外伸翼缘加劲钢箱形压弯构件屈曲特性试验

为了研究Q500qE高性能钢外伸翼缘薄壁加劲箱形压弯构件的稳定特性，开展3个Q500qE和1个Q345B的构件模型试验，分析试验构件的荷载-位移曲线、整体和局部屈曲形态.整体屈曲试验结果表明，采用Q500qE高性能钢和设置外伸翼缘可以有效提高薄壁箱形压弯构件极限承载力且能够改善构件整体稳定特性.局部屈曲试验表明，外伸翼缘宽厚比对平面外局部屈曲半波数和局部变位影响较大，故需要根据现有规范中的宽厚比限值要求限制外伸翼缘板局部屈曲.对于构件的极限承载力和屈曲形态，试验结果与弹塑性数值分析结果吻合较好.分别采用允许应力法和极限状态法对Q500qE构件进行稳定验算，与试验结果进行比较，表明现有规范中的相关验算公式适用于验算此类压弯构件.

Experimental investigation on buckling behavior of stiffened steel box-section beam-column with external flanges

In order to investigate the stability of stiffened steel thin-walled box-section (SSTB) beam-column members with extended flanges made of the high-performance steel (HPS) Q500qE, three Q500qE and one Q345B member model tests were conducted to analyze the load-displacement curve, the global and local buckling behavior of the test members. The results of the global buckling test show that, by using the HPS Q500qE and setting the extended flanges, the ultimate bearing capacity of the SSTB members can be effectively increased and the overall stability of the components can be improved. However, the local buckling tests show that the numbers of half waves and the local deformation in the out-of-plane direction are greatly affected by the width-to-thickness ratio of extended flanges, so the local buckling of the extended flanges need to be limited by the width-to-thickness ratio in accordance with current design codes. The ultimate loads and buckling behaviors obtained from theelasto-plastic numerical analysis conform well with the results of the model tests. At last, the allowable stress method and the limit state method are applied respectively to validate the stability of such members made of Q500qE, and compared with model tests as well. It shows that the stability equations in current codes can be suitable for such members made of Q500qE.