Problems with the Performance of Wooden Noise Barriers

About the report:

In September 1984, the Research Council was requested by the Virginia Department of Highways and Transportation to conduct an investigation into the problems experienced with wooden noise barriers. Some of these barriers warped even before construction was completed, and gaps and splits were noted within a short period of time. A questionnaire survey of eleven states that have constructed noise barriers revealed that these problems are widespread. An analysis of the responses to the questionnaire has led to three basic recommendations. The first of these recommends upgrading the overall quality of the material used in the construction of the wooden barriers. This includes raising the grade of wood required and lowering the moisture content, as well as specifying maximum moisture contents for the wood both before and after treatment. Next, it is recommended that simple changes be made in the design of barriers. Technical alterations such as additional braces, fitted joints, overlapping joints, and angled nailing would help preserve their shape. Also, the use of plywood rather than planks would minimize the number of joints. The third recommendation is that specifications be strictly enforced. Wood, with its tendency to warp and shrink, must be handled correctly if it is to provide a noise barrier that will be effective over a long period of time.

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