Jacking Design
Jacking Design
(OP)
I just finished a jacking design and received a comment regarding local flange bending with a sheet of documentation from a unknown source. I looked back at the AISC Steel Construction Manual (13th ED) in section J10 (Flanges and Webs with concentrated forces) and noticed some literature that disagrees with the comment. 16.1-355 states that "Single concentrated forces may be tensile (such as those delivered by tension hangers) or compressive (such as those delivered by bearing plates at beam interior positions, reactions at beam ends , and other bearing connections). Flange local bending applies ONLY for tensile forces."
SO based on this language from the AISC Manual it is MY understanding that Flange Local Bending does not need to be checked for my jacking design (since it is going to be a compressive force delievered by a bearing plate at interior positions and beam ends). I did check web crippling and yielding.
Does anyone have any input to what could validate this comment or do I have a pretty good leg to stand on to argue the comment?
SO based on this language from the AISC Manual it is MY understanding that Flange Local Bending does not need to be checked for my jacking design (since it is going to be a compressive force delievered by a bearing plate at interior positions and beam ends). I did check web crippling and yielding.
Does anyone have any input to what could validate this comment or do I have a pretty good leg to stand on to argue the comment?






RE: Jacking Design
RE: Jacking Design
Michael.
Timing has a lot to do with the outcome of a rain dance.
RE: Jacking Design
BA
RE: Jacking Design
If your load path involves bearing directly onto the complete underside of the beam your web stiffness in comparison to the flange stiffness is going to ensure that basically all of the load goes directly into the web unless you install some kind of stiffeners. As long as your assumptions are based on that, you should be fine. If you've got a torsional moment of some sort, or an uplift, or anything else that might throw part of your connection into tension then the situation changes.
RE: Jacking Design
"Although this deformation could also occur under compressive normal forces, it is customary that flange local bending is checked only for tensile forces (because the original concern was weld fracture). Therefore it is not required to check flange local bending for compressive forces."
Earlier on in this section, they discuss how this provision was initially intended for moment connections to ensure the flange is rigid enough as to limit local deformation, and preclude the chance of flange local buckling.
It does state it is not required to check for flange local buckling, not neccesarily that it is not applicable.