A Full Process-Evaluation Method for Seismic Resilience of In-Service Reinforced Concrete Frame Structures Considering Corrosion

In the offshore atmospheric environment, reinforced concrete (RC) frame structures face the dual threats of earthquake disasters and reinforcement corrosion induced by chloride ion erosion during service. It is imperative to establish a scientific and reasonable seismic resilience evaluation method to reduce the functional loss during seismic events and shorten the postearthquake recovery time of corroded RC frame structures. In this paper, a multi-index evaluation framework of seismic resilience of buildings, including functional loss, recovery time and repair rate, was first established. Second, considering the shear effect, bond-slip effect, and the influence of corrosion on the material constitutive model, fiber section element and flexural-shear coupled multi-vertical-line-element (SFI-MVLEM) were used to simulate RC beams and columns, respectively, and the accuracy of the proposed model was verified based on the existing seismic performance test data of corroded RC components. Thereby, a numerical model of corroded RC frames was built. Finally, based on the above seismic resilience evaluation method, modeling method, and the corresponding relationship between different service life and rebar corrosion depth under chloride ion erosion, the typical corroded RC frame structure in-service was chosen as a case study to investigate the effects of parameters such as floors number, seismic levels, and service life on the seismic resilience of corroded RC frame structures. Based on the evaluation results, it is found that, with the increase of service life and seismic level, the postearthquake functional loss and repair time of corroded RC frame structures were significantly increased, but the repair rate of the structures had no obvious change. When the service life increased from 0 to 70 years, the median values of functional loss and repair time of the five-floor structure grew by 47.39% and 42.86%, respectively, under a major earthquake. When the service life was 50 years, the median values of the functional loss and repair time of the eight-floor structure increased by 50.94% and 50%, separately when the seismic level changed from major earthquake to mega-earthquake. As the number of floors increased, the repair time of the structure exhibited a significant upward trend, while the repair rate exhibited a downward trend. The research results can provide guidance in the seismic resilience evaluation of offshore urban systems and the achievement of national resilience in urban-rural development goals.