Analytical fragility curve of high-rise reinforced concrete shear wall buildings

Abstract

Chile, as other countries along the Pacific rim, is threatened continuously by various extreme natural phenomena such as the recent earthquakes of the Mw 8.8, Feb-27, 2010 Maule earthquake, the 2014 Mw 8.1, Pisagua earthquake, the 2015 Mw 8.3 Illapel earthquake, and their subsequent tsunamis, which generates comprehensive structural damage in the built environment. After the 2010 Chilean earthquake, close to 2% of the estimated 2000 reinforced concrete (RC) buildings taller than 9 stories suffered substantial damage during this earthquake. Consequently, calculating the probability of RC buildings of exceeding a given damage state during potential future seismic events is of paramount importance. For this purpose the definition of reliable fragility functions for these structures is required. The construction of fragility curves is part of the process of defining the vulnerability of these systems. Herein, analytical fragility curves are built using a numerical model of a 20-story Chilean wall building. First, a model representing an elevation of a prototype RC building is built in OpenSEES to represent the nonlinear seismic response of such building. The prototype building was defined based on the geometry of a real building, and assuming representative characteristics of buildings (i.e. story height, wall thickness, wall density and seismic weight per unit area). For each intensity measure of the earthquake, the seismic variability is propagated using a set of 28 ground motions. The fragility curves obtained in this investigation are intended to be used in damage evaluation and risk assessment studies.