Seismic performance-based design and an application to a pile foundation

An approach for performance-based design in earthquake engineering is presented. The method involves an optimized solution for design parameters to approximately meet target reliabilities for different limit states or performance requirements. Structural response statistics (mean and standard deviations) are obtained over a set of earthquake records. Databases for these statistics are developed a-priori in terms of the other intervening variables, and then represented by corresponding neural networks. These networks, in turn, are used to estimate reliability by simulation and to implement the optimization. The design of a steel pile carrying a mass M is shown as an example. The response is obtained by a dynamic, non-linear finite element analysis and, therefore, the calculated hysteresis adapts to any input earthquake record. Comparisons are shown when the same problem is analyzed by a BWBN hysteretic model fitted to the response of the pile to a specific cyclic cap displacement history.