Analysis And Research On Monitoring And The Main Girder Stress Of Qiupu River Low Tower Cable-stayed Bridge

Low tower cable-stayed bridge is a new type of bridge betweencontinuous bridge and cable-stayed bridge, it belongs to combined structuresystem which have rigid and flexible characteristics. The past20years sincelow tower cable-stayed bridge emerged, it has developed rapidly at home andabroad because of its many advantages.However its design mainly refer to thetheory of the existing continuous bridge and cable-stayed bridge, besides,thespecial theoretical research on low tower cable-stayed bridge is relatively lessthan others. This paper took construction monitoring on Qiupu River Bridgewhich is under construction as the engineering background, researching thestress mechanism and deformation characteristic of low tower cable-stayedbridge in order to provide a theoretical basis for monitring project andreference for design of similar low tower cable-stayed bridge.First, this paper reviewed the origin,development and research situationat home and abroad of low tower cable-stayed bridge, summarized its systemclassification and mechanics characteristic, and make a brief introduction itsstructural characteristics and applied range.Second, build up the calculation model of Qiupu River Bridge usingfinite element software Midas/Civil, then analyse its stress of girder,especially the structure mechanical behavior at the longest double cantileverconstruction stage and completion state. Result shows that overall mechanicalcharacteristics of Qiupu River low tower cable-stayed Bridge is closer tocontinuous bridge. So its construction control can refers to continuous bridge.Last, do analysis on the section modeling of Qiupu River Bridge withfinite element software ANSYS, and we know that the width and bilateral boxgirder’s normal stress transverse distribution has the regularity of narrowingfrom box girder center to its edges, which is caused by the shear lag effect. Inthe projects implementation, the shear lag effect influence on the stress ofsection should be considered when doing the comparative analysis of stressmonitoring. When designing bridge, it’s also necessary to notice that structuresafety should be ensured by taking some structural measures and the optimizedlayout of the box girder prestress.