小半径高、宽渐变钢箱梁跨高速公路顶推方案研究

Study on Incremental Launching Scheme of Small-radius High and Wide Gradient Steel Box Girder across Freeway

摘要:

上跨现状高速公路常采用顶推法施工，对于小半径高、宽渐变钢箱梁传统做法采用曲线顶推方案，传统做法存在顶推工艺复杂、技术难度大、工期长、下部结构造价高等问题，应用范围有限。以白云五线匝道主桥上跨广清高速钢箱梁为工程背景，详细分析小半径高、宽渐变钢箱梁结构特点，提出变宽曲梁直顶的新方案，同时根据顶推梁变宽特点，对墩顶垫梁宽度进行合理布置，以满足受力明确和减少用钢的设计要求。对钢箱梁在顶推过程各工况的受力进行分析，验证顶推方案的合理性。曲梁直顶很好的环境适应性、工期短、受力明确和良好的经济性，可为同类型顶推方案提供参考。

Abstract:

The incremental launching method is commonly used for the construction across the existing freeways. For small-radius high and wide gradient steel box girders, the traditional method is to use the curved incremental launching scheme. The traditional method has the problems such as complex process, large technical difficulty, long construction period, and high cost of the substructure. And its application scope is limited. Taking the steel box girder of the ramp bridge spanning Guangqing Expressway in Baiyun Line V as the engineering background, the structural characteristics of the small-radius high and wide gradient steel box girder are analyzed in detail, and a new scheme of direct incremental launching of widening curved girder is proposed. The width of the pier top bearing beam is reasonably arranged according to the widening characteristics of the incremental launched girder in order to meet the design requirements of clear stress and reduced steel consumption. The stress of the steel box girder under various working conditions during the incremental launching process is analyzed to verify the rationality of the incremental launching scheme. The direct incremental launching of curved girder has good environmental adaptability, short construction period, clear stress and good economy, which can provide reference for similar incremental launching schemes.