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Crash Testing and Evaluation of HDOT’s Thrie-Beam Approach Guardrail Transition Attached to 42-in. Tall, Solid Concrete Bridge Rail with Aesthetic, Recessed, Rounded Panels and 6-ft Wide Sidewalk: MASH Test Nos. 3-20 and 3-21




Tewodros Yosef, Joshua Steelman, Ronald Faller, Erin Urbank




This report documents two full-scale crash tests conducted to evaluate the safety performance of the Hawaii Department of Transportation’s (HDOT’s) Thrie-Beam, Approach Guardrail Transition (AGT) attached to the 42-in. tall, solid concrete bridge rail with aesthetic, recessed, rounded panels and 6-ft wide sidewalk according to the Test Level 3 (TL-3) criteria of the Association of State Highway and Transportation Official (AASHTO) Manual for Assessing Safety Hardware, Second Edition (MASH 2016). The AGT consisted of nested thrie-beam rail supported by W6x15 and W6x8.5/W6x9 steel posts and was attached to a reinforced concrete buttress and 42-in. tall solid concrete bridge rail. The upstream section included the Midwest Guardrail System (MGS) stiffness transition utilizing an asymmetrical W-to-thrie transition segment to ensure a crashworthy connection between the upstream W-beam and the downstream nested thrie beam. The thrie-beam AGT was full-scale crash tested in conjunction with a 6-in. tall curb placed below the thrie-beam rail. Test nos. H42ST-1 and H42ST-2 were conducted in accordance with MASH 2016 test designation nos. 3-21 and 3-20, respectively. In test no. H42ST-1, a 2270P pickup truck impacted the barrier at a speed of 64.7 mph and an angle of 24.8 degrees. Although the impact speed exceeded the MASH limits, MASH accepts values in excess of the criteria for longitudinal barriers. In test no. H42ST-2, an 1100C small car impacted the barrier at a speed of 62.4 mph and an angle of 25.1 degrees. In both tests, the thrie-beam AGT successfully contained and safely redirected the vehicles. All occupant risk measurements were found to be within the established MASH 2016 limits. Therefore, test nos. H42ST-1 and H42ST-2 were deemed to have satisfied all safety performance criteria, and the HDOT thrie-beam AGT attached to the 42-in. tall, solid concrete bridge rail with aesthetic, recessed, rounded panels and 6-ft sidewalk was determined to be crashworthy to MASH 2016 TL-3.


Highway Safety, Crash Test, Roadside Appurtenances, Compliance Test, MASH 2016, Approach Guardrail Transition, Thrie-Beam, Concrete Parapet, Sidewalk, Concrete Bridge Rail

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