Abstract
Computer simulation and physical testing of posts and guardrail installations were performed to develop a W-beam guardrail system for installation where bedrock is within the normal embedment depth of the posts. Computer simulation was conducted with BARRIER VII to determine optimal post force-deflection properties and the critical impact point for a full-scale vehicle crash test. Physical testing included dynamic testing of posts in various embedment configurations and one full-scale vehicular crash test, which was performed according to the Test Level 3 criteria specified in NCHRP Report 350. Steel W152 X 13.4 (W6 X 9) posts were embedded into an elongated hole drilled into rock and backfilled with ASTM C33 coarse aggregate, size No. 57. The elongated hole was created by drilling three holes 203 mm (8 in.) in diameter on 165-mm (6.5-in.) centers. The full-scale crash test, which was performed with a 2,000-kg pickup truck, was used to verify the safety performance of the design for situations where bedrock is encountered on the surface of the ground. Guidelines based on dynamic post testing were developed for use when the bedrock is encountered at various depths below the surface.
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