Check for transfer forces at column base (pad and strip base:ACI 318)
This check applies when a concrete column is attached to the foundation.
Determinate the bearing strength of the column:
Φ*Pnb,c = Φbearing (0.85*f’c * Ac)
If
Φ*Pnb,c < - Pu
Then check fails
Else determinate the bearing strength of the footing:
Φ*Pnb,f = min [√(A2/Ac), 2] * Φbearing (0.85*f’c * Ac)
where for rectangular columns:
A2 = min {Lx , 2tftg + lx+ min [(Lx-lx)/2 - abs(ex), 2tftg]} * min {Ly , 2tftg + ly + min [(Ly-ly)/2 - abs(ey), 2tftg]}
Circular columns are treated as square members with the same area.
If
Φ*Pnb,f < - Pu
Then check fails
Required min. area of dowel bars between column and footing is then:1
As,min = 0.005*Ac
Currently dowel bars are not designed.
The area of the provided column reinforcement As,prov,column is the same as the provided reinforcement of starter/dowel bars.
If
As,min > As,prov,column
Then check fails
Footnotes