Comparative seismic collapse assessment of Chilean code-conforming RC dual wall-frame buildings

Although the satisfactory performance of Chilean buildings in terms of collapse prevention is widely recognized, there is a need to quantify the actual collapse probability and level of protection provided by current seismic codes. In this study, the collapse potential of code-conforming reinforced concrete dual wall-frame buildings subjected to subduction earthquakes was assessed. A suite of four 16-story archetypes, located at two different seismic zones and on two different soil types, was evaluated considering the latest developments in performance-based earthquake engineering through incremental dynamic analyses of 3D nonlinear models. It was found that the probability of collapse in 50 years is in all cases less than the 1% ASCE 7 target probability, which is consistent with the adequate collapse performance of reinforced concrete buildings that has been observed in recent strong earthquakes (Mw ≥ 8.0) in Chile. It was also observed, however, that the collapse probability is not uniform but strongly influenced by the soil type. This observation suggests that the design response spectra indicated by the Chilean seismic design code for buildings might not correctly account for the influence of the soil type.