跨高速公路曲线钢箱梁顶推施工技术

Incremental Launching Construction Technology of Curved Steel Box Girder Across Expressway

为解决跨高速公路曲线钢箱梁顶推施工难题,结合2×55 m曲线钢箱梁顶推跨越荔玉高速公路施工项目,根据工程概况分析了本项目顶推施工的重难点;阐述了曲线钢箱梁顶推技术,包括顶推施工总体方案、支架设计与计算(包含强度、刚度、稳定性及钢箱梁抗倾覆计算)、钢箱梁加劲肋设置、钢箱梁曲线段纠偏、顶推同步控制、顶推施工监测等。实践表明:采用单向多点顶推、单点主动、多点从动同步控制施工方法,是成功的;曲线钢箱梁顶推,除梁体布设观测点外,还要在支架上布设横向位移观测点,观测点数量不小于梁体观测点的1/3,以保证顶推过程中支架的稳定性。

In order to solve the problem of incremental launching construction of curved steel box girder across expressway, combined with the construction project of 2×55 m curved steel box girder pushing across the Lipu-Yulin Expressway, the difficulties of the incremental launching construction are analyzed according to the project status;the incremental launching technology of curved steel box girder is described, including the overall scheme of incremental launching construction, bracket design and calculation(covering strength, stiffness, stability and anti-overturning calculation of steel box girder), stiffener setting of steel box girder, correction of curve section of steel box girder, synchronous control of pushing, and monitoring of pushing construction. The practice shows that the construction method of one-way multi-point jacking, single point driving, and multi-point driven synchronous control is successful;for the incremental launching of curved steel box girder, in addition to the observation points arranged on the beam body, the lateral displacement observation points should be arranged on the support, and the number of observation points should be controlled more than 1/3 of the observation points of the beam body to ensure the stability of the bracket during the pushing process.