Development of a 7.62-m Long Span Guardrail System
REPORT NUMBER
TRP-03-072-99
AUTHORS
Karla Lechtenberg (Polivka), Bob Bielenberg, Dean Sicking, Ronald Faller, John Rohde
PUBLICATION DATE
1999-04-06
ABSTRACT
<p>A 7.62-m long span guardrail system was developed for use over low-fill culverts. The long span design was constructed with two 2.66-mm (12-gauge) thick nested W-beam rails totaling 30.48 m in length. The nested W-beam rail was supported by sixteen W150x13.5 steel posts and six standard CRT posts, each measuring 1,830-mm long. Post spacings were 1,905-mm on center except for the 7.62-m spacing between the two CRT posts surrounding the unsupported span. The research study included computer simulation modeling with BARRIER VII and full-scale vehicle crash testing, using 3/4-ton pickup trucks. The first test, impacting at a speed of 101.3 km/hr and an angle of 25.4 degrees, was unsuccessful because the barrier system failed at the simulated BCT anchorage end. Consequently, the long-span barrier system was modified to include additional guardrail posts and new BCT anchorage hardware. The second test, impacting at a speed of 102.7 km/hr and an angle of 24.5 degrees, was unsuccessful due to vehicle rollover. The safety performance of the long-span barrier system was determined to be unacceptable according to the Test Level 3 (TL-3) evaluation criteria specified in NCHRP Report No. 350, Recommended Procedures for the Safety Performance Evaluation of Highway Features.</p>
KEYWORDS
<p>Highway Safety, Guardrail, Roadside Appurtenances, Longitudinal Barrier, Box Culvert, Crash Test, Compliance Test</p>
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