标准火灾作用后矩形钢管混凝土柱剩余承载力的研究

通过对6个矩形截面钢管混凝土柱按ISO-834标准升温曲线升温作用后的试验，研究火灾作用后矩形钢管混凝土柱的力学性能和剩余承载力。结果表明，在本次试验参数范围内，火灾后裸钢管混凝土柱的承载力损失严重。在确定了钢材和混凝土在高温作用后应力~应变关系模型的基础上，本文计算了火灾作用后矩形钢管混凝土压弯构件荷载~变形关系曲线，理论计算结果得到试验结果的验证。在分析了各参数，如火灾持续时间、构件截面含钢率、钢材种类、混凝土强度等级、荷载偏心率、构件长细比、截面高宽比和构件截面尺寸等影响的基础上，本文提出火灾作用后矩形钢管混凝土柱承载力实用计算方法。

RESIDUAL STRENGTH OF CONCRETE FILLED STEEL TUBULAR COLUMNS WITH RECTANGULAR SECTIONS AFTER EXPOSURE TO STANDARD FIRE

After exposure to the ISO-834 Standard fire, the behavior of six concrete-filled steel tubular columns with rectangular sections has been experimentally investigated and the results are presented in this paper. It is found, within the scope of the test, the strength loss of the specimen without protection is significant. A model is developed in this paper for concrete-filled steel tubular columns with rectangular sections after exposure to the ISO-834 standard fire. The predicted load versus mid-span deflection relationship for the composite columns is in good agreement with test results. Influences of the parameters, such as steel ratio, steel and concrete strength, load eccentricity, slenderness ratio, length-to-width ratio of the section and sectional dimensions on the strength loss ratio are analyzed. A simplified model is developed for calculating the member capacity of concrete-filled steel tubular columns with rectangular sections after exposure to the ISO-834 standard fire.