表面设置防火涂料高强混凝土柱的耐火极限

Fire Resistance Rating of High Strength Concrete Columns with Fire Insulation

前期试验表明,表面设置厚度20 mm的某非膨胀型防火涂料可较好地抑制高强混凝土的高温爆裂。本文通过试验反算给出了该涂料对应不同温度区间的平均导温系数;随后,利用结构抗火分析软件SAFIR对表面设置该涂料的高强混凝土柱的耐火极限进行了计算分析,考察了截面尺寸、轴压比、荷栽偏心率及配筋率等因素的影响,在此基础上提出了相应的高强混凝土柱耐火极限实用计算公式。研究结果表明:①该涂料的平均导温系数随温度升高有所降低;②表面设置厚度20 mm的该涂料可明显提高高强混凝土柱的耐火极限,提高幅度达40%～350%。

It is shown that a special fire insulation with a thickness of 20 mm is effective against explosive spalling of high strength concrete（HSC） at high temperature.Based on test results,mean thermal conductivity coefficients of the fire insulation are determined in different thermal ranges.Then,fire resistance performance of HSC columns with the fire insulation is analyzed by using the computer program SAFIR, and the influences of axial load ratio,cross - sectional dimensions,load eccentricity ratio and reinforcement ratio are discussed.Finally,a regressive formula is proposed for calculation of fire resistance rating of HSC columns with the fire insulation.Simulation results show that：（a） the thermal conductivity coefficient of the fire insulation decreases slightly with increase of temperature;and（b） the fire resistance of HSC columns with 20 mm thick fire insulation can be 40%～350%larger than those without the fire insulation.