Seismic resilience analysis of a retrofit-required bridge considering moment-based system reliability

Abstract

For a bridge, its columns or piers, which are the main seismically resistant members of the bridge, are generally retrofitted to improve seismic performance. However, retrofitting may cause unexpected damage to the non-retrofitted components/members. Therefore, a corresponding retrofitting of these components/members should be considered as part of any retrofitting method to eliminate unexpected damage. This work is to develop an estimating procedure of the seismic reliability of the system for a bridge considering the seismic reliability of each specified component/member. Additionally, the damage state of bridge for the system reliability analysis is built based on the engineering judgement. For the convenience of the calculation, the seven-point estimation method and the Nataf transformation method are combined to calculate the first four moment values of a specified limit state function in the moment-based system reliability analysis. For determining the retrofitting strategy, this work also presents a method for calculating the relationship between the resilience in functionality and seismic intensity that is achieved using a particular retrofitting method. Moreover, the system reliability and recovery time of each damaged component/member are considered in a resilience analysis. Finally, a bridge is selected as an example to demonstrate the application of this work.