AN INVESTIGATION OF THE SUITABILITY OF LAKE STATES TIMBER SPECIES FOR GUARDRAIL POSTS: PHASE I. SPECIFICATION FOR LAKE STATES GUARDRAIL POSTS

Wood has a number of properties which make it suitable for guardrail posts and blocks, one of the most important being its reaction to dyanamic loads such as a guardrail post may experience. The major factor in the use of a certain material for guardrail posts will be economics, or the cost of the post. In order that the wooden post provide the function that it was intended for, it is necessary to use high quality material and high quality preservative treament. The specification requires the use of grade stamped posts indicating grade and species requirements have been met, and the use of brands to indicate treating requirements have been met. The new MDOT specification allows the use of a number of Lake States species at high quality levels, as well as Douglas-fir and southern pine. Because the specifications are quite comprehensive both for the wood and for the preservative treatment it is felt that the new document will do much to improve the quality of guardrail posts in the State of Michigan and increase driver safety. The specification could act as a model for other states. (Author)