Structural Response and Reliability Estimates: Slepian Model Approach

This research study investigates the practicality of using a Slepian model to model the earthquake excitation and structural response behavior of structures during the strong ground motion portion and entire duration of earthquake acceleration records. Of particular interest was the extreme response behavior of basic linear and nonlinear hysteretic oscillators. Predictions for the linear oscillators were found to be good, while predictions for the highly nonlinear oscillators were poorer until corrected for the change in equilibrium position experienced during the motion response behavior. Based upon the experience gained from these examples, a three-story frame whose beam-to-column connections were modeled as trilinear hysteretic systems were investigated. The accuracy of the Slepian response prediction for the seismic response was confirmed and the expected value form was coupled with a drift-based limit state function to estimate a conditional form of the first order structural reliability. Since the coefficient of variation of the seismic demand is not explicitly known, the reliability estimates were bounded based upon observations of typical seismic demand variation in engineered structural systems.