COMPREHENSIVE DESIGN EXAMPLE FOR PRESTRESSED CONCRETE (PSC) GIRDER SUPERSTRUCTURE BRIDGE WITH COMMENTARY (Task order DTFH61-02-T-63032) US CUSTOMARY UNITS Submitted to THE FEDERAL HIGHWAY ADMINISTRATION Prepared By Modjeski and Masters, Inc. Archived November 2003 Technical Report Documentation Page 1. Report No. 2. Government Accession No. 3. Recipient’s Catalog No. FHWA NHI - 04-043 4. Title and Subtitle 5. Report Date Comprehensive Design Example for Prestressed Concrete (PSC) November 2003 Girder Superstructure Bridge with Commentary 6. Performing Organization Code (in US Customary Units) 7. Author (s) Wagdy G. Wassef, Ph.D., P.E., Christopher Smith, E.I.T. 8. Performing Organization Report No. Chad M. Clancy, P.E., Martin J. Smith, P.E. 9. Performing Organization Name and Address 10. Work Unit No. (TRAIS) Modjeski and Masters, Inc. P.O.Box 2345 11. Contract or Grant No. Harrisburg, Pennsylvania 17105 DTFH61-02-D-63006 12. Sponsoring Agency Name and Address 13. Type of Report and Period Covered Federal Highway Administration Final Submission National Highway Institute (HNHI-10) August 2002 – November 2003 4600 N. Fairfax Drive, Suite 800 14. Sponsoring Agency Code Arlington, Virginia 22203 15. Supplementary Notes Modjeski and Masters Principle Investigator and Project Manager : Wagdy G. Wassef , Ph.D., P.E. FHWA Contracting Officer’s Technical Representative: Thomas K. Saad, P.E. Team Leader, Technical Review Team: Jerry Potter, P.E. 16. Abstract This document consists of a comprehensive design example of a prestressed concrete girder bridge. The superstructure consists of two simple spans made continuous for live loads. The substructure consists of integral end abutments and a multi-column intermediate bent. The document also includes instructional commentary based on the AASHTO-LRFD Bridge Design Specifications (Second Edition, 1998, including interims for 1999 through 2002). The design example and commentary are intended to serve as a guide to aid bridge design engineers with the implementation of the AASHTO- LRFD Bridge Design Specifications. This document is offered in US Customary Units. An accompanying document in Standard International (SI) Units is offered under report No. FHWA NHI-04-044. This document includes detailed flowcharts outlining the design steps for all components of the bridge. The flowcharts are cross-referenced to the relevant specification articles to allow easy navigation of the specifications. Detailed design computations for the following components are included: concrete deck, prestressed concrete I-girders, elastomeric bearing, integral abutments and wing walls, multi-column bent and pile and spread footing foundations. In addition to explaining the design steps of the design example, the comprehensive commentary goes beyond the specifics of the design example to offer guidance on different situations that may be encountered in other bridges. 17. Key Words 18. Distribution Statement Bridge Design, Prestressed Concrete, Load and Resistance This report is available to the public from the Factor Design,Archived LRFD, Concrete Deck, Intermediate Bent, National Technical Information Service in Integral Abutment, Wingwall, Pile Foundation, Spread Springfield, Virginia 22161 and from the Footings Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402. 19. Security Classif. (of this report) 20. Security Classif. (of this page) 21. No. of Pages 22. Price Unclassified Unclassified 381 Form DOT F 1700.7 (8-72) Reproduction of completed page authorized This page intentionally left blank Archived ACKNOWLEDGEMENTS The authors would like to express appreciation to the review teams from the Illinois Department of Transportation, Minnesota Department of Transportation and Washington State Department of Transportation for providing review and direction on the Technical Review Committee. The authors would also like to acknowledge the contributions of Dr. John M. Kulicki, President/CEO and Chief Engineer of Modjeski and Masters, Inc., for his guidance throughout the project. Archived Table of Contents Prestressed Concrete Bridge Design Example TABLE OF CONTENTS Page 1. INTRODUCTION .........................................................................................................1-1 2. EXAMPLE BRIDGE ....................................................................................................2-1 2.1 Bridge geometry and materials.............................................................................2-1 2.2 Girder geometry and section properties ...............................................................2-4 2.3 Effective flange width ........................................................................................2-10 3. FLOWCHARTS ............................................................................................................3-1 4. DESIGN OF DECK .......................................................................................................4-1 5. DESIGN OF SUPERSTRUCTURE 5.1 Live load distribution factors ..............................................................................5-1 5.2 Dead load calculations.......................................................................................5-10 5.3 Unfactored and factored load effects.................................................................5-13 5.4 Loss of prestress ...............................................................................................5-27 5.5 Stress in prestressing strands.............................................................................5-36 5.6 Design for flexure 5.6.1 Flexural stress at transfer ......................................................................5-46 5.6.2 Final flexural stress under Service I limit state ....................................5-49 5.6.3 Longitudinal steel at top of girder.........................................................5-61 5.6.4 Flexural resistance at the strength limit state in positive moment region .....................................................................................5-63 5.6.5 Continuity correction at intermediate support ......................................5-67 5.6.6 Fatigue in prestressed steel ...................................................................5-75 5.6.7 Camber..................................................................................................5-75 5.6.8 Optional live load deflection check ......................................................5-80 5.7 Design for shear ................................................................................................5-82 5.7.1 Critical section for shear near the end support......................................5-84 5.7.2 Shear analysis for a section in the positive moment region..................5-85 5.7.3 Shear analysis for sections in the negative moment region ..................5-93 5.7.4 Factored bursting resistance................................................................5-101 5.7.5 Confinement reinforcement ................................................................5-102 5.7.6 Force in the longitudinal reinforcement including the effect of the applied shear .................................................................................5-104 Archived 6. DESIGN OF BEARINGS .............................................................................................6-1 Task Order DTFH61-02-T-63032 i Table of Contents Prestressed Concrete Bridge Design Example 7. DESIGN OF SUBSTRUCTURE ..................................................................................7-1 7.1. Design of Integral Abutments 7.1.1 Gravity loads...........................................................................................7-6 7.1.2 Pile cap design .....................................................................................7-11 7.1.3 Piles.......................................................................................................7-12 7.1.4 Backwall design....................................................................................7-16 7.1.5 Wingwall design ...................................................................................7-30 7.1.6 Design of approach slab........................................................................7-34 7.1.7 Sleeper slab ...........................................................................................7-37 7.2. Design of Intermediate Pier 7.2.1 Substructure loads and application .......................................................7-38 7.2.2 Pier cap design ......................................................................................7-51 7.2.3 Column design ......................................................................................7-66 7.2.4 Footing design.......................................................................................7-75 Appendix A - Comparisons of Computer Program Results (QConBridge and Opis) Section A1 - QConBridge Input.............................................................................................. A1 Section A2 - QConBridge Output........................................................................................... A3 Section A3 - Opis Input......................................................................................................... A10 Section A4 - Opis Output...................................................................................................... A47 Section A5 - Comparison Between the Hand Calculations