不锈钢薄腹梁受剪性能试验研究

通过对7根不锈钢薄腹梁进行受剪性能试验研究，分析了梁腹板的剪切屈曲和屈曲后强度。结果表明：所有梁均发生剪切屈曲破坏，薄腹板中形成拉力带，上翼缘和横向加劲肋中出现塑性铰；根据腹板表面应变和侧向鼓曲变形测得的剪切屈曲应力均低于理论计算的弹性剪切屈曲应力；梁的受剪承载力显著高于腹板剪切屈曲时的荷载，具有较高的屈曲后强度；梁端设置封头肋板可以提高梁的受剪承载力。基于得出的试验结果及现有其他试验数据，对两种考虑腹板屈曲后强度的受剪承载力计算方法进行评估，我国GB 50017—2017《钢结构设计标准》中的公式仅考虑了腹板的受剪承载力，其计算结果总体偏于保守，但是对腹板高厚比较小(λs<1.5)的不锈钢薄腹梁，受剪承载力计算偏于不安全，且计算结果离散性较大；EN 1993-1-4中的计算公式中同时考虑了腹板和翼缘的受剪承载力，其计算结果偏于保守且离散性较小。

Experimental study on shear behavior of stainless steel plate girders

Shear tests on seven stainless steel plate girders were carried out to investigate the critical shear buckling and post-buckling behavior of stainless steel web panels. It is indicated that all the tested plate girders fail by shear buckling with a tension band developed in each web panel and plastic hinges formed at the top flange and transverse stiffener. The critical shear buckling stresses, determined by the recorded surface strains and lateral deformations of the web panels, are lower than the corresponding theoretical elastic solutions. Meanwhile, the ultimate shear resistances of the girders are considerably higher than the critical shear buckling stresses of the web panels, indicating a substantial amount of post-buckling strength for each test specimen. Moreover, the introduction of rigid end posts results in a noticeable increase in the ultimate shear resistance. The obtained test results, together with other existing test data, were summarized to evaluate two current design methods that take into account the post-buckling resistances of web panels. Due to the inclusion of web contribution only, the design provisions in the Chinese standard for design of steel structures GB 50017—2017 provide generally conservative strength predictions, yet slightly overpredicted resistances for specimens with relatively small web slenderness (λs <1.5) with relatively large scatter. Meanwhile, the ultimate shear resistances predicted by EN 1993-1-4, involving contributions from both the web and the flanges, are generally conservative compared to the test data but with reduced scatter.