Multi-criteria optimal structural design under uncertainty

A general framework for multi-criteria optimal design is presented which is well suited for performance-based design of structural systems operating i n an uncertain dynamic environment. A decision theoretic approach is used w hich is based on aggregation of preference functions for the multiple, poss ibly conflicting, design criteria. This allows the designer to trade off th ese criteria in a controlled manner during the optimization. Reliability-ba sed design criteria are used to maintain user-specified levels of structura l safety by properly taking into account the uncertainties in the modelling and seismic loads that a structure may experience during its lifetime. Cod e-based requirements are also easily incorporated into this optimal design process. The methodology is demonstrated with a simple example involving th e 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. C opyright (C) 1999 John Wiley & Sons, Ltd.