Retrofitted Bridge Fragility Curves for Assessing the Impact of Retrofit on Bridge System Performance

摘要

Many states in the Central and Southeastern United States (CSUS) are in the early phases of evaluating potential bridge vulnerability and assessing viable retrofit strategies for deficient bridges. While there are a host of potential retrofit strategies that exist for bridge types common to the CSUS, such as seat extenders, restrainer cables, isolation bearings, or steel jackets, each retrofit is generally targeted on the improving a particular deficiency. This paper evaluates the impact of retrofit measures on the response of various components including the columns, abutments, fixed and expansion bearings, as well as the impact of the retrofit on overall bridge system performance. The performance of the retrofitted bridge system is evaluated through a fragility curve, which offers the probability of the bridge being damaged beyond a given state for various levels of ground motion intensity. The analytical methodology for developing these retrofitted bridge fragility curves is presented, along with preliminary results for an example bridge class.