【作者】 赵汗清；

【导师】 施尚伟；

【作者基本信息】 重庆交通大学 ， 结构工程， 2011， 硕士

【摘要】 桥梁结构在行车下的动力响应是桥梁动力学研究的一项重要内容,在运动车辆荷载作用下桥梁结构的变形和应力相比于静载作用下更大。随着我国经济和交通运输事业的迅猛发展,车辆数量、载重量都有了极大的提高,桥梁结构在重载、高速行车作用下的冲击响应问题,越来越受到桥梁研究者的关注。桥梁冲击系数是反映结构动力响应的关键性参数之一,本文围绕试验样本统计分析及数值计算模拟这两个研究方法,在收集了大量试验样本后,对简支及连续梁桥、拱桥进行了冲击系数或应变增大系数统计分析,并利用有限元软件建立模型分析实桥动力特性。利用收集到的大量简支及连续梁桥、拱桥动力试验报告,整理出各桥实测频率、实测冲击系数或应变增大系数及阻尼比资料。由以上实测数据分析结构基频、车速两个因素对实测冲击系数的影响并作了相关分析。利用统计分析软件,比选各种数学模型后建立了最优的梁桥及拱桥实测基频-冲击系数(应变增大系数)关系函数并利用拟合函数取值与工程实测值进行对比,验证其有效性。由同桥实测冲击系数与实测应变增大系数为依据探讨了两系数间关联性。利用有限元软件ANSYS,建立了罗岩大桥车-桥耦合动力模型,计算得到不同车速作用下罗岩大桥理论冲击系数并与实测应变增大系数作对比。改变车辆模型自由振动频率至桥梁二阶竖向振动频率,对比改变前后理论冲击系数大小差异,验证车-桥耦合对冲击效应的放大作用。将有限元计算得出的各工况冲击系数、模态参数同实测值对比分析,评价罗岩大桥结构安全性能。更多还原

【Abstract】 The dynamic response of the bridge structure under in running vehicle is one of the important parts of the bridge dynamics research,the deformation and stress of bridge structure in moving vehicle loads is greater than static load.Along with rapid development of our country’s economy and transportation,vehicles quantity and load has improved tremendously, impact response of bridge in overloaded, high-speed running vehicle has more and more attentions of bridge researchers.Bridge impact coefficient is one of key parameter of the structure dynamic response.This paper focus on two research methods:test sample statistic analysis and numerical simulation, after in a large collection of test sample, do the impact coefficient or strain increases coefficient statistics analysis of simply-supported and continuous girder and arch bridge, and using finite element software to build model to analysis dynamic characteristics.Using collected lots of simply supported and continuous girder bridge,arch bridges dynamic test report,sort out each bridge’s measured frequency,impact coefficient or strain increases coefficient and the damping ratio. By analysising above measured data get the relationship between actual impact coefficient of and speed/ basic frequency . Using the statistical software, after choosing various mathematical model and then established function of the measured the fundamental frequency - impact coefficient of girder and arch bridge, and contrast the value of function and a bridge’s measured values,whose effectiveness is verified.Using finite element software, established Luoyan bridge -vehicle coupling dynamic model, calculated under different speeds,compared theoretical impact coefficient and measured stress increase coefficient.Change the free vibration frequency of vehicle model to bridge second-order vibration frequency,contrast before and after value of theory impact coefficient in order to verify the bridge-vehicle coupling effects on amplifying function. Contrast theoretical impact coefficient, modal parameters of the element calculations with measured value in order to evaluation Luoyan bridge structure safety performance.更多还原