Abstracts

The Multi Span Simply Supported (MSSS) bridge system is the most commonly used structural system for High Speed Railway (HSR) networks in China. With China Railway rapidly expanding to the southwestern region of China, an area of high seismic activity, significant concerns have been raised to confirm whether the conventional HSR MSSS bridge, designed for low seismic zones, can be used in areas of high earthquake shaking intensities. In this thesis, the performance-based earthquake engineering (PBEE) methodology, originally developed for the seismic performance assessment of buildings, has been modified and applied to quantify the direct seismic loss of the Chinas HSR MSSS bridge system. This study is the first of its kind to systematically define and quantify the damage states, and associated repair actions, repair costs and travel delay losses for the Chinas HSR MSSS bridge system. The developed loss assessment model can be employed to assess the seismic performance of the HSR MSSS bridge system in diverse regions of China. In this study, a detailed parameter study using a framework developed in this thesis was utilized to study the influence of the shear capacity of fixed bearings on the seismic performance of a typical four-span HSR MSSS bridge system located in the Sichuan-Yunnan region in China. The results reveal that the financial loss of the HSR MSSS bridge system is highly dependent on the shear strength of the fixed bearing. Overall, the travel delay costs outweigh those for structural repair, where most of the financial loss was attributed to loss of functionality and repairs of the track-slab system and the bearings of the HSR MSSS bridge system. In addition, the developed fragility data and PBEE framework were used to optimize the design of the HSR MSSS bridge system using friction pendulum devices. The results show that the most optimal seismic loss of the isolated HSR MSSS bridge system can be reduced by 90% when compared to the that in the absence of seismic isolation.