A Mechanical Characteristics Study On Urban Steel Arch Bridges With The Asymmetric Tilt Arch

With the development of the economy, modern aesthetics is required. Therefore, urban steel arch bridges with the asymmetric tilt arch develops rapidly in recent years. This research work was based on the project of Road Sixteen Nanming Bridge in Guiyang, Guizhou province, studied the mechanical characteristics of the bridge. Meanwhile, suggestion of design optimization about this kind of bridge was offered.First of all, the history of urban steel arch bridges with the asymmetric tilt arch, its forced features and latest research progress was mentioned. The Spatial finite element model of Road Sixteen Nanming Bridge was built using Midas/Civil, illustrating the global stress and deformation characteristic under different loading combination during construction and operation stages.Secondly, the method to determine tensioning force of hangers in the construction was discussed; afterwards, the method to calculate the control force in the construction for hanger tension and force adjustment was obtained. By comparing the effect of different tension sequence on force of hangers, arch stress, vault displacement and steel box girder displacement, the optimal design was presented. A construction-friendly controlling method of camber was given.Thirdly, the structure stability in different construction stages and how it was influenced by rise-span ratio, camber angle, compressional stiffness, in-plane bending stiffness and out-plane bending stiffness of arch rib was studied on the basis of the stability analysis model using Midas/Civil. At the same time, the optimal stability design method was demonstrated by comparing the effect of different tension sequence of hangers and arrangement form of live load on the structure stability coefficient.Finally, local analysis model of half bridge was built using Ansys software. Based on this, the stress characteristic of arch springing and the position on which stress concentration mostly occurred was discussed. Meanwhile, the principle of bolt groups on arch springing was introduced. Then two kinds of simplified model to calculate the bolt groups was built using Midas/Civil and Ansys, considering the simplified analytical approach provide by the code. Finally, the effective method about bolt groups simplified calculation was shown by calculating and comparing, which could be a design reference for similar designs.