不等跨现浇箱梁中墩梁固结的预应力隐形盖梁的设计分析

Design Analysis of the Pier Girder Consolidation Concealed Bent Cap of Unequal Span Cast-in-situ Box Girder

针对上跨地方道路的高架桥净空受限的问题,可采用不等跨的上部箱梁结合隐形盖梁的结构形式可适应复杂的地面道路,节省桥下空间,解决桥下净空受限的问题。现采用midas Civil有限元软件建模分析隐形盖梁模型。分析结果表明:对于长宽比小于4的桥梁,需正确计入剪力滞引起的有效宽度折减;支点顶部空间受限时可将横向钢束上抬至同一高度,张拉方式调整为单侧张拉。对同类桥梁的设计具有较好的参考意义。

In view of the limited headroom of viaducts crossing ground roads,the structural form of unequal span upper box girder combined with invisible bent cap can be used to adapt to complex ground roads,save space under the bridge and solve the problem of limited clearance under the bridge.Using midas Civil finite element software to model and analyze.The analysis results show that:For bridges with length width ratio less than 4,the effective width reduction caused by shear lag should be correctly included;When the space at the top of the fulcrum is limited,the transverse steel tendon can be lifted to the same height,and the tensioning method is adjusted to unilateral tensioning.It has good reference significance for the design of similar bridges.