EFFECTS OF MODELLING UNCERTAINTY ON PROBABILISTIC BUILDING RESPONSE ANALYSIS

A primary step in evaluating a building at different performance levels is to estimate the response of the building to future earthquake ground motions. A procedure is presented to calculate the probabilistic seismic response of buildings. The proposed procedure is quite generic and can be used for any type of structural response parameter. The effects of changes in modeling assumptions on the estimation of the seismic response of reinforced concrete buildings subjected to earthquake ground motions are examined. Three different models of a seven-story moment resisting frame building are developed. For each model different assumptions of the strength and stiffness of structural elements that are commonly used have been adopted. The effects of these modeling assumptions on the probability distribution of various response parameters, namely interstory drift ratio and floor acceleration, conditioned to the ground motion intensity are evaluated. Preliminary results suggest that, the annual rate of exceedance of specific response parameters can exhibit significant variations with changes in modeling assumptions, since the ground motion hazard intensity on the building is a function of the lateral strength and stiffness of the structure.