Seismic Performance Assessment of Code-Designed Structures

Keywords: Seismic Performance Assessment, Code-Designed Structures, Shear Wall Structures, Limit State Design,  and Limit State Probabilities.

Abstract: This report presents a method to assess the actual seismic performance of code-designed structures, in particular, shear wall structures. A probabilistic approach is used so that uncertainties in earthquake ground motions, structural responses, and structural capacities can be taken into consideration. Uncertainty in earthquake ground accelerations is explicitly accounted for by generating an ensemble of acceleration time histories from appropriate power spectral density functions and duration of strong motion. The modified Takeda hysteretic model is utilized to describe the nonlinear behavior of structures. The nonlinear seismic analyses are performed to obtain the structural responses, which are then statistically analyzed. The statistics of the structural capacities can also be established based on the defined limit states. The performance of structures is measured in terms of the limit state probability, i.e., the probability that the structural response exceeds the structural capacity. The proposed method may be applied to various types of structures to evaluate the limit state probabilities. Given the limit state probabilities, the authority can consider the societal risk due to the occurrence of earthquakes and make a decision on the appropriate level of earthquake protection.