J8Column bases and bearing on concrete

Provisions shall be made to transfer the column loads and moments to the footings and foundations.

In the absence of code regulations, the design bearing strength, $\phi_{c} P_{p}$, and the allowable bearing strength, $P_{p} / \Omega_{c}$, for the limit state of concrete crushing are permitted to be taken as follows:

$\phi_{c}=0.65$ (LRFD) $\quad \Omega_{c}=2.31$ (ASD)

The nominal bearing strength, $P_p$, is determined as follows: (a) On the full area of a concrete support $P_p=0.85f_c^{\prime}A_1$ (J8-1) (b) On less than the full area of a concrete support $P_p=0.85f_c^{\prime}A_1\sqrt{A_2/A_1}\leq1.7f_c^{\prime}A_1$ (J8-2)

where