斜拉桥拉索区主梁加固设计

Strengthening Design of the Main Girder in the Cable Zone of a Cable-Stayed Bridge

由于设计时梁体的底板结构过薄,安装应力设计不足导致主梁在15～17号块接缝在施工后续节段时主梁底板和腹板压溃。结合悬臂施工的斜拉桥施工事故处理的工程实例,通过加固方案比选,确定采用在底板与直腹板和底板与斜腹板的隅角处采用外包钢筋混凝土的劲性骨架小纵梁加固方案,实践结果表明采用的加固措施成功解决加固结构与原有结构的结合难题,不损伤原有结构、改善原有结构的受力状态是加固设计的关键。

Owing to the thinness of the designed bottom board structure of the beam body and the insufficiency of the designed erection stress, the bottom board and the web of the main girder crushed at the joints between No. 15 and No. 17 blocks in the later stage of the construction. Considering the engineering examples of the treatment of construction accident of the cantilever-constructed cable-stayed bridge, a strengthening scheme is determined after comparison and selection that uses small stiff framework longitudinal beam with reinforced concrete enclosure in the corners between the bottom board and the vertical web as well as between the bottom board and the inclined web. It is proved by practice that the problem of combination of the strengthening structure and the original structure is successfully solved by this strengthening scheme whose design key is to improve the forced state of the original structure without damaging it.