Tension Cracking in Columns Under Compression Loads

Abstract

Cracking occurs in reinforced concrete members when principal tension stresses exceed the tensile strength of the concrete. This paper examines five types of cracking in concrete columns under compressive axial load caused by creep and shrinkage, by the cement heat of hydration, by ambient temperature changes and by unloading. Following types of cracks are considered: unloading cracks; cracks in thick columns under light loads; cracks in heavily reinforced columns; cracks from heat of hydration; and cracks from imposed displacements. The paper describes the causes of cracks, analyzes them and provides photos of cracked columns. Also provided are design and construction recommendations to prevent or reduce these cracks.