STRUCTURAL RELIABILITY-BASED LIFE-CYCLE COST OPTIMIZATION OF MAINTENANCE INTERVENTIONS FOR DETERIORATING BRIDGES

The assessment of the current state and the prediction of the future condition of the deteriorating structures are crucial issues for bridge management. Time-varying loads, deteriorating resistance, as well as maintenance interventions for the sake of safety and serviceability, make the prediction very difficult. In order to perform a realistic life-cycle performance analysis of deteriorating bridge under different maintenance scenarios, the uncertainties involved have to be considered. Based on the improved deterioration model, a set of calculation formulas for reliability index under different maintenance strategies are proposed in this paper, and calculation methods for indirect maintenance cost in service time are presented. By minimizing the present value of life-cycle cost, the maintenance strategies are identified, which best balance cost and reliability index profiles over a specified time horizon under constraint of structural life-cycle performance and fiscal budget. Finally, the proposed method is applied to a deteriorating bridge surface to demonstrate its feasibility.