The Influence On Multi Span Cable-stayed Bridge Girder By Changing The Local Structure Parameters

With the development of modern new material technology and construction technology, the span of the bridge has obtained the breakthrough development, as a result of the need of sea-crossing and river-crossing, more and more long bridge was put into operation. Multi span cable-stayed bridges is one of the large span bridge type, in recent years, it is widely used and developed in the construction of high-grade highway in our country. So engineers and scholars at home and abroad has carried on seriously and systematically study on multi span cable-stayed bridges, and put forward the concept of analysis from different angles in multi span cable-stayed bridges. Because of the huge difference between each across of multi span cable-stayed bridges, and there are certain deviations of local structural parameters when the bridges under construction or operating. But how much influence on multi span cable-stayed bridges when the local structure parameters change, and can make the structure more reasonable in term of stress and deformation, we still have no idea. So this paper will make a parameter’s analysis on the local structure of multi span cable-stayed bridges depends on numerical modeling, and will analyze girder’s deformation and stress under the action of dead load and live load, and will analyze stability and dynamic property of the structure. Then we can conclude the sensitivity for each parameters on girder’s stress and deformation.This paper takes ChiShi Bridge as engineering background, and analyze the influence on bridge by local structure parameters, mainly includes the following contents:(1) Through the literature, we review the development、structural characteristics and research progress of multi span cable-stayed bridges, then we Raise the research contents in this paper. We also deduce some formulations including girder’s deformation and bending moment under the load of live and dead, structure’s stability and natural frequency of vibration.(2) In the aspect of numerical simulation, this paper using MIDAS/CIVIL to make a simulated analysis on structure, chooses four parameters including the main tower stiffness、the stay-cables stiffness 、 inclination of the stay-cables and the stay-cables spacing of cable-stayed bridge to analyze, compares the influence of different areas by the four parameters. Then we choose an area that has bigger influence on girder to have a detailed study.(3)We will make a more detailed analysis on the four parameters by using simple variable method, to study the influence on the girder by the four parameters. Date shows that multi span cable-stayed bridges on the sensitivity of the different parameters are different, and present different regularity.(4)This paper will give some good advises on multi span cable-stayed bridges.