considered highly disturbed and likely washed of fine material from circulation of the drilling fluid. Due to the low recovery in the split spoon samples and the use of this atypical drilling/sampling procedure, the subsurface conditions noted on the logs should be considered highly interpretive.

Boring BH16-02 on the north side of Tom Miner Creek encountered dense, poorly-graded gravel and cobbles with silt, and sand from the ground surface to approximately 5 feet in depth, which we interpret to be embankment fill. From 5 to 8 feet, the boring encountered boulders and cobbles with gravel, sand, and a piece of wood. Auger refusal was encountered at approximately 8.5 feet in the first attempt, and the boring was abandoned and moved 5 feet to the north. The second attempt encountered auger refusal at 5.5 feet and the boring was moved

12 Subsurface Conditions

5 feet north again. The third attempt encountered refusal at 8.5 feet again, and the boring was terminated.

4.2 ROCK CREEK BORINGS

Borings BH16-03 and BH16-04 at Rock Creek generally encountered 8 to 11 feet of loose

(BH16-03) or very dense (BH16-04) sand and gravel with cobbles and boulders, which we interpreted to be embankment fill. Below the fill, the borings generally encountered layers of medium dense to very dense sands and gravels with various constituent quantities of silt, cobbles and boulders. These coarse-grained deposits were encountered to the full depth of

BH16-03 at 40.5 feet and to 62 feet in boring BH16-04. From 62 to 100.5 feet in BH16-04, a very stiff to hard sandy silt to silt with sand was encountered.

4.3 GROUNDWATER

At Tom Miner Creek Bridge, groundwater was not directly measured in boring BH16-01 prior to the introduction of drilling fluids at a depth of 8.5 feet due to switching to the casing advancer.

Boring BH16-02 did not encounter groundwater within the 8.5-foot exploration depth. Due to the highly permeable boulder/cobble layer encountered, we interpret the groundwater to be near the stream level at approximately 8.5 feet below the road surface, which we correlate to an approximate elevation of 5040.5 feet.

At Rock Creek Bridge, groundwater was encountered at the time of drilling at 17 feet and 18 feet below the ground surface in boring BH16-03 and BH16-04, respectively. These depths correspond to an estimated elevation of approximately 4989 feet and 4985 feet, respectively, assuming ground surface elevations obtained from the topographic survey at the boring locations measured relative to site features.

It should be noted that these groundwater measurements were taken during the summer and that groundwater and soil moisture conditions should be expected to fluctuate with adjacent stream levels, precipitation, nearby irrigation, and other seasonal factors.

Foundation Analysis and Recommendations 13

5 FOUNDATION ANALYSIS AND RECOMMENDATIONS

5.1 BRIDGE LAYOUT AND FOUNDATION CONSIDERATIONS

The proposed bridges will be identical 52-foot long, voided, prestressed slab superstructures.

Spread footings, Geosynthetic Reinforced Soil–Integrated Bridge System (GRS-IBS) and driven piles are the foundation types that were considered for this site.

The cost of driven piles would be high compared to the GRS-IBS option. The boulders and cobbles encountered in the borings would create difficult driving conditions and could result in misalignment or damage to the piling. These site conditions increase the risk of costly contract modifications and time delays for driven pile foundations on this project.

Spread footings and GRS-IBS are both shallow foundation alternatives. A conventional concrete spread footing foundation was considered but not chosen because a GRS-IBS will be more a more flexible system, have faster construction, and cost less. A typical cross-section through a GRS-IBS abutment is shown in Figure 5-1. GRS-IBS technology consists of closely spaced layers of geosynthetic reinforcement and compacted granular backfill and segmental retaining wall unit (SRWU) facing to create a reinforced soil foundation, abutment, and integrated approach for the bridge. The application of GRS-IBS has several advantages. The system is easy to design and inexpensive to construct. It can be quickly built in variable weather conditions with semi-skilled labor and equipment and can easily be modified in the field.

GRS-IBS is more flexible compared to other foundation alternatives during seismic events. The

GRS-IBS system integrates the superstructure into the abutment and approach embankment and thereby eliminates the bump at the end of the bridge that typically occurs with deep foundations.

Based on these considerations, GRS-IBS abutments are the recommended foundation type for this project.

Figure 5-1 Typical GRS-IBS Cross-Section (Adams, et al. 2011)

14 Foundation Analysis and Recommendations

5.2 DESIGN LOADS AND BEARING RESISTANCE

WFLHD Structural Engineer, Sara Loftus, provided the bridge foundation loads per abutment via email on May 25, 2017, summarized in Table 5-1. These loads are the same for both bridges.

Table 5-1 Final Bridge Design Loads

Load Type

Unfactored

Load (kips)

Service I Limit State Strength I Limit State

Load

Factor

(γ)

Factored

Load

(kips)

Load

Factor

(γ)

Factored

Load

(kips)

Dead load of superstructure and substructure (DC)

214 1.0 214 1.25 267

Dead load of wearing surface (DW) 14 1.0 14 1.50 21

Vehicular live load (LL) 145 1.0 145 1.75 254

Total 373 - 373 - 542

The superstructure will be set directly on top of the beam seat of the GRS-IBS abutment. The bearing bed reinforcement under the beam seat consists of closely spaced reinforcement to shed the loads. The calculated service limit state and strength limit state bearing loads at the top of the GRS-IBS abutment were calculated to be 3.3 ksf and 4.8 ksf, respectively, which is typical allowable values of 4 ksf and 6 ksf, respectively. This is based on a minimum beam seat width of 4 feet, although up to 5 feet is allowed in the plans to account for differences in batter.

5.3 DESIGN SOIL AND GEOTEXTILE PARAMETERS

Table 5-2 shows the soil parameters used in the GRS-IBS analysis. The bottom of the reinforced soil foundation (RSF) for the GRS-IBS will bear at elevation 978.5 on the project datum. This is below the upper layer of sandy silt and silty sand encountered in the subsurface investigation test pits and borings. The RSF will bear on the underlying relatively clean sand and gravel layer.

Table 5-2 Soil Parameters Used for GRS-IBS Design

Property Units

Foundation

Soil

Retained

Soil

Reinforced

Soil

RSF

Soil

Unit Weight pcf 125 125 115 115

Friction Angle deg 34 32 38 38

Cohesion pcf 0 0 0 0

Maximum Particle Size in. - - 1.5 -

The design was completed assuming the geotextile will be a woven geotextile with an ultimate tensile strength of at least 4800 lb/ft and tensile strength at 2 percent strain of at least 1000 lb/ft.

Foundation Analysis and Recommendations 15

5.4 GRS-IBS LAYOUT

The bridge layout was dictated by the hydraulic conditions in order to provide adequate clearance across the full channel width, below the bottom of the superstructure, and provide adequate embedment of the foundations for scour protection.

The height of the GRS-IBS with SRWU facing (measured from the beam seat to the scour elevation) will be approximately 9.9 feet at Abutment 1 and 9.0 feet at Abutment 2 for Tom

Miner Creek Bridge, and approximately 11.8 feet at Abutment 1 and 11.0 feet at Abutment 2 for

Rock Creek Bridge. These heights are the approximate minimum heights since the bridge decks have 3 percent superelevation. The reinforced soil foundation (RSF) will extend 2.5 feet below the base of the GRS-IBS abutment.

The GRS-IBS abutment will be 39.1 feet wide and the wing wall will extend 15 feet back at a 90 degree angle from the abutment face. The RSF limits will extend 2.5 feet horizontally outside the limits of the facing.

The main geotextile reinforcement lengths in the GRS-IBS will be 11 feet in length for all abutments. The main reinforcement layers are installed between subsequent layers of CMU blocks with a vertical spacing not exceeding 8 inches. The bearing bed zone, directly below the beam seat, will include 5 additional geotextile layers at mid-block height, each 7 feet in length, resulting in vertical spacing no greater than 4 inches between subsequent layers.

The integrated approach zonewill include 2 layers of geotextile reinforcement evenly spaced 8 inches vertically starting at the bottom of the beam elevation to the provide a seamless transition from the approach fill to the bridge deck. Each layer wraps back behind the end of the beams with a 4-foot-long tail.

GRS-IBS abutments using CMU blocks typically specify that the top 3 rows of hollow blocks are filled with concrete and rebar to tie them together. Since this project is specified for SRWUs with shear connectors and grouting of SRWU units is more difficult to perform depending on the manufacturer’s void shape, it is our opinion that grouting the upper 3 rows is not necessary on this project. Half height caps should be used and a polyurethane construction adhesive used to bond them to the top of the abutments and wingwalls.

16 Construction Considerations

6 CONSTRUCTION CONSIDERATIONS

6.1 EXCAVATION

The proposed GRS-IBS abutments will likely bear in the cobble/boulder layer at Tom Miner

Creek and in silty sand with gravel layers at Rock Creek. Excavation in the cobble/boulder layer, and even in the dense silty sand with gravel layers, will be difficult and may require very large equipment and/or hydraulic breakers. Excavation of boulders may result in subgrade voids that will require replacement with foundation fill or choker material to provide a level subgrade prior to construction of the RSF.

6.2 DEWATERING

Groundwater is expected at or above the elevation of the RSF excavations. A major challenge for this project will be the constructability of the RSF and GRS-IBS abutments in the coarse and highly permeable cobbles/boulder layers expected at Tom Miner. Rock Creek’s medium dense to dense silty sand with gravel layer should be more manageable from a typical sump-and-pump dewatering scenario, although disturbance of the subgrade from flowing water is also a risk. It is possible that a RSF could be constructed under a few feet of water, provided that a clean coarse aggregate, such as revet mattress rock or a suitable riprap is used in combination with a highly permeable geotextile. Shoring and dewatering should be designed with these considerations in mind. A cofferdam or slurry trench may be needed to dewater the excavation.

6.3 GRS-IBS CONSTRUCTION

The fundamental component of the GRS-IBS system is closely spaced layers of geotextile reinforcement with well-compacted granular backfill. Careful attention should be given to the installation of the first row of blocks. Since all other courses of block are built off the first row, it is essential to ensure that the bottom row is level and even for construction. If larger rock is used in the RSF, a choker material should be used to provide a leveling pad for the first row of

SRWUs.

It is highly recommended that the contractor reviews the following resources that provide further details on successful construction of GRS-IBS abutments.

FHWA provides a GRS-IBS construction video located at the following website:

http://www.fhwa.dot.gov/everydaycounts/technology/grs_ibs/multimedia.cfm

This construction video also can be viewed on the FHWA's YouTube channel at:

http://www.youtube.com/user/USDOTFHWA#p/a/u/0/w_5WFoAdoUw

The construction video follows the guidance outlined in the GRS-IBS Implementation

Guide, FHWA-HRT-11-026, dated January 2011, which is available at the following website:

http://www.fhwa.dot.gov/publications/research/infrastructure/structures/11026/index.cfm

Limitations 17

7 LIMITATIONS

This report was prepared to provide subsurface investigation results and geotechnical recommendations for the proposed Tom Miner Creek Bridge and Rock Creek Bridge foundations. Professional judgments 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 away from the borings. The observed water levels and/or conditions indicated on the logs are as recorded at the time of the exploration. The water levels and/or conditions may vary considerably, with season/time, changes in climate, rainfall, and other factors and are otherwise dependent on the duration of, and methods used in, and interpretations made from the exploration program.

If soil conditions are encountered during construction 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.

References 19

8 REFERENCES

AASHTO LRFD Bridge Design Specifications, Seventh Edition (2014 with 2015 and 2016 interim revisions) American Association of State Highway and Transportation Officials, Washington, D.C.

Berg, Richard B., Jeffrey D. Lonn, and William W. Locke (1999, map revised 9/08), Geologic

Map of the Gardiner 30’ x 60’ Quadrangle, South-Central Montana, Montana Bureau of Mines and Geology, Open File No. 387.

Kavazanjian, and others (2011), LRFD Seismic Analysis and Design of Transportation

Geotechnical Features and Structural Foundations, GEC No. 3, FHWA-NHI-032.

Neighorn, Jim (2016), Tom Miner Creek and Rock Creek Bridges Hydraulics TS&L Report, dated, December 29, 2016, U.S. Department of Transportation, Federal Highway

Administration, Western Federal Lands Highway Division.

U.S. Geological Survey, USGS Earthquake Hazards Program website, 2008 Interactive

Deaggregations, http://geohazards.usgs.gov/deaggint/2008/, accessed December, 2014

U.S. Geological Survey, USGS Earthquake Hazards Program website, U.S. Seismic Design

Maps, http://earthquake.usgs.gov/designmaps/us/application.php, accessed November 13, 2016.

U.S. Geological Survey and Montana Bureau of Mines and Geology, 2006, Quaternary fault and fold database for the United States, accessed November 12, 2016, from USGS web site:

http://earthquakes.usgs.gov/hazards/qfaults/.

Western Regional Climate Center (2017), Cooperative Climatological Data Summaries, Gardiner, Montana (243378): http://www.wrcc.dri.edu/cgi-bin/cliMAIN.pl?mt3378, accessed

June 5, 2017.

APPENDIX A

Site Photographs

Photo A-2, Upstream side of Tom Miner Creek Bridge facing southeast.

Photo A-1, Tom Miner Creek Bridge facing south.

Photo A-4, Tom Miner Creek viewed from the bridge facing southeast downstream.

Photo A-3, Tom Miner Creek viewed from the bridge facing west upstream.

Photo A-6, Rock Creek Bridge facing north.

Photo A-5, Undermined north abutment on Tom Miner Creek Bridge.

Photo A-8, View of Rock Creek channel facing east downstream .

Photo A-7, View of Rock Creek channel facing west upstream.

Photo A-10, View of damaged Rock Creek Bridge southwest abutment, facing west.

Photo A-9, Rock Creek Bridge facing west upstream.

Photo A-12, Vertical crack in the southeast wing wall.

Photo A-11, Damaged southwest wing wall with ~22-inch gap and two wrapped-cable braces.

Photo A-13, Vertical crack in Rock Creek Bridge northwest wingwall.

Photo A-14, Drilling for Boring B16-01 at Tom Miner Creek Bridge.

Photo A-15, Destroyed casing advancer bit on the left from boring BH16-01.

APPENDIX B

Boring Location Plans

3 1

N

Old Ye llowston e Trai l S

N

BH 16-02

BH 16-01

Existing bridge

Proposed bridge

KEERC RENI

M

M O

T

W O

L F

Line to be constructed

BH16-03

BH16-04

K

E E

R C

K C

O R

W O

L F

Existing bridge

Proposed bridge

BORE LOCATIONS

ROCK CREEK BRIDGE

BORE LOCATIONS

TOM MINER CREEK BRIDGE

STATE PROJECT

NUMBER

SHEET

I n t_ ft

D c m y fi le s p w p r o d u c ti o n d m t-a .d g n

MT PARK 63(1)

P

M

N o v e m b e r

C h e c k e d b y

D e s ig n e d b y

Line to be constructed

END PROJECT

104+90.00 (TM02)

101+20.00 (TM02)

BEGIN PROJECT

200+00.00 (RC02)

BEGIN PROJECT

END PROJECT

203+50.00 (RC02)

APPENDIX C

Field Classifications for Soil and Rock Unified Soil Classification System

Boring Logs B16-01 to B16-04

(6" = 33%)

50/1" (18" = 100%)

50/3"

(4" = 44%)

(0" = 0%)

S-1

S-2

S-3

S-4

Poorly-Graded GRAVEL and COBBLES with silt and sand (6" minus rounded to subrounded), dense, brown, damp.

(Fill)

SIlty GRAVEL with sand (GM), very dense, brown, moist.

Auger refusal at 8 feet. Switch to casing advancer. Loss of circulation.

BOULDERS and COBBLES with gravel and sand, very dense, multi-colored, wet

Casing advancer bit destroyed at 10.3 feet. Switch to HQ core barrel with SPT sampling at 5-foot intervals. Loss of circulation. 0 RQD. 37 minute core run from 10.3 to 15.3'.

Approx. 24 inches of gravel recovered up to 6 inches long.

15 minute core run from 15.3 to 20 feet. No SPT recovery, but approx. 12" core recovery of 3" minus rounded gravel.

Dense blowcounts. Loss of circulation. 0 RQD.

6.0

8.0

20.0

RECOVERY (%)

0 50

FIELD "N" VALUE

FIELD

BLOW

COUNT

(Recovery)

ELEVATION: 5049' [Est. from Topo]

D E

P T

H ft

E

LE

V ft)

Sheet 1 of 3

BORING LOG (US Customary Units)

S A

M P

LE

DRILLING METHODS:

DATE FINISHED:

TOTAL DEPTH: 41.5' (BOTTOM ELEV: 5007.5')

RQD (%)

AFTER DRILLING

Casing Advancer

2" OD Split Spoon (SPT)3" OD Split Spoon (D&M)

HQ Rock Core

AT COMPLETION

G R

A P

H

IC

L O

G

DESCRIPTION

HSA, Casing Adv., HQ Core

103+55, 10'LT

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

16.0

18.0

20.0

5049.0

5047.0

5045.0

5043.0

5041.0

5039.0

5037.0

5035.0

5033.0

5031.0

5029.0

"N" value not graphed for non-standard, large diameter samplersNOTES:

BORING BH16-01

COMPANY:

F ile

: C :\M

Y F

IL

E

S \E

R

IX

\0

P R

O

JE

C T

S \M

T \M

T P

A R

K

3( 1)

T O

M M

IN

E

R C

R E

E K

R O

A D

\L O

G S

A N

D L

A B

\T O

M M

IN

E

R L

O G

S .G

J

Li b:

C

U

S E

R S

\P U

B

LI

C \D

O C

U M

E N

T S

\B E

N T

LE

Y

\G

IN

T \L

IB

R

A R

IE

S

\F H

W A

LI

B

R A

R Y

.G

LB

ri nt ed : 1

1/

/2

Hollow Stem Auger

SK Geotech LOGGER: Eric Lim

P. Cloudy, 70-85 F

DATE STARTED:

0.0

FEDERAL HIGHWAY ADMINISTRATION

VANCOUVER, WASHINGTON

GEOTECHNICAL SECTION

Clayton Larsen

WEATHER:

5.5'

PROJECT: Tom Miner Creek Road Capital Improvements Project

Automatic - Efficiency 81%

WATER CONTENT (%)

8.5'

WATER LEVELS

HAMMER:

WHILE DRILLING

DRILLER:

DRILL: CME-75

D E

P T

H ft

6/21/2016

S A

M P

LE

R

6/22/2016

STATION, OFFSET:

(2" = 11%)

(3" = 17%)

(3" = 17%)

(0" = 0%)

S-5

S-6

S-7

S-8

Well-graded GRAVEL with sand, loose, gray-brown, wet. 25 minute core run from 20 to 25 feet. Loss of circulation. 0

RQD.

Well-graded SAND with gravel, loose to medium dense, gray-brown, wet. Sand is coarse, angular.

12 minute core run from 25 to 30 feet. 0 RQD.

10 minute core run from 30 to 35 feet. 0 RQD.

7 minute core run from 35 to 35 feet. 0 RQD.

Poorly-graded SAND with silt and gravel (SP-SM), medium dense, brown, wet.

25.0

38.0

RECOVERY (%)

0 50

FIELD "N" VALUE

FIELD

BLOW

COUNT

(Recovery)

ELEVATION: 5049' [Est. from Topo]

D E

P T

H ft

E

LE

V ft)

Sheet 2 of 3

BORING LOG (US Customary Units)

S A

M P

LE

DRILLING METHODS:

DATE FINISHED:

TOTAL DEPTH: 41.5' (BOTTOM ELEV: 5007.5')

RQD (%)

AFTER DRILLING

Casing Advancer

2" OD Split Spoon (SPT)3" OD Split Spoon (D&M)

HQ Rock Core

AT COMPLETION

G R

A P

H

IC

L O

G

DESCRIPTION

HSA, Casing Adv., HQ Core

103+55, 10'LT

20.0

22.0

24.0

26.0

28.0

30.0

32.0

34.0

36.0

38.0

40.0

5029.0

5027.0

5025.0

5023.0

5021.0

5019.0

5017.0

5015.0

5013.0

5011.0

5009.0

"N" value not graphed for non-standard, large diameter samplersNOTES:

BORING BH16-01

COMPANY:

F ile

: C :\M

Y F

IL

E

S \E

R

IX

\0

P R

O

JE

C T

S \M

T \M

T P

A R

K

3( 1)

T O

M M

IN

E

R C

R E

E K

R O

A D

\L O

G S

A N

D L

A B

\T O

M M

IN

E

R L

O G

S .G

C

U

S E

R S

\P U

B

LI

C \D

O C

U M

E N

T S

\B E

N T

LE

Y

\G

IN

T \L

IB

R

A R

IE

S

\F H

W A

LI

B

R A

R Y nt ed : 1

1/

/2

Hollow Stem Auger

SK Geotech LOGGER: Eric Lim

P. Cloudy, 70-85 F

DATE STARTED:FEDERAL HIGHWAY ADMINISTRATION

VANCOUVER, WASHINGTON

GEOTECHNICAL SECTION

Clayton Larsen

WEATHER:

5.5'

PROJECT: Tom Miner Creek Road Capital Improvements Project

Automatic - Efficiency 81%

WATER CONTENT (%)

8.5'

WATER LEVELS

HAMMER:

WHILE DRILLING

DRILLER:

DRILL: CME-75

D E

P T

H ft

6/21/2016

S A

M P

LE

R

6/22/2016

(6" = 33%)

S-9

Poorly-graded SAND with silt and gravel, medium dense, brown, wet.

Boring terminated at 41.5 feet on 6/22/16 due to plugging of core barrel. Groundwater levels were obscured by addition of coring fluids, and are estimates based on the adjacent stream level. Water at 5.5 feet immediately after removing augers. Boring backfilled with bentonite chips.

41.5

RECOVERY (%)

0 50

FIELD "N" VALUE

FIELD

BLOW

COUNT

(Recovery)

ELEVATION: 5049' [Est. from Topo]

D E

P T

H ft

E

LE

V ft)

Sheet 3 of 3

BORING LOG (US Customary Units)

S A

M P

LE

DRILLING METHODS:

DATE FINISHED:

TOTAL DEPTH: 41.5' (BOTTOM ELEV: 5007.5')

RQD (%)

AFTER DRILLING

Casing Advancer

2" OD Split Spoon (SPT)3" OD Split Spoon (D&M)

HQ Rock Core

AT COMPLETION

G R

A P

H

IC

L O

G

DESCRIPTION

HSA, Casing Adv., HQ Core

103+55, 10'LT

40.0

42.0

44.0

46.0

48.0

50.0

52.0

54.0

56.0

58.0

60.0

5009.0

5007.0

5005.0

5003.0

5001.0

4999.0

4997.0

4995.0

4993.0

4991.0

4989.0

"N" value not graphed for non-standard, large diameter samplersNOTES:

BORING BH16-01

COMPANY:

F ile

: C :\M

Y F

IL

E

S \E

R

IX

\0

P R

O

JE

C T

S \M

T \M

T P

A R

K

3( 1)

T O

M M

IN

E

R C

R E

E K

R O

A D

\L O

G S

A N

D L

A B

\T O

M M

IN

E

R L

O G

S .G

C

U

S E

R S

\P U

B

LI

C \D

O C

U M

E N

T S

\B E

N T

LE

Y

\G

IN

T \L

IB

R

A R

IE

S

\F H

W A

LI

B

R A

R Y nt ed : 1

1/

/2

Hollow Stem Auger

SK Geotech LOGGER: Eric Lim

P. Cloudy, 70-85 F

DATE STARTED:FEDERAL HIGHWAY ADMINISTRATION

VANCOUVER, WASHINGTON

GEOTECHNICAL SECTION

Clayton Larsen

WEATHER:

5.5'

PROJECT: Tom Miner Creek Road Capital Improvements Project

Automatic - Efficiency 81%

WATER CONTENT (%)

8.5'

WATER LEVELS

HAMMER:

WHILE DRILLING

DRILLER:

DRILL: CME-75

D E

P T

H ft

6/21/2016

S A

M P

LE

R

6/22/2016

(5" = 28%)

(5" = 28%)

S-1

S-2

Poorly-graded GRAVEL and COBBLES with silt and sand, rounded to subrounded, 12"-minus in auger cuttings, dense, brown, damp (Fill)

BOULDERS and COBBLES with gravel and sand, chunk of wood in sampler.

Auger refusal at 8.5 feet. Boring terminated and moved 5 feet north.

Auger refusal at 5.5 feet on second attempt. Boring terminated and moved 5 feet north.

Boulders from 3 to 5 feet and auger refusal at 8.5 feet.

Boring terminated and abandoned on 6/22/16. No groundwater encountered at time of drilling.

5.0

8.5

FIELD

BLOW

COUNT

(Recovery)

ELEVATION: 5049' [Est. from Topo]

D E

P T

H ft

E

LE

V ft)

Sheet 1 of 1

BORING LOG (US Customary Units)

S A

M P

LE

DRILLING METHODS:

DATE FINISHED:

TOTAL DEPTH: 8.5' (BOTTOM ELEV: 5040.5')

AFTER DRILLING

3" OD Split Spoon (D&M)

Hollow Stem Auger

AT COMPLETION

G R

A P

H

IC

L O

G

DESCRIPTION

HSA, Casing Adv., HQ Core

104+29, 8'RT

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

16.0

18.0

20.0

5049.0

5047.0

5045.0

5043.0

5041.0

5039.0

5037.0

5035.0

5033.0

5031.0

5029.0

"N" value not graphed for non-standard, large diameter samplersNOTES:

BORING BH16-02

COMPANY:

F ile

: C :\M

Y F

IL

E

S \E

R

IX

\0

P R

O

JE

C T

S \M

T \M

T P

A R

K

3( 1)

T O

M M

IN

E

R C

R E

E K

R O

A D

\L O

G S

A N

D L

A B

\T O

M M

IN

E

R L

O G

S .G

C

U

S E

R S

\P U

B

LI

C \D

O C

U M

E N

T S

\B E

N T

LE

Y

\G

IN

T \L

IB

R

A R

IE

S

\F H

W A

LI

B

R A

R Y nt ed : 1

1/

/2

SK Geotech LOGGER: Eric Lim

Clear, 80s F

DATE STARTED:

0.0

FEDERAL HIGHWAY ADMINISTRATION

VANCOUVER, WASHINGTON

GEOTECHNICAL SECTION

Clayton Larsen

WEATHER:

PROJECT: Tom Miner Creek Road Capital Improvements Project

Automatic - Efficiency 81%

WATER LEVELS

HAMMER:

WHILE DRILLING

DRILLER:

DRILL: CME-75

D E

P T

H ft

6/22/2016

S A

M P

LE

R

6/22/2016

(1" = 6%)

(6" = 33%)

(6" = 33%)

50/2"

(3" = 37%)

50/4" (3" = 76%)

S-1

S-2

S-3

S-4

S-5

S-6

Well-graded GRAVEL with silt and sand, scattered cobbles and boulders, loose, brown, damp (Fill)

Rough drilling throughout. Auger moved the rig over 1 foot on boulder.

Becomes moist.

Boulders/Cobbles. Hard drilling / obstruction at 8 to 9 feet.

Switch from center drag bit to tri-cone bit. Grind on the obstruction for 5 mintues, auger walks to the south again.

Silty SAND (SM) with scattered gravel/cobbles/boulders, medium dense, brown, moist.

Rock fragments in sampler.

Well-Graded GRAVEL with silt and sand (GW-GM), very dense, brown, moist

Very hard drilling. 30 minutes to auger from 15 to 20 feet.

Silty SAND with gravel (SM), medium dense, brown, wet.

Occasional gravel and cobble drilling action.

8.0

9.0

14.0

19.0

FIELD "N" VALUE

FIELD

BLOW

COUNT

(Recovery)

ELEVATION: 5006' [Est. from Topo]

D E

P T

H ft

E

LE

V ft)

Sheet 1 of 3

BORING LOG (US Customary Units)

S A

M P

LE

DRILLING METHODS:

DATE FINISHED:

TOTAL DEPTH: 40.5' (BOTTOM ELEV: 4965.5')

LIQUID LIMIT

AFTER DRILLING

3" OD Split Spoon (D&M)

Hollow Stem Auger

2" OD Split Spoon (SPT)

AT COMPLETION

G R

A P

H

IC

L O

G

DESCRIPTION

HSA, Casing Adv., HQ Core

200+52, 11'RT

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

16.0

18.0

20.0

5006.0

5004.0

5002.0

5000.0

4998.0

4996.0

4994.0

4992.0

4990.0

4988.0

4986.0

"N" value not graphed for non-standard, large diameter samplersNOTES:

BORING BH16-03

COMPANY:

F ile

: C :\M

Y F

IL

E

S \E

R

IX

\0

P R

O

JE

C T

S \M

T \M

T P

A R

K

3( 1)

T O

M M

IN

E

R C

R E

E K

R O

A D

\L O

G S

A N

D L

A B

\T O

M M

IN

E

R L

O G

S .G

C

U

S E

R S

\P U

B

LI

C \D

O C

U M

E N

T S

\B E

N T

LE

Y

\G

IN

T \L

IB

R

A R

IE

S

\F H

W A

LI

B

R A

R Y nt ed : 1

1/

/2

SK Geotech LOGGER: Eric Lim

Clear, 80s F

DATE STARTED:

0.0

FEDERAL HIGHWAY ADMINISTRATION

VANCOUVER, WASHINGTON

GEOTECHNICAL SECTION

Clayton Larsen

WEATHER:

PROJECT: Tom Miner Creek Road Capital Improvements Project

Automatic - Efficiency 81%

WATER CONTENT (%)

17'

WATER LEVELS

HAMMER:

WHILE DRILLING

DRILLER:

DRILL: CME-75

D E

P T

H ft

6/24/2016

S A

M P

LE

R

6/24/2016

STATION, OFFSET:

PLASTIC LIMIT

(13" = 72%)

(7" = 39%)

(10" = 56%)

(10" = 56%)

S-7

S-8

S-9

S-10

Silty SAND with gravel (SM), medium dense, brown, wet.

Occasional gravel and cobble drilling action.

Rough drilling from 22 to 23 feet.

Well-graded SAND with silt and gravel, medium dense, brown, wet

Silty SAND with gravel, dense, brown, wet.

27.0

33.0

FIELD "N" VALUE

FIELD

BLOW

COUNT

(Recovery)

ELEVATION: 5006' [Est. from Topo]

D E

P T

H ft

E

LE

V ft)

Sheet 2 of 3

BORING LOG (US Customary Units)

S A

M P

LE

DRILLING METHODS:

DATE FINISHED:

TOTAL DEPTH: 40.5' (BOTTOM ELEV: 4965.5')

LIQUID LIMIT

AFTER DRILLING

3" OD Split Spoon (D&M)

Hollow Stem Auger

2" OD Split Spoon (SPT)

AT COMPLETION

G R

A P

H

IC

L O

G

DESCRIPTION

HSA, Casing Adv., HQ Core

200+52, 11'RT

20.0

22.0

24.0

26.0

28.0

30.0

32.0

34.0

36.0

38.0

40.0

4986.0

4984.0

4982.0

4980.0

4978.0

4976.0

4974.0

4972.0

4970.0

4968.0

4966.0

"N" value not graphed for non-standard, large diameter samplersNOTES:

BORING BH16-03

COMPANY:

F ile

: C :\M

Y F

IL

E

S \E

R

IX

\0

P R

O

JE

C T

S \M

T \M

T P

A R

K

3( 1)

T O

M M

IN

E

R C

R E

E K

R O

A D

\L O

G S

A N

D L

A B

\T O

M M

IN

E

R L

O G

S .G

C

U

S E

R S

\P U

B

LI

C \D

O C

U M

E N

T S

\B E

N T

LE

Y

\G

IN

T \L

IB

R

A R

IE

S

\F H

W A

LI

B

R A

R Y nt ed : 1

1/

/2

SK Geotech LOGGER: Eric Lim

Clear, 80s F

DATE STARTED:FEDERAL HIGHWAY ADMINISTRATION

VANCOUVER, WASHINGTON

GEOTECHNICAL SECTION

Clayton Larsen

WEATHER:

PROJECT: Tom Miner Creek Road Capital Improvements Project

Automatic - Efficiency 81%

WATER CONTENT (%)

17'

WATER LEVELS

HAMMER:

WHILE DRILLING

DRILLER:

DRILL: CME-75

D E

P T

H ft

6/24/2016

S A

M P

LE

R

6/24/2016

STATION, OFFSET:

(9" = 50%)

Silty SAND with gravel, dense, brown, wet.

Boring completed at 40.5 feet bgs on 6/24/16. Groundwater measured at 17 feet bgs at time of drilling.

40.5

FIELD "N" VALUE

FIELD

BLOW

COUNT

(Recovery)

ELEVATION: 5006' [Est. from Topo]

D E

P T

H ft

E

LE

V ft)

Sheet 3 of 3

BORING LOG (US Customary Units)

S A

M P

LE

DRILLING METHODS:

DATE FINISHED:

TOTAL DEPTH: 40.5' (BOTTOM ELEV: 4965.5')

LIQUID LIMIT

AFTER DRILLING

3" OD Split Spoon (D&M)

Hollow Stem Auger

2" OD Split Spoon (SPT)

AT COMPLETION

G R

A P

H

IC

L O

G

DESCRIPTION

HSA, Casing Adv., HQ Core

200+52, 11'RT

40.0

42.0

44.0

46.0

48.0

50.0

52.0

54.0

56.0

58.0

60.0

4966.0

4964.0

4962.0

4960.0

4958.0

4956.0

4954.0

4952.0

4950.0

4948.0

4946.0

"N" value not graphed for non-standard, large diameter samplersNOTES:

BORING BH16-03

COMPANY:

F ile

: C :\M

Y F

IL

E

S \E

R

IX

\0

P R

O

JE

C T

S \M

T \M

T P

A R

K

3( 1)

T O

M M

IN

E

R C

R E

E K

R O

A D

\L O

G S

A N

D L

A B

\T O

M M

IN

E

R L

O G

S .G

C

U

S E

R S

\P U

B

LI

C \D

O C

U M

E N

T S

\B E

N T

LE

Y

\G

IN

T \L

IB

R

A R

IE

S

\F H

W A

LI

B

R A

R Y nt ed : 1

1/

/2

SK Geotech LOGGER: Eric Lim

Clear, 80s F

DATE STARTED:FEDERAL HIGHWAY ADMINISTRATION

VANCOUVER, WASHINGTON

GEOTECHNICAL SECTION

Clayton Larsen

WEATHER:

PROJECT: Tom Miner Creek Road Capital Improvements Project

Automatic - Efficiency 81%

WATER CONTENT (%)

17'

WATER LEVELS

HAMMER:

WHILE DRILLING

DRILLER:

DRILL: CME-75

D E

P T

H ft

6/24/2016

S A

M P

LE

R

6/24/2016

STATION, OFFSET:

(9" = 50%)

(11" = 61%)

(8" = 44%)

(14" = 78%)

(18" = 100%)

S-1

S-2

S-3

S-4

S-5

S-6

Silty SAND with gravel to silty GRAVEL with sand, scattered cobbles and boulders, dense to very dense, brown, damp to moist, piece of wood (Fill). Rough drilling throughout.

More gravel.

Becomes moist.

Silty GRAVEL with sand (GM), medium dense, brown, damp-moist.

Poorly-graded SAND with silt and gravel (SP-SM), dense, brown, damp-moist

Silty SAND with gravel, dense, brown, wet

11.0

13.5

18.0

20.0

FIELD "N" VALUE

FIELD

BLOW

COUNT

(Recovery)

ELEVATION: 5003' [Est. from Topo]

D E

P T

H ft

E

LE

V ft)

Sheet 1 of 6

BORING LOG (US Customary Units)

S A

M P

LE

DRILLING METHODS:

DATE FINISHED:

TOTAL DEPTH: 100.5' (BOTTOM ELEV: 4902.5')

LIQUID LIMIT

AFTER DRILLING

3" OD Split Spoon (D&M)

Hollow Stem Auger

2" OD Split Spoon (SPT)

AT…