Experimental and Numerical Study on Failure Modes of UnderDeck CableStayed Simply Supported Bridges

Abstract:

In order to analyze the failure mechanisms, an underdeck cablestayed simply supported model bridge with a span of 10m is tested under the action of increasing midspan load. The failure mechanisms are analyzed by means of both load test and ANSYS finite element analysis. A parameter analysis is performed aiming at the area of cable section, depthspan ratio of strut and section form of the deck. The results show that the failure mode of the model is caused by the fact that the cables break before the deck collapses. According to finite element analysis, when the concrete of the deck enters the plastic state, the flexural rigidity of the deck decreases and the structure efficiency increases. Since the growth rate of the tensioning force of the cables increases under the increasing midspan load, the growth rate of the resistance moment in the deck increases and the growth rate of the load moment decreases. Therefore, the failure mode occurs. The results show that the deck collapses before the cables break by increasing the area of cable section and decreasing the depthspan ratio of strut. The failure mode of the structure with slab deck with a higher slenderness ratio is the same as that of the model, but the maximum midspan load of structure with slab deck is slightly lower than that of the model and its material costs are also lower than that of the model.