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https://nap.nationalacademies.org/catalog/27432/critical-issues-in-transportation-for-2024-and-beyond

In-Service Performance Evaluation of NETC Steel Bridge Railings

The predominate bridge rail and approach guardrail transition (AGT) systems used in New England include details for 2-bar, 3-bar and 4-bar designs. Steel bridge rail details which were developed and tested under the auspices of the New England Transportation Consortium (NETC). The tests were performed in compliance with the American Association of State Highway and Transportation Officials (AASHTO) Guide Specifications for Bridge Railings Performance Level 2 (GSBR PL2) and/or National Cooperative Highway Research Program (NCHRP) Report 350 (R350) test procedures. These steel bridge rail systems have been used in the New England states for more than 20 years. According to the joint agreement between AASHTO and the Federal Highway Administration (FHWA), each state is required to specify Manual for Assessing Safety Hardware (MASH) compliant bridge rails for new and full replacements on the National Highway System (NHS) with contract lettings after December 31, 2019. In accordance with those requirements, a project was recently completed to evaluate the crash performance of the New England steel bridge rail systems under the MASH criteria using finite element analysis. The study concluded that the existing designs would meet the new crash testing standards, but also recommended minor design modifications to further improve performance. Establishing that these long-standing designs are performing well in the field would provide further confidence that the current, as well as the improved, designs adequately meet the higher performance criteria of MASH without further full-scale testing. While the in-service performance of the NETC steel bridge railings is believed to be good, an in-service performance evaluation (ISPE) has never been conducted. The study will focus essentially on the evaluation of the actual in-service performance of the steel bridge railings in New England that were developed under NETC. The results from this research are expected to confirm the assumption that the in-field performance of the NETC Steel bridge railings is matching or is close to the design criteria.