Development of earthquake vulnerability functions for tall buildings

摘要

This study focuses on the development of vulnerability functions for tall buildings. A systematic simulation approach based on the Pacific Earthquake Engineering Research loss assessment framework is used to develop building vulnerability functions that provide estimates of losses to buildings under ground motions of various intensities. The steps involved in the procedure are: quantifying ground-motion hazard using a vector of spectral accelerations; predicting building response parameters such as story drifts, floor accelerations, and residual drifts under the quantified hazard; accounting for structural collapse and demolition; and predicting story-wise losses and total building loss using the building response information. Emphasis is placed on capturing the effects of epistemic and aleatory uncertainties in random variables, such as ground motions, structural response parameters, loss costs, etc., to quantify the uncertainty in the final loss estimate. The risk assessment approach is used for developing vulnerability functions for six tall buildings, namely, 20-story and 40-story steel moment resisting frame buildings based on 1973 and 2006 codes, a 42-story concrete core wall building and a 42-story concrete dual system building. The vulnerability functions are used to perform loss assessments for individual buildings assumed to be located in Los Angeles. The vulnerability and the loss assessment procedures are illustrated in detail for the 2006 20-story steel moment frame building, and a summary of the final loss estimates are provided for all other buildings. It is seen that epistemic uncertainties in both ground motion hazard and building vulnerability cause significant epistemic uncertainties in the loss assessment results.