Abstract Eccentric vertical loads acting on bridge girders induce distortion of the cross-section of the steel box girder, which causes distortional warping normal stress at the flange and web of the box section in a longitudinal direction. Recent design standards specify that intermediate diaphragms, which prevent deformation of the box section, need to be installed to control these distortional warping normal stresses. In addition, the maximum ratio requirements between distortional warping normal stress and bending normal stress should not exceed 5 and 10%, respectively. However, the design standards do not provide specific formulae for use in determining the appropriate intermediate diaphragm spacing; therefore, an accurate structural analysis is required from the design stage and the iterative structural analysis time-consuming. In this study, to simplify the structural analysis steps required in the design phase, a parametric study was conducted using 3D finite element analysis (FEA) to estimate the intermediate diaphragm spacing required for composite simple span single-cell box girder bridges. In the parametric study, the box girder bridges were modeled using actual bridge data relating to the cross-sectional aspect ratio, span length, and flange thickness. The FEA results show that the coupling effects of the cross-sectional aspect ratio, the ratio of the distortional warping constant to the moment of inertia, span length, and eccentricity, have a significant effect on the diaphragm spacing and normal stress ratio. Based on these FEA results, efficient intermediate diaphragm spacing was determined in consideration of the cross-sectional aspect ratio, span length, and flange thickness.

中文翻译：

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考虑纵横比的单室矩形钢箱梁桥中间隔板间距

摘要 作用在桥梁上的偏心竖向荷载引起钢箱梁横截面的变形，从而在箱形截面的翼缘和腹板上产生纵向扭曲翘曲法向应力。最近的设计标准规定，需要安装防止箱形截面变形的中间隔膜，以控制这些扭曲翘曲的法向应力。此外，扭曲翘曲法向应力与弯曲法向应力的最大比值要求分别不应超过5%和10%。但是，设计标准没有提供用于确定适当的中间膜片间距的具体公式；因此，从设计阶段就需要进行准确的结构分析，而迭代结构分析非常耗时。在这项研究中，为了简化设计阶段所需的结构分析步骤，使用 3D 有限元分析 (FEA) 进行了参数化研究，以估算组合简单跨度单室箱梁桥所需的中间隔板间距。在参数化研究中，箱梁桥使用与横截面纵横比、跨度长度和翼缘厚度相关的实际桥梁数据进行建模。有限元分析结果表明，截面纵横比、扭曲翘曲常数与转动惯量之比、跨度长度和偏心距的耦合效应对膜片间距和法向应力比有显着影响。基于这些 FEA 结果，考虑到横截面纵横比、跨度长度、