大空间单跨门式刚架结构抗火性能影响因素的客观权重研究

火灾时的大空间单跨门式刚架结构抗火性能,受钢构件温升和结构整体抗火临界温度的影响。本文通过对无保护大空间建筑钢构件温升数据的统计分析,获得包含火源功率、建筑体积、钢构件截面形状系数的钢构件温升拟合公式;结合单跨门式刚架结构整体抗火临界温度数据的统计分析,获得包含荷载比、柱高和系数K的结构整体抗火临界温度拟合公式;通过分析上述因素对钢构件温度变化率及抗火临界温度变化率的影响,获得各个因素的客观权重值,并应用于具体案例的结构安全分析。结果表明,在本文的研究条件下,荷载比权重值最大,约为0.4;火源功率是仅次于荷载比的一个重要因素;建筑体积、截面形状系数和系数K三者都在其自身值较小时,权重值较大,且都随着其自身值的增加,权重值降低。本研究可供无保护门式刚架结构建筑的抗火设计、火灾风险评估和消防管理作参考。

Study on Objective Weight of Fire Resistance Factors of Large-Space Single-Span Steel Portal Frame Structures

Fire resistance behavior of large-space single-span portal frame structures is influenced by steel components temperature rise and fire-resistance critical temperature of whole structure.Based on statistic analysis of temperature rise data of non-protected large-space structure steel components,we got a temperature rise fitting formula of steel component considering fire source power,building volume,cross-section shape coefficient of steel component.Combining with the statistic analysis of the whole structural fire-resistant critical temperatures data of single span steel portal frames,we got an another whole structural fire-resistance critical temperature fitting formula considering loading rate,column high and coefficient K.Through the analysis of influence of above factors on the temperature gradient of steel components and fire-resistant critical temperature change rate,we obtained objective weights of different factors,and used them for some specific cases.Results show that loading rate is the most important factor with a maximum weight about 0.4.Fire source power is the second important factor.When the building volume,cross-section shape coefficient and coefficient K are small,their weight values are great,their weight values decrease with increases of themselves.This study offers a support to fire risk assessment of non-protected portal frame structural buildings and give a reference to fire-resistance design and fire control management.