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In a typical construction cycle, the reinforcement and concrete for the columns are placed after the reinforcement and concrete for the beams and slabs in a floor system above it.

In tall buildings, higher strength concrete is generally used in the columns to reduce their size.

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.

Strength limit states deal with collapse of the structure, whereas serviceability limit states deal with disruption of the use of the structure but not collapse.

Determine the maximum axial strength φPn,max for the following tied column.Column width, b = 20 in.Column thickness, h = 24 in.Number of longitudinal bars = 4Size of longitudinal bars = No. 8Size of ties = No. 4Concrete strength = 7,000 psiYield strength of longitudinal bars = 60,000 psiYield strength of ties = 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 = 24 in.Column thickness, h = 14 in.Clear cover to ties = 1.5 in.Number of longitudinal bars = 10Size of longitudinal bars = No. 10Size of ties = No. 3Concrete strength = 8,000 psiYield strength of longitudinal bars = 60,000 psiYield strength of ties = 40,000 psi

A rectangular beam has a cross section of b = 18 in., h = 22 in., and d = 19.5 in. It is reinforced with three No. 7 Grade 60 bars. The concrete strength is 8,800 psi (normal weight). The beam has Grade 60 No. 3 stirrups. Determine the modulus of rupture of the concrete, fr.

Tied columns are more ductile than spiral columns, giving tied columns a higher strength-reduction factor.

If additional steel reinforcement in a column prevents concrete from expanding outward under compression, then logically it follows that _______.

Over _____ percent of all columns in buildings in nonseismic regions are tied columns.