基于主梁受力特点的部分斜拉桥合理成桥状态确定方法研究  

Research on Methods to Determine Rational Completion State for Extradosed Bridge Based on Load Bearing Characteristics of Main Girder

作　　者：张家元 吴学伟 张铭 ZHANG Jia-yuan;WU Xue-wei;ZHANG Ming(Hubei Provincial Communications Planning and Design Institute Co.,Ltd.,Wuhan 430051,China;Hubei Provincial Communications Investment Group Co.,Ltd.,Wuhan 430050,China)

机构地区：[1]湖北省交通规划设计院股份有限公司,湖北武汉430051 [2]湖北省交通投资集团有限公司,湖北武汉430050

出　　处：《世界桥梁》2021年第4期35-41,共7页World Bridges

基　　金：湖北省交通运输厅科技项目(2020-186-1-1)。

摘　　要：为确定部分斜拉桥合理成桥状态,以斜拉桥主梁竖向受力特征为基础,对部分斜拉桥主梁竖向受力特点、典型特征参数进行分析,据此提出部分斜拉桥的合理成桥状态目标为主梁体外预应力和体内预应力的最优配置,并以武汉三官汉江大桥为背景进行实例分析。结果表明:常规斜拉桥主梁是传递桥面活载、平衡斜拉索水平分力的加劲梁,索力恒载比γ_(c)为0.75~0.92;部分斜拉桥主梁受力以受弯为主,索力恒载比γ_(c)为0.34~0.43,部分斜拉桥斜拉索可视为主梁的体外预应力;借助索力恒载比γ_(c),以体外、体内预应力作用和恒载作用下主梁竖向弯矩相平衡为原则,快速确定了武汉三官汉江大桥合理成桥状态(γ_(c)=0.36),改变γ_(c)对该桥斜拉索竖向荷载分担率β基本没有影响,该桥墩顶区索力的弯矩等效偏心距最大值是体内预应力的12.65倍,斜拉索作为体外预应力平衡墩顶负弯矩的效率高。The vertical load bearing behavior of the main girder of extradosed bridge and typical characteristic parameters were analyzed based on the analysis of the conventional cable-stayed bridge,aiming to determine the rational completion state of the extradosed bridge.It is recommended that the rational target completion state of the extradosed bridge be used to determine the optimal composition of external and internal prestressing tendons in the main girder.The Sanguan Hanjiang River Bridge in Wuhan is used as a case for the study.For the conventional cable-stayed bridge,the main girder acts as a stiffening girder that transfers live loads and balance horizontal component of stay cables,with the ratio of cable force and dead loadγ_(c) ranging from 0.75 to 0.92.Nevertheless,the extradosed bridge is mainly subjected to bending force,with a ratio of cable force and dead loadγ_(c) ranging between 0.34 and 0.43.The stay cables of an extradosed bridge can be regarded as the external prestressing tendons of the main girder.Counting on the ratio of cable force and dead loadγ_(c) and maintaining the balance between the main girder vertical bending moments under the actions of internal and external prestressing as well as dead loads,respectively,the rational completion state of the Sanguan Hanjiang River Bridge in Wuhan was rapidly determined,γ_(c) was 0.36,and the variation ofγ_(c) exerted negligible effect on the vertical load sharing ratioβof the stay cables.The maximum equivalent eccentricity of bending moment of the pier-top cable forces is about 12.65 times of the internal prestressing.For the extradosed bridge,stay cables can act as external prestressing tendons that are effective in balancing the pier-top hogging moment.

关 键 词：部分斜拉桥 斜拉桥 合理成桥状态 索力恒载比 体外预应力 等效偏心距 桥梁设计 

分 类 号：U448.27[建筑科学—桥梁与隧道工程] U441[交通运输工程—道路与铁道工程]