公路旧桥提质改造方案研究——以呼和浩特市浑河大桥为例

Research on the Quality Improvement and Renovation Plan for Old Highway Bridges -Taking the Hunhe River Bridge in Hohhot as an Example

摘要:

为解决早期公路桥梁老化严重、荷载等级不足及原始资料缺失等问题，以呼和浩特市S237浑河大桥改建工程为背景，研究“上部结构损坏严重、下部结构相对完好”型危桥的提质改造策略。首先，基于检测评估结果，确定了“拆除危旧上部结构和桥台，修复并利用现有桥墩，两端各延长1跨，新建轻型桥台，全桥更换为承载力更强、自重更轻的上部结构”的总体改建方案；其次，对不同上部结构方案进行综合比选，结果表明组合钢板梁方案较预应力空心板梁方案恒载降低约47%，总重下降约24%，可有效化解荷载标准由“汽车—20级”提升至“公路—Ⅰ级”对下部结构承载力的挑战；最后，详细阐述了结构设计要点、桥墩修复方法和装配化施工流程。工程实践结果表明，浑河大桥总体改建方案可安全高效地提升桥梁承载能力，充分利用旧桥资源，实现快速化改造，为同类工程提供可靠技术参考。

Abstract:

To address issues such as severe aging, insufficient load rating, and missing original data of early highway bridges, the study focuses on the upgrading strategy for dangerous bridges with "severely damaged superstructures and relatively intact substructures," taking the reconstruction project of the Hunhe River Bridge on S237 in Hohhot as the background. Firstly, based on the inspection and evaluation results, an overall reconstruction plan has been determined, which involves "demolishing the dangerous old superstructure and abutments, repairing and utilizing the existing piers, extending one span at each end, constructing new lightweight abutments, and replacing the entire bridge with a superstructure with stronger bearing capacity and lighter self-weight." Secondly, a comprehensive comparison of different superstructure schemes reveals that the composite steel plate girder scheme reduces dead load by approximately 47% and total weight by approximately 24% compared to the prestressed hollow slab girder scheme. This effectively addresses the challenge posed by the increase in load standard from "Truck-20" to "Highway- I" on the substructure's bearing capacity. Finally, the key points of structural design, pier repair methods, and prefabricated construction processes are elaborated. The practical engineering results demonstrate that the overall reconstruction plan for the Hunhe River Bridge can safely and efficiently enhance the bridge's bearing capacity, fully utilize old bridge resources, achieve rapid transformation, and provide a reliable technical reference for similar projects.