长沙中低速磁浮运营线列车-桥梁系统耦合振动试验研究

为探究不同桥梁结构形式对中低速磁浮列车-桥梁系统耦合振动的影响,选取长沙中低速磁浮运营线中的两种典型桥梁:一跨25m简支梁和(25+35+25)m连续梁为研究对象,开展现场动载试验,测试了列车在桥梁上运行时车辆及桥梁的动力响应。首先分析两种桥梁的基频特性并与仿真值进行了对比,随后分析了车辆与桥梁的动力特性及振动加速度频谱分布特征。结果表明:两种桥梁基频的仿真值与实测值较为吻合;在磁浮列车作用下,简支梁及连续梁竖向加速度峰值均集中在20Hz以内,横向加速度峰值分布在20~80Hz,其中简支梁的振动加速度幅值整体大于连续梁。列车通过简支梁时,车体、悬浮侧架的振动频谱峰值分布与通过连续梁时一致,通过简支梁时的振动幅值更大;悬浮侧架竖、横向加速度远大于车体,空气弹簧具有良好的隔振效果。试验研究成果可为磁浮高架桥梁设计、相应规范或标准的制定提供借鉴。

Tests for coupled vibration of a train-bridge system on Changsha low-medium speed maglev line

In order to study effects of different bridge structures on coupled vibration of a low-medium speed maglev train-bridge system, field tests were conducted for a maglev train running on two typical bridges of Changsha low-medium speed maglev commercial operation line including a25 m simply-supported girder bridge and a (25+35+25) m continuous one. Dynamic responses of vehicles and these two bridges were measured. Firstly, fundamental frequency characteristics of these two bridges were analyzed and compared with simulated ones. Then, dynamic characteristics and vibration acceleration spectra of the train and two bridges were analyzed. The results showed that the simulated fundamental frequencies of the two bridges agree well with the measured ones;under the action of the maglev train, the two bridges’ vertical vibration acceleration peaks are concentrated in the frequency range of 0-20 Hz, while their lateral vibration acceleration peaks are distributed in the frequency range of20-80 Hz;vibration acceleration amplitudes of the simply-supported girder bridge are totally larger than those of the continuous one;vibration spectral peak distributions of car bodies and suspension side frames when the train passing through the simply-supported bridge coincide with those when the train passing through the continuous one, vibration amplitudes when the train passing through the former are larger than those when it passing through the latter;vertical and lateral vibration accelerations of suspension side frames are much larger than those of car bodies, so air springs have good vibration isolation effect;the results can provide a reference for designing magnetic suspension viaducts and formulating corresponding norms and standards.