Discussion. Road Construction Noise Measurement, Prediction and Control.

Abstract

Dr Martin states that on most road construction schemes the main noise problem arises from plant used in bulk earthwork operations. While this may be correct for roadworks undertaken within rural and semi-urban areas, for major urban road construction the noise from piling work is quite often the predominant problem because the noise source in such operations is much closer to inhabited properties than is the case with earthmoving processes.57. Equation (2) indicates that for construction operations which approximate to a line source, the noise attenuation due to the distance between source and receiver (4 is proportional to 10loglo (d/B), where B is the angle subtended by the operation at the receiver. For a point source the distance attenuation is 2O10gl0 d. When the distance d is much larger than the length of the line source the distance attenuation values predicted by the two preceding expressions are the same.According to Dr Martin, when d is less than 60 m the two expressions generate different values of the distance attenuation. However, he does not give any indication of the magnitude of the error which can occur due to treating a line source as a point source, and I was wondering if he has any such data.58. Although the distance attenuation component in equation (2) may be more accurate, for earthmoving operations, than that for a point source, it does require the estimation of an additional unknown factor (i.e., B) for anyone undertaking noise level predictions. In addition, for any quoted value of L,, to be of practical use, the reference distance ( R ) and the angle subtended by the operation at the reference position (4) must be specified. Dr Martin does not quote values of the latter parameter for the data reported in Table 1. Is it possible to obtain this supplementary information?59. With regard to the control of road construction noise, the vital importance of pre-contract estimations must be stressed, as must the roles of the Engineer and the Contractor in combating the nuisance due to construction noise.60. At the design stage the Engineer should make preliminary estimates of construction noise for the projected scheme. The values so derived will only be approximate since at this stage the contractor's construction methods and phasing of work will not be known. However, the noise level estimates will indicate whether the work can be carried out using conventional plant and methods of construction,