支架整体下放施工技术在双层现浇箱梁中的应用

Application of integral lowering construction technology of support in double-layer cast-in-situ box girder

目前双层现浇箱梁施工顺序多为先上后下模式,其工序环环相扣、互为约束,在搭拆上层支架、安装下层支架时花费时间较长,不利于材料等的周转利用,且支架在拆除期间存在较大安全风险。本文介绍道庆洲大桥双层预应力混凝土现浇接线梁桥建设过程中,在支架主横梁两端通过"千斤顶+高强度精轧螺纹钢"设置吊点,采用整体下放施工方案,只需对管桩进行处理,上层支架体系可全部利用,加快了施工进度、节约了成本,为同类型桥梁上部结构施工提供了借鉴和参考。

At present,the construction sequence of double-layer cast-in-situ box girder is mostly the up-down mode,and its processes are linked and constrained each other.It takes a long time to erect and remove the upper support and install the lower support,which is not conducive to the turnover and utilization of materials,and there are great safety risks during the removal of the support.This paper introduces that during the construction of double-layer prestressed concrete cast-in-situ connection beam bridge of Daoqingzhou Bridge,lifting points are set at both ends of the main beam of the support through"Jack+high-strength finish rolled deformed steel",and the overall lowering construction scheme is adopted.Only the pipe piles need to be treated,and the upper support system can be fully utilized,which speeds up the construction progress and saves the cost,It provides a reference for the superstructure construction of the same type bridge.