基于索梁组合结构的悬索桥锚跨段索力修正算法  

A Correction Algorithm of Cable Force in Anchorage Span of Suspension Bridge Based on Cable-stayed Beam Structure

作　　者：范剑锋[1] 刘涛[1] 彭自强[1] 刘争 FAN Jian-feng;LIU Tao;PENG Zi-qiang;LIU Zheng(School of Civil Engineering and Architecture,Wuhan University of Technology,Wuhan Hubei 430070,China)

机构地区：[1]武汉理工大学土木工程与建筑学院,湖北武汉430070

出　　处：《公路交通科技》2019年第4期66-71,共6页Journal of Highway and Transportation Research and Development

摘　　要：在悬索桥锚跨段索力测试中,传统的振弦法将锚跨段索振动看作为理想弦振动,忽略了锚跨段拉杆的抗弯刚度,带来了较大的索力测量计算结果误差。为了求解更加精确的锚跨段索力值,保证悬索桥主缆索力监控的精确性、成桥阶段主缆线型的准确性和吊索索力的均匀分布,通过分析索梁组合结构模型,建立了锚跨拉杆与锚跨主缆的索梁组合力学模型,运用主缆振动频率的索力计算方法,运用Hamilton变分原理推导提出悬索桥锚跨段,锚跨拉杆与锚跨主缆的索梁组合结构的索力修正算法。分析了锚跨拉杆与索连接处的边界条件问题,保持索梁连接处为铰接状态,不改变边界条件的物理属性。基于Mathematica数学计算软件上,设计求解程序并求解索梁组合结构振动矩阵方程,得出对应索梁组合结构频率的索力值的数值解。通过对比分析数据理论计算、有限元分析软件及恩施水布垭清江特大悬索桥实际工程实例测量结果,来验证考虑悬索桥锚跨段拉杆的抗弯刚度修正算法的合理性。研究结果表明:相对于传统的索力测试简化算法,运用索梁组合结构推导的锚跨段索力计算公式,可以更准确地表达索力、锚跨拉杆抗弯刚度和索力基频之间的关系,进而减小因为拉杆抗弯刚度所带来的索力计算结果的误差,得到更加符合实际主缆张拉状态的索力值。Traditional vibrating string method omits the influence of flexural rigidity of anchorage span tie in suspension bridge while measuring the cable force in anchorage span of suspension bridge,resulting in great deviation of the cable force measurement and calculation.In order to solve more accurate cable force of anchorage span section and guarantee accurate monitoring on main cable,the accuracy of main cable’s geometric shape in completion stage and the uniform distribution of hoist cable force,by analyzing the cable-stayed beam structure,the mechanical model of the cable-stayed beam structure which consists of tie and main cable of anchorage span is established.The main cable force is calculated by utilizing the calculation method based on main cable frequency.The correction algorithm of the cable force in the abovementioned anchorage span and cable-stayed beam structure is derived by using Hamilton’s variational principle.The boundary condition for the joint of anchor rod and cable is analyzed to keep the hinge state of the joint and the physical property of the boundary condition.Based on the Mathematica software,the program is designed to solve the vibration matrix equation of the cable-stayed beam structure,and the numerical solution of the cable force corresponding to the vibration frequency of the cable-stayed beam structure is obtained.By contrasting the numerical calculation with FE analysis result and real measurement of a grand suspension bridge,the rationality of the correction algorithm considering the flexural rigidity of the anchor tie of the cable-stayed bridge is verified.The research result indicates that(1)using the calculation formula of cable force of anchorage span derived by cable-stayed beam structure can more accurately describe the relationship among cable force,flexural rigidity of anchor tie and fundamental frequency of cable force compared with traditional simplified cable force calculation method;(2)it can also reduce the calculation deviation caused by flexural rigidity of ancho

关 键 词：桥梁工程 锚跨索力 Hamilton变分原理 索梁组合结构 修正算法 弦振动 有限元数值模拟 

分 类 号：U443.4[建筑科学—桥梁与隧道工程]