Evolutionary design of structural systems with time-variant performance

Abstract

This paper presents an evolutionary approach to the optimal design of structural systems with time-variant performance. The complexity of a multidimensional design is handled by introducing a set of quality indices, which represent the multiple targets of design, and by a systemic vision of the structural model, which can be viewed either as a whole having its own emerging properties, or as composed of elementary parts with their own specific characteristics. An overall measure of lifetime structural quality, able to also take the time-variant structural performance into account, is then obtained through a weighted integration of the quality indices over the expected service life of the structure. In addition, in order to overcome the limits of mathematical optimization methods in solving design problems of high complexity and multidimensionality, the optimal structural morphology is searched for through a two-level heuristic approach based on biologically inspired evolutionary procedures. Finally, the application of the optimal design to a cable-stayed bridge is presented. The results of this evolutionary design process highlight the important role played by suitable measures of structural quality and show that the optimal configurations strongly depend on the time-variant structural performance.