Simplified Design for Footings - Simplified Design of Reinforced Concrete Buildings - page 233

For f c = 4000 psi:

P u 512

96.7 +

( )

h = 4.15c

A f +

2in. = 4.15 4.25 2 = 40.6 + 2 = 42.6in.

Bearing on column:
Allowable bearing load = 0.85 φ f c A g , φ = 0.55 ACI 318, Section 22.5.5

= 0.85 0.55 4 16 2 = 479 kips < P u 501 kips

The excess compression must be transferred to the footing by reinforcement consisting of extended column
bars or dowels (calculations not show).

Figure 7-11 illustrates the footing for this case.

4-#8 column bars

4-#6 dowels x 4'-0"

9'-6" square

Figure 7-11 Plain Concrete Footing for Interior Column of Building No. 2 (Non-sway Frame)

References

7.1 Notes on ACI 318-08 , Chapter 7, Design for Flexure, 10th Edition, EB708, Portland Cement Association,
Skokie, Illinois, 2008.

7.2 Building Code Requirements for Structural Concrete ACI 318-11 and Commentary , American Concrete
Institute, Farmington Hills, Michigan, 2011.