Three-dimensional finite element analyses of reinforced concrete columns.

A recently developed three-dimensional concrete law is used for the analysis of concrete specimens and reinforced concrete columns subjected to different load patterns. The hypoelastic, orthotropic concrete constitutive model includes coupling between the deviatoric and volumetric stresses, works with both proportional and non-proportional loads and is implemented as a strain driven module. The finite element (FE) implementation is based on the smeared crack approach with rotating cracks parallel to the principal strain directions. The concrete model is validated through correlation studies with: (a) experimental tests on concrete cylinders confined by different mechanisms, including steel and fiber reinforced polymer jackets; (b) experimental results on three reinforced concrete columns tested at the University of California, San Diego. The correlations are overall very good, and the FE responses capture all the main phenomena observed in the experimental tests.