Research On Calculating Theory Of Prestressed Concrete Filled Steel Tubular Structures

The concept of the prestressed concrete filled steel tubular (CFST) structure is introduced in this paper,which is to set prestressing force in CFST members and to enhance the bearing capacity of the structures. By studying its calculation theory,it is pointed out that the prestressed CFST structure not only enhance the application scope of CFST effectively,improves its quality,but also gives full advantages of the composited structures.The following works have been done in this paper:1. On the basis of establishing the model of the axial tensile members of the prestressed concrete filled steel tubular,two-step design method is used to explain the principle of work and the stability bearing capacity of the structure at the stage prestressing is analyzed;2. According to the characteristic of the unbonded prestressed concrete filled steel tubular,the factors affecting the prestress losses are analyzed and the basic method of calculating the prestress losses is induced;3. By satisfying the equilibrium of inter-force and coordination of deformation,the stress and the loading capacity of the prestressed concrete filled steel tubular structure are analyzed and calculated;4. By calculating an engineering example,the calculation theory of the prestressed concrete filled steel tubular is verified.