1.9.2_Geotechnical_Engineering_Report.pdf

Terracon Consultants, Inc. 4905 Hawkins NE Albuquerque, New Mexico 87109

P [505] 797 4287 F [505] 797 4288 terracon.com

Geotechnical Engineering Report Office, Visitor Center, and Site Improvements

Valle de Oro National Wildlife Refuge

7851 2nd Street SW

Bernalillo County, New Mexico

May 3, 2016

Terracon Project No. 66165036

Prepared for:

U.S. Fish & Wildlife Service

Albuquerque, New Mexico

Prepared by:

Terracon Consultants, Inc.

Albuquerque, New Mexico mailto:Jeffrey_johns@fws.gov

Geotechnical Engineering Report Office, Visitor Center, Site Improvements ■ Bernalillo County, New Mexico May 3, 2016 ■ Terracon Project No. 66165036

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 office, visitor center and site improvements to be located at the Valle de Oro National Wildlife Refuge (NWR) at 7851 2nd Street

SW in Bernalillo County, New Mexico. Terracon’s geotechnical scope of work included the advancement of five (5) test borings to an approximate depth of 21-½ 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 surface and near surface soils generally consisted of fat to lean clay with varying amounts of sand and gravel, silt with varying amounts of sand and gravel, and sand with varying amounts of clay, silt, and gravel. Groundwater was encountered at depths of about 5 to

15 feet below existing ground surface in the test borings at the time of field exploration. On-site sand, silt, and blended lean clay soils are suitable for use as engineered fill beneath foundations and floor slabs. On-site fat clay soils are not suitable for use as engineered fill under foundations or floor slabs. On-site clay soils will require additional effort, processing and moisture conditioning/drying out to provide a uniform engineered fill material. On-site soils are suitable for use below pavements. The shallow groundwater conditions and elevated moisture content of the subsurface soils will likely create potential workability issues during construction and will likely require more effort to provide a uniform blended engineered fill.

Due to the elevated moisture contents and shallow groundwater conditions encountered during the geotechnical exploration, soils exposed during construction may become unstable.

Overexcavation of wet zones and drying or replacement with granular materials, chemical treatment and/or the use of geogrid reinforcement may be necessary. In addition, temporary dewatering during construction may be required.

Foundations: The buildings at the site may be supported by shallow spread and continuous footings or monolithic slab with turned down edges bearing on compacted subgrade or engineered fill. Fill used to raise the site can be used as part of the minimum zone of engineered fill. Consideration should be given to performing overexcavation prior to site grading to avoid handling soil materials twice.

Floor Slabs: The on-site surface and near surface soils at existing moisture contents are expected to exhibit low to moderate expansive potentials when compacted and subjected to light loading conditions such as those imposed by floor slabs. Therefore, the floor slabs should be supported on a zone of engineered fill, provided that some movement can be tolerated. The engineered fill should consist of on-site sand, silt, and blended lean clay or imported soils as specified herein, on-site fat clay soils are not suitable for use as engineered fill. Fill used to raise the site can be used as part of the minimum zone of engineered fill.

Pavement Sections: Automobile parking areas – 3” AC over 6” ABC, 5” PCC over prepared subgrade; drives and truck access – 4½” AC over 6” ABC or 5½” PCC over prepared subgrade.

Borrow Sources: The soils encountered in the borrow areas typically consisted of silt and sand and are suitable for use as engineered fill. However, due to the shallow groundwater conditions encountered within the borrow area test borings (5 feet below existing ground surface), excavation depths may be limited and excavations may have to be extended laterally to avoid groundwater and unstable soil conditions.

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.

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 Typical Subsurface Profile

3.2 Groundwater

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 Grading and Drainage

4.2.7 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 Pavement

4.7.1 Design Recommendations

4.7.2 Materials Specifications

5.0 GENERAL COMMENTS

TABLE OF CONTENTS– continued

Exhibit No.

Appendix A – Field Exploration

Site Location Map ................................................................................................ A1

Boring Location Plan ........................................................................................... A2

Field Exploration Description ............................................................................... A3

Boring Logs ............................................................................................. A4 thru A8

General Notes ..................................................................................................... A9

Unified Soil Classification System ...................................................................... A10

Appendix B – Laboratory Testing

Laboratory Test Description ................................................................................. B1

Grain Size Distribution ............................................................................. B2 and B3

Consolidation Test Results ...................................................................... B4 and B5

Summary of Laboratory Results .......................................................................... B6

Chemical Test Results

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GEOTECHNICAL ENGINEERING REPORT

OFFICE, VISITOR CENTER, AND SITE IMPROVEMENTS

VALLE DE ORO NATIONAL WILDLIFE REFUGE

7851 2ND STREET SW

BERNALILLO COUNTY, NEW MEXICO

Terracon Project No. 66165036 May 3, 2016

1.0 INTRODUCTION

This report presents the results of our geotechnical engineering services performed for the proposed office, visitor center, and site improvements to be located the Valle de Oro National

Wildlife Refuge at 7851 2nd Street SW in Bernalillo County, New Mexico. The report addresses the following:

subsurface soil conditions foundation design and construction groundwater conditions floor slab design and construction earthwork pavement design and construction seismic considerations lateral earth pressures on-site borrow source suitability

Our geotechnical engineering scope of work for this project included the advancement of five (5) test borings to a depth of 21-½ 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 (Appendix

A)

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Structures

The project will include the construction of the following:

■ One-story, slab-on-grade office and visitor center approximately 8,000 square feet in plan area (one or more buildings)

■ One-story, slab-on-grade pre-engineered steel shop building approximately 2,000 square feet in plan area.

Building construction

■ Office and Visitor Center - Structural steel and metal stud

■ Shop Building - steel frame and metal skin

Proposed foundation

■ Office and Visitor Center – spread and continuous footings or monolithic slab with turned down edges

■ Shop Building - spread footings

Finished floor elevations (FFE) Approximately 4 feet above existing site grade

Maximum loads (assumed) Columns:

20 to 80 Kips

Walls:

1.5 to 4 Kips/lf

Slab:

150-250 psf

Site development

Site development will consist of the construction of asphalt and/or

Portland cement concrete paved parking areas and drives, sidewalks along with the installation of utilities

Grading Maximum fill depths of about 4 feet (assumed)

Cut and fill slopes Not applicable

Pavements

Asphalt concrete wearing surface

Standard Duty – Automobile parking

Heavy Duty – Drives and truck access

Borrow sources On-site on the west side and south site of the existing development

Free-standing retaining walls Not applicable

Below grade areas Not applicable

2.2 Site Location and Description

Location 7851 2 nd

Street SW in Bernalillo County, New Mexico

Existing site features

(site interior)

The majority of the site is vacant. Existing buildings, structures and storage tanks occupy the approximate ¼ of the NEC of the site. The Barr Interior Drain runs north-south through the center of the refuge. Underground utilities were observed in portions of the site.

Surrounding developments

North: Vacant undeveloped farmland

East: 2 nd

Street and residential development

West: Vacant undeveloped farmland

South: Vacant undeveloped farmland

Current ground cover Moderate to heavy growth of vegetation

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Existing topography Relatively level project site, existing roads are typically raised 1 to

3 feet above adjacent fields.

3.0 SUBSURFACE CONDITIONS

3.1 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 types; in-situ, the transition between materials may be gradual. Details for each of the borings can be found on the boring logs included in Appendix A of this report. Based on the results of the borings, subsurface conditions on the project site can be generalized as follows:

Description Approximate Depth to

Bottom of Stratum (feet) Material Encountered Consistency/Density

Stratum 1 4 to 13 Silt with varying amounts of sand and gravel.

Soft to Stiff

Stratum 2 4 to 21-½

Lean to fat clay with varying amounts of silt, sand, and gravel

Soft to Stiff

Stratum 3 4 to 21-½ Sand with varying amounts of clay, silt, and gravel

Very Loose to Medium

Dense

Borrow source soils are primarily comprised of silt with varying amounts of sand and sand with varying amounts of silt.

A slight hydrocarbon odor was observed in Boring No. B-05 near groundwater depth.

The shallow subsurface sand soils are non-plastic to medium in plasticity. The silt soils are non-plastic. The clay soils are medium 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 surface and near surface clay soils exhibit low to moderate compressibility/consolidation potentials at in-situ moisture contents. The test results indicate that the near surface clay soils have a low to moderate tendency for expansion and a low tendency for compression/consolidation when wetted under foundation loads.

Laboratory test results indicate that the surface and near surface sand soils exhibit low compressibility potentials at in-situ moisture contents. The test results indicate that the near surface sand soils have a non- tendency for expansion and a low to moderate tendency for compression when wetted under foundation loads. When water is added to samples of laboratory compacted near-surface soils, we anticipate that the compacted near surface sand

Responsive ■ Resourceful ■ Reliable 4 and silt soils will exhibit non- to low expansion potential and non- to low collapse potential when subjected to light loading conditions such as those imposed by floor slabs. We anticipate that the compacted clay soils will exhibit low to moderate expansion potential and low consolidation potential.

It should be noted that the existing moisture contents of the subsurface soils are relatively high and range from about 10% to 46% with the majority of the values in the 25% to 35% range.

Laboratory test results indicate that on-site soils exhibit soluble sulfate concentrations 21 to 230 mg/kg.

3.2 Groundwater

Groundwater was encountered at depths of about 5 to 15 feet below existing site grade in the test borings at the time of field exploration. 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 levels can be expected to fluctuate with varying seasonal and weather conditions.

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.

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. Shallow groundwater and potentially compressible and very loose to loose sand soils which show a tendency for compression/consolidation and lean to fat clays which show a tendency for low to moderate swell when elevated in moisture content, will require particular attention in the design and construction.

Groundwater was encountered at depths of about 5 to 15 feet below existing site grade in the test borings at the time of field exploration. Due to the shallow groundwater conditions and elevated moisture contents encountered in the subsurface soils during the geotechnical exploration, soils exposed during construction may be unstable. In addition, depending upon the depth of foundations, final grade elevations, and seasonal irrigation/weather variations, groundwater may be encountered in excavations which would require temporary dewatering during construction. Workability may be improved by scarifying and drying. Overexcavation of wet zones and replacement with granular materials may be necessary. Lightweight excavation

Responsive ■ Resourceful ■ Reliable 5 equipment may be required to reduce subgrade pumping. Use of lime, fly ash, kiln dust or cement 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.

Based on the geotechnical engineering analyses, subsurface exploration and laboratory test results, we recommend that the proposed building structures be supported on spread and continuous footings or monolithic slab with turned down edges foundation systems bearing on a zone of engineered fill. Slabs-on-grade bearing on engineered fill may be utilized for the interior floor systems, provided some movement can be tolerated and care is taken in the placement and compaction of the subgrade soil. Fill used to raise the site can be used as part of the minimum zone of engineered fill. Consideration should be given to performing overexcavation prior to site grading to avoid handling soil materials twice.

On-site sand, silt, and blended lean clay soils are suitable for use as engineered fill beneath the foundation/floor slab. On-site fat clay soils are not suitable for use as engineered fill under floor slabs or foundations. On-site clay soils will require additional effort, processing and moisture conditioning/drying out to provide a uniform engineered fill material. On-site soils are suitable for use below pavements.

The soils encountered in the borrow areas typically consisted of silt and sand and are suitable for use as engineered fill. However, due to the shallow groundwater conditions encountered within the borrow area test borings (5 feet below existing ground surface), excavation depths may be limited and excavations may have to be extended laterally to avoid groundwater and unstable soil conditions.

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 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.

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4.2.1 Site Preparation

Strip and remove vegetation, debris, and other deleterious materials from proposed building and traffic/pavement areas. Exposed surfaces should be free of mounds and depressions which could prevent uniform compaction.

Stripped materials consisting of vegetation and organic materials should be wasted from the site, or used to revegetate landscaped areas or exposed slopes after completion of grading operations. If it is necessary to dispose of organic materials on-site, they should be placed in non-structural areas, and in fill sections not exceeding 5 feet in height.

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 proposed building structures.

Evidence of underground facilities and utilities was observed during the site reconnaissance.

Therefore, such features could be encountered during construction. If unexpected fills or underground facilities 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.

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. Well points may be required for significant groundwater flow, or where excavations penetrate groundwater to a significant depth.

Due to the elevated moisture contents and shallow groundwater conditions encountered during the geotechnical exploration, on-site soils exposed during construction may pump or become unstable. 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 or cement 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 should extend below proposed foundations and floor slabs 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.

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Areas of soft or loose 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 loose soils should be removed and replaced as engineered fill or by other material meeting the specifications for engineered fill.

For placement of engineered fill below footings, the excavation should be widened laterally, at least eight inches for each foot of fill placed below footing base elevations.

Subgrade soils beneath foundations, interior and exterior slabs, and beneath pavements 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.

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.

Clean on-site sand, silt, and blended lean clay soils or 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 pavement areas floor slab areas foundation backfill

Clean on-site fat clay soils may be used as fill material for the following:

general site grading pavement areas

Some additional effort will likely be required for processing and moisture conditioning of the on-site clays to provide a uniform engineered fill material.

Imported soils for use as fill material within proposed building and structure 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

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No. 200 Sieve .............................................................................. 60 (max)

Liquid Limit ....................................................................... 35 (max)

Plasticity Index ................................................................. 15 (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.

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 ten inches loose thickness.

4.2.5 Compaction Requirements

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

Material Type and Location

Per the Modified Proctor Test (ASTM D 1557)

Minimum

Compaction

Requirement (%)

Range of Moisture Contents for

Compaction

Minimum Maximum

On-site soils or approved imported fill soils

Beneath foundations: 95 -0% +3%

Beneath slabs: 95 -0% +3%

Beneath pavement areas: 95 -0% +3%

Aggregate base

Beneath slabs: 95 -0% +3%

Beneath pavement areas*: 96 -2% +2%

Miscellaneous backfill 90 -0% +3%

*Per NMDOT Specifications

4.2.6 Grading and Drainage

All grades must provide effective drainage away from the buildings during and after construction. Water permitted to pond next to the building 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.

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Exposed ground should be sloped at a minimum 5 percent away from the buildings for at least 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 will be subject to post construction movement. Maximum grades practical should be used for paving and flatwork to prevent water from ponding near the building or these elements. 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. Roof down spouts or scuppers should extend a minimum of five (5) feet beyond exterior walls to prevent water from discharging adjacent to the foundation.

Planters located within five (5) feet of the structure should be self-contained to prevent water accessing the buildings and pavement/traffic subgrade soils. Moderate to high volume spray or drip style landscaped irrigation should not be used adjacent to the building. Roof runoff should be collected in drains or gutters. Roof drains and downspouts/scuppers (if applicable) should discharge a minimum of five (5) feet away from structure.

4.2.7 Corrosion Potential

Results of soluble sulfate testing (21 to 230 mg/kg) indicate that ASTM Type II Portland cement is suitable for all concrete on and below grade. Foundation concrete should be designed for moderate sulfate exposure in accordance with the provisions of the ACI Design Manual, Section

318, Chapter 4.

4.3 Foundation Recommendations

The building structures can be supported by a shallow, spread/continuous footing or monolithic slab with turned down edges foundation systems bearing on a zone of 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 or

Monolithic Slab with Turned Down Edges

Structure One (1)-story, at-grade buildings

Bearing Material Minimum 5 feet of engineered fill below foundations*

Allowable Bearing Pressure 1,500 psf

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Minimum Dimensions Columns: 24 inches

Walls: 16 inches

Minimum Embedment Depth Below Finished Grade Exterior - 18 inches

Interior – 12 inches

Total Estimated Settlement 1 inch

Estimated Differential Settlement ¾ inch in 40 feet under walls

¾ inch between columns

*Fill used to raise the site can be used as part of the minimum zone of engineered fill. Consideration should be given to performing overexcavation prior to site grading to avoid handling soil materials twice.

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.

Footings should be proportioned to reduce differential foundation movement. 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 operations 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

Foundations should bear on a minimum of 5 feet of engineered fill. Fill used to raise the site can be used as part of the minimum zone of engineered fill. Consideration should be given to performing overexcavation prior to site grading to avoid handling soil materials twice. Due to the elevated moisture contents and shallow groundwater conditions encountered during the geotechnical exploration, subgrade soils exposed during construction will likely be unstable.

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 or cement could also be

Responsive ■ Resourceful ■ Reliable 11 considered as a stabilization technique. Laboratory evaluation is recommended to determine the effect of chemical stabilization on subgrade soils prior to construction.

Areas of soft or loose 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 loose 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 inches for each foot of fill placed below footing base elevations.

4.4 Seismic Considerations

Groundwater was encountered at depths of about 5 to 15 feet below the ground surface in the borings. In addition, the site soils are primarily comprised of interbedded very loose to medium dense sands and soft to stiff clays. Based upon the subsurface soils, seismicity in the area, and the standard penetration resistance, it is our opinion that the liquefaction potential is relatively low to moderate depending upon the magnitude of the earthquake. The structural engineer should evaluate the relative liquefaction risk to the structures and design appropriately. A modification to the recommended IBC Site Class indicated below may be required.

The recommended seismic design parameters should be used in the design:

2012 International Building Code Site Classification (IBC) D

Site Latitude N 34.97995°

Site Longitude W 106.67095°

SMs Spectral Acceleration for a Short Period 0.674g

SM1 Spectral Acceleration for a 1-Second Period 0.314g

SDs Spectral Acceleration for a Short Period 0.449g

SD1 Spectral Acceleration for a 1-Second Period 0.209g

Fa Site Coefficient for a Short Period 1.421

Fv Site Coefficient for a 1-Second Period 2.239

Note: In general accordance with the 2012 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.

Note: The 2012 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 21-½ feet, and this seismic site class definition considers that medium dense 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.

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4.5 Floor Slab

4.5.1 Design Recommendations

Interior floor system Slab-on-grade concrete.

Floor slab support Minimum 3 feet of engineered fill*

Subbase Compacted subgrade

Modulus of subgrade reaction

150 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.)

*Fill used to raise the site can be used as part of the minimum zone of engineered fill.

Construction of floor slabs on engineered fills composed of on-site sands, blended clays and imported soils is recommended for the project.

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.

The use of a vapor retarder or barrier should be considered beneath concrete slabs-on-grade that will be covered with wood, tile, carpet or other moisture sensitive or impervious coverings, or when the slab will support equipment sensitive to moisture. When conditions warrant the use of a vapor retarder, the slab designer and slab contractor should refer to ACI 302 and ACI 360 for procedures and cautions regarding the use and placement of a vapor retarder/barrier.

4.5.2 Construction Considerations

Some 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, floor slabs should be supported on a minimum of 3 feet of engineered fill prepared as outlined in the Earthwork section of this report. Fill used to raise the site can be used as part of the minimum zone of engineered fill.

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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 and clayey sand soils

On-site non-plastic sands and imported soils

45 psf/ft

35 psf/ft

Passive Case On-site clay and clayey sand soils

On-site non-plastic sands and imported soils

325 psf/ft

400 psf/ft

At-Rest Case On-site clay and clayey sand soils

On-site non-plastic sands and imported soils

65 psf/ft

55 psf/ft

Coefficient of Base Friction On-site clay and clayey sand soils

On-site non-plastic sands and imported soils 0.35

Note: 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 Pavement

Due to the shallow groundwater conditions and elevated moisture contents encountered in the subgrade soils during the geotechnical exploration, soils exposed during construction may be unstable. 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 cement or geogrid could also be considered as a stabilization technique.

4.7.1 Design Recommendations

For new pavement areas, the design approach used to populate the table outlined below was based on the National Asphalt Pavement Association (NAPA), which is specific to low volume pavements. Portland Cement Concrete (PCC) pavement thicknesses were based on the

American Concrete Institute (ACI) design recommendations.

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The design of pavement thickness was based on the following:

■ Traffic Class I for the light duty traffic areas include a maximum of 7,000 design EALs

■ Traffic Class II for the heavy duty traffic areas include a maximum 27,000 design EALs

■ A soil characterization of “poor” to “fair” based on the clay and silt soils encountered at the site

■ A design life of 20 years

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

Traffic Area Alternative

Recommended Pavement Section Thickness (inches)

Asphalt

Concrete

Surface

Portland

Cement

Concrete

Aggregate

Base

Course

Total

Automobile

Parking Areas

A 3 -- 6 9

B -- 5* -- 5

Drives and Truck

Access

A 4-½ -- 6 10-½

B -- 5-½ -- 5-½

*Minimum per ACI

These pavement sections are considered minimal sections based upon the expected traffic and the existing subgrade conditions. However, they are expected to function with periodic maintenance and overlays if good drainage is provided and maintained.

Each alternative should be investigated with respect to current material availability and economic conditions.

4.7.2 Materials Specifications

The aggregate base course should consist of a blend of sand and gravel, which meets strict specifications for quality and gradation. Use of materials meeting New Mexico Department of

Transportation (NMDOT) Specifications is recommended. 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 96% of maximum dry density and within 2 percent of optimum moisture content as determined by AASHTO T180.

Asphalt concrete should be obtained from an approved mix design stating the properties, optimum asphalt content, job mix formula, and recommended mixing and placing temperatures.

Aggregate used in asphalt concrete should meet a particular gradation. Use of materials meeting NMDOT SP-III or SP-IV specifications is recommended. The mix design should be submitted prior to construction to verify its adequacy. The asphalt materials should be placed in

Responsive ■ Resourceful ■ Reliable 15 minimum and maximum lifts of about 1-½ and 3-½ inches, respectively, and should be compacted to a minimum of 92% and a maximum of 97% of maximum theoretical density

(ASTM D2041).

Preventative maintenance should be planned and provided for through an on-going pavement management program in order to enhance future pavement performance. Preventative maintenance activities are intended to slow the rate of pavement deterioration, and to preserve the pavement investment.

Preventative maintenance consists of both localized maintenance (e.g. crack sealing and patching) and global maintenance (e.g. surface sealing). Preventative maintenance is usually the first priority when implementing a planned pavement maintenance program and provides the highest return on investment for pavements.

Pavement design methods are intended to provide structural sections with adequate thickness over a particular subgrade such that wheel loads are reduced to a level that subgrade can support. The support characteristics of the subgrade for pavement design do not account for the shrink/swell movements of the soils encountered on this project. Thus the pavement may be adequate for a structural standpoint, yet still experience cracking and deformation due to shrink/swell related movement of the subgrade. It is, therefore, important to minimize moisture changes in the subgrade to reduce collapse/consolidation/expansion movements.

Future performance of pavements constructed at this site will be dependent upon several factors, including:

Maintaining stable moisture content of the subgrade soils.

Providing for a planned program of preventative maintenance.

The performance of all pavements can be enhanced by minimizing excess moisture which can reach the subgrade soils. The following recommendations should be considered at the minimum:

site grading at a minimum 2% grade away from the pavements;

the subgrade and the pavement surface have a minimum ¼ inch per foot slope to promote proper surface drainage.

consider appropriate edge drainage and pavement under drain systems, install pavement drainage surrounding areas anticipated for frequent wetting install joint sealant and seal cracks immediately, compaction of any utility trenches for landscaped area to the same criteria as the pavement subgrade.

seal all landscaped areas in, or adjacent to pavements to minimize or prevent moisture migration to subgrade soils;

Responsive ■ Resourceful ■ Reliable 16 placing compacted, low permeability backfill against the exterior side of curb and gutter; and placing curb, gutter and/or sidewalk directly on subgrade soils without the use of base course materials.

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 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 “Isleta”, New Mexico, United States, dated 2013.

Project Mngr:

Office and Visitor Center Improvements Valle de Oro National Wildlife Refuge

Bernalillo County, New Mexico

SITE LOCATION MAP

MJD

Drawn By:

Checked By:

Approved By:

N/A

MEA

MEA

Project No.

66165036

Scale

File No.

Date:

As Shown

4/2016

4905 Hawkins, NE

Albuquerque, New Mexico 87109

505.797.4287 Fax: 505.797.4288

FIG No.

A1

APPROXIMATE SITE

LOCATION

Project Mngr:

BORING LOCATION PLAN

Office and Visitor Center Improvements

Valle de Oro National Wildlife Refuge

Bernalillo County, New Mexico

A2 4905 Hawkins St. NE

Albuquerque, New Mexico 87109

Phone: 505.797.4287 Fax 505.797.4288

66165036

NTS

4/2016

MJD

MEA

MEA

B-01 Boring Location

B-04

N

B-03

B-05

B-02

B-01

Field Exploration Description

A total of five (5) test borings were drilled at the site on April 12, 2016. The borings were drilled to a depth of approximately 21-½ 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 and B-03 Office and Visitor Center Building Areas 21-½

B-05 Access Road 21-½

B-02 and B-04 Borrow Areas 21-½

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 proposed site plan of the site and measuring from existing property lines. Latitude and longitude were determined at each boring location using 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 each boring 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.

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 automatic hammer's efficiency has been considered in the interpretation and analysis of the subsurface information for this report.

Groundwater conditions were evaluated in each boring at the time of site exploration. Upon the completion of drilling operations, the borings were backfilled for safety considerations.

87 50-25-25

NP

3-9

4-5-5 N=10

1-1-1 N=2

2-2-4 N=6

2-3-2 N=5

4.0

9.0

13.0

21.5

FAT CLAY WITH SAND (CH), brown, stiff

POORLY GRADED SAND WITH SILT (SP-SM), trace gravel, brown, medium dense

SANDY SILT (ML), brown, soft groundwater encountered

SANDY LEAN CLAY (CL), brown, medium stiff

Boring Terminated at 21.5 Feet

Hammer Type: AutomaticStratification lines are approximate. In-situ, the transition may be gradual.

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4/

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SITE:

Advancement Method:

HSA

Abandonment Method:

Backfilled with soil cuttings upon completion.

4905 Hawkins St NE Albuquerque, NM

Notes:

Project No.: 66165036

Drill Rig: CME-75

Boring Started: 4/12/2016

BORING LOG NO. B-01

US Fish & Wildlife ServiceCLIENT:

Albuquerque, NM

Driller: EDI

Boring Completed: 4/12/2016

Exhibit: A-4

See Exhibit A-3 for description of field procedures.

See Appendix B for description of laboratory procedures and additional data (if any).

See Appendix C for explanation of symbols and abbreviations.

7851 2nd St SW Bernalillo County, NM

PROJECT: Office and Visitor Center Improvements

P E

R C

E N

T F

IN

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W A

T E

R C

O N

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ATTERBERG

LIMITS

LL-PL-PI

S A

M P

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W A

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R L

E V

E L

O B

S E

R V

A T

IO

N

S

D E

P T

H

F t.)

F

IE

LD

T

E S

T R

E S

U

LT

S

DEPTH

LOCATION See Exhibit A-2

Latitude: 34.979954° Longitude: -106.67095°

11 feet While drilling

WATER LEVEL OBSERVATIONS

NP

NP

3-4

0-1-1 N=2

1-1-1 N=2

3-2-2 N=4

2-2-1 N=3

4.0

8.0

21.5

SILTY SAND (SM), trace gravel, brown, loose

POORLY GRADED SAND WITH SILT (SP-SM), trace gravel, brown, very loose groundwater encountered

POORLY GRADED SAND (SP), trace gravel, brown, very loose to loose

Boring Terminated at 21.5 Feet

Hammer Type: AutomaticStratification lines are approximate. In-situ, the transition may be gradual.

G R

A P

H

IC

L O

G

T H

IS

B

O R

IN

G

L O

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IS

N O

T V

A

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IF

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P A

R A

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D F

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-N O

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6.

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T E

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A C

O N

.G

/1

SITE:

Advancement Method:

HSA

Abandonment Method:

Backfilled with soil cuttings upon completion.

4905 Hawkins St NE Albuquerque, NM

Notes:

Project No.: 66165036

Drill Rig: CME-75

Boring Started: 4/12/2016

BORING LOG NO. B-02

US Fish & Wildlife ServiceCLIENT:

Albuquerque, NM

Driller: EDI

Boring Completed: 4/12/2016

Exhibit: A-5

See Exhibit A-3 for description of field procedures.

See Appendix B for description of laboratory procedures and additional data (if any).

See Appendix C for explanation of symbols and abbreviations.

7851 2nd St SW Bernalillo County, NM

PROJECT: Office and Visitor Center Improvements

P E

R C

E N

T F

IN

E

S

W A

T E

R C

O N

T E

N T

D R

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IT

W E

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T pc f)

ATTERBERG

LIMITS

LL-PL-PI

S A

M P

LE

T

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E

W A

T E

R L

E V

E L

O B

S E

R V

A T

IO

N

S

D E

P T

H

F t.)

F

IE

LD

T

E S

T R

E S

U

LT

S

DEPTH

LOCATION See Exhibit A-2

Latitude: 34.981188° Longitude: -106.675498°

5 feet While drilling

84 32-20-12

44-23-21

2-2-2 N=4

2-1

2-2-2 N=4

1-1-2 N=3

4-6-4 N=10

8.5

17.5

21.5

CLAYEY SAND (SC), trace gravel, brown, very loose to loose, thin interbedded sand and clay layers

SANDY LEAN CLAY (CL), brown, soft, with interbedded sand…