Scheme Design Of Wenling Yuejin Bridge And Research On The Optimization Of The Structure

Along with development of economy, the traffic pressure increases very quickly. In order to meet the need about traffic, the widths of urban roads are much broader than before. As a result, the width-span ratios of some bridges even exceed one. At the same time, citizens raise higher aesthetics requirements to urban bridges which are regarded as a part of public buildings. Compared to cable-stayed bridges, suspension bridges, arch bridges are often selected in scheme design as they can be built with various shapes with unique aesthetic value and lower costs.The paper is based on Yuejin Bridge reconstruction project, the main work of the paper is about the scheme design and optimization design of a concrete-filled steel tube arch bridge, which is selected in scheme design. The optimization design is based on finite element software Midas Civil 2013.Firstly it discusses the differences between the substructure excluded model and the substructure included model, the influences of the m-value based on the substructure included model, the effective width for elastic shear lag according to different standards by calculate. Secondly, it discusses the impacts of different factors such as the stiffness of the steel box girder, the wall-thickness of the steel tube, the preliminary tension of the suspender and the minor arch by the substructure included model, on force and deformation in the structure. Besides, the influence of the wall-thickness of the steel tube and the inclination of the main arch on both elastic buckling and dynamic characteristics are also studied.Analysis results show that the substructure excluded model can be only used in preliminary design with the purpose of saving time and the substructure included model is suitable for construction drawing design, it is much safer to calculate the effective width for elastic shear lag of Yuejin Bridge by European Standard than Chinese Standard. In addition, the minor arch makes great contribution to the stability of the CFST Bridge, meanwhile the preliminary tension of minor arch affects the thrust force of skewback, the displacement of top of the pile and the lateral displacement of the arch, thus the minor arch is the key component, and a sufficient safety degree is proposed. Besides, it is concluded that the force and the deformation are great influenced by the stiffness of the steel box girder, the wall-thickness of the steel tube and the suspender. Both the wall-thickness of the steel tube and the inclination of the main arch have a great influence on elastic buckling and dynamic characteristics.The static and dynamic analysis for CFST Bridge whose width-span ratio is close to 1 has been realized by the existing finite element software. The research result provides reference for construction drawing design and has reference value for this type of arch bridges.