Progressive Collapse Behavior of a Long-Span Cable-Stayed Bridge Induced by Cable Loss

Driven by high-profile events, much attention has been paid to the progressive collapse behavior of building structures. Comparably less research has addressed bridges, especially long-span cable-stayed bridges. In this paper, the progressive collapse behavior of a prototype long-span cable-stayed bridge is computationally investigated through stay-cable removal analyses. The simulations are carried out by direct sudden removal of a single stay cable at different locations and sequential removal of multiple cables. Dynamic effects as well as material and geometric nonlinearities are accounted for in the simulations, which are used to investigate critical cable loss locations and system response to the various cable loss scenarios. The simulation results show that the prototype bridge exhibits good robustness against failure of a single stay cable. When multiple cables are removed, the bridge is less tolerant to cable losses near its supporting pylons than its midspan. For the former, it exhibits an instability-type partial collapse as opposed to an unzipping type of progressive collapse followed by pylon failure for the latter.