Amendment_No._2_-_Convent_-NTX00007_-_Div_01_Specifications.pdf

05.23.14

U.S. GENERAL SERVICES ADMINISTRATION

GREATER SOUTHWEST REGION

0B Expansion and Modernization of the Convent Avenue

1 BUnited States Land Port of Entry Laredo, Texas

GSA Project #NTX00007

2B100% Construction Documents

3BMay 23, 2014

Prepared by: RICHTER ARCHITECTS

201 South Upper Broadway

Corpus Christi, Texas 78401

Telephone: 361-882-1288

SENSITIVE BUT UNCLASSIFIED (SBU)

PROPERTY OF THE UNITED STATES GOVERNMENT

COPYING, DISSEMINATION, OR DISTRIBUTION OF THIS DOCUMENT TO UNAUTHORIZED

RECIPIENTS IS PROHIBITED

Do not remove this notice. Properly destroy or return documents when no longer needed.

TABLE OF CONTENTS 00 01 10 - 1

Expansion and Modernization of the (Laredo) Convent Avenue Project No. NTX00007

United States Land Port of Entry

DIVISION – SECTION TITLE PAGES

DIVISION 00 - PROCUREMENT AND CONTRACTING REQUIREMENTS

00 01 07 - SEALS PAGE

00 01 10 - TABLE OF CONTENTS

00 01 15 - LIST OF DRAWINGS

00 31 32.13 - GEOTECHNICAL ENGINEERING REPORT (SUBSURFACE DRILLING & SAMPLING INFORMATION ). 53

DIVISION 01 - GENERAL REQUIREMENTS

011100-SUMMARY

01 14 00 - WORK RESTRICTIONS............................................(Refer Combined Specification Sections)

012200-UNITPRICES

01 23 00 - OPTIONS (ALTERNATES)

01 29 00 - PAY PROCEDURES .................................................(Refer Combined Specification Sections)

01 30 00 - ELECTRONIC PROJECT MANAGEMENT AND COORDINATION .(Refer Combined Specification Sections)

01 31 00 - PROJECT MANAGEMENT AND COORDINATION ..........(Refer Combined Specification Sections)

01 32 00 - CONSTRUCTION PROGRESS DOCUMENTATION ..........(Refer Combined Specification Sections)

01 32 16 - CRITICAL PATH METHOD SCHEDULING ....................(Refer Combined Specification Sections)

01 32 20 - PHOTOGRAPHIC DOCUMENTATION .........................(Refer Combined Specification Sections)

01 33 00 - SUBMITTAL PROCEDURES.......................................(Refer Combined Specification Sections)

01 33 29 - SUSTAINABLE DESIGN REPORTING

01 35 29 - SAFETY AND HEALTH ............................................(Refer Combined Specification Sections)

01 35 53 - SECURITY PROCEDURES.........................................(Refer Combined Specification Sections)

01 35 91 - HISTORIC TREATMENT PROCEDURES

01 42 19 - REFERENCE STANDARDS AND DEFINITIONS

01 43 00 - QUALITY ASSURANCE AND CONTROL .......................(Refer Combined Specification Sections)

01 45 29 - STRUCTURAL TESTING & INSPECTIONS

01 50 00 - TEMPORARY FACILITIES AND CONTROLS..................(Refer Combined Specification Sections)

01 60 00 - PRODUCT REQUIREMENTS......................................(Refer Combined Specification Sections)

01 70 00 - EXECUTION REQUIREMENTS ...................................(Refer Combined Specification Sections)

01 71 23 - FIELD ENGINEERING

01 74 19 - CONSTRUCTION WASTE MANAGEMENT AND DISPOSAL

01 77 00 - CLOSEOUT PROCEDURES .......................................(Refer Combined Specification Sections)

01 78 22 - OPERATION AND MAINTENANCE DOCUMENTATION ....(Refer Combined Specification Sections)

01 78 36 - WARRANTIES....................................................... (Refer Combined Specification Sections)

01 78 39 - PROJECT RECORD DOCUMENTS...............................(Refer Combined Specification Sections)

01 79 00 - DEMONSTRATION AND TRAINING........................... (Refer Combined Specification Sections)

01 81 13 - SUSTAINABLE DESIGN REQUIREMENTS - LEED® FOR NEW CONSTRUCTION & MAJOR RENOVATIONS 8

LEED® 2009 NC Checklist

01 91 00 - COMMISSIONING REQUIREMENTS

A. Architect:

1. David Richter, FAIA

Richter Architects 201

S. Upper Broadway

Corpus Christi, Texas 78403

2. Texas Architectural Registration #7113

3. Responsible for Divisions 1-33 Sections except where indicated as prepared by other design professionals of record.

12/31/2013

Expansion and Modernization of the (Laredo) Convent Avenue Project No. NTX00007

United States Land Port of Entry

SECTION 00 01 07 - SEALS PAGE

1.1 DESIGN PROFESSIONALS OF RECORD

B. Civil Engineer:

1. Jon D. Coenen, III, P.E.

Walter P. Moore & Associates, Inc. 1301 McKinney, Suite 1100

Houston, Texas 77010 Texas

Firm Registration #1856

2. Texas P.E. Serial No. 103372

3. Responsible for Divisions 311100-

312500, 313213.16-314133, 320116-321313, 321723321723.17, 323113, 329213 Sections except where indicated as prepared by other design professionals of record.

C. Landscape Architect:

1. Doug Wade, Landscape Architect 537

Chamberlain Street

Corpus Christi, Texas 78404-2602

2. Texas Landscape Architect Registration #097

3. Responsible for Divisions 328400-329300 Sections except where indicated as prepared by other design professionals of record.

SEALS PAGE 00 01 07-1

SENSITIVE BUT UNCLASSIFIED (SBU), PROPERTY OF THE UNITED STATES GOVERNMENT FOR OFFICIAL USE ONLY. Do not remove this notice. Properly destroy or return documents when no longer needed.

United States Land Port of Entry

D. Structural Engineer:

1. Brent Wenger, P.E.

Walter P. Moore & Associates, Inc.

1301 McKinney, Suite 1100

Houston, Texas 77010

Texas Firm Registration #1856

2. Texas P.E. Serial No. 92565

3. Responsible for Divisions 014529, 033000, 033100, 034100, 042213, 051200, 053123, 053133, 054100, 312300, 316329 Sections except where indicated as prepared by other design professionals of record.

E. Fire-Protection Engineer:

1. Jack Poole, P.E.

POOLE FIRE PROTECTION

19910 West 161 Street

Olathe, Kansas

2. Texas P.E. Serial No. 91563

3. Responsible for Divisions 211313 & 283111 Sections except where indicated as prepared by other design professionals of record.

F. HVAC/Plumbing Engineer:

1. Ali Hami, P.E.

GOETTING & ASSOCIATES, INC.

12042 Blanco Road, Suite 200

San Antonio, Texas 78216-2440

Texas Firm Registration #903

2. Texas P.E. Serial No. 67441

3. Responsible for Divisions

220500-238216 Sections except where indicated as prepared by other design professionals of record.

SEALS PAGE 00 01 07-2

SENSITIVE BUT UNCLASSIFIED (SBU), PROPERTY OF THE UNITED STATES GOVERNMENT FOR OFFICIAL USE ONLY. Do not remove this notice. Properly destroy or return documents when no longer needed.

United States Land Port of Entry

G. Electrical Engineer:

1. Jesus Garcia, P.E.

GOETTING & ASSOCIATES, INC.

12042 Blanco Road, Suite 200 San

Antonio, Texas 78216-2440 Texas

Firm Registration #903

2. Texas P.E. Serial No. 97333

3. Responsible for Divisions

260100-265600 Sections except where indicated as prepared by other design professionals of record.

H. Security:

1. Charles LeBlanc, P.E.

KROLL ADVISORY SOLUTIONS

1025 Main Street

Bastrop, Texas 78602

Texas Firm Registration #F-6147

2. Texas P.E. Serial No. 111538

3. Responsible for Divisions 281300 & 282300 Sections except where indicated as prepared by other design professionals of record.

END OF SECTION 00 01 07

SEALS PAGE 00 01 07-3

SENSITIVE BUT UNCLASSIFIED (SBU), PROPERTY OF THE UNITED STATES GOVERNMENT FOR OFFICIAL USE ONLY. Do not remove this notice. Properly destroy or return documents when no longer needed.

Geotechnical Engineering Report U. S. Border Station Renovation

International Bridge No. 1

Laredo, Texas

July 1, 2011

Terracon Project No. 89115008

Prepared for:

The Louis Berger Group, Inc.

Exton, PA

Prepared by:

Terracon Consultants, Inc.

Laredo, Texas

N.JA,vcoL(c )1.6.•

Edgar A. Munoz, P.E.

Department Manager

Sincerely, Terracon Consult ts, Inc.

(Firm Registration: F3272)

Martin Re , E.I.T.

Project M ager

MR/EAM 1M inc — 89115008

Copies To: Addressee: (3) Bound & (1) Electronic lrerracon July 1,2011

The Louis Berger Group, Inc.

350 Eagleview Boulevard

Exton, Pennsylvania 19341

Attn: Mr. Joseph R. Dietrich, P.E.

P: [610] 280 4049

F: [610] 363 5390

E: jdietrichlouisberoer.com

Re: Geotechnical Engineering Report

U.S. Border Station Renovation

International Bridge No. 1

Laredo, Texas

Terracon Project No. 89115008

Dear Mr. Dietrich:

Terracon Consultants, Inc. (Terracon) is pleased to submit our Geotechnical Engineering Report for the above referenced project. We trust that this report is responsive to your project needs. Please contact us if you have any questions or if we can be of further assistance.

We appreciate this opportunity to be of service to you on this phase of the project. We look forward to continuing our involvement in the project by providing field observation and materials testing services during construction. In order for us to effectively provide these services, we will need a complete set of plans and specifications for our use. In addition, we should be invited to the preconstruction meeting to address any construction issues before site work begins.

Geotechnical • Environmental • Construction Materials • Facilities

Terracon Consultants, Inc. 615 Gale Street, Building B, Laredo, Texas 78041

P [9561729-1100 F (956) 791-1071 Texas Professional Engineers No. F-3272 terracon.com

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U.S. Border Station Renovation ■ Laredo, Texas July 1, 2011 ■ Terracon Project No. 89115008

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 Site Geology

3.2 Typical Profile

3.3 Groundwater

4.0 RECOMMENDATIONS FOR DESIGN AND CONSTRUCTION

4.1 Fill Discussion

4.2 Special Methane Gas Monitoring Requirements

4.3 Geotechnical Considerations

4.4 Earthwork

4.4.1 General Site Preparation

4.4.2 Structure Pad Preparation

4.4.3 Fill Materials and Placement

4.4.4 Compaction Requirements

4.4.5 Grading and Drainage

4.4.6 Construction Considerations

4.4.7 Differential Movement Between Structures

4..5 Foundations

4.5.1 Drilled Piers

4.5.1.1 Straight-Sided Piers

4.5.2 Drilled Pier Foundation Installation

4.5.3 Shallow Foundations

4.5.3.1 Spread Footing Design Recommendations

4.5.3.2 Slab-on-Grade Foundation Design Recommendations

4.5.3.3 Shallow Foundations Construction Considerations

4.5.4 Pavement Slab

4.5.5 Foundation Construction Observation

4.6 Retention Systems

4.6.1 Lateral Earth Pressures

4.7 Seismic Considerations

4.8 Pavements

4.8.1 Design Recommendations

4.8.2 Pavement Section Materials

4.8.3 Pavement Joints and Reinforcement

4.8.4 Pavement Reuse

5.0 GENERAL COMMENTS

U.S. Border Station Renovation ■ Laredo, Texas July 1, 2011 ■ Terracon Project No. 89115008

TABLES

Table 1 Lateral and Axial Design Parameters

Table 2 Slab Foundation Design Parameters

Table 3 Caliche Base Course Requirements

APPENDIX A – FIELD EXPLORATION

Exhibit A-1 Field Exploration Description Exhibit A-2 Site Location Plan Exhibit A-3 Bore Location Plan

Exhibits A-4 to A-8 Boring Logs

APPENDIX B – LABORATORY TESTING

Exhibit B-1 Laboratory Testing

APPENDIX C – SUPPORTING DOCUMENTS

Exhibit C-1 General Notes

Exhibit C-2 Unified Soil Classification System

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U.S. Border Station Renovation ■ Laredo, Texas July 1, 2011 ■ Terracon Project No. 89115008

EXECUTIVE SUMMARY

This geotechnical investigation has been performed for the proposed U.S. Border Station

Renovation and related structures to be located at International Bridge No. 1, near the intersection of Convent Avenue and Water Street in Laredo, Texas. A total of 5 borings were drilled to depths of approximately 50 to 100 feet below existing grade within the proposed development. Groundwater was encountered during and after completion of the borings.

Groundwater conditions are discussed in the report.

Based on the information obtained from our subsurface exploration, the site can be developed for the proposed project. The following geotechnical considerations were identified:

A deep foundation (drilled pier) system may be considered to support the canopy structure.

Shallow foundation system may be used to support small inspection booth structures.

Assuming proper site and subgrade preparations total and differential settlement should be within anticipated client/owner specifications.

All pavements under the canopy are proposed to be removed and replaced after minor grading adjustments. It is our understanding that new pavement surface will consist of concrete or concrete pavers.

Based on the 2009 International Building Code, Tables 1613.5.6 (1) and 1613.5.6 (2), IBC seismic site classification for this site is C.

This summary should be used in conjunction with the entire report for design purposes. It should be recognized that 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.

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GEOTECHNICAL ENGINEERING REPORT

U.S. BORDER STATION RENOVATION

INTERNATIONAL BRIDGE NO.: 1

LAREDO, TEXAS

TERRACON PROJECT NO.: 89115008

JULY 1, 2011

1.0 INTRODUCTION

Terracon Consultants, Inc. (Terracon) is pleased to submit our Geotechnical Engineering Report for the above referenced project. This project was authorized by Ms. Cosema (Connie)

Crawford, P.E. with Louis Berger Group, Inc. through signature of “Subcontract Agreement” on

February 16, 2011. The scope of services for this project is outlined in Proposal No

P89100070R2 dated January 20, 2011.

The purpose of this report is to describe the subsurface conditions observed at the borings drilled for this study, analyze and evaluate the test data, and provide recommendations with respect to:

subsurface soil conditions • groundwater conditions earthwork • foundation design and construction seismic considerations • floor slab design and construction pavement design and construction • lateral earth pressures

Location

Existing topography

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Geotechnical Engineering Report U.S. Border Station Renovation ■ Laredo, Texas July 1, 2011 ■ Terracon Project No. 89115008

2.0 PROJECT INFORMATION

2.1 Project Description

Item Description

Site layout See Exhibits A-2 & A-3, Site Location Plan & Bore Location Plan

Structures

Based on information provided to us, the existing building is to remain with the exception of exterior and interior upgrades. A small extension of the existing building will occur under the canopy to provide for a new guard head house.

The existing canopy is to be removed and replaced with a new canopy structure. Under the canopy area, new guard booths are proposed along with supporting utility infrastructure.

The existing retaining wall located at the north end of the site is to be removed and replaced based on the new grading and site layout. A new pedestrian walkway will be constructed within the alley on the eastern side of the site. At this point, it is assumed the walkway will be concrete slabs supported with retaining walls as necessary for grade transitions. A small plaza area is proposed at the northeastern corner of the site.

Construction Type

The canopy structure will consist of a pre-engineered steel framed structure, supported by drilled pier foundation system. The new guard booths will consist of pre-engineered metal with glass front and sides and may be supported by shallow slab-on-grade foundation system.

Finished Floor and

Grade Elevations

Minor grading adjustments are anticipated. The FFE were not available at the time of this report was prepared.

Maximum Loads Unknown at this time. However, the canopy loads will be similar to the existing; there are no planned structures above the canopy.

Pavements

Pavements and curbing under the canopy are proposed to be removed and replaced after minor grading adjustments. It is our understanding that new pavement surface will consist of concrete or concrete pavers.

2.2 Site Location and Description

Item Description

This project will be located at International Bridge No. 1, near the intersection of Convent Avenue and Water Street in Laredo, Texas.

Existing improvements Existing U.S. Border Station facilities.

Current ground cover Rigid and asphalt pavements.

Based on topographic information provided to us by Civil Engineering Consultants, Inc. (CEC) the site is gently sloping downward from north to south side of the proposed project site. The difference in elevation across the area is approximately 9 feet. Elevations ranged from 395 feet to 404 feet.

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U.S. Border Station Renovation ■ Laredo, Texas July 1, 2011 ■ Terracon Project No. 89115008

3.0 SUBSURFACE CONDITIONS

3.1 Site Geology

The Geologic Atlas of Texas, Laredo Sheet, 1976, published by the University of Texas at Austin, Bureau of Economic Geology, has mapped the Fluviatile Terrace Deposits of the Pleistocene geologic age in the vicinity of the site. The Fluviatile Terrace Deposits consists of gravel, sand, silt and clay; composed of materials similar to those present in contiguous alluvium.

3.2 Typical Profile

Based on the results of the borings, subsurface conditions on the project site can be generalized as follows:

Description Approximate Depth of Stratum (feet) Material Encountered Consistency/Density

---- 0 to 1 Pavement Section (asphalt, concrete and base)

Stratum IA 1 to 28 Fill: SANDY SILTY CLAY 1 ; light brown encountered only in boring No. B-1 Medium Stiff to Hard

Stratum I 1 to 23 SANDY SILTY CLAY 1 ; light brown Soft to Hard

Stratum II 13 to 40 SILTY SAND 2 ; light brown Medium Dense to Very

Dense

Stratum III 23 to 100 CLAYSTONE 3 ; bluish gray Hard

1 The Fill: SANDY SILTY CLAY (CL-ML) and SANDY SILTY CLAY (CL-ML) materials could undergo low volumetric changes (shrink/swell) should they experience changes in their in-place moisture content.

2 The SILTY SAND (SM) materials encountered are not expected to experience volumetric changes (shrink/swell) with fluctuations in moisture content. These materials are considered volumetrically stable with regards to change in moisture content due to their granular nature.

3 The CLAYSTONE is expected to undergo moderate volumetric changes with fluctuations in its moisture content. However, depth at which this stratum was encountered will lessen its volumetric changes.

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 of the borings can be found on the boring logs in Appendix A of this report.

3.3 Groundwater

The borings were drilled using dry augered drilling techniques. The boreholes were backfilled with sand and the pavement was patched with asphalt cold mix and concrete ready mix upon

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U.S. Border Station Renovation ■ Laredo, Texas July 1, 2011 ■ Terracon Project No. 89115008 completion. The short-term field observations simply do not permit an accurate evaluation of the subsurface water levels at this location. Subsurface water levels are influenced by seasonal and climatic conditions, which can and will change. If an accurate determination of the groundwater table is necessary, long term observations in piezometers or observation wells sealed from the influence of surface water are often required to define groundwater levels in materials of this type. The foundation contractor should check the subsurface water conditions just prior to foundation excavation activities.

Groundwater measurements are considered approximate and are short-term, since the borings are open for a short time period. On a long-term basis, the groundwater levels will vary and may be present at shallower depths. The water levels observed in the boreholes are noted on the attached boring logs presented in Appendix A of this report, and are summarized below:

Boring No.

Groundwater During Drilling Groundwater After Drilling

B-1 37.5 357.5 32.5 362.5

B-2 33.0 364.0 30.0 367.0

B-3 22.0 376.0 20.0 378.0

B-4 23.0 378.0 22.0 379.0

B-5 29.0 367.0 28.0 368.0

1 Depths measured from existing ground surface at time of drilling operations. Subsurface water levels have been rounded to the nearest one-half (1/2) foot. The elevations were estimated from the topographic information provided to us.

4.0 RECOMMENDATIONS FOR DESIGN AND CONSTRUCTION.

The following recommendations are based upon the data obtained from our field and laboratory programs, project information provided to us and on our experience with similar subsurface and site conditions.

4.1 Fill Discussion

Fill was observed in boring No. B-1 and extended to a depth of about 30 feet. The fill soils are generally composed of Sandy Silty Clay (CL-ML) and foreign matter (concrete and bricks debris).

No records or documentation were available regarding the placement or compaction of these soils. The boring indicates the fill is non uniform and that the competency of this layer is variable and its horizontal extent is unknown. In addition, the area of the project is located within an old landfill in downtown Laredo.

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U.S. Border Station Renovation ■ Laredo, Texas July 1, 2011 ■ Terracon Project No. 89115008

The upper subsoils exhibit low potential for experiencing shrink-swell during fluctuation in its moisture content. Depending on the loads imposed by the various structures, the fill body may impact “design” due to the potential for settlement or consolidation of this material when subjected to loading. Foundations bearing below the fill body and into the natural soils would reduce differential settlements.

Based on our field test results and observations, we concluded that any fill material containing any foreign matter within 3 feet of the bottom of the foundation must be removed to provide adequate bearing support for any shallow foundation and grade supported floor slab and structures.

4.2 Special Methane Gas Monitoring Requirements

Based on our experience with adjacent projects in the area of this project and the presence of an old landfill in the vicinity, Terracon utilized methane gas level monitoring during our drilling operations of the 5 borings. The use of methane monitoring devices was part of our safety procedure.

Based on our monitoring of the bore hole, methane gas levels were recorded. The levels readings were between no detection to positive at various locations, therefore the contractor should assign a competent individual to detect methane gas zones and levels during construction. If this individual determines that air contaminants may present a danger to life at any time, the contractor must immediately take all necessary precautions. In performing methane gas monitoring duties, the contractor must take into consideration the location of the jobsite; the geology of the site, including soil type and permeability; the history of the site and the construction operation; and work practices at the jobsite (use of diesel engines, explosives, and fuel gas; hot work, welding, and cutting).

4.3 Geotechnical Considerations

We understand that the structural loads for the proposed canopy will be supported by a drilled pier foundation system. Small structures such as guard booth may be supported by shallow foundation system. The desired foundation system may be used at this site provided the structure foundations are designed and constructed as recommended in this report.

The foundations being considered to provide support for the planned structure must satisfy two completely independent engineering criteria with respect to the subsurface conditions encountered at the site. One criterion is the foundation system must be designed with an appropriate factor of safety to reduce the possibility of soil failure when subjected to axial and lateral load conditions. The other criterion is foundation movements, whether vertical, horizontal or rotational, must be within allowable limits of the subsurface materials and within operational limits of the foundation and structure.

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U.S. Border Station Renovation ■ Laredo, Texas July 1, 2011 ■ Terracon Project No. 89115008

For canopy structures, the foundations will need to be designed to resist relatively high tensile loads due to its height and the imposed forces from wind loading. Generally, three load cases are applied to these types of structures; axial compressive loading, axial uplift (tensile) loading and lateral loading. Canopy foundations generally experience high uplift axial loads that typically control the foundation design. Axial compressive and lateral loading of these foundation types is often relatively low and seldom controls the foundation design. However, the foundations should always be analyzed for the three load cases to make certain of the controlling load case. Recommendations will be discussed in the foundation section of this report.

Based on our findings, the near-surface clayey soils at this site generally exhibit a low potential to experience significant volume changes (expansion and contraction) as the result of moisture fluctuation. Based on the information developed from our field and laboratory programs and on method TEX-124-E in the Texas Department of Transportation (TxDOT) Manual of Testing

Procedures, we estimate that the subgrade soils at this site exhibit a Potential Vertical Rise

(PVR) of less than 1 inch in their present condition. The actual movements could be greater if inadequate drainage, ponded water, and/or other sources of moisture are allowed to infiltrate beneath the structure after construction. Based on the PVR results, expansion and contraction due to expansive soils is not a concern at this site.

4.4 Earthwork

The following presents recommendations for general site preparation, pad 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.

4.4.1 General Site Preparation

Prior to placing any fill, existing pavement (concrete, asphalt and base), foreign matter and any otherwise unsuitable materials should be removed from the construction area. The existing asphalt and base material may be reused. Recommendations to reuse these materials are provided in the “Pavement Reuse” section of this report. The stripped materials consisting of foreign materials (fill) should be wasted from the site or should be stockpiled, cleaned of garbage and placed back in controlled and compacted manner. After stripping, the subgrade should be proof-rolled where possible to aid in locating loose or soft areas. Proof-rolling can be performed with at least 15-ton roller or fully loaded dump truck. Soft, dry and low-density soil should be removed or compacted in place prior to placing fill.

The resulting subgrade in cut areas should be scarified to a depth of 8 inches; moisture conditioned, and compacted to the requirements given in this report. Fill and backfill soils should be placed; moisture conditioned, and compacted as noted in this report. Soils within

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U.S. Border Station Renovation ■ Laredo, Texas July 1, 2011 ■ Terracon Project No. 89115008 structure and pavement areas should not be allowed to dry out or become excessively wet after compaction is completed. Placement and compaction of soil is discussed below:

Structure Areas: Refer to the “Inspection Booths Pad Preparation” section of this report.

General and Common Areas (not requiring structural support): Compact to at least

95 percent of the maximum dry density as evaluated by ASTM D 698 (Standard

Compaction) at compaction moisture contents between -2 and +3 percentage points of optimum moisture content.

4.4.2 Inspection Booths Pad Preparation

The Finished Floor Elevations (FFE) will be at about the same as that for the existing inspection booths. As previously mentioned, the existing PVR at this site is less than 1 inch and it is not a design concern. We have provided a subgrade preparation method that is intended to maintain the magnitude of soil movements beneath grade supported structures at this site to about 1 inch or less. The following recommendations are based on Finished Floor Elevations (FFE) to within

6 inches of existing grade.

Remove the existing pavements or concrete structures from the inspection booth area.

The inspection booth area is defined as the area that extends at least 3 feet beyond the perimeter of the structure, including any flatwork that abuts the structure such as sidewalks. If fill encountered, remove any garbage or foreign material for a depth of 3 feet below the bottom of shallow foundation.

The exposed subgrade in the inspection booth area should be proofrolled with at least a

15-ton roller, or equivalent equipment, to evidence any weak yielding zones. A Terracon geotechnical engineer or his/her representative should be present to observe proofrolling operations.

Over-excavate any confirmed weak yielding zones, both vertically and horizontally, to expose competent soil. The excavated soil can be used to restore grade provided that the material is relatively free and clean of deleterious material or materials exceeding 3 inches in maximum dimension. The soil should be placed in loose lifts of no more than 8 inches; moisture conditioned to between -2 to +3 percentage points of the optimum moisture content and compacted to at least 95 percent of the maximum dry density determined in accordance with ASTM D 698.

After proofrolling and the replacement of weak yielding zones, scarify and moisture condition the top 8 inches of subgrade to between -2 and +3 percentage points of the optimum moisture content. Compact the subgrade to at least 95 percent of the maximum dry density determined in accordance with ASTM D 698.

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U.S. Border Station Renovation ■ Laredo, Texas July 1, 2011 ■ Terracon Project No. 89115008

Select fill or on-site material provided they are clean from all foreign matter should then be placed in the inspection booth areas to achieve the desired final pad elevation. The select fill should be placed in 6 inches compacted lifts. The select fill should be moisture conditioned between -2 and +3 percentage points of optimum moisture content and then compacted to at least 95 percent of the maximum dry density determined in accordance with ASTM D698 (standard compaction). On-site soils “clean” of foreign matter and debris may be used as select fill provided they meet the select fill criteria presented in this report.

4.4.3 Fill Materials and Placement

Subsequent to proofrolling, and just prior to placement of all structural fill, the exposed subgrade within the construction area should be evaluated for moisture and density. If the moisture, density, and/or the requirements do not meet the criteria described in the table below, the subgrade should be scarified to a depth of 8 inches; moisture adjusted and compacted to at least 95 percent of the Standard Effort (ASTM D 698) maximum dry density. Select fill and on-site soils should meet the following criteria.

Fill Type

USCS Classification Acceptable Location for Placement

Granular Select Fill 2 Varies Inspection booth pads, pavements and flatwork.

Select Fill CL or SC

(7≤PI≤20)

Inspection booth pads, pavements and flatwork

On-Site Varies

The on-site soils appear suitable for use as fill within the landscape areas, provided they are free of organics and debris. Additionally, if they meet the criteria for select fill soils, they may be used within the new inspection booth areas.

On-Site Processed

Asphaltic Concrete

Can be milled and processed as necessary to achieve a maximum size of 3 inches. The milled material can be used in the structure pads as granular select fill under the floor slab.

Flowable Fill 3 --- Confined areas.

1 Prior to any filling operations, samples of the proposed borrow and on-site materials should be obtained for laboratory moisture-density testing. The tests will provide a basis for evaluation of fill compaction by in-place density testing. A qualified soil technician should perform sufficient in-place density tests during the filling operations to evaluate that proper levels of compaction, including dry unit weight and moisture content, are being attained.

2 Granular select fill should consist of 2004 TxDOT Item 247, Type A or B, Grade 1 or 2 crushed limestone or gravel base material. Granular select fill can also consist of crushed concrete meeting the criteria specified in the 2004 TxDOT Item 247, Type D, Grade 1 or 2. Plasticity Index should range from

7 to 20. On-site processed asphaltic concrete may be used as granular select fill.

3 Flowable fill should have a 28 day strength between 80 and 150 psi and meet the requirements for

2004 TXDOT Item 401. Although usually more costly, flowable fill does not require placement in lifts or mechanical compaction.

Fill Lift Thickness

Compaction of OnSite Soils;

Compaction of All Select fill;

Moisture Content of All Soils;

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Geotechnical Engineering Report U.S. Border Station Renovation ■ Laredo, Texas July 1, 2011 ■ Terracon Project No. 89115008

4.4.4 Compaction Requirements

Item Description

All fill should be placed in thin, loose lifts not to exceed 8 inches, with compacted thickness of about exceed 6 inches.

95% of the material’s Standard Proctor maximum dry density (ASTM D 698).

95% of the material’s Standard Proctor maximum dry density (ASTM D 698).

The materials should be moisture conditioned between -2 to +3 percentage points of the optimum moisture content.

1 Unless otherwise noted within this report all compaction requirements are provided above.

4.4.5 Grading and Drainage

Positive drainage should be provided during construction and maintained throughout the life of the development. Infiltration of water into utility trenches or foundation excavations should be prevented during construction. Planters and other surface features which could retain water in areas adjacent to the structures should be sealed or eliminated. In areas where sidewalks or paving do not immediately adjoin the structure, we recommend that protective slopes be provided with a minimum grade of approximately 5 percent for at least 10 feet from perimeter structure walls. Backfill against grade beams, exterior walls, and in utility and sprinkler line trenches should be well compacted and free of all construction debris to reduce the possibility of moisture infiltration.

Downspouts, roof drains or scuppers should discharge into splash blocks or extensions when the ground surface beneath such features is not protected by exterior slabs or paving. Sprinkler systems should not be installed within 5 feet of foundation walls. Landscaped irrigation adjacent to the foundation systems should be minimized or eliminated.

4.4.6 Construction Considerations

It is anticipated that excavations for the proposed construction can be accomplished with conventional earthmoving equipment and rock cutting equipment. Based upon the subsurface conditions determined from the geotechnical exploration, subgrade soils exposed during construction are anticipated to be relatively stable. However, the stability of the subgrade may be affected by precipitation, repetitive construction traffic or other factors. If unstable conditions develop, 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.

The individual contractor(s) is responsible for designing and constructing stable, temporary excavations (as required to maintain stability of both the excavation sides and bottom).

Excavations should be sloped or shored in the interest of safety following local and federal regulations, including current OSHA excavation and trench safety standards.

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U.S. Border Station Renovation ■ Laredo, Texas July 1, 2011 ■ Terracon Project No. 89115008

4.4.7 Differential Movement Between Structures

We understand that a small building addition is also planned and Finished Floor Elevation (FFE) is set to match the FFE of the existing building. Differential movement between adjacent foundations is always a concern. Differential movement can be addressed by constructing an expansion joint between the existing structure and new concrete area. Foundation types between the existing and new structures should be similar. At common openings, consideration should be given to limiting differential movement by the use of dowels between the existing and new foundations. Properly installed, the dowels should help limit differential movement (and possible trip hazards) but allow horizontal drying shrinkage of the new slab foundation. While dowelling the 2 foundations will help limit differential movements, hinge cracking should be expected at these doweled locations if differential movements occur.

In addition, excavation for the new foundation should be performed with care, so the foundation for the existing structure will not be disturbed or undermined. In most applications, subsidence of the nearby ground surface cannot be tolerated due to excavation next to the existing building.

Some form of retention system will need to be considered for the below grade excavations which does not allow an unbraced excavation or open cut slopes. These retention systems are generally installed prior to any mass excavation.

Foundation loads for the new structure may add load to the soils supporting the existing structure. This should be considered when sizing the new foundations.

4.5 Foundations

We understand that a drilled pier foundation system will support the structural loads of the proposed canopy. The flat work under the canopy will be grade supported. We also understand that small structures such as guard booth may be constructed at grade with shallow foundation system. In addition below grade walls and retaining walls will be constructed at this site.

Recommendations for these types of foundation systems are provided in the following sections.

4.5.1 Drilled Piers

Drilled piers may be considered to support the column loads for the proposed canopy and related improvements. Due to the presence of groundwater and highly cemented soils it will be difficult to construct underreamed piers. Therefore, only straight-sided piers will be addressed further in this report.

4.5.1.1 Straight-Sided Piers

Column loads for the canopy and other heavily loaded structure may be supported on straight-sided piers. The depth of the piers can be designed using the allowable bearing pressures presented below. Depending on the type of structure being supported, the straight-sided shafts should be sized for the following soil parameters:

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Net Allowable End

Bearing Elevation, ft Bearing Pressure, psf Net Allowable

Total Load Dead Load Side Friction, psf

Geotechnical Engineering Report U.S. Border Station Renovation ■ Laredo, Texas July 1, 2011 ■ Terracon Project No. 89115008

400-385 --- --- 200

385-370 7,500 5,000 300

370-355 15,000 10,000 600

355-3101 45,000 30,000 1,600 1The bearing pressures presented above are based on the piers bearing at least 3 feet into the Claystone Stratum. This stratum varies in depth as shown on the boring logs, thus resulting in different pier depths.

These bearing pressures include factors of safety against a bearing capacity failure of approximately 2 and 3, respectively. Piers should not extend deeper than El. 310 feet without contacting our office. The above bearing pressures assume that the bearing surface will be free and clean of loose debris.

The allowable side shear values in the above table have a factor of safety of at least 2. The side-shear should be neglected for:

Upper portion of the shaft where fill or loose soil is present (approximately 5- feet);

Within 1 pier diameter of the bottom of the shaft.

Expansive clay uplift on the piers is not a concern at this site. However, we recommend that the cross sectional area of the reinforcing steel be at least 1/2 percent of the gross cross-sectional area of the drilled pier shaft. The reinforcing steel should extend from the top to the depth of the shaft needed to resist the design uplift force.

The ultimate uplift resistance of the non-underreamed drilled piers can be evaluated using the following equation:

Qr = Σ(A·d·Dp) + Wp + PDL

Where: A = 0.5 between E1. 400 to 385 feet

A = 1.0 between E1. 385 to 370 feet

A = 2.5 between E1. 370 to 355 feet

A = 4.5 between E1. 355 to 310 feet

Qr = Ultimate uplift resistance of pier in kips (k) d = Diameter of pier shaft in feet (ft)

Dp = Length of pier shaft in contact with natural rock in feet (ft)

Wp = Weight of the drilled pier in kips (k)

PDL = Dead load acting on the drilled pier in kips (k)

We recommend that a factor of safety of at least 2 be applied to the computed ultimate uplift force. For adjacent piers, we recommend a minimum edge-to-edge spacing of at least 1 pier

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U.S. Border Station Renovation ■ Laredo, Texas July 1, 2011 ■ Terracon Project No. 89115008 diameter (or 2 pier diameters center-to-center) based on the larger diameter of the two adjacent piers. In locations where this minimum spacing criterion cannot be accomplished, Terracon should be contacted to evaluate the locations on a case-by-case basis.

Lateral Loading – Some of the drilled piers may be subjected to lateral loads due to wind pressures acting on the structures. A number of methods, including hand solutions and computer programs, are available for calculating the lateral behavior of piles and drilled piers.

The majority of these methods rely on “key” soil parameters such as soil elastic properties (E and ks), strain at 50 percent of the principal stress difference (50), undrained shear strength (c), and load-deflection (p-y) criteria. The p-y criteria, which are commonly used to model soil reaction, were developed from instrumented load tests and are generally considered to provide the best model of soil behavior under short-term lateral loading. The criteria for lateral load analysis presented on Table 1 are for use with the computer program series COM624/LPILE.

Settlement – For piers, total settlements, based on the indicated bearing pressures, should be about 1 inch or less for properly designed and constructed drilled piers. Settlement beneath individual piers will be primarily elastic with most of the settlement occurring during construction.

Differential settlement may also occur between adjacent piers. The amount of differential settlement could approach 50 to 75 percent of the total pier settlement. For properly designed and constructed piers, differential settlement between adjacent piers is estimated to be less than

3/4 of an inch. Settlement response of drilled piers is impacted more by the quality of construction than by soil-structure interaction. Improper pier installation could result in differential settlements significantly greater than we have estimated. In addition, larger magnitudes of settlement should be expected if the soil is subjected to bearing pressures higher than the allowable values presented in this report.

4.5.2 Drilled Pier Foundation Installation

Subsurface water was encountered in the borings in the vicinity of the proposed structures at different depths as shown in the boring logs. Subsurface water levels are influenced by seasonal and climatic conditions, which result in fluctuations in subsurface water elevations.

Additionally, it is common for water to be present after periods of significant rainfall. The foundation contractor should be prepared to utilize slurry or casing techniques to control sloughing of the sandy strata or subsurface water influx during excavation if they occur. Due to the presence of methane gas at the site, the contractor should choose the appropriate installation method.

Prior to any excavation, the foundation contractor should verify the subsurface water levels. The foundation contractor should consider performing a “test” pier excavation to determine the constructability of a drilled pier with the dry auger process. High-torque, high-powered (rock) drilling machinery equipped to cut and excavate rock will be required at this site. The slurry and casing methods of foundation installation are discussed in the following paragraphs.

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U.S. Border Station Renovation ■ Laredo, Texas July 1, 2011 ■ Terracon Project No. 89115008

Slurry Method – One method to install the pier foundations, water or a weighted drilling fluid may be considered. Slurry displacement drilling can only prevent sloughing and water influx but cannot control sloughing once it has occurred.

Therefore, slurry displacement drilling techniques must begin at the ground surface, not after sloughing materials are encountered.

Typical drilling fluids include those which contain polymers or bentonite. If a polymer is used with “hard” mixing water, a water softening agent may be required to achieve intimate mixing and the appropriate viscosity. The polymer manufacturer should be consulted concerning proper use of the polymer. If bentonite slurry is used, the bentonite should be mixed with water several hours before placing in the pier excavation. Prior mixing gives the bentonite sufficient time to hydrate properly. The drilling fluid should only be of sufficient viscosity to control sloughing of the excavation walls and subsurface water flow into the excavation. Care should be exercised while extracting the auger so that suction does not develop and cause disturbance or create “necking” in the excavation walls as described above. Casing should not be employed in conjunction with the slurry drilling technique due to possible trapping of loose soils and slurry between the concrete and natural soil.

The use of weighted drilling fluid when installing drilled pier foundations requires extra effort to ensure an adequate bearing surface is obtained. A clean-out bucket should be used just prior to pier completion in order to remove any cuttings and loose soils which may have accumulated in the bottom of the excavation. Steel and concrete should be placed in the excavation immediately after pier completion. A closed-end tremie should be used to place the concrete completely to the bottom of the excavation in a controlled manner to effectively displace the slurry during concrete placement.

When the pier excavation depth is achieved and the bearing area has been cleaned, steel and concrete should then be placed immediately in the excavation.

The concrete should be placed completely to the bottom of the excavation with a closed-end tremie in the pier excavation if more than 6 inches of water is ponded on the bearing surface or the slurry drilling technique is used. A short tremie may be used if the excavation has less than 6 inches of ponded water or if the water is pumped out prior to concrete placement. The fluid concrete should not be allowed to strike the pier reinforcement, temporary casing (if required) or excavation sidewalls during concrete placement.

Casing Method - Casing will provide stability of the excavation walls but may not completely eliminate subsurface water influx potential or stability of the pier excavation bottom unless the casing penetrates below any pervious soils.

Casing that terminates in pervious soils may generate “boils” due to the head differential between the inside and outside of the casing and require that the

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U.S. Border Station Renovation ■ Laredo, Texas July 1, 2011 ■ Terracon Project No. 89115008 casing be extended until the excess seepage or boils are eliminated. The actual casing depth should be chosen by the drilling subcontractor. If this operation is not successful or to the satisfaction of the engineer, the pier excavation should be flooded with fresh water to offset the differential water pressure caused by the unbalanced water levels inside and outside of the casing. When the pier excavation depth is achieved and the bearing area has been cleaned, steel and concrete should then be placed immediately in the excavation. If more than 6 inches of water is present in the excavation, water should be removed by pumping or the concrete should be tremied completely to the bottom of the excavation with a closed-end tremie.

Removal of casing should be performed with extreme care and under proper supervision to minimize mixing of the surrounding soil and water with the fresh concrete. Rapid withdrawal of casing or the auger may develop suction that could cause the soil to intrude into the excavation. An insufficient head of concrete in the casing during its withdrawal could also allow the soils to intrude into the wet concrete. Both of these conditions may induce “necking”, a section of reduced diameter, in the pier.

The foundation excavations should be augered and constructed in a continuous manner. The reinforcing steel and concrete should be placed in the excavations immediately following drilling and evaluation for proper bearing stratum, embedment, and cleanliness. Under no circumstances should the foundation excavations remain open overnight.

All aspects of concrete design and placement should comply with the American Concrete

Institute (ACI) 318-08 Code Building Code Requirements for Structural Concrete; ACI 336.1-01 entitled Reference Specification for the Construction of Drilled Piers, and ACI 336.3R-93

(Reapproved 2006) entitled Design and Construction of Drilled Piers. Concrete should be designed to achieve the specified 28-day strength when placed at a 7 inch slump with a 1 inch tolerance. Adding water to a mix that has been designed for a lower slump does not meet the intent of this recommendation. If a high range water reducer is used to achieve this slump, the span of slump retention for the specific admixture under consideration should be thoroughly investigated.