Geotech_Report-2014-1104.pdf

GEOTECHNICAL ENGINEERING EVALUATION

Proposed Replacement Shop Building National Bison Range Wildlife Refuge

Moiese, Montana

Prepared by Ryan M. Lewis, E.I.T.

James R. Thomasson, P.E.

STRATA

A Professional Services Corporation 5653 Alloy South

Missoula, MT 59801 P. 406.829.1600 F. 406.829.1610

Prepared for

Mr. Patrick Kiernan K-Con, Inc.

2728 Spruill Avenue Charleston, South Carolina 29405

November 4, 2014

NOTE: THIS REPORT IS FOR HISTORICAL

REFERENCE ONLY. IT IS NOT TO BE

USED AS A BASIS OF DESIGN. A NEW

REPORT IS TO BE PROVIDED BY THE

GENERAL CONTRACTOR FOR THE NEW

REPLACEMENT SHOP, FWS PROJECT

NUBMER 18-030.

5653 Alloy South, Missoula, Montana 59808 Phone.406.829.1600 Fax.406.829.1610 www.stratageotech.com

File: MI14094A

Mr. Patrick Kiernan K-Con, Inc.

RE: Geotechnical Engineering Evaluation

National Bison Range Wildlife Refuge

Moiese, Montana

Greetings Mr. Kiernan:

Strata, A Professional Services Corporation (STRATA) is pleased to provide this geotechnical engineering evaluation for the planned replacement shop building in the National Bison Range Wildlife Refuge near Moiese, Montana. We accomplished our evaluation to assess subsurface soil conditions beneath the site and provide geotechnical recommendations to assist project planning, design, and construction. STRATA performed our work in reference to the geotechnical standard of care as it exists at this time, in the Western Montana region.

This report summarizes our field evaluation and laboratory testing results, our engineering opinions, and geotechnical recommendations. We present subsurface conditions observed at the site in conjunction with soil engineering and construction characteristics herein. This report presents specific geotechnical information based on the subsurface conditions encountered during exploration, and our project understanding. We base our geotechnical recommendations on this understanding and they must be read and implemented in their entirety. Portions or individual sections of our report cannot be relied upon without the supporting text.

Our opinion is project construction success will depend upon the design team and contractor following our report recommendations, the contractor adhering to good construction practices, and the owner and/or contractor providing the necessary construction monitoring, testing, and geotechnical consultation to verify the work has been accomplished as recommended herein. We recommend you retain STRATA to provide monitoring, testing, and geotechnical consultation to verify the report recommendations are being followed during final design and construction. If we are not retained to provide geotechnical continuity, we cannot be responsible for designer or contractor errors, omissions, or report misinterpretations.

Geotechnical Engineering Evaluation

National Bison Range Wildlife Refuge

Moiese, Montana

PREPARED FOR:

Mr. Patrick Kiernan

K-Con, Inc.

PREPARED BY:

STRATA

A Professional Services Corporation 5653 Alloy South

Missoula, Montana 59808 Telephone 406.829.1600 Facsimile 406.829.1610

© 2014 by Strata, A Professional Services Corporation. All rights reserved.

TABLE OF CONTENTS

Page

INTRODUCTION

PROJECT UNDERSTANDING

FIELD AND LABORATORY EVALUATION

Site Exploration Laboratory Testing Subsurface Conditions

GEOTECHNICAL ANALYSES, FINDINGS AND RECOMMENDATIONS

Earthwork

Site and Subgrade Preparation Excavation Characteristics Structural Fill and Required Compaction Wet Weather/Wet Soil Construction Over-excavations and Soil Improvement Construction

Foundation Design Seismicity Liquefaction Potential

Concrete Slab-on-Grade Floors General Moisture Protection

Site Drainage Perimeter Foundation Drainage Considerations Site Grading and Surface Drainage

ADDITIONAL RECOMMENDED SERVICES

Geotechnical Design Continuity Plan and Specification Review Construction Observation and Testing

EVALUATION LIMITATIONS

REPORT TABLES

TABLE 1. STRUCTURAL FILL SPECIFICATIONS AND ALLOWABLE USE

FIGURE 1: VAPOR RETARDER FLOWCHART

REPORT PLATES & APPENDICES

Plate 1: Exploration Site Map Appendix A: Unified Soil Classification System (USCS) Exploration Logs Appendix B: Laboratory Test Results

5653 Alloy South, Missoula, Montana 59808 Phone.406.829.1600 Fax.406.829.1610

National Bison Range Wildlife Refuge

Moiese, Montana

INTRODUCTION

To accomplish our geotechnical engineering evaluation, we assessed subsurface soil conditions within the proposed project area outlined to us by K-Con, Inc. (K-Con) and prepared these specific geotechnical recommendations to assist project planning, design, and construction for the planned replacement shop building in the National Bison Range Wildlife Refuge (Bison Range) near Moiese, Montana. We accomplished the following tasks referencing our authorized proposal dated September 30, 2014:

1. STRATA contacted the public utility notification service to locate public utilities and Mr. Bob Rebarchik with the U.S. Fish and Wildlife Services (Fish and Wildlife) to locate private utilities.

2. STRATA subcontracted a backhoe and operator to accomplish four (4) exploratory test pits just outside the anticipated building foundation footprint corners. We advanced the test pits up to 10 feet beneath the ground surface. STRATA observed the test pits and described, classified and logged the subsurface conditions encountered referencing ASTM International (ASTM) D2487, Unified Soil Classification System (USCS). We obtained select subsurface soil samples for laboratory testing. STRATA loosely backfilled test pits level with the ground surface upon completion.

3. STRATA performed laboratory testing on select soil samples referencing ASTM International (ASTM) test procedures to help assist soil classification and to estimate soil engineering properties.

4. STRATA reviewed the subsurface conditions encountered, laboratory test results, and the proposed construction to develop geotechnical engineering recommendations for the following:

Earthwork

• Site and subgrade preparation

• Excavation characteristics

• Structural fill criteria and required compaction

• Wet weather/wet soil construction

• Over-excavations and Granular Soil Improvement Construction

Typical Shallow Foundation Design Criteria

• Confirmation of allowable foundation bearing pressure (1,500 psf)

• Foundation bearing pressure increase for transient loading

• Estimated total and differential foundation settlement

• Soil improvement requirements

• Coefficient of foundation base sliding friction (fs)

• Foundation frost embedment depth

• 2012 International Building Code (IBC) Site Class

Concrete Slab-on-Grade Design Criteria

• Minimum recommended slab support section

• Vapor retarder considerations

Proposed Replacement Shop Building; Moiese, Montana

• Concrete slab design and construction considerations

Site Drainage

• Perimeter site drainage

• Foundation and underslab drainage requirements

Additional Recommended Services

• Geotechnical design continuity

• Plan and specification review

• Geotechnical observation during construction

5. STRATA incorporated the above recommendations into this final geotechnical engineering evaluation report. We provided 3 hard copies and an electronic copy of our report including a site plan, exploration logs, and laboratory testing results.

PROJECT UNDERSTANDING

We base our project understanding on our telephone and electronic mail conversations with you and on-site discussion with Mr. Bob Rebarchik, the deputy project leader for the Bison Range.

We understand Fish and Wildlife plans to construct a replacement maintenance shop at the Bison

Range. The proposed shop will be constructed on currently unimproved scrub land and will consist of a pre-engineered metal building with a footprint measuring 55 feet by 100 feet. The building will have an eave height of 18 feet and will have interior offices and a mezzanine. Preliminary foundation design details indicate the building will likely be founded on a minimum 3-foot-deep perimeter footing design with an allowable soil bearing pressure of 1,500 pounds per square foot (psf). Enlarged pad footings will be located under steel structural column supports. Concrete slab-on-grade is expected to be 6-inches thick and reinforced with No. 4 rebar at 24 inches on center each-way.

FIELD AND LABORATORY EVALUATION

To provide geotechnical recommendations for the proposed project, we evaluated the property by performing exploration and laboratory testing as described in the following sections.

Site Exploration

STRATA evaluated subsurface conditions at the project site by observing four (4) test pit excavations advanced to depths up to 10 feet beneath the ground surface using a Deere 310SG backhoe equipped with a 30-inch-wide bucket and standard soil excavation teeth. Plate 1, Exploration Location Plan, provides approximate exploration locations documented in the field using a commercially available global positioning system (GPS) and confirmed by measuring from existing site features. We established exploration locations based on our discussions with you and Mr.

Rebarchik. STRATA personnel visually described, classified, and logged the subsurface conditions encountered referencing the USCS and obtained select soil samples for laboratory testing. Upon completion, we loosely backfilled test pits with excavated spoils placed approximately level with the surrounding ground surface. Appendix A provides exploratory test pit logs and a USCS explanation, which should be referenced to interpret soil terms used throughout this report and attachments.

Laboratory Testing

We tested select representative soil samples obtained during exploration to assess soil engineering characteristics through the individual laboratory tests listed below. We performed the following tests on samples collected at select depths and locations as noted on the exploration logs in Appendix A:

Natural Moisture Content Atterberg Limits Moisture-Density Relationship In Situ Unit Weight

STRATA accomplished the above laboratory test program referencing applicable ASTM test standards. STRATA will retain excess soil samples for 60 days following issuance of this report, unless we receive written notification to retain the samples for a longer time period.

Subsurface Conditions

Test pits encountered native silt throughout the entire soil profile to termination depths. The silt was tan to brown, firm to stiff, and moist.

We did not encounter groundwater during exploration. Based on our research of available well logs and exploration, groundwater is expected to exist in excess of 50 feet beneath the ground surface at the site, however, groundwater has the potential to vary with seasonal fluctuations in precipitation, irrigation, infiltration and project site developments. We did not encounter bedrock within the depths or locations explored.

Although soil conditions encountered in the locations explored were somewhat consistent with respect to soil type, exploratory excavations allow observation of a relatively small sample of the subsurface conditions at the site. Variations may exist between or beyond exploration locations.

These variations would not be apparent until construction. Where such variations exist, it may affect the opinions and recommendations presented in this report as well as construction timing and costs.

Therefore, we must be contacted to review the encountered conditions exposed during construction and revise our recommendations, if necessary.

GEOTECHNICAL ANALYSES, FINDINGS AND RECOMMENDATIONS

We present the following geotechnical considerations to assist project planning, design and construction for the proposed replacement shop building planned in the National Bison Range

Wildlife Refuge near Moiese, Montana. Our analyses, findings, and geotechnical recommendations are based on experience with similar soil and geologic conditions, our project understanding, and the results from fieldwork and laboratory testing. If project plans change, we request STRATA be notified to review the modification and revise our recommendations if necessary. Additionally, if unforeseen conditions are encountered during earthwork, STRATA should be contacted to review our recommendations and provide any necessary consultation, revision or modifications to the information contained herein.

Earthwork

Site and Subgrade Preparation

STRATA encountered soil containing moderate organics and vegetation within the upper 3 inches of the soil profile in the locations explored. We recommend all soil containing more than 5 percent organics and vegetation be removed below any planned improvement, structure or fill placement area to expose native soil.

Following topsoil removal and excavation to desired grades, and prior to structural fill or concrete placement, we recommend the stripped subgrade surface be scarified, moisture-conditioned and re-compacted to a depth of 8 inches. Recompacting the subgrade will require moisture-conditioning and soil processing. Such subgrade preparations can often help identify areas susceptible to subgrade pumping and rutting. After attempting moisture conditioning, remove pumping or rutting subgrade areas to a depth of 12 inches below the subgrade elevation, or to firm stable soil, whichever is greater. After the subgrade has been moisture-conditioned, compacted, and reviewed by STRATA, structural fill or concrete placement may commence.

Excavation Characteristics

Based on exploration results, we anticipate the native silt may be excavated using conventional soil excavation techniques. In general, slopes and excavations must be excavated, shored, or braced in accordance with the Occupational Safety and Health Administration (OSHA) regulations and local codes. Based on our exploration and laboratory testing, the native silt is generally classified as a “B” type soil according to OSHA requirements. As such, we recommend provisions be made to allow temporary excavations of any type and soil to be sloped back to at least

1H:1V (horizontal to vertical) when it remains in a moist condition. Surface water infiltration and construction vibrations may require much flatter, temporary slopes. Ultimately, the selected contractor is responsible for site safety and maintaining excavation stability.

Excavations must be planned carefully, allowing water collection points and utilizing conventional sumps and pumps to remove nuisance water from runoff or precipitation. If soil excavations are not immediately backfilled, they may degrade when exposed to runoff and require over-excavation and replacement with granular structural fill. We recommend construction activities and excavation backfilling be performed as rapidly as possible following excavation to reduce the potential for subgrades to degrade under construction traffic.

Structural Fill and Required Compaction

Place all soil fill for the development (with the exception of non-structural fill) as structural fill.

The native silt is not suitable for reuse as general structural fill and earthwork contractors must plan for its removal from the site. Table 1 below summarizes the recommended structural fill products and their allowable uses referencing the latest edition of the Montana Public Works Standard

Specifications (MPWSS).

Table 1. Structural Fill Specifications and Allowable Use

Soil Fill Product

Allowable Use Material Specifications

Non-Structural Fill

(Landscape Fill)

• Any area that will not contain structures (landscape areas).

• Soil classified as GP, GM, GW, GC SP, SM, SW, SC, CL, or ML according to the USCS.

• Soil may not contain particles larger than 12 inches in median diameter.

• Soil must be reasonably free from deleterious substances such as wood, metal, plastic, waste, etc.

• As approved by Landscape Architect.

General Structural Fill

• General structural fill outside building footprint

• Parking area embankments/fills.

• Utility backfill outside the building footprint.

• Soil classified as GP, GM, GW, GC, SP, SM, or SW according to the USCS.

• Soil within 3 feet below the finished building subgrade may not contain particles larger than 3 inches in diameter.

• Soil must contain less than 3 percent (by weight) of organics, vegetation, wood, metal, plastic, or other deleterious substances.

Granular Structural Fill

• Any embankment/fill.

• Structural fill within the building footprint plus 10 feet laterally.

• Soil improvements.

• Over-excavations.

• General structural fill uses.

• Soil meeting requirements stated in MPWSS 2010 Section 02234 or 02235 – Sub Base Course or Crushed Base Course.

• Soils meeting general structural fill requirements.

Crushed Base Course1

(Slab aggregate)

• Granular structural fill.

• General structural fill.

• Slab support aggregate.

• Soil must meet general structural fill requirements.

• Soil meeting requirements stated in MPWSS 2010 Section

02235 – Crushed Base Course.

Unsatisfactory Soil

NONE

• Soil classified as MH, CH, OH, OL, or PT may not be used at the project site.

• Soil not meeting the material specifications for granular structural fill may not be used within the building area as defined the Structural Fill section.

• Any soil type not maintaining moisture contents within 3 percent of optimum during compaction is unsatisfactory soil.2

• Any soil containing more than 5 percent (by weight) of organics, vegetation, wood, metal, plastic or other deleterious substances.

1. Crushed base course includes both “top course” and “base course” crushed aggregate according to MPWSS Standards.

2. Unsatisfactory soil that is wetted or dried to within 3 percent of optimum moisture may be used as structural fill, providing all other criteria are met for appropriate structural fill use per Table 1 above.

We recommend slab subgrades be scarified to a depth of 8 inches, moisture conditioned and recompacted to 92 percent of the maximum dry density of the soil referencing ASTM D1557

(modified Proctor). Structural fill shall be compacted to at least 95 percent of the maximum dry density of the soil according to ASTM D1557. Fill placed outside any building or pavement envelope can be placed as non-structural fill (i.e. landscape fill) with the understanding that there are no structures (sidewalk, curbs, signs, etc.) planned directly above the landscape fill. We recommend landscape fill be compacted to a minimum of 85 percent of the maximum dry density of the soil based on ASTM D1557.

Any structural fill product should be moisture-conditioned to near optimum moisture content and placed in maximum 12-inch-thick, loose lifts. The lift thickness above assumes large compaction equipment such as vibratory rollers with drum energy of 5 to 10 tons or greater is used to attempt compaction. If smaller or lighter compaction equipment is provided, reduce the lift thickness to meet the compaction requirements presented herein.

Imported structural fill products may be too coarse for Proctor testing if they contain more than 30 percent particles retained on the No. ¾ sieve (i.e. oversize material). We recommend oversized material be compacted using a “method specification”. Method compaction should occur by applying at least 5 complete passes over the soil using vibratory compaction equipment with a drum energy rating of at least 10 tons. We do not recommend smaller compaction equipment for method compaction. Method compaction should be observed on a full-time basis by STRATA and should achieve a firm, unyielding and interlocking structural fill surface. All structural fill products should be moisture-conditioned to near optimum moisture content and be placed in maximum 12-inch-thick loose lifts. If the structural fill can be tested using Proctor methods, smaller or lighter equipment may require a reduction in fill lift thickness.

Wet Weather/Wet Soil Construction

Once subgrade elevation is achieved, it is the contractor’s responsibility to protect the soil from degrading under construction traffic, freezing and/or wet weather. Initial footing/slab-on-grade excavations should not be completed within 24 hours of expected precipitation. Footing or slab concrete placement should never be attempted following a significant precipitation event and the subgrade should never be allowed to freeze prior to concrete or fill placement. The condition of the subgrade and careful construction procedures are critical to foundation and slab stability and the long-term performance of the structure.

We strongly recommend earthwork construction take place during dry weather conditions.

Portions of the on-site soil will be susceptible to pumping or rutting from heavy loads such as rubber-tired equipment or vehicles any time of the year. If construction commences before soil can dry after precipitation or during wet periods of the year (October through June), earthwork at the subgrade elevation should be completed by low pressure, track-mounted equipment that spreads and reduces vehicle loads. Work should not be performed immediately after rainfall or until soil can dry to below optimum moisture content. Time for proper moisture conditioning during dry weather is critical to reducing excessive over-excavations and the need to import granular structural fill.

Over-excavations and Soil Improvement Construction

Based on our observations during our subsurface evaluations, we anticipate that competent native alluvial silt will be encountered at the base of the footing excavations. Should areas of unsuitable or unstable soils be encountered, they must be over excavated until competent undisturbed native silt is encountered. The resulting over excavations shall be backfilled with structural fill in accordance with the Structural Fill and Required Compaction section.

Foundation Design

We recommend proposed shallow conventional, wall and column foundations for the proposed structure bear on granular soil improvements constructed on native silt. Based on preparing the foundation bearing soil units as described herein, the following items provide our recommended shallow foundation design parameters:

Maximum allowable bearing pressure: 1,500 psf

• Requires footings to bear on native silt alluvium exhibiting pocket penetrometer readings greater than 2.0 tons-per-square-foot (tsf).

• Maximum 33 percent increase allowed for short term load increases such as wind or seismic.

Estimated foundation vertical settlement:

• Total settlement: 1.0 inches.

• Differential settlement: 0.5 inches in 30-foot horizontal span.

Lateral load resistance:

• Foundation base friction coefficient:

0.3 for foundations cast directly on granular structural fill.

Footing embedment:

• Exterior footings must extend at least 36 inches below the final, exterior ground surface to help protect against frost action. Local building codes may require deeper embedment.

• Interior footings must extend at least 24 inches beneath the finished floor elevation.

Interior foundations must maintain at least 4 inches of crushed base course cover between top of the footing and the bottom of the concrete slab. Due to their propensity for reflective cracking, avoid thickened slabs.

Seismicity

We expect the 2012 IBC will be utilized for project structural design. Section 1613 in the

2012 IBC outlines procedures for evaluating site ground motions and design spectral response accelerations. Based on our knowledge of the upper 100 feet of the soil profile, we recommend

Seismic Site Class D be utilized as a basis for structural seismic design.

Liquefaction Potential

Local well drilling data recorded by the Montana Bureau of Mines and Geology indicates the areas near the project site are underlain by silt or clay deposits that are in turn underlain by gravels at depths of approximately 100 feet below existing grades. Based on the well data, and predominantly fine-grained nature of the alluvial soils encountered in the project vicinity coupled with the relatively low risk for high-intensity ground shaking due to seismic events, the potential for liquefaction induced settlement at the site is considered very low.

Concrete Slab-on-Grade Floors

General

Concrete slab-on-grade floors shall be supported by a minimum of 8 inches of crushed base course meeting the requirements shown in Table 1 and compacted to at least 95 percent of ASTM

D1557. Prepare slab-on-grade subgrades per the recommendations in the Earthwork and Site

Preparation report section. However, K-Con’s structural design team is responsible for structural slab support section design based on the anticipated use and loading.

Moisture Protection

Interior floor slabs may be susceptible to moisture migration caused by subsurface capillary action and vapor pressure. Moisture migration through floor slabs can break down a floor covering, its adhesive, or cause various other floor covering performance problems. Specifically, STRATA has participated in numerous projects where inadequate vapor protection caused significant damage to moisture-susceptible flooring systems. Often, these moisture problems were associated with either no moisture protection below the slab or, alternatively, un- or inadequately sealed sub slab penetrations that allowed vapor migration and damage the flooring system. Plumbing penetrations are notoriously problematic for under slab vapor protection.

Vapor retarders must consist of thick, puncture-proof polyethylene sheeting placed immediately below the floor slab. An example of this material is Stego Wrap™, a 15-mil retarder.

Alternatively, the vapor barrier may be covered with an additional 2-inch-thick layer of clean, coarse sand placed between the aggregate base course and the concrete slab-on-grade floors, if the base material and slabs are placed with a waterproofing system in-place. Vapor barrier installation options are outlined in Figure 1 below.

Figure 1: Vapor Retarder Flowchart (Adapted from Figure 3-1 of ACI 302.1R-04)

Form stakes, piping, or other sub-slab penetrations must never penetrate the vapor retarder.

Carefully design and construct any vapor retarder penetrations to reduce vapor transport through such penetrations. Even if these recommendations are used, water vapor migration through the concrete floor slab is still possible. Floor covering should be selected accordingly. Manufacturer's recommendations should be strictly followed. Where vapor retarders are utilized, the flooring and concrete slab contractors, as well as the plastic sheeting manufacturer, should be consulted regarding additional slab cure time requirements and/or the potential for slab curling.

We recommend you strongly consider the risks of excluding a vapor barrier prior to omitting such a system. Where floor coverings or equipment must be protected from damage by moist floor conditions, we strongly suggest a vapor retarder be installed.

Ultimately, the location of the vapor retarder (if specified) should be carefully considered by you and your Architect. ASTM E1643 and American Concrete Institute (ACI) Committee 302 are 2 publications that provide considerations for vapor retarder locations. Studies have shown that decreased water cement ratios, higher strength concrete and good construction finishing practices significantly decrease any negative impacts associated with the above options for vapor retarder locations.

Site Drainage

Perimeter Foundation Drainage Considerations

Foundations must be constructed with adequate drainage systems to reduce the potential for instability, leakage, or seepage. Maintaining drained conditions beneath foundations is critical to their performance. Typical methods for foundation drainage include the placement of 4-inch diameter perforated PVC pipe at or near the base of the footing excavations, depending on foundation construction. Install foundation drains with a minimum 0.5 percent slope and dispose of collected water in stormwater collection system designed by civil engineer. Foundation drains must not be connected to roof drains, or other nearby drainage facilities. Where gravity drainage cannot be accomplished, design and install pumps for water removal. At this time and unless the building concepts create below grade spaces, or if excavation more than a few feet below existing surfaces is contemplated, our opinion is pumping to facilitate foundation drainage will not be required.

Site Grading and Surface Drainage

Runoff from precipitation, snowmelt, seeps or springs must be reduced and routed away from structures and not be allowed to infiltrate, or be diverted towards foundations, pavements, exterior flatwork, and slab subgrades. Runoff or water migrating along the ground surface must be intercepted, collected, and conveyed away from structures by appropriately designed surface water management features. Surface water management is especially critical to help reduce moisture content changes that could create frost action and cause interior or exterior flatwork distress.

We recommend the ground surface outside the proposed structure be sloped at least 5 percent away for a minimum of 10 feet to rapidly convey surface water or roof runoff away from foundations. Establish design grades greater than 10 feet from structures at least 2 percent away and toward acceptable areas, as determined via our recommendations and site grading design.

Exterior slabs are susceptible to frost action, which can generate substantial frost heave during winter months. The potential for frost heave may not be acceptable at entries or other critical areas adjacent to the building that will be exposed to weather. We recommend over-excavating frost susceptible soil beneath exterior slabs and replacing it with non-frost susceptible material, such as crushed base course, to reduce but not eliminate flatwork deflection.

ADDITIONAL RECOMMENDED SERVICES

Geotechnical Design Continuity

The information contained in this report is based on preliminary development plans and earthwork specifications relayed to us by K-Con and our understanding of planned construction.

Final building configuration and loading conditions, as well as site geometry, can significantly alter our opinions and design recommendations. Specifically, structural design-load changes, grading plans, and site drainage facility locations may require additional geotechnical involvement or analyses specific to the actual anticipated construction. If the assumptions stated herein or our project understanding is incorrect, or if conditions change, our recommendations may not be appropriate. Therefore, it is critical STRATA provide geotechnical continuity through final project planning and design as individual aspects become available during design development project phases. If we are not provided such opportunities, we cannot be responsible for soil-related design or construction-related errors, omissions, delays or increased costs that are identified during construction.

Plan and Specification Review

We recommend STRATA review the final earthwork, grading, foundation, slab, hardscapes, and other relevant plans and specifications for the proposed project. It has been our experience that having consultants from the design team review the construction documents prior to construction helps reduce the potential for errors, and also reduces costly changes to the contract during construction.

Construction Observation and Testing

STRATA is currently retained to provide construction monitoring to document site soil conditions and observe that our report recommendations are incorporated into the grading plan for construction. Such observation is a critical part of the geotechnical design process and can help reduce the potential for soil engineering or construction-related errors or omissions. Further, material testing and special inspection services are required by local building departments, the IBC, and project specifications. STRATA is available to provide these services and to document the soil-engineering requirements herein exist at the time of foundation, slab, and hardscape placement.

EVALUATION LIMITATIONS

This report is prepared to assist K-Con and the design team with project planning, design and construction for the planned replacement shop building in the National Bison Range Wildlife

Refuge near Moiese, Montana. Our geotechnical findings and opinions have been developed based on the authorized subsurface exploration and laboratory testing, as well as our stated project understanding. STRATA’s services are limited to providing geotechnical engineering recommendations and opinions, as outlined in our proposal. STRATA did not provide infiltration testing to assess site stormwater percolation rates nor did we perform a detailed analysis of liquefaction potential. Based on the fine grained nature of the onsite soils and the depth to groundwater, we anticipate the risk for liquefaction as very low.

Our services consist of professional opinions and findings made in accordance with generally accepted geotechnical engineering principles and practices in western Montana at the time of this report. The geotechnical recommendations provided in this report are based on the premise that

STRATA will provide appropriate geotechnical consultation and testing during building pad preparation, to confirm subsurface conditions during construction. If STRATA is not contacted to provide the recommended geotechnical-related observations, we are not responsible for contractor or designer errors, omissions, report misinterpretations or the performance of improvements we did not observe during construction. This acknowledgment is in lieu of any express or implied warranties. Further, STRATA cannot be liable for observation, testing, or design verification accomplished by others. Reliance on this document by others is governed by specific terms and conditions, which must be accepted by those seeking to rely on the information herein.

The following plates and appendices accompany this report. Report text and the following visual aids cannot be separated or individually relied upon outside the context of the entire document.

Plate 1: Exploration Site Map Appendix A: Unified Soil Classification System (USCS) Exploration Logs Appendix B: Laboratory Test Results

Reference: Base image and Vicinity Map provided by Google Maps. No Scale Intended

EXPLORATION SITE MAP

Proposed Replacement Shop Building National Bison Range Wildlife Refuge

Moiese, Montana

PLATE 1MI14094A

THIS PLAN COMPRISES A PORTION OF STRATA’S GEOTECHNICAL REPORT AND THE TEXT OF THE REPORT CONTAINS ESSENTIAL INFORMATION. BEFORE UTILIZING THIS PLAN FOR ANY PURPOSE WHATSOEVER, THE REPORT SHOULD BE READ COMPLETELY. THIS PLAN IS INTENDED TO INDICATE APPROXIMATE LOCATIONS OF GEOTECHNICAL EXPLORATIONS, TESTS AND OTHER GEOTECHNICAL ISSUES (REFER TO TEXT FOR INFORMATION ON METHODS, RESULTS AND SUBSEQUENT RECOMMENDATIONS). THESE LOCATIONS AND INFORMATION WERE ADDED TO EXISTING PLANS OF THE SITE PREVIOUSLY PREPARED BY OTHERS AND NO CHECK OF ACCURACY, APPROPRIATENESS, ETC., OF INFORMATION PROVIDED BY OTHERS WAS PERFORMED SINCE SUCH CHECKS WERE NOT PART OF

STRATA’S SCOPE OF WORK.

LEGEND

Approximate Test Pit location observed by STRATA on October 3, 2014.

TP-1

(10.0’)

Approximate Test Pit depth observed by STRATA on October 3, 2014

TP-3

(8.5’)

TP-4

(8.0’)

TP-2

(9.5’)

TP-1

(10.0’)

Site Location

VICINITY MAP

NOT TO SCALE

Site Location

Proposed Replacement Shop Building

APPENDIX A

UNIFIED SOIL CLASSIFICATION SYSTEM (USCS)

EXPLORATION LOGS

1.5

2.0

> 4.0

17.7

16.0

12.9

ML

Observed moderate vegetation to 3.0" BGS.

ATTERBERG LIMITS

NP

Backhoe observed increase in digging difficulty at 3.0' BGS.

ALLUVIUM - SILT, (ML) tan to brown, firm to stiff, moist

Test Pit Terminated at 10.0 Feet.

LL PI

A tte rb er g Li m its

P oc ke t P en

(t sf

M oi st ur e C on te nt

D ry

D en si ty

(p cf

P as si ng N o.

S ie ve

U .S

.C .S

C la ss

S ym bo l

S am pl e

T yp e

Remarks

Note: BGS = Below Ground Surface

D ep th (f t)USCS Description

Sheet 1 Of 1Logged By: RML

Bucket Width: 30 Inches

Date Excavated: 10-03-2014

Test Pit Number: TP-1

Depth to Groundwater: N.E.

EXPLORATORY

TEST PIT LOG

Backhoe: DEERE 310SG

Client: K-Con, Inc.

Project: MI14094A

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0.0

2.5

5.0

7.5

10.0

3.0

2.5

> 4.0

10.397.0

ML

Observed moderate vegetation to 3.0" BGS.

ASTM D1557

117.5 pcf @ 13.5%

Backhoe observed increase in digging difficulty at 3.0' BGS.

ALLUVIUM - SILT, (ML) tan to brown, firm to stiff, moist

Test Pit Terminated at 9.5 Feet.

LL PI

A tte rb er g Li m its

P oc ke t P en

(t sf

M oi st ur e C on te nt

D ry

D en si ty

(p cf

P as si ng N o.

S ie ve

U .S

.C .S

C la ss

S ym bo l

S am pl e

T yp e

Remarks

Note: BGS = Below Ground Surface

D ep th (f t)USCS Description

Sheet 1 Of 1Logged By: RML

Bucket Width: 30 Inches

Date Excavated: 10-03-2014

Test Pit Number: TP-2

Depth to Groundwater: N.E.

EXPLORATORY

TEST PIT LOG

Backhoe: DEERE 310SG

Client: K-Con, Inc.

Project: MI14094A

S T

R A

T A

T E

S T

P

IT

S

T R

A T

A .G

D T

1/

/1

9:

P

A U

LI

-P

C \U

S E

R S

\P U

B

LI

C \D

O C

U M

E N

T S

\M A

IN

\C

LI

E

N T

S \K

\K -C

O N

, I N

C \M

I1

A

K C

O N

B

IS

O N

R A

N G

E R

E P

LA

C

E M

E N

T S

H O

P

G E

E \A

U T

O C

A D

\M I1

A T

E S

T P

IT

L

O G

S

.G

P J

0.0

2.5

5.0

> 4.0

> 4.0

> 4.0

13.0

10.8

ML

Observed moderate vegetation to 3.0" BGS.

Backhoe observed increase in digging difficulty at 3.0' BGS.

ALLUVIUM - SILT, (ML) tan to brown, firm to stiff, moist

Test Pit Terminated at 8.5 Feet.

LL PI

A tte rb er g Li m its

P oc ke t P en

(t sf

M oi st ur e C on te nt

D ry

D en si ty

(p cf

P as si ng N o.

S ie ve

U .S

.C .S

C la ss

S ym bo l

S am pl e

T yp e

Remarks

Note: BGS = Below Ground Surface

D ep th (f t)USCS Description

Sheet 1 Of 1Logged By: RML

Bucket Width: 30 Inches

Date Excavated: 10-03-2014

Test Pit Number: TP-3

Depth to Groundwater: N.E.

EXPLORATORY

TEST PIT LOG

Backhoe: DEERE 310SG

Client: K-Con, Inc.

Project: MI14094A

S T

R A

T A

T E

S T

P

IT

S

T R

A T

A .G

D T

1/

/1

9:

P

A U

LI

-P

C \U

S E

R S

\P U

B

LI

C \D

O C

U M

E N

T S

\M A

IN

\C

LI

E

N T

S \K

\K -C

O N

, I N

C \M

I1

A

K C

O N

B

IS

O N

R A

N G

E R

E P

LA

C

E M

E N

T S

H O

P

G E

E \A

U T

O C

A D

\M I1

A T

E S

T P

IT

L

O G

S

.G

P J

0.0

2.5

12.5

13.6

12.0

92.5

ML

Observed moderate vegetation to 3.0" BGS.

ATTERBERG LIMITS

NP

Backhoe observed increase in digging difficulty at 3.0' BGS.

ALLUVIUM - SILT, (ML) tan to brown, firm to stiff, moist

Test Pit Terminated at 8.0 Feet.

LL PI

A tte rb er g Li m its

P oc ke t P en

(t sf

M oi st ur e C on te nt

D ry

D en si ty

(p cf

P as si ng N o.

S ie ve

U .S

.C .S

C la ss

S ym bo l

S am pl e

T yp e

Remarks

Note: BGS = Below Ground Surface

D ep th (f t)USCS Description

Sheet 1 Of 1Logged By: RML

Bucket Width: 30 Inches

Date Excavated: 10-03-2014

Test Pit Number: TP-4

Depth to Groundwater: N.E.

EXPLORATORY

TEST PIT LOG

Backhoe: DEERE 310SG

Client: K-Con, Inc.

Project: MI14094A

S T

R A

T A

T E

S T

P

IT

S

T R

A T

A .G

D T

1/

/1

9:

P

A U

LI

-P

C \U

S E

R S

\P U

B

LI

C \D

O C

U M

E N

T S

\M A

IN

\C

LI

E

N T

S \K

\K -C

O N

, I N

C \M

I1

A

K C

O N

B

IS

O N

R A

N G

E R

E P

LA

C

E M

E N

T S

H O

P

G E

E \A

U T

O C

A D

\M I1

A T

E S

T P

IT

L

O G

S

.G

P J

0.0

2.5

APPENDIX B

LABORATORY TEST RESULTS

Project: Bison Range Replacement Shop Client: K-Con, Inc.

File Name: MI14094A Date Sampled: 10/22/2014 Sample Number: MI1400386D Sample Idetification: TP-2, 1.0'-1.5' BGS Sample Classification: SILT (ML)

ASTM D1557

Maximum Dry Density, pcf : 117.5 Optimum Moisture Content, %: 13.5

3/4 inch 3/8 inch

#4 screen

98 100

8 10 12 14 16 188.5 9.0 9.5 10.5 11.0 11.5 12.5 13.0 13.5 14.5 15.0 15.5 16.5 17.0 17.5

MOISTURE %

D R

Y D

E N

S

IT

Y pc f)

Zero Air Voids Curve spg. 2.63

117.5

GRADING ANALYSIS

Method A

Reviewed By James R. Thomasson, P.E.