Seismic fragility relationships of reinforced concrete high-rise buildings

A complete methodology is presented for the seismic fragility assessment of reinforced concrete high-rise buildings. The key steps of the methodology are illustrated through an example of the fragility assessment of an existing 54-story building with a dual core wall system. The set of rigorously derived probabilistic fragilities are the first published for high-rise reinforced concrete buildings. The inelastic nonlinear dynamic analyses for the fragility assessments are made using a simplified lumped-parameter model that was derived from highly detailed FE models using genetic algorithms. New definitions for performance limit states were based on the results of detailed pushover analyses of a distributed inelastic nonlinear finite element model that includes shear-flexure-axial interaction effects. To develop the fragility relationships, 1800 dynamic response history analyses were conducted. This study considered uncertainty in structural material values as well as in seismic demand. Thirty strong motion records were selected for use in the analyses that would produce an appropriate range in structural response characteristics due to variation in magnitude, distance and site condition. The overall approach is generic and can be applied to developing computationally efficient and probabilistically-based seismic fragility relationships for reinforced concrete high-rise buildings of different configurations.