弯剪共同作用下不锈钢薄腹梁承载性能试验研究

Experimental study on stainless steel plate girders subjected to bending and shear interaction

为研究不锈钢薄腹梁在弯矩和剪力共同作用下的承载性能,进行了6根焊接工字形截面不锈钢梁的试验研究。结果表明,所有梁试件的破坏形态为结合了腹板剪切屈曲和受压区板件局部鼓曲的弯剪联合屈曲。建立精细有限元数值模型对试验过程进行模拟,同时考虑了不锈钢材料、几何双非线性,局部几何初始缺陷和焊接残余应力的影响。基于得出的试验和有限元分析结果,对我国《钢结构设计标准》(GB 50017—2017)中考虑腹板屈曲后强度的梁弯剪相关计算方法进行评估。分析表明:当梁的极限承载力受剪切控制时,腹板正则化宽厚比较大时的规范计算承载力偏于保守,而正则化宽厚比较小时的计算承载力与试验和有限元分析结果较为接近;当梁的极限承载力由弯剪共同作用控制时,规范中公式的承载力计算值偏于安全。总体而言,GB 50017—2017的计算方法可以直接应用于计算不锈钢焊接截面梁在弯剪共同作用下的极限承载力。

To study the load-carrying capacities of stainless steel plate girders under bending and shear(M-V)interaction,six welded stainless steel plate girders were tested.The failure modes of all test specimens appear to be the shear buckling in the web panel and the local compression buckling in both the web and the upper flange.Furthermore,the experimental tests were simulated by refined finite element(FE)models in consideration of the material and geometric nonlinearities,the initial local geometric imperfections and the welding residual stresses.Based on the test and FE results,the M-V design provisions for the post-buckling capacities of web panels,which are specified in the Chinese standard‘Standard for design of steel structures(GB 50017—2017)’,were evaluated.The analysis results revealed that:when the ultimate load-carrying capacity of girder is dominated by shear buckling,the capacity predicted by the Standard is relatively conservative if the regularized width-to-thickness ratio of the web is large;while that predicted by the Standard agrees well with the test and FE results if the regularized width-to-thickness ratio of the web is small.When the ultimate load-carrying capacity of girder is dominated by the combined bending and shear buckling,the capacity predicted by the Standard is relatively safe.Generally,it can be concluded that the calculation method in the Standard of GB 50017—2017 may be directly applied to the ultimate load-carrying capacity of stainless steel plate girders under the combined bending and shear.