The Reliability Research Of Concrete Structure In Fire

Along with the accelerated process of urbanization, the personal and property losses caused by fire increased year by year, which draw more attention than ever. The buildings are the main sites of human activities, so the building security in the fire relates directly to the degree of loss. The building should have a certain degree of reliability in the fire, which has great importance to Personnel evacuation and fire-fighting. This is a question should be consider in architectural design.High temperature made the property of building material significantly attenuated, on the other hand, high temperature made the internal forces redistribution of structure, so the reliability of structure is greatly reduced. Existing safety study of building fire is mainly based on the ISO834temperature-time curve, which is a theoretical curve and not fully reflect the influencing factors of fire such as the distribution of fuel and ventilation of the building, also assume the whole room at the same temperature, so the result based on the ISO834temperature-time curve is very different with the actual scene. On the other hand, the reliability analysis of building fire lacks explicit limit state function, especially when the reliability calculation considers the internal force redistribution of the structure. Direct Monte Carlo simulation has no requirement of explicit limit state function, but it needs huge calculation efforts.To solve these problems, the Monte Carlo Method based on response surface is proposed from the view point of numerical simulation and experiment design. First the experimental is designed using uniform experimental method, then using the fire modeling software FDS the actual result of temperature can be obtained. On this basis, the force of structure and the bearing capacity of structure can be calculated using ANSYS and numerical analysis method. The reliability index can be calculated with the Monte Carlo Method based on response surface. Uniform design method can allocate more parameters without greatly increasing the calculation efforts.Using a case the calculation process is explained with. The results show that this method can quickly obtain the reliability index in the premise of less calculation.