Shear Lag Effect Analysis Of Curved Thin-walled Variable Cross-section Box-girder Bridge Considering Construction Stage

In this paper, the shear lag effect of box section Bridges at home and abroad research situation and the analysis of the research method to do a detailed review, and the energy method used in thin wall wide variable cross-section continuous beam shear lag analysis of the original formula and deduced in detail, and on this basis, the first step, through the thin wall wide variable cross-section continuous beam theory calculation, web and flange junction parameters on the vertical distribution of shear lag effect, the second step, combining with the actual bridge engineering are humen white huashan bridge, using finite element software of this type of cross section thin-walled box beam wide girder on the calculation and analysis and research on the shear lag effect, and its distribution, the third step, comparing figures of the engineering practice, for its accuracy, this paper compares and analyzes its main content, as shown in the following aspects:(1) Of the shear lag effect of box girder bridge, and the negative shear lag effect of the research background, research significance has been related research status at home and abroad on the mechanics characteristics and the shear lag effect, the research content of this paper lists and research goals.(2) The detailed energy variational method, analogy method, the finite segment method and further clarify the shear lag in box girder bridge girder and the negative shear lag analysis of the mentality.(3) By the energy variational method, using the principle of minimum potential energy the shear lag effect of box section was deduced in detail, and the negative shear lag effect of formulas, and using this formula to an engineering example in variable cross section curve of thin-walled box beam wide under gravity load of the shear lag effect of parameters on the web and flange junction theory value, and then expand the analysis of the distribution regularity and elaboration, it is concluded that within the scope of the theory of shear lag effect and the negative shear lag effect of the largest cross section.(4) Through the establishment of humen bridge engineering instance of Midas Civil bar element finite element model, the curve of variable cross-section thin-walled box beam in wide under gravity load of the key section of the key construction stage are finite element simulation calculation and analysis, get in the shear lag effect and the distribution law; By establishing a finite element model of Midas Fea entity unit, the Midas Civil finite element calculation of the shear lag effect of the largest cross-section of local simulation, it is concluded that the shear lag effect of transverse normal stress stress distribution rule.(5) Combined with stress monitoring data of engineering examples, analyzes the key section of stress and strain values, it is concluded that under the shear lag effect, the transverse normal stress distribution, according to different stage, construction stage and bridge to the shear lag effect of the real bridge, the different construction stages following the distribution regularity of shear lag effect. And the theoretical data and the measured data were analyzed.