Research On Fire Evacuation Of Steel Structures Based On Fire Simulation And Personnel Evacuation Simulation

Large-space steel structure is mostly used for multi-purpose stadiums,convention&exhibition centers,museums,airports,parking lots,large shopping malls and other buildings,and is today’s one of the most important structural forms for large public buildings.For example,China’s 2008 Beijing Olympic venues of Bird’s Nest and Water Cube and the 2010 Shanghai World Expo venues have all promoted the development of steel structure building.While steel is of poor fire resistance,since its mechanical properties such as yield strength and elastic modulus will be significantly reducedwhen under high temperature,in the case of fire,its structure is prone to damage.Therefore,it is particularly important to figure out the fire-protection design and reasonable evacuation measures for steel structure buildings.Based on three kinds of different steel structure buildings,this paper conducts fire smoke simulation and personnel evacuation simulation on the atrium-type comprehensive steel structure buildings,arc-shaped roof steel structure buildings and steel structure buildings with a high concentration of people,and has concluded the following data:(1)Taking a comprehensive steel structure building as an example,using FDS software simulation and empirical formula calculation method to respectively determine the temperature of two specific elevation parts near the steel structure under three fire scenes.The results show that when the elevation is 58.6m,the highest temperature is 120 ℃ in the fire scene 3 and when the elevation is 61.1m,the highest temperature is 125 ℃ in the fire scene 1.(2)Taking a bicycle hall,an arc-shaped roof steel structure building as an example,using FDS software simulation and empirical formula to calculate,to respectively determine the temperature of the steel structure under the same scene;using standard method to calculate the yield strength of the steel structure and to analyze its relations with the maximum stress of the steel structure.The results show that when the steel structure is in fire.300 ℃ is the critical temperature at which the maximum stress and its yield strength will change.When the temperature is higher than 300 ℃,the structure above the fire source will deform and cease to be in effect.(3)Taking a shopping mall as an example,by combining Revit software and Pathfinder software,this paper draws the BIM model of buildings,stimulates the people evacuation process,analyzes and discusses the results of evacuation.The simulation results show that the whole evacuation process embodies the phenomenon of fast is slow;stratified evacuation explains the influence of stair well and stair turning place(where personnel congestion and stagnation are easy to see)to the evacuation time.By reasonably opening and closing different stair wells,the evacuation efficiency can be enhanced.If the monitoring system can cover the staircase,when in an accident,by opening the stair wells,which have completed or is going tocomplete the evacuation,to other floors,the evacuation efficiencycan be increased to a higher extent.