Optimization of concrete cable-stayed bridges under seismic action

Abstract

A computational tool is presented for the optimum design of concrete cable-stayed bridges under seismic action. The finite element method is used for the three-dimensional analysis of the structure under dead and live loads, time-dependent effects and geometrical nonlinearities are considered. The dynamic analysis is solved by the modal/spectral approach. The design problem is posed as a multi-criteria optimization. The design variables are the cable forces and the cross-sectional dimensions of cables, deck and towers. Design objectives of minimum cost, deflections, natural frequencies and stresses considering both, serviceability and ultimate limit states are considered. Given that a gradient-based algorithm is applied for the optimization the discrete direct method is used for sensitivity analysis. An entropy-based algorithm finds economically and structurally efficient solutions by rearranging the stiffness and mass distribution to enhance the structural response. Numerical examples illustrate the features of the proposed computational tool.