Practical Analysis Of Reinforced Concrete Frame Structure Fire Response

Building fire is serious hazard to people's life and property safety. The researchers and the engineers have consistently focused their attention on the mechanical property at elevated temperature and fire safety design of the reinforced concrete structure, which is one of the most commonly used in construction. Based on the project imbrued especially by Hunan Province Construction office, the study of this paper includes four parts as follows:1. Two-dimensional temperature stiffness matrix is derived. Then, the software calculating the temperature of concrete members is complied by using Visual Basic 6.0. The fact that the calculation results coincide well with experimental results and ANSYS results shows that this software is reliable.2. After transferring the concrete members under fire to equivalent one at normal temperature based on the two step model, the formula was established to calculate the ultimate bearing capacity and deformation of concrete members Then, an example of calculating simply supported beam's deflection under fire is carried out. Comparing the calculating result and the experiment result, it is found that the result calculated by this method inosculates well with the one produced by experiments, which shows this method fits for engineering precision.3. Based on the existing researches of fire-resistance of steel frame structure and reinforced concrete frame structure, the formula was derived to calculate internal force and deformation of reinforced concrete frame under local fire. First, calculate the members' equivalent Section, then piled up the internal force and deformation produced by the loads and temperature; we can get the whole system to analyze the RC frame under local fire. At last, an example is taken and the results inosculates well with the one produced by finite element software-ANSYS.4. It carried out a practical method to decide fire-resistant limit of the whole structure based on plastic limit analysis. And the method of equivalent explosions fire time is presented. At last, an example is taken and the results inosculates well with the one produced by experiments; it also shows that the initial loads have great influence on fire-resistant limit of the whole structure.