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原文传递 Traffic Noise Barrier Overlap Gap Design; Final rept

题名：	Traffic Noise Barrier Overlap Gap Design; Final rept
作者：	Herman, L. A.; Clum, C. M.
关键词：	Traffic noise; Noise pollution control; Barriers; Sound propagation; Highway transportation; Computerized simulation; Vehiclar traffic; Field tests; Acoustic measurement; Environmental impacts; Sound absorbing materials
摘要：	Sound propagation through the gap produced by two parallel vertical barriers with overlapped ends was formulated for traffic noise sources. The method accounts for sound propagated from vehicle source positions for a maximum of ten roadway lanes. Six receiver regions were considered based on potential receiver locations with respect to a gap. The analysis identified both source and receiver regions according to the mechanisms which influence noise propagation in the vicinity of an overlap gap which can result in: direct rays, diffracted rays from the top edge of one barrier, diffracted rays from the top edge of both barriers, rays reflected between the barriers and rays that are both reflected and diffracted. The derived method was implemented in the computer simulation model Gap Analysis Program (GAP). Field measurements for up to 30 receiver positions from four overlap gaps were compared with the uncalibrated predictions made using GAP. The equivalent continuous levels, A-weighted, were overpredicted by 2-3 decibles. When the analysis was based on an octave band characterization of the source, the mean overprediction was reduced to less 1 decibles.
总页数：	218p
报告类型：	科技报告