A commercial building is being constructed with spread footings. The soil bearing capacity is determined to be 2000 psf. The building has a total dead load of 150 psf and a live load of 50 psf. What is the minimum size required for the spread footings?
- A12x12 inches
- 16x16 inches
- C20x20 inches
- D24x24 inches
Exam tip
Always consider the total load and soil bearing capacity when determining the size of footings.
Why B is correct
The total load on the footing is the sum of the dead load and live load, which is 150 psf + 50 psf = 200 psf. Since the soil bearing capacity is 2000 psf, the minimum size of the footing can be calculated by dividing the total load by the bearing capacity, which is 200 psf / 2000 psf = 0.1. The smallest option that meets this requirement is 16x16 inches.