钢筋混凝土系杆拱桥吊杆更换施工监控

Construction Supervision of Suspender Replacement of Reinforced Concrete Bowstring Arch Bridge

摘要:

朱家坞公路桥主桥跨径为65 m下承式钢筋混凝土系杆拱桥，拱肋采用钢筋混凝土矩形截面，全桥共24根吊杆，吊杆接近设计使用寿命且出现严重病害，需要对其进行更换。利用MIDAS Civil软件构建了桥梁的有限元分析模型，并进行吊杆替换工程的模拟评估，为吊杆更换提供目标索力和桥面标高参考值。在吊杆更换过程中，对吊杆索力、主拱结构应力及变形进行监控。结果表明，吊杆更换后主拱结构的应力分布、桥面及拱肋线形等与更换前的状态基本一致，吊杆索力与目标索力的偏差满足桥梁设计规范要求。可以提供针对类似桥梁的监控施工过程中的吊杆更换案例参考。

Abstract:

The main bridge of the Zhujiawu Bridge is a reinforced concrete through bowstring arch bridge with span of 65 m. The cross sections of the arch ribs are the reinforced concrete rectangular sections. There are totally 24 suspenders of the whole bridge. The suspenders are close to the design service life and are seriously corroded. It is necessary to replace the suspenders of the bridge. The software MIDAS Civil is used to establish the finite element model of the bridge. The replacement engineering of the suspenders is simulated and evaluated. The reference values of target cable force and deck elevation are provided for the replacement of suspenders. In the process of suspender replacement, the suspender cable force, and the structural stress and deformation of the main arch are monitored. The results show that the stress distribution of the main arch structure, the bridge deck and the arch rib alignment after the suspender replacement are basically consistent with those before the replacement. The deviation between the suspender cable force and the target cable force meets the requirements of the bridge design specifications, which can provide the reference for the construction monitoring of the suspender replacement in the similar bridge projects.