Simplified structural deterioration model for reinforced concrete bridge piers under cyclic loading¹

¹This paper is part of the keynote lecture presented by Professor Anne Kiremidjian on ‘Time-dependent earthquake risk assessment modeling considering sustainability metrics’ at the IALCCE 2014, Tokyo, Japan.

Abstract

Deterioration due to reinforcement corrosion represents a significant cause of damage to reinforced concrete bridges all over the world. Although numerous studies have identified the substantial influence that corrosion can have on the failure of concrete structures under seismic loads, there has been comparatively less work done on the modelling of structural vulnerability due to corrosion. Accurate and computationally efficient structural modelling of corrosion deterioration is an essential prerequisite for structural reliability or fragility prediction, or life cycle cost and impact estimation. In this paper, a simplified approach for modelling reinforced concrete bridge columns that have undergone deterioration due to chloride-induced reinforcement corrosion is presented. While several models of increasing complexity are evaluated, a simplified non-linear analytical model that accounts primarily for the reduction in the steel cross-section due to corrosion is the central focus of the paper. The accuracy of the simple model is validated by comparing analytical results with experimental tests on reinforced concrete columns subjected to accelerated corrosion. The model results show excellent agreement with the experimental tests, making it particularly suitable for applications in vulnerability or reliability analysis where numerous non-linear dynamic analyses are necessary, or for further downscale or upscale integration with materials-level or system-level models.

Keywords:

• Structural deterioration
• reinforced concrete
• bridge columns
• rebar corrosion
• dynamic fragility functions
• non-linear modelling
• model validation

Acknowledgements

The authors would like to thank the financial support of National Natural Science Foundation of China (50808158), the National High Technology Research and Development Program of China (2007AA04Z437), the Blume Earthquake Engineering Research Center, the Leavell Fellowship, and the Terman Faculty Fellowship at Stanford University. The authors would also like to thank Professor Wilkins Aquino from the Department of Civil and Environmental Engineering, Duke University, Durham, NC, and Jinbo Li and Professor Jinxin Gong from The State Key Laboratory of Coastal and Offshore Engineering, Dalian University of Technology, Dalian City, Liaoning Province, People’s Republic of China for the use of their data from the cyclic load tests. The research presented in this paper was partially supported through U.S. NSF Grants CMMI-106756 and NEESR-105651. Any opinions, findings, conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the U.S. National Science Foundation.

Notes

¹ This paper is part of the keynote lecture presented by Professor Anne Kiremidjian on ‘Time-dependent earthquake risk assessment modeling considering sustainability metrics’ at the IALCCE 2014, Tokyo, Japan.