Study On Calculating The Internal Force And Analysis For The Limit Under Fire Of RC Frame Structure Subjected High Temperature Of Fire

Building fire is one of the most serious disasters damaging the wealth and intimidating the safety of people. It leads to loss of the wealth and lives shocking by sight. Based on the project imbrued especially by Hunan Province Construction office, the study of this paper includes four parts as follows:The first part does some simplify on the characters of the RC material under high temperature. After transferring the RC section under fire to equivalent one at normal temperature based on the stiffness and intensity equivalent, the RC members under fire can be calculated as ones at normal temperature. Comparing the calculating result and the data from experiment, it is found that the result calculated by the simple method inosculates well with the one produced by experiments.In the second part, considering the depress of the stiffness of concrete caused by its transient thermal strain under fire, the current formulas can be conducted, and then the formulas to calculate the internal force and deformation of RC frame under fire can be conducted by structure mechanics.In the third part, to get the internal force and deformation produced by the loads, the frame can be analyzed as ones under normal temperature after making equivalent. Piled up the internal force and deformation, then, we can get the whole system to analyze the RC frame under fire. In this part the use of Ansys is also be introduced. As an example, it has been used to analyze a RC frame under fire.In the last part, the advice thinks it is more reasonable to use integer method to decide the limit time enduring fire. And it also carries out a simple calculation method to it. It is found that the result calculated by the simple method inosculates well with the one produced by experiments.