Model Test Study And Analysis On Torsion Effect And Distortion Effect Of Box-girder With Corrugated Steel Webs

The composite box girder with corrugated steel webs is a new type steel-concrete composite structure. It has gained wide application in Japan and France. Compared with traditional concrete box girder, this structure holds specific mechanical behavior, lightens self-weight, enhances loading efficiency of external prestress, completely avoids the generation of skew cracks, so it will obtain extensive use in the future. The dissertation makes systematical research on torsion and distortion of box girder with corrugated steel webs.(1)On the basis of design theory for box girder, and combined with its structural property, the Second Theory of A.A.Umanskii is adopted for analyzing its torsion and calculation methods under an eccentric load.(2)The distortion differential equation of box girder with corrugated steel webs is similar to the distortion differential equation of spring foundation beam, so equation of box girder can be solved by the method of B.E.F analogy combined with finite element method when distortion effect is considered.(3)Through the load model test at the elastic stage, it proves that the warping stress and the torsion shearing strength, attained by the Second Theory of A.A.Umanskii and the method of B.E.F analogy combined with finite element method, is well approximately. Result from the finite element program Ansys also agree with measured warping stress and measured torsion shearing strength. It shows that the calculational method is proved to be valid, and the result is inclined to be conservative.(4)The geometry parameters are carried out to analyse the influence mechanical performances of box girder under eccentric loads. Compared with the result from the box girder which is not set up the certain diaphragm, we know the diaphragm can reduce the distortion effect. Efficient engineering measurement is setting up diaphragms to reduce warping stress.Finally, according to the result from the analysis of geometry parameters, some advice can be used for the preliminary design of composite box girder with corrugated steel webs.