Noise exposure assessment of over-track buildings induced by train operations

The noise generated by trains running beneath these buildings significantly impacts residents and has garnered growing attention. To evaluate the influence of trains running under buildings on internal noise levels, this study conducted subjective questionnaire surveys and field measurements for noise and vibrations in two buildings located in Wuhan and Shenzhen, China. The subjective annoyance of noise was investigated through a survey conducted with a total of 152 participants. The measurement points were positioned at the 2nd-floor level in close proximity to the building's support structures, as well as on the various floors. The contribution of airborne noise and structure-borne noise to the acoustic environment was identified, elucidating their respective impacts on the overall soundscape. Furthermore, an investigation was conducted to examine the correlation between structure-borne noise and floor vibrations, which was then compared with the guidelines provided by FTA (Federal Transit Administration). The results found that the indoor noise within the over-track building, resulting from train operations, mainly stems from structure-borne noise characterized by a frequency-dependent correlation among floor vibrations. This phenomenon is predominantly observed below 200 Hz with prominent peaks specifically at 40 Hz. The utilization of the FTA (Federal Transit Administration) recommended formula for predicting structure-borne noise levels based on velocity levels may result in an underestimation of the noise impact, particularly with regard to noise energy above 100 Hz. These findings hold significant implications for the design and construction of similar over-track buildings.