The Theoretical Analysis On The Bending Resistance Capacity Of Prestressed SRC Simple Supported Beams Under Fire And Load

Compare to the prestessed reinforced concrete beam, the prestressed steel reinforced concrete beam have greater stiffness, lighter weight, more applicability of resisting crack and earthquake effects. And these have broad application prospects in the transfer structures of the high-rise building, large span, heavy-load industrial structure, bridge and underground building. Building fire is serious hazard to people's life and property safety. So the research of fire resistance of prestressed concrete structures is very important. At present,the research of composite structure of prestressed profiled iron and concrete at home and abroad have not been perfected. In this paper,flexural performance under fire and behaviors after fire of prestressed steel reinforced concrete simple beams have been studied in the tests,and its fire resistance behaviors are analyzed with the method of theoretical analysis and numerical calculation together.The main contents of the results of research are as following:(1)Through fire flexural performance test research of prestressed steel reinforced concrete simple beams, the investigate temperature distribution, reveals the deformation law and the degradation of the beam's mechanical performance under coupling action of the load and fire are discussed.(2)Through the loading experiments of the prestressed SRC simple beam after fire, the bending resistance capacity of elements after fire is studied and analyzed.(3)Based on the result of the experimental study, the bending resistance nonlinear finite element analysis of the prestressed SRC simple beam under coupling action of the load and fire is carried out, which is compared with the real measure result.(4) Based on the effective section method, the paper deduces practical formulas method for calculating stiffness of the prestressed SRC simple beam after fire,which the results agree well with the tested ones.