AASHTO GSFCM-1

Fracture critical members (FCMs) are defined in the AASHTO LRFD Bridge Design Specifications as steel primary members, or portions thereof, subject to tension whose failure would probably cause a portion of or the entire bridge to collapse. The decision to designate members as FCMs has often been made without considering actual system redundancy or performance of the structure.

Prior to the development of these guide specifications, no standards existed on how to best perform a system analysis to determine performance and response in the event an FCM is assumed to have failed. These assessment procedures apply to typical steel bridges, including simple span and continuous I-girder and tub girder bridges, through-girder bridges, truss bridges, and tied arch bridges.