Nonlinear Finite Element Analysis Of Steel Frame Column In Fire

The poor fire-resistance ability is the main weakness of steel structure in that its mechanical property such as strength and elastic modulus decrease severely in high temperature. When fire occurs, severe damage or global collapse will happen to the steel structure. In china, test-based fire resistance design method is the prevailing fire resistance design method for steel structures. However, using the test-based fire resistance design method, it is hard to simulate the magnitude and distribution of loads and the end restriction conditions of the specimens in the structure. The ultimate fire resistance of the steel structure and the fire protection measures can be determined through calculation-based fire resistance design method. Therefore, a thorough study of the calculation-based fire resistance design method has great theoretical significance and practical value.In this paper, based on the problems on the fire safety design of steel structures, the following researches have been accomplished. Considering the effects of static load and thermal stresses, the buckling analysis of steel I-section is applied. Considering the effects of stress redistribution, the stress of steel frame column in fire is studied. By building entitative model, the local buckling of steel I-section column is studied. We have build different slender ratio column and find the slender ratio will influence the form of local bulking. We have built steel frame damnified by earthquake and have studied how much the different damnification reduce the fire resistance of the column by the finite element method.