基于移动荷载谱的高速铁路简支梁桥基频限值分析  

Analysis of fundamental frequency limits for high-speed railway simply supported beam bridges based on moving load spectrum

作　　者：李锦华[1] 郭继栅 LI Jinhua;GUO Jishan(School of Civil Engineering and Architecture,East China Jiaotong University,Nanchang 330013,China)

机构地区：[1]华东交通大学土木建筑学院,南昌330013

出　　处：《振动与冲击》2024年第21期222-230,共9页Journal of Vibration and Shock

基　　金：国家自然科学基金项目(11962006);江西省自然科学基金项目(20232BAB204067)。

摘　　要：控制桥梁振动响应是保证高速列车安全稳定运行的关键,遵循梁体不发生共振或较大位移响应的原则,提出了简支梁桥基频限值频域分析法。首先基于移动荷载列模型,通过傅里叶变换得到了桥梁振动响应谱和移动荷载谱,并从时域角度验证了谱的正确性;然后通过引入间跨比γ和无量纲速度κ,探究了在不同移动荷载列作用下桥梁自由振动发生最大位移响应时,无量纲速度κ和间跨比γ之间的关系;其次根据γ-κ关系曲线分析了24 m、32 m、40 m简支梁桥最大位移响应下的无量纲速度κ;最后为了避免列车激励下桥梁发生共振或较大位移响应,参考国际铁路联盟基频限值规范,基于移动荷载谱给出了移动荷载列在不同设计时速下24 m、32 m、40 m简支梁桥基频限值建议值。研究表明:移动荷载幅值谱与时域计算的桥梁自由振动位移幅值响应规律一致;单节车长25 m左右的移动荷载列以共振速度激励桥梁时,24 m、32 m简支梁桥自由振动都能达到最大位移响应,而40 m简支梁桥仅产生较大位移响应,且在列车运营速度范围内达不到产生最大位移的条件;桥梁基频限值随着列车时速的增加而增大,当最大设计时速400 km/h时24 m、32 m、40 m简支梁桥基频建议下限值分别为6.00 Hz、4.94 Hz、5.66 Hz。Controlling vibration response of bridges is the key to ensure safe and stable operation of high-speed trains.Here,following the principle of no resonance or large displacement response of beam body,a frequency domain analysis method for fundamental frequency limits of simply supported beam bridges was proposed.Firstly,based on moving load column model,bridge vibration response spectrum and moving load spectrum were obtained using Fourier transform,and the correctness of spectra was verified from the perspective of time domain.Secondly,by introducing the inter-span ratioγand dimensionless velocityκ,the relation betweenκandγwas explored when the maximum displacement response of bridge free vibration occurred under different moving load columns.Then,according toγ-κrelation curve,the dimensionless velocityκwas analyzed under 24 m,32 m and 40 m long simply supported beam bridges’maximum displacement responses.Finally,to avoid resonances or larger displacement responses of bridges under train excitation,referring to the International Railway Union’s Fundamental Frequency Limit Specification,and based on moving load spectrum,fundamental frequency limit recommended values for 24 m,32 m and 40 m long simple supported beam bridges under different design train speeds were given.The study results showed that the amplitude spectrum of moving load is consistent with bridge free vibration displacement amplitude response law calculated in time domain;when a moving load train with single section length of about 25 m excites a bridge at resonance speed,vibrations of both 24 m and 32 m long simply supported beam bridges can reach maximum displacement responses,while 40 m long simply supported beam bridge only has a larger displacement response and can’t reach the condition to have the maximum displacement within the range of train operating speed;bridge fundamental frequency limit value increases with increase in train speed,when the maximum design train speed is 400 km/h,recommended lower limit values for fundamental

关 键 词：移动荷载谱 高速铁路 简支梁桥 基频限值 共振 

分 类 号：U448.4[建筑科学—桥梁与隧道工程]