TRANSPORTATION RESEARCH BOARD 2025 EXECUTIVE COMMITTEE*

OFFICERS

CHAIR: Leslie S. Richards, General Manager, Southeastern Pennsylvania Transportation Authority (SEPTA), Philadelphia

VICE CHAIR: Joel M. Jundt, Secretary of Transportation, South Dakota Department of Transportation, Pierre

EXECUTIVE DIRECTOR: Victoria Sheehan, Transportation Research Board, Washington, DC

MEMBERS

James F. Albaugh, President and CEO, The Boeing Company (retired), Scottsdale, AZ

Carlos M. Braceras, Executive Director, Utah Department of Transportation, Salt Lake City

Douglas C. Ceva, Vice President, Customer Lead Solutions, Prologis, Inc., Jupiter, FL

Nancy Daubenberger, Commissioner of Transportation, Minnesota Department of Transportation, St. Paul

Marie Therese Dominguez, Commissioner, New York State Department of Transportation, Albany

Garrett Eucalitto, Commissioner, Connecticut Department of Transportation, Newington

Andrew Fremier, Executive Director, Metropolitan Transportation Commission, San Francisco, CA

Martha Grabowski, Professor Emerita, Information Systems, Le Moyne College, Madden College of Business & Economics, Cazenovia, NY

Randell Iwasaki, President and CEO, Iwasaki Consulting Services, Walnut Creek, CA

Carol A. Lewis, Professor, Transportation Studies, Texas Southern University, Houston

Hani S. Mahmassani, W.A. Patterson Distinguished Chair in Transportation; Director, Transportation Center, Northwestern University, Evanston, IL

Scott C. Marler, Director, Iowa Department of Transportation, Ames

Ricardo Martinez, Adjunct Professor of Emergency Medicine, Emory University School of Medicine, Decatur, GA

Russell McMurry, Commissioner, Georgia Department of Transportation, Atlanta

Craig E. Philip, Research Professor and Director, VECTOR, Department of Civil and Environmental Engineering, Vanderbilt University, Nashville, TN

Steward T.A. Pickett, Distinguished Senior Scientist, Cary Institute of Ecosystem Studies, Millbrook, NY

Susan A. Shaheen, Professor and Co-Director, Transportation Sustainability Research Center, University of California, Berkeley

Marc Williams, Executive Director, Texas Department of Transportation, Austin

EX OFFICIO MEMBERS

Michael R. Berube, Deputy Assistant Secretary for Sustainable Transportation, U.S. Department of Energy, Washington, DC

Steven Cliff, Executive Officer, California Air Resources Board, Sacramento

LeRoy Gishi, Chief, Division of Transportation, Bureau of Indian Affairs, U.S. Department of the Interior, Germantown, MD

Firas Ibrahim, Director, Office of Research, Development, and Technology, Office of the Assistant Secretary for Research and Technology (OST-R), Washington, DC

Jason Kelly, Deputy Commanding General for Civil Works and Emergency Operations, U.S. Army Corps of Engineers, Washington, DC

Sandra Knight, President, WaterWonks, LLC, Washington, DC

Zahra “Niloo” Parvinashtiani, Engineer, Mobility Consultant Solutions, Iteris Inc., Fairfax, VA, and Chair, TRB Young Members Coordinating Council

Chris Rocheleau, Acting Administrator, Federal Aviation Administration, Washington, DC

Gloria Shepherd, Acting Deputy Administrator, Federal Highway Administration, Washington, DC

Karl Simon, Director, Transportation and Climate Division, U.S. Environmental Protection Agency, Washington, DC

Paul P. Skoutelas, President and CEO, American Public Transportation Association, Washington, DC

Jim Tymon, Executive Director, American Association of State Highway and Transportation Officials, Washington, DC

___________________

^* Membership as of February 2025.

NATIONAL COOPERATIVE HIGHWAY RESEARCH PROGRAM

Considerations for the Design and Construction of Bonded and Unbonded Post-Tensioned Concrete Bridge Elements

Robert J. Frosch
Christopher S. Williams
Sarah K. Bowlin
Mason B. Rhodes
David S. Derks
PURDUE UNIVERSITY
West Lafayette, IN

Pinar Okumus
Mi Jin Jung
UNIVERSITY AT BUFFALO
Buffalo, NY

Thomas P. Murphy
Maria Lopez de Murphy
MODJESKI AND MASTERS, INC.
Mechanicsburg, PA

Andrew D. Mish
Jesus Muro Villanueva
MODJESKI AND MASTERS, INC.
Littleton, CO

Subscriber Categories
Bridges and Other Structures • Construction • Materials

Research sponsored by the American Association of State Highway and Transportation Officials in cooperation with the Federal Highway Administration

NATIONAL COOPERATIVE HIGHWAY RESEARCH PROGRAM

Systematic, well-designed, and implementable research is the most effective way to solve many problems facing state department of transportation (DOT) administrators and engineers. Often, highway problems are of local or regional interest and can best be studied by state DOTs individually or in cooperation with their state universities and others. However, the accelerating growth of highway transportation results in increasingly complex problems of wide interest to highway authorities. These problems are best studied through a coordinated program of cooperative research.

Recognizing this need, the leadership of the American Association of State Highway and Transportation Officials (AASHTO) in 1962 initiated an objective national highway research program using modern scientific techniques—the National Cooperative Highway Research Program (NCHRP). NCHRP is supported on a continuing basis by funds from participating member states of AASHTO and receives the full cooperation and support of the Federal Highway Administration (FHWA), United States Department of Transportation.

The Transportation Research Board (TRB) of the National Academies of Sciences, Engineering, and Medicine was requested by AASHTO to administer the research program because of TRB’s recognized objectivity and understanding of modern research practices. TRB is uniquely suited for this purpose for many reasons: TRB maintains an extensive committee structure from which authorities on any highway transportation subject may be drawn; TRB possesses avenues of communications and cooperation with federal, state, and local governmental agencies, universities, and industry; TRB’s relationship to the National Academies is an insurance of objectivity; and TRB maintains a full-time staff of specialists in highway transportation matters to bring the findings of research directly to those in a position to use them.

The program is developed on the basis of research needs identified by chief administrators and other staff of the highway and transportation departments, by committees of AASHTO, and by the FHWA. Topics of the highest merit are selected by the AASHTO Special Committee on Research and Innovation (R&I), and each year R&I’s recommendations are proposed to the AASHTO Board of Directors, the FHWA, and the National Academies. Research projects to address these topics are defined by NCHRP, and qualified research agencies are selected from submitted proposals. Administration and oversight of research contracts are the responsibilities of NCHRP.

The needs for highway research are many, and NCHRP can make significant contributions to solving highway transportation problems of mutual concern to many responsible groups. The program, however, is intended to complement, rather than to substitute for or duplicate, other highway research programs.

NCHRP RESEARCH REPORT 1139

Project 12-118
ISSN 2572-3766 (Print)
ISSN 2572-3774 (Online)
ISBN 978-0-309-73419-6
Library of Congress Control Number 2025930870
Digital Object Identifier: 10.17226/29033

© 2025 by the National Academy of Sciences. National Academies of Sciences, Engineering, and Medicine and the graphical logo are trademarks of the National Academy of Sciences. All rights reserved.

COPYRIGHT INFORMATION

Authors herein are responsible for the authenticity of their materials and for obtaining written permissions from publishers or persons who own the copyright to any previously published or copyrighted material used herein.

Cooperative Research Programs (CRP) grants permission to reproduce material in this publication for classroom and not-for-profit purposes. Permission is given with the understanding that none of the material will be used to imply TRB, AASHTO, APTA, FAA, FHWA, FTA, GHSA, or NHTSA endorsement of a particular product, method, or practice. It is expected that those reproducing the material in this document for educational and not-for-profit uses will give appropriate acknowledgment of the source of any reprinted or reproduced material. For other uses of the material, request permission from CRP.

NOTICE

The research report was reviewed by the technical panel and accepted for publication according to procedures established and overseen by the Transportation Research Board and approved by the National Academies of Sciences, Engineering, and Medicine.

This material is based upon work supported by the FHWA under Agreement No. 693JJ32350025. The opinions, findings, and conclusions or recommendations expressed or implied in this publication are those of the researchers who performed the research and are not necessarily those of the Transportation Research Board; the National Academies of Sciences, Engineering, and Medicine; the FHWA; or the program sponsors.

The Transportation Research Board does not develop, issue, or publish standards or specifications. The Transportation Research Board manages applied research projects which provide the scientific foundation that may be used by Transportation Research Board sponsors, industry associations, or other organizations as the basis for revised practices, procedures, or specifications.

The Transportation Research Board; the National Academies of Sciences, Engineering, and Medicine; and the sponsors of the National Cooperative Highway Research Program do not endorse products or manufacturers. Trade or manufacturers’ names or logos appear herein solely because they are considered essential to the object of the report.

Published research reports of the

NATIONAL COOPERATIVE HIGHWAY RESEARCH PROGRAM

are available from

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The National Academy of Sciences was established in 1863 by an Act of Congress, signed by President Lincoln, as a private, nongovernmental institution to advise the nation on issues related to science and technology. Members are elected by their peers for outstanding contributions to research. Dr. Marcia McNutt is president.

The National Academy of Engineering was established in 1964 under the charter of the National Academy of Sciences to bring the practices of engineering to advising the nation. Members are elected by their peers for extraordinary contributions to engineering. Dr. John L. Anderson is president.

The National Academy of Medicine (formerly the Institute of Medicine) was established in 1970 under the charter of the National Academy of Sciences to advise the nation on medical and health issues. Members are elected by their peers for distinguished contributions to medicine and health. Dr. Victor J. Dzau is president.

The three Academies work together as the National Academies of Sciences, Engineering, and Medicine to provide independent, objective analysis and advice to the nation and conduct other activities to solve complex problems and inform public policy decisions. The National Academies also encourage education and research, recognize outstanding contributions to knowledge, and increase public understanding in matters of science, engineering, and medicine.

Learn more about the National Academies of Sciences, Engineering, and Medicine at www.nationalacademies.org.

The Transportation Research Board is one of seven major program divisions of the National Academies of Sciences, Engineering, and Medicine. The mission of the Transportation Research Board is to mobilize expertise, experience, and knowledge to anticipate and solve complex transportation-related challenges. The Board’s varied activities annually engage about 8,500 engineers, scientists, and other transportation researchers and practitioners from the public and private sectors and academia, all of whom contribute their expertise in the public interest. The program is supported by state departments of transportation, federal agencies including the component administrations of the U.S. Department of Transportation, and other organizations and individuals interested in the development of transportation.

Learn more about the Transportation Research Board at www.TRB.org.

COOPERATIVE RESEARCH PROGRAMS

CRP STAFF FOR NCHRP RESEARCH REPORT 1139

Monique R. Evans, Director, Cooperative Research Programs

Waseem Dekelbab, Deputy Director, Cooperative Research Programs, and Manager, National Cooperative Highway Research Program

Amir N. Hanna, Senior Program Officer

Oulimata Khoule, Senior Program Assistant

Natalie Barnes, Director of Publications

Heather DiAngelis, Associate Director of Publications

Brendan Foht, Senior Editor

NCHRP PROJECT 12-118 PANEL
Field of Design—Area of Bridges

Richard Brice, Washington State Department of Transportation, Tumwater, WA (Chair)

Hussam Z. Fallaha, Virginia Department of Transportation, Fairfax, VA

Gregg A. Freeby, American Segmental Bridge Institute, Austin, TX

Fouad A. H. Jaber, Nebraska Department of Transportation, Lincoln, NE

Thomas P. Macioce, HNTB, Carlisle, PA (formerly with Pennsylvania Department of Transportation, Harrisburg, PA)

Carin L. Roberts-Wollmann, Virginia Polytechnic Institute, Blacksburg, VA

Kevin Western, Michael Baker International, Inc., Osceola, WI

Reggie H. Holt, FHWA Liaison

FOREWORD

By Amir N. Hanna
Staff Officer
Transportation Research Board

NCHRP Research Report 1139: Considerations for the Design and Construction of Bonded and Unbonded Post-Tensioned Concrete Bridge Elements provides information on the different aspects of the design and construction of post-tensioned concrete bridge elements with unbonded tendons or a combination of bonded and unbonded tendons. The report includes a review of available information pertaining to post-tensioned concrete bridge elements incorporating unbonded tendons or a combination of bonded and unbonded tendons and considers both internal and external tendons. It also presents the findings of experimental and analytical investigations of the flexural, shear, and torsional behavior of such elements that provided a basis for suggested enhancements for consideration in the design and construction procedures for post-tensioned concrete bridge elements with unbonded tendons. The information contained in the report will be of immediate interest to bridge engineers and others involved in the design and construction of highway bridges and structures.

Grouted tendons are predominantly used for post-tensioned concrete bridge elements in the United States. However, because of potential durability issues with grouted tendons, some highway agencies have opted to use ungrouted tendons for post-tensioning to facilitate replacement. Combinations of bonded and unbonded tendons as well as internal and external tendons or combinations thereof have been used for such applications. Although current bridge design and construction procedures address the design and construction of post-tensioned concrete bridge elements, some aspects pertaining to this variety of tendon application are not adequately addressed or evaluated. Research was needed to review available information, perform necessary analytical and experimental evaluations, and propose enhancements to current design and construction procedures to ensure appropriate consideration of the effects of tendon configuration on the design and construction of post-tensioned concrete bridge elements.

Under NCHRP Project 12-118, “Design and Construction Specifications for Bonded and Unbonded Post-Tensioned Concrete Bridge Elements,” Purdue University was tasked with proposing enhancements to current bridge design and construction procedures for post-tensioned concrete bridge elements with unbonded tendons or a combination of bonded (pretensioned or post-tensioned) and unbonded tendons. To accomplish this objective, the research team identified and reviewed relevant information, and conducted experimental and analytical investigations of the flexural, shear, and torsional behavior of bridge elements. Findings of these investigations provided a basis for identifying suggested considerations to enhance the current design and construction procedures, and developing recommended draft language, for consideration by AASHTO, to incorporate the research results into a future edition of AASHTO’s LRFD Bridge Design Specifications and better address the design

CONTENTS

Chapter 1 Introduction

1.1 Background

1.2 Objective

Chapter 2 Literature and Specification Review

2.1 Introduction

2.2 Flexural Strength

2.2.1 Members with Bonded Strands in Flexure

2.2.2 Members with Unbonded Internal Strands in Flexure

2.2.3 Members with Unbonded External Strands in Flexure

2.2.4 Members with Both Bonded and Unbonded Strands in Flexure

2.3 Shear Strength

2.3.1 Introduction

2.3.2 Members with Bonded Strands in Shear

2.3.3 Members with Unbonded Internal Strands in Shear

2.4 Torsional Strength

2.5 AASHTO Specification Limitations

Chapter 3 Experimental Investigations

3.1 Introduction

3.2 Materials

3.2.1 Concrete

3.2.2 Grout

3.2.3 Prestressing Steel

3.2.4 Mild Reinforcement

3.2.5 Post-tensioning Ducts

3.3 Test Series 1

3.3.1 Specimen Design

3.3.2 Specimen Construction

3.3.3 Flexure

3.3.4 Shear

3.3.5 Torsion

3.4 Test Series 2

3.4.1 Specimen Design

3.4.2 Test Setup and Instrumentation

3.4.3 Results

3.4.4 Test Series 2 Conclusions

Chapter 4 Analytical Investigations

4.1 Introduction

4.2 Flexural Analysis

4.2.1 Sectional Analysis

4.2.2 Material Models for SA

4.2.3 Validation of Modeling Techniques for SA

4.2.4 Parametric Analysis

4.3 Shear Analysis

4.3.1 MCFT-Based Analysis

4.3.2 Material Models for MCFTA

4.3.3 Validation of Modeling Techniques for MCFTA

4.3.4 Parametric Analysis

4.4 Torsional Analysis

4.4.1 Finite Element Analysis

4.4.2 Material Models for FEA

4.4.3 Validation of Modeling Techniques for FEA

4.4.4 Parametric Analysis

Chapter 5 Summary and Recommendations for Future Research

5.1 Summary of Research Findings

5.1.1 Flexure

5.1.2 Shear

5.1.3 Torsion

5.2 Recommendations for Future Research

5.2.1 Flexure

5.2.2 Shear

5.2.3 Torsion

References and Bibliography

Abbreviations and Acronyms