高温作用后不等肢L形截面型钢混凝土柱偏心受压性能试验研究

Experimental investigation on eccentric compressive behavior of L-shaped SRC columns with unequal limbs after high temperature exposure

对8根不等肢L形截面型钢混凝土柱进行高温作用后的受力性能试验研究,1根未受火柱作为对比试件。柱配钢形式为桁架式配钢,试验中考虑加载角与加载偏心距的影响。通过试验,获得试件破坏形态以及承载力、截面平均应变分布、荷载-滑移曲线和截面变形特性。研究结果表明：柱肢内侧两面受火1 h的不等肢L形截面型钢混凝土柱仍然具有较高的竖向承载能力;空腹式配钢与合理的腹杆布置能够保证型钢与混凝土的协同工作,应变平截面假定仍然适用;不等肢L形截面型钢混凝土柱长肢方向的截面弯曲刚度较短肢的大,加载角0°时的刚度大于加载角45°时的刚度。

The mechanical properties of eight L-shaped steel-reinforced concrete （SRC） columns with unequal limbs after high temperature exposure were investigated. An unburnt column was tested for comparison. All steel skeletons in the columns were in the form of trusses. The effects of load eccentricities and loading angles were investigated. The failure form, bearing capacity, strain distribution over the cross-section, load-slip curves and cross section deformation characteristics of the specimens were obtained from the tests. The test results show that the bearing capacity of L- shaped SRC columns does not significantly decrease after being exposed to fire. The composite action between the steel and the concrete can be ensured by proper arrangement of the steel and web members so that the plain section assumption still applies. The lateral stiffness of the longer limb is greater than that of the shorter limb, while the stiffness of SRC columns loaded in the direction of 0° is greater than the corresponding ones loaded in the direction of 45°.