CSP16R36493_Stevens_Ranch_Bridge_FINAL_11MAR16.pdf

20162974.001A/CSP16R36493 Page 1 of 1 March 11, 2016 © 2016 Kleinfelder www.kleinfelder.com

4815 List Drive, Unit 115, Colorado Springs, CO 80919-3340 p | 719.632.3593 f | 719.632.2648

March 11, 2016 Kleinfelder Project No. 20162974.001A/CSP16R36493

Mr. Rob Thompson, PE HDR, Inc.

1670 Broadway, Suite 3400 Denver, Colorado 80202 rob.thompson@hdrinc.com

Subject: Geotechnical Evaluation Report

ND FTFW CLSA RTE 12 BR

Stevens Ranch Bridge Replacement J. Clark Salyer National Wildlife Refuge Near Minot, North Dakota Federal Highway Administration Central Federal Lands Highway Division Task Order Number: DTFH68-12-D-00013/0069

Dear Mr. Thompson:

The attached report presents the results of our Geotechnical Evaluation performed for the proposed Stevens Ranch Bridge replacement project at the J. Clark Salyer National Wildlife Refuge near Minot, North Dakota. Our work consisted of a subsurface exploration, laboratory testing, engineering analyses, and preparation of this report.

We appreciate this opportunity to be of service to you, and look forward to future endeavors. If you have any questions regarding this report or need additional information or services, please contact the undersigned at (719) 632-3593.

Respectfully submitted, KLEINFELDER

Brysen T. Mustain, PG (WY) Adam. D. Tschida, PE (ND) Project Geologist Principal Engineer

Hai Ming Lim, PE (OK) Geotechnical Engineer

BTM/ADT/HML/jkw

Enclosures http://www.kleinfelder.com/ mailto:phil.hahn@hdrinc.com

20162974.001A/CSP16R36493 March 11, 2016

GEOTECHNICAL EVALUATION REPORT

ND FTFW CLSA RTE 12 BR

STEVENS RANCH BRIDGE REPLACEMENT

J. CLARK SALYER NATIONAL WILDLIFE REFUGE

NEAR MINOT, NORTH DAKOTA

FEDERAL HIGHWAY ADMINISTRATION

CENTRAL FEDERAL LANDS HIGHWAY DIVISION

TASK ORDER NUMBER: DTFH68-12-D-00013/0069

KLEINFELDER PROJECT # 20162974.001A

MARCH 11, 2016

Copyright 2016 Kleinfelder All Rights Reserved

ONLY THE CLIENT OR ITS DESIGNATED REPRESENTATIVES MAY USE THIS DOCUMENT AND ONLY FOR THE SPECIFIC

PROJECT FOR WHICH THIS REPORT WAS PREPARED.

mailto:phil.hahn@hdrinc.com

20162974.001A/CSP16R36493 Page ii of iii March 11, 2016

TABLE OF CONTENTS

PAGE

1 INTRODUCTION

1.1 GENERAL

1.2 PROJECT DESCRIPTION

1.3 PURPOSE AND SCOPE

2 FIELD EXPLORATION AND LABORATORY TESTING

2.1 FIELD EXPLORATION

2.2 LABORATORY TESTING

2.2.1 Geotechnical Laboratory Testing

2.2.2 Analytical Laboratory Testing

3 SITE CONDITIONS

3.1 SURFACE

3.2 GEOLOGIC REVIEW AND DISCUSSION

3.3 SEISMICITY

3.4 SUBSURFACE

3.5 GROUNDWATER

4 CONCLUSIONS AND RECOMMENDATIONS

4.1 GEOTECHNICAL FEASIBILITY OF PROPOSED CONSTRUCTION

4.2 CONSTRUCTION CONSIDERATIONS

4.2.1 General

4.2.2 Site Preparation

4.2.3 Excavation Characteristics

4.2.4 Structural Fill Requirements

4.2.5 Fill Placement and Compaction

4.2.6 Utility Trench Backfill

4.2.7 Construction in Wet or Cold Weather

4.2.8 Construction Testing and Observation

4.2.9 Surface Drainage

4.3 DEEP FOUNDATION SYSTEMS

4.3.1 Driven Piles

4.3.2 Estimated Foundation Movement

4.3.3 Lateral Resistance of Deep Foundations

4.4 WING WALLS

4.4.1 Shallow Foundation Systems

4.4.2 Earth Pressure and Sliding Resistances

4.5 CORROSION POTENTIAL

4.5.1 Chemical Sulfate Susceptibility and Concrete Type

5 ADDITIONAL SERVICES

6 LIMITATIONS

7 REFERENCES

8 ABBREVIATIONS DEFINED

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FIGURES

1 Exploration Location Plan and Vicinity Map

APPENDICES

A Boring Logs B Geotechnical Laboratory Test Results C Analytical Laboratory Test Results D Site Photos E Important Information About This Geotechnical Engineering Report

TABLE OF CONTENTS

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1 INTRODUCTION

1.1 GENERAL

This report presents the results of our Geotechnical Evaluation performed for the proposed

Stevens Ranch Bridge Replacement project on the J. Clark Salyer National Wildlife Refuge near

Minot, North Dakota. Figure 1 shows the general location of the project. Our investigation was performed for HDR, Inc. (HDR), and was authorized by Mr. Philip Hahn, PE.

This report includes our recommendations relating to the geotechnical aspects of project design and construction. The conclusions and recommendations stated in this report are based on the subsurface conditions found at the locations of our exploratory borings at the time our exploration was performed. They also are subject to the provisions stated in the report sections titled

Additional Services and Limitations. Our findings, conclusions, and recommendations should not be extrapolated to other areas or used for other projects without our prior review. Furthermore, they should not be used if the site has been altered, or if a prolonged period has elapsed since the date of the report, without Kleinfelder’s prior review to determine if they remain valid.

1.2 PROJECT DESCRIPTION

Based on our understanding, the project site is located at mile 7.4 along Route 012 (a.k.a. 3rd

Avenue NE) within the J. Clark Salyer National Wildlife Refuge in McHenry County near Minot, North Dakota. The existing single-span, single-lane bridge is approximately 24-feet long. We understand that a single-span pre-cast, pre-stressed concrete box beam superstructure (post-tensioned to provide additional stability) with integral stub abutments constructed on HP 12x53 driven steel H-piles is planned. The new bridge will be a replacement bridge, located at the same location of the existing bridge. According to HDR, the factored superstructure reaction per each abutment is about 485 kips. The total factored abutment load including the superstructure reaction, abutment self-weight and wingwall self-weight is 566 kips.

Retaining walls are not planned, but wing walls at the abutments are planned. Other construction related activities are anticipated to include minor site grading. If the type of construction is to vary significantly from the above description, Kleinfelder should be notified to revise our recommendations, as required.

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1.3 PURPOSE AND SCOPE

The purpose of our investigation was to explore and evaluate subsurface conditions near the location of the proposed replacement bridge structure and, based on the conditions found, to develop recommendations relating to the geotechnical aspects of project design and construction.

Our conclusions and recommendations in this report are based on analysis of the data from our field exploration, laboratory tests, and our experience with similar soil and geologic conditions.

Kleinfelder’s scope of services included:

• Reconnaissance to observe surface conditions at the project site and to locate the exploratory borings.

• Notification of the One-Call Center of North Dakota to identify underground utility lines near the boring locations prior to our drilling.

• Coordinating with J. Clark Salyer National Wildlife Refuge personnel for right-of-way access adjacent to the existing bridge.

• Drilling of two exploratory borings, at the approximate locations presented on Figure 1, at the proposed location of the bridge replacement (borings located approximately 10-feet behind existing bridge abutment location);

• Laboratory testing of selected samples obtained during the field exploration to evaluate relevant physical and engineering properties of the soil.

• Evaluation and engineering analysis of the field and laboratory data collected to develop our geotechnical conclusions and recommendations.

• Preparation of this report, which includes a description of the proposed project, a description of the surface and subsurface site conditions found during our investigation, our conclusions and recommendations as to foundation design, other related geotechnical issues, and appendices which summarize our field and laboratory investigations.

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2 FIELD EXPLORATION AND LABORATORY TESTING

2.1 FIELD EXPLORATION

The field exploration program was performed on November 5 and 6, 2015, and included drilling two borings as summarized in Table 1:

Table 1 Summary of Field Exploration Program

Boring Designation

Approximate Boring Latitude

Approximate Boring Longitude

Approximate Total Depth of Exploration [feet] below ground surface

B-1 48.54163° -100.51411° 66

B-2 48.54153° -100.51421° 101

1. Latitude/Longitude obtained by handheld GPS, and therefore locations are limited to the accuracy of the GPS unit (estimated to be on the order of a 10-ft radius).

The exploratory borings were advanced at the approximate locations indicated on Figure 1 using a

CME-75 truck-mounted drill rig equipped with 6-inch outside-diameter, continuous-flight, hollow-stem auger and 3-inch diameter mud rotary drilling techniques.

The borings were logged by visually identifying and field classifying soils in general accordance with ASTM International Standard D2488 and the Unified Soil Classification System (USCS).

Upon completion of laboratory testing, soil classifications were further evaluated in general accordance with ASTM D2487 and are presented on the boring logs in Appendix A.

Subsurface samples were obtained during exploration using a thin-walled Shelby tube pushed into the strata, or a standard split-spoon SPT sampler (1.375-inch I.D.) driven into the strata with blows from an automatic 140-pound hammer falling through a 30-inch drop. The blows required to drive the SPT sampler into the strata are recorded on the logs. These blow counts are an indication of the relative density or consistency of the strata. The samples were packaged in jars and sealed in the field to reduce moisture loss and disturbance, and were returned to our Colorado Springs, Colorado office for laboratory testing.

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Appendix A to this report includes the individual boring logs describing the subsurface conditions encountered and an approximate profile of subsurface conditions at the boring locations. The lines defining boundaries between soil types on the logs are based on drill rig behavior and interpolation between samples, and are therefore approximate. Transition between soil types may be abrupt or may be gradual.

2.2 LABORATORY TESTING

2.2.1 Geotechnical Laboratory Testing

Geotechnical laboratory tests were performed on select soil samples to estimate their relative engineering properties. The following tests were performed in general accordance with recognized standards:

• Description and Identification of Soils (Visual-Manual Procedure);

• Classification of Soils for Engineering Purposes;

• Natural Density and Moisture Content Test;

• Sieve Analysis of Fine and Coarse Aggregates;

• Liquid Limit, Plastic Limit, and Plasticity Index of Soils;

• Time-Rate Consolidation, and;

• Unconfined Compressive Strength.

Results of the laboratory tests are included in Appendix B of this report. Selected test results are also shown on the boring logs in Appendix A.

2.2.2 Analytical Laboratory Testing

Analytical testing performed for this project included:

• pH;

• Resistivity;

• Redox;

• Sulfide Content;

• Water Soluble Chlorides, and;

• Water Soluble Sulfates.

Results of the analytical laboratory tests are included in Appendix C of this report. Selected test results are also shown on the boring logs in Appendix A.

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3 SITE CONDITIONS

3.1 SURFACE

The existing bridge is located along Route 012 over an active tributary of the Souris River within the J. Clark Salyer National Wildlife Refuge. The existing bridge is approximately 24-feet in length and is comprised of a single-span structure. Existing fill, approximately 4-feet in thickness, was encountered from the ground surface at both abutments on either side of the bridge.

Grasses, plants, and trees exist along the channel banks and surrounding area. In the vicinity of the bridge structure, the ground surface is generally flat with a slight slope down towards the southeast.

In general, the existing roadway is located within a national wildlife refuge. No other existing structures are present in the immediate site area. The land adjacent to the roadways is generally undeveloped. Route 012 has a gravel surface.

3.2 GEOLOGIC REVIEW AND DISCUSSION

Prior to drilling, the geology of the site was evaluated by reviewing published geologic maps, including the USGS Geologic Map of the Geology of the Souris River area (east half), North Dakota

(Lemke, 1960). A portion of the geologic map is presented below.

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Published mapping indicates that the site consists primarily of dune sand (Qd), alluvium deposits comprised of sand, silt, and clay (Qal), and deposits of glacial Lake Souris comprised of sand and silt (Qgl). Samples collected during the subsurface investigation generally agree with the published geologic mapping. Claystone and sandstone bedrock was encountered in the borings underlying the units described above.

3.3 SEISMICITY

Based upon the geologic setting, subsurface soil conditions, and low seismic activity in this region, liquefaction is not expected to be a hazard at the site. The subsurface soil profiles correspond best with 2009 AASHTO Site Class E. No active faults are mapped by USGS within 5-mile radius of the site. The intermediate values from 2009 AASHTO Guide used to obtain the design parameters are provided below in Tables 2 and 3.

Table 2 Design Acceleration for Short Period

Ss Fa

Site Class E 0.031 2.5

SS = The mapped spectral accelerations for short periods (U.S. Geological Survey Web Page, 2016) Fa = Site coefficient from Table 3.4.2.3-1, 2009 AASHTO

Table 3 Design Acceleration for 1-Second Period

S1 Fv

Site Class E 0.011 3.5 S1 = The mapped spectral accelerations for 1-second period (U.S. Geological Survey Web Page, 2016) Fv = Site coefficient from Table 3.4.2.3-2, 2009 AASHTO

The peak ground acceleration (PGA) for this site is 0.013 g.

Based on estimated SDS and SD1 values for the site, the Hazard Level for this site is classified as I according to Section 6.3 of FHWA-NHI-11-032, GEC No. 3, August 2011. An evaluation of liquefaction in soils near the surface is not required based on the Hazard Level.

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3.4 SUBSURFACE

As determined by visual observation, subsurface exploration, and supplementary laboratory testing, the subsurface materials on this site consisted mainly of sand fill deposits underlain by native sand and clay, and claystone and sandstone bedrock. The general subsurface conditions encountered at the project site are described in more detail below:

Existing Fill Fill materials comprised of silty sand with gravel to poorly graded sand with gravel, each presumably associated with construction of backfill behind the existing abutments, was encountered at the ground surface and extended to a depth of approximately 6-feet below the ground surface in both borings. The fill materials were dark brown to brown, and moist. We are not aware of the origins or level of compaction of these fills, which are therefore considered “undocumented.”

Native Sand, Clay, and Silt Layers with variable thickness of native sand, clay, and silt materials were encountered underlying the fill unit described above and extended to depths of approximately 57½ and 62½-feet below the ground surface in borings B-1 and B-2, respectively. A thin layer of gray, moist silt was encountered from about 14 to 17½-feet below the ground surface in boring B-1. Field penetration testing (blow counts) indicated the consistency of the clay was generally very soft to firm and relative density of the sand was generally very loose to dense. Unconfined compressive strength testing performed on samples of the native clay exhibited approximate compressive strengths of 1800, 2300, and

3700 pounds per square foot (psf) at high strains.

Bedrock Weathered claystone was encountered below the units described above at depths of approximately

62½ and 57½-feet below the existing ground surface and extended to the maximum depth explored of approximately 66-feet below the ground surface in boring B-1 and to a depth of approximately

68-feet below the ground surface in boring B-2, respectively. Field penetration testing (blow counts) indicated the weathered claystone was firm to hard.

Relatively unweathered claystone and sandstone bedrock was encountered underlying the weathered claystone in boring B-2 at a depth of approximately 68-feet and extended to the maximum depth explored of approximately 101-feet. Field penetration testing (blow counts)

20162974.001A/CSP16R36493 Page 8 of 24 March 11, 2016 indicated the claystone and sandstone was hard. The claystone, as well as the sandstone, was generally gray in color and moist.

More detailed descriptions of subsurface conditions encountered at individual exploration locations are presented on the exploratory boring logs included in Appendix A. Additional lab test results are presented in Appendix B.

3.5 GROUNDWATER

Groundwater was encountered in borings B-1 and B-2 during drilling at depths of approximately 25 and 20-feet, respectively, below the ground surface. Drilling fluid was introduced into boring B-2 for the mud rotary drilling methods, thus affecting groundwater level measurements in B-2 after the completion of drilling. The location of the project site within an active river tributary indicates that surface water will be a significant construction issue.

Contingencies for encountering surface water infiltration, groundwater, and associated dewatering issues should be considered during excavation and earthwork operations of the bridge replacement.

The subsurface moisture conditions at this site will fluctuate seasonally and with changes in precipitation. Significant variations in the depths and locations as to where groundwater may be encountered are potentially influenced by the Souris River tributary. Soil moisture levels and groundwater levels commonly vary over time and space depending on seasonal precipitation, irrigation practices, land use, and runoff conditions. These conditions and the variations that they create often are not apparent at the time of field investigation. Accordingly, the soil moisture and groundwater data in this report pertain only to the locations and times at which exploration was performed. They can be extrapolated to other locations and times only with caution.

It should be noted that Kleinfelder did not install groundwater-monitoring piezometers, nor have we performed a hydrologic evaluation for this site. The seasonal variability in subsurface moisture conditions at this site has not been measured.

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4 CONCLUSIONS AND RECOMMENDATIONS

4.1 GEOTECHNICAL FEASIBILITY OF PROPOSED CONSTRUCTION

Kleinfelder found no subsurface conditions during this investigation that would preclude construction of the project essentially as planned. The major geotechnical section headings and locations of the associated geotechnical design recommendations/parameters that are provided in subsequent sections of this report are summarized below:

Earthwork and Construction Considerations

Earthwork and construction considerations for site preparation, structural fill and compaction specifications, drainage, and materials are presented in Section 4.2.

Deep Foundation Systems

Geotechnical design parameters for driven steel H-piles for the proposed structure are presented in Section 4.3. Deep foundation systems are designed in general accordance with AASHTO

LRFD, 6th Edition.

Shallow Foundation System

Geotechnical design parameters for a shallow spread footing foundation system for wing walls of the proposed structure are presented in Section 4.4. Shallow foundation systems are designed in general accordance with AASHTO LRFD, 6th Edition.

Our geotechnical design and construction recommendations for site preparation, foundations, and other related construction topics are provided in the following sections.

4.2 CONSTRUCTION CONSIDERATIONS

4.2.1 General

Unless other federal or local agency requirements or specifications apply, construction should be performed in conformance with the Standard Specifications for Construction of Roads and

Bridges on Federal Highway Projects, FP-14. The following sections provide recommendations associated with the proposed bridge construction.

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4.2.2 Site Preparation

Begin site work by stripping vegetation and other deleterious materials now present at the ground surface within the subject site. This applies both to areas to be filled and areas to be cut. Remove the stripped materials for offsite disposal in accordance with Section 204.14 of FP-14 or, if appropriate, stockpile them for later use. Areas to receive fill should be stripped of soft earth materials until a firm subgrade is exposed, as evaluated by the geotechnical engineer.

Where applicable, prior to placement of structural elements (i.e. beneath foundations/pavements, etc.), processing of the subgrade should be performed per Section 303 of FP-14. Per subsection

204.09 of FP-14, the subgrade should be scarified to a minimum depth of 6-inches, and surface irregularities removed. The subgrade surface should be moisture conditioned to within a range of -2 to +2 percent of optimum moisture content for clay soil with liquid limit less than 40, sand, gravel or silt, or at a moisture content of 0 to +3 percent of the optimum moisture content for clay soils with liquid limit greater than 40, and compacted to a minimum 95% (AASHTO T180 or T99, see Section 204.11 of FP-14) of the laboratory maximum dry density.

Where encountered, undocumented fill soils should be overexcavated at least two feet below the bottom of proposed structural elements, replaced with imported structural fill, and compacted following the recommendations provided in the following sections.

It should be noted that if any structural elements are being constructed during adverse weather conditions (e.g. heavy precipitation) this can result in unstable subgrade conditions. Any soft and/or wet areas exposed during the excavation process may need to be stabilized prior to placement of new fill to create a stable construction platform. The method and extent of stabilization will depend on the actual conditions encountered, and the more appropriate method of stabilization will likely be best determined in the field at the time of excavation.

Typical stabilization methods may include aggregate base course (or similar) stabilization utilizing geo-grid such as Tensar BX1200, and rock stabilization to form a stable base on which to place the pavement section. Installation typically includes placement of the geo-grid directly on subgrade with about 12 to 18-inches of aggregate base course above the grid. Rock aggregate size and depth of mitigation will vary depending on actual conditions encountered and would require adjustment during construction. Rock stabilization may be achieved by over-excavation and/or placement of an initial 12 to 18-inch-thick lift of 12-inch-minus, 3-inch-plus, well graded, 20162974.001A/CSP16R36493 Page 11 of 24 March 11, 2016 angular rock fill. The more angular and well graded the rock is, the more effective it will be. This fill should be densified with large equipment, such as a self-propelled sheeps-foot or a large loader, until no further deflection is noted. Additional lifts of rock may be necessary to achieve adequate stability.

4.2.3 Excavation Characteristics

We anticipate that excavation of the on-site overburden soils can be performed with conventional earthmoving equipment.

All excavations must comply with the Section 204 of FP-14 and any applicable local, state and federal safety regulations, and particularly with the excavation standards of the Occupational Safety and Health Administration (OSHA). Construction site safety, including excavation safety, is the sole responsibility of the Contractor as part of the contractor’s overall responsibility for the means, methods and sequencing of construction operations.

For planning purposes, the near-surface soils on this site may be classified as Type C materials using OSHA criteria. OSHA requires that unsupported cuts be laid back to ratios no steeper than 1½H:1V (horizontal to vertical) up to 20-feet in height. In general, we believe that these slope inclinations will be temporarily stable under unsaturated conditions. Where groundwater seepage occurs, flatter slopes will be appropriate. The actual determination of soil type and allowable sloping must be made in the field by the contractor’s OSHA-qualified “competent person.”

4.2.4 Structural Fill Requirements

Structural fill refers to material that is appropriate for placement beneath structure components, embankment fill, and pavement subgrade. Based on the results of our subsurface explorations and laboratory testing, the on-site granular soils are appropriate for this use provided any particles greater than 3-inches are removed. If imported fill is required to meet proposed site grades, it should consist of a non-expansive, mainly granular material meeting the requirements presented in Section

704.07 of FP-14 (Select Borrow), shown in Table 4, below.

A sample of any proposed imported structural fill should be submitted to our office for review and testing at least 3 days prior to stockpiling at the site. The native subgrade to receive structural fill should be prepared in accordance with Section 4.2.2.

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Table 4 Imported Structural Fill Criteria (SELECT BORROW)

Gradation Requirements (Table 704-1, Section 704.07, FP-14)

Standard Sieve Size Percent Passing

3-inch 100

1-inch 70 - 100

No. 4 30 - 70

No. 200 0.0 – 5.0

Plasticity Requirements (Atterberg Limits, AASHTO T-89, Method A)

Liquid Limit 30 max

A representative of Kleinfelder should perform testing and observation of the subgrade structural fill placement.

4.2.5 Fill Placement and Compaction

Fill materials should be placed in horizontal lifts compatible with the type of compaction equipment being used, moisture conditioned, and compacted in accordance with following criteria:

Table 5 Fill Placement Criteria

Fill Location Material Type

Percent Compaction1

(AASHTO T-180 or T-99, see Section

204.11 of FP-14)

Moisture Content

Site Grading Fill;

Utility Trenches

On-site Soils or Imported Structural Fill

(see Section 4.2.4) 95 minimum -0% to +3% of optimum

Wing Wall Backfill;

Embankment Fill

Imported Structural Fill (see Section 4.2.4) 95 minimum -2% to +2% of optimum

1. In non-structural, non-pavement, or landscaped areas, the compaction specification may be reduced to 92 percent.

Fill should be placed in level lifts not exceeding 6-inches in loose thickness, and compacted to the specified percent compaction to produce a firm and stable surface. If field density tests indicate the required percent compaction has not been obtained or the surface is pumping/deflecting under construction traffic, the fill material should be reconditioned as

20162974.001A/CSP16R36493 Page 13 of 24 March 11, 2016 necessary and re-compacted to the required percent compaction before placing any additional material.

Fill against any foundation walls should be properly placed and compacted as recommended herein. Backfill should be mechanically compacted in layers (6 to 8-inches maximum loose lift thickness). Care should be taken when placing backfill so as not to damage the walls.

Compaction of each lift adjacent to and near the walls should be accomplished with hand-operated tampers or other lightweight compactors. Over-compaction may cause excessive lateral earth pressures, which could result in wall movement, and potentially damage the walls. If required, wall designs may need to consider increased lateral pressures during construction/compaction.

4.2.6 Utility Trench Backfill

Backfill material for utility trenches (if present) should be essentially free of plant matter, organic soil, debris, trash, other deleterious matter and rock particles larger than 2-inches. However, backfill material in the “pipe zone” (from the trench floor to 1-foot above the top of pipe) should not contain rock particles larger than 1-inch. Strictly observe any requirements specified by the utility agency for bedding and pipe-zone fill. In general, backfill above the pipe zone in utility trenches should be placed in lifts of 6 to 8-inches and compacted using power equipment designed for trench work to the specifications recommended in Section 4.2.4 of this report.

4.2.7 Construction in Wet or Cold Weather

No grading fill, structural fill, or other fill should be placed on frosted or frozen ground, nor should frozen material be placed as fill. Frozen ground should be allowed to thaw or be completely removed prior to placement of fill. If earthwork is performed during the winter months when freezing is a factor, a good practice is to cover the compacted fill with a “blanket” of loose fill to help prevent the compacted fill from freezing.

During construction, grade the site so that surface water can drain readily away from the excavation areas. It is very important to avoid ponding of water in or near excavations. Promptly pump out or otherwise remove water that accumulates in excavations or on subgrades, and allow these areas to dry out before resuming construction. Use berms, ditches, and similar means to prevent storm water from entering the work area and to convey it off site efficiently.

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Do not install concrete elements on frozen soil. Frozen soil should either be removed from beneath the concrete elements altogether, or thawed and re-compacted. To avoid soil freezing, minimize the amount of time passing between excavation/subgrade preparation and pouring concrete. Use blankets, soil cover, or heating as required to prevent the foundation subgrade from freezing.

4.2.8 Construction Testing and Observation

Enough field testing and construction observation should take place under the direction of a qualified geotechnical engineer to support that engineer’s professional opinion as to whether the earthwork does or does not substantially conform to the recommendations in this report.

Furthermore, the opinions and conclusions of a geotechnical report are based on interpretation of a limited amount of information obtained from the field exploration. It is therefore not uncommon to find that actual site conditions differ somewhat from those indicated in the report.

The geotechnical engineer should remain involved throughout the project to evaluate such differing conditions as they appear, and to modify or add to the geotechnical recommendations as necessary.

4.2.9 Surface Drainage

Positive drainage away from all planned structures will be essential to the long-term performance of the structures and pavements. Surface drainage should be created such that water is diverted off the site and away from backfill areas of adjacent foundations.

4.3 DEEP FOUNDATION SYSTEMS

We understand that the bridge structure will likely be supported by HP 12x53 driven steel H-piles.

The recommendations for the deep foundation system are provided in the following sections.

4.3.1 Driven Piles

We understand that the proposed bridge will be supported on driven steel HP 12x53 piles. The total factored abutment load including the superstructure reaction, abutment self-weight and wingwall self-weight is 566 kips, and it is assumed that each abutment will be supported on four driven piles. Based on this estimation, the factored load on each pile is on the order of approximately 142 kips. We recommend that driven piles bear within the CLAYSTONE as identified on our boring logs (approximate depth of 68 feet below existing ground surface). Care should be taken to ensure that the driven steel H-piles penetrate any weathered claystone, and end-bear within the underlying CLAYSTONE bedrock.

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Piles should be installed in accordance with the latest version of Section 551 of FP-14. Since piles will be driven into bedrock, it is recommended that steel H-piles be driven with protective points to reduce the potential for damage to the pile during driving. The pile driving contractor should be given the opportunity to review the boring logs to assess the appropriate driving technique.

At the time of publishing this report, the pile driving equipment was unknown. Driven piles comprised of Grade 50 steel HP 12x53 H-piles driven 5-feet into the claystone bedrock can be designed for a combined nominal end bearing and skin friction resistance of 308 kips per pile. A resistance factor of 0.52 (with 5 piles or less at each abutment) should be applied to the nominal resistance to calculate the factored geotechnical resistance of the driven piles. The factored geotechnical resistance of the driven pile is estimated at 160 kips. Hammers used for the driving should be selected based on Section 551.05 of FP-14. The actual pile capacity should be confirmed during the pile driving in accordance with Section 551.13 of FP-14. We recommend that the Pile Driving Analyzer (PDA) method to be used.

Wave equation and drivability analysis were not performed at this time since the hammer information is not available. After the preliminary hammer type is selected, it is recommended that Kleinfelder be provided with the information and perform wave equations and drivability analyses using computer program (GRL-WEAP). The wave equation and drivability analyses will evaluate the adequacy of the selected hammer for the pile driving, and the compression and tension stresses in the piles during driving. The analyses will also provide information to be used for the quality control monitoring.

Piles likely will be used in a line along the foundation. This is not a true group condition of piles to provide for eccentricities in loading. However, if the piles are placed close together, the group capacity of such a line of piles will be less than the summation for the individual pile capacities.

Analysis of group capacity depends on the geometry of the group. We recommend that minimum spacing of the piles be twice the average pile diameter or 1.75 times the diagonal dimension of the pile cross-section, but no less than 24-inches. Vertical piles should not vary more than 2% from the plumb position. Please contact Kleinfelder for an appropriate reduction factor when a tentative pile layout is available.

Continuous observation of the pile driving operations should be performed by Kleinfelder as a representative of the owner. A continuous log should be maintained on the number of blows per

20162974.001A/CSP16R36493 Page 16 of 24 March 11, 2016 foot required to drive each pile. Driving should be completed without interruption (except for splicing) and without jetting or pre-drilling unless the geotechnical engineer has been contacted for further recommendations.

4.3.2 Estimated Foundation Movement

Deep foundations designed in accordance with our recommendations should not produce long-term movements less than 1-inch or differential movements of more than about ½ -inches. If loads different than those provided are expected, please contact Kleinfelder to review the loadings and provide additional analysis if necessary.

4.3.3 Lateral Resistance of Deep Foundations

It is our understanding that the lateral load analyses will be performed by the structural engineer using the software program LPile developed by Ensoft, Inc. This program analyzes a single pile considering deflection as a function of the design loads, foundation construction, and subsurface conditions. Table 6, below, provides LPile input parameters for the foundation soils and rock.

Table 6 LPILE Parameters

Depth (ft)

P-Y Curve Model

Effective Unit

Weight (pcf)

Undrained Cohesion

(psf)

Friction Angle (deg)

Strain Factor, ε50

Soil modulus, k

(pci)

Boring B-1 and B-2

0 to 3 Sand n/a n/a n/a n/a n/a

3 to 18 Stiff Clay without Free Water

125 480 n/a 0.02 n/a

18 to 33 Sand 125 (AG)*

62.6 (BG)* 0 30 n/a 25 (AG)*

20 (BG)*

33 to 53 Stiff Clay without Free Water

62.6 (BG)* 1,100 n/a 0.007 n/a

53 to 68

Stiff Clay without Free

Water (Weathered Claystone)

67.6 (BG)* 3,700 n/a 0.005 n/a

68 to 85

Stiff Clay without Free

Water (Claystone)

67.6 (BG)* 8,000 n/a 0.004 n/a

*AG = Above Groundwater, BG = Below Groundwater

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It is recommended that the lateral support from the soil within 6-feet of final design grade be ignored due to potential loss of support from frost penetration or other shallow ground disturbance. In addition, sloping grades or the influence of other structures should be included in the lateral pile analyses. The values provided are based on the existing subsurface conditions and were estimated, or calculated, based on generally accepted engineering correlations.

If the foundations are spaced closer than five times the diameter center to center, lateral resistances should be scaled by an appropriate multiplier from Table 10.7.2.4-1 of AASHTO

LRFD, which is summarized in Table 7, below.

Table 7 LPILE P-Multiplier for Multiple Row Pile Groups

Pile Center to Center Spacing P-Multipliers, Pm

Row 1 Row 2 Row 3 & Greater

3D 0.8 0.4 0.3

5D 1.0 0.85 0.7

4.4 WING WALLS

4.4.1 Shallow Foundation Systems

We understand that the abutment wing walls will likely be supported on a shallow footing foundation system. Design parameters for a spread footing foundation are presented in more detail below.

• Spread footing foundations constructed on at least two feet of imported structural fill as described in Section 4.2.2 may be designed for a maximum factored soil bearing resistance of 1,500 psf. All foundations should be proportioned as much as practicable to minimize differential settlement.

• The actual foundation size, thickness, and reinforcement should be determined by a qualified structural engineer based on the soil bearing resistance and actual structural loads.

• We estimated total settlement for foundations placed on soils as discussed above would be about 1.5-inch or less with potential differential settlement of the order of ½ to ¾-inches.

• Shallow foundation elements in should have at least 6-feet of cover above the bottom of the foundation for frost protection, or that required by the local building code, whichever is greater.

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• Loose soil present within the foundation areas should be removed prior to placement of concrete.

• The foundation subgrade should be protected from wetting and drying prior to and after concrete placement until backfilling around the foundation elements has been completed.

Footings should be backfilled as soon as practical after concrete placement.

• A representative of Kleinfelder should observe all foundation excavations prior to placement of concrete and/or fill. Additionally, the placement and compaction of structural fill should be observed and tested by a representative of our firm.

4.4.2 Earth Pressure and Sliding Resistances

Wing walls will be subjected to lateral earth pressures. We recommend that imported granular fill materials to be placed within the retained zone behind the wing walls. The retained zone is defined as the wedge area at 1:1 (V:H) slope behind the walls from the heels of the wall footings.

The design and construction criteria presented below should be observed for earth retention systems on this site with flat backslopes.

Table 8 Lateral “Equivalent Fluid” Earth Pressure Parameter Summary

Parameter Imported Granular Structural Fill At-Rest1 65 pcf Active2 45 pcf

Passive2,3 375 pcf Coefficient of Sliding Friction4 0.29

Notes: 1. Retaining walls that are laterally supported (structurally restrained from rotation) can be expected to undergo only a slight amount of deflection. These walls should be designed for an “at-rest” lateral earth pressure.

2. Retaining structures which can deflect sufficiently to mobilize the full “active” earth pressure condition should be designed for an “active” lateral earth pressure.

3. Lateral loads may be resisted using the unfactored passive earth pressure. For passive resistance, a resistance factor (LRFD) of 0.5 should be used.

4. The above lateral earth pressures assume drained conditions behind the walls and a horizontal backfill surface. For sliding resistance of cast-in-place concrete on imported granular fill, a resistance factor of 0.80.

To prevent hydrostatic loading on the abutment walls, it is recommended that a perforated drain line be installed behind and at the base of the abutment walls. The drain line should be sloped to provide positive gravity drainage to a positive gravity outfall or weep holes. The drain line should be backfilled with free draining granular material extending vertically above the drain line to the

20162974.001A/CSP16R36493 Page 19 of 24 March 11, 2016

2-feet below the top of the wall. The granular section behind the wall should have a minimum width of 2-feet and should be encapsulated in a suitable filter fabric to minimize intrusion of fines.

A less-permeable clay cap comprising on-site soils should be placed above the free draining granular material to help mitigate infiltration of surface water.

The above lateral earth pressures do not account for traffic surcharge loading. A typical traffic surcharge load would comprise a 250 pounds per square foot (psf) pressure at the pavement surface. These earth pressures also assume drained conditions behind the walls and a horizontal backfill surface.

4.5 CORROSION POTENTIAL

Laboratory testing was completed to provide data regarding corrosivity of onsite soils. Our scope of services does not include corrosion engineering and, therefore, a detailed analysis of the corrosion test results is not included. A qualified corrosion engineer should be retained to review the test results and design protective systems that may be required.

Laboratory chloride concentration, sulfate concentration, sulfide concentration, pH, oxidation reduction potential, and electrical resistivity tests were performed on samples of onsite clay soils and claystone materials obtained during our field investigation. The results of the tests are included as Appendix C to this report and are summarized below in Table 9.

Table 9 Summary of Laboratory Soil Corrosivity Testing

Boring

No.

Sample

Depth

(ft)

Lithology pH

Water

Soluble

Chloride

Water

Soluble

Sulfate (%)

Sulfides Resistivity

(ohm-cm)

Redox

Potential, Eh (mv)

B-1 34.5 - 36 Clay 7.8 0.0011 0.010 Negative 1,218 260

B-2 79.5 - 81 Claystone 8.8 0.0044 0.010 Positive 501 196

Metal and concrete elements in contact with soil, whether part of a foundation system or part of a supported structure, are subject to degradation due to corrosion or chemical attack. Therefore, buried metal and concrete elements should be designed to resist corrosion and degradation based on accepted practices.

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The corrosivity test results indicate that the onsite soils and bedrock may be corrosive to uncoated steel, and protective measures may be required.

4.5.1 Chemical Sulfate Susceptibility and Concrete Type

The degradation of concrete or cement grout can be caused by chemical agents in the soil or groundwater that react with concrete to either dissolve the cement paste or precipitate larger compounds within the concrete, causing cracking and flaking. The concentration of water-soluble sulfates in the soils is a good indicator of the potential for chemical attack of concrete or cement grout. The American Concrete Institute (ACI) in their publication Guide to Durable Concrete (ACI

201.2R-08) provides guidelines for this assessment.

The concentration of water-soluble sulfates measured on subsurface materials submitted for testing represent a Class 0 exposure of sulfate attack on concrete exposed to the soils. ACI has no specific sulfate-resistance requirements for concrete in contact with these soils; Type I cement may be used for concrete in contact with the soils.

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5 ADDITIONAL SERVICES

Additional Kleinfelder services are not anticipated for this project beyond preparation of this report.

However, the following services are highlighted as they are critical to ensuring proper implementation of the recommendations provided through communication to designer and contractor, and verifying construction compliance with project plans and specifications.

• Review of plans and specifications to verify recommendations provided herein were properly incorporated into plans and specs.

• Pre-bid and pre-construction meetings to clarify recommendations and clear up any conflicts, misunderstandings, or ambiguities between the recommendations provided herein and the final plans and specs.

• The recommendations in this report depend on the assumption that an adequate program of testing and observation will be made during construction to verify compliance with our recommendations. These tests and observations may include, but not necessarily be limited to, the following:

o Observations and density testing during site preparation and earthwork;

o Observation and testing of subgrade preparation, and;

o Consultation as may be required during construction.

Adequate testing and observation is essential to successful and economical completion of a construction project. Testing and observation allow for verification that the recommendations are being followed. They also make it possible to identify new or changed conditions that could require modification of recommendations.

We understand the services above will be performed by HDR and/or CFLHD. Kleinfelder is happy to provide these services or assistance in support of these services as necessary.

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6 LIMITATIONS

The recommendations in this report are based on our field observations, laboratory testing, and our present understanding of the proposed construction. It is possible that subsurface conditions can vary between or beyond the points explored. If the conditions found during construction differ from those described in this report, please notify us immediately so that we can review our report in light of those conditions and provide supplemental recommendations as necessary. We should also review the report if the scope of the proposed construction, including the proposed loads or structure locations, changes from that described in this report.

Kleinfelder has prepared this report for the exclusive use of HDR, Inc. for the proposed Stevens

Ranch Bridge Replacement project in the J. Clark Salyer National Wildlife Refuge in McHenry

County near Minot, North Dakota. The report was prepared in substantial accordance with the generally accepted standards of practice for geotechnical engineering as exist in the site area at the time of our investigation. No warranty is expressed or implied. The recommendations in this report are based on the assumption that Kleinfelder will conduct an adequate program of construction testing and observation to evaluate compliance with our recommendations.

This report may be used only by the client and only for the purposes stated, within a reasonable time from its issuance, but in no event later than 3 years from the date of the report. Land or facility use, on and off-site conditions, regulations, or other factors may change over time, and additional work may be required with the passage of time. Based on the intended use of the report, Kleinfelder may require that additional work be performed and that an updated report be issued. Non-compliance with any of these requirements by the client or anyone else will release

Kleinfelder from any liability resulting from the use of this report by any unauthorized party and client agrees to defend, indemnify, and hold harmless Kleinfelder from any claim or liability associated with such unauthorized use or non-compliance.

20162974.001A/CSP16R36493 Page 23 of 24 March 11, 2016

7 REFERENCES

ASTM International. (2015) Annual Book of ASTM Standards.

Federal Highway Administration (2014). Standard Specifications for Construction of Roads and

Bridges on Federal Highway Projects – FP-14 U.S. Customary Units, U.S. Department of

Transportation, Federal Lands Highway.

Federal Highway Administration (2011). LRFD Seismic Analysis and Design of Transportation

Geotechnical Features and Structural Foundations, Pub. NO. FHWA-NHI-11-032, GEC No.

3, August 2011

Lemke, R.W., Geology of the Souris River area, North Dakota, 1960, scale 1:96,000

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8 ABBREVIATIONS DEFINED

AASHTO American Association of State Highway and Transportation Officials

ABC Aggregate Base Course

ASTM ASTM International

CFLHD Central Federal Lands Highway Division

FHWA Federal Highway Administration

FP-14 2014 FHWA Standard Specifications for Construction of Roads and Bridges on

Federal Highway Projects

H:V Horizontal to Vertical

OSHA Occupational Safety and Health Administration

USCS Unified Soil Classification System

20162974.001A/CSP16R36493 March 11, 2016 © 2016 Kleinfelder www.kleinfelder.com

FIGURE 1

EXPLORATION LOCATION PLAN AND VICINITY MAP

The information included on this graphic representation has been compiled from a variety of sources and is subject to change without notice. Kleinfelder makes no representations or warranties, express or implied, as to accuracy, completeness, timeliness, or rights to the use of such information. This document is not intended for use as a land survey product nor is it designed or intended as a construction design document. The use or misuse of the information contained on this graphic representation is at the sole risk of the party using or misusing the information.

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1. BASE MAP IMAGE CREATED FROM DATA COMPILED BY ArcGIS, IMAGE CREATED 11/11/2015.

2. VICINITY MAP CREATED FROM DATA COMPILED BY ArcGIS.

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