大跨度三主桁钢桁拱桥墩旁托架设计及施工关键技术  

Key Design and Construction Techniques for Pier-Side Brackets of Long-Span Three-Main-Truss Steel Truss Arch Bridge

作　　者：赵健 安路明 任延龙 刘银涛 张鹏志 ZHAO Jian;AN Lu-ming;REN Yan-long;LIU Yin-tao;ZHANG Peng-zhi(China Railway Construction Bridge Engineering Bureau Group Co.,Ltd.,Tianjin 300300,China;China Railway Construction Bridge Engineering Bureau Group Co.,Ltd.,Technology Center,Tianjin 300300,China)

机构地区：[1]中国铁建大桥工程局集团有限公司,天津300300 [2]中国铁建大桥局有限公司技术中心,天津300300

出　　处：《世界桥梁》2021年第4期7-12,共6页World Bridges

基　　金：天津市科技开发计划项目(19YDL ZSF00030);中国铁建股份有限公司科技开发项目(2018-C05);中国铁建大桥工程局集团有限公司科技研究开发课题(DQJ-2019-B24)。

摘　　要：广州明珠湾大桥为(96+164+436+164+96+60)m三主桁双层桥面中承式钢桁拱桥。大桥采用“拱梁同步”大悬臂拼装架设,由于主桥施工处于深水区,无法搭设临时墩支撑,因此在顺桥向主墩两侧设置墩旁托架临时支撑主墩钢桁梁初始节间。墩旁托架支撑在既有承台墩身上,由上托架、下托架及上、下托架之间的钢梁姿态调控装置组成。托架设计为稳定的三脚架结构,以克服施工过程中主墩支座两侧由于受力不平衡而产生的倾覆力矩;下托架钢管内填充自密实微膨胀混凝土,并在水平钢管内设置预应力钢绞线,以提高托架整体刚度,抵抗钢梁拼装产生的水平力;调控装置精确调整钢桁梁初始节间纵、横向及高程位置,操作简单、易控。整体结构受力计算结果表明:在最不利工况作用下,墩旁托架受力状态满足施工要求且有足够的安全度。对墩旁托架预埋件、下托架、上托架和钢梁姿态调控装置进行安装,钢梁在拼装完墩顶2个节间后,对钢梁中线和高程进行1次精确调整,确保了钢梁悬臂架设支撑安全及线形满足设计要求。The Mingzhu Bay Bridge in Guangzhou is a half-through steel truss arch bridge that have six spans of 96,164,436,164,96 and 60 m.The bridge contains three main trusses and accommodates two-levels of decks.During construction,the arch and the deck were erected in parallel by a long-cantilever assembly method.Due to that the main bridge is located in the deep water area,temporary piers were not available,and pier-side brackets along the bridge length were installed to temporarily support the starter steel truss segments on the top of main piers.The pier-side brackets were mounted on the existing pile caps and pier columns,which were composed of upper and lower brackets,together with the steel girder position tuning devices in between.The brackets are designed as stable tripod structures that can resist the overturning moment induced by the uneven loading condition at the two sides of the main pier bearings.The lower bracket was filled with self-compacting micro-expansion concrete,in the horizontal steel tubes of which,prestressing tendons were added to improve the integral rigidity of the brackets,and in turn to counteract the horizontal forces generated during the steel girder assembly.The tuning devices facilitated the precise adjustment of the longitudinal and transverse position as well as the elevation of the starter steel truss segments.The calculation of the load bearing performance of the overall structure showed that the pier-side brackets could meet the load bearing requirements and have sufficient levels of redundancy.The embedded elements,upper and lower brackets of the pier-side bracket structure as well as the position tuning devices of the steel girder were installed.Once the two steel girder segments on the pier heads were erected into position,the central line and elevation of the steel girder were accurately adjusted for one time,which ensured the safe support for the steel girder cantilever erection and the required design geometry of the steel girder.

关 键 词：钢桁拱桥 悬臂拼装 墩旁托架 自密实微膨胀混凝土 预应力钢绞线 调控装置 数值模拟 施工技术 

分 类 号：U448.224[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]