Multidimensional performance limit state for hazard fragility functions

This paper addresses an alternative methodology to calculate fragility functions that considers multiple limit states parameterssuch as combinations of response variables of accelerations and interstory drifts. Limit states are defined using a generalized multidimensional limit states function that allows considering dependencies among limit thresholds modeled as random variables in the calculation of fragility curves that are evaluated as function of the return period. A California hospital is used as example to illustrate the proposed approach for developing fragility curves. The study investigates the sensitivity of the proposed approach for evaluating fragility curves when uncertainties in limit states are considered. Influence of structural and response parameterssuch as stiffnessdampingacceleration and displacement thresholdsground motion inputand uncertainties in structural modelingare also investigated. The proposed approach can be considered as an alternative approach for describing the vulnerable behavior of nonstructural components that are sensitive to multiple parameters such as displacements and accelerations (e.g.partition wallspiping systemsetc.).