Evaluation of the Midwest Guardrail System (MGS) with White Pine Wood Posts
REPORT NUMBER
TRP-03-241-11
AUTHORS
Cale Stolle, Karla Lechtenberg (Polivka), Ronald Faller, Scott Rosenbaugh, Dean Sicking, John Reid
PUBLICATION DATE
2011-03-28
ABSTRACT
Wood-post guardrail systems have performed acceptably when redirecting errant vehicles, utilizing 6-in. x 8-in. (152-mm x 203-mm) southern yellow pine (SYP) posts. SYP wood posts have been used due to their relatively low cost. State departments of transportation have expressed a desire to use various species of wood in their wood post guardrail systems, including white pine and red pine. White and red pine posts have lower strength than the SYP post typically used in guardrail design. This would generally be cause for concern as wood posts are designed to have sufficient capacity to rotate in the soil and absorb energy without fracturing. The recently developed Midwest Guardrail System (MGS) imparts lower forces on its posts than traditional W-beam guardrail systems, thus there is a potential for lower-strength, wood guardrail posts to be used. The white pine wood post, with the same cross-sectional dimensions as standard southern pine wood posts, was chosen to be evaluated in the MGS system.
The white pine wood post MGS system was evaluated according to the Test Level 3 (TL-3) criteria set forth in the Manual for Assessing Safety Hardware (MASH). The research study included one full-scale vehicle crash test with a Dodge Ram Quad Cab pickup truck, weighing approximately 5,000 lb (2,268 kg). Following the successful redirection of the pickup truck, the safety performance of the white pine wood post MGS system was determined to be acceptable according to the TL-3 evaluation criteria specified in MASH.
KEYWORDS
Highway Safety, Crash Test, Roadside Appurtenances, Compliance Test, MASH, MGS, White Pine Wood, Longitudinal Barrier