This paper proposes a prediction method to estimate vibrations in building structures induced by to-be-constructed railways. The method derives modal equations of motion for building modeling by using the natural frequencies in limited modes, the corresponding damping ratios and mode shapes at selected locations. The participation vector for input ground motions is approximated by the corresponding mode shapes. Those modal properties can be obtained from ambient vibration testing, and hence the modeling does not require design documents to construct the mass, damping and stiffness matrices. The railway-induced motions at the column bases can be estimated priorly, and the dynamic responses at the selected locations are subsequently predicted by mode superposition. The fundamental characteristics of the proposed prediction method are studied by numerical simulations. The simulation result shows high participation-vector approximation accuracy when using few lower mode shapes at few locations; Higher modes exhibit more complicated mode shape amplitude distribution, and thus mode shapes at more locations are required for the sufficient approximation accuracy; Compared with seismic response calculation in the horizontal directions where few lower modes are sufficient, higher modes are required for satisfactory prediction accuracy. The method provides an alternative approach for predicting railway-induced vibrations and is helpful when design documents of the objective building are unavailable. The findings from the simulation provide guidance to the measurement-point design and the objective modes to identify in the implementation of the proposed method.

中文翻译：

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利用有限模态模态特性预测建筑结构中铁路诱发振动的方法


本文提出了一种预测方法来估计待建铁路引起的建筑结构振动。该方法通过使用有限模式中的固有频率、选定位置的相应阻尼比和振型来导出用于建筑建模的运动模态方程。输入地面运动的参与向量由相应的振型近似。这些模态特性可以从环境振动测试中获得，因此建模不需要设计文件来构建质量、阻尼和刚度矩阵。可以预先估计柱底处的铁路引起的运动，然后通过模态叠加来预测所选位置的动态响应。通过数值模拟研究了所提出的预测方法的基本特征。仿真结果表明，在少数位置使用少量较低模态振型时，参与向量逼近精度较高；模态越高，模态振幅分布就越复杂，因此需要更多位置的模态形状才能获得足够的近似精度；与水平方向的地震响应计算需要很少的低阶模态相比，需要更高的模态才能获得令人满意的预测精度。该方法提供了一种预测铁路引起的振动的替代方法，并且在目标建筑的设计文件不可用时很有帮助。仿真结果为测量点设计和在所提出方法的实施中确定的目标模式提供了指导。