Improved hanger design for robustness of through-arch bridges

Hangers in through-arch bridges are important components since they suspend the entire bridge deck from the arch ribs. Local damage at a hanger may lead to subsequent damage of various components in the vicinity or even progressive collapse of the bridge. After reviewing the conventional design of double-hangers in through-arch bridges, this paper puts forward a new design approach. The suitability and robustness of this new approach are then verified by numerical simulation of a real bridge. The impact effects induced by local fracture of a hanger on the other structural members are then simulated by dynamic time–history analyses. The new approach of hanger design is shown to improve the structural robustness. In particular, when one or more hangers are damaged thereby causing local failure, the through-arch bridge will not be endangered and will still maintain reasonable overall load-carrying capacity so that the necessary emergency measures can be taken.