Fire Resistance Analysis And Resistant Design Of Long-span Suspendome Structure

The mechanical properties of steel such as elastic modulus and yield strength are significantly reduced under high temperatures of fire.In recent years,the human and economic losses caused by fire accidents in large-span space structures have been severe.The research on fire resistance of large-span space structures is of great significance.Based on the actual project of Tianjin University of Traditional Chinese Medicine Gymnasium,this paper studies and analyzes the fire resistance performance of continuous support and discontinuous support suspendome structures under high temperature of fire,and conducts performance-based fire resistant design on the roof structure of Tianjin University of Traditional Chinese Medicine Gymnasium.The contents and conclusions of research are as follows:(1)Introduced the basic principle of the fire resistance analysis method of large-span space structure,compared and analyzed the advantages and disadvantages of common methods of temperature field simulation under high temperature of fire,introduced the finite element analysis software ANSYS and fire dynamic simulation software Pyrosim,the process of fire resistance analysis and performance-based fire resistant design of large-span space structures is proposed.(2)The ANSYS software is used to analyze the fire resistance of structures under high temperature.The two parameters of the fire source location and the heat power of the fire source are changed to study the fire resistance of the structure with continuous and discontinuous support.The research shows that the maximum vertical positive displacement of the suspendome structure under high temperature of fire exceeds 3 times than under normal temperature,and attention should be paid to the "up arch" phenomenon of the upper reticulated shell;The average prestress loss of the first and second ring cable exceeds 75%,and attention should be paid to the fire protection of the first and second ring cable.Meanwhile,the suspendome structure with discontinuous support should be examined whether the compressive stress member at the local truss fails.(3)The Pyrosim software is used to accurately simulate the fire temperature field,which is compared with the fire air heating formula in a large space.The results show that the temperature distribution of the fire temperature field simulated by the former is more uniform,and the temperature gradient of the fire temperature field calculated by the latter is larger,and the temperature drops faster when away from the fire source.The data processing program has been compiled to enhance the interaction between Pyrosim and ANSYS.(4)Use the simulated temperature field to calculate the fire resistance of the suspendome structure,and recommend the fire resistance Design of the fire resistive coating which is in the area 1,3,5,7,17 of the structure of the gymnasium roof of Tianjin University of Traditional Chinese Medicine.In this method,the maximum vertical positive displacement of the structure when the fire is carried out to 1h is0.083 m,which is 40.71% less than that of the structure without fire protection measures,which is 70% in area less than the conventional method.