Development of a Low-Cost, Energy-Absorbing Bridge Rail
A new, low-cost bridge rail was designed to be compatible with the Midwest Guardrail System (MGS) such that an approach transition would not be required between the two barriers. It was desired that the system minimize bridge deck and rail costs. Several concepts for an energy-absorbing bridge post were developed and tested. These concepts included strong-post systems designed with plastic hinges and weak-post systems designed to bend near the attachment to the bridge deck. The final post concept incorporated S3x5.7 (S76x8.5) steel sections which were designed to bend at their bases. Each post was housed in a socket placed at the vertical edge of the deck and anchored to the deck with one through-deck bolt. A W-beam section was used as the rail element and was attached to the posts with a bolt that was designed to break during an impact event. Two full-scale crash tests were performed according to the Test Level 3 impact conditions provided in the Manual for Assessing Safety Hardware (MASH), in which the system successfully met all safety performance criteria. The dynamic deflection of the new bridge rail and BARRIER VII modeling demonstrated that the new bridge rail would not require a transition when used with the MGS.
Highway Safety, Crash Test, Roadside Appurtenances, Compliance Test, MASH, Longitudinal Barrier, Bridge Rail, Approach Transition, MGS
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