Performance-based Analysis For Fire Response Of Steel Tube Truss Structure

The analysis of fire-response of steel tube truss structure is quite important part in the study of fire-resistance of large space steel structure because the obvious advantages in the structure form and economic benefit.Taking the Taiyuan International Exhibition Center as an engineering background,the fire-response of steel tube truss structure is studied.The main contents are as follows:Using steady state and transient test methods,the mechanical properties of Q345 steel tube are studied.The difference of the mechanical properties caused by the test method is very obvious.Therefore,the models at high temperatures are presented based on the transient test,the correctness and feasibility of which is verified comparing with some classic models.The fire safety goal is taking based on the design method of performance-based fire-resistance,and four kinds of the most dangerous fire scene are determined analyzingthe risk of fire,fire load,fire location and fire protection system.Unappropriation of traditional ISO standard heating curve and large space fire air heating utility curve in simulating the temperature of large space building is verfied.The temperature distribution in large spacebuilding is analyzed by using FDS software.The results show that,the temperature is obvious uneven distributed,and fire location and fire area are both effect on the temperature disturbution.The heating curves of each member of different fire scenes are calculated with MATALAB software according the practic elevation of fire temperature of steel members,the temperature of which can be reach 334.41℃,292.60℃,240.24℃ and 211.26℃.The fire-response and the change of mechanical properties aftering local cooling of the steel tube truss structure in different fire scenes are simulated by ANSYS software.The results show that the section area of the chords near the ends should be increased appropriatly,and the size of cantilevered part should be decreased.In the process of using and maintenance,the combustible matter should be far away from the ends of roof,at the same time the area of combustible matter should be small as far as possible,and the higher booth should be arranged at the areas of higher clearance.The water cooling to the high temperature members of steel structures should be avoided.The research results can provide references for the fire-resistance design and safety assessment of steel tube truss structure.