Shear strength of rebar

[Engingguy]

Hello folks,
I generally use a shear strength of 0.6 Fy for rebar, but I can't find the reference in ACI 318-14 for a shear factor. I have seen values from 0.5 to 0.75 Fy used,so my 0.6 seems a safe middle value, but for the life of me can find no reference to where that comes from. Can anyone steer me to a code that says what value(s) to use?
Thanks

 

[Guest262653]

Your numbers are correct. I'm not familiar with ACI 318-14 but the shear yield stress in pure shear is usually calculated using the von Mises yield criterion, which establishes that it is equal to fy/sqrt(3)=0.577fy.

 

[JAE]

Look here for a similar discussion.
thread507-165911
Note that the 0.6Fy is not an "allowable" shear but a point of yield. Thus you still need a safety factor on it.



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[hokie66]

The shear strength of rebar is not a factor in concrete design. The bearing or crushing of the concrete in dowel action always controls. This is probably the reason codes don't define the shear strength of the bars themselves.

 

[Lomarandil]

It's rare for structural engineers, but sometimes the rebar isn't (yet) embedded in concrete.

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