Theoretical Analysis On The Fire Performance Of Steelconcrete Composite Beam Protected By Refractory Fibers

Steel-concrete composite beam structure has outstanding seismic performance and economic benefit, because it can give full play to material property of steel and concrete. It is one of the most important development direction of high-rise buildings. If fire accident occurs, the temperature will rise quickly, strength and stiffness of the steel beam will decrease rapidly, the failure of composite beam may occur in a very short time, due to the exposure of the steel beam. As the third generation of refractories, Due to the small coefficient, good resistance to spalling and other series of advantages, refractory fiber is a new direction for the development of fire protection materials. Research work on the fire performance of steel-concrete composite beam with refractory fibers is almost in a blank at home and abroad, therefore studying on this area is of great theoretical significance and practical value. The primarily contents of this paper are as following:Based on analysis and research of current achievements on thermal and mechanical properties of refractory fiber,concrete and steel under high temperature, thermal parameters and constitutive relationship for refractory fiber, concrete and steel are determined.A general finite element analyzing software(ABAQUS) is utilized to establish the 3D model for the fire performance of steel-concrete composite beam with refractory fibers simply supported at both ends, which was verified by experimental data.The verified model was used to analyze the influence of refractory fiber on the steel concrete composite, and compared the differences between crefractory fibers and fireretardant coating. Influences to fire-resistant performance of composite beam including of thickness of concrete slab, steel sections height, steel flange width, thickness of refractory fibre, load ratio.To study the fire resistance of the fire performance of steel-concrete composite beam with refractory fibers. A series of influence parameters were analyzed. Based on the parametric analysis results of plenty of parameter analysis, simplified calculation formula is put forward for fire-resistant design of composite beam with refractory fibers, which can provide reference for the fire-resistant design of concrete composite beam with refractory fibers simply supported at both ends.