am4_geotech.pdf

GEOTECHNICAL ENGINEERING INVESTIGATION

UTILITY FOR INDUSTRIAL INFRASTRUCTURE COMPLEX

PN 69286, FORT BLISS, TEXAS

Client

JACOBS – HUITT-ZOLLARS (JV)

EL PASO, TX

Consultant

ARCHANA USA, INC.

EL PASO, TX.

ARCHANA PROJECT NO.: AGJ-10-023

August 24, 2011

August 24, 2011

Jacobs – Huitt-Zollars (JV) 1717 McKinney Avenue, Suite 1400 Dallas, TX 75202-1236

Attn. Mr. Scott Graves, P.E

Subject: Geotechnical Engineering Investigation

Industrial Infrastructure Complex –PN 69286 Fort Bliss, Texas

Jacobs – Huitt-Zollars Project No: 83X87101 Prime Contract No: W9126G-08-D-0001 with U.S.A.C.E Archana Project No.: J10-023

Dear Mr. Graves:

We are pleased to submit our final geotechnical report for the subject project. This report includes all the comments that were conveyed to us from time to time in emails and telephone discussions. This report supersedes all the previously issued reports, recommendations, letters, email write-ups and memos. This report is prepared in accordance with the mutually agreed upon scope of services, as described in Archana USA, Inc. proposal No. APGN-10-023 dated September 17, 2010. A notice to proceed was given to us on December 22, 2010.

This report contains information to be utilized in the design of foundation and pavement systems associated with the above project. Please contact us if you have any questions or need further assistance in connection with this project. We look forward to collaborating with you during the construction phase of this important project.

Respectfully submitted, ARCHANA USA, INC. Peer Reviewed By, B. Krishna Goparaju, Ph.D., P.E. Pratap G. Reddy, Ph.D., P.E.

Corporate Consultant President cc: Above to:

Mr. Steve Pitts (by email)

Ken Johnson (by email) Sanford Case (by email) Tami White (by email)

Archana Project No. J10-023 Utility for Industrial Complex Infrastructure PN 69286 Fort Bliss, Texas ii

EXECUTIVE SUMMARY

Jacobs-Huitt Zollars (JV) has authorized Archana USA, Inc., to perform a geotechnical investigation for the proposed Utilities for Industrial Complex Infrastructure project (PN 69286), Fort Bliss, Texas, on December 22, 2010 in accordance with the scope of work agreed in Archana’s Proposal (APGN-10-0230). This report should be reviewed and used in its entirety.

The project site for the proposed Utility project is located in an open area east of Brigs Army Airfield near the intersection of SPUR 301 and Purple Heart Boulevard, El Paso, Texas. The site facilities will include one (1) building for Defense Reutilization and Manufacturing (DRMO) facility, six (6) warehouse buildings for Standardization Supply and Activity (SSA), two (2) units of maintenance buildings & one (1) Fire Station building, one (1) substation facility and driveways connecting all the facilities with parking and open storage areas.

Scope of work under this project is accomplished by performing a total of 90 geotechnical borings, 32 Dynamic Cone Penetrometer (DCP) tests, thirteen (13) Soil resistivity tests and fourteen (14) percolations tests and two (2) thermal resistivity tests in addition to testing for identification and classification of recovered soil samples. Number of borings, their locations and depth were selected by the client. Results of field investigations and laboratory test results are presented in boring logs generated in USACOE format. Test results of soil resistivity, Percolation tests and thermal resistivity tests were presented in separate tables at the end of the report. Results of Standard Penetration Test (SPT) blow counts and DCP tests were presented in separate charts and tables.

Based on the Geologic Map of Texas, El Paso sheet, the project site area appears to be located in formations known as Young Quaternary deposits (QB) and Wind Blown deposits (QWs) consisting of Lacustrine and Fluviatile deposits of Clay, Sand, Silts and Gypsum. Based on the results of field exploration, laboratory testing, it is observed that the site soils essentially consists of medium dense to very dense silty sands, poorly graded sands with silts, sandy silts with layers of clayey sands and fat clays at various depths. Groundwater is not encountered in the geotechnical borings during drilling or 24 hours after drilling.

Based on the resistivity testing results, the corrosivity of site soils were observed to be mildly corrosive to highly corrosive. Recommendations were provided for additional testing to ascertain site corrosion potential more accurately.

Engineering analyses were performed and recommendations were provided for allowable bearing capacities for shallow footings the selected foundation type for most buildings and stiffened slab on grade foundations for VMF building. Recommendations for drilled shaft foundations were also provided for Lighting Masts, Lighting Poles and Bus Duct Supports near substation building.

Design recommendations for pavement design (flexible and rigid) and construction were provided.

Steepest stable slopes for the proposed detention ponds up to a maximum depth of 10 feet were provided including recommendations for erosion control and protection of side slopes.

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TABLE OF CONTENTS

1.0 GENERAL

1.1 OBJECTIVE

1.2 SCOPE OF SERVICES

1.3 AUTHORIZATION

1.4 STANDARD OF CARE

2.0 PROJECT DESCRIPTION

2.1 PROPOSED WORKS AND IMPROVEMENTS

3.0 FIELD INVESTIGATION AND SOILS TESTING

3.1 FIELD EXPLORATION

3.2 SOILS LABORATORY TESTING

3.3 DYNAMIC CONE PENETRATION TESTING

3.4 SOIL RESISTIVITY TESTS

3.5 THERMAL RESISTIVITY TESTS

3.6 PERCOLATION TESTS

4.0 SITE GEOLOGY

4.1 SUBSURFACE SOIL FINDINGS

4.2 GROUNDWATER

5.0 ENGINEERING ANALYSIS AND RECOMMENDATIONS

5.1 FOUNDATION DESIGN RECOMMENDATIONS

5.1.1 Allowable Bearing Capacity for Shallow Foundations:

5.1.2 Slab on Grade Foundations:

5.1.3 Floor Slabs

5.1.4 Foundation for VMF Building

5.1.3 Deep Foundations for Lighting Masts, Poles and Bus Duct Support Structures

5.1.4 Construction Specifications for Drilled Shafts:

5.2 STRUCTURAL FILL AND SUBGRADE PREPARATION

5.3 EXCAVATION

5.4 PAVEMENT RECOMMENDATIONS

5.4.1 Rigid Pavement Parameters:

5.4.2 Rigid Pavement Recommendations:

5.4.3 Rigid Pavement Construction Guidelines

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5.5 FLEXIBLE PAVEMENTS

5.6 PAVEMENT SUBGRADE PREPARATION

5.7 DRAINAGE AND GROUNDWATER CONSIDERATIONS

6.0 DETENSION BASINS

7.0 CORROSION PROTECTION OF FOUNDATIONS

8.0 TESTING REQUIREMENTS

1.0 General

This geotechnical engineering report has been prepared for the exclusive use of Jacobs – Huitt- Zollars, a Joint Venture (CLIENT) and Department of the Army, Fort Bliss, Texas, in connection with the Utility Project for Industrial Infrastructure Complex.

The project site of the Utility for Industrial Infrastructure is approximately an open land area with brush, plants and tall grass, approximately located in east of Biggs Army Airfield which is near the intersection of SPUR 601 and Purple Heart Boulevard, El Paso, Texas. Surrounding land usage is commercial and vacant lands. A site vicinity map is provided in Figure 1.

The Utility project includes construction of facilities for various buildings, an electrical substation, two (2) detention basins, driveways and parking lots. This report includes recommendations for building foundations, pavement for driveways and parking areas, safe side slopes for detention basin construction, and results of associated field and laboratory exploration.

1.1 Objective

The primary objective of this study is to characterize subsurface soils of the site, perform geotechnical borings, field testing such as Dynamic Cone Penetrometer (DCP) testing, Standard Penetration Testing (SPT), Electrical Resistivity & Percolation Tests at selected locations, laboratory testing on soil samples recovered in geotechnical borings, geotechnical engineering analyses and develop geotechnical recommendations for design and construction of the project facilities.

1.2 Scope of Services

The scope of services for the proposed Utility for Industrial Complex Project includes the implementation of a geotechnical field and laboratory program described in our proposal No.

APGN-10-0230 dated September 17, 2010.

The field program included performing soil borings, SPT Tests, DCP tests, Electrical Resistivity Tests and Percolation Tests near locations selected by the CLIENT, performing laboratory tests to characterize the site soils, perform engineering analyses and provide engineering recommendations for the project facilities.

1.3 Authorization

Archana USA, Inc. was authorized to perform geotechnical services pursuant to the agreed-upon Scope of Services and a notice to proceed dated December 22, 2010.

1.4 Standard of Care

Our geotechnical engineering services were conducted in a manner consistent with a level of care and skill that is congruent with those employed by other members of the geotechnical engineering community in our geographical area at the time our services were performed. This scope of services is of a limited nature.

Hence, the recommendations presented herein are based on the general assumption that subsurface conditions do not vary significantly from those encountered in the boring locations at the time the exploration was conducted. Further, subsurface soil conditions variations may not become evident until construction commences. In the event that subsurface soil conditions vary from those conditions discussed within the context of this report, Archana USA, Inc. should be notified immediately so that we can make an assessment of the significance of such variations.

2.0 PROJECT DESCRIPTION

The following sections provide an overview of our project understanding.

2.1 Proposed Works and Improvements

The proposed Utility project for Industrial Infrastructure Complex includes several single story buildings, an electrical substation, two detention basins, driveways that connect the site facilities and parking areas for open storage yard and vehicular traffic.

The site facilities will include: one (1) building for Defense Reutilization and Manufacturing (DRMO) facility on the east side, six (6) warehouse buildings for Standardization Supply and Activity (SSA) on the east side, two (2) units of maintenance buildings and one (1) Fire Station building on the south side, one (1) substation facility on the northeast side and driveways connecting the site facilities with parking and open storage areas. Based on the information provided to us, most of the buildings will consist of pre-engineered metal warehouse units.

According to the information available to us, the DRMO building is high bay pre-engineered building about 33,681 sq. ft. A Brass pre-engineered metal building about 9,000 sq. ft. is also proposed for the project.

All the SSA buildings will be pre-engineered metal building system approximately 20,640 sq. ft.

each in area with arrangement for administrative spaces.

The substation building at the northeast of the site is a single story metal building about 2,400 sq.

ft. in area with masonry walls supported by strip footings. In addition to the building at this area, electrical switch gears will be installed. Superimposed loads provided for these facilities are very light in magnitude.

Anticipated traffic counts on the driveways or roadways were provided to us which include 18 wheeler trucks, fire trucks and UPS / FEDEX trucks. Additional information is also provided about government vehicle loadings (tanks) anticipated for some of the parking areas and tank trails design in the project site. Necessary information for the design of flexible and rigid pavement options have been assumed appropriately.

3.0 FIELD INVESTIGATION AND SOILS TESTING

In accordance with the project layout information, we implemented a field sampling/testing and laboratory analytical program that reflects a scope developed by Jacobs – Huitt-Zollars.

3.1 Field Exploration

The field investigation consisted of performing geotechnical borings at selected locations and sampling in general accordance with ASTM D-1586. The boring locations were selected by the CLIENT, and were marked in the field by Huitt-Zollars. Geotechnical borings were performed by our subcontractor Raba-Kistner Consultants, Inc., utilizing a truck mounted drilling rig model CME

75. Both cohesive and granular soil samples were obtained utilizing a spilt spoon sampling procedure and performing a Standard Penetration Test with measurement of blow counts at each sampling location. Dynamic Cone Penetration (DCP) tests were also conducted at selected locations as per the requirements of the CLIENT or Lead Design Engineer (LDE). DCP tests are done by KSE (Kessler’s) model DCP Penetrometer; model no K-100 in accordance with ASTM D6951.

Borings are identified as per the requirements of Scope of Work Document, Section L, Item 3.

Boring locations and surface elevations at the boring locations were provided to us by the LDE.

Boring location maps are presented on Figure 2A thru Figure 2F.

A total of 90 borings and 32 Dynamic Cone Penetrometer (DCP) Tests were performed as shown on the boring location maps. A total of thirteen (13) soil resistivity tests were performed at selected locations as shown in Figure 2G. Fourteen (14) percolations tests were performed at the proposed detention basin site locations.

Summary of Boring Locations Coordinates and Surface elevations as provided to us by the client are presented in Table 1. The results of our DCP Tests, Soil Electrical Resistivity Tests and Percolations Tests are presented in Tables 2, 4, and 6 respectively in USACOE Form 1836 format. Charts are developed for SPT Tests and DCP Tests which are presented on Figures 5 and 6 respectively.

3.2 Soils Laboratory Testing

Upon completion of the field subsurface exploration, the soil samples were transported to our testing facilities. A testing program was developed and implemented to identify the soil types, relevant features and properties to be used in our geotechnical analysis. The following tests were conducted:

Table 1: Number of Laboratory Tests

Type of Test Number of

Tests Sieve Analysis (ASTM D 422) 266 Atterberg Limits (ASTM D4318 - Method B) 266 Moisture Contents (ASTM D 2216) 266

Type of Test Number of

Tests USCS Soil Classification (ASTM D2487) 266 Electrical Resistivity Tests (Field) 13 Field Soil Thermal Resistivity 2 Dynamic Cone Penetrometer Tests (DCP) 32 Field Percolation Tests 14

The results of our laboratory testing are presented on Tables 3 through 5. Charts were developed for sieve analyses which are presented on Figure 7.

3.3 Dynamic Cone Penetration Testing

Results of our DCP Tests are presented in Table 2. Based on known correlations for DCP, CBR values were estimated. Charts were prepared for DCP values with depth for each of the building areas on the project site which would enable to evaluate general variability of site specific average DCP values in mm/blow with depth. The site specific DCP charts are presented on Figure 6.

3.4 Soil Resistivity Tests

Soil Electrical Resistivity Tests were conducted based on the Wenner Four Electrode Method, in accordance with ASTM G57-95a (2001) at selected locations for the utility structures on the site.

A total of Thirteen (13) Soil Resistivity Tests were performed at selected locations as shown on Figure 3G to develop recommendations for corrosion potential of subsurface soils. The Resistivity Test results are presented in Table 4.

3.5 Thermal Resistivity Tests

Thermal Resistivity tests were performed on soil samples recovered from borings 8A2S-082 (substation facility) at a depth of 4 feet and at boring location 10A2S-010 (on road way near SSA buildings) at a depth of 1.5’ in our laboratory in accordance with ASTM D5334. Test results are presented on Table 5.

3.6 Percolation Tests

Percolation tests are done in accordance with ASTM D 5126, at the location of two (2) detention basins to analyze the water retention capacity of subsurface soils at in the detention basin area. A total of Fourteen (14) Percolation tests were performed for analyzing the permeability characteristics of subsurface soils near detention basin sites. A map showing the location of percolation tests is presented in Figure 2H. Results of Percolation tests are presented on Table 6A, 6B and 6C.

4.0 SITE GEOLOGY

Based on the Geologic Map of Texas, El Paso sheet, the project site area appears to be located in formations known as Young Quaternary deposits (QB) and Wind Blown deposits (QWs). Young Quaternary deposits consist of Lacustrine and Fluviatile deposits of Clay, Sand, Silts and Gypsum in bolsons, while the Wind Blown Sand deposits consist of sand and silt in sheets; locally includes cover sands, dunes and dune ridges. The geologic map of this project site is provided in Figure 3.

4.1 SUBSURFACE SOIL FINDINGS

The site subsurface conditions for the proposed Fort Bliss Utility for Industrial Infrastructure Project area is presented below based on the findings in our Geotechnical borings. Separate Soil profile sections were developed for all the facilities as presented in Figure 4A thru 4F. The results of our field exploration are summarized below.

SSA Buildings:

Based on elevations near the borings at this location, the topography appears to be relatively level with surface elevations varying from +3988 to +3989 feet above MSL. Soil conditions near the SSA buildings are evaluated based on borings 8A2S-031 thru 8A2S-033 and 10A2S-046 thru 10A2S-048 as shown along sections DD and EE (Figure 2D). Soil Profiles developed based on these borings can be found in Figures 4B and 4C. The subsurface soils at this site include medium dense to very dense cohesionless granular deposits (silty sands, sandy silts and poorly graded silts and sands) to a depth of about 20 feet, the maximum depth of exploration. In many of the soil borings, the silty sand deposits appear to be very dense with blow counts exceeding 50 below a depth of 10 to 12 feet. Layers of medium plasticity to high plasticity cohesive soils (clayey sand, sandy clay and fat clay) 2 to 3 feet thick were encountered at various depths. A layer of medium dense to very dense caliche 2½ to 5 feet thick is encountered at a depth of 5 feet in borings 8A2S-043 and 10A2S-048. A layer of loose silty sand, about 2 feet thick with blow count of 6 is encountered at a depth of 10 feet in boring 8A2S-042.

South Side (TMF/EMF and Cartridge Storage) Buildings:

Based on surface elevations at borings for this facility, it is observed that the ground surface elevation at this building site varies from +3986 feet (above MSL) on the north side to +3992 feet (above MSL) on the south side, a difference of about 5 feet. It is not known if fill will be used to raise the grade at this time. Subsurface soil conditions near the south side buildings were explored based on borings 8A2S-031 thru 8A2S-037 as shown in soil profiles along section FF (Figure 4D). The subsurface soils at this site are observed to be medium dense to dense brown alternating layers of silty sands, clayey sands, sands and sands with silt. The SPT N values ranged from 10 to 30 blows/foot for the shallow depths (0’ to 5’) below which most of the sands are dense. SPT below a depth of 15 feet to 17.5 feet met refusal (N > 50 blows/3 to 6 inches).

Borings 8A2S-035 thru 8A2S-037 indicated the presence of Clayey Sand Layers about 2 feet thick with alternating layers of Sands and Silts with percentage fines varying in the range 5% to 38%. Liquid Limit and Plasticity Index values for Clayey Sands ranged from 25 to 58 and 8 to 47 respectively.

DRMO Buildings:

The surface elevation within the building area appears to vary from +3985 to + 3988 above MSL with a difference of about 3 feet while the surface elevation surrounding the building area appear to vary from +3985 to +3992 feet above MSL. At this time, it is not known if fill will be used to raise the grade for uniform elevation.

The subsurface soil conditions at this location are evaluated based on borings 8A2S-044, 8A2S- 045 (building area), 10A2S-065, 10A2S-066, 10A2S-067, 10A2S-072 and 10A2S-073 (surrounding areas). Soil profiles were developed utilizing these borings as shown in sections I-I and H-H (Figure 2E and Figure 4F). The soil stratification in this location includes alternating layers of dense to very dense silty sand and clayey sand with SPT N values varying from 11 to 50+ and percent fines varying from 20% to 27%. The plasticity indices of clayey sands varied from 27 to 30.

Substation Facilities:

The surface elevation within the building area at this site varied from +3996 to +3998 feet above MSL. The subsurface soils are explored by drilling two borings 8A2S-082 and 8A2S-083 to a depth of 41½ feet below existing grade, which included essentially medium dense to dense and very dense silty sands, poorly graded silts and clayey sands. SPT-N values for the silty sands ranged from 6 to 45 to a depth of 17.5 feet and over 50 below 17½ feet with percent fines ranging from 9 to 27%. Clayey sand layers about 2 to 3 feet thick were encountered at a depth of 10 feet and 32½ feet below existing grade in boring 8A2S-083. Clayey sands were found to exhibit a plasticity index of 11 and percent fines 28%.

Detention Basins:

Subsurface soil conditions for the basins were evaluated utilizing borings 8A2S-081, 8A2S-086 through 8A2S-089(southwest detention basin) and 8A2S-080, 8A2S-084, 8A2S-085 (west Detention Basin) as shown in sections AA, BB and CC (Figure 2D, Figure 4A).

Based on surface elevations near the borings at these facilities, the existing ground surface elevations near the southwest detention basin appears to vary from +3984 to +3986 feet above MSL. The subsurface soils include medium dense to very dense silty sands, poorly graded sands and silts with gravel to a depth of 25 feet. A layer of cohesive soil deposit including clayey sand and fat clays was encountered between depths of 5 to 12½ feet below the existing ground level which has a plasticity index of 16.

The ground surface elevation for the west side basin appears to vary from +3982 to +3984 feet above MSL. The subsurface soils at this location include medium dense to very dense silty sands, poorly graded silts, sands. A medium plasticity clayey sand (0’ to 2.5’) layer and a high plasticity cohesive layer of sandy clay and clay are encountered between 5 to 7½ feet in borings 8A2S-080 and 8A2S-85.

Roadways:

Subsurface soil conditions under the proposed roadways were evaluated utilizing borings 10A2S- 001 through 10A2S-030. These borings were drilled to a depth of 11½ feet each below existing subgrade. Based on the survey information available at the boring locations, the surface elevations along the roadway appear to vary from +3977 to +4004 feet above MSL. The subgrade soils along the roadways include mostly medium dense to very dense silty sands, poorly graded sands and hard silts to a depth of 11 feet below existing grade.

A layer of low to medium plasticity clayey sand and sandy clay, 2½ to 5 feet in thickness was also encountered in most of the borings in the roadway. The top 2 to 3 feet of subgrade soils were observed to be low to medium dense sixty sands in borings 10A2S-001 to 10A2S-008, 10A2S- 016, 10A2S-020, 10A2S-022 and 10A2S-029. Subsurface soils in borings 10A2S-24 and 10A2S- 025 are observed to be very loose to loose in consistency between 2 feet to 10 feet below existing grade. Majority of the borings exhibited medium dense to very dense silt sands and clayey sands below an average depth of 5 feet from the existing grade. Considering the relatively heavy traffic loads, top 2 to 3 feet of subgrade should be stabilized by utilizing a lime fly ash admixture ((3%:8% respectively by dry weight) , excavating and re-compacting to 95% maximum dry density determined by ASTM D 1557 in loose lifts of 8 inches.

Soil Site Class for Seismic Design:

Based on the soil profiles, SPT blow count values and corresponding relative densities, the value of Soil Site Class for seismic design may be assumed as type 'D.'

4.2 Groundwater

Groundwater was not observed during or immediately following the drilling operations. However, it is important to note that groundwater levels may be present following significant rainfall events.

Furthermore, groundwater levels may be affected by on-site activities or grading changes to the site’s original topography.

5.0 ENGINEERING ANALYSIS AND RECOMMENDATIONS

The recommendations presented herein are based on the results of our subsurface exploration, soil mechanics laboratory testing, our engineering analysis of the aforementioned data, and our experience with similar soil conditions and the project characteristics.

The subject utility project for Industrial Complex includes Warehouse Buildings known as SSA Buildings, Tier 3 Maintenance Facility (TMF) /Electronics Maintenance Facility (EMF) buildings on Southside, DRMO buildings, Substation facilities and Detention basins in addition to roadways, parking areas and open storage yards. Below given are recommendations for design and construction of various facilities.

5.1 Foundation Design Recommendations

Based on the information made available to us, we understand the desired foundations for the proposed Warehouse buildings are shallow spread footings and strip footings. Engineering analyses were carried out to estimate allowable bearing capacities based on allowable settlements in non-cohesive soil deposits for the buildings.

Description of various buildings utilized in this project is provided below:

i) SSA Buildings:

Building Type: Pre-engineered Single Story Metal Building Total Construction Area: 20,640 Square feet each

ii) DRMO Building:

Building Type: Pre-engineered Single Story Warehouse Metal Building Total Construction Area: 33,681 Square feet

iii) EMF/TMF Buildings:

Building Type: Pre-engineered Single Story Metal Building Total Construction Area: 9000 Square feet each (45’ x 200’)

iv) All Other Buildings:

Building Type: Pre-engineered Single Story Metal Buildings with Combination of metal panels, EIFS and or Brick

v) Substation Facility:

Building Type: Bar Joist/Metal Deck Roof; 12-inch Load Bearing Walls w/Strip Footings under walls, Single Story

Total Construction Area: 2,624 Square feet (64’ X 41’) Concentrated Loads: 2000 Lbs Wall Bearing Loads: DL = 1900#/Ft, LL=400#/ft Electrical Switch Gear: 3500 Lbs/section (over 24 sq.ft) Switch Gear Battery Strings: 2,900 Lbs/each (over 12.28 Sq.ft)

Except for electrical substation building, superimposed structural loads were not available for the proposed building facilities.

5.1.1 Allowable Bearing Capacity for Shallow Foundations:

Net allowable bearing capacities for spread footings and strip footings are estimated based on an allowable total settlement of 1-inch in sands. SPT-N blow count profiles were developed for each of the building sites to evaluate design parameters for the purpose. Design SPT-N blow count value is determined based on the minimum blow count value encountered within a depth of 8 to 12 feet (2 to 3 times the width) in the borings. This design SPT-N value is then corrected to account for effect of overburden pressure (N60) to estimate the net allowable bearing capacity for spread footings in granular soils. Allowable bearing capacity value is also estimated based on Terzaghi’s generalized bearing capacity equation for spread footings and strip footings. Allowable bearing capacity value is then recommended based on whichever method yields the lowest value.

Recommendations are also provided for thickened slab on grade foundations based on BRAB report 33.

Based on known subsurface soil conditions and SPT-N profiles near the building sites, recommended net allowable bearing capacity values for spread foundations and strip footings founded at a depth of 3 feet below existing grade are summarized below. It is assumed that the width of footing will not exceed 4 feet. This includes a safety factor of 3.

i) SSA Buildings:

Allowable Bearing Capacity: 3000 PSF

ii) DRMO Building:

Allowable Bearing Capacity: 3100 PSF

iii) EMF/TMF Buildings:

Allowable Bearing Capacity: 2300 PSF

iv) All Other Buildings:

Allowable Bearing Capacity: 2000 PSF

v) Substation Facility:

Allowable Bearing Capacity: 2500 PSF

However, as mentioned in Section 4.1, the surface elevation at the south side buildings appear to vary by about 5 feet where as the surface elevations at DRMO building appear to vary by about 3 feet with in the building area and about 7 feet between the building and the surrounding open storage and parking areas. If fill will be used to raise the grade to a uniform surface elevation for building slabs, we recommend using drilled straight shafts designed for an allowable bearing capacity of 3000 PSF (Factor of safety = 3) founded at a depth of 2 to 3 feet below the originally existing grade (not the fill surface). Skin friction may be disregarded in this case.

Fill should be placed in loose lifts of 8 inches and compacted to 95% of maximum dry density estimated by Standard Proctor’s Test (ASTM D 1557) within -2% to +3% of optimum moisture content. Structural Fill utilized for raising the grade should have a plasticity index between 7 and 20 with its liquid limit less than 40. The horizontal limits of compacted structural fill should extend to at least 5 feet beyond the footing edge.

5.1.2 Slab on Grade Foundations:

If Stiffened Slab on Grade Foundations will be utilized over the compacted fill, grade beams should be designed for an allowable bearing capacity of 2000 PSF. Grade beams should be extended to a depth of at least 18 inches below final grade. Grade beam’s width and depth should be designed by structural engineer to serve as spread/strip foundation at concentrated load areas.

Fill placement under these foundations should be properly compacted in accordance with recommendations provided in Section 5.2 below.

5.1.3 Floor Slabs

Floor slabs for the proposed facility buildings may consist of conventional slabs (steel-bar reinforced) and should be constructed on a minimum of 12 inches of compacted select structural fill. Based on the subsurface soils encountered, we anticipate the potential for PVR value to impact the performance of floor slab to be low and hence we do not recommend any PVR reduction methods.

5.1.4 Foundation for VMF Building

Based on the discussions held in a teleconference on June 28, 2011 between Archana, Jacob and the Structural Engineer for the project, we were requested to provide recommendations for shallow stiffened slab-on-grade type of foundation with thickened slab is the preferred type of foundation for the VMF building. Based on the topographical map provided to us, the existing topography at the subject building is observed to vary between elevations +3986 to +3991.8, a difference of about 6 feet which will be raised to the finished grade utilizing properly compacted structural fill.

Foundation Plans for the TEMF/VMF building and typical section details (SB101, SB102, SB103, SB302, SB501, SB502, SB503 and SB 601 dated May 23, 2011) were provided to us for necessary information. The finished floor level considered for this building will be +3991.8. A review of the above drawings revealed the building will be supported by shallow footings. The slab will be stiffened by thickening the slab (stiffening beams) to support walls and columns where needed.

Stiffening beams will be placed at a depth between 3 feet and 4 feet below the finished floor level with the thickness of slab varying from 1 to 2 feet. Some of the footings are lowered to a depth of 6 to 7 feet to support bollards and elevator pits.

Stiffened Slab on Grade Foundation:

Based on the information thus available, stiffened slab on grade foundations will be placed within the compacted fill soils between elevations +3986 and +3991.8 for this building with stiffened portions (stiffener beams) under loaded structural load areas like columns and walls. Stiffened portions of the slab should be designed for an allowable bearing capacity of 2000 PSF which includes a factor of safety of 2.0. The minimum depth of the thickened portion of slab (stiffening beams) should be 24 inches below compacted final grade. Stiffening beam’s width and depth should be designed by structural engineer to serve as spread/strip foundation at concentrated load areas.

Fill soils placed to raise the ground surface to finished floor level should be compacted to a minimum of 95% maximum dry density in accordance with recommendation for Slab on Grade Foundation provided in Section 5.1, Page 15 of the Draft Geotechnical Report. A vapor barrier consisting of six-mil plastic sheeting should be placed under concrete slab. The excavations for the thickened beams should be clean and free of any loose materials prior to concrete placement.

Shallow Footings:

Depending on specific location of the footing within the building plan area, these footings will be placed at a depth of 6 to 7 feet and are likely to be resting within the compacted fill or in the existing natural subgrade soils. These footings may be designed for an allowable bearing pressure of 2000 psf which includes a safety factor of 2.0. The footings should be sized such that the pressure distribution across the entire building area (all the footings) will be uniform.

Foundations for elevator pits and such similar features with cavities below the finished floor level should be designed for resisting uplift pressure from groundwater table which should be assumed at the finished surface. For stability against uplift, weight of foundation and any retained soil within the vertical surface along edges of extended footings (if any) may be considered to resist the uplift pressure. Skin friction contribution along vertical surfaces of footing walls should be disregarded in estimated safety factor against uplift. Factor of safety against uplift should be a minimum of 1.2.

Walls for the lowered footings with cavities (elevator pits) will be subjected active earth pressures and should be designed to resist such earth pressures. Equivalent fluid weight of 150 pcf may be used for estimating the earth pressure under saturated ground conditions.

5.1.3 Deep Foundations for Lighting Masts, Poles and Bus Duct Support Structures Based on the information provided by the client, we understand drilled shaft foundations will be used for lighting masts, lighting poles and bus duct structures near substation building. Lighting masts and Lighting Poles are approximately 65 feet and 30 feet tall respectively. Axial loads, lateral loads and moments at the top of foundation are provided to us by the structural engineer.

This section provides recommendations for design and construction of drilled straight shafts.

Loads Considered:

Loading information and minimum size of the shaft (36-inch diameter) were furnished to us by the structural engineer as described below. Based on information furnished to us, reinforcement for the drilled shafts is assumed as 16 bars #7 type, equally spaced. Actual reinforcement required should be revised based on the maximum bending moment to be resisted by the foundation:

The table below describes axial loads, lateral loads and moments considered for the analysis of drilled shafts;

Axial Load (Kips) Lateral Load at Shaft

Head (Kips)* Moment at Pile Head

(Kip-Ft)* Lighting Mast (65’ tall) 1.92 2.30 60 Light Poles (30’ tall) 0.5 0.5 8.0 Bus Duct Poles 0.8 0.7 8.1

*Lateral Loads are considered as Cyclic.

Foundation Type:

Drilled Straight Shafts are assumed to be installed with Steel Casing, to be removed after pouring concrete. A Pile cap is not assumed and hence no load will be supported by the Pile Cap.

Foundation Properties:

Modulus of Elasticity of Concrete: 3.0 X 106 PSI Density of Concrete: 150 PCF

Based on the subgrade soils encountered, friction angle between concrete footings and site soils for estimating the sliding resistance and lateral stability may be considered equal to 28 degrees.

Reinforcement is assumed at 16 bars of #7 type equally spaced. Preferred size of size of drilled shafts for lighting masts, poles and bus ducts was provided to us by the structural engineer as 36-inch diameter, 21-inches diameter and 30-inch diameter respectively.

Soil Properties (based on borings 8A2S-082 and 8A2S-083):

Groundwater level is assumed at the surface for the analyses (submerged conditions). Modulus of subgrade reaction is estimated based on subsurface soils encountered in test borings 8A2S-082 and 8A2S-083. Resistance to lateral loads within the top 5 feet of soil is significantly discounted due to potential effects of disturbance during construction, variability within the site and weathering affects.

a) From ground surface to 5 feet Unit Weight: 125 PCF

Submerged Unit Weight: 62.2 PCF Angle of Shearing Resistance: 25 degrees Modulus of Subgrade Reaction: 10 PCI

b) From 5 feet to 41.5 feet (bottom of boring depth ) Unit Weight: 125 PCF

Submerged Unit Weight: 62.2 PCF Angle of Shearing Resistance: 32 degrees Modulus of Subgrade Reaction: 60 PCI

Boundary Conditions:

Pile head is considered free to rotate under the lateral load and moments. About 18 inches of the shaft is assumed to be free standing above the ground surface. All the given loads are assumed to be acting at Pile top.

Software and Model:

ALLPILE software (developed by Civil Tech) which is based on FHWA’s COM624P Model is utilized for performing lateral loaded analysis of drilled shafts. Results are also compared with LPILE software (developed by ENSOFT, Inc.) for selected cases to ensure minimizing the errors in modeling.

Lateral load analyses were performed on drilled shafts of different lengths to determine depth of fixity and corresponding values for maximum allowable moment in the shaft, allowable deflection and stresses. Piles/shafts are modeled as beams with elements of elastic behavior whereas soil resistance is modeled as non-linear discrete springs with specific load (pressure) vs. deflection curves. The load deflection curves of soil are determined as a function of modulus of subgrade reaction of subsurface soil deposits. The results of the analyses are summarized below:

Lighting Masts:

Depth* of Shaft (Ft)

Diameter (inches)

Max. Moment (Kip-feet)

Top Deflection (inches)

Bottom Deflection (Inches)

Top Slope

Maximum Stress

(PSI)

15 36 70.6 0.25 -0.08 -0.0030 187 20 36 73.5 0.10 -0.02 -0.0009 194 25 36 74.3 0.08 -0.01 -0.0007 197 30 36 74.6 0.08 -0.001 -0.0007 197

*Includes 1.5 feet above the ground surface

Lighting Poles:

Depth of Shaft (Ft)

Diameter (inches)

Maximum Moment (Kip-feet)

Top Deflection (inches)

Bottom Deflection (Inches)

Top Slope

Maximum Stress

(PSI)

10 21 9.50 0.30 -0.060 -0.0032 127 15 21 10.2 0.10 -0.009 -0.0008 138 20 21 10.6 0.05 -0.001 -0.0007 141

Bus Ducts:

Depth of Shaft (Ft)

Diameter (inches)

Maximum Moment (Kip-feet)

Top Deflection (inches)

Bottom Deflection (Inches)

Top Slope

Maximum Stress

(PSI)

10 30 10.3 0.26 -0.056 -0.0032 47.6 15 30 11.8 0.05 -0.012 -0.0004 54.7 20 30 12.5 0.03 -0.004 -0.0003 57.6

Recommendations:

Based on an allowable deflection of 0.1 inches at the top of shaft, the minimum depth of drilled shafts required for lighting masts, lighting poles and bus ducts are summarized below:

Length (Ft) Diameter (inches) Lighting Mast (65’ tall) 25 36 Light Poles (30’ tall) 15 21 Bus Duct Poles 15 30

5.1.4 Construction Specifications for Drilled Shafts:

We recommend the guidelines for the construction of drilled shaft foundations be based on TXDOT 2004 “Standards Specifications for Construction and Maintenance of Highways, Streets, and Bridges”, Item 416, “Drilled Shaft Foundations” for facilities at this project.

Based on test borings 8A2S-082 and 8A2S-083, the subsurface soils encountered at this site are essentially granular in nature (dense to very dense silty sands, poorly graded silts and thin layers of clayey sands) which will render the drilled shaft excavations unstable. The side walls of open excavations may cave-in due to lack of cohesion even in dry conditions. It is recommended that steel casing and or Bentonite slurry be used to keep the excavations open, from caving in or sloughing to facilitate construction of foundations.

For drilled shaft construction, concrete should be placed using a tremie to displace the lower density slurry. Though groundwater is not encountered during field investigation, the contractor should verify the actual groundwater level, if any, at the time of construction. If groundwater is encountered, Bentonite slurry head should be maintained higher than the groundwater head at the substation facility during construction. Care must be taken to ensure the tremie is placed and maintained at the bottom of the excavation until a height of 5 feet of concrete has been poured in the drilled shaft excavation. As additional concrete is added in the drilled shaft excavation, tremie should be maintained about 5 feet below the top of the concrete surface during the pour.

New drilled shafts should not be excavated within a clear spacing of 6 shaft diameters of open shaft excavations or one in which concrete has been placed in the preceding 4 days. Each drilled shaft excavation should be inspected by a qualified owner’ representative to ensure that 1) the excavation is prepared to the specified dimensions at the recommended depth and formation 2) excessive soil cuttings and any soft compressible materials were removed from the bottom of the excavation.

Placement of concrete should be accomplished as soon as possible after excavation to reduce the changes in state of stress and possible sloughing of foundation soils. Drilled shaft excavations should not be left open over night or poured without the prior approval of the owner’s representative.

5.2 STRUCTURAL FILL AND SUBGRADE PREPARATION

In general, site preparation should consist of removing any existing foundations, paved areas, grass, tree roots, any deleterious materials and stripping organic top soils. The top 3 feet of existing fill soils should be excavated, stock piled on the site, perform proof rolling of exposed sub grade to detect local weak areas. Exposed local weak areas should be over excavated to firm soil, processed, and re-compacted in loose lifts of approximately eight-inch thick. Each lift should be compacted to a minimum of 95% standard proctor density (ASTM D 1557) at moisture content within 3% of optimum.

If existing on-site soils or stock piled soils meet requirements for select fill, it could be reclaimed and re-compacted in loose lifts of approximately eight-inch thick as explained above. On-site soils, which do not meet the select fill requirements, could be either chemically treated, to bring them within the allowable specifications or replaced with select fill materials. The exact amount of chemical treatment shall be determined after performing necessary laboratory tests on representative samples obtained from the affected site area.

Select, structural fill if utilized should be with liquid limit less than 40 and plasticity index (PI) between 7 and 20. This fill should be placed in loose lifts of approximately eight-inches in thickness and compacted to a minimum of 95% standard proctor density (ASTM D 698) at moisture content within 3% of optimum.

All foundation preparation operations including excavation, proof rolling, select fill placement and compaction should be performed under the supervision of a Geotechnical Engineer or an experienced soils technician under the supervision of a Geotechnical Engineer, until the required foundation level is reached.

If the fill placement and compaction operations had to be stopped before the final level is reached, proper care should be taken to protect the compacted surface from getting saturated and softened by covering it with a PVC sheet. Any surface water runoff should be directed away from the compaction area and dewatered immediately and should be kept on throughout this operation.

If the compacted layer gets wet and saturated, the top few inches of soil may be scrapped and allowed to dry before placing the next lift or until dry soils are encountered as directed by the Geotechnical Engineer. Under no circumstances, should any compaction operation or fill placement be allowed on wet soils.

5.3 Excavation

Excavation operations should be conducted in accordance with the Code of Federal Regulations and OSHA guidelines. It is the responsibility of the contractor to design safe excavation plans before personnel enters any open excavation 5 ft. or deeper.

5.4 Pavement Recommendations

This section presents the options for design and construction Rigid and or Flexible Pavements for the proposed Industrial Complex project. Recommendations for Pavement design are based on 1993 AASHTO Guide for Design of Pavement Structures. Software known as WinPAS (American Concrete Pavement Association) has been utilized for the purpose.

The traffic loads data considered include 50% 18 wheelers, 50% UPS/FedEx Delivery Trucks (with a small number of POVs with about 30 each per vehicle per day per site (6 sites), resulting in a total of 180 trips for each vehicle type per day. Information is also available for a fire truck to be used on the site with a total weight of 80,800 lbs with Axle Loads of 22,800 lbs (front) and 58,000 lbs (rear).

Based on the information provided to us as above, the traffic load in terms of number of 18 Kip Equivalent Static Axial Loads (ESAL) is estimated for input into the Pavement Design Software.

Recommendations are provided for both Heavy Traffic Volume areas (Roadways) and lightly loaded areas such as Parking Lots.

Our recommendations are based on a 20-year life span and the following street classifications and Equivalent Single-Axle Load (ESAL) values.

Street Classification and ESAL Data Street Classification 18-Kip ESALs

Heavy Traffic Areas 1000,000 Parking Lot POV 100,000

In the event that actual traffic conditions vary from those indicated herein, Archana USA, Inc.

should be notified immediately so that our recommendations can be revised. Following design input values are considered:

5.4.1 Rigid Pavement Parameters:

i) Reliability: 90%

ii) Overall Deviation: 0.35

iii) Modulus of Rupture: 550 PSI

iv) Modulus of Elasticity: 3,700,000 PSI

v) Load Transfer: 3.2

vi) Modulus of Subgrade Reaction: 31 psi/inch

vii) Drainage Coefficient: 1.00

viii) Initial Serviceability: 4.5

ix) Terminal Serviceability: 2.0

x) Resilient Modulus of sub grade: 4,500 psi

xi) Resilient Modulus of sub base: 30,000 psi

xii) Sub base Thickness: 8-inch

xiii) Depth to Rigid Foundation: 0.00 feet

xiv) Loss of Support Value: 2.0

Rigid pavement structures should consist of Portland cement concrete with steel reinforcement.

We recommend the following minimum pavement sections.

5.4.2 Rigid Pavement Recommendations:

Type of Pavement Structure

PCC

(in.)

Compacted Subgrade (in.)

Roadways 8 12 Parking Lot POV 6 12

Additional Design Consideration for Tank Loads:

Pavement design has been checked for potential tank loading from government vehicles in certain areas of parking lots and drive ways for allowable stresses and bearing capacity of subgrade soils. The tank traffic evaluated considered for evaluation include the following;

i) M1SEPV2 Tank (2 treads)

ii) M88A2 Tank (2 treads)

iii) M109A6 Tank (2 treads)

iv) M992 Tank (2 treads)

v) M113 Tank (2 treads)

vi) M2A3 Bradley Tank (2 treads)

vii) M104 Wolverine Tank (2 treads)

viii) M9 ACE Tank (2 treads)

ix) AVLB Tank (2 treads)

x) Fire Truck (22,800 lbs single axle 2 wheels

58,000 lbs tandem axle 4 wheels)

All Tanks are considered with Tridem (3) axles with two(2) tracks for estimating 18 Kip ESALs .

Load equivalent factors are individually computed for the each of the tanks based on which 18 Kip Equivalent Static Axle Loads (ESAL) were estimated by assuming that all the tanks will be present at one time in any parking area. Based on the above assumptions, the estimated ESALs for the tank loadings are estimated to be 548,300 for 20 years and 818,000 for 30 years Life Span.

Since the assumed ESALs for the pavement design is 1000,000 ESALs for 20 years life span which exceeds the above estimated ESAL values for the tank loadings provided, we believe the previously based design is adequate for the new tank loadings also.

The dimensions of tracks are assumed to vary from 17.5 feet to 19.5 feet and about 2 feet wide which are used to estimate stresses under the paving for safety against bearing capacity failure.

5.4.3 Rigid Pavement Construction Guidelines

Upon completion of placement and finishing (e.g., broom), an approved curing compound should be applied. The application of this liquid membrane will help reduce shrinkage cracking.

Reinforcement should not extend beyond expansion joints.

Details for Pavement Design and Reinforcement Calculations for Pavements are provided for various thicknesses with reference to slab length and width in Appendix-B.

At the direction of the structural engineer, rigid pavement joints may be included in the design and construction of Portland cement concrete pavements. The installation of joints will help in controlling the magnitude and location of cracks. Expansion, control, and sawed joints (to form square sections) should be planned in accordance with ACI 302.69 (which recommends a maximum of 30 times the pavement thickness).

The slab width-to-length ratio should not exceed 1.25. Additionally, we recommend that the maximum joint spacing be 15 ft. transversal and 15 ft. longitudinal. The depth of the control joints should be sawed (or formed) to a depth of at least ¼ the concrete slab thickness and should have a width ranging between ¼-in. and 1/8-in. The saw-cut operations should take place within 8 hours upon concrete placement and as soon as concrete will not ravel. After cleaning the saw-cut joints with high-pressure air stream, these should be sealed with an elastomeric sealant that meets TXDOT Item 433, Class 4 or 5 requirements.

To transfer loads between concrete construction joints, No. 4 bars (18 in. long) should be placed parallel to traffic at 30-in. on center. The placement at control joints of dowel bars, which should be clean, free of deleterious matter, and lubricated, is recommended. These dowels (18-in. in length) should be placed 12-in. on center and should have a 1/8 -in. diameter per inch of pavement thickness.

5.5 FLEXIBLE…