Title: Deform Ability of Reinforced Concrete Columns
Author(s): Murat Saatcioglu
Publication: Symposium Paper
Appears on pages(s): 421-452
Keywords: columns (supports); confined concrete; deformation; ductility; earthquake-resistant structures; elastic properties; reinforced concrete; structural design; tests; Structural Research
Deformation capacity of reinforced concrete columns is investigated by examining the available test data. Tests of square columns, conducted under constant axial load and lateral displacement reversals, as well as those conducted under concentric compression, are considered. The test data are evaluated in terms of ductility and drift ratios. The results indicate that high axial compression, and high shear stress reversals, as well as high rates of loading, reduce column deformability. Confinement of core concrete improves column deformability significantly. This is achieved through the use of closely spaced transverse and longitudinal reinforcement, where the longitudinal reinforcement is laterally supported by closed hoops and crossties. The confinement action also improves with the volumetric ratio and yield strength of transverse reinforcement. The ACI 318-89 requirements for the amount of confinement reinforcement appear to be adequate for the columns evaluated in this paper.