A rectangular footing is to support two square columns each 12” x 12” and spaced 12 feet on centers. One column carries a load of 40 kips and the other carries a load of 50 kips. The footing is 2 ft thick and its length should extend beyond the center of the column carrying the 40-kip load. The base of the footing is 5 ft below the ground surface. Assume specific gravity og concrete and soil above the footing to be 2.4 and 1.78, respectively. Determine the length of the footing if the allowable soil bearing capacity is 2000 psf.
Answer: L = 18.34 feet