concrete column[′käŋ‚krēt ′käl·əm]
A structural member subjected principally to compressive stresses. Concrete columns may be unreinforced, or they may be reinforced with longitudinal bars and ties (tied columns) or with longitudinal bars and spiral steel (spiral-reinforced columns). Sometimes the columns may be a composite of structural steel of cast iron and concrete.
Unreinforced concrete columns are seldom used because of transverse tensile stresses and the possibility of longitudinal tensile stresses being induced by buckling or unanticipated bending. Because concrete is weak in tension, such stresses are generally avoided. When plain concrete columns are used, they usually are limited in height to five or six times the least thickness. Under axial loading, the load divided by the cross-sectional area of the concrete should not exceed the allowable unit compressive stress for the concrete. See Concrete, Reinforced concrete