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]} |
Note:
IfCircular columns are treated as square members with the same area.
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 |
1 ACI 318-08 Section 15.8.2.1