Experimental Study On Ultimate Capacity Of Composite Continuous Girders With Corrugated Steel Webs

The composite box girder with corrugated steel webs is a new structure applying external prestressing technique to bridge construction. Compared with normal concrete box girder bridges, in addition to completely avoid the web cracking, this structure has many other advantages, such as force definite, lighter weight, beautiful appearance, and convenient for construction. It is expected that this structure will be strongly promoted and widely used for engineering practice. However, because of lacking theoretical and experimental research, there is no specific standard to guide practice. Therefore, based on previous studies of continuous beams with corrugated steel webs, some studies were carried out in this thesis to develop more understanding of its structure performance. Thus, the main contents are as follows.The two-span continuous box girder with corrugated steel webs was designed and produced. In order to study the structure in the elastic stage of the various mechanical properties, this test beam is researched in the deformation behavior experiment after prestressed and the cracking behavior experiment of the section of maximum positive moment and negative moment. The results show that the box girder with corrugated steel webs has a feature of stressing definitely.According to the classical principle of virtual work, deflection formulas of composite continuous beam are obtained, which can be used for elastic analysis and plastic analysis. Furthermore, at the elastic stage, relationship between the bending deformation and shear deformation of test model under the inter-concentrated load was showed.On the basis of experimental study on ultimate capacity of the composite continuous beams, the thesis got deformation and stress of structure in the non-elastic, Verified the girder Steel-Concrete surface connection reliability. Also, the characteristics of box girder with corrugated steel webs were presented, moment modulation theories about continuous beam with steel webs or concrete webs were summarized. With the structural design theory, the ultimate bearing capacity of the composite continuous beams was received.Accounting for the existing research data, selecting the right material constitutive model, the thesis took cross section N-M-Φrelationship into consideration, and then a nonlinear finite element program for linkage structure was designed. The results were in good agreement to the experiment. Finally, by the section of plastic indexφu-φy, the influence of the prestressing force level on the section plastic was presented.