Research On Composition Section Of Steel-concrete Hybrid Girder Cable-stayed Bridge Of Finite Element Calculation Key Technology

Steel-concrete hybride girder as one of structure usually applied to girder of longspan cable-stayed bridge.And the structure of steel-concret composited beam is setting link joint construction in concrete side span and steel box girder main span.Compared with only using concrete or steel,Steel-concrete hybride girder have higher strength and stiffness body,as well as lower prices.Because the complex of the hybride sectionis structure and the complicated of interaction mechanism between concrete and steel,which could be caused inaccurate results from tectonic joint site simplification and finite element calculation.Furthermore,it can leads to large amount of calculation should be done.This thesis,based on the example of Gaojiaogarden bridge,using MIDAS series software,which has conducted the following research:(1)The finite element model of the whole bridge is established to analyze the internal force,stress and displacement of the full length main beam under the combined load of the bridge.According to the distribution of stress and displacement,as well as Saint venant principle,it can define the capture range and simplified boundary conditions of beam model.(2)Based on the power transmission way of steel-concrete mixed section,it study the fine structure model with shear studs and conode model without shear studs The calculated results of the same load condition are shown by comparison: In the same consideration of which concrete completely adhere to the pressure plate and the PBL bond key.The contact relationship between the two materials is treated as a common node.It proves that the results of the simplified model and the results of the elaboration model were calculated to be within the scope of the deviation,as well as stress and displacement of mixed section have a smooth transition.Therefore,the analysis accuracy of the simplified structure of the main beam is not affected.(3)It establishes main beam finite element models with entity unit,entity-plate combination unit and beam unit respectively,researching the stress characteristics of the combined segments of the various models in the combination of non-reinforcing bars,prestressed reinforcement and all-reinforcement bars.And it concludes that the calculation results of the prestressed model and full reinforcement model are very close,and the non-reinforcement model's results have a numerical difference.Compared with the finely divided entity unit,the concrete entity-plate combination unit combined the calculation result with the basic match,and the results of the unit model stress and displacement calculation can envelop the entity unit model which is more safety.It is also superior to the entity model in modeling computation effort.So,It is recommended to use the combination of entity and board units to simulate steel concrete composite girder cable-stayed bridge.