Multidimensional Fragility of Structures: Formulation and Evaluation

Keywords: Multi-dimensional fragility.  Structural response.  Floor acceleration.  Interstory drift.  Performance limit states.  Probabilistic analyses.  MCEER.  Ground motion.  Fragility curves.  Stiffness.  Acceleration.  Displacement.  Uncertainty.  Parametric analyses.  Maximum likelihood method (MLE).  Seismic performance.  MCEER West Coast Demonstration Hospital.

Abstract: This study investigates the sensitivity of fragility curves when uncertainties in limit states are considered.  Using the MCEER west coast demonstration hospital in the San Fernando Valley in Southern California, influence of structural and response parameters, such as stiffness, acceleration and displacement thresholds, input ground motion, and uncertainties due to structural modeling, are investigated.  Different structural parameters that drastically affect fragility are considered.  A generalized formula for multidimensional threshold limit states is proposed, and various cases are considered to illustrate the formulation.  References, illustrations and tables are included.