Dynamic response evaluation of tall noise barrier on high speed railway structures

The aim of this paper is to obtain a fundamental understanding of the dynamic response of tall noise barriers during the passage of high speed train and to develop a practical method for evaluating this in anticipation of planned increases in running speed in the future. Tall noise barriers recently installed on Japanese high speed railway structures have a low natural frequency; therefore, they may resonate with the train draft pressure that up until now has not been a crucial condition for practical design. As a result of field measurements and numerical simulations, it was found that the dynamic response of noise barriers excited by passing trains can be explained by the resonance effect between pulse excitation of the train draft and the natural frequency of the noise barriers and by the tail-pulses overlap effect. Methods to generalize the resonance effect with the multi-body system and the tail-pulses overlap effect with the free vibration theory of the single-degree-of-freedom system were shown. Finally, two design methods were proposed: a precise method based on simulation and a simple method based on static design load. The simple method uses a design train draft pressure which is a function of noise barrier natural frequency when train speed is 260 m/h or 360 m/h.