Effect of loading pattern and deck configuration on the progressive collapse response of cable-stayed bridges

In the cable stayed-bridges, sudden loss of cables is usually associated with material as well as geometrical non-linearities that may trigger progressive collapse of the entire bridge. Accordingly, in this paper detailed 3D finite element models of a hypothetical cable-stayed bridge is developed and analysed with material and geometrical non-linearities included. A parametric study is undertaken and effect of cable loss scenarios (symmetric and unsymmetric), deck configurations (steel box girder and open orthotropic deck) and number of lost cables on the progressive collapse response of the bridge is investigated. With regard to the results of parametric study, it is concluded that the deck configuration has a minor influence on the progressive collapse response of cable-stayed bridges. Also, it is shown that localised yielding of steel may occur following loss of more than one cable, however, such localised plastic strains cannot trigger the progressive collapse of the entire bridge. During cable loss scenarios, the reduction in post-tensioning stress and subsequently stiffness of the remaining cables (reflected in Ernst’s modulus) is found to be around 10% that warrants effect of geometrical non-linearities within the cables being considered.