Response Analysis Of The Plane Steel Frame Under Fire And Research On The Fire Protection

From the earliest clay structure building to wooden structure building, bamboo structure building, brick structure building and then to modern reinforced concrete structure building as well as the more and more popular steel structure building, the upgrading of building materials is becoming more and more quickly, as the rapid progress in the development of science and technology.As building materials, steel has lots of convenience and advantages, such as steel member’s industrial production, which accelerates the construction speed greatly. Compared to traditional building materials and other building materials, steel also has very obvious advantages such as the high strength, more light, good ductility and excellent seismic performance. But the shortcoming of steel is very deadly at the same time. Its refractory performance is very poor, although the steel is a kind of flame retardant materials. When subjected to fire disaster, the strength of the steel, the yield point, and other mechanical parameters will reduce rapidly as the increasing temperature, which becomes steel structure’s short board and limitations. In order to better use of the steel, we must pay more attention about its fire protection.In this thesis, by using the finite element software ANSYS, response simulation of the plane steel frame in fire condition have been made, including single span frame with fire inside, three layers and three spans steel frame which subjected to fire in the edge span or in edge and middle span at the same time respectively, and their fire proof limits and limit temperatures have been calculated. According to the simulation results, the contrast of temperature in the side column’s flange and temperature vs. mid-span displacement curve of the beam between the last two different conditions above-mentioned has been made.Besides, the destruction of the fire room is caused by the large deflection of the beam which exceeds the limit has been found out. Therefore I add ideal fire protection to the maximum temperature change part of the frame, as well as find out its finite element simulation. By comparison of beam heating speed and the extreme temperature to the one without ideal fire protection, I find out that fire protection can reduce the heating rate of the steel structure components greatly and make the highest temperature acceptable. I also calculate the ideal thickness of fire protection layer in the weak part of the steel frame. At last, in order to provide some useful information for further fire protection research, domestic and foreign latest fire protection technology and fire protection materials are summarized.