Experimental Study And Theoretical Analysis On Fire-Resistant Property Of Prestressed SRC Beam

The Prestressed steel reinforced concrete composite member is a new structure member which is based on the advantage of Prestressed reinforced concrete and steel reinforced concrete, it has high bearing capacity, greater stiffness, and good aseismatic performance. And it can be used in some critical structures, such as large span structure, heavy-load structure and the transfer structure of the high-rise buiding. So the safety of these members is very important to the reliability of the hole buiding. Fire has great influence to the prestressed SRC composite structure, and the effect of the component section temperature gradient might cause great temperature stress and deformation. The elastic modulus of the material decreases under fire and changes the failure mode, leading the bearing capacity to greatly reduce. So it is very important to research the fire resistance of prestressed SRC composite structure.The research object is prestressed SRC composite structure in this article. We test the fire resistance behavior of the structure under high temperature and load. And comparing the theoretical analysis and experiment, the fire resistance behavior of the prestressed SRC has been analysised and discussed. The main contents are as following:(1) By testing the fire resistance behavior of the structure under high temperature and load, the section temperature field distribution and the changing law of prestress on the end of the component and the deformation of the member are studied. The test reveals the deterioration mechanism of the mechanical properties.(2) Using the finite element method, we establish the formula of the bending ultimate strength of the prestressed SRC Simply Supported beams in high temperature. Compared with the result of equivalent section method, there are little difference. Using the equivalent section method, we establish the formula of bearing capacity of shear load within the inclined section, and the simplified formula of the stiffness in high temperature. The deformation of the calculated value is similitude with the measured value.