Multi-criteria Optimal Structural Design under Uncertainty

A general framework for multi-criteria optimal design is presented which is well suited for performancebased design of structural systems operating in an uncertain dynamic environment. A decision theoretic approach is used which is based on aggregation of preference functions for the multiple, possibly con#icting, design criteria. This allows the designer to trade o! these criteria in a controlled manner during the optimization. Reliability-based design criteria are used to maintain user-speci"ed levels of structural safety by properly taking into account the uncertainties in the modelling and seismic loads that a structure may experience during its lifetime. Code-based requirements are also easily incorporated into this optimal design process. The methodology is demonstrated with a simple example involving the design of a three-storey steel-frame building for which the ground motion uncertainty is characterized by a probabilistic response spectrum which is developed from available attenuation formulas and seismic hazard models. Copyright ( 1999 John Wiley & Sons, Ltd.