Performance-Based Design Optimization of Corroded Special Moment–Resisting RC Frames

A new optimized performance-based design procedure is presented for two dimensional (2D) reinforced concrete (RC) special moment-resisting frames by considering a probable corrosion damaged level. In this way, three 2D RC moment resisting frames with three, six, and nine stories are considered in the performance-based design procedure. Three probable corrosion damaged levels, including 6%, 12%, and 18% (mass loss of longitudinal reinforcement), are considered in the design procedure as uniform corrosion on all elements of each frame. Genetic algorithm (GA) and particle swarm optimization (PSO) are two methods that are mixed to optimize the results. The cost of materials including concrete and steel reinforcement is the objective function of the optimization problem. The dimensions of beam and column sections and the reinforcement ratio are design variables; the performance level of frames and serviceability are considered constraints of the problem. Nonlinear static analysis (NSA) for a specific hazard level is applied for the analysis during the design procedure. Seismic fragility curves are extracted for designed frames to assess the probability of failure. The results indicate that considering probable corrosion damage in the design procedure resulted in a higher cost of materials but could significantly reduce the probability of failure for a specific hazard level.