Design a square interior column footing for a 15-in. square tied
interior column that supports a dead load of 160 kips and live load
of 180 kips. The column is reinforced with eight # 8 bars, also,
the base of the footing is 6 ft below the grade line, the soil
weight is 100 lb/ft3, the concrete weight is 150 lb/ft3, f’c =
4,000 psi, fy = 60,000 psi and qa = 4 kip/ft2.