飞鸟式拱桥系杆更换与监控技术研究

Research on Replacement and Monitoring Technology of Tie Rods for Fly-Bird-Type Arch Bridges

摘要:

为提高飞鸟式系杆拱桥系杆换索效率，采用改进新增系杆法对中山二桥进行系杆更换。施工采用“边剪切边张拉”的施工工艺，对旧系杆分级剪断、新系杆分级张拉依照横向对称且拱肋两侧对称进行，分10级按每级10%索力进行张拉，每级张拉切断旧系杆10%面积的钢绞线。成桥后对系杆索力进行整体校准，完成体系转化。同时基于MIDAS Civil软件建立桥梁有限元模型，对锚箱结构优化、体系转换施工工艺、结构受力监控和断索工序进行仿真分析。研究表明，系杆更换过程中实测索力与施工组织设计吻合，施工过程安全可控；该系杆更换和监控技术体系可以方便地应用于既有飞鸟式拱桥的改造和加固施工中，并具备良好的经济性和社会效益。

Abstract:

In order to enhance the efficiency of tie rod replacement for fly-bird-type arch bridges, the tie rods of Zhongshan Bridge II are replaced by the improved and newly added tie rod method. The technology of “shearing and tensioning simultaneously” is used in the construction. The old tie rods are cut in grades and the new tie rods are tensioned in grades in accordance with the transverse symmetry and the symmetry on both sides of the arch ribs. Tensioning is carried out in 10 levels, with 10% of the cable force at each level. Tensioning at each level cuts the steel strands within 10% of the area of the old tie rods. After the bridge is completed, the force of the tie rod cables is calibrated as a whole to complete the system transformation. At the same time, based on MIDAS Civil software, the finite element model of bridge is established to simulate and analyze the anchor box structure optimization, system conversion construction technology, structural force monitoring and cable breaking. The study result shows that the measured cable force during the replacement of the tie rods is consistent with the construction organization design. The construction process is safe and controllable. This tie rod replacement and monitoring technical system can be conveniently applied in the reconstruction and reinforcing construction of existing fly-bird-type arch bridges, and has the good economy and social benefits.