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Spiral reinforcement acts to restrain the lateral expansion of the column core under high axial loads and delays the failure of the core, making the column more ductile.

To minimize splice lengths, choose the smallest practical bar size and the lowest practical concrete strength.

Determine the required splice length for the uncoated 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 = 22 in.Column thickness, h = 26 in.Clear cover to ties = 1.5 in.Number of longitudinal bars = 4Size of longitudinal bars = No. 10Size of ties = No. 3Concrete strength = 3,500 psiYield strength of longitudinal bars = 60,000 psiYield strength of ties = 40,000 psi

Use the interaction diagrams found in Appendix A of the textbook to determine whether the following rectangular tied column with bars in 2 faces can safely support a load of Pu = 1,320 kip and Mu = 645.3 kip-ft.b = 20 in.h = 22 in.fc’ = 4 ksify = 60 ksiγ = 0.6ρg = 0.03

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

Determine the maximum axial strength φPn,max for the following circular tie column.Column diameter, h = 26 in.Number of longitudinal bars = 9Size of longitudinal bars = No. 8Size of ties = No. 4Concrete strength = 6,000 psiYield strength of longitudinal bars = 60,000 psiYield strength of ties = 60,000 psi

In tall buildings, the concrete strength in the columns is often _______ than in the floors because _______.

The interaction diagram for a biaxially loaded column will be a two-dimensional interaction surface.

Which of the follow is not a reason ties are provided in reinforced concrete columns?

Misalignment of a load on a column will produce a moment.