曲线形独塔无背索斜拉桥施工控制关键技术

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桥梁建设2018年第48卷第2期（总第249期）Bridge Construction, Vol. 48, No. 2, 2018 (Totally No. 249)

文章编号：1003 —4722(2018)02 —0116 —05

曲线形独塔无背索斜拉桥施工控制关键技术

易云棍

(厦门理工学院，福建厦门361000)

摘要：漳州市双鱼岛内环北路桥为跨径（110 +25) m的曲线形独塔无背索斜拉桥，采用塔 梁墩固结体系，主梁采用钢一混凝土混合梁结构。该桥采用先梁后塔、塔索同步的总体施工方案，为保证成桥后的内力和线形满足设计要求，采用无应力状态控制法对该桥进行施工控制。在该桥 施工控制中，通过设置预换度控制主梁线形；通过设置纵向预偏量和预抛高控制桥塔线形；采用割 线法进行索导管倾角修正；通过张拉索力和2次放索控制桥塔内力，斜拉索一次张拉到位；采用“减小张拉索力+调整螺母位置”的方法解决斜拉索的“超长”问题；通过2次放索将张拉索力调整到成 桥索力，采用迭代法计算放索之前的目标索力。内环北路桥已建成，成桥后的桥梁线形和内力均符 合设计要求。

关键词：独塔斜拉桥；无背索桥塔；混合梁；无应力状态控制法；线形；索导管倾角；内力；施工控制

中图分类号：U448.27;U445.4 文献标志码：A

Key Techniques for Construction Control of a Curved

Single Pylon Cable-Stayed Bridge Without Backstays

YI Yun-kun

(Xiamen University of Technology, Xiamen 361000, China)

Abstract：The Neihuan North Road Bridge in Shuangyu Island, Zhangzhou City is a curved single pylon cable-stayed bridge without backstays with spans of (110 + 25) m. The structural sys­tem of the bridge is the rigid fixity system of the pylon, main girder and pier and the main girder is the structure of the steel and concrete hybrid girder. The bridge was constructed, using the scheme of constructing the main girder before constructing the pylon and constructing synchro­nously the pylon and stay cables. To ensure that the internal forces and geometric shapes of the completed bridge could meet the design requirements, the construction control of the bridge was carried out, using the unstressed state control method. In the construction control, the geometric shape of the main girder was controlled, using the set pre-cambering and the geometric shape of the pylon was controlled, using the set longitudinal offsetting amount and initializing height. The dip angles of the stay cable ducts were corrected, using the secant method and the internal forces of the pylon were controlled, using the tensioned cable forces and by way of relaxing the cables for 2 times. The stay cables were substantially tensioned in place in one time and the problem of the "excessive length" of the cables was resolved, using the method of "reducing the tensioned cable forces +adjusting the nut positions". By relaxing the cables for the 2times, the tensioned cable forces were adjusted to the cable forces of the completed bridge and the target cable forces before

收稿日期：2017 — 04 —19

基金项目：国家重点研发计划项目（2017YFC0806009)

Project of National Key Research and Development Program (2017YFC0806009)

作者筒介：易云焜，副教授，E-m ail:26294786〇®q q. c o m…研究方向：大跨度桥梁结构体系，桥梁建设管理…

曲线形独塔无背索斜拉桥施工控制关键技术 易云焜117

the cables were relaxed were calculated, using the iteration method. Presently, the Neihuan North Road Bridge has been completed and the internal forces and geometric shapes of the completed bridge can all meet the design requirements.

Key words：single pylon cable-stayed bridge；pylon without backstays；hybrid girder；un­stressed state control method；geometric shape；dip angle of stay cable duct；internal force；con­struction control

1概述

漳州市双鱼岛内环北路桥位于招商局漳州开发 区双鱼岛，为无背索独塔斜拉桥，采用塔梁墩固结的 刚构体系，跨径布置为110 m +25 m，如图1所示。主梁采用钢一混凝土混合梁结构，其中，钢箱梁长 91 m，预应力混凝土箱梁长44 m，钢一混结合段长 2m，钢箱梁与预应力混凝土箱梁分界点位于主跨 侧距离塔梁固结点19 m处。预应力混凝土箱梁和 钢箱梁均采用单箱三室结构，其高度分别为3m和2 m。桥塔采用钢筋混凝土结构，横向布置于中央 分隔带。桥塔高72.0 m(承台以上），纵向因景观造 型需要采用样条曲线进行拟合，桥塔中段的倾斜角 约50°，塔底、塔顶角度接近垂直[1]。桥塔采用倒角 矩形截面，横桥向为3m等宽截面，顺桥向横断面 宽从塔底的11. 75 m变化到塔顶的3. 25 m。采用 平行钢丝斜拉索，双索面之间的间距为1.8m，塔端 张拉。

内环北路桥采用先梁后塔、塔索同步的总体施 工方案。在综合分析该桥原施工工序(设计提供）的基础上，将内环北路桥施工工序优化为：①搭设支架，现浇预应力混凝土箱梁、钢一混结合段，在支架上安装钢箱梁；②张拉预应力混凝土箱梁的预应力；③浇筑钢箱梁上的钢纤维混凝土；④搭设桥塔 施工平台，通过劲性骨架逐段悬臂浇筑桥塔节段，塔 端同步张拉相应的斜拉索;⑤放索，拆除主梁支架;

⑥放索，拆除桥塔支架；⑦完成剩余桥面系及附属 工程施工；⑧成桥。

内环北路桥结构新颖，施工工序众多、工艺复 杂。因此，必须对该桥进行全过程控制。为保证施 工过程中结构始终处于安全范围内、成桥后的线形 和内力状态均满足设计和规范要求，该桥采用无应 力状态控制法进行施工控制[2]。内环北路桥施工控 制以桥塔和主梁的受力和线形、斜拉索索力等与设 计基本一致为目标。针对该桥施工监控，本文主要 介绍主梁和桥塔线形控制、索导管倾角控制、桥塔内 力控制等关键施工控制技术。

2施工控制关键技术

2.1主梁线形控制

该桥主梁预应力混凝土箱梁段采用支架现浇法 施工，钢箱梁段采用分段拼装施工（钢箱梁分为11 个节段，标准段长8 m

)。主梁线形主要通过设置主