Time-dependent vulnerability assessment of RC buildings considering SSI and aging effects

Abstract

The present study aims at the assessment of the seismic vulnerability of reinforced concrete (RC) buildings taking into account the soil-structure- interaction (SSI) and the aging effects due to reinforcement corrosion. Two-dimensional non-linear dynamic analyses are performed to assess the seismic performance of initial (t=0 years) and 50 years old RC frame structures. Soil-structure interaction is modeled by applying the two most commonly used approaches, i.e. the substructure and the direct method, to allow for direct comparison. Chloride induced corrosion is taken into account based on probabilistic modeling of corrosion initiation time and corrosion rate. The time-dependent fragility functions are derived for predefined damage states at different time periods in terms of outcrop peak ground acceleration. The results indicate an increase of seismic vulnerability over time due to aging effects (corrosion). An overall increase in structure's fragility is also observed when considering the soil deformability and SSI. Moreover, the comparison between the two methods of SSI modeling (sub-structuring and direct) indicates the conservativeness of the sub-structuring over the direct method with the former predicting higher vulnerability compared to the later.