AASHTO GSBSM-1: 2018 [pdf]

AASHTO GSBSM-1: Guide Specifications for Internal Redundancy of Mechanically-Fastened Built-Up Steel Members, 1st Edition with 2022 and 2025 Interim Revisions

It provide an analytical framework to evaluate the internal redundancy of typical steel bridge members, and designate primary steel members as Fracture Critical Members (FCMs) or Internally Redundant Members (IRMs). They describe 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. The Guide Specifications are based on research Transportation Pooled Fund Project TPF-5(253) Evaluation of Member Level Redundancy in Built-Up Steel Members, which addresses the important issues related to performing a credible analysis to identify built-up members that have adequate internal redundancy to resist complete failure of the cross section should one component suddenly fail. The Guide Specifications also include a methodology to establish the interval for inspections specifically intended to identify whether any of the tension components have failed. This inspection is referred to as a special inspection for IRMs and must be of sufficient depth to reliably detect a severed component. This is a major departure from the current calendar-based approach to setting inspection intervals.

Incorporates the 2022 and 2025 interim revisions.

GSBSM-1-UL, GSBSM-1-I2-UL, 978-1-56051-724-5, 9781560517245