耐火钢圆钢管混凝土柱耐火极限和承载力

摘要

为了得到耐火钢圆钢管混凝土柱的防火性能，利用ANYSY有限元软件对火灾升温曲线下钢管混凝土柱进行温度场模拟，变化钢管直径、长细比、含钢率、钢材强度、混凝土强度、受火时间、荷载偏心率、荷载比等参数，采用数值计算方法求解耐火钢圆钢管混凝土柱耐火极限和承载力。提出耐火极限和承载力的实用计算公式，公式与数值计算结果吻合度高，可为有关工程的抗火设计提供参考。研究结果表明，与普通柱相比，在一定时间内耐火钢圆钢管混凝土柱耐火极限和承载力提高显著，因此可减薄甚至取消防火涂层。%To know about fireproof performances of concrete filled tubes(CFT) of fire‐resistant(FR) steel with circular cross‐section ,the temperature field of CFT of ordinary steel under the fire heating curves was simulated using ANSYS .The fire resistance and load‐bearing capacity of CFT of FR steel were solved with numerical technique under different diameters , slenderness ratio , steel ratio , steel strength , concrete strength ,exposure time ,load eccentricity ratio and load ratio . The simplified calculation formula for predicting the fire resistance time and bearing capacity was deduced , which is found to be in good agreement with numerical results .The calculation formula may be referenced for the fire protection design of practical engineering .Parametric analyses show that the fire resistance time and bearing capacity of CFT of FR steel increase significantly in a certain period of exposure time compared with CFT of ordinary steel . Therefore ,the thickness of fire‐proof coating can be decreased or abolished .