Development of a MASH TL-3 Approach Guardrail Transition to a MASH TL-4 Steel Bridge Rail
A Manual for Assessing Safety Hardware (MASH) Test Level 3 (TL-3) approach guardrail transition (AGT) was designed to connect the Midwest Guardrail System (MGS) to a MASH TL-4 steel-post, steel-tube, bridge rail, Type IL-OH. Two connection concepts were evaluated using the LS-DYNA finite element analysis computer software. The second concept was selected for further evaluation with full-scale crash testing, which included a previously-developed, thrie-beam, approach guardrail transition, modified HSS8x6x¼ transition tube rails that aligned with the lower and middle bridge rail tubes, and new connection hardware designed to prevent vehicle snag during reverse-direction impacts. The critical impact points were selected using LS-DYNA for MASH test designation nos. 3-20 and 3-21 in the impact direction from the thrie-beam to the bridge rail. MASH test designation nos. 3-20 and 3-21 in the impact direction from the bridge rail to the thrie-beam AGT were determined to be non-critical.
In test no. STBRT-1, the 2,404-lb small car impacted the AGT at a speed of 64.6 mph, an angle of 25.2 degrees, and at a location 21.3 in. upstream from post no. 19, thus resulting in an impact severity of 60.9 kip-ft. The small car was contained and redirected and resulted in a successful test according to MASH test designation no. 3-20 safety performance criteria. In test no. STBRT-2, the 5,007-lb quad cab pickup truck impacted the AGT at a speed of 62.7 mph, an angle of 24.9 degrees, and at a location 15.9 in. upstream from post no. 19, thus resulting in an impact severity of 116 kip-ft. The pickup truck was contained and redirected and resulted in a successful test according to MASH test designation no. 3-21 safety performance criteria.
Highway Safety, Crash Test, Roadside Appurtenances, Compliance Test, MASH 2016, Approach Guardrail Transition, Thrie-Beam Rail, Post-to-Deck, LS-DYNA, FEA, Steel-Tube, Bridge Rail, Roadside Safety, MASH, Crash Testing
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