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# Civil Engineering/Why use Normal stress formula to calculate Shear stress in bolts ?

Question
Say a bolt is used is used to join 2 plates, Shear stress is Force/ bolt area.
Shear stress = P/A
This formula looks like NORMAL stress , isn't it ?
What is the stress distribution in bolts ?

But there is also shear stress = V Q /I b
Why not use the above formula to calculate shear stress in bolts ?
I am confused ?
Thanks.

Dear Ben

You know that VQ/IB is the shear stress related to moment distribution along the member span ( see popov )  then it is not suitable for a direct shear application like in a bolt.  in addition a plastic redistribution of stresses make the V/A formula suitable indeed with a carefully adopted margin of safety.

Regards
BEH

Civil Engineering

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