Consideration of economic vulnerability in seismic performance evaluation of structures

Abstract

Risk (economic, social and environmental) assessment and mitigation have recently gained great attention. It refers to computing the risk of a community's infrastructure associated with natural hazards such as earthquakes, landslides, hurricanes or others. Performance evaluation of structures has until now been based on evaluation of maximum displacements, interstory drifts, deformation patterns, ductility and other similar parameters; a relative economic loss estimation as a performance measure for the structure is the next step that follows, and is what has been investigated in this work. For this study a steel mid-rise structure was designed according to code provisions (ASCE 7-10, NSR-10, AISC-341) using modal spectral analysis, after which it was subjected to an Incremental Dynamic Analysis procedure to evaluate the capacity curve of the building. The capacity analysis was then used to determine damage states and compute fragility curves. Finally, economic relative loss values were assigned to represent each designated damage state, for which the mean damage ratio was computed (in terms of economic loss relative to total replacement cost) as a function of spectral displacement. Assigning a relative loss index to damage states is the critical stage of the analysis.