Time-Dependent Reliability of PSC Box-Girder Bridge Considering Creep, Shrinkage, and Corrosion |
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Authors: | Tong Guo Richard Sause Dan M. Frangopol Aiqun Li |
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Affiliation: | 1Associate Professor, Key Laboratory of Concrete and Prestressed Concrete Structure, Ministry of Education, Southeast Univ., Nanjing 210096, People’s Republic of China; formerly, Visiting Research Scientist, ATLSS Center, Lehigh Univ., 117 ATLSS Dr., Bethlehem, PA 18015 (corresponding author). E-mail: guotong77@gmail.com 2Joseph T. Stuart Professor of Structural Engineering and Director, Dept. of Civil and Environmental Engineering, ATLSS Center, Lehigh Univ., 117 ATLSS Dr., Bethlehem, PA 18015. E-mail: rs0c@lehigh.edu 3Professor and Fazlur R. Khan Endowed Chair of Structural Engineering and Architecture, Dept. of Civil and Environmental Engineering, ATLSS Center, Lehigh Univ., 117 ATLSS Dr., Bethlehem, PA 18015. E-mail: dan.frangopol@lehigh.edu 4Professor, College of Civil Engineering, Southeast Univ., Nanjing 210096, People’s Republic of China. E-mail: aiqunli@seu.edu.cn
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Abstract: | Bridge performance undergoes time-varying changes when exposed to aggressive environments. While much work has been done on bridge reliability under corrosion, little is known about the effects of creep and shrinkage on the reliability of concrete bridges. In this paper, the CEB-FIP model for creep and shrinkage is applied by using finite-element (FE) analysis in conjunction with probabilistic considerations. Verification is made by comparing the analytical findings with existing test data. More specifically, a time-dependent reliability assessment is made for a composite prestressed concrete (PSC) box-girder bridge exposed to a chloride environment. This realized via an advanced probabilistic FE method. The postcracking behavior of the thin-walled box girder is described using composite degenerated shell elements, and importance sampling is used to improve the efficiency of the reliability analyses. It is shown that concrete creep and shrinkage dominate during the early stages of bridge structure deterioration. This is accompanied by a decrease in reliability owing to the combined action of creep, shrinkage, and corrosion. The reliability indexes for the serviceability and the tendon yielding limit state fall below the target levels prior to the expected service life. Therefore, early maintenance and/or repair measures are required. |
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Keywords: | Prestressed concrete Box girders Creep Shrinkage Corrosion Probability Finite element method |
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