Performance Evaluation of KDOT W-Beam Systems, Volume I, II
Jim Holloway, Mark Bierman, Brian Pfeifer, Barry Rosson, Dean Sicking
Four full-scale vehicle crash tests were performed on steel post W-beam guardrail installations for the Kansas Department of Transportation to determine the safety performance of the guardrail systems and the deflection characteristics due to nesting of the W-beam and reducing the post spacing. The four test installations that were evaluated consisted of: (1) a single W-beam with 6 ft - 3 in. post spacing; (2) a nested W-beam with 6 ft - 3 in. post spacing; (3) a single W-beam with 3 ft - 1 1/2 in. post spacing; and (4) a nested W-beam with 3 ft - 1 1/2 in. post spacing. The impact conditions for all four crash tests consisted of using a 4500-lb sedan impacting at 60 mph and 25 degrees. The tests were conducted and reported in accordance with the requirements specified in the Recommended Procedures for the Safety Performance Evaluation of Highway Appurtenances, National Cooperative Highway Research Program (NCHRP) Report No. 230. The safety performance of each guardrail system was determined to be acceptable according to the NCHRP Report 230 criteria. The impact characteristics of the guardrails and vehicles from the full-scale crash tests will be used to aid in the decisions for the placement of W-beam guardrail. These results will also be used in the second phase of this study (Volume II), which utilizes component testing and computer simulation to predict the behavior of the same types of systems with wood posts instead of steel.
Highway Safety, Crash Tests, Guardrail, Posts, Dynamic Post Testing, W-Beam
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