上跨既有线斜腿刚构桥无平衡索整体顶升关键技术  

Integral Jack-Up Technique for a Slant Legged Rigid Frame Bridge Crossing an Existing Railway Without Using Balanced Cables

作　　者：程海根[1] 蔡慧芳 曾辉 邹常进 CHENG Haigen;CAI Huifang;ZENG Hui;ZOU Changjin(School of Civil Engineering and Architecture,East China Jiaotong University,Nanchang 330013,China;Shanghai Xianke Bridge and Tunnel Detection and Reinforcement Engineering Technology Co.,Ltd.,Shanghai 200070,China)

机构地区：[1]华东交通大学土木建筑学院,江西南昌330013 [2]上海先科桥梁隧道检测加固工程技术有限公司,上海200070

出　　处：《桥梁建设》2023年第5期138-144,共7页Bridge Construction

基　　金：江西省研究生创新资金项目(YC2022-s507)。

摘　　要：襄荆高速公路某跨线天桥为跨径52.78 m的斜腿刚构桥,为满足净空要求,需将全桥整体顶升抬高60 cm以上。结合该桥特点,在满足不中断交通的要求下,通过方案比选采用无平衡索整体同步顶升方案。该方案通过在斜腿根部设置自平衡构造系统将斜腿水平推力传递到新增的背墙上,平衡了斜腿根部的水平力。在该桥顶升前,首先进行顶升系统和实时监测设备的安装;然后进行千斤顶安装及充压,拱腿及斜撑切割和试顶升,试顶升后分6级将桥梁整体顶升62 cm;最后连接拱腿和斜撑,拆除临时设施,完成顶升施工。为保证施工安全,在顶升全过程进行桥梁顶升高度、结构应变及顶升姿态实时监测。结果表明:桥梁顶升高度和顶升姿态误差均在允许误差范围内;顶升过程中结构应变变化幅度较小,最大值为102.9με,已通过现场预警控制调整恢复至正常值,结构应力控制在安全范围内。A bridge of the Xiangyang-Jingzhou Expressway that crosses an existing railway is a slant legged rigid frame bridge spanning 52.78 m.To fulfil the clearance requirements,the bridge had to be integrally jacked up 60 cm.Considering the characteristics of the bridge as well as the requirement of uninterrupted traffic,the overall synchronous lifting solution without balanced cable is adopted through scheme comparison.A self-balancing system was installed at the root of the slant leg to transmit the horizontal thrust of the slant leg to the added backwall,aiming to balance the horizontal force at the root of the slant leg.The jack-up system and real-time monitoring devices were adjusted ahead of the jack-up,subsequently,the jacks were installed and pressured,the slant legs and diagonals were cut off.After trial jack-ups,the bridge was integrally raised by 62 cm in six steps.Then the slant legs and diagonals were connected,the temporary facilities were dismantled,the jack-up construction was completed.To ensure construction safety,the jack-up height,structural strain and jacking attitude were monitored in real time during the whole jack-up process.It was shown that the jack-up height and jacking attitudes of the bridge were within the allowable ranges.During the jack-up process,the structural strain exhibited minor changes,with a maximum value of 102.9με,which was adjusted to return to the normal value via the field early warning system,and the structural stresses were controlled within the safe ranges.

关 键 词：斜腿刚构桥 整体顶升 无平衡索 自平衡构造 施工监测 桥梁改造 施工技术 

分 类 号：U448.232[建筑科学—桥梁与隧道工程] U445.4[交通运输工程—道路与铁道工程]