不同等级高强钢焊接工形轴压柱整体稳定性能及设计方法研究

Overall buckling behavior and design method for axially compressed welded I-sectional columns constructed with different grades of high-strength steels

为研究460MPa以上不同强度等级高强钢焊接工字形截面轴压柱的整体稳定性能,采用有限元分析方法,计算了国内外已公开发表（包括其他学者）的35个高强钢焊接工形试件的整体稳定承载力,并通过与试验结果对比验证了有限元模型的可靠性;利用该模型完成1280个算例的整体稳定承载力计算,包括8种钢材强度等级、8种工字形截面尺寸、对应于每种截面的10种长细比、以及绕截面强轴和弱轴失稳的2种模态,并将算例结果与现行钢结构设计规范的设计曲线进行对比分析。研究结果表明,随着钢材强度等级的提高,高强钢焊接工字形截面轴压构件绕强轴和弱轴失稳的整体稳定系数均明显提高;对于绕强轴失稳构件,建议Q460-Q550钢材的采用我国规范b类曲线,Q620-Q960钢材的采用a类曲线;对于绕弱轴失稳构件,建议Q460-Q800钢材的按b类曲线设计,Q890和Q960钢材的按a类曲线设计。此外,还提出此类构件对应不同强度等级钢材的更新柱子曲线公式,以更准确计算其整体稳定承载力。

To investigate the overall buckling behavior of axially compressed welded I-sectional columns constructed with different grades of high-strength steels （ HSS ） , the overall bearing capacities of 35 high-strength welded I-sectional specimens reported in the literatures are calculated by using the finite element analyzing method. By comparing with the experimental results, the reliability of the finite element model is validated. Based on the finite element model, the overall bearing capacities of 1280 pin-ended column specimens are computed, and among the column specimens, there are eight grades of steels, eight welded I-sections, ten slenderness ratios for each section, and two buckling modes about the major and minor sectional principal axes. Furthermore, the finite element analysis results are compared with design curves according to the national standard GB 50017--2003. It is found that the overall buckling strength of HSS welded I-sectional columns around both sectional principal axes can be markedly improved, which results from the increase of steel grade. For those HSS welded I-sectional columns buckling around the major axis, it is recommended to apply the column curve of type b in GB 50017--2003 to Q460 - Q550 steels, and the curve of type a to Q620 - Q960 steels. While for those members buckling around the minor axis, it is suggested to apply the curve of type b to Q460 - Q800 steel columns and the curve of type a to Q890 or Q960 steel. Additionally, an alternative design methodology is proposed for the prediction of overall buckling strength of welded I-section columns with varying grades of HSS in terms of renewed column curves.