Development of a Non-Gating Guardrail Terminal

Abstract

Guardrail terminals have evolved to the point where they absorb energy while utilizing tension in the rail to countermand the compression. However, non-gating terminals have yet to be developed. In the present study, the possibility of a non-gating guardrail terminal was investigated. Specifically, the combination of lateral and longitudinal forces that produce non-gating performance were determined from computer simulation. Next, a prototype terminal was crash tested at the research team’s laboratory. A terminal head was designed to deform the guardrail, and its internal structure was adjustable to control the longitudinal force. Posts were designed to control lateral forces by modifying their section modulus. This controlled the force at which the posts buckled in response to a collision. A prototype was subjected to two 15° crash tests using an SUV and a small car. In both tests, the kinetic energy of the test vehicle was fully absorbed and the Manual for Assessing Safety Hardware (MASH) criteria would have been met. Neither vehicle passed beyond the terminal head, making these test results the first of their kind.

Performance Case Study of Concrete Bridge-Rail Post on Deck Overhang

“…As such, it was inferred that the inertial resistance of the post was the most significant source of the discrepancy between the calculated post capacity (97.3 k-ft), the effective capacity (116 k-ft), and the lack of observed post distress. The inertial contribution to the capacity of bridge railings was previously suggested by Schrum ( 9 ), but that work alone was not sufficient to explain the results observed in this test. Inertial effects were later investigated using the calibrated LS-DYNA model and are discussed in the relevant section of this report.…”