Optimal design of tapered steel-concrete composite bridges / Analisi e ottimizzazione di ponti in struttura mista acciaio-calcestruzzo con travi di altezza variabile

In the design of composite multi-girder bridges, structural optimization, aimed at the reduction of construction material while guaranteeing safety during the whole service life, is becoming the key phase of the design process. Due to the large number of variables involved, optimization in infrastructural works has been often carried out by a manual iterative process in which the structure is updated following observations from preliminary projects. In this paper an automated procedure for optimizing composite bridges with tapered girders using genetic algorithms is presented. The work starts with preliminary parametric analyses on composite tapered beams and then the outcomes are used for setting up the programs involved in the optimization: AutoBiD and T.O.S.C.A., both C#-code programs developed at the Architecture and Engineering Department of University of Trieste. Finally, the results of the application of the proposed approach to the geometry of some real bridges are presented.