基于膜结构假定的无背索斜拉桥主梁轴力解析  

Analysis of Axial Force of Main Girder of No Backstays Cable Stayed BridgeBased on Membrane Structure Assumption

作　　者：黄晨光 林丽霞[1] 丁南宏[1] HUANG Chen-guang;LIN Li-xia;DING Nan-hong(School of Civil Engineering,Lanzhou Jiaotong University,Lanzhou 730070,China)

机构地区：[1]兰州交通大学土木工程学院,甘肃兰州730070

出　　处：《兰州工业学院学报》2021年第3期1-5,共5页Journal of Lanzhou Institute of Technology

基　　金：国家自然科学基金(51268028)。

摘　　要：为探索密索体系无背索斜拉桥主梁轴力的非线性特征,寻找快速计算主梁轴力的近似方法,基于平衡荷载理论及膜结构假定,考虑斜塔倾角及主梁无索区长度影响,建立索面以扇形式、竖琴式及辐射式布索时的主梁轴力解析式.结果表明:3种布索方式中,辐射式布索时主梁轴力非线性最为明显,竖琴式布索时主梁轴力最大;适当减小恒活载、增大高跨比均可以减小主梁轴力,缓解近塔处截面的轴力负担.计算结果与有限元法结果吻合良好,误差在5%左右,且整体有包络趋势,是一种偏于安全的计算方法.In order to explore the nonlinear characteristics of the axial force of the main girder of the no backstays cable-stayed bridge with dense cable system and to find an approximate method to quickly calculate the axial force of the main girder,based on the balanced load theory and membrane structure assumption,considering the influence of the inclined tower angle and the length of the cable free zone of the main girder,the analytical for-mula of the axial force of the main girder is established when the cable plane is arranged in the form of fan,harp and radiation.The results show that:among the three kinds of cable arrangement,the radial cable arrangement has the most obvious nonlinear axial force,and the harp cable arrangement has the largest axial force.Reducing the dead live load and increasing the height span ratio can reduce the axial force of the main girder and relieve the axial load of the section near the tower.In addition,the calculation results of this formula are in good agree-ment with those of the finite element method,the error is about 5%,and there is a enveloping trend,so it is a safe calculation method.

关 键 词：无背索斜拉桥 膜结构假定 主梁轴力 轴心抗压 

分 类 号：U448.27[建筑科学—桥梁与隧道工程]