Development of Seismic Damage Evaluation System for Bridge Structures by Using Damage Transition Model

The Great Hanshin Earthquake had affected seriously on many highway bridges in Hanshin area. From a lot of investigations about the failure mechanisms on the highway bridges during strong earthquake, it was found that the consideration as a highway bridge system which consists of many structural elements such as piles, footings, piers, bearings, restrainers, super structures, etc. is very important to improve the practical design procedure. In this paper, an evaluation method for multiple damage states of bridge structural system due to strong earthquake is proposed. Then, the bridge structures were divided into each structural element from a systematic point of view, and these elements are interacted each other. Therefore, probability of multiple damage states of structural elements are evaluated by Marcov-chain model based on a damage transition probability matrix which can include damage interaction between the elements. The probability of multidamage-states for the bridges with countermeasures against earthquakes such as strengthening work for pier, base isolation and fuse type bearing is calculated, and improvement in earthquake resistance of these bridges was estimated quantitatively.