三种升温模式下钢构件火灾危险性分析

Fire Hazard Analysis of Steel Members in Three Heating Modes

为了研究变电站中可能出现的标准火灾、电力火灾和碳氢火灾三种火灾模式对无防火保护钢构件的影响,首先使用自制的耐火实验炉对三种火灾升温模式下不同厚度钢板达到临界温度的时间进行了实验分析;然后采用ABAQUS软件对实验结果进行了模拟复现,并对不同升温模式下钢构件达到临界温度的时间与钢构件荷载比的关系进行了数值模拟。结果表明:标准火灾升温模式下钢构件达到临界温度的时间为16~23 min,电力火灾、碳氢火灾升温模式下钢构件达到临界温度的时间为2~6 min,电力火灾和碳氢火灾升温模式下钢构件达到临界温度的时间相对标准火灾升温模式有急剧缩短,平均缩短幅度超60%,最大幅度达86.3%;数值模拟结果显示电力火灾、碳氢火灾升温模式下钢构件荷载比大于0.70时其达到临界温度的时间均低于6 min,钢结构稳定性失效的危险性较大,且钢构件的荷载比越大其到达临界温度的时间越短,两者之间具有较强的线性关系。该研究结果对多种火灾升温模式下钢构件的防火保护设计具有一定的参考价值。

To study the effects of three possible scenarios of standard fire,electric fire and hydrocarbon fire on steel members without fire protection in the substation,firstly,an experimental analysis was carried out on the changes of the time for different thicknesses of steel plates to reach the critical temperature under three fire heating modes by using a homemade fire-resistant experimental furnace.Then,the experimental results were reproduced by simulation using the ABAQUS software and numerical simulation was carried out on the relation between the time to reach the critical temperature and load ratio of the steel members under different heating modes.The relationship between the time to reach the critical temperature and the load ratio of steel members under different heating modes was simulated numerically.The results show that the time for steel members to reach the critical temperature value in the standard fire heating mode is 16-23 min,and the time for them to reach the critical temperature in the electric fire and hydrocarbon fire heating modes is 2-6 min,and the time for steel members to reach the critical temperature value in the electric fire and hydrocarbon fire heating modes reduced drastically relative to the standard fire heating mode,with an average reduction of more than 60%and a maximum reduction of 86.3%.The numerical simulation results show that the time for steel members to reach the critical temperature in the heating mode of electric and hydrocarbon fires is less than 6 min when the load ratio of steel members is greater than 0.70,and the danger of the stability failure of steel structure is great.The greater the load ratio of steel members,the shorter the time for them to reach the critical temperature,and both of them have a strong linear relationship.This study results have certain reference value for the design of fire protection under various fire heating modes.