Study On Mechanical Behavior And Design Method Of Skewed Steel Box Girder With Orthotropic Plate

Compared with the orthogonal bridge,the skew bridge has an irregular spatial structure,and its structural response and stress characteristics are more complex,such as the uneven distribution of the reaction force of each support,the phenomenon of bending and torsion coupling,etc.,so the mechanical properties and construction methods of the skew bridge are more complex than the orthogonal bridge.At present,the research on skew bridge at home and abroad has not reached the stage of full application,and there are still many key problems in its analysis and design.Based on the Harbin station reconstruction project — Ji hongqiao cultural relic protection related bridge Ji hongqiao new bridge,the inclined steel box girder bridge under the overall static load,partial wheel load and moving load under the action of the mechanical performance of the theoretical research,the work and the main conclusions are as follows:(1)Midas/Civil software was used to establish the single beam model and girder model respectively,and the counterforce,deformation and internal force calculated by the two models were compared.It was found that the calculation results of the two methods were relatively close,and the girder method was more safe.(2)According to the parametric analysis of the structure,it is found that the slant,the width to span ratio and the layout of the diaphragm have a certain impact on the internal force and displacement of the structure.Due to the influence of slant,the cross-section of skew box girder not only has vertical bending,but also produces torsion.(3)Midas/FEA software was used to establish the local model of slanting box girder bridge plate element,and it was found that the influence of local wheel load on the deformation and stress of the structure was very small,and there was a phenomenon of stress concentration at the connection between u-shaped rib and bridge deck,as well as the connection between diaphragm and bridge deck.In addition,the parameterized analysis of the layout,spacing and thickness of the diaphragm,the inclination and the contact area of the wheel load shows that different influencing factors have influence on the local forces of the skew box girder bridge.(4)The grillage model is built with Midas/Civil software to obtain the natural vibration characteristics of the structure,such as the shape of the vibration,the natural period and the frequency.For structure dynamic response analysis,it found that,with the change of the lane load position,structure displacement change with the time of the same location,the speed of the influence of the maximum dynamic response of the structure is not obvious,when the team through the bridge,the structure of the maximum dynamic displacement than cycling through increased obviously,displacement time history curve fluctuates significantly enhanced.