Finite element modeling of confined concrete-II: Plastic-damage model

This paper presents a modified plastic-damage model within the theoretical framework of the Concrete Damaged Plasticity Model (CDPM) in ABAQUS for the modeling of confined concrete under non-uniform confinement. The modifications proposed for the CDPM include a damage parameter, a strain-hardening/softening rule and a flow rule, all of which are confinement-dependent, and a pressure-dependent yield criterion. The distinct characteristics of non-uniformly confined concrete are also included in this model by defining an effective confining pressure. Finite element models incorporating the proposed CDPM model were developed for concrete in a number of confinement scenarios, including active confinement, biaxial compression, FRP-confined circular and square columns, and hybrid FRP-concrete-steel double-skin tubular columns. The finite element predictions are shown to be in close agreement with the existing test results. The limitations of the proposed model are also discussed towards the end of the paper, pointing to future research needs in this area.