大跨径整孔预制箱梁张拉方式及反拱度设置研究  

Methods to Tension Prestressed Tendons and Set Inverted Camber for Long-Span Prefabricated Box Girder

作　　者：王文洋 王通 王毓晋 WANG Wen-yang;WANG Tong;WANG Yu-jin(China Railway Bridge Science Research Institute,Ltd.,Wuhan 430034,China;State KeyLaboratory for Health and Safety of Bridge Structures,Wuhan 430034,China;ZhejiangZhoushan Northward Channel Co.,Ltd.,Zhoushan 316000,China)

机构地区：[1]中铁大桥科学研究院有限公司,湖北武汉430034 [2]桥梁结构健康与安全国家重点实验室,湖北武汉430034 [3]浙江舟山北向大通道有限公司,浙江舟山316000

出　　处：《桥梁建设》2019年第A01期74-79,共6页Bridge Construction

摘　　要：为改善大跨径预制箱梁桥的成桥线形,以宁波舟山港主通道公路工程跨海桥梁70m箱梁为背景,采用MIDASCivil软件建立5×70m箱梁桥有限元模型,分析不同预应力张拉方式下的箱梁挠度,选择有利于线形控制的预应力张拉方式;对比箱梁预应力长期反拱值与荷载短期效应组合下的长期挠度,确定预拱度的方向及取值比例。结果表明:70m预制箱梁预应力分次张拉边、中跨跨中累积位移比分批张拉分别大19.5mm和18.9mm,预应力分批张拉更有利于整体线形的控制;大跨径整孔预制箱梁按跨中累积挠度的60%来设置反拱度,可以较好地实现线形控制目标。In order to improve the alignment of a long-span prefabircated box girder bridge in the completed bridge state,the 70 m-long span of prefabricated box girder of the sea-crossing bridge in the Ningbo-Zhoushan Port Trunk Highway Project is cited as an example.The software MIDAS Civil was employed to establish the finite element model of the 5×70 m box girder bridge,to analyze the deflection of the box girder when different methods were used to tension the prestressing tendons,and the one that was favorable to the alignment control was selected.Based on the comparison of the long-term inverted camber of the prestressing tendons and the long-term deflection of the box girder under the short-term loading effect,the direction of the precamber and the proportion of the value were determined.The results show that when the prestressing tendons in the 70 m-long spans are tensioned by multiple times,the accumulative displacements in the midspan of the side and central spans are respectively 19.5 mm and 18.9 mm bigger than those got from tensioning by multiple groups,and tensioning by multiple groups is more favorable for the control of the overall alignment.To set the inverted camber against 60% of the accumulative deflection in the midspan of the long-span prefabricated box girder is better to realize the target of alighment control.

关 键 词：箱梁桥 预制 预应力张拉 预拱度 线形控制 挠度 有限元法 

分 类 号：U448.213[建筑科学—桥梁与隧道工程] U445.471[交通运输工程—道路与铁道工程]