Vulnerability and failure analysis of hybrid cable-stayed suspension bridges subjected to damage mechanisms

A numerical model for considering the damage and failure behavior on the cable system is proposed, which can be utilized for obtaining the response of hybrid cable-stayed suspension bridges subjected to moving loads. Damage and failure phenomena on the cable system elements, produced by preexisting corrosion phenomena or unexpected failure mechanisms, are analyzed by using stationary or time dependent explicit laws, developed in the framework of the Continuum Damage Mechanics theory. The bridge analysis is developed by using a refined FE nonlinear geometric formulation, in which the effects of local vibrations on the cable-stayed and suspension systems as well as the influence of large displacements in the girder and the pylons are taken into account. Particular attention is devoted to evaluate the initial configuration under self-weight loads and the corresponding cable dimensioning, which is achieved by solving a constrained optimization problem. Parametric studies are conducted with the purpose of investigating the vulnerability of the structure against damage and complete failure phenomena produced in the cable system by means of comparisons between damaged and undamaged bridge configurations.