When designing columns, it is often more desirable to use symmetrical reinforcement.

Reinforced concrete is elastic and has a compressive strength that is much higher than its tensile strength.

Determine the required splice length for the epoxy-coated longitudinal bars in the following tied column made of normal-weight concrete. Assume that some of the longitudinal bars are in tension and that the connection should be designed as a Class B contact lap splice. Use ACI 318-14 Table 25.4.2.2 to calculate the development length, and assume that the ties satisfy the Code minimum.Column width, b = 26 in.Column thickness, h = 24 in.Clear cover to ties = 1.5 in.Number of longitudinal bars = 14Size of longitudinal bars = No. 10Size of ties = No. 3Concrete strength = 7,000 psiYield strength of longitudinal bars = 60,000 psiYield strength of ties = 40,000 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 = 28 in.Column thickness, h = 12 in.Clear cover to ties = 1.5 in.Number of longitudinal bars = 14Size of longitudinal bars = No. 9Size of ties = No. 3Concrete strength = 5,500 psiYield strength of longitudinal bars = 60,000 psiYield strength of ties = 40,000 psi

Determine the maximum axial strength φPn,max for the following circular spiral column.Column diameter, h = 18 in.Number of longitudinal bars = 10Size of longitudinal bars = No. 8Size of spirals = No. 3Concrete strength = 3,500 psiYield strength of longitudinal bars = 60,000 psiYield strength of spirals = 60,000 psi

Tied columns cannot be L-shaped.

Determine the maximum axial strength φPn,max for the following tied column.Column width, b = 26 in.Column thickness, h = 12 in.Number of longitudinal bars = 4Size of longitudinal bars = No. 10Size of ties = No. 4Concrete strength = 7,500 psiYield strength of longitudinal bars = 60,000 psiYield strength of ties = 40,000 psi

Ties serve as shear reinforcement for columns.

Because the designer has little control over the arrangement of the bars in a circular column, the interaction diagram should be computed for the least favorable bar orientation.

Determine the maximum pitch, s, for the spirals in the following circular column.Column diameter, h = 26 in.Clear cover to spirals = 1.5 in.Number of longitudinal bars = 6Size of longitudinal bars = No. 8Size of spiral = No. 3Concrete strength = 3,000 psiYield strength of longitudinal bars = 60,000 psiYield strength of spiral = 60,000 psi