Optimized Preventive Maintenance Strategies for Corroded Bridge Columns in Earthquake-Prone Regions

Applying preventive maintenance (PM) strategies to corroded concrete bridge columns along their life spans is essential to reduce sudden loss in bridge functionality during earthquakes and associated risk owing to postearthquake damage. This study identifies optimized applications of condition-based PM for bridge columns with an objective to minimize seismic risk and life-cycle cost (LCC) for applying maintenance interventions. External wrapping of columns with fiber-reinforced polymer (FRP) composites and application of cathodic protection (CP) technique were used as maintenance actions. These maintenance actions were applied in four sequence-oriented strategies, namely simultaneous, FRP followed by CP, CP followed by FRP, and FRP only, to explore the benefit of different application sequences involving FRP and CP. Multiobjective optimization using the Nondominated Sorting Genetic Algorithm-II (NSGA-II) was performed for this purpose. Numerical analyses with a model column identified diverse pools of near-optimal solutions with different FRP materials (i.e., carbon and glass), their number of layers, and time of application of FRP and CP. When comparing solutions from different strategies, it was observed that earlier application of FRP was advantageous to keep the expected seismic risk of the column at a lower level for a longer duration of its design life.