Corbel or Cantilevered beam
Corbel or Cantilevered beam
(OP)
Folks,
This may seem to be a stupid question, but can anyone offer an explanation:
I have a stub column which is to be designed to carry a horizontal reaction. It has no axial load on it, meaning it is a cantilevered beam. The stub is 3'-0" high and 4'-0" wide and 2'6" deep.
My options are to design it as a cantilever beam and provide shear reinforcing parallel to the direction of force or to design it as a corbel and provide closed hoops perpendicular to the direction of shear. It may be cast at a different time, with rebar already doweled in during the first pour.
How do I decide which method to design it by?
This may seem to be a stupid question, but can anyone offer an explanation:
I have a stub column which is to be designed to carry a horizontal reaction. It has no axial load on it, meaning it is a cantilevered beam. The stub is 3'-0" high and 4'-0" wide and 2'6" deep.
My options are to design it as a cantilever beam and provide shear reinforcing parallel to the direction of force or to design it as a corbel and provide closed hoops perpendicular to the direction of shear. It may be cast at a different time, with rebar already doweled in during the first pour.
How do I decide which method to design it by?






RE: Corbel or Cantilevered beam
RE: Corbel or Cantilevered beam
Given your shape described, this is certainly not shaped like a beam, it is a corbel.
I would use strut and tie.
Cheers,
YS
B.Eng (Carleton)
Working in New Zealand, thinking of my snow covered home...
RE: Corbel or Cantilevered beam
Moment arm of 18"
RE: Corbel or Cantilevered beam
/ / |
/____/ / <--- direction of force
| | /
| |/
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RE: Corbel or Cantilevered beam
strut and tie.
RE: Corbel or Cantilevered beam
RE: Corbel or Cantilevered beam
RE: Corbel or Cantilevered beam
RE: Corbel or Cantilevered beam
RE: Corbel or Cantilevered beam
RE: Corbel or Cantilevered beam
RE: Corbel or Cantilevered beam
RE: Corbel or Cantilevered beam
RE: Corbel or Cantilevered beam
There is a big difference between the results from beam theory and strut/tie for what is defined as a Deep Beam. As this fits the dimensions of a Deep beam according to most codes, I do not think that you should be making the recommendation that you have.
RE: Corbel or Cantilevered beam
RE: Corbel or Cantilevered beam
Once again: Strut and tie. I would love for anyone to give me a good reason to approach this differently. Always happy to learn, but pretty sure I'm right on this one.
Regards,
YS
B.Eng (Carleton)
Working in New Zealand, thinking of my snow covered home...
RE: Corbel or Cantilevered beam
Prior to strut-tie method, the ACI left the deep beam design largely in the hands of the engineers, except some provisions for shears. Lack of specific method, for bending, the use of conventional flexural method was widely spread, including me, though we knew well the beam theory really does not apply. Ever since the advance in computer software, I used to double check the design against computer model, to predict, or to match the stresses distribution generated.
I learned strut-tie method by self-learning while working on a Canadian project. I have never mastered it, but I appreciate its clear concept, and allowrance for creative thinking.
With one leg in each camp, I wouldn't reject either one in dealing with deep beams. But at times, one could be clearly superior than the other. The choice, again, purely depends on the anticipate member behaviors, and loading conditions. This is my ultimate opinion on this matter.