UCLA

The goal of this project was to develop Matlab scripts which can be made available publicly for analyzing the probability of damage of structural components in a tall building following an earthquake. The procedure involved using results from 75 ground motions from the PEER task 12 report run in a Perform-3D model obtained from the building designer to define fragility curves for coupling beam rotation and core wall curvature in an existing reinforced concrete core wall building in downtown Los Angeles. The codes written for this project are intended for modification for any similar building, and also can be modified to analyze other structure types.

The first challenge was to develop an intensity measure that depended on the building response to serve as the independent variable for defining the fragility curves. The intensity measure developed uses a combination of spectral drift for the first 11 modes at each ground motion intensity and can be generalized for any building. Next, the damage states were defined using models from recent research in coupling beam and wall curvature deformation behavior. The fragility curves developed are irregular due to the non-linear behavior of the building, where increasing earthquake intensity is not directly correlated with increasing probability of exceedance. Consequently, the fragility risk of each component needs to be individually evaluated by the structural engineer to determine where inspection efforts should be focused.