基于钢门式墩的现浇梁侧位横移力学性能研究

Research on Mechanical Performance of Lateral Movement of Cast-in-Situ Beam Based on Steel Portal Pier

新建赣深高铁某特大桥为单线32 m简支梁桥,通过钢门式墩小角度跨越既有高铁线路,施工中采用侧位现浇、张拉脱模后整体横移顶推施工就位。为探讨侧位现浇梁横移顶推施工过程中安全性,利用有限元软件对简支梁横移过程中滑道梁、钢管立柱和钢盖梁等构件的力学性能开展了研究,并对滑道梁-门式墩过渡段连接构造进行了优化。结果表明:滑道梁、钢管立柱和钢盖梁在侧位横移初期应力较大,施工时应重点关注;在侧位横移过程中,滑道梁、钢管立柱和钢盖梁的应力和挠度均满足相关规范要求;综合考虑适用性和经济性,在钢管立柱-门式墩过渡段宜设置2片厚1 cm的加劲板实现滑道梁刚度的均匀过渡。

The certain bridge of the new Ganzhou-Shenzhen High-speed Railway is a 32 m simply supported beam bridge with a single track, which crosses the existing railway at a relatively small angle based on the steel portal piers. The bridge is completed by laterally pushing the cast-in-situ beam when the prestresed steel bars in the beam were tensioned. To discuss the safety of the cast-in-place beam during the pushing process, the finite element software was used to analyze the mechanical properties of the slideway, steel tube column and steel capping beam during the lateral pushing, and the connection part between the slideway and steel portal pier was optimized. The results show that, the initial stress of the slideway, steel tube column and steel capping beam is relatively large, and the phenomenon should be emphasized;the stress and deflection of the slideway, steel tube column and steel capping beam can satisfy the code requirement during the pushing;comprehensively considering applicability and economy, two stiffening plates with a thickness of 1 cm are recommended to install in the transition part between the steel tube column and steel portal pier to realize a uniform transition of the slideway rigidity.