OPTIMUM INSPECTION POLICY FOR LONG SPAN BRIDGE BASED ON FAULT TREE ANALYSIS WITH VISUAL INSPECTION DATA

Abstract

 This paper proposes a decision making methodology on an optimal inspection method/cycle for long span bridges, based on the two evaluation items: lifecycle cost and risk probability. Firstly, the authors formulate the aggregative Markov deterioration hazard model using visual inspection data, and propose a model for minimizing lifecycle cost. In addition, the authors express the risk of the management limit in the visual inspection of a long bridge with a fault tree, and calculate the probabilities of events constituting the fault tree with the Markov transition probability. Then, it becomes possible to grasp the variation in risk probability due to the difference in inspection and repair policies. Finally, the proposed method is applied to the actual case of determining an optimal inspection policy, to discuss its effectiveness empirically.