Seismic fragility assessment for reinforced concrete high-rise buildings in Southern Euro-Mediterranean zone

This paper presents seismic fragility assessment of RC high rise-buildings for seismic excitation, typical for Southern Euro-Mediterranean zone. The fragility curves were derived and log-normal cumulative distribution function parameters were obtained for the four defined damage states by conducting 3600 nonlinear time-history analyses on the basis of 60 ground motions with wide range of magnitudes, distance to source and different site conditions, including in this way uncertainties during ground motion selection. As a prototype buildings, 20-story, 30-story and 40-story RC high-rise buildings with core wall structural system were chosen. The key points of the process for obtaining the fragility curves are shown by using algorithm, defined in this paper, and generally applicable to all types of RC high-rise buildings. For the purpose of conducting nonlinear time-history analyses, non-linear 3D models of the buildings were designed. A detailed probabilistic seismic damage analysis was done and as its result the limit states as well as corresponding damage states for RC high-rise buildings were defined, where the damage states were treated as random variables. Inter-storey drifts at threshold of damage state were defined as random variables with the range of possible values. Since no probabilistic fragility curves exist for this class of buildings and for this seismic zone, this work partially fills the void in Southern Euro-Mediterranean seismic risk assessment. The whole approach presented in this paper may be used for efficient obtaining probabilistic fragility curves for RC high-rise buildings of different configurations.