Unfavorable geometric imperfections in steel plate girders subjected to localized loads
Unfavorable geometric imperfections in steel plate girders subjected to localized loads
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承受局部载荷的钢板梁中不利的几何缺陷
DOI：
10.1016/j.tws.2020.107412
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发表时间：
2021
影响因子：
6.4
通讯作者：
R. Salatić
中科院分区：
文献类型：
--
作者：
S. Kovacevic;N. Marković;D. Sumarac;R. Salatić
最近的试验研究表明，目前的EN 1993 -1-5补丁加载阻力模型低估了极限强度的钢板梁在某些情况下，特别是纵向加劲钢板梁和较长的补丁加载长度。除此抗力模型外，设计标准还允许对极限状态进行有限元分析。现有的设计建议，一个适当的极限状态设计被发现是不够的。本文对钢板梁在局部荷载作用下的缺陷敏感性进行了分析。本文提出了一种非线性有限元参数研究，旨在确定各种几何缺陷的影响，纵向非加劲和加劲钢板梁的补丁负载电阻。实验测得的，屈曲模式仿射，和手工定义的正弦曲线的几何缺陷在研究中结合不同的补丁负载长度和相对刚度的纵向加劲肋。纵向未加劲和加劲钢板梁的极限强度增加补丁负载长度增加的所有考虑的几何缺陷。对于相对较小的贴片荷载长度，纵向加劲肋的相对刚度对极限荷载没有显著影响，无论几何缺陷。对于较长的贴片载荷长度，极限强度高度依赖于几何缺陷。腹板长宽比的影响被证明是可以忽略不计的较小的补丁负载长度无关的几何缺陷，而对于较长的应用程序的负载，此比率的影响是依赖于几何imperfect.Unfavorable几何缺陷钢板梁受到补丁负载的长度和纵向加劲肋的相对刚度。不同的不利几何缺陷被发现为不同的补丁负载长度和相对刚度。定义在上腹板子面板中的局部几何缺陷产生的极限强度低于全局几何缺陷（定义在整个腹板深度上）。对于类似于塌陷时变形的几何缺陷（仿射几何缺陷），返回了最低的贴片载荷阻力。尽管双仿射几何缺陷的概念对于设计目的似乎不切实际（在确定双仿射几何缺陷形状之前，必须进行几何和材料非线性分析），但建议使用这些缺陷形状。
Recent experimental studies have shown that the current EN1993-1-5 patch loading resistance model underestimates the ultimate strength of steel plate girders in certain cases, especially for longitudinally stiffened steel plate girders and longer patch load lengths. In addition to this resistance model, the design standard allows the use of finite element analysis for the ultimate limit state. The existing design recommendations for an adequate ultimate limit state design are found insufficient. In the current paper, the imperfection sensitivity analysis of steel plate girders subjected to patch loading is performed. The paper presents a nonlinear finite element parametric study designed to determine the influence of a variety of geometric imperfections on the patch load resistance of longitudinally unstiffened and stiffened steel plate girders. Experimentally measured, buckling mode-affine, and hand-defined sinusoidal geometric imperfections were varied in the study in combination with varying patch load lengths and relative stiffnesses of the longitudinal stiffener.The ultimate strength of longitudinally unstiffened and stiffened steel plate girders increases as the patch load length is increased for all the geometric imperfections considered. For relatively small patch load lengths, the relative stiffness of the longitudinal stiffener has no significant influence on the ultimate load regardless of the geometric imperfection. For longer patch load lengths, the ultimate strength is highly dependent on geometric imperfections. The influence of the web panel aspect ratio is shown to be negligible for smaller patch load lengths regardless of the geometric imperfection, while for longer applied loads, the impact of this ratio is dependent on the geometric imperfection.Unfavorable geometric imperfections in steel plate girders subjected to patch loading are governed by the patch load length and the relative stiffness of the longitudinal stiffener. Different unfavorable geometric imperfections were found for different patch load lengths and relative stiffnesses. Local geometric imperfections defined in the upper web sub-panel yield lower ultimate strengths than global geometric imperfections (defined over the whole web depth). The lowest patch load resistances were returned for geometric imperfections that resembled the deformation at collapse (collapse-affine geometric imperfections). Although the concept of collapse-affine geometric imperfections seems impractical for design purposes (a geometrically and materially nonlinear analysis must be conducted before collapse-affine geometric imperfection shapes are determined), the use of these imperfection shapes is recommended.