城际铁路先梁后拱法系杆拱桥施工监控技术研究

Study of the Monitoring of Intercity Railway Tied Arch Bridge with Beam-First-and-Arch Construction Craft

以某城际铁路1-96 m系杆拱桥施工项目为依托,提出一套经济高效的施工方案。基于系统化的监测技术,实现对该桥施工过程中系梁、拱肋、支架、吊杆等关键结构的应力和变形监测;建立有限元计算模型,对桥梁进行全施工阶段仿真模拟,并将仿真计算理论值与实测值进行对比分析。研究表明,成桥状态下系梁跨中位置累积沉降最大,为5 mm,轴线偏位最大为1.5 mm,临时支架最大横向位移为5 mm,全桥线形控制良好,满足设计要求。应力监测表明,拱肋混凝土压注完成后,应力达到最大值,系梁应力则相对减小,随后系梁、拱肋协调变形,内力重新分布;吊杆第一次张拉后,两端吊杆受力较大,中间偏小。第二次张拉后,全桥索力均匀分布,与设计值偏差均小于5%。

Taking an 1-96 m intercity railway tied arch bridge as an example,an economic and efficient construction scheme was developed.Systematic monitoring techniques enabled engineers to obtain stresses and deformations of the bridge.A finite element model was established in this paper to simulate the construction process,and the results from numerical simulation were compared with field measurement.Under completion state,the maximum cumulative settlement of the tie beam was 5 mm,which occured at mid-span.The maximum axial deflection was 1.5 mm,the maximum lateral displacement of the temporary supports was 5 mm.The results shows that the geometry control is effective.As the rib pressure-grouted concrete engineering is finished,the stress reaches its maximum while the tie beam stress decreases slightly.The coordinate deformation between tie beam and arch rib causes redistribution of the internal stresses.After the first tensioning of the bridge,the suspender forces at both ends are higher than at center.After the second tensioning,the suspender force is uniformly distributed with error less than 5%.