四面受火胶合木柱耐火极限试验研究

Experimental study on fire endurance of glulam columns exposed to four-side fire

通过4根胶合木柱耐火极限试验,对四面受火胶合木柱的升温规律和耐火极限等进行了详细研究,主要考虑了截面尺寸对其耐火极限的影响。研究结果表明:两个未受火对比试件均在柱中附近折断;测点离木截面表面距离越近,温度越高;且不同试件距边缘相同距离测点温度随时间的变化规律接近;荷载比为0.2的200mm×200mm截面胶合木柱耐火极限为47min,而荷载比为0.2的150mm×150mm截面胶合木柱耐火极限为35min,可见相同荷载比的胶合木柱,截面较小的木柱耐火极限较低。

The temperature development law and fire endurance of glulam columns exposed to four-side fire were carefully studied through fire endurance tests on 4 glulam columns. The effect of cross-section geometry on their fire endurance was considered. Results show that both un-exposed control specimens are snapped close to the mid-span of columns. The closer the thermocouples to the surface of glulam column are,the higher their temperature is. Also,for the thermocouples at different specimens with the same distance to the surface of glulam column,temperature varies similarly with the fire exposure time. The fire endurance of glulam column with the cross-section size of 200 mm × 200 mm under the load ratio of0. 2 is 47 min,while the fire endurance of glulam column with the cross-section size of 150 mm × 150 mm under the load ratio of 0. 2 is 35 min. It shows that for the glulam columns with same load ratio,the column with smaller cross-section size has shorter fire endurance time.