SEISMIC FRAGILITY AND COST ANALYSES OF ACTIVELY CONTROLLED STRUCTURES
Kevin K. Wong, John L. Harris
Seismic fragility represents the probability that the structural response exceeds a given performance limit state due to a specified intensity of ground motion, and it has a direct relationship with the cost of rehabilitating the structural system. In this research, a cost analysis framework based on seismic fragility to quantify the expected loss of the structural system is proposed. Incremental dynamic analysis is used to generate the fragility curves, and plastic strain derived from plastic energy dissipation is used to quantify the structural damage at local levels. Two moment-resisting steel frames and 100 non-stationary Gaussian earthquake ground motions are simulated, and correlations between local damage states and global performance limit states are performed to facilitate the cost analysis study. Results show that good correlations exist in seismic fragilities and therefore the repair cost of the structural system becomes quantifiable. Active control based on the optimal linear control algorithm is included in the study to identify the sensitivity of the correlations. It is observed that significant cost reduction can be achieved for low-rise structures when active control is used, but may not be cost effective if it is installed in taller structures.
The Structural Design of Tall and Special Buildings