高温下轴心受压高强Q690钢柱的局部稳定

Local Bucking of Q690 High-Strength Steel Columns Subjected to Axial Compression at Elevated Temperature

现行《建筑钢结构防火技术规范》(GB 51249—2017)未给出火灾下钢结构的局部稳定设计方法,为了获得轴心受压焊接H形高强Q690钢柱高温下的局部稳定性能,考虑钢材高温下力学性能退化、截面高温下焊接残余应力降低及初始几何缺陷,采用ABAQUS软件建立经试验验证的高温局部稳定分析有限元模型,得到焊接H形高强Q690钢柱在不同温度下的局部屈曲应力和极限应力。研究表明:当温度低于550℃时,钢柱在高温下和常温下屈曲应力具有相同的变化趋势;高温下的残余应力值和初始几何缺陷对屈曲应力有较大的影响,但对极限应力影响较小。

The current Code for Fire Safety of Steel Structures in Buildings(GB 51249—2017)does not include local buckling design method of components in fire.In order to obtain local stability performance of H-shaped high-strength Q690 steel column under axial compression at elevated temperature,a finite element model to analyze high temperature local stability by using ABAQUS software,and the local residual buckling stress and ultimate stress at high temperature are obtained.This method accounts for the deterioration of mechanical properties,reduction of welding residual stress at high temperature,and initial geometric imperfection.These results indicate when the temperature is less than 550 ℃,the trend of buckling stress at elevated temperature is similar to that at room temperature.The residual stress and initial geometric imperfection have obvious effect on buckling stress but little effect on the ultimate stress.