Structural robustness of long-span cable-supported bridges segmented by zipper-stoppers to prevent progressive collapse

This paper investigates the structural behaviour of a long-span cable-supported bridge segmented by zipper-stoppers after the sudden rupture of some of its cables. Increasing the robustness of the structural system through segmentation is a possible approach to prevent progressive collapse in bridges due to cable failure. In this concept, zipper-stoppers, at the segment borders, are strong components with the multiple of the load bearing capacity of usual members and are designed to arrest a zipper-like collapse in the segment where the initial damage occurred. For finding the “stress increase ratio” of the zipper-stopper, an analytical approach based on differential equations of the system will be used. Then, an approximation function for a simplified bridge model in a cable-loss scenario will be derived. The proposed approximation function has been checked by numerical models, and its good accuracy has been proven.