An investigation on the structural integrity of network arch bridges subjected to cable loss under the action of moving loads

A numerical study is developed to investigate the structural behavior of network arch bridges subjected to the cable loss of hanger elements of the cable system under the action of moving loads. The main aim of the paper is to analyze the effects produced by potential cable loss scenarios on the main kinematic design variables of the structure. The structural behavior is investigated by means of a refined FE nonlinear geometric formulation, in which the influence of large displacements and local vibrations of cable elements are taken into account. The loss of a cable is properly reproduced by means of a damage law consistently with Continuum Damage Mechanics theory. Moreover, a refined formulation is implemented with the aim to reproduce the inertial characteristics of the moving loads, by accounting for the coupling effects arising from the interaction between bridge deformations and moving system parameters. Numerical analyses are performed by means of both nonlinear dynamic analyses and simplified methodologies proposed by existing codes on cable supported bridges. In this framework, the applicability of such simplified methodologies in the case of the network arch bridges is discussed.