The Study Of Applications On Welding Distortion Prediction And Control Of Long Span Steel Box Girder

Bridge used for railways, highways, pipelines spanning river, valley or otherobstacles is overhead construction. Steel box girder is used in modern bridges widely asthe deck, due to light weight and mass production. This article focuses on the predictionand control of the welding deformation of steel box girder composed of orthotropic plate.Steel box girder is complex structure with a large number of plates and welds. It issignificant to select welding technology and sequence with which the weldingdeformation is as small as possible. This article studies the welding deformation of steelbox girder structure from the following several aspects.First, prediction methods and research status of welding deformation of structure athome and abroad, especially of the large component, is researched. This paper alsoexpounds the concept and applicable condition of each method.Second, this paper analyzes the effects of the parameters of heat source on the weldpool under the condition of considering phase transformation. The influence of the platethickness, the weld spacing, phase transformation and peak temperature on weldingdeformation is studied by thermal elastic plastic finite element method, which can beused as the basis of providing the methods to control welding deformation.Finally, the finite element model of steel box girder is established. The weldingdeformation of steel box girder is predicted using contraction force method. The effectsof welding sequence on welding deformation is obtained. This paper evaluates theflatness of the steel box girder roof after welding in various sequence with MATLAB.Flatness error is used as an index to analyze and evaluate the welding deformation. Thisis a perfect method to obtain a welding sequence quickly, in which the weldingdeformation is relatively small. Finally some methods is put forward to reduce thewelding deformation of steel box girder and orthotropic plate as well.