Torsion And Distortion Behavior’s Analysis Of The Rail Continuous Beam Of Han Jiang Bridge

Multicell box girders, which have excellent structure and mechanical performance, for example higher flexural capacity and torsion rigidity, are used extensively in the construction of urban highway, horizontally curved, and long-span bridges. But it is complicated to analyze torsion and distortion of multicell box girders under eccentric loads. Along with the extensive use of multicell box girders in civil engineering field, torsion and distortion effects are arousing more and more concerns of design engineers.Firstly, according to the membrane analogy theory by Prandtl, analyzed free torsion of multicell box girders. Calculation formulas for shear force flow and warping displacement function.Based on generalized Vlasov variational method, torsional warping displacement and stress of the multicell box girders are analyzed. According to the force method equation, the constraint torsion shear flow is calculated.Meanwhile the constraint torsion differectial equation is got by the common method,and then its parameter format is deduiced.Take the double box girders cross section as an example,the torsion center computational formula is got according to the reciprocal work theorem.Using the force and moment balance principle,the eccentric loading in any optional position can be divided into distoration load,bending load and toration load. From the analogy relationshipbetween box beam distortion differential equations and differential equations of elastic foundation beam deflection distortion differential equations,the variable cross-section box beam distortion analysis element stiffness matrix is deduced.At last, the Hanjiang Bridge is studied in this dissertation, and finite element program ANSYS is adopted to emulate the bridge model.After applied two distorsion loads on the model, the three directions’distortion displacement variation can be got,and the distortion effect of diaphragm numbers can be got from the comparasion of the model stress under the bending load and tortion load.Then the diaphragm thickness is changed,the distortion effect of diaphragm thickness is got from the observed change of the distoration displacement and stress.