Analysis Of Single Box3Rooms And Variable Cross Section Continuous Girder Bridge’s Spatial Stress

This article, firstly, introduced the section features and mechanicalcharacteristics of box section, illustrated the concepts of shear lag effect andanalyzed the shear lag effect of box section by putting forward to calculate theshear lag effect coefficient. After providing information of several mainstreammethods to analyze shear lag effect, this paper aimed to finding out the solution ofthe longitudinal normal stress of continuous girder bridges of variable cross sectionwith single box and three booths under the consideration of shear lag effect, bychoosing the energy-variational method based on the principle of minimumpotential energy. The predecessors used the energy-variational method to solve theshear lag effect problems of the constant cross section box girder with single boxand three booths. Based on this foundation, this article derived the stress formulasby means of adding longitudinal displacement functions, deriving the governingdifferential equations of cross section with single box and three booths. Which hasbeen substituted some specific boundry conditions into it. Also, several commonsolutions of solving continuous girder has been present in this paper, especially thesuperposition method. An example is furnished to explain it in detail. The approachof Quanhe Bridge was taken as an example. This thesis created the beam unit spacebar FEM model with MIDAS CIVIL, and whole procedure has been divided intodifferent construction phase, so that every construction phase of the whole bridgeand the completed bridge state could be solid modelered through the analyzing ofnumberical model. Then the stress value of the typical section under maximumdouble-arm and continuous girder bridge can be derived, while the shear lag effectis taken into consideration. All the stress data are collected and compared to make alongitudinal map showing the shear lag effect coefficient. The map would reflectthe direct link between the shear lag effect and the factors such as girder-heightratio, width-length ratio. Loading arrangement and other conditions. Besides, thisdissertation is modeling and analyzing of FEA about lateral influence factorslongitudinal stretch. At the end of this paper, some regular conclusion aresummed up after identifying P-and-S-wave, transverse prestress and diaphragmplate, while compared with the basic model.