HANDBOOK FORBLAST-RESISTANTDESIGN OF BUILDINGS

Handbook for Blast-Resistant Design of Buildings Edited by Donald 0. Dusenberry

Copyright 0 2010 by John Wiley & Sons, Inc. All rights reserved.

HANDBOOK FORBLAST-RESISTANTDESIGN OF BUILDINGS

Edited by

Donald O. Dusenberry

JOHN WILEY & SONS, INC.

To my wife, Alice

This book is printed on acid-free paper. ∞©

Copyright C© 2010 by John Wiley & Sons, Inc. All rights reserved.

Published by John Wiley & Sons, Inc., Hoboken, New Jersey.Published simultaneously in Canada.

No part of this publication may be reproduced, stored in a retrieval system, or transmitted in anyform or by any means, electronic, mechanical, photocopying, recording, scanning, or otherwise,except as permitted under Section 107 or 108 of the 1976 United States Copyright Act, withouteither the prior written permission of the Publisher, or authorization through payment of theappropriate per-copy fee to the Copyright Clearance Center, 222 Rosewood Drive, Danvers, MA01923, (978) 750-8400, fax (978) 646-8600, or on the web at www.copyright.com. Requests to thePublisher for permission should be addressed to the Permissions Department, John Wiley & Sons,Inc., 111 River Street, Hoboken, NJ 07030, (201) 748-6011, fax (201) 748-6008, or online atwww.wiley.com/go/permissions.

Limit of Liability/Disclaimer of Warranty: While the publisher and the author have used their bestefforts in preparing this book, they make no representations or warranties with respect to theaccuracy or completeness of the contents of this book and specifically disclaim any impliedwarranties of merchantability or fitness for a particular purpose. No warranty may be created orextended by sales representatives or written sales materials. The advice and strategies containedherein may not be suitable for your situation. You should consult with a professional whereappropriate. Neither the publisher nor the author shall be liable for any loss of profit or any othercommercial damages, including but not limited to special, incidental, consequential, or otherdamages.

For general information about our other products and services, please contact our Customer CareDepartment within the United States at (800) 762-2974, outside the United States at (317)572-3993 or fax (317) 572-4002.

Wiley also publishes its books in a variety of electronic formats. Some content that appears in printmay not be available in electronic books. For more information about Wiley products, visit ourweb site at www.wiley.com.

Library of Congress Cataloging-in-Publication Data:

Handbook of blast resistant design of buildings / edited by Donald O. Dusenberry.p. cm.

Includes index.ISBN 978-0-470-17054-0 (cloth)

1. Building, Bombproof. I. Dusenberry, Donald O.TH1097.H36 2010693.8′54–dc22

2009019203ISBN: 978-0-470-17054-0

Printed in the United States of America

10 9 8 7 6 5 4 3 2 1

CONTENTS

Preface xv

Contributors xix

I DESIGN CONSIDERATIONS 1

1 General Considerations for Blast-Resistant Design 3Donald O. Dusenberry

1.1 Introduction 31.2 Design Approaches 41.3 The Blast Environment 51.4 Structure As an Influence on Blast Loads 61.5 Structural Response 81.6 Nonstructural Elements 91.7 Effect of Mass 101.8 Systems Approach 121.9 Information Sensitivity 131.10 Summary 14

References 15

2 Design Considerations 17Robert Ducibella and James Cunningham

2.1 Introduction 172.2 A New Paradigm for Designing Blast-Resistant Buildings,

Venues, and Sites 182.3 A Brief History of Recent Terrorist Attacks 21

2.3.1 Terrorists’ Use of Explosives 212.3.2 Vehicle-Borne Improvised Explosive Devices 222.3.3 Person-Borne Improvised Explosive Devices 242.3.4 Locally Available Explosives 252.3.5 Some Counterterrorism Considerations 27

2.4 Collaborating to Analyze Risk 282.4.1 Step 1—Threat Identification and Rating 282.4.2 Step 2—The Asset Value Assessment 312.4.3 Step 3—The Vulnerability Assessment 34

v

vi CONTENTS

2.4.4 Step 4—The Risk Assessment 382.4.5 Step 5—Considering Mitigation Options 392.4.6 The Continuing Role of Risk Management 40

2.5 Consequence Management 422.5.1 Consequence Evaluation 442.5.2 Function Redundancy 482.5.3 Building Location 512.5.4 Building Dispersal/Distribution of Functional Programs 542.5.5 Disaster Recovery and Contingency Planning 56

2.6 Threat Reduction 572.6.1 Accidental Explosions 592.6.2 Intentional Explosions 60

2.7 Vulnerability Reduction 632.7.1 Standoff Distance 642.7.2 Physical Security 652.7.3 Operational Security 652.7.4 Structural Design 65

2.8 Risk Acceptance 702.8.1 Design to Threat 712.8.2 Design to Budget 73

2.9 Some Recent Examples of Security Design “Best Practices” 752.10 Related Phenomena 76

2.10.1 Progressive Collapse 772.10.2 Disruption of Evacuation, Rescue, and

Recovery Systems 792.10.3 Attendant Fires 81

2.11 Security Design Consideration Guidelines 832.12 Conclusion 84

References 85

3 Performance Criteria for Blast-Resistant Structural Components 87Charles J. Oswald

3.1 Introduction 873.2 Building and Component Performance Criteria 883.3 Response Parameters 913.4 Empirical Correlations between Response Parameters

and Component Damage 953.5 Response Criteria Development 99

3.5.1 Explosive Safety Criteria 993.5.2 Response Criteria for Antiterrorism 1023.5.3 Response Criteria for Blast-Resistant Design of

Petrochemical Facilities 1053.5.4 Blast Resistant Doors 1073.5.5 Blast-Resistant Windows 109

CONTENTS vii

3.5.6 Response Criteria for Equivalent Static Loads 1123.5.7 Comparisons of Published Response Criteria 113

3.6 Response Criteria Limitations 114References 116

4 Materials Performance 119Andrew Whittaker and John Abruzzo

4.1 Introduction 1194.2 Structural Steel 119

4.2.1 Stress-Strain Relationships 1194.2.2 Constitutive Models for Structural Steel 1204.2.3 Component Level Strain Rate and Temperature Effects 1234.2.4 Mechanical Properties for Design 1254.2.5 Failure Modes of Structural Components 127

4.3 Reinforced Concrete 1294.3.1 Stress-Strain Relationships for Concrete 1294.3.2 Stress-Strain Relationships for Reinforcement 1324.3.3 Constitutive Modeling of Concrete and Rebar 1324.3.4 Component Level Strain-Rate Effects 1364.3.5 Mechanical Properties for Design 1384.3.6 Component-Level Failure Modes 141

4.4 Strength-Reduction Factors for Steel and Reinforced Concrete 144References 145

5 Performance Verification 149Curt Betts

5.1 Introduction 1495.2 Performance Verification 1495.3 Testing 150

5.3.1 Vehicle Barrier Testing 1505.3.2 Building Components 151

5.4 Analysis 1565.5 Peer Review 157

References 157

II BLAST PHENOMENA AND LOADINGS 159

6 Blast Phenomena 161Paul F. Mlakar and Darrell Barker

6.1 Introduction 1616.2 Sources of Blasts 1626.3 Characteristics of Blast Waves 170

viii CONTENTS

6.3.1 Key Parameters 1706.3.2 Scaling 171

6.4 Prediction of Blast Parameters 1726.4.1 High Explosives 1726.4.2 Bursting Pressure Vessels 1776.4.3 Vapor Cloud Explosions 178

6.5 Summary 181References 181

7 Blast Loading 183Paul F. Mlakar and William Bounds

7.1 Introduction 1837.2 Empirical Method 183

7.2.1 Empirical Method—Basic Blast Wave Example 1867.3 Front Wall Loads 186

7.3.1 Empirical Method—Front Wall Loading Example 1887.3.2 Empirical Method—Oblique Angle Example 192

7.4 Side Wall and Roof Loads 1927.4.1 Empirical Method—Side Wall Loading Example 1947.4.2 Empirical Method—Roof Loading Example 196

7.5 Rear Wall Loads 1977.5.1 Empirical Method—Rear Wall Loading Example 197

7.6 Confined Explosions 1987.7 Leakage 2067.8 Ray-Tracing Procedures 2087.9 Summary 212

References 212

8 Fragmentation 215Kim King

8.1 Introduction 2158.2 Debris 2158.3 Loadings 215

8.3.1 Primary Fragmentation 2168.3.2 Secondary Fragmentation 218

8.4 Design Fragment Parameters 2268.4.1 Fragment Final Velocity 2268.4.2 Fragment Trajectory 227

8.5 Fragment Impact Damage 2288.5.1 Fragment Penetration into Miscellaneous Materials

(THOR Equation) 2298.5.2 Steel 2318.5.3 Fragment Penetration into Concrete Targets 2338.5.4 Fragment Perforation of Concrete Targets 235

CONTENTS ix

8.5.5 Fragment Spalling of Concrete Targets 2368.5.6 Roofing Materials 2368.5.7 Other Materials 237References 237

III SYSTEM ANALYSIS AND DESIGN 239

9 Structural Systems Design 241Robert Smilowitz and Darren Tennant

9.1 General Discussion 2419.1.1 Seismic versus Blast 2419.1.2 Analytical Methods 243

9.2 Modeling 2449.2.1 Systems 2459.2.2 Materials 2469.2.3 Members 2489.2.4 Connections 251

9.3 Analytical Approaches 2529.3.1 P-I Diagrams 2529.3.2 Single-Element Analyses 2539.3.3 Structural Systems Response 2559.3.4 Explicit Dynamic Finite Element Analyses 255

9.4 Progressive Collapse 2569.4.1 European Guidance 2589.4.2 U.S. Guidance 258References 261

10 Building Envelope and Glazing 263Eve Hinman and Christopher Arnold

10.1 Design Intent 26310.1.1 Life Safety 26310.1.2 Emergency Egress and Facilitating Search

and Rescue 26410.1.3 Critical Functions (Protecting Equipment and

Business Processes) 26410.2 Design Approach 265

10.2.1 Response Criteria 26910.2.2 Static versus Dynamic 27010.2.3 Balanced Design 27010.2.4 Load Path 270

10.3 Fenestration 27210.3.1 Glass 27310.3.2 Mullions/Transoms 27810.3.3 Frame and Anchorage 279

x CONTENTS

10.3.4 Supporting Structure 28010.3.5 Other Penetrations 280

10.4 Exterior Walls 28110.4.1 Concrete Walls 28210.4.2 Masonry 28510.4.3 Steel 28510.4.4 Other 286

10.5 Roof Systems 28910.5.1 Concrete 28910.5.2 Steel 28910.5.3 Composite 29010.5.4 Penthouses/Gardens 290

10.6 Below Grade 29010.7 Reduction of Blast Pressures 292

References 294

11 Protection of Spaces 297MeeLing Moy and Andrew Hart

11.1 Areas Isolating Interior Threats 29711.2 Stairwell Enclosures 29811.3 Hardened Plenums 29811.4 Safe Havens 299

11.4.1 FEMA Documents 29911.4.2 Multi-Hazard Threats 30011.4.3 Design Requirements for Protective

Shelters 301References 305

12 Defended Perimeter 307Joseph L. Smith and Charles C. Ellison

12.1 Goals 30712.2 Standoff 307

12.2.1 Balancing Hardening with Standoff 30912.2.2 Balancing Costs 31112.2.3 Site Planning 313

12.3 Vehicle Control Barriers 31612.3.1 Crash Testing 31612.3.2 Crash Modeling 31712.3.3 Walls 31912.3.4 Bollards 31912.3.5 Active Wedge 32012.3.6 Beam Barriers 32012.3.7 Cable-Based Systems 323

CONTENTS xi

12.3.8 Planter and Surface Barriers 32412.3.9 Berms, Ditches, and Other Landscaping

Features 32412.4 Pedestrian Control Barriers 32512.5 Blast Walls and Berms 327

References 329

13 Blast-Resistant Design of Building Systems 331Scott Campbell and James Ruggieri

13.1 Background 33113.2 Introduction 33213.3 Design Considerations 333

13.3.1 Level of Protection 33413.3.2 Blast Pressures 33413.3.3 Shock Induced by the Structure 33513.3.4 Equipment/System Anchorage 33713.3.5 Placement of Critical Systems Equipment and

Control Stations 34013.3.6 Staffing and Building Operations 34013.3.7 Construction of Hardened Spaces 34113.3.8 HVAC and Plumbing Systems 34113.3.9 Electrical Systems 34413.3.10 Lighting Systems 34613.3.11 Other Systems/Considerations 346

13.4 Loading Calculation 34813.4.1 Blast Pressure 34913.4.2 In-Structure Shock 352

13.5 Summary 362References 363

IV BLAST-RESISTANT DETAILING 365

14 Blast-Resistant Design Concepts and Member Detailing 365Steven Smith and W. Gene Corley

14.1 General 36714.1.1 Scope 367

14.2 Failure Modes 36814.2.1 Flexural 36814.2.2 Diagonal Tension 36914.2.3 Direct Shear 36914.2.4 Membrane 36914.2.5 Stability 370

xii CONTENTS

14.3 Detailing 37014.3.1 General 37014.3.2 Splices 37114.3.3 Columns 37214.3.4 Beams 37514.3.5 Beam-Column Joints 37714.3.6 Slabs 37814.3.7 Walls 380References 380

15 Blast-Resistant Design Concepts and Member Detailing: Steel 383Charles Carter

15.1 General 38315.1.1 Typical Building Designs 38315.1.2 Prescriptive Building Designs 38415.1.3 Performance-Based Building Designs 385

15.2 Blast Effects on Structural Steel and Composite Structures 38615.2.1 Member Ductility 38615.2.2 Connection Ductility 38615.2.3 Overstrength 38615.2.4 Beneficial Strain-Rate Effects 38615.2.5 Beneficial Effects of Composite Construction 38715.2.6 Perimeter Column Design 38715.2.7 Perimeter Girder Design 38715.2.8 Slab Design 388

15.3 Analysis and Design of Structural Members 38815.4 Steel Material Properties for Blast Design 388

15.4.1 Strength Increase Factor (SIF) 38915.4.2 Dynamic Increase Factor (DIF) 38915.4.3 Dynamic Design Stress 390

15.5 Design Criteria for Blast Design 39015.5.1 General 39015.5.2 Load Combinations 39115.5.3 Resistance Factor and Factor of Safety 39115.5.4 Local Buckling 39115.5.5 Lateral-Torsional Buckling 39115.5.6 Deformation Criteria 39115.5.7 Detailing for Specific Failure Modes: 393

15.6 Examples 39715.6.1 Example 1—Determining Capacities 39715.6.2 Example 2—Design and Analysis for Blast Loads on

Members 40215.7 Design of Connections 418

References 419

CONTENTS xiii

16 Blast-Resistant Design Concepts and MemberDetailing: Masonry 421Shalva Marjanishvili

16.1 General Considerations 42316.1.1 Masonry 42416.1.2 Reinforcement 42416.1.3 Mortar 42516.1.4 Grout 42516.1.5 Construction Methods 425

16.2 Failure Modes 42616.2.1 Flexure 42816.2.2 Diagonal Tension Shear 43116.2.3 Direct Shear 43216.2.4 Breach and Spall Phenomena 432

16.3 Reinforced Masonry Detailing 43416.3.1 General 43516.3.2 Longitudinal Reinforcement 43516.3.3 Horizontal Reinforcement 43516.3.4 Walls 43816.3.5 Support Connections 438

16.4 Unreinforced Masonry 43916.4.1 Performance Evaluation 43916.4.2 Retrofit Recommendations 440References 442

17 Retrofit of Structural Components and Systems 445John E. Crawford and L. Javier Malvar

17.1 Introduction 44517.2 Retrofit of Columns 446

17.2.1 Reinforced Concrete Columns 44617.2.2 Steel Columns 454

17.3 Retrofit of Walls 45817.3.1 Masonry Walls 45817.3.2 Stud Walls 466

17.4 Floors 46617.5 Beams/Girders/Connections 46817.6 Structural System 46917.7 References 469

17.7.1 Inexact Science 46917.7.2 Complexities 470References 470

Index 477

PREFACE

The need for protection against the effects of explosions is not new. The useof explosive weaponry by the military necessitated resistive entrenchments agesago. Industrialization of our societies well over a century ago meant that weintended to manufacture, store, handle, and use explosives in constructive ways.To support these military and industrial purposes, a relatively small group ofdesigners have worked to devise ways to strengthen the blast resistance of ourstructures.

Early attempts at blast-resistance design necessarily relied on judgment, test,and trial-and-error construction to find the best solutions. As technology im-proved, designers became better able to predict the influences of explosionsand the resistive responses that they strove to impart into their designs. Morerecently, in the past several decades chemists, physicists, blast consultants, andstructural engineers have been empowered by technologies and computationaltools that have enhanced the precision of their analyses and the efficiency of theirdesigns.

At the same time, the need has increased. The small contingent of designersskilled in the art and science of creating structural designs that will resist ex-plosive forces has been joined by a larger group of architects, engineers, blastconsultants, and security consultants who are trying to respond to the increas-ing concern from a broader group of clients who fear an exposure that they didnot anticipate before and frequently did not bring upon themselves. Consultantswho have never before had to assess risks, devise risk-reduction programs, pro-vide security systems, establish design-base threats, calculate the pressures andimpulses from explosions, and create cost-effective structural designs are beingthrust into the process. Many are ill-trained to respond.

There are several good references on some of the aspects of designing forblast resistance. Some of these references support military purposes or for otherreasons have government-imposed restrictions against dissemination. As such,they are not widely available to consultants working in the private sector. Nearlyall those references and the references that are public each treat an aspect ofblast phenomenology, security systems, and structural design for blast resistance,but few, if any, bring together in one place discussions of the breadth of theissues that are important for competent designs. Consultants are forced to collecta library of references and extract from each the salient information that theythen synthesize into a comprehensive design approach.

xv

xvi PREFACE

In addition, practitioners who do receive the limited-distribution referencesfor the first time or who find references that are public usually discoverimmediately that designing for blast resistance is completely different from de-signing for any environmental load they encountered previously. Designers oftenrealize quickly that they are embarking on design process for which they do nothave the knowledge or experience for adequate competency. Those who do nothave this realization might be operating at risk if they are not careful and thor-ough students.

The purpose for this handbook is to bring together into one publication dis-cussions of the broad range of issues that designers need to understand if theyare to provide competent, functional, and cost-efficient designs. The contributorsto this book are among the most knowledgeable and experienced consultants andresearchers in blast resistant design, and contribute their knowledge in a collab-orative effort to create a comprehensive reference. Many of the contributors tothis handbook are collaborating in the development of the first-ever public-sectorstandard for blast resistant design, being developed contemporaneously with thishandbook by the Structural Engineering Institute (SEI) of the American Soci-ety of Engineers. While there undoubtedly will be some differences between theSEI standard and this handbook, many readers will consider these publicationsas companions.

This handbook is organized into four parts, each addressing a range of aspectsof blast-resistance design.

Part 1: Design Considerations provides an overview of basic principles.It has five chapters dealing with general considerations and the design pro-cess; risk analyses, reduction, and avoidance; criteria that establish accept-able performance; the science of materials performance under the extraordinaryblast environment; and performance verification for technologies and solutionmethodologies.

Part 2: Blast Phenomena and Loadings, in three chapters, describes theexplosion environment, loading functions to be used for blast response analysis,and fragmentation and associated methods for effects analyses.

Part 3: System Analysis and Design has five chapters that cover anal-ysis and design considerations for structures. This part instructs on struc-tural, building envelope, component space, site perimeter, and building systemdesigns.

Part 4: Blast-Resistant Detailing addresses detailing structural elements forresistance. Chapters on concrete, steel, and masonry present guidance that isgenerally applicable for new design. The fourth chapter addresses retrofits ofexisting structures.

I wish to thank all the contributors for their commitment to this work, theircollaborative spirit, and, of course, their willingness to share the blast-relatedexpertise that they have presented in their chapters. I wish to thank Steven Smithof CTLGroup in particular, for organizing and harmonizing the four chapters ofPart 4. William Zehrt of the Department of Defense Explosives Safety Boardimproved the quality of this handbook by reviewing the chapters of Part 2.

PREFACE xvii

I also wish to thank James Harper, Editor of John Wiley & Sons for sup-porting this effort; Daniel Magers, Senior Editorial Assistant, and Amy Odumfor her able supervision of the copyediting and production; and the copyeditors,compositors, typesetters, and others of the publisher’s staff who have profession-ally assembled this book and brought it to publication.

Donald O. DusenberryWakefield, Massachusetts

CONTRIBUTORS

John Abruzzo, P.E.PrincipalThornton Tomasetti555 12th Street, Suite 600Oakland, CA 94607Tel: (510) 433-9370JAbruzzo@ThorntonTomasetti.com

Christopher Arnold, FAIA, RIBAPresident, Building Systems

Development IncPalo Alto CA1248 Waverley StreetPalo Alto, CA 94301Tel: 650-462-1812chrisarno@aol.comchr.arnold@gmail.com

Curt P. Betts, P.E.Chief, Security Engineering SectionUS Army Corps of EngineersProtective Design Center1616 Capitol AvenueOmaha, Nebraska 68102-4901Tel: (402) 995-2359Curt.p.betts@usace.army.mil

Darrell D. Barker, P.E.Vice PresidentExtreme Loads and Structural

RiskABS Consulting14607 San Pedro Ave., Suite 215

San Antonio, Texas 78232Tel: (210) 495-5195dbarker@absconsulting.com

William Bounds, P.E.FluorPO Box 5014Sugar Land, Texas 77487william.bounds@fluor.com

Scott Campbell, Ph.D., P.E.Structural Analysis Consulting

GroupPO Box 91364Louisville, KY 40291Tel: (502) 762-9596scott@str-analysis.com

Charles CarterAmerican Institute of Steel

ConstructionOne East Wacker DriveSuite 700Chicago, Illinois 60601-1802Tel: (312) 670-2400carter@aisc.org

W. Gene Corley, Ph. D.CTLGroup5400 Old Orchard RoadSkokie, Illinois 60077-4321Tel: (847) 972-3060Fax: (847) 965-6541gcorley@ctlgroup.com

xix

xx CONTRIBUTORS

John E. CrawfordKaragozian & Case2550 N. Hollywood Way, Suite 500Burbank, CA 91505-5026Tel: (818) 240-1919crawford@kcse.com

James D. CunninghamWilliamsburg, VirginiaTel: (757) 645-4057jdcham@cox.net

Robert DucibellaSenior PrincipalDucibella Venter & SantoreSecurity Consulting EngineersSturbridge Commons – Franklin

House250 State StreetNorth Haven, CT 06473Tel: (203) 288-6490rducibella@dvssecurity.com

Donald O. Dusenberry, P.E.Senior PrincipalSimpson Gumpertz & Heger Inc.41 Seyon Street, Building 1, Suite 500Waltham, MA 02453Tel: (781) 907-9000dodusenberry@sgh.com

Chuck Ellison, P.E.Senior Security EngineerApplied Research Associates, Inc.119 Monument PlaceVicksburg, MS 39180Phone: (601)638-5401cellison@ara.com

Andrew Hart, Ph.D., MSc, BEng(Hons), Aff.M.ASCE

Martinez, CA 94553Tel: (925) 370-3866Hartliliana@aol.com

Eve Hinman, Eng.Sc.D., P.E.PresidentHinman Consulting Engineers, Inc.One Bush Street, Suite 510San Francisco, CA 94104Tel: (415) 621-4423ehinman@hce.com

Kim W. King, P.E.Director of Engineering2195 Redwoods CrestSan Antonio, TX 78232Tel: (210) 213-3737kimwking@yahoo.com

L. Javier MalvarNaval Facilities Engineering Service

Center1100 23rd AvenuePort Hueneme, CA 93043-4370luis.malvar@navy.mil

Shalva M. Marjanishvili, Ph.D.,P.E., S.E.

Technical DirectorHinman Consulting Engineers, Inc.One Bush Street, Suite 510San Francisco, CA 94104Tel: (415) 621-4423shalva@hce.com

Paul F. Mlakar, Ph.D., P.E.U.S. Army Engineer Research and

Development Center3909 Halls Ferry RoadVicksburg, MS 39180Tel: (601) 634-3251Paul.F.Mlakar@usace.army.mil

MeeLing Moy, P.E.PresidentThe Link CE, PLLCNew YorkTel: (646) 385-5096mmoy@thelinkce.com

CONTRIBUTORS xxi

Charles J. Oswald, Ph.D, P.E.Protection Engineering Consultants4203 Gardendale, Suite C112San Antonio, TX 78229Tel: (512) 380-1988coswald@protection-consultants.com

James Angelo Ruggieri, P.E.10710 Timberidge RoadFairfax Station, VA 22039Tel: (703) 250-3671ForensicX@cox.net

Robert Smilowitz, Ph.D., P.E.Weidlinger Associates, Inc.375 Hudson Street12th FloorNew York, New York 10014-3656Tel: (212) 367-3090smilowitz@wai.com

Joseph L. Smith, PSPSenior Vice PresidentApplied Research Associates, Inc.

119 Monument PlaceVicksburg, MS 39180Tel: (601) 638-5401jsmith@ara.com

Steven SmithCTLGroup10946 Eight Bells LaneColumbia, MD 21044Tel: (410) 997-0400sjsmith@ctlgroup.com

Darren TennantWeidlinger Associates, Inc.6301 Indian School Road, NE,

Suite #501Albuquerque, NM 87110Tel: (505) 349-2820tenant@wai.com

Andrew Whittaker, Ph.D., S.E.University at BuffaloBuffalo, NY 14260Tel: (716) 645-4364awhittak@buffalo.edu