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The minimum number of longitudinal bars in a rectangular column is four.

To account for the effect of accidental moments, the ACI Code specifies that the maximum load on a column must not exceed 0.85 times the axial-load capacity of tied columns and 0.8 times the axial-load capacity of spiral columns.

A common example of a column that supports axial forces and bending about two perpendicular axes is a(n) _______.

A wall footing has the following conditions. Determine the required development length, ld, for the reinforcement. Assume the footing is 3 ft wide, the pressure that acts on the bottom of the footing is 7,333 psf, and the reinforcement is a #8 bar spaced every 12 inches.The bottom of the footing is at a depth of 5 ft below grade.The service dead load is 9 kips/ft, and the service live load is 7 kips/ft.The wall is 12 in. thick.The footing is 15 in. thick.The allowable soil pressure, qa, is 6,000 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 = 3,300 psi and fy = 60,000 psi.

A wall footing has the following conditions. Determine the required cross-sectional area of shrinkage and temperature reinforcement. Assume the footing is 5 ft wide, the pressure that acts on the bottom of the footing is 5,920 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 8 kips/ft.The wall is 10 in. thick.The footing is 14 in. thick.The allowable soil pressure, qa, is 5,400 psf.The soil has a density of 110 lb/ft3.The concrete has a density of 150 lb/ft3.The concrete cover has a thickness of 3 in.f’c = 3,700 psi and fy = 60,000 psi.

A wall footing has the following conditions. Determine the pressure that acts on the bottom of the footing. Assume the footing is 4 ft wide.The bottom of the footing is at a depth of 3 ft below grade.The service dead load is 11.8 kips/ft, and the service live load is 6.1 kips/ft.The wall is 16 in. thick.The footing is 15 in. thick.The allowable soil pressure, qa, is 5,900 psf.The soil has a density of 110 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 distance to the neutral axis, c, measured from the top of the footing. Assume the footing is 4 ft wide, the pressure that acts on the bottom of the footing is 4,599 psf, and the reinforcement is a #6 bar spaced every 12 inches.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 7 kips/ft.The wall is 16 in. thick.The footing is 16 in. thick.The allowable soil pressure, qa, is 4,200 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 wall footing has the following conditions. Determine the required development length, ld, for the reinforcement. Assume the footing is 6 ft wide, the pressure that acts on the bottom of the footing is 4,733 psf, and the reinforcement is a #8 bar spaced every 12 inches.The bottom of the footing is at a depth of 4 ft below grade.The service dead load is 13 kips/ft, and the service live load is 8 kips/ft.The wall is 12 in. thick.The footing is 11 in. thick.The allowable soil pressure, qa, is 4,000 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 = 3,900 psi and fy = 60,000 psi.

Use the interaction diagrams found in Appendix A of the textbook to determine whether the following circular spiral column can safely support a load of Pu = 254 kip and Mu = 229.0 kip-ft.h = 18 in.fc’ = 4 ksify = 60 ksiγ = 0.9ρg = 0.01

A wall footing has the following conditions. Determine the critical bending moment, Mu, at the face of the wall. Assume the footing is 5 ft wide and the pressure that acts on the bottom of the footing is 4,880 psf.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 7 kips/ft.The wall is 10 in. thick.The footing is 11 in. thick.The allowable soil pressure, qa, is 4,600 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 = 3,400 psi and fy = 60,000 psi.