University of California Transportation Center

This paper presents a reliability-based optimization model of inspection, maintenance, and replacement for a system of several highway bridges. The objective in the formulation is to minimize the total expected social cost, including the expected cost of failure. The frequency of inspections is included as a decision variable. The probability of failure is explicitly taken into account in the constraints. A bottom-up approach is used, which allows for bridge-specific details to be taken into account. Most existing system level models assume that component deterioration is memoryless; however, this assumption is relaxed in this paper, and history-dependent deterioration models are used. The formulation is flexible enough to accommodate different types of facilities, deterioration processes, and failure modes. A parametric study is conducted to demonstrate the model’s response to different assumptions on the deterioration rates, and maintenance costs and efficiency.