The American Association of State Highway and Transportation Officials has issued 2025 interim revisions for its Guide Specifications for Internal Redundancy of Mechanically-Fastened Built-Up Steel Members, 1st Edition, first published in 2018.
[Above image by AASHTO]
That guide provides an analytical framework to evaluate the internal redundancy of typical steel bridge members and designates primary steel members as either fracture critical members (FCMs) or internally redundant members (IRMs).
The guide also describes a procedure for evaluating the internal redundancy of the built-up tension members of the tension components of flexural members and axially loaded tension members.
AASHTO noted that its 2025 Interim Revisions to that guide include new rules finalized by the Federal Highway Administration in 2022 that pertain to the National Bridge Inspection Standards, including replacing FCM with the term “nonredundant steel tension member” or “NSTM.”
AASHTO added that it is necessary to have the 2025 Interim Revisions, as well as the 2022 Interim Revisions, to have all current specification information for this particular guidebook.
To order a copy of the new interim revisions, visit the online AASHTO Store online and search by the publication’s item code, GSBSM-1-I2, or visit the specific ordering webpage for the revisions by clicking here.
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