ACI 318 Eq. 17.4.3.4 2

[Simba13]

So I just finished an analysis of some anchor bolts for a cleat on a concrete dock. Went through all of the checks from chapter 17 in 318-14 and I was curious about Eq. 17.4.3.4 for the tension pullout case. The equation is Np= 8*(Abrg)*f'c. Does anyone know the exact origin of the 8 factor? The commentary states "corresponds to the load at which crushing of the concrete occurs due to bearing..." But that leaves a bit to be desired.

Any clues?

Thanks.

 

[Agent666]

The NZ standard which is based on ACI provisions, references the fib bulletin 216 for the basis of the equation you note.

This is what they had to say in the reference:-

So based on testing and downrating the 12-15 f'c they note.