Development of a MASH Test Level 4 Open Concrete Bridge Rail
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ABSTRACT
An open concrete bridge rail was developed according to safety performance guidelines in the American Association of State Highway Transportation Officials (AASHTO) Manual for Assessing Safety Hardware (MASH) for Test Level 4 (TL-4). Systems designed and developed under previous safety guidance were reviewed, and their geometry and crash testing performance were used to establish the geometry of the new bridge rail. Yield-Line Theory and the AASHTO Inelastic Post and Beam design methods were modified and utilized to determine the capacity of the new open concrete bridge rail. Both 36-in. and 39-in. tall variants of the new open concrete bridge rail were configured. Both variants incorporated a 27-in. tall by 14-in. wide rail, supported by 36-in. long x 10 in. wide posts in the interior region, and 72-in. long posts in the end region. Posts in both regions were separated by a 72-in. long gap. Posts in the 36-in. tall variant were 9 in. tall, and posts in the 39-in. tall variant were 12 in. tall. Three bridge deck reinforcement configurations were developed to provide different reinforcement patterns that were compatible with the new bridge rail. Three full-scale crash tests were recommended to be conducted under MASH test designation nos. 4-10, 4-11, and 4-12 to evaluate the safety performance of the new open concrete bridge rail.
KEYWORDS
Highway Safety, Roadside Appurtenances, MASH 2016, Open Concrete Bridge Rail, Roadside Safety, Bridge Deck, Design, Analysis, Inelastic Analysis