A wall footing has the following conditions. Determine how much greater the factored load is than the unfactored load.The bottom of the footing is at a depth of 3 ft below grade.The service dead load is 10.3 kips/ft, and the service live load is 6.5 kips/ft.The wall is 12 in. thick.The footing is 13 in. thick.The allowable soil pressure, qa, is 4,900 psf.The soil has a density of 120 lb/ft3.The concrete has a density of 150 lb/ft3.The concrete cover has a thickness of 3 in.f’c = 4,000 psi and fy = 60,000 psi.

In fcr = f’c + 2.33s – 500, what does the s represent?

The concrete containing Type I cement in a structure is cured for 5 days at 70°F, followed by 3 days at 72°F. Use the maturity concept to estimate its strength as a percentage of the 28-day strength under standard curing. Maturity is defined as M = Σ(Ti + 50)(ti) where Ti is in degrees F and ti is in days.

A wall footing has the following conditions. Determine the required development length, ld, for the reinforcement. Assume the footing is 5 ft wide, the pressure that acts on the bottom of the footing is 5,200 psf, and the reinforcement is a #9 bar spaced every 12 inches.The bottom of the footing is at a depth of 2 ft below grade.The service dead load is 11 kips/ft, and the service live load is 8 kips/ft.The wall is 10 in. thick.The footing is 13 in. thick.The allowable soil pressure, qa, is 4,400 psf.The soil has a density of 125 lb/ft3.The concrete has a density of 150 lb/ft3.The concrete cover has a thickness of 3 in.f’c = 3,000 psi and fy = 60,000 psi.

A wall footing has the following conditions. Determine the moment capacity, Mn, of the footing. Assume the footing is 4 ft wide, the pressure that acts on the bottom of the footing is 4,800 psf, and the reinforcement is a #7 bar spaced every 12 inches.The bottom of the footing is at a depth of 5 ft below grade.The service dead load is 8 kips/ft, and the service live load is 6 kips/ft.The wall is 10 in. thick.The footing is 15 in. thick.The allowable soil pressure, qa, is 5,100 psf.The soil has a density of 125 lb/ft3.The concrete has a density of 150 lb/ft3.The concrete cover has a thickness of 3 in.f’c = 3,300 psi and fy = 60,000 psi.

Subfreezing temperatures can significantly decrease the compressive and tensile strengths of moist concrete.

A wall footing has the following conditions. Determine the depth, d, of the reinforcement. Assume the footing is 5 ft wide, the pressure that acts on the bottom of the footing is 5,280 psf, and the reinforcement is a #4 bar spaced every 12 inches.The bottom of the footing is at a depth of 5 ft below grade.The service dead load is 14 kips/ft, and the service live load is 6 kips/ft.The wall is 14 in. thick.The footing is 12 in. thick.The allowable soil pressure, qa, is 5,000 psf.The soil has a density of 125 lb/ft3.The concrete has a density of 150 lb/ft3.The concrete cover has a thickness of 3 in.f’c = 3,100 psi and fy = 60,000 psi.

A group of 20 tests on a given type of concrete had a mean strength of 4,000 psi and a standard deviation of 800 psi. Does this concrete satisfy the strength requirement for 5,000 psi concrete?

Other strength parameters are expressed relative to the compressive strength.

A wall footing has the following conditions. Determine the minimum width of the footing.The bottom of the footing is at a depth of 5 ft below grade.The service dead load is 6 kips/ft, and the service live load is 6 kips/ft.The wall is 12 in. thick.The footing is 16 in. thick.The allowable soil pressure, qa, is 4,100 psf.The soil has a density of 115 lb/ft3.The concrete has a density of 150 lb/ft3.The concrete cover has a thickness of 3 in.f’c = 3,200 psi and fy = 60,000 psi.