矩形截面钢管混凝土巨柱抗火性能分析

Analysis of fire resistance performance of mega concrete-filled steel tube columns with rectangular section

超高层建筑的防火设计提高了主要结构构件的耐火极限要求,由于超高层建筑中矩形截面钢管混凝土巨柱的尺寸较大,通过试验研究其抗火性能不太现实,本研究通过有限元软件采用顺序热力耦合的分析方法,得到了不同设计条件下矩形钢管混凝土巨柱截面的温度场分布以及巨柱轴向变形随受火时间的变化。分析结果表明:轴压比对矩形钢管混凝土巨柱抗火性能的影响较大,对承受较大轴压比的巨柱需要特别注意其防火保护;通过增加内置钢隔板、增加截面尺寸和喷涂防火涂料均能在一定程度上提高巨柱的耐火极限,分析结果可为超高层建筑的防火设计提供一定参考。

The fire protection design of super tall buildings increases the fire resistance limit requirements of the main structural components of the buildings.Due to the huge size of the rectangular concrete-filled steel tube columns in super tall buildings,the thermal and mechanical sequential coupling analysis instead of fire resistance test is adopted to obtain the temperature field distribution of the section and the axial deformation of the mega column change with the fire time under different design conditions.Study results have shown that:the axial compression ratio has a great impact on the fire resistance of structural components,and special attention should be paid to the fire protection of huge columns which bear large axial compression loads.Adding built-in steel partitions,increasing cross-sectional dimensions or spraying fire-resistant coatings can be used to increase the fire resistance limit of huge columns.The analysis data can provide a reference for the fire protection design of super tall buildings.