Study On The Calculation Method Of Thin-walled Flat Steel Box Girder

Under the commission of the National Natural Science Foundation of China (50608005), the calculational method of thin walled flat steel box girder was studied. As stiffened girder of modern long-span bridges with cable system, the thin-walled flat steel box girder had numerous advantages, such as good torsional stiffness, lateral bending stiffness, excellent wind resistance, etc. Therefore, it has been widely used in long-span cable-stayed bridges, suspension bridges, as well as arch bridges.The author summarized the previous researches, and presented the theory of thin walled bar and general beam theory, as well as elastic thin plate theory, equivalent lattice beam method,and P-E method.On the basis of Hongdao channel bridge of Qingdao bay bridge, spacial pole system finite element model was created to analyse the globle performance of steel box girder. The result showed that the behavior of the bridge was reasonable, the stress in main girder didn't beyond the steel allowable stress.Under the vehicle load, the deformation of main girder was 146.98mm which met the designing requirement.Four models were used to study the influence of diaphragms spacing on top plate.The resulted showed that when the diaphragm spacing was within certain scope, the maximum transverse strain on the top plate decreased with the spacing decreasing. The behavior of diaphragm was studied with the Box girder section model.Stresses in diaphragms were fairly well-distributed on the diaphragm, except the joint areas with other plates.This dissertation also studied the influence of girder height under different support condition on transverse strain of top plate. The result showed the height of girder didn't act obviously effect on the transverse strain. The result of compared analysis showed the pavement acted an important role on the transverse behaviour. Compared with shell finite element model, and the stress superposition method, the mixing finite element model method was sugguested to simulate the performance of the deck.