Investigation on generation mechanism of impact sound radiated from part of shoes of highway bridge and estimation of effectiveness of countermeasures for low-frequency sound

公路桥梁部分蹄部辐射冲击声产生机理研究及低频声对策效果评估

• 批准号: 17560422
• 负责人: SUGIYAMA Toshiyuki
• 金额: $ 2.43万
• 依托单位: University of Yamanashi
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2005
• 资助国家: 日本
• 起止时间: 2005 至 2006
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-17560422/
• 关键词: low-frequency noise; highway bridge; bridge vibration; expansion joint; shoe; TMD

Based on the field measured data corrected in the middle of September, 2005, the relation between displacement of expansion joint (or shoe) and characteristics of vehicle passing over bridge (type of vehicle, velocity, etc.) has been analyzed. However, any significant relation has not been recognized. This may be depend on the fact that the weight of vehicle could not be obtained accurately and the consecutive vehicles must cause the complicated vibration. Then the modeling on behavior of expansion joint and shoe has not been successful at present.On the other hand, the effectiveness of tuned mass damper as countermeasure for low-frequency sound radiated from steel highway bridge has been investigated based on numerical analysis. The three span continuous multi main steel girder highway bridge whose bridge length and width are about 63 meters and 23 meters, respectively is selected as the subject of study. This bridge is currently under service. The bridge is modeled based by using 3-d … More imensional finite element method so as to obtain a good agreement of natural frequencies between field measured values and analytically calculated ones. Totally twelve pieces of tuned mass dampers are equipped with the superstructure of this bridge. In the numerical analysis, a vehicle model with two axles and four degrees of freedom is adopted. And three traveling patterns, that is, one vehicle, two parallel vehicles, and two successive vehicles passing over bridge are considered in this study. Finite element analysis method where numerical integral is executed based on Newmark's 8 method is applied. Sound pressure level is calculated by summing up the sound pressure radiated from the surface of each finite element of bridge deck. An interference phenomenon of sound can be considered in this calculation procedure. Sound receiving position is the point where a horizontal distance perpendicular to the bridge axis is 31 meters and a vertical one downward away from the center of bridge span is 13 meters.The results show that equipment of tuned mass dampers with superstructure leads to 3-4 decibels reduction of low-frequency sound radiated from steel highway bridge against first-order vibration mode. It has been also revealed that about 7 decibels reduction is expected against second-order vibration mode. Less

根据2005年9月中旬修正的现场实测数据，分析了伸缩缝（或鞋）的位移与过桥车辆特性（车辆类型、速度等）之间的关系。然而，尚未发现任何重大关系。这可能是由于车辆的重量无法准确获得，并且连续的车辆必然引起复杂的振动。另一方面，基于数值分析研究了调谐质量阻尼器作为公路钢桥低频辐射对策的有效性。选择桥长约63米、桥宽约23米的三跨连续多主钢梁公路桥作为研究对象。这座桥目前正在使用中。该桥采用三维有限元方法进行建模，以便现场测量值与解析计算值之间的固有频率具有良好的一致性。该桥上部结构共有十二块调谐质量阻尼器。数值分析中采用两轴四自由度车辆模型。本研究考虑了三种行驶模式，即一辆车、两辆并行车辆和两辆连续车辆过桥。采用基于纽马克8法进行数值积分的有限元分析方法。声压级是通过将桥面各有限元表面辐射的声压相加计算得出的。在该计算过程中可以考虑声音的干扰现象。声接收位置为垂直于桥轴线的水平距离为31米，向下距桥跨中心的垂直距离为13米。结果表明，上部结构调谐质量阻尼器的安装可使公路钢桥辐射的低频声对一阶振型降低3~4分贝。据透露，二阶振动模式预计可降低约 7 分贝。较少的