AN INVESTIGATION OF NOISE FROM TRAINS ON BRIDGES

The introduction of new railway systems in urban areas to ease road tr affic congestion has led to concerns about the noise from trains, part icularly as tracks often pass close to residential dwellings. One spec ific issue relates to the noise from trains or trams on bridges. The b ridge design and construction can increase noise levels above those wh en the track is at grade. This paper addresses this issue, and reports two case studies to quantify the contributions to the total noise lev el from the wheel/rail noise, and from the noise radiated by the bridg e structure itself including both the deck and the parapets. The studi es involved, in the first case, consideration of the design and constr uction of a concrete and steel bridge and a comparison of pre-construc tion predictions, supported by finite element analysis, with in-use no ise measurements. The second case involved noise and vibration measure ments on an existing bridge to quantify the noise from the different s ources, to compare simple predictions with measured noise levels, and to evaluate the effectiveness of various noise control measures. The g ood agreement between the predicted and measured levels in both case s tudies has led to the conclusion that the techniques provide a cost-ef fective method for the prediction of noise levels with an acceptable d egree of accuracy. The techniques can also be used to evaluate the ben efits to be gained from alternative noise and vibration control measur es, and thus to define the most cost-effective control measure prior t o implementation. (C) 1996 Academic Press Limited