Analysis Of Mechanics Characteristics Of Steel Truss And Prestressed Steel Truss In High Temperature (Fire) Condition

Steel truss which serves as an important component of steel structure has been widely used in various construction and infrastructure. Compared with other forms of structures, st eel structure has the advantages of high strength, light weight, simple operation, short-time lap and valuable recycling. However, compared with other structures again, the poor firere-sistance property of the steel structure is fatal. Especially the large amplitude attenuation of mechanical property under the high temperature causes great negative impacts on the nor-mal use of the steel structure building. Therefore, it is meaningful to research on the steel structure and the fire resistance property of prestressed steel structure.This essay mainly talks about steel truss and prestressed steel truss. It carries on the theoretical analysis at first. Then, steel truss and prestressed steel truss under different cir-cumstances were analyzed in the state of normal temperature and high temperature. Finally, analyzing the coupled thermo mechanical of the steel truss model by using the finite elem-ent software ANSYS.The research shows as follows:First, through the theoretical analysis on the steel truss, the changes which caused by internal force and bearing capacity of the steel truss and prestressed steel truss in the state of the normal temperature and high temperature can be analyzed. That is to say, with the increase of temperature, the internal force and displacement of steel truss and prestressed dragline are increasing nonlinearly while the bearing capacity is decreasing.Second, by comparing the controlled variable of the steel truss and prestressed steel truss under the different circumstances, we can analyze the influence on internal force, dis-placement and bearing capacity which is affected by different temperature and rate of tem-perature rise. It also needs analyzing the changes in the relationship between the loss of pr-estress and temperature rise in the prestressed steel truss. In other words, the rate of tempe-rature rise would affect the structure and the bearing capacity of prestressed dragline direc-tly. With the increase of temperature, the loss of the prestress will also increase.Third, analysis of coupled thermo mechanical to the steel truss by using the finite ele-ment software turns out relationships between the temperature and mechanical property. These studies will provide reference for the research on the fire resistance of prestressed steel structure. Hoping that it would also provide reference for engineering applications in the future.