考慮系統功能影響之橋梁補強工程效益研究

For the benefit evaluation of the seismic retrofit of a bridge, how to estimate the occurrence probabilities of various damage states is needed at first. Generally, for a bridge structure, the performance curve obtained from the pushover analysis, which represents the seismic performance of piers, is used to define the various damage states of the bridge under earthquake. However, the damage states of components or elements, such as the bearing, prevention device of bridge falling, cap beam, and foundations are not considered to define the various states of the bridge. Therefore, each damage state of a bridge structure should be defined based on the performance functions of components or elements. Additionally, this paper adopts the system reliability method to estimate the occurrence probabilities of each damage state of a bridge structure including damage states of specified components or members. For the social cost within the seismic retrofit, this work adopts various recovery functions related to various damage states to consider the change of the transportation capacity under the seismic retrofit. Additionally, according to the benefit-cost ratio, the returning period of the seismic retrofitting investment can be estimated. Finally, two reinforced concrete bridges in Taipei are selected in the case study to demonstrate the application of the proposed estimation procedure.