云南庄特大桥三角区施工方案

云南庄特大桥主桥为(150+280+150)m预应力空腹式连续刚构桥。主梁根部三角区分为空腹区和汇合区,总长约134 m,三角区结构受力复杂,施工难度大,工期紧,通过方案比选确定三角区采用斜拉扣挂辅助悬臂浇筑施工方案。上、下弦节段通过张拉临时扣索作为节段的支撑结构,利用挂篮分别悬浇上、下弦节段。上、下弦合龙前先拆除下弦挂篮部分结构,仅用上弦挂篮施工汇合区节段混凝土。该方案能有效避免上、下弦施工互相干扰,有利于工期控制及质量保证。利用MIDAS Civil软件对三角区施工方案进行受力分析,计算结果满足要求。

Construction Schemes for Triangle Zone of Yunnanzhuang Bridge

The main bridge of Yunnanzhuang Bridge is a prestressed concrete open-web continuous rigid-frame bridge with a main span of 280 m and two side spans of 150 m.The triangle zone over main pier consists of the open web section and the converging section,with a total length of 134 m.Due to that the load bearing behavior of the triangle zone is complicated,the construction work is daunting and the construction schedule is tight,a cable-stayed cantilever casting solution is selected.Temporary fastening stays were tensioned to support the upper and lower chord segments,and form travelers were used for segments concreting.Before the closure of the upper and lower chords,a portion of the form traveler of the lower chord was demolished,where the form traveler of the upper chord was left for the casting of the converging section.The proposed solution precludes the reciprocal interruption of the castings of the upper and lower chords,and is beneficial to construction schedule and quality control.The load bearing conditions of the triangle zone construction solution were analyzed by using software MIDAS Civil,and the calculation results met the requirements.