防火涂料局部破损后约束钢柱的临界温度

为了研究防火涂料局部破损后钢柱的抗火性能，根据分段平衡微分方程，分别推导了两端铰支和固支的钢柱局部防火涂料破损后高温下的挠曲线方程，采用边缘屈服准则得出了局部防火涂料破损后轴向约束钢柱临界温度的计算方法。用有限元对高温下的挠度和轴向位移进行了验证，结果吻合较好。通过算例计算了两端铰支轴向约束刚度内力随温度的变化关系，并计算了临界温度。研究结果表明：轴向约束增加高温下钢柱的内力，降低钢柱的临界温度；破损长度越长、轴向约束刚度越大，临界温度越低。

Critical Temperature of Axially Restrained Steel Columns withPartial Fire Retardant Coating Damage

In order to investigate the fire resistance of steel columns with partial fire retardant coating damage in fire, based on the differential equation of equilibrium on each portion of steel column, the deflection of steel column after the fire retardant coating damage was derived, with the pined ends and rigid ends of the columns at elevated temperatures. The critical temperature calculation method was proposed for partial fire protection damage and axial restrained steel columns by taking the edge yielding criteria. The deflection and axial displacement were verified by finite element method at elevated temperature. With a case study, the critical temperature and relationship of axial force and temperature were obtained for pined column with axial restraint. It was shown that the axial force of the steel column at elevated temperatures was increased and the critical temperature was decreased by the axial restraint. The longer the fire retardant coating damage was and the higher the axial restraint was, the lower the critical temperature was.