大跨分离式钢箱梁设计要点研究

Research on Key Design Points of Long-span Separated Steel Box Beams

摘要:

为适配交通基础设施大跨度、高标准建设需求，结合钢结构桥梁跨越能力强、工业化程度高、施工周期短的优势，依托深圳市72 m+118 m+72 m变截面连续钢箱梁桥工程，开展设计要点与关键技术研究。通过阐述项目背景、工程概况及三箱单室分离式断面总体设计构思，聚焦钢结构局部稳定控制核心问题，完成刚性加劲肋选型设计与验算，定量计算顶底板受压区局部稳定折减系数及剪力滞效应影响值；针对中支点高腹板受力复杂特性，优化纵横向加劲肋布置方案并开展力学效应分析与稳定验算；探讨正交异性桥面板疲劳破坏机制，分析板件连接方式对疲劳性能的影响并完成多模型疲劳验算。研究成果为同类大跨度连续钢箱梁桥设计提供技术参考，保障结构安全与工程适用性。

Abstract:

To meet the requirements of long-span and high-standard construction of transportation infrastructure, combined with the advantages of steel structure bridges such as strong spanning capacity, high industrialization level and short construction period, and relying on a 72 m+118 m+72 m variable-section continuous steel box beam bridge project in Shenzhen, the key design points and key technologies are studied. By elaborating the project background, engineering overview, and the overall design concept of the three-box single-cell separated cross-section, and focusing on the core issue of local stability control of steel structures, the selection design and verification of rigid ribbed stiffeners are completed, and the local stability reduction coefficient of the compressed zones of the top and bottom plates as well as the influence value of the shear lag effect are quantitatively calculated. Aiming at the complex stress characteristics of the high web plate at the middle support, the layout scheme of longitudinal and transverse ribbed stiffeners is optimized, and its mechanical effect analysis and stability verification are conducted. Additionally, the fatigue failure mechanism of the orthotropic deck is discussed, the influence of plate connection methods on fatigue performance is analyzed, and the multi-model fatigue verification is completed. The research results provide the technical references for the design of similar long-span continuous steel box beam bridges, ensuring the structural safety and engineering applicability.