Seismic Fragility Assessment for Steel Buildings with Different Performance Levels

Abstract

The probability of failure associated with drift criterion exceeding certain performance levels for the intensity of earthquake record ground motions has been necessitated for the development of fragility curves in the recent past as a better performance check tool. In the recent past, the reappraisal of fragility curves formation due to incremental dynamic analysis has been possible because of modeling and simulation of structures under varying earthquake ground motions. The content of this paper is the formation of fragility curves using drift as the output of steel building frames under varying earthquake ground motions. The fragility curves were developed through nonlinear time-history analysis assessments of selected ground vibrations with varying magnitudes, distances from the source, and site circumstances. The entire process given in this paper can be utilized to develop probabilistic fragility curves for structural buildings of various layouts. As an illustration, fragility curves for two steel building structures for various performance levels: Collapse prevention (CP), Life Safety (LS), Immediate occupancy IO), & operational performance (OP), were developed using Ram Perform 3D, using a set of 20 earthquake ground motions. The fragility curves formed using drift for different performance levels reveal a robust damage index for evaluating building structures under the high level of seismic hazards.