铁路桥上直立式声屏障车致振动研究

Vehicle-induced vibration of vertical noise barrier on railway bridge

为研究列车通过时桥上直立式声屏障的振动特性,以某铁路桥上直立式声屏障为工程背景,现场测试了桥梁跨中断面处钢轨、箱梁和声屏障立柱的振动,并对试验结果进行时域分析和1/3倍频程分析。基于车-线-桥耦合振动理论,建立了桥梁-声屏障耦合振动分析模型,通过实测结果验证了模型的可靠性。并进一步探讨了声屏障振动的分布规律以及行车速度对其的影响,并提出了一种减振措施。结果表明:钢轨与箱梁顶板振动均呈现出明显的周期性,峰值频率分别为1250 Hz和200 Hz;声屏障立柱振动要强于箱梁顶板,其中部振动与箱梁顶板具有相似的时程特性,其优势频段为50500 Hz,峰值频率为50 Hz;立柱的振动从梁端向跨中逐渐增大,同一断面内,顶部最为剧烈、底部次之、中部最小,且中部受断面位置影响最为明显;列车时速在120180 km/h时,箱梁和立柱的振动随车速的变化均较平缓,而在180200 km/h时,立柱较箱梁对车速更为敏感;增设翼缘斜撑可有效降低声屏障立柱振动。

In order to study vibration characteristics of vertical noise barrier on railway bridge during trains passing through,a vertical noise barrier on a certain railway bridge was taken as the background.Vibrations of rail,box girder and noise barrier column at mid-span of the bridge were measured on site,and time domain analysis and 1/3 octave analysis were performed on the test data.Based on the vehicle-line-bridge coupled vibration theory,the bridge-noise barrier coupled vibration analysis model was established,and its reliability was verified with the actually measured results.Furthermore,the distribution law of noise barrier vibration and effects of train speed on it were studied,and a vibration reduction measure was proposed.The results showed that vibrations of rail and box girder top plate reveal obvious periodicity,and their peak value frequencies are 1250 Hz and 200 Hz,respectively;vibration of noise barrier column is stronger than that of box girder top plate,and vibration at middle of the former has similar time history characteristics to those of the latter,and the former’s dominant frequency range is 50-500 Hz,and its peak value frequency is 50 Hz;vibration of column gradually increases from bridge end to mid-span,and in the same section,vibration at top of column is the strongest,vibration at mid-column is the smallest and affected by the position of section the most obviously;vibrations of box girder and column vary gently with train speed in the range of 120-180 km/h;during train speed being within the range of 180-200 km/h,column is more sensitive to train speed comparing with box girder;vibration of noise barrier column can be effectively reduced by adding flange braces.