Detailed Analysis of Arch Foot of a Trough Girder and Arch Composite Bridge with FEA

Abstract

Tied-arch bridges have being widely used in railway for their beautiful shape and rigidity. Current analysis software Midas civil is applied in the overall analysis of many bridges, including the bridge in the article. However, there is huge amount of concrete in the arch foot of the arch bridge, which means that this part cannot be accurately calculated with the model of skeletal structures. Based on the principal of finite element method, Midas FEA plays an important role in the detailed analysis of complicated structure. As a result, it is applied in the local stress analysis of this arch foot. Introduction and Finite Element Division The tied-arch bridge has a span of 120m, whose girder is a trough girder. The height of the channel section at the middle of the span is 2.5m and 3.0m at the support. The arch rib has a shape of dumbbell whose height is 3.0m. Arch foot is a structure of large amount of concrete, in which buried the arch rib with other reinforced steel bar. Longitudinal and lateral pre-stressed tendons also lie in the arch foot, which makes it the most important and complicated part of an arch bridge and can only be analyzed with solid element. In respect of the model in FEA, part of the collar beam right before the first suspender are taken out along with the similar part of arch rib for detailed analysis. Concrete is simulated with solid element and steel plate of the arch rib is simulated with shell element while the lateral tendon is simulated with steel bar element. As longitudinal tendons are continuous in the bridge, they are not simulated in the model.