中等跨度轨道交通桥梁有载频率研究

Analysis of Loaded Frequency of Medium Span Rail Transit Bridge

基于实际工程案例分析中等跨度的跨座式单轨与公路、铁路、地铁桥梁的质量和桥上运营车辆的质量,确定了不同类型交通桥梁的车桥质量比。为计算研究车桥质量比对桥梁有载频率变化的影响,根据桥梁固有频率的定义求解桥梁振动微分方程,给出桥梁在列车移动荷载作用下桥梁有载频率的变化。研究表明:跨座式单轨列车车桥质量比远大于同等跨度其他交通类型桥梁,且列车质量大于桥梁质量;有载频率随时间变化,列车过桥中,桥梁有载频率在最小值上下波动;桥梁有载频率与车桥质量比有关,车桥质量比越大,桥梁有载频率变化越明显;频率阶数对桥梁有载频率减小变化率影响较小,随着频率阶数增大,桥梁有载频率的变化过程越剧烈。

Based on actual engineering cases,the quality of medium-span straddle monorail and highway,railway,and subway bridges is analyzed,and the quality of vehicles operating on the bridge,the vehiclebridge mass ratio of different types of traffic bridges is determined.In order to calculate and study the influence of vehicle-bridge mass ratio on the change of the loaded frequency of the bridge,the bridge vibration differential equation is solved according to the definition of the natural frequency of the bridge,and the change of the bridge loaded frequency under the action of the moving train load is given.Research shows that:the loaded frequency changes with time.During the train passing the bridge,the bridge loaded frequency fluctuates near the minimum value;the bridge loaded frequency is related to the vehicle-bridge mass ratio.The larger the vehicle-bridge mass ratio,the more the bridge loaded frequency changes obvious;The frequency order has little effect on the rate of change of the bridge loaded frequency.As the frequency order increases,the bridge loaded frequency changes more drastically.