ABSTRACT
This chapter deals with the design of reinforced concrete columns subjected to concentric or axial ultimate loads without bending. Analytical principles are used that are similar to those employed when designing sections to resist bending with or without direct force. The minimum dimension of a column depends, among other factors, on the period of fire resistance required. A minimum cross-sectional area of not less than 0.4% of longitudinal reinforcement should normally be provided in a column. However, where the concrete section provided is of such a size that the ultimate load may be resisted by the concrete alone, the section may be designed as a plain concrete column. Pure axial load is extremely rare and expression is normally only used in the design procedures for slender columns and columns subjected to biaxial bending. The imposed loads on the roof and upper floors are the same as are assumed for the beams and slabs.
