Study On Fire Resistance Design Of Steel Structures

The steel structures are widely used in modem building structures due to its superior properties such as high strength, light weight, good ductility, rapid construction and so on. However, the poor fire-resistant ability is the fatal weakness of the steel structures. Its yield strength would decrease to half of the yield strength under room temperature when the temperature is up to 400℃, and the strength and rigidity will almost totally lost when the temperature is up to 600℃. Therefore, the study on the fire resistance and fire-resisting design of the steel structures has great meaning.In the paper, the development and the existing problems in fire design and fire protection methods of steel structures is reviewed. The norms required fire resistance level of different structures is represented. The duration of fire resistance defining method and the main influencing factor for fire-resistant ability of steel structures are discussed. The test-based and calculation-based fire resistance design methods of the steel structural elements are stated. The mechanical property and the ductility of constructional steel under high temperature are introduced. Also, the passive fire protection method and the active fire protection method of steel structures are expounded. The constitution and the thickness of the anti-fire protection cover are discussed. Finally, the real application of fire protection method to the steel structures in one passenger station waiting hall and one joint ship manufacturing plant is formulated.After comparing the different methods for fire-resisting design under standard fire hazard conditions and practical fire hazard conditions, the irrationality of the fire-resisting design method established in national building fire-resisting design codes which is based on the fire-resistant ability of elements is proposed. In addition, the performance-based study of fire-resisting design is presented.