ACI-318 Shear link spacing

[nglclrk]

I am designing a member where the shear stress ?Vc ? Vu ? 0.5?Vc, thus requiring me to provide shear links.

Equ 11-13 (Av,min = 0.75*fc^.5*(bw*s)/fyt) includes the term, s (link spacing). My question is...am I expected to use (or calculate) a particular value for s (s = d/2 for instance)? Or can I choose any reasonable value for s knowing that Av,min is directly proportional to the value of s?

Thanks

 

[JAE]

A better way to look at this is to re-arrange the formula to give you a value of Av/s.

This is the area of shear reinforcing required in a distance "s".

 

[nglclrk]

Thanks JAE. I hadn't thought of adopting that approach for the minimum shear reinforcement but I see that the code commentary does something similar to what you suggested down beside equ 11-15 when designing rebar for excess shear.