This paper describes the relative acoustical performances established by scale model testing of a number of relatively novel noise barriers in typical highway situations. The various barriers were thin, wide, t-profiled, cylindrically topped, corrugated, inclined, y-profiled, arrow-profiled and of the thnadner principle, and some were treated with sound absorptive material. The highway situations involved a single barrier with a protected receiver (ie, a receiver behind the barrier), a single barrier with a receiver on the opposite side of the highway, and parallel barriers, one on each side of the highway. In the single barrier, protected receiver case, higher noise reduction was found for wide top barriers, especially those of t-profile, and especially t-profile absorptive top barriers with cap widths of 0.6 m (2 ft) or more and of small cap thickness. Absorptive side treatment was effective in reducing a small, but measurable sound increase found when a reflective sided barrier is installed on the opposite side of the highway to receivers, and in reducing the degradation in performance that occurs when there is a barrier on each side of the highway rather than on just one. (A)
Abstract