中空夹层钢管混凝土轴压短柱火灾后剩余承载力的试验研究

RESIDUAL STRENGTH OF CONCRETE-FILLED DOUBLE-SKIN STEEL TUBULAR STUB COLUMNS AFTER EXPOSURE TO FIRE

对6个中空夹层钢管混凝土轴压短柱开展试验研究,试验的主要参数是截面形式(圆套圆、方套方和方套圆)以及受火与否。试验结果表明,受火后中空夹层钢管混凝土轴压短柱的承载力下降显著。在空心率相同的情况下,方套圆截面形式的试件其剩余承载力最高,而圆套圆截面形式的试件其延性最好。同时还可以发现,火灾后中空夹层钢管混凝土的轴压承载力下降幅度与传统的实心钢管混凝土接近。

Test results of six concrete-filled double-skin steel tubular （CFDST） stub columns are presented. Circular hollow sections （CHS） and square hollow sections （SHS） were used to fabricate the inner and outer skins of the composite columns. The main parameters explored in this test programme were the section type （CHS inner and CHS outer,SHS inner and SHS outer,and CHS inner and SHS outer） and whether or not exposure to fire. It was found that the strength of the CFDST columns decreased significantly after exposure to fire. However, the residual strength of these innovative CFDST columns was still comparable to that of conventional concrete-idled steel tubular columns. Of all the three types of sections with a same hollow section ratio,the one with CHS inner and SHS outer shown the highest residual strength,whilst that with CHS inner and CHS outer shown the best ductility behaviour.