State-dependent aftershock resilience analysis of reinforced concrete structures considering the effect of corrosion

Abstract

Numerous aging structures are currently confronted with a seismic crisis due to successive earthquakes. Previous mainshock damage and material deterioration significantly impact the capacity of structures to resist future aftershocks. Conducting resilience analyses, taking into account the current damage state, is crucial to assess the safety of these buildings. In this paper, an analytical methodology is presented for deriving state-dependent resilience curves while considering the coupling effect of corrosion and aftershock. This methodology reforms the structural functionality and introduces a state-dependent resilience function conditional on the mainshock damage state. The aftershock damage data is grouped by the structural response under mainshocks. Then, the state-dependent aftershock fragility and seismic resilience are generated based on the grouped dataset. To demonstrate the proposed methodology, a case study is conducted on a seismic-designed reinforced concrete frame building with varying degrees of corrosion damage. Results show that the proposed methodology effectively evaluates the resilience levels of buildings, considering various mainshock damage states. The mainshock damage significantly influences the aftershock resilience results. A severe mainshock damage can cause a 34 % reduction in seismic resilience compared to an undamaged structure. Furthermore, the reduction in structural resilience caused by the combination of corrosion and aftershock exceeds the sum of the reductions caused by the individual effects of each factor. The findings of this study also emphasize the importance of considering the scenarios involving corrosion and aftershocks when assessing the resilience of structures throughout their service life.