OPTIMUM BRIDGE INSPECTION/REPAIR ARRANGEMENT BASED ON TIME-DEPENDENT RELIABILITY AND PRE-POSTERIOR DECISION

On the basis of time-dependent reliability of deteriorating RC bridges due to pitting corrosion induced by chloride attack and average corrosion induced by concrete carbonation, bridge inspection/repair arrangement is optimized by using pre-posterior decision analysis exploring utilities of bridge inspections while utility functions relating owners’ financial capacity and risk-adverse psychology are used. Optimization of the bridge inspection/repair arrangement is maximizing the direct monetary reward or utility function with a condition that the bridge time-dependent reliability is not larger than the target reliability behind the specifications for bridge design. A computer program for such optimization method is completed on the basis of the regression analysis and Monte Carlo method. A RC bridge example shows that the optimization based on the utility function describing financial capacity and risk adverse psychology produces the arrangement clearly different from that based on the direct reward.