An Evaluation of the Accuracy of the FTA Approved, Groundborne Noise and Vibration Prediction Model for Rail Transit Systems; A Case Study using Measurements for a New Subway Line

摘要

The groundborne noise and vibration model developed by Nelson and Saurenman in 1984, now recognized by the Federal Transit Administration as the approved model for new transit system facilities, has entered its third decade of use by engineers and consultants in the transit industry. The accuracy of the model has been explored in the past (e.g., Carman and Wolfe). New data obtained for a recently completed extension to a heavy rail transit system provides an opportunity to evaluate the accuracy of the model once more. During the engineering design phase of the project, noise and vibration predictions were performed for numerous buildings adjacent to the new subway line. The predicted values were used to determine the need for and type of groundborne noise and/or vibration control measures. After the start of transit operations, noise and vibration measurements were made inside several of the buildings to determine whether the criteria were achieved. The measurement results have been compared with the values predicted by the model, and indicate that overall vibration levels are in very good agreement, whereas the spectral comparisons indicate differences between measured and predicted values. Conversely, the predicted noise levels were less than the measured levels. Possible explanations for the differences are provided.