Three-dimensional finite element analysis of the cyclic response of RC columns

This paper presents three-dimensional finite element models for the accurate response simulation of RC columns subjected to severe cyclic loading. The models integrate advanced constitutive models for concrete, steel reinforcement, and bond-slip behaviour of bars. Concrete is modelled with a triaxial constitutive capable of simulating material degradation due to cracking and crushing, crack opening and closing behaviour, and the increase of strength and ductility under multiaxial compression conditions. The cyclic response of steel reinforcement is modelled with a Menegotto-Pinto law modified to account for the low-cycle fatigue of bars using an energy criterion. The bond-slip behaviour of longitudinal bars is modelled using a concrete-steel interface element previously proposed by one of the authors of this paper. The interface element has a bond stress-slip constitutive law that predicts bond deterioration caused by bar slip, cyclic loading and tensile yielding of steel. The finite element models predict well the damage mechanisms and force-displacement responses of cantilever columns tested under fully-reversed lateral cyclic loading.