Performance-based earthquake engineering using structural optimisation tools

A Performance-Based Design (PBD) procedure for steel structures using structural optimisation is presented. The structural performance is evaluated by means of the reliability demand and resistance methodology of US FEMA-350 guidelines where the uncertainties and randomness in capacity and seismic demand are taken into account in a consistent manner. Both non-linear static and non-linear dynamic analysis procedures are used to obtain the response at two hazard levels. The design procedure is performed in a structural optimisation environment, where the Evolution Strategies (ES) algorithm is implemented for the solution of the optimisation problem. To handle the excessive computational cost, the inelastic time history analyses are performed in a parallel computing environment. The objective of this study is to obtain the design with the least material weight, and thus with less cost, that is able to respond with the desired confidence for each performance level following the specifications of FEMA-350.