Lateral Stability of Network Arch Bridges

Abstract

Network arch bridges are arch bridges where hangers intersect each other at least twice. Although these innovative bridges present several advantages in terms of cost and structural performance with respect to the conventional tied-arch bridges, they remain vulnerable under certain loading condition. Indeed, due to the large compressive force that may arise in steel arches of the bridge under service, they are prone to deflect out of his plane resulting in the degradation of the aesthetic aspect often praised of bridges of this type and later its service disablement. For this reason, the lateral behaviour of such kind of bridges should be investigated carefully. In this study, lateral structural response of network arch bridges against traffic loads has been analyzed through extensive non-linear analyses. Firstly, a calibration is useful to validate the numerical model. Then, initial geometric imperfections are assigned to the arch member before the analysis in order to take into consideration defects from the manufacturing process. Finally, non-linear analyses are performed on a full 3D numerical model to capture the behaviour of the arch bridge. The results showed that the lateral displacement of the arch member increase with the increase of the traffic loads up to a certain value. In addition, it is observed that the lateral arch’s bracing changes the development of plastic hinges in the arch.