常温及火灾后异形钢管混凝土短柱轴压力学性能试验研究

Experimental Study on the Axial Compression Behavior of Special Shaped Steel Tubular Short Columns at Room Temperature and After Fire

通过对8根试件中6根受火后的T形钢管混凝土短柱轴及2根未受火T形钢管混凝土短柱轴受力性能的对比试验,分析了混凝土短柱轴火灾后轴压力学性能。试验结果表明,混凝土短柱轴无论受火温度为多少,其荷载随着位移的增加而增加,在增加到一定程度后趋于稳定。随着混凝土应变的增大,尽管受火温度不同,但混凝土短柱的应力均随着应变的增大呈现先增大后减少的趋势。随着火温持续时间的延长,T形钢管混凝土短柱的剪力滞比基本呈上升趋势,当火温持续120 min时,剪力滞比最大值接近7.0。随着挠度的升高,温度随挠度升高而呈非线性增加,在挠度达500 nm后,温度增长速度变快。未受火灾的T形钢管混凝土在混凝土变形ε/με为2 000时,荷载出现最大值;而火灾作用后,在ε/με为6 000时,荷载出现最大值。

In this paper, based on 8 specimens of 6 under fire after the T-shaped steel pipe concrete short columns and 2 without fire T-shaped concrete-filled steel tubular short column by the contrast test of mechanical properties, analysis the concrete short columns in fire rear axle pressure performance. The results show that the load of concrete short column increases with the increase of the displacement, and it tends to be stable after increasing to a certain degree. With the increase of concrete strain, the stress of concrete short columns increases first and then decreases with the increase of the strain, even though＇the temperature of the fire is different. With the extension of the duration of fire temperature, the shear lag ratio of T shaped steel tube concrete short columns is increasing, and the maximum value of the shear lag ratio is close to 7 when the fire temperature is 120 min. With the increase of deflection, the temperature increases with the increase of the deflection, and the temperature increases quickly after the deflection reaches 500 nm. Without fire of T-shaped concrete-filled steel tube in concrete deformation ε/με is 2 000, load up to a maximum value; and after fire, at ε/με 6 000, the load appears maximum.