多跨预应力混凝土连续梁整体平移改造施工关键技术  

Overall Translation Techniques of Multi-Span Prestressed Concrete Continuous Girders

作　　者：代保平[1] 戴军翔 DAI Baoping;DAI Junxiang(China Railway Major Bridge Engineering Group Co.,Ltd.,Wuhan 430050,China)

机构地区：[1]中铁大桥局集团有限公司,湖北武汉430050

出　　处：《世界桥梁》2024年第2期114-119,共6页World Bridges

摘　　要：宿迁古黄河老桥为(22.5+3×30+22.5)m四幅分离式连续梁桥,两侧为非机动车道桥,中间为机动车道桥。由于该桥位于生态保护区且梁体质量良好,为满足迎宾大道二期快速化改造需要,采取在不中断交通的前提下,通过交通导改先后将西侧和东侧机动车道桥分别往两侧整体平移3.25 m,再于中间修建新桥的改造方案。结合桥位处水文地质情况,采用在非机动车道桥外侧设置“钢板桩+过水钢管”围堰进行无水条件下的基础墩身拼宽施工。改造施工时,根据单侧机动车道桥支座处顶升荷载及梁底空间选配布置顶升千斤顶和步履器;通过有限元计算确定梁体顶升与平移施工过程中各支点竖向和横向位移偏差控制指标,采用PLC液压同步控制系统操控步履器与千斤顶交替顶升与平移,既能保证梁体整体顶升与平移的精度又能有效控制梁体应力突变;待梁体平移到设计位置后,拆除步履器和顶升千斤顶,复原垫石、支座及挡块。The bridge crossing the abandoned Yellow River channel in Suqian is a continuous girder bridge with spans of 22.2 m,3×30 m,and 22.5 m.The superstructure consists of four separated decks,where the outer two decks carry pedestrians and cyclists,and the central two decks accommodate vehicles.Located in an ecological reserve,the bridge has sound girders after decades of service.To meet the requirements of rapid reconstruction of the Yingbin Avenue without traffic closure,each of the original vehicle deck was integrally translated 3.25 m outwards after traffic diversion,leaving space for the planned viaduct.Considering the hydraulic conditions,a cofferdam consisting of steel sheet piles and water-flowing steel tubes was built outside each pedestrians/cyclists deck to assist the widening of piers in dry environment.During reconstruction,the jacks and pedometers were selected and distributed in accordance with the jack-up loads at the bearings underneath each vehicle deck and the space below girder soffit.Numerical calculation was carried out to determine the control indexes of vertical and transverse displacement deviations at supports during the jack-up and translation of girders.A PLC hydraulic synchronous control system was employed to control the alternate working of the pedometers and jacks,to ensure the accuracy of integral jack-up and translation of the deck and control the abrupt stress change.Once the deck was translated into the design position,the pedometers and jacks were demolished,and the pad stones,bearings and stoppers were moved to the original locations.

关 键 词：混凝土连续梁桥 旧桥改造 步履式 同步顶升 整体平移 施工技术 

分 类 号：U448.215[建筑科学—桥梁与隧道工程] U445.7[交通运输工程—道路与铁道工程]