摘要
某城市景观桥为(22+55+22) m空间斜靠式三跨拱梁组合桥,与河道斜交布置,结构造型新颖。钢梁立面位于凸曲线上,上游侧和下游侧主、副拱在平面上呈反对称结构,上、下游吊杆索力不对称,施工线形控制难度大,制造及安装精度要求高。采用“先梁后拱”施工方法,基于无应力状态法,建立有限元分析模型,确定钢梁和主、副拱及吊杆的无应力状态量,工厂制造严格按照监控指令线形进行。钢梁总体线形通过支架顶标高进行调节,确保钢梁处于无应力线形状态。钢梁节段之间通过匹配件进行锁定定位,确保节段拼装线形与无应力线形匹配。空间结构的主拱安装线形通过支架柱顶的调节装置进行调节,确保安装线形满足要求。全桥的焊接量较大,通过焊接工艺评定,不同的构件采用合适的焊接工艺和施焊顺序,严格控制钢梁的焊接变形。成桥实测线形和索力均满足设计和规范要求。
An existing urban landscape bridge is an arch and continuous girder composite structure with a main span of 55 m and two side spans of 22 m and crosses the river with a skew angle.The bridge features its spatial outwardly-inclined arches.In elevation view,the superstructure alignment exhibits a convex curve,the main and secondary arches both upstream and downstream are asymmetrically laid out on plan,and the forces of the upstream and downstream hangers are uneven,as a result,it is quite challenging to control the alignment of the bridge during construction.Additionally,the manufacturing and installation accuracy is critical.The continuous girder was constructed prior to the arches.Considering the stress-free state method,a finite element model was developed to analyze the stress-free conditions of the steel girders,main and secondary arches and hangers.The components were manufactured in the factory strictly following the commanded alignment.The overall alignment of the steel girders was tuned via the top elevation of the scaffolds to ensure that the steel girders be in the stress-free state.The steel girder segments were locked for positioning via fit-ups to make sure that the assembly alignment commensurate with the stress-free alignment.The installation alignments of the spatial arches were adjusted via the devices installed on the top of the scaffolds for the required level.The welding work of the bridge is colossal,by the welding procedure assessment,appropriate welding procedure and sequence is selected for different components,aiming to bring the welding deformation of the steel girder under stringent control.The measured alignment and stay cable forces of the completed bridge meet the design and code requirements.
作者
朱勤
ZHU Qin(Shenzhen Municipal Design&Research Institute Co.,Ltd.,Shenzhen 518035,China)
出处
《世界桥梁》
北大核心
2022年第6期35-42,共8页
World Bridges
关键词
拱梁组合桥
斜靠式
空间异形结构
先梁后拱
无应力状态法
线形
施工控制
arch and continuous girder composite bridge
outward inclination
spatial irregular structure
girder erection prior to arch
stress-free state method
alignment
construction control
