The Analysis Of Long Cantilever Box Girder Of Extradosed Cable-stayed Bridge Girder Space Stress

The extradosed cable-stayed bridge is in continuous beam bridge with traditionalcable-stayed bridge on the basis of the development of a new type of compositestructure bridge, because of its beautiful appearance, economic performance andmaturity of the technology, to be able to develop quickly, especially in the city ofbridges can be a very good application. For this type of bridge main beam under axialpressure, not only, but also bear a considerable part of the bending moment and shearforce, the stress state is complex, the space effect phenomenon is very outstanding.With this kind of bridge span and girder transverse width increasing, the Box GirderCantilever longer, box girder shear lag effect is more obvious. Studies have shownthat, due to the shear lag effect caused by the construction process in some cases boxbeam internal force values than into bridge state force, makes some constructioninternal force to become the design control value.This article take the Chongqing Hechuan Nanping bridge as engineeringbackground, using the MIDAS software to establish the bridge geometry space trussmodel, on the main beam construction process simulation, for the overall stressanalysis of main girder in stages; through the establishment of the whole bridge model,the main beam entity of the overall analysis, the bridge of long cantilever box girderspace stress distribution characteristics. The main research contents are as follows:First, use MIDAS/CIVIL for the bridge in bridge finite element analysis, a briefintroduction to the simulation method, computational analysis of the bridge during theconstruction of the largest cantilever bridge and into the state of the internal condition,summed up space stress distribution characteristics, for the whole bridge local andintegral finite element analysis provide a basis;In second, against the background of engineering bridge, unfolding entity finiteelement simulation analysis, study its construction process in the largest cantilevergirder bridge and into the state of distribution, and the comparative analysis of planelinkage model results, while the tower girder consolidation period of partialanalyses, summarizes the rule of design and construction to provide the related basis;In third, against the background of engineering for the long cantilever box girder of cable-stayed bridge with low towers, will affect the main beam stressdistribution ofsensitivity to several parameters were studied, in order to get reasonable structuralarrangement and economic structure, at the same time as similar bridge researchpreparation.