Welded Moment Conn Backing Bar
Welded Moment Conn Backing Bar
(OP)
Involved in a project in a non-seismic region with field welded (CJP flanges) moment connections. Erector is using backing bars and wants to leave them in-place. I see a lot of information saying this is not permitted for seismic or fatigue conditions but is it acceptable for a non-seismic moment frame system.
Thanks,
Thanks,





RE: Welded Moment Conn Backing Bar
RE: Welded Moment Conn Backing Bar
RE: Welded Moment Conn Backing Bar
RE: Welded Moment Conn Backing Bar
This is also why rough, flame cut access holes are prohibited in fatigue applications. Each notch is a focal point for local stress. The risk of fatigue, as a mechanism for failure, increases as the stress in the metal increases, beginning at around half of yield.
RE: Welded Moment Conn Backing Bar
Keep in mind that welding without backing requires a higher level of qualification than welding with a backing.
Most often, rejectable weld anomalies occur at the root of a CJP weld. These are most commonly lack of penetration and poor fusion. While other anomalies may occur (inclusions, porosity,etc.), these are common.
RE: Welded Moment Conn Backing Bar
The seismic specification, section 11.2a, says the same thing for the cases where the backing bar is removed.