Utah State University LIVE-LOAD TESTING AND FINITE-ELEMENT ANALYSIS OF A STEEL CANTILEVERED DECK ARCHED PRATT TRUSS BRIDGE FOR THE LONG-TERM BRIDGE PERFORMANCE PROGRAM by Matthew P. Laurendeau A thesis submitted in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE in Civil and Environmental Engineering Approved: __________________________________ ____________________________________ Paul J. Barr Marvin W. Halling Major Professor Committee Member __________________________________ __________________________________ Joseph A. Caliendo Byron R. Burnham Committee Member Dean of Graduate Studies UTAH STATE UNIVERSITY Logan, Utah 2011 ii Copyright © Matthew P. Laurendeau 2011 All Rights Reserved iii ABSTRACT Live-Load Testing and Finite-Element Analysis of a Steel Cantilevered Deck Arched Pratt Truss Bridge for the Long-Term Bridge Performance Program by Matthew P. Laurendeau, Master of Science Utah State University, 2011 Major Professor: Dr. Paul J. Barr Department: Civil and Environmental Engineering The Long Term Bridge Performance (LTBP) program is an organization within the Federal Highway Administration that inspects, tests, analyzes, and observes, for an extended period of time, a variety of bridge types throughout the United States. Part of the program includes periodic testing of select bridges of a span of 20 years. The Kettle River Bridge located outside of Sandstone, Minnesota was selected for study due to its unique design. The Kettle River Bridge is a historical steel cantilevered deck arched Pratt truss bridge. The bridge was instrumented with 151 strain gauges on various floor and truss members along with eight displacement gauges strategically placed along the truss. All gauges were read simultaneously as the bridge underwent non- destructive live loading. The recorded gauge readings were analyzed to determine bridge behavior and then used in the assistance of calibrating a working finite- element model. iv After a working model was verified the distribution factors for the interior and exterior floor stringers were determined. By using the controlling distribution factor, a load rating for the bridge was determined for both inventory and operating. The distribution factors and load ratings determined using the working finite- element model were then compared to the AAHSTO LRFD specifications. (180 pages) v ACKNOWLEDGMENTS I would like to thank all those who have helped make this research possible. First, I would like to thank my wife, Amanda, for always being there and supporting me in every way she knew how and continues to unconditionally give that support. I would also like to thank my family who have always believed in me and encouraged me to always do my best. Also, to my fellow colleagues, I would like to say thank you for being a great help by expounding on certain key principles. I would also like to thank the help of Bridge Diagnostics Inc. (BDI) for their help in the instrumentation, collection, and correlation of measured gauge readings for the Kettle River Bridge. Thank you to Kayde Roberts for providing some of the quality photographs used in this thesis. Finally, I would like to make a special thanks to Dr. Paul Barr who oversaw the research of this thesis. The kindness, enthusiasm, support, encouragement, and relentless assistance he provided never went unnoticed and shall never be forgotten. Matthew Laurendeau vi CONTENTS Page ABSTRACT ................................................................................................................................................ iii ACKNOWLEDGMENTS .......................................................................................................................... v LIST OF TABLES ..................................................................................................................................... ix LIST OF FIGURES .................................................................................................................................... x CHAPTER 1. INTRODUCTION ..................................................................................................................... 1 Introduction .......................................................................................................................... 1 Organization .......................................................................................................................... 5 2. LITERATURE REVIEW ......................................................................................................... 7 Introduction .......................................................................................................................... 7 Hao (2010) .................................................................................................................... 8 Trautner (1989) ........................................................................................................... 9 Boothby and Craig (1997) ..................................................................................... 11 Mabsout et al. (1997) .............................................................................................. 12 Bowen (2003)............................................................................................................. 13 Yost et al. (2005) ....................................................................................................... 15 3. LIVE-LOAD TESTING ......................................................................................................... 17 Bridge Description ........................................................................................................... 17 Instrumentation Plan...................................................................................................... 28 Live-load Testing .............................................................................................................. 35 Strain Results ..................................................................................................................... 39 Floor stringer strains ............................................................................................... 40 Truss member strains ............................................................................................. 47 Displacement Results ..................................................................................................... 52 High Speed Dynamic Results ....................................................................................... 54 4. FINITE-ELEMENT MODEL .............................................................................................. 60 vii Finite-Element Model Description ............................................................................ 60 Strain Comparisons ......................................................................................................... 72 Floor stringer strain comparisons ..................................................................... 72 Truss member strain comparisons .................................................................... 78 Displacement Comparisons ......................................................................................... 82 Load Distribution Factor ............................................................................................... 88 AASHTO live load distribution factors .............................................................. 89 Finite-element model distribution factors ...................................................... 93 Load Rating ......................................................................................................................... 97 5. SUMMARY AND CONCLUSIONS .................................................................................. 101 Summary ........................................................................................................................... 101 Conclusions....................................................................................................................... 102 REFERENCES ....................................................................................................................................... 104 APPENDICES ........................................................................................................................................ 105 Appendix A: Member Sizes ................................................................................................ 106 Appendix B: Instrumentation Plans ............................................................................... 109 Appendix C: As-Built Model Comparisons ................................................................... 120 Appendix D: Floor System Strain .................................................................................... 124 Floor Stringer Cross Section Comparisons .......................................................... 125 Floor Stringer Influence Line Comparisons ......................................................... 128 Floor Beam Strain Influence Line ............................................................................ 138 Floor Stringer Correlations ........................................................................................ 139 Appendix E: Truss Member Strain .................................................................................. 140 Truss Member Strain Influence Lines .................................................................... 141 Truss Member Strain Correlations .......................................................................... 148 Truss Member Bending Strains ................................................................................ 149 Appendix F: Displacements ............................................................................................... 152 Displacement Influence Lines ................................................................................... 153 Displacement Correlations ......................................................................................... 161 viii Appendix G: High Speed Dynamic Results................................................................... 162 ix LIST OF TABLES Table Page 1 AASHTO Distribution Factors ................................................................................................. 93 2 AASHTO and FEM Distribution Factor Comparison ....................................................... 97 3 AAHSTO LFD, LRFR, and FEM Load Rating Comparison ............................................ 100