Spiral columns have a strength-reduction factor, φ, of _____, while tied columns have a value of _____.

A common example of a column supporting axial forces and bending about one axis is a corner column in a frame.

Tied columns have higher ductility giving less warning before a failure.

The strength-reduction factor of a compression-controlled tied column is 0.65, while a spiral column is _____.

Compute the axial compressive strength Pn and moment capacity Mn of the following tied column when the largest strain in the concrete is 0.003 and the strain in the tension reinforcement is 0.003. Note that you should not include φ in the answer and that you should not consider Pn,max.b = 12 in.h = 20 in.Clear cover to ties = 1.5 in.Number of longitudinal bars = 6Size of longitudinal bars = No. 9Size of ties = No. 3Concrete strength = 3,500 psiYield strength of longitudinal bars = 60,000 psiYield strength of ties = 60,000 psi

A wall footing has the following conditions. Determine the pressure that acts on the soil. Assume the footing is 5 ft wide.The bottom of the footing is at a depth of 3 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 15 in. thick.The allowable soil pressure, qa, is 4,700 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 = 3,200 psi and fy = 60,000 psi.

Determine the required splice length for the longitudinal bars in the following tied column. Assume that all of the longitudinal bars are in compression and that you will use a contact lap splice. Do not incorporate a reduction in length due to ACI 318-14 Section 10.7.5.2.1.Column width, b = 26 in.Column thickness, h = 28 in.Clear cover to ties = 1.5 in.Number of longitudinal bars = 12Size of longitudinal bars = No. 10Size of ties = No. 4Concrete strength = 4,500 psiYield strength of longitudinal bars = 60,000 psiYield strength of ties = 40,000 psi

Compression members in concrete structures are commonly subjected to moments in addition to axial loads.

Determine the maximum axial strength φPn,max for the following circular spiral column.Column diameter, h = 22 in.Number of longitudinal bars = 10Size of longitudinal bars = No. 6Size of spirals = No. 4Concrete strength = 5,500 psiYield strength of longitudinal bars = 60,000 psiYield strength of spirals = 60,000 psi

Determine the maximum axial strength φPn,max for the following circular spiral column.Column diameter, h = 24 in.Number of longitudinal bars = 12Size of longitudinal bars = No. 10Size of spirals = No. 4Concrete strength = 9,000 psiYield strength of longitudinal bars = 60,000 psiYield strength of spirals = 60,000 psi