Seismic Response Prediction of Self-Centering, Concentrically-Braced Frames Using Genetic Programming

Conventional concentrically braced frame (CBF) systems are commonly used in earthquake-resistant structural systems. However, they have limited drift capacity before brace buckling occurs. Self-centering, concentrically-braced frame (SC-CBF) systems have recently been developed to increase drift capacity prior to initiation of damage and to minimize residual drift. SC-CBFs have more complex behavior than conventional CBFs. The seismic response of SC-CBFs depends on many new parameters such as rocking behavior, post-tensioning bars, and energy dissipation elements. Additionally, uncertainty of mechanical properties (e.g., coefficient of friction in the friction-bearings) can affect the system response. To design SC-CBF systems, an accurate prediction of the statistical parameters of roof drift demand is essential. In this study, genetic programming is used to predict the mean and standard deviation of SC-CBF peak roof drift response under the design basis earthquake using the most effective mechanical and geometric parameters. The results of this study can then be used in the future to design more efficient SC-CBF systems with a more accurate roof drift prediction.