Blog

A wall footing has the following conditions. Determine the moment capacity, Mn, of the footing. Assume the footing is 3 ft wide, the pressure that acts on the bottom of the footing is 6,533 psf, and the reinforcement is a #5 bar spaced every 12 inches.The bottom of the footing is at a depth of 4 ft below grade.The service dead load is 7 kips/ft, and the service live load is 7 kips/ft.The wall is 10 in. thick.The footing is 16 in. thick.The allowable soil pressure, qa, is 5,700 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 = 3,400 psi and fy = 60,000 psi.

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

Although concrete is made up of essentially elastic, brittle materials, its stress-strain curve is nonlinear and it appears to be somewhat _______.

There is a permanent reduction in strength when concrete is exposed to sustained high loads.

Concrete subjected to a temporary axial load greater than the critical load will eventually fail under loads less than the critical load.

A wall footing has the following conditions. Determine the critical one-way shear, Vu, at a distance of d from the face of the wall. Assume the footing is 5 ft wide, the pressure that acts on the bottom of the footing is 5,680 psf, and the reinforcement is a #7 bar spaced every 12 inches.The bottom of the footing is at a depth of 2 ft below grade.The service dead load is 13 kips/ft, and the service live load is 8 kips/ft.The wall is 10 in. thick.The footing is 12 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.

A wall footing has the following conditions. Determine the shear capacity, φVn, of the footing. Assume the footing is 4 ft wide, the pressure that acts on the bottom of the footing is 5,500 psf, and the reinforcement is a #6 bar spaced every 12 inches.The bottom of the footing is at a depth of 2 ft below grade.The service dead load is 9 kips/ft, and the service live load is 7 kips/ft.The wall is 16 in. thick.The footing is 15 in. thick.The allowable soil pressure, qa, is 4,400 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 = 4,000 psi and fy = 60,000 psi.

A group of 30 tests on a given type of concrete had a mean strength of 4,000 psi and a standard deviation of 600 psi. Does this concrete satisfy the strength requirement for 3,000 psi concrete?

A concrete block will eventually break if a constant load is applied at 75% to 80% of its ultimate compressive strength due to _______.

The concrete in the core of a spiral column is subjected to a uniform confining stress σ3 of 220 psi. What will the compressive strength σ1 be? The unconfined uniaxial compressive strength is 4,700 psi.