摘要
斜拉桥索塔锚固区是索塔主要受力部位.为提高锚固区的水平承载能力并且满足抗裂性要求,通常在混凝土索塔锚固区设U形环向预应力,在受拉区储存压应力从而改善结构受力,因此环向预应力施工质量对整个斜拉桥安全可靠性至关重要.锚固区预应力体系主要有钢绞线、高强钢丝两种,由于环向高强钢丝施工时普遍存在张拉工艺不稳定、经常产生断丝超标等现象,严重影响预应力张拉质量,因此目前在国内应用较少.本文依托广西贵港市青云大桥预应力高强钢丝施工实践,通过实测现场U形预应力孔道形状、计算机模拟孔内钢丝位置以及自行研制一种镦头锚体系预应力张拉装置的措施,大幅降低断丝率,提高张拉作业的安全性,为类似工程施工提供参考.
The cable tower anchorage zone of cable-stayed bridge is the main forced part of cable tower.In order to raise the horizontal bearing capacity of anchorage zone and meet the requirements of crack resistance,U-shaped circumferential prestressed force is usually set in the anchorage zone of concrete cable tower to store compressive stress in the tension zone so as to improve the structural stress.Therefore,the construction quality of circular prestressed force is very important for the safety and reliability of the whole cable-stayed bridge.There are two kinds of prestressed systems in anchorage area,including steel strand and high strength steel wire.Due to the instability of tensioning process and frequent breakage of wire in excess of standard in the construction of circumferential high strength steel wire,it will seriously affect the quality of prestressed tensioning.In this paper,based on the prestressed high strength steel wire construction practice of Qingyun Bridge in Guigang City of Guangxi,the proportion of broken wires was greatly decreased,and the security of tensioning operation was improved by the field U-shaped prestressed hole shape,computer simulation of hole wire position and developing a upsetting-anchor system of prestressed tensioning device.It could provide a reference for similar engineering construction.
作者
唐文喜
Tang Wenxi(China Railway 17^th Bureau Group 4^th Engineering Co.Ltd.,Chongqing 401121,China)
出处
《铁道建筑技术》
2019年第11期66-69,共4页
Railway Construction Technology
基金
中国铁建股份有限公司科技研究开发计划项目(14-C21)
关键词
小半径
环向预应力
高强钢丝
镦头锚
技术
small radius
circumferential prestress
high strength steel wire
upsetting-anchor
technology
作者简介
唐文喜(1975-),男,湖南怀化人,高级工程师,主要从事隧道与桥梁工程科研方面的工作,E-mail:497816523@qq.com。
