W-Beam Guardrail Adjacent to a Slope

A W-beam guardrail system was developed and successfully crash tested for use on a 2:1 foreslope. The guardrail design was constructed with W-beam rails 2.66 mm thick (12 gauge) totaling 53.34 m in length, and it incorporated a half-post spacing section of 17.15 m. The W-beam rail was supported by 15 W150 × 13.5 steel posts 1829 mm long, spaced 1905 mm on center, and 19 W150 × 13.5 steel posts 2134 mm long, spaced 952.5 mm on center. Routed, 150 × 200 × 360 mm wood spacer blockouts were used to block the rail away from each post. The research study included bogie testing on steel posts placed in sloped fill, computer simulation modeling with BARRIER VII, and one full-scale vehicle crash test, using a 2000-kg pickup truck. The test, impacting at a speed of 100.7 km/h and an angle of 28.5 degrees, was conducted and reported in accordance with the Test Level 3 (TL-3) requirements specified in NCHRP Report 350. The safety performance of the W-beam barrier system was determined to be acceptable according to TL-3 criteria.