ACI 318 Questions
ACI 318 Questions
(OP)
Hey all
Hope everyone is ok,I have couple of questions to ask
1. Where is the threshold in the code to distinguish between beam- column and column in design, or in other words what is the biggest axial force that we can ignore and consider the beam-column as a beam
2.Generally speaking if we ignore torsional in design the building will stay safe with some cracks(taking only compatibility torsion not equilibrium torsion ) is this right???
3. after Etabs distribute slab force in beams, how can I calculate the redistributed force on beam ???
Thank you all
Hope everyone is ok,I have couple of questions to ask
1. Where is the threshold in the code to distinguish between beam- column and column in design, or in other words what is the biggest axial force that we can ignore and consider the beam-column as a beam
2.Generally speaking if we ignore torsional in design the building will stay safe with some cracks(taking only compatibility torsion not equilibrium torsion ) is this right???
3. after Etabs distribute slab force in beams, how can I calculate the redistributed force on beam ???
Thank you all






RE: ACI 318 Questions
You can ignore compatibility torsion. Not all torsion. But you have to be consistent when you ignore it and make sure that you do not rely on it in other areas of the design.
You should not ignore any torsion in a sway frame as the sway stiffness is relying on it!
RE: ACI 318 Questions
BA
RE: ACI 318 Questions
RE: ACI 318 Questions
Does it mean if we use equivalent column in slab design for one way beam & slab system, we have to design the beam for torsion?
Thanks
RE: ACI 318 Questions
To answer your questions:
1. Element can be designed as a beam if axial stress is less than 0.1fc' or 0.1fc'(Ag) in terms of force
2. Generally, RC beams in buildings will not resist any torsion. unless it is applied by an external load (e.g. cantilever slab without a back span)
3. Moment redistribution in the ACI code, as with all other codes, is a clause to redistribute the moment from the support and transfer it to the midspan moment. The purpose of this is to reduce the rebar requirement at supports, inorder to avoid rebar congestion at beam/column joints.
RE: ACI 318 Questions
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