Soil borings indicate that a building site is underlain by clean, fine to coarse sand. The following standard penetration test information is obtained from a boring log: At 2-ft depth, N is 12; at...

Soil borings indicate that a building site is underlain by clean, fine to coarse sand. The following standard penetration test information is obtained from a boring log: At 2-ft depth, N is 12; at 6-ft depth, N is 14; at 10-ft depth, N is 18; at 14-ft depth, N is 20; at 20-ft depth, N is 25; at 25-ft depth, N is 26. These N values refer to N₆₀. No groundwater was encountered. It is planned to construct a square footing 4 ft deep to carry a 300-kip column load near to this boring location. If a 1-in. settlement is tolerable, what size foundation should be provided? What size footing should be provided if the groundwater table could rise to footing level? (Refer to Figures 12 and 13; assume D_R
is 60 pct.)