Seismic capacity evaluation of corroded reinforced concrete frame structures

In-service reinforced concrete (RC) structures trigger complex deterioration mechanisms in seismic performance due to corrosion, leading to difficulties in evaluating the seismic capacity. To scientifically evaluate the seismic capacity of corroded RC frame structures, this paper proposes a quantifiable framework for absolute seismic capacity evaluation. The study establishes numerical models of typical RC frame structures considering the number of stories, service years, seismic fortification intensity, and different versions of design codes. Additionally, classification criteria for structural failure states based on the proportion of component damage are proposed. The seismic capacity of corroded RC frame structures under different failure states is determined using elastoplastic time-history analysis, and the influence of various parameters on the structural seismic capacity is investigated. Based on the results of the structural seismic capacity evaluation, a prediction model for the seismic capacity of corroded RC frame structures is developed using the BP neural network to establish the nonlinear mapping relationship between key parameters and structural seismic capacity. The results indicate that the seismic capacity of corroded RC frame structures continuously decreases with an increase in the service years and the number of stories. Earlier versions of design codes result in smaller residual seismic capacity of RC frame structures under different failure states, with a faster degradation rate. The sensitivity of the structural seismic capacity to various parameters is ranked as follows: structural failure states, the number of stories, seismic fortification intensity, service years, and versions of design codes.