Analysis of the seismic capacity of Chilean residential RC shear wall buildings

Abstract

A very low percentage of reinforced concrete buildings subjected to the 2010 Chile earthquake suffered severe damage, even though they were affected by ground accelerations significantly larger than those prescribed by the Chilean seismic design code. This observation suggests that the seismic capacity of such buildings is actually much larger than that required by the seismic design code. In order to obtain insight into this issue, three actual building structures (of 5, 17 and 26 stories) that withstood the 2010 Chile earthquake with no observable damage are analyzed. A linear elastic concrete material model is adopted. In a first series of analyses, nominal procedures are used to calculate seismic demands and member capacities. In a second series of analyses, seismic demands are calculated by performing response history analysis, and member capacities are evaluated by state-of-the-art procedures. Results from nominal analyses are not consistent with the observed lack of damage in the 17- and 26-story buildings. Results from response history analysis are indeed consistent, but only when foundation uplift is accounted for. The suitability of linear concrete material models to assess the response of apparently undamaged reinforced concrete shear wall structures subjected to strong seismic demands is then discussed.