内置钢管高强混凝土芯柱的十字形异形柱高温后轴压性能试验研究

Experimental research on after-fire axial compression performance of cross-shaped composite column with high strength concrete-filled steel tubular core column

为提高钢筋混凝土异形柱的受力性能,在钢筋混凝土异形柱中设置钢管高强混凝土芯柱,形成内置钢管高强混凝土芯柱的组合异形柱。为研究该类型组合异形柱在历经高温后的受压性能,开展了3个足尺十字形组合异形柱试件在历经ISO 834标准明火试验后的轴压试验和1个未受火组合异形柱试件的轴压试验,分析了不同受火时间对内置钢管高强混凝土芯柱的组合异形柱的破坏形态、轴向变形和轴向承载能力的影响。结果表明:处于试件内部的芯柱承载力高且升温较慢,由芯柱所提供的轴向承载能力和竖向刚度受高温影响较小,受火时间为90 min和120 min异形柱试件的剩余承载力系数分别为0.839和0.761,具有较高的剩余轴压承载力。

To improve the mechanical performance of the reinforced concrete special shape column,a high strength concrete filled steel tubular（ CFST） core column was utilized. In order to investigate the after-fire performance of this kind of composite special shape column,tests of four full-scale composite cross shape column specimens were conducted. Three of these specimens were firstly burned under ISO 834 standard fire and then axially compressed to failure,while the fourth composite column specimen was only axially compressed to failure. The effects of the firing time on the after-fire failure patterns,axial force capacity,axial deformation of the CFST core column was analyzed.The test results indicate that the CFST core column is very beneficial to improve and sustain the after-fire capacity and rigidity of the special shape column,because the core column in the center of the column is difficult to heat up. The effect caused by fire on axial compression capacity and axial rigidity of the core column is slight. The CFST core column can sustain high axial capacity, the residual axial compression capacity ratio is 0. 839 and 0. 761,respectively,corresponding to the time of 90 min and 120 min,respectively.