大挑臂复合截面节段梁总体设计研究

Research on Overall Design of Large-cantilever Composite Cross-sectional Segment Beam

摘要:

为解决宽桥面节段梁运输吊装困难、传统多箱断面施工复杂等问题，提出了大挑臂复合截面节段梁结构。该设计将整体断面分解成预制核心箱梁与后装挑臂两部分，采用“核心先行、挑臂后装”的分阶段施工方法；同时通过系统参数分析，明确了该结构在40~70 m跨径的适用性，确定双6车道断面为最优方案，并建立了基于墩高与跨径组合的结构体系选用准则。有限元精细化分析结果表明：大挑臂复合截面节段梁在偏载等关键工况下受力性能良好，其截面尺寸仍具优化潜力；采用该结构可显著降低核心梁段吊重，减少大型设备投入，为宽桥面桥梁的工业化建设提供了一种有效的轻量化解决方案。

Abstract:

To address the challenges of transporting and hoisting wide-deck segment beams and the construction complexity of traditional multi-cell sections, a large-cantilever composite cross-sectional segment beam structure is proposed. In this design, the overall cross-section is divided into two parts of precast core box girder and post-installed cantilevers, and the phased construction method of “core girder first, cantilevers second” is adopted. Through systematic parameter analysis, the applicability of the structure within the 40-70 m span range is clarified, the dual six-lane cross-section is identified as the optimal scheme, and a criterion selected for structural systems based on pier height and span combination is established. The results from refined finite element analysis demonstrate that the large-cantilever composite cross-sectional segment beam has good mechanical performance under key working conditions such as eccentric loading, and its cross-sectional dimensions still have potential for optimization. The use of this structure can greatly reduce the hoisting weight of core girders, and decrease the investment of large-sized equipment, which provides an effective lightweight solution for the industrialized construction of wide-deck bridges.