阜溧高速软基区现浇混凝土曲线梁线形控制

Alignment Control of Cast-in-situ Concrete Curved Beams in Soft Foundation Area of Fuli Expressway

软基区域的现浇混凝土曲线梁在施工时面临着地基承载力弱、不可控因素多、成桥线形控制难度大等问题。以阜溧高速公路大纵湖互通C匝道桥现浇混凝土曲线梁工程为依托,提出了桥梁施工区域软基的加固措施,采用有限元软件Midas Civil建立了曲线梁模型,分析了曲线梁竖向和径向位移的变化规律和影响因素,提出了曲线梁线形控制的施工措施。结果表明:收缩徐变、预应力、恒载引起的预应力连续箱梁最大挠度值分别为2、13、12.5 mm,在混凝土弹性模量、容重和预应力改变时,预应力改变对挠度影响最大;曲线梁平面径向位移对温度作用较敏感,系统升温引起的径向位移达到了14.11 mm。对箱梁开展监测,结果表明该混凝土箱梁高程偏差满足规范要求,且监测结果与有限元模拟值较吻合,研究结果可为类似工程提供借鉴。

The construction of cast-in-place concrete curved beams in the soft foundation area faces problems such as weak foundation bearing capacity,many uncontrollable factors,and difficulty in controlling the alignment of the bridge.Relying on the cast-inplace concrete curve beam project of the Dazong Lake Interchange C ramp bridge of Fuli Expressway,the reinforcement measures for the soft foundation in the bridge construction area were proposed.The curved beam model was established through the finite element software Midas Civil,the changing rules and influencing factors of the vertical and radial displacements of the curved beam were analyzed,and construction measures for linear control of curved beams were proposed.The results show that the maximum deflection of prestressed continuous box girder caused by shrinkage creep,prestress and dead load is 2 mm,13 mm and 12.5 mm respectively,the change in prestress has the greatest influence.The plane radial displacement of the curved beam is more sensitive to the temperature effect,and the radial displacement caused by the system temperature rise reaches 14.11 mm.The monitoring of the box girder shows that the elevation deviation of the concrete box girder meets the specification requirements,and the monitoring results are in good agreement with the finite element simulation values.The research results can provide reference for similar projects.