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Development of a MASH Test Level 4 Steel, Side-Mounted, Beam-and-Post, Bridge Rail




Oscar Pena, Ronald Faller, Jennifer Rasmussen (Schmidt), Joshua Steelman, Scott Rosenbaugh, Bob Bielenberg, Pascual Mauricio, Jared Duren




A new steel, side-mounted, beam-and-post, bridge rail was designed, crash-tested, and evaluated according to safety performance guidelines included in the American Association of State Highway and Transportation Officials Manual for Assessing Safety Hardware, Second Edition (MASH 2016) for Test Level 4 (TL-4). The new bridge rail system was designed to be compatible with multiple concrete bridge decks utilized by the States of Illinois and Ohio. Bridge rail configurations were designed and optimized based on weight per foot, constructability, and safety. Post-to-rail and rail-to-rail connections were designed for the new bridge rail. Several concepts for these connections were configured, and after discussion with representatives from Illinois and Ohio Departments of Transportation, a preferred concept was selected for full-scale crash testing with a single-unit truck (SUT), a pickup truck, and a small car. The new bridge rail consisted of three tubular steel rail elements supported by W6x15 (W150x22.5) steel posts mounted to the exterior, vertical edge of the concrete deck and spaced at 8 ft (2.4 m) on centers. The top rail element was an HSS 12-in. x 4-in. x ¼-in. (HSS 304.8-mm x 101.6-mm x 6.4-mm) and the lower two rail elements were HSS 8-in. x 6-in. x ¼-in. (HSS 203.2-mm x 152.4-mm x 6.4-mm). The centerline heights of the rail elements were 37 in. (940 mm), 28 in. (711 mm), and 16 in. (406 mm) above the surface of the deck for the top, middle, and bottom rails, respectively. Four MASH 2016 TL-4 crash tests were performed on the new bridge rail, which successfully contained and redirected each of the MASH 2016 TL-4 vehicles. All occupant risk measures and evaluation criteria were within MASH 2016 limits. In the initial run of test designation no. 4-12, test no. STBR-1 with the SUT, the impact severity did not meet the minimum limit of 142.0 kip-ft (180.6 kJ). Thus, test designation no. 4-12 was re-run in test no. STBR-4, and the results met all MASH 2016 impact safety criteria, ensuring that the new bridge rail meets MASH 2016 TL-4 standards.


Highway Safety, Crash Test, Roadside Appurtenances, Compliance Test, MASH 2016, TL-4, Bridge Rail, Side-Mounted, Beam-and-Post

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