International Journal of Bridge Engineering (IJBE), Special Issue 2016, pp. 97-115 *Corresponding Author INFLUENCE OF CABLE FAILURE MECHANISMS ON THE DYNAMIC BEHAVIOR OF CABLE STAYED BRIDGES Domenico Bruno, Fabrizio Greco and Paolo Lonetti* University of Calabria, Dept. of Civil Engineering, Italy e-mail: d.bruno@unical.it, f.greco@unical.it lonetti@unical.it, lonetti@unical.it ABSTRACT: An analysis on the effects produced by failure mechanisms in the cable system is proposed to investigate the behavior of cable-stayed bridges. In particular, the present paper aims to verify the influence on the bridge behavior of accidental breakages produced in the cable system elements also in light of existing design guidelines available from the literature. In the present paper, the numerical model is based on a refined description of the bridge, which involves bridge constituents and external loads. In particular, a geometric nonlinear formulation in which the effects of local vibrations in the stays and large displacements in girder and pylons are taken into account. Moreover, damage effects are simulated by using an accurate description of the release effects produced by the cable-breakage processes. The results denote that several parameters associated with cable-breakage processes, such as the breakage duration, time-transient curve and external load description, are found to influence the dynamic performance of the bridge. KEYWORDS: Cable-stayed bridges; cable-cutting; design guidelines, damage mechanics. 1 INTRODUCTION Stays or hangers are typically employed to create an enhanced structural system able to transfer internal forces between bridge components with lightness, efficiency and reduced costs. In particular, in cable-stayed bridges, the presence of the cables allows the transferring of the forces from the girder to the pylon and facilitates the construction by the cantilever method. However, the cables are typically exposed to several damage mechanisms, such as fatigue processes, corrosion or abrasion, which may cause of a reduction of the cross-section and the strength of the element. As a consequence, the cables are much exposed to failure mechanisms, whose breakage may produce force redistributions and unexpected load configurations. Currently, design guidelines are proposed mainly for cable-stayed bridges, in which specific load combinations concerning dead, live and impact loads are considered. As a matter of fact, PTI