Mechanical & Materials Engineering, Department of
First Advisor
Cody S. Stolle
Date of this Version
4-2024
Document Type
Article
Citation
A thesis presented to the faculty of the Graduate College at the University of Nebraska in partial of fulfillment of requirements for the degree of Master of Science
Major: Mechanical Engineering and Applied Mechanics
Under the supervision of Professor Cody S. Stolle
Lincoln, Nebraska, December 2023
Abstract
The Hawaii Department of Transportation (HDOT) desired to evaluate the crashworthiness of a guardrail end terminal design in which the upstream guardrail anchorage was connected to a block partially buried in a cut slope, known as a “Buried in Backslope” or BIB design. The HDOT BIB system used an upper W-beam with 8-in. deep blockouts attached to W6x9 steel posts and a lower W-beam rubrail located 3 in. below the upper rail. The system used two horizontal flares: 7.4:1 near the upstream anchor block and a 13:1 flare through the ditch.
Critical impact points (CIPs) were identified and recommended for full-scale crash testing in the standard and reverse directions of travel. Test no. HBIB-1 consisted of a small car impacting 12 in. downstream from the upstream anchor block at 62 mph and 15 degrees. The small car snagged on several steel posts below the rubrail and experienced excessive ridedown decelerations of -27.59 g’s, and the right-side A-pillar was crushed. Test results were unsatisfactory to MASH evaluation criteria.
The system was redesigned with a vertical height transition and rubrail blockouts. The system was retested with the same impact conditions in test no. HBIB-2 as HBIB-1, and the vehicle was successfully and safely redirected. Additional full-scale crash tests performed using a 2270P pickup truck and 1100C small car at different CIPs were also successful. Full-scale crash testing in the reverse direction is also recommended to confirm the crashworthiness of the system.
Advisor: Cody S. Stolle
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Comments
Copyright 2023, Sina Changizian. Used by permission