Sound barrier for tracked vehicles - consists of main concrete type wall with very porous low density fibrous plastic faced sheet attached to side nearer to tracks

摘要

A sound barrier which absorbs noise emissions from vehicles, and partic. those running on tracks consists of wall sections running along the route of the traffic and constructed of aggregates such as ballast, chippings etc. and hydraulic binder, with their sides facing the source of noise having a textured surface. This surface has a covering over at least part of its area of a porous material whose density is low and (partic.) is only half that of the barrier itself. The joins between barriers include pref. elastomer sound absorbers such as rubber, polypropylene, silicone rubber, polyurethane foam. The barrier (1) is parallel to the tracks (3) and is made of the main wall (4) of 120 mm thick concrete. Individual walls are joined by an H-section with intermediate sound-absorbing elastomer layers. The structure has no direct connection between the concrete foundation (6) and that (2) of the rails. The wall (4) is 3.12 m from the centre line of the tracked vehicles, and it (4) stands in a bed (7). ADVANTAGE - The barriers take up little space and can therefore be used in heavily populated areas. They have a high sound absorption and only low sound reflection. The deg. of sound absorption can be adjusted to optimum level to suit the frequency band concerned by varying the gap between the barrier and porous covering.