桥梁节段与实桥涡激共振幅值的换算关系  

Similarity of amplitude of sectional model to that of full bridge in the case of vortex-induced resonance

作　　者：张志田[1] 陈政清[1] 

机构地区：[1]湖南大学风工程试验研究中心,湖南长沙410082

出　　处：《土木工程学报》2011年第7期77-82,共6页China Civil Engineering Journal

基　　金：国家自然科学基金项目资助(90915002;50708036;50738002)

摘　　要：涡激共振是大跨桥梁最易出现的一种风振现象,其研究手段以节段模型风洞试验为主。节段模型涡振振幅与实桥涡振振幅如何转换,目前我国《公路桥梁抗风设计规范》缺少相关说明。本文首先介绍了桥梁涡激共振时三种涡振力理论模型的特点,包括线性模型、非线性模型以及修正的非线性模型。根据输入能量相等则振幅相等的原理推导了主梁等效质量与涡振振型函数的关系。在此基础上,提出了不同涡振力理论模型下节段模型涡振振幅与实桥最大涡振振幅的换算关系。研究表明,影响该换算关系的主要因素有两方面,一是主梁发生涡振时的振型,二是所采用的涡振力理论模型。采用日本规范值或有关文献根据线性模型所得的换算关系所计算的实桥最大振幅将明显大于基于非线性涡振力模型推算的实桥最大振幅。Vortex-induced resonance is caused by wind to which long-span bridges are most susceptible.One method of study is to use section model test in wind tunnel.How can the vortex-induced amplitude of sectional model be converted to that of the full bridge is an unresolved issue in the present Chinese wind-resistant design specifications of highway bridges.The present paper introduces three kinds of theoretical models for vortex-induced aerodynamic forces,including the linear model,the nonlinear model,and the modified nonlinear model.The relation between the equivalent mass density of girder and the modal function is deduced according to the principle that equal energy input should result in equal amplitude.Based on these,a group of conversions between amplitude of sectional model and that of full bridge,corresponding to different theoretical models,are presented.The study indicates that there are two major factors to influence the conversion relationship,with one being the structural modal shape,and the other the theoretical model adopted in the expression of vortex-induced loading.Based on the amplitude of sectional model,the amplitude of full bridge from using the linear model is obviously larger than that from the nonlinear one.

关 键 词：涡激共振 节段模型 全桥 振幅换算 

分 类 号：U448.14[建筑科学—桥梁与隧道工程]