Fracture Critical Members- Floorbeams
Fracture Critical Members- Floorbeams
(OP)
In the BIRM. Ref. BIRM pg 10.2.7
Floor Beams: A floorbeam may be fracture critical if it satisfies one or more of the following. Some states consider any floor beam to be fracture critical even if none of the following criteria are met. So, most FB are considered FC unless FE model proves otherwise.
• Flexible or hinged connection to support at the girder/floorbeam connection.
• Floorbeam spacing greater than 14ft
• No stringer supporting the deck
• Stringers are configured as simple beams
With no stringers supporting the deck at what spacing does it become (by inspection) that the floorbeams can be considered redundant and can no longer need to be inspected as FC members?
Can anyone give background on how the 14ft criteria is based on?
Thank you
Floor Beams: A floorbeam may be fracture critical if it satisfies one or more of the following. Some states consider any floor beam to be fracture critical even if none of the following criteria are met. So, most FB are considered FC unless FE model proves otherwise.
• Flexible or hinged connection to support at the girder/floorbeam connection.
• Floorbeam spacing greater than 14ft
• No stringer supporting the deck
• Stringers are configured as simple beams
With no stringers supporting the deck at what spacing does it become (by inspection) that the floorbeams can be considered redundant and can no longer need to be inspected as FC members?
Can anyone give background on how the 14ft criteria is based on?
Thank you





RE: Fracture Critical Members- Floorbeams
I think a girder floorbeam system with 14' floorbeam spacing and no stringers would always be FC.
RE: Fracture Critical Members- Floorbeams
I agree with Bridgebuster that 14' spaced floorbeams w/o stringers are always FC. Some redundancy could be provided by a deck system, but in most cases the deck will be jointed over the floorbeam, or every second floorbeam.