异型单肋双索面人行钢拱桥吊杆张拉方案研究

Analysis of Tensioning Scheme for Suspenders of Special-shaped Steel Arch Pedestrain Bridge with a Rib and Double Cable Planes

为实现异型人行拱桥梁施工各阶段合理受力状态,需探索合理的吊杆张拉方案。以云溪桥-异型单肋双索面人行钢拱桥为研究对象,根据桥梁自身特点确定出吊杆张拉方案的合理性原则和多种吊杆张拉方案,建立桥梁有限元模型进行桥梁施工阶段分析,采用正装迭代法得到各施工阶段的吊杆张拉控制力,探讨多种吊杆张拉方案对桥梁主要构件施工阶段受力及变形的影响。结果表明:从拱肋受力与变形角度来看,从两边拱脚向中间拱顶顺序张拉吊杆方案对桥梁结构更有利;初始张拉双根吊杆措施更适合从中间拱顶向两边拱脚顺序张拉吊杆;同时张拉内外侧吊杆比先张拉外侧吊杆后张拉内侧吊杆更有利于拱肋、主梁受力与变形;双批次先外侧后内侧张拉吊杆使主要受力构件应力及变形峰值更小、变化过渡更为平缓,优于单批次内外侧同时张拉吊杆方案。桥梁内侧吊杆设计索力较小,不宜分批次张拉,外侧吊杆设计索力稍大,可进行二批次吊杆张拉。

It is necessary to explore a reasonable suspender tension scheme for special-shaped pedestrian arch bridges to achieve a reasonable stress state at each stage of bridge construction.The Yunxi bridge is taken as an research ob-ject,which is a special-shaped steel arch pedestrian bridge with a rib and double cable planes.The principles of the tensioning schemes for suspenders are determined,as well as the different tensioning schemes for suspenders based on the inherent characteristics of the bridge.The finite element model of the bridge is established,and the construction stages analysis of the bridge is conducted to explore the impact of various tensioning schemes for suspenders on the stresses and deformations of the main components of bridge during the construction stages.The tension control forces of the suspenders at each construction stage are obtained by the forward iteration method.The results show that from the perspective of forces and deformations of arch rib,the tensioning schemes of suspenders from both arch ends to the middle of the arch rib are more beneficial to the bridge structure.The measurement of initial tensioning double sus-penders is more suitable for the schemes of tensioning suspenders from the middle of arch rib to both arch ends.Fur-thermore,the scheme of tensioning the inner and outer suspenders simultaneously is more conducive to the stress and deformation of the arch rib and main girder than the scheme of tensioning the outer suspenders first and then the inner suspenders.Additionally,the scheme of tensioning outer suspenders first and then inner suspenders with double bat-ches reduces the peak stresses and deformations of the main components and makes the transition of changes smoother,which is better than the schemes of tensioning inner and outer suspenders simultaneously with single batch.Notably,the design cable forces of the inner suspenders are relatively smaller and should not be tensioned in batches,while the design cable forces of the outer suspenders are slightly larger,and can be tensioned in two batches.