Seismic fragility assessment for reinforced concrete high -rise buildings.

摘要

This is a comprehensive study of seismic fragility assessment by the graduate student at the University of Illinois who is in the very final stage of completing his doctoral degree. As part of the Mid-America Earthquake Center Engineering Engine project, this research aims at deriving probabilistic assessment procedures for seismic fragilities of reinforced concrete high-rise buildings.;A complete methodology is proposed and demonstrated, containing the key steps of the methodology and the illustration through an example of the fragility assessment of an existing 54-storey building with a dual core wall system. The set of rigorously derived probabilistic fragilities are the first published for high-rise RC buildings, thus they fill an important void in regional earthquake impact assessment in Metropolitan communities. The inelastic dynamic analyses for the fragility assessments are undertaken using a simplified lumped-parameter model that was derived from highly detailed FE models using genetic algorithms. New definitions for performance limit states are based on the results of detailed pushover analyses of a multi-resolution distributed finite element model that includes shear-flexure-axial interaction effects. To develop the fragility relationships, more than two thousand dynamic response history analyses were conducted. This study considered uncertainty in structural material values as well as in seismic demand. Thirty natural and twenty artificial strong motion records were selected for the analyses that would produce an appropriate range in structural response parameters due to variation in magnitude, distance and site condition. The overall approach is generic and can be applied to develop computationally efficient and probabilistically based seismic fragility relationships for RC high-rise buildings of different configurations.