Life-cycle optimization of FRP-strengthening interventions for RC bridge superstructures

This paper presents a systematic method for the optimization of strengthening interventions using fiber reinforced polymer (FRP) for reinforced concrete (RC) bridge superstructures considering two conflicting objectives: life-cycle performance and strengthening cost. The methodology is capable of finding optimal strengthening times for different structural components of an RC bridge superstructure in the form of a Pareto front that can directly facilitate the scheduling and design of FRP-strengthening interventions. Cumulative-time failure probabilities from time-dependent reliability analysis are used as an indicator of life-cycle performance. By virtue of efficient sampling algorithms, cumulative-time failure probabilities can be computed directly during the optimization process. A component-wise bookkeeping technique compatible with parallel computing is employed to further improve computational efficiency. This new method is illustrated using an RC bridge superstructure under chloride-induced corrosion. The proposed method is the first of its kind for optimizing FRPstrengthening interventions for RC bridge superstructures from life-cycle and reliability perspectives.