Attachment_21_-_RSC_Geotech_Report_(2016).pdf

Attachment 21 Geotechnical Report

Geotechnical Engineering Report Range Operations and Maintenance Facilities

Solicitation No. TH0316

USACE, W912ER-14-D-0003

Melrose Air Force Range Roosevelt County, New Mexico

June 16, 2016 Terracon Project No. 66165043

Prepared for:

CH2M Hill, Inc.

Englewood, Colorado

Prepared by:

Terracon Consultants, Inc.

Albuquerque, New Mexico

Terracon Consultants, Inc. 4905 Hawkins NE Albuquerque, New Mexico 87109 P [505] 797 4287 F [505] 797 4288 terracon.com

June 16, 2016

CH2M Hill, Inc.

9191 South Jamaica Street Englewood, Colorado 80112

Attn: Ms. Tracey Spielmann Senior Project Manager P: (720) 286-1452 E: Tracey.Spielmann@ch2m.com

Re: Geotechnical Engineering Report Range Operations and Maintenance Facilities Solicitation No. TH0316

USACE, W912ER-14-D-0003

Melrose Air Force Range Roosevelt County, New Mexico Terracon Project No. 66165043

Dear Ms. Spielmann:

Terracon Consultants, Inc. (Terracon) has completed the geotechnical engineering services for the above referenced project. These services were performed in general accordance with our proposal number P66165043 dated April 1, 2016 and the CH2M Hill, Inc Award/Contract No 10006-7-104912 dated April 25, 2016. This geotechnical engineering report presents the results of the subsurface exploration and provides geotechnical recommendations concerning earthwork and the design and construction of foundations, floor slabs, and roadway/parking lot surfacing for the proposed project.

We appreciate the opportunity to be of service to you on this project. If you have any questions concerning this report, or if we may be of further service, please contact us.

Sincerely, Terracon Consultants, Inc.

Meagan J. Duneman, P.E. Michael E. Anderson, P.E.

Project Engineer Principal

Copies to: Addressee (3 via mail, 1 via email)

Range Operations and Maintenance Facilities ■ Roosevelt County, New Mexico June 16, 2016 ■ Terracon Project No. 66165043

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TABLE OF CONTENTS

Page EXECUTIVE SUMMARY ............................................................................................................. i

1.0 INTRODUCTION

2.0 PROJECT INFORMATION

2.1 Project Description

2.2 Site Location and Description

3.0 SUBSURFACE CONDITIONS

3.1 Regional Geologic and Hydrologic Conditions

3.2 Geologic and Seismic Hazards

3.3 Typical Subsurface Profile

3.4 Groundwater

3.5 Percolation Test Results

4.0 RECOMMENDATIONS FOR DESIGN AND CONSTRUCTION

4.1 Geotechnical Considerations

4.2 Earthwork

4.2.1 Site Preparation

4.2.2 Excavation

4.2.3 Subgrade Preparation

4.2.4 Fill Materials and Placement

4.2.5 Compaction Requirements

4.2.6 Shrinkage

4.2.7 Slopes

4.2.8 Grading and Drainage

4.2.9 Corrosion Potential

4.3 Foundation Recommendations

4.3.1 Design Recommendations

4.3.2 Construction Considerations

4.4 Seismic Considerations

4.5 Floor Slab

4.5.1 Design Recommendations

4.5.2 Construction Considerations

4.6 Lateral Earth Pressures

4.6.1 Design Recommendations

4.7 Gravel Surfacing

4.7.1 Portland Cement Concrete Floor Slab Design Recommendations

4.7.2 Gravel Surfacing Design Recommendations

4.7.3 Materials Specifications

4.7.4 Gravel Surfaced Road Maintenance

5.0 GENERAL COMMENTS

TABLE OF CONTENTS– continued Exhibit No.

Appendix A – Field Exploration Field Exploration Description ............................................................................... A1 Site Location Map ................................................................................ A2a thru A2c Boring Location Plan ........................................................................................... A3 Boring Logs ........................................................................................... A4 thru A15 Percolation Test Results ...................................................................... A16 thru A18 Explanation of Boring Log Information ............................................................... A19 Unified Soil Classification System ...................................................................... A20

Appendix B – Laboratory Testing Laboratory Test Description ................................................................................. B1 Grain Size Distribution ............................................................................. B2 thru B5 Consolidation Test Results .................................................................... B6 thru B11 Moisture Density Relationship Test Results ......................................... B12 thru B14 California Bearing Ratio Test Results .................................................. B15 thru B17 Summary of Laboratory Results .......................................................... B18 and B19 Chemical Test Results

Appendix C – Pavement Design Nomagraphs Pavement Design Nomagraphs .............................................................. C1 thru C2

EXECUTIVE SUMMARY

This geotechnical executive summary should be used in conjunction with the entire report for design and/or construction purposes. It should be recognized that specific details were not included or fully developed in this section, and the report must be read in its entirety for a comprehensive understanding of the items contained herein. The section titled General Comments should be read for an understanding of the report limitations.

A geotechnical exploration has been performed for the proposed Range Operations and Maintenance Facilities project to be located on Melrose Air Force Range in Roosevelt County, New Mexico. Terracon’s geotechnical scope of work included the advancement of 12 test borings to approximate depths of 3 to 31-½ feet below existing site grades.

Based on the information obtained from our subsurface exploration, the site is suitable for development of the proposed project. The following geotechnical considerations were identified:

Site Soils: The site soils generally consisted of sand with varying amounts of clay, silt and gravel, and lean clay with varying amounts of silt, sand and gravel. Groundwater was not encountered at the time of drilling. On-site sand soils are suitable for use as engineered fill. On-site clay soils (if encountered) are not suitable for use as engineered fill.

Foundations: The proposed buildings can be supported by shallow spread/continuous footings bearing on a zone of engineered fill.

Floor Slabs: The on-site surface and near surface soils are expected to exhibit low collapse and non- to low expansion potential when compacted and subjected to light loading conditions such as those imposed by floor slabs. Construction of floor slabs directly on engineered fills composed of on-site soils, or approved imported soils are considered acceptable for the project, provided that some movement can be tolerated. A minimum slab thickness of 6 inches is recommended for slabs subjected to truck traffic.

Gravel Surfacing: Light Duty parking areas – 4” aggregate base course (ABC); Heavy Duty truck drives and drive lanes – 6” ABC.

Percolation Rates: The shallow subsurface soils exhibited percolation rates ranging from about 10 to 120 minutes per inch (mpi).

Earthwork on the project should be observed and evaluated by Terracon. The evaluation of earthwork should include observation and testing of engineered fill, subgrade preparation, foundation bearing soils, and other geotechnical conditions exposed during construction.

GEOTECHNICAL ENGINEERING REPORT

RANGE OPERATIONS AND MAINTENANCE FACILITY

SOLICITATION NO. TH0316

USACE, W912ER-14-D-0003

MELROSE AIR FORCE RANGE

ROOSEVELT COUNTY, NEW MEXICO

Terracon Project No. 66165043

June 16, 2016

1.0 INTRODUCTION

This report presents the results of our geotechnical engineering services performed for the proposed Range Operations and Maintenance Facilities project to be located on Melrose Air Force Range in Roosevelt County, New Mexico. The report addresses the following:

subsurface soil conditions groundwater conditions earthwork foundation design and construction seismic considerations floor slab design and construction lateral earth pressures percolation rates gravel surfacing design and construction

Our geotechnical engineering scope of work for this project included the advancement of 12 test borings to depths ranging from approximately 3 to 31-½ feet below existing site grades.

Logs of the borings along with a Site Location Map and Boring Location Plan are included in Appendix A of this report. The results of the laboratory testing performed on soil samples obtained from the site during the field exploration are included in Appendix B of this report. Descriptions of the field exploration and laboratory testing are included in their respective appendices.

2.0 PROJECT INFORMATION

2.1 Project Description

ITEM DESCRIPTION

Site layout Refer to the Site Location Map and Boring Location Plan (Exhibits A1 and A2 in Appendix A)

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Structures

The project will include the construction of three (3) new buildings.

The size of the buildings is unknown at this time.

Site development will include the construction of gravel surfaced parking areas and drives, exterior flatwork, a septic tank and leach field, and the installation of utilities.

Building construction Pre-engineered metal buildings Proposed foundation Continuous and spread footings Finished floor elevation At or near existing site grade

Maximum loads Columns: 25 to 35 kips Wall: 0.5 to 1 kips per lineal foot max (assumed) Slabs: 150 to 250 psf max (assumed)

Grading in building area At or near existing site grade Grading in parking area At or near existing site grade Basement level Not Applicable

Pavement design criteria

United Facilities Criteria (UFC), “Aggregate Surfaced Roads and Airfield Areas” UFC 3-250-09FA dated January 2004.

United Facilities Criteria (UFC), “Pavement Design for Roads, Streets, Walks, and Open Storage Areas” UFC 3-250-01FA dated January 2004.

Traffic loading Driveways: Street Classification G - Traffic Category IV Parking Areas: Street Classification G - Traffic Category I Building slab: HS20 loading up to 10 per day

Off-site Improvements None

2.2 Site Location and Description

Location Near the northwest corner of Melrose Air Force Range in Roosevelt County, New Mexico.

Existing site features (site interior) Undeveloped land located near an existing runway.

Surrounding developments

North: Undeveloped land East: Existing unpaved runway West: Undeveloped land South: Existing unpaved runway

Current ground cover Soil and vegetation

Existing topography Relatively level to gently sloping site down to the north.

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3.0 SUBSURFACE CONDITIONS

3.1 Regional Geologic and Hydrologic Conditions

The project site is located within the High Plains section of the Great Plains physiographic province, also known as the Llano Estacado. Structurally, the Llano Estacado is a large mesa that while generally flat slopes gently to the east/southeast.

Forming the top of the mesa, the Blackwater Draw Formation generally overlies the Ogallala Formation and consists of eolian sands and lacustrine silts and clays deposited during the Pleistocene. A hard caliche layer called the Cap Rock generally forms the rim of the Llano Estacado and comprises parts of the Blackwater Draw and Ogallala Formations. The Ogallala Formation generally consists of alluvial and piedmont deposits formed from the erosion of the Rocky Mountains during the middle Miocene and early Pliocene. Deep below the Ogallala Formation are the red-brown siltstone, sandstone, and shale of the Chinle Formation.

The Ogallala Formation is the primary aquifer for the Llano Estacado. The water table is generally 200 to 400 feet BGS in the area. Due to the low amount of precipitation in the area and the high amount of pumping for irrigation, very little or no groundwater recharge occurs. Most of the water in the aquifer was likely placed during the last ice age.

3.2 Geologic and Seismic Hazards

Based upon our on-site reconnaissance, review of geologic maps and reports, subsurface soil conditions, and depth to groundwater, the impacts to the site from geologic hazards consisting of liquefaction, faulting, slope instability/landslides, flooding are considered very low.

Review of geologic information from the Quaternary fault and fold database1 indicates that the closest Quaternary faults are approximately 135 miles northwest and 160 miles southwest of the project site. Therefore the potential impacts from potential seismic events are considered low.

Collapsible and expansive soils have been located in the area of the project site and can be mitigated with proper engineering design and construction.

3.3 Typical Subsurface Profile

Specific conditions encountered at each boring location are indicated on the individual boring logs.

Stratification boundaries on the boring logs represent the approximate location of changes in soil

1 U.S. Geological Survey (USGS), 2010, “Quaternary Fault and Fold Database for the United States,” accessed July 20, 2015, from USGS web site: URL: http://earthquake.usgs.gov/regional/qfaults/

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Description Approximate Depth to Bottom of Stratum (feet)

Material Encountered Consistency/Density

Stratum 1 10 to 31-½ Sand. The silt, clay, and gravel content varied.

Very Loose to Very Dense

Stratum 2 15 to 20 Lean clay.* The silt, sand, and gravel content varied. Very Stiff to Hard

*Encountered in Boring Nos. B-01, B-02, and B-03 within the Joint Operations Planning Facility building footprint.

The sand soils were non-plastic to medium in plasticity. The clay soils were low in plasticity.

Laboratory tests were conducted on selected soil samples and the test results are presented in Appendix B. Laboratory test results indicate that the near surface soils exhibit low to moderate compression/consolidation potential at in-situ moisture contents. The near surface soils have a low to high tendency for compression/consolidation and a non- to low tendency for expansion when wetted and under increasing foundation loads. Some tests may reflect some sample disturbance due to the granular nature of the soils. Based upon our experience with similar soil conditions, we anticipate that the near surface soils have a low to moderate tendency for compression/consolidation and a non- to low tendency for expansion when wetted and under increasing foundation loads. When water is added to samples of laboratory compacted near-surface soils, we anticipate that the compacted soils will exhibit low compression/consolidation and non- to low expansive potential when subjected to light loading conditions such as those imposed by floor slabs.

Three (3) moisture density relations tests (ASTM D1557) were performed on representative samples of the shallow subsurface sand soils from depths of about 0 to 5 feet BGS. The results indicate that the subgrade materials encountered have maximum dry density values ranging from about 112 pounds per cubic foot (pcf) to 117 pcf and optimum moisture content values ranging from about 8 to 9 percent.

Three (3) California bearing ratio (CBR) tests were performed on representative samples of the shallow subgrade soils from depths of about 0 to 5 feet BGS. The results indicate that the subgrade materials encountered have CBR values ranging from about 32.7 to 47.4.

Laboratory test results indicate that on-site soils have non-detectable soluble sulfate and soluble chloride concentrations, pH values of 7.8 to 8.5, and minimum resistivity values of 3,140 to 6,180 ohm centimeters.

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3.4 Groundwater

Groundwater was not observed in the test borings at the time of field exploration, nor when checked upon completion of drilling. These observations represent groundwater conditions at the time of the field exploration and may not be indicative of other times, or at other locations.

Groundwater conditions can change with varying seasonal and weather conditions, and other factors.

Fluctuations in groundwater levels can best be determined by implementation of a groundwater monitoring plan. Such a plan would include installation of groundwater monitoring wells, and periodic measurement of groundwater levels over a sufficient period of time.

3.5 Percolation Test Results

Percolation tests were performed within Boring Nos. P-01, P-02, and P-03. Percolation tests were performed in general accordance with the EPA falling head percolation test procedure. The borings were filled with about 18 inches of water and allowed to pre-soak for a minimum of 24 hours. After this period, the borings were refilled with water to a depth of about 6 to 12 inches and water level readings were taken approximately every 10 to 60 minutes for a minimum period of about 4 hours or until a stable percolation rate was recorded.

Percolation testing conducted at the planned leach field location is summarized as follows:

Boring No. Percolation Test Depth (inches)

USCS

Classification

Approximate Percolation Rate (minutes/inch)

P-01 36 Silty Clayey Sand (SC-SM) 40

P-02 36 Clayey Sand (SC) 120

P-03 36 Silty Sand (SM) 10

It should be noted that the amount of clay, silt, and sand content, consistency/density of the subsurface soils, cementation, siltation, and vegetation growth along with other factors may affect the percolation rates. In addition, the actual percolation rate of each area may vary from the values reported in the borings.

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4.0 RECOMMENDATIONS FOR DESIGN AND CONSTRUCTION

4.1 Geotechnical Considerations

The site appears suitable for the proposed construction based upon geotechnical conditions encountered in the test borings. Potentially loose and compressible soils which show a low to moderate tendency for compression/consolidation and a non- to low tendency for expansion when elevated in moisture content will require particular attention in the design and construction.

Based on the geotechnical subsurface exploration, the laboratory test results, and our engineering analyses, the proposed buildings can be supported on a spread/continuous footing foundation system bearing on a zone of engineered fill. In addition, slab-on-grade floor systems supported on a zone of engineered fill can be used, provided some movement can be tolerated.

On-site sand soils are suitable for use as engineered fill. On-site clay soils (if encountered) are not suitable for use as engineered fill.

Geotechnical engineering recommendations for foundation systems and other earth connected phases of the project are outlined below. The recommendations contained in this report are based upon the results of field and laboratory testing (which are presented in Appendices A and B), engineering analyses, and our current understanding of the proposed project.

4.2 Earthwork

The following presents recommendations for site preparation, excavation, subgrade preparation and placement of engineered fills on the project. The recommendations presented for design and construction of earth supported elements including foundations, slabs and pavements (if applicable) are contingent upon following the recommendations outlined in this section.

Earthwork on the project should be observed and evaluated by Terracon. The evaluation of earthwork should include observation and testing of engineered fill, subgrade preparation, foundation bearing soils, and other geotechnical conditions exposed during the construction of the project.

4.2.1 Site Preparation

Strip and remove the existing vegetation, gravel surfacing, and other deleterious materials from the proposed structure and new gravel surfacing areas. Exposed surfaces should be free of mounds and depressions which could prevent uniform compaction.

The site should be initially graded to create a relatively level surface to receive fill, and to provide for a relatively uniform thickness of fill beneath the proposed building structure.

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Evidence of existing underground utilities were observed during the site reconnaissance.

Therefore, such features could be encountered during construction. If fills, loose, soft or unstable soils or underground facilities (to be abandoned) are encountered, such features should be removed and the excavation thoroughly cleaned prior to backfill placement and/or construction.

4.2.2 Excavation

It is anticipated that excavations for the proposed construction can be accomplished with conventional earthmoving equipment.

Based on the results from the soil borings, we do not anticipate groundwater control measures will be necessary in excavations up to about 31-½ feet below existing site grades. However, depending upon depth of excavation and seasonal conditions, groundwater may be encountered in excavations on the site. Pumping from sumps may be utilized to control water within excavations.

On-site soils may pump or become unstable or unworkable at high water contents. Workability may be improved by scarifying and drying. Overexcavation of wet zones and replacement with granular materials may be necessary. Lightweight excavation equipment may be required to reduce subgrade pumping.

Use of lime, fly ash, kiln dust, cement or geotextiles could also be considered as a stabilization technique. Laboratory evaluation is recommended to determine the effect of chemical stabilization on subgrade soils prior to construction.

4.2.3 Subgrade Preparation

Subgrade preparation and engineered fill placement should be performed in accordance with Sections 4.2.4 and 4.2.5. Engineered fill thickness should be performed in accordance with Sections 4.3 and 4.5.

Exposed areas which will receive fill, once properly cleared, should be scarified to a minimum depth of 10 inches, conditioned to near optimum moisture content, and compacted.

Areas of loose or unstable soils may be encountered at foundation bearing depth after excavation is completed for footings. When such conditions exist beneath planned footing areas, the subgrade soils should be surficially compacted prior to placement of the foundation system. If sufficient compaction cannot be achieved in-place, the soft soils should be removed and replaced as engineered fill. For placement of engineered fill below footings, the excavation should be widened laterally, at least eight (8) inches for each foot of fill placed below footing base elevations.

Subgrade soils beneath exterior slabs and beneath pavements (if applicable) should be scarified, moisture conditioned and compacted to a minimum depth of 10 inches. The moisture content and compaction of subgrade soils should be maintained until slab or pavement construction.

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4.2.4 Fill Materials and Placement

All fill materials should be inorganic soils free of vegetation, debris, and fragments larger than six inches in size. Pea gravel or other similar non-cementitious, poorly-graded materials should not be used as fill or backfill without the prior approval of the geotechnical engineer.

On-site sand soils and approved imported materials meeting the specification contained herein may be used as fill material for the following:

general site grading exterior slab areas foundation areas gravel surfacing areas interior floor slab areas foundation backfill

Imported soils for use as fill material within proposed building and gravel surfacing areas should conform to low volume change materials as indicated in the following specifications:

Percent Finer by Weight Gradation (ASTM C 136)

6" 3” .................................................................................................... 70-100 No. 4 Sieve ..................................................................................... 50-100 No. 200 Sieve .............................................................................. 35 (max)

Liquid Limit ....................................................................... 40 (max) Plasticity Index ................................................................. 20 (max) Maximum expansive potential (%)* ............................................ 1.0

*Measured on a sample compacted to approximately 95 percent of the ASTM D698 maximum dry density at about 3 percent below optimum water content. The sample is confined under a 100 psf surcharge and submerged/inundated.

On-site clay soils (if encountered) are not suitable for use as engineered fill.

Engineered fill should be placed and compacted in horizontal lifts, using equipment and procedures that will produce recommended moisture contents and densities throughout the lift.

Fill lifts should not exceed 10 inches loose thickness.

4.2.5 Compaction Requirements

Recommended compaction and moisture content criteria for engineered fill materials are as follows:

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Material Type and Location

Per the Standard Proctor Test (ASTM D 1557)

Minimum Compaction

Requirement (%)

Range of Moisture Contents for Compaction

Minimum Maximum

On-site sand or approved imported fill soils:

Beneath foundations: 95 -3% +3%

Beneath slabs: 95 -3% +3%

Beneath gravel surfacing: 95 -3% +3%

Fill embankments 95 -3% +3%

Aggregate base 95 -3% +3%

Miscellaneous backfill 90 -3% +3%

4.2.6 Shrinkage

For balancing grading plans, estimated shrink or swell of soils when used as compacted fill following recommendations in this report are as follows:

Estimated Shrink/Swell

Soil Type Based on ASTM D698 Clay -10% to -20% Sand -15% to -30%

4.2.7 Slopes

For permanent slopes in compacted fill and cut areas with a maximum height of 10 feet, recommended maximum configurations for on-site materials are as follows:

Maximum Slope Configuration

Soil Type Horizontal:Vertical (H:V) Clay 3H:1V Sand 2½H:1V

If steeper slopes are required for site development, we recommend the use of retaining walls/systems comprised of mechanically stabilized earth (MSE) retaining walls, soil nails, or cast-in-place (CIP) retaining walls.

The face of all slopes should be compacted to the minimum specification for fill embankments.

Alternately, fill slopes can be over-built and trimmed to compacted material.

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4.2.8 Grading and Drainage

All grades must provide effective drainage away from the buildings during and after construction.

Water permitted to pond next to the buildings can result in greater soil movements than those discussed in this report. These greater movements can result in unacceptable differential floor slab movements, cracked slabs and walls, and roof leaks. Estimated movements described in this report are based on effective drainage for the life of the structure and cannot be relied upon if effective drainage is not maintained.

Exposed ground should be sloped at a minimum 3 percent away from the building for at least five

(5) feet beyond the perimeter of the buildings. After building construction and landscaping, we recommend verifying final grades to document that effective drainage has been achieved. Grades around the structure should also be periodically inspected and adjusted as necessary, as part of the structure’s maintenance program.

Flatwork and pavements (if applicable) will be subject to post construction movement. Maximum grades practical should be used for paving and flatwork to prevent water from ponding.

Allowances in final grades should also consider post-construction movement of flatwork, particularly if such movement would be critical. Where paving or flatwork abuts the structure, effectively seal and maintain joints to prevent surface water infiltration.

4.2.9 Corrosion Potential

Laboratory test results indicate that on-site soils have non-detectable soluble sulfate and soluble chloride concentrations, pH values of 7.8 to 8.5, and minimum resistivity values of 3,140 and 6,180 ohm centimeters. These values should be used to determine potential corrosive characteristics of the on-site soils with respect to contact with the various underground materials which will be used for project construction.

Criteria published by the Cast Iron Pipe Research Institute indicates that the near surface subgrade soils generally have a moderate corrosive potential to cause corrosion to buried ferrous materials. Review of data published by the National Association of Corrosion Engineers indicates that the resistivity values concentrations places the soils in the moderately corrosive category. If there is concern regarding pipe corrosion, the use of PVC or poly-wrap should be considered.

Results of soluble sulfate testing indicate that ASTM Type I or I/II Portland cement is suitable for all concrete on and below grade. Foundation concrete should be designed for low sulfate exposure in accordance with the provisions of the ACI Design Manual, Section 318, Chapter 4.

Refer to Summary of Laboratory Results contained in Appendix B for the complete results of the various corrosivity testing conducted on the site soils in conjunction with this geotechnical exploration.

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4.3 Foundation Recommendations

The building structures can be supported by a shallow, spread and continuous footing foundation system bearing on engineered fill. Design recommendations for foundations for the proposed structures and related structural elements are presented in the following paragraphs.

4.3.1 Design Recommendations

DESCRIPTION VALUE

Foundation Type Conventional Shallow Spread Footings Structures Three (1)-story, at-grade building structures

Bearing Material Minimum of four (4) feet thickness of engineered fill below footings

Allowable Bearing Pressure 2,500 psf

Minimum Dimensions Columns: 24 inches Walls: 16 inches

Minimum Embedment Depth Below Finished Grade

Exterior - 18 inches Interior - 12 inches

Total Estimated Movement 1 inch Estimated Differential Settlement ½ inch in 40 feet under walls and columns

Finished grade is defined as the lowest adjacent grade within five (5) feet of the foundation for perimeter (or exterior) footings and finished floor level for interior footings. The allowable foundation bearing pressures apply to dead loads plus design live load conditions. The design bearing pressure may be increased by one-third when considering total loads that include wind or seismic conditions. The weight of the foundation concrete below grade may be neglected in dead load computations.

To resist uplift loads on the buildings, the foundations could be embedded deeper below existing site grades; the actual depth required should be determined by a structural engineer. The uplift forces should be resisted by the weight of the structure, its foundation and the soil placed over the foundation. Additional resistance to uplift forces can be provided by either increasing the size of the footings or their depth below final grade. In either case, the resistance is increased by the addition of the soil weight over the foundations. It is expected that the footings will be constructed such that the axial loads act at the centroid of the footing, producing a compressive soil reaction everywhere beneath the base of the foundation. Tension between the concrete and the soil should not be used in design. For uplift consideration, the total weight of the concrete mass (at 145 pcf) divided by an appropriate factor of safety could be used. The unit weight of soil above the footing can be taken as 115 pcf for design purposes when compacted as indicated in the Earthwork section of this report.

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Footings should be proportioned to reduce differential foundation movement due to differential loading conditions. Proportioning on the basis of equal total settlement is recommended;

however, proportioning to relative constant dead-load pressure will also reduce differential settlement between adjacent footings. Additional foundation movements could occur if water from any source infiltrates the foundation soils; therefore, proper drainage should be provided in the final design and during construction.

Footings, foundations, and masonry walls should be reinforced as necessary to reduce the potential for distress caused by differential foundation movement. The use of joints at openings or other discontinuities in masonry walls is recommended.

Foundation excavations and engineered fill placement should be observed by the geotechnical engineer. If the soil conditions encountered differ significantly from those presented in this report, supplemental recommendations will be required.

4.3.2 Construction Considerations

For proposed buildings, a minimum of four (4) feet of engineered fill is recommended below footings. The subgrade soils should be removed to a minimum depth of four (4) feet and a minimum of three (3) feet horizontally beyond the edge of footings. On-site soils are suitable for use as engineered fill.

If engineered fill is placed beneath the entire buildings, consideration could be given to extending the engineered fill zone a minimum horizontal distance of 5 feet beyond the outside edge of perimeter footings to support potential flatwork or other soil supported elements adjacent to the buildings.

Areas of loose or unstable soils may be encountered at foundation bearing depth after excavation is completed for footings. When such conditions exist beneath planned footing areas, the subgrade soils should be surficially compacted prior to placement of the foundation system. If sufficient compaction cannot be achieved in-place, the soft soils should be removed and replaced as engineered fill. The overexcavation and backfill procedure is described in the figure below.

Side walls should be sloped or braced for stability as required by

OSHA.

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4.4 Seismic Considerations

DESCRIPTION VALUE

2006 International Building Code Site Classification (IBC) 1 C2

Site Latitude N 34.32513°

Site Longitude W 103.83846°

SMs Spectral Acceleration for a Short Period 0.132g

SM1 Spectral Acceleration for a 1-Second Period 0.059g

SDs Spectral Acceleration for a Short Period 0.088g

SD1 Spectral Acceleration for a 1-Second Period 0.040g

Fa Site Coefficient for a Short Period 1.200

Fv Site Coefficient for a 1-Second Period 1.700 1 Note: In general accordance with the 2006 International Building Code, Table 1613.5.2. IBC Site Class is based on the average characteristics of the upper 100 feet of the subsurface profile.

2 Note: The 2006 International Building Code (IBC) requires a site soil profile determination extending to a depth of 100 feet for seismic site classification. The current scope does not include the required 100 foot soil profile determination. Borings extended to a maximum depth of 31-½ feet, and this seismic site class definition considers that dense or denser soil continues below the maximum depth of the subsurface exploration. Additional exploration to deeper depths would be required to confirm the conditions below the current depth of exploration.

4.5 Floor Slab

4.5.1 Design Recommendations

DESCRIPTION VALUE

Interior floor system Slab-on-grade concrete.

Floor slab support Minimum three (3) feet of engineered fill placed and compacted in accordance with Earthwork section of this report.

Subbase Compacted subgrade/engineered fill

Modulus of subgrade reaction 200 pounds per square inch per inch (psi/in) (The modulus was obtained based on our experience with similar subgrade conditions, and estimates obtained from ACI design charts.)

Construction of floor slabs directly on compacted fills composed of on-site soils or imported soils is considered acceptable for the project. Some movement of a slab-on-grade floor system is possible should the subgrade soils become elevated in moisture content due to the compression and expansion potential of the near surface soils. Additional slab movements could occur if water infiltrates the soils; therefore, proper drainage must be provided in the final design. To reduce potential slab movements, the subgrade soils should be prepared as outlined in the earthwork section of this report.

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If engineered fill is placed beneath the entire building, consideration could be given to extending the engineered fill zone a minimum horizontal distance of 5 feet beyond the outside edge of perimeter footings. Any fill used to raise the site to construction grade can be used to meet the engineered fill zone requirement.

In areas of exposed concrete, control joints should be saw cut into the slab after concrete placement in accordance with ACI Design Manual, Section 302.1R-37 8.3.12 (tooled control joints are not recommended). Additionally, dowels should be placed at the location of proposed construction joints. To control the width of cracking (should it occur) continuous slab reinforcement should be considered in exposed concrete slabs.

Positive separations and/or isolation joints should be provided between slabs and all foundations, columns or utility lines to allow independent movement. Interior trench backfill placed beneath slabs should be compacted in accordance with recommendations outlined in the Earthwork section of this report. Other design and construction considerations, as outlined in the ACI Design Manual, Section 302.1R are recommended.

4.5.2 Construction Considerations

Some total and differential movement of a slab-on-grade floor system is possible should the subgrade soils become elevated in moisture content. Such movements are anticipated to be within general tolerance for normal slab-on-grade construction. To reduce potential slab movements, the floor system should be supported on a zone of engineered fill a minimum three

(3) feet in thickness. The engineered fill and subgrade soils should be placed as outlined in the Earthwork section of this report. On-site soils are suitable for use as engineered fill.

4.6 Lateral Earth Pressures

4.6.1 Design Recommendations

For soils above any free water surface, recommended equivalent fluid pressures for unrestrained foundation elements when using on-site soils as backfill are:

ITEM SOIL TYPE VALUE

Active Case On-site clay soils

On-site or imported sand soils 45 psf/ft 35 psf/ft

Passive Case On-site clay soils

On-site or imported sand soils 325 psf/ft 400 psf/ft

At-Rest Case On-site clay soils

On-site or imported sand soils 65 psf/ft 55 psf/ft

Coefficient of Base Friction All soils 0.351

Responsive ■ Resourceful ■ Reliable 15

ITEM SOIL TYPE VALUE

1Note: The coefficient of base friction should be reduced to 0.30 when used in conjunction with passive pressure.

The lateral earth pressures herein do not include any factor of safety and are not applicable for submerged soils/hydrostatic loading. Additional recommendations may be necessary if such conditions are to be included in the design.

Fill against foundations (if applicable) should be compacted to densities specified in the Earthwork section of this report. Compaction of each lift adjacent to walls should be accomplished with hand-operated tampers or other lightweight compactors.

4.7 Gravel Surfacing and Portland Cement Concrete

The following recommendations should be considered for areas with vehicular traffic. The pavement design nomographs have been included in Appendix C.

4.7.1 Portland Cement Concrete Floor Slab Design Recommendations The design approach used to populate the table outlined below was based on the United Facilities Criteria (UFC), “Pavement Design for Roads, Streets, Walks, and Open Storage Areas” UFC 3- 250-01FA dated January 2004.

The design of pavement thickness was based on the following:

Traffic Category IVA for three-, four, and five-axle trucks (HS20) Street Classification of F (<70 vehicles per day) A Pavement Design Index of 4 A K value of 200 pounds per cubic inch A design life of 20 years

As a minimum, we recommend that the following typical pavement sections be considered.

MATERIAL

Thickness (in)

Parking Areas

Portland Cement Concrete 6

Aggregate Base Course or Gravel 4*

Prepared Subgrade 10

*Minimum per UFC 3-250-01FA

Responsive ■ Resourceful ■ Reliable 16

4.7.2 Gravel Surfacing Design Recommendations

Pavement sections based upon a more detailed pavement design could be provided if specific traffic loading, frequencies, and desired pavement design life are provided.

The design approach used to populate the table outlined below was based on the United Facilities Criteria (UFC), “Aggregate Surfaced Roads and Airfield Areas” UFC 3-250-09FA dated January 2004.

The design of pavement thickness was based on the following:

Traffic Category I for passenger cars, panel and pickup in parking areas Traffic Category IVA for three-, four, and five-axle trucks (HS20) Street Classification of G for driveways and G for parking areas (<70 vehicles per day) A Pavement Design Index of 2 for driveways and 1 for parking areas Laboratory tested CBR values ranging from 32.7 to 47.4 A minimum CBR characterization of 8 based on the compacted clayey sand subgrade soils encountered at the site

As a minimum, we recommend that the following typical pavement sections be considered.

MATERIAL

Thickness (in)

Access Roads Parking Areas

Aggregate Base Course or Gravel 6 4*

Prepared Subgrade 10 6

*Minimum per UFC 3-250-09FA

To maintain accessibility, proper drainage and future roadway maintenance will be required as previously discussed in this report. Maintenance recommendations are outlined in subsequent sections of this report.

4.7.3 Materials Specifications

The aggregate base course (if used) should consist of a blend of sand and gravel, which meets strict specifications for quality and gradation. Use of materials meeting Section 304 (Base Course) of 2014 NMDOT Specifications is required. Aggregate base course material should be tested to determine compliance with these specifications prior to importation to the site.

Aggregate base course should be compacted to a minimum 95% of maximum dry density and within 2 percent of optimum moisture content as determined by AASHTO T180/ASTM D1557.

Aggregate base course should be placed and compacted in accordance with Sections 303 and 304 of NMDOT Specifications.

Responsive ■ Resourceful ■ Reliable 17

Portland cement concrete should conform to Sections 450, 451, 509 and 510 of the NMDOT specifications. Future performance of pavements constructed at this site will depend upon several factors, including maintaining stable moisture content of the subgrade soils and providing for a planned program of preventative maintenance.

4.7.4 Gravel Surfaced Road Maintenance

Service life of the gravel surfacing is based on periodic maintenance, adequate drainage, and traffic consistent with the stated assumptions in this report. Preventive maintenance should be planned and provided for through an on-going management program. Preventive maintenance activities are intended to slow the rate of deterioration, and to preserve the gravel surfacing investment. Preventive maintenance consists of removal and replacement of unstable subgrade and re-establishing aggregate base course thickness. Preventive maintenance is usually the first priority when implementing a planned maintenance program and provides the highest return on investment for pavements. Prior to implementing any maintenance, additional engineering observation is recommended to determine the type and extent of preventive maintenance.

Long term gravel surfacing performance depends on several factors, including maintaining subgrade moisture levels and providing for preventive maintenance. The following recommendations should be considered the minimum:

Site grading at a minimum 2% grade away from the gravel surfacing.

The subgrade and the pavement surface have a minimum ¾ inch per foot slope to promote proper surface drainage.

Consider appropriate edge drainage and pavement under drain systems.

V-ditches or swales to direct surface water away from traffic areas

5.0 GENERAL COMMENTS

Terracon should be retained to review the final design plans and specifications so comments can be made regarding interpretation and implementation of our geotechnical recommendations in the design and specifications. Terracon also should be retained to provide observation and testing services during grading, excavation, foundation construction and other earth-related construction phases of the project.

The analysis and recommendations presented in this report are based upon the data obtained from the borings performed at the indicated locations and from other information discussed in this report. This report does not reflect variations that may occur between borings, across the site, or due to the modifying effects of construction or weather. The nature and extent of such variations may not become evident until during or after construction. If variations appear, we should be

Responsive ■ Resourceful ■ Reliable 18 immediately notified so that further evaluation and supplemental recommendations can be provided.

The scope of services for this project does not include either specifically or by implication any environmental or biological (e.g., mold, fungi, bacteria) assessment of the site or identification or prevention of pollutants, hazardous materials or conditions. If the owner is concerned about the potential for such contamination or pollution, other studies should be undertaken.

This report has been prepared for the exclusive use of our client for specific application to the project discussed and has been prepared in accordance with generally accepted geotechnical engineering practices. No warranties, either express or implied, are intended or made. Site safety, excavation support, and dewatering requirements are the responsibility of others. In the event that changes in the nature, design, or location of the project as outlined in this report are planned, the conclusions and recommendations contained in this report shall not be considered valid unless Terracon reviews the changes and either verifies or modifies the conclusions of this report in writing.

APPENDIX A

FIELD EXPLORATION

Source: USGS 7.5-Minute Topographic Maps Editions “Tolar SE”, New Mexico, United States, dated 2013.

Project Mngr:

Range Operations and Maintenance Facilities Melrose Range

Roosevelt County, New Mexico

SITE LOCATION MAP

MJD

Drawn By:

Checked By:

Approved By:

N/A

MEA

MEA

Project No.

66165043

Scale

File No.

Date:

As Shown

5/2016

4905 Hawkins, NE Albuquerque, New Mexico 87109

505.797.4287 Fax: 505.797.4288

FIG No.

A1

APPROXIMATE SITE

LOCATION

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Responsive ■ Resourceful ■ Reliable A3

Field Exploration Description

A total of 12 test borings were drilled at the site on May 3 and 4, 2016. The borings were drilled to depths ranging from approximately 3 to 31-½ feet below the ground surface at the approximate locations shown on the attached Site Location Map and Boring Location Plan. The test borings were located as follows:

Borings Location Depths (feet)

B-01 thru B-03 Planned Joint Operations Planning Facility 31 to 31-½

B-04 thru B-06 Planned Range Control Support Facility 31 to 31-½

B-07 thru B-09 Planned Range Maintenance Facility 30-½ to 31-½

P-01 thru P-03 Planned Leach Field Area 3

The test borings were advanced with a truck-mounted CME-75 drill rig utilizing 8-inch diameter hollow-stem augers.

The borings were located in the field by using the boring location plan provided by CH2M Hill and measuring from existing property lines. Coordinates at each boring location were determined from a hand-held GPS unit. The accuracy of boring locations should only be assumed to the level implied by the method used.

Lithologic logs of the borings were recorded by the field engineer during the drilling operations.

At selected intervals, samples of the subsurface materials were taken by driving split-spoon or ring-barrel samplers.

Penetration resistance measurements were obtained by driving the split-spoon and ring-barrel samplers into the subsurface materials with a 140-pound automatic hammer falling 30 inches per ASTM D1586. The penetration resistance value is a useful index in estimating the consistency or relative density of materials encountered.

A CME automatic SPT hammer was used to advance the split-barrel sampler in the borings performed on this site. The effect of the typical automatic hammer's efficiency has been considered in the interpretation and analysis of the subsurface information for this report.

Groundwater conditions were evaluated in the borings at the time of site exploration.

Percolation tests were performed within the borings located in the planned leach field area in general accordance with the EPA falling head percolation test procedure.

P-01

Depth of Test 36 in

Water Level

Time From top of hole (in)

Change in time

(time) Change in water (in)

Percolation Rate

(Time/in) 9:30:00 22 9:50:00 27 0:20:00 5 0:04:00

10:10:00 29 0:20:00 2 0:10:00 10:30:00 31 0:20:00 2 0:10:00 10:50:00 31.5 0:20:00 0.5 0:40:00 11:10:00 33 0:20:00 1.5 0:13:20 11:30:00 34 0:20:00 1 0:20:00 11:50:00 36 0:20:00 2 0:10:00

Average 0:15:20 Maximum 0:40:00

A16

Percolation Test Results 66165043

P-02

Water Level

Time From top of hole (in)

Change in time

(time) Change in water (in)

Percolation Rate (Time/in)

9:25:00 20 9:45:00 26 0:20:00 6 0:03:20

10:05:00 28 0:20:00 2 0:10:00 10:25:00 30 0:20:00 2 0:10:00 10:45:00 31 0:20:00 1 0:20:00 12:45:00 32 2:00:00 1 2:00:00 13:50:00 34 1:05:00 2 0:32:30

Average…