Abstract
In this study, the authors develop a methodology for determining the optimal inspection cycle of a long span bridge, based on the minimization of total cost, which is defined as the sum of lifecycle and risk costs. As a concrete deterioration phenomenon, this study is focused on steel corrosion. Firstly, a sample path of the steel corrosion process for each member is formed with the theoretical equation for corrosion, and the ultimate limit of corrosion is calculated through structural analysis. Secondly, the authors formulate a statistical model based on the weighted average of sample paths, and propose a hybrid deterioration prediction method for modifying it with visual inspection data. Next, based on the results of the hybrid deterioration prediction, the authors calculate the probability and cost of the risk of bridge collapse with (1) lifecycle cost and (2) fault tree analysis, and determine optimal inspection cycle. In addition, the proposed method is applied to the issue of determining the inspection cycle for a long span bridge, and its effectiveness is discussed empirically.
