Earthquake damage assessment of reinforced concrete wall buildings using inelastic models

Abstract

Reinforced concrete (RC) shear walls are commonly used in seismic environments for lateral building resistance. This type of buildings has shown an adequate performance in past seismic events in general terms. However, a localized damage pattern was observed in recent earthquakes in some shear walls usually located in lower stories of these buildings, characterized by concrete crushing over a short height of the wall and spread almost over its entire wall length. These walls generally had vertical irregularity and lack of transverse reinforcement. This research investigates analytically this damage pattern observed during the 2010 Chile earthquake, and compares different modeling assumptions and the associated uncertainties in these models. A 20-story RC wall building was selected as a case study, and the following building models are presented and discussed: i) two-dimensional models of isolated walls; ii) three-dimensional simplified models of a representative building slice; and iii) three-dimensional models representing the entire building. Different loading patterns and model formulations are presented and discussed, ranging from inelastic finite element models to fiber element models using different software. It was found that high axial stresses played a major role in reproducing the observed damage, and failure was characterized by a sudden loss in strength and stiffness. This failure mechanism was not captured by some of the models, and the key modeling assumptions, such as the effect of induced vertical deformations on the walls, are presented and discussed.