LAUSR

Abstract Concrete compressive strength and ductility are strongly affected by the level of confinement and significantly improve with its magnitude. In concrete columns such enhancement can be achieved by properly designed transverse reinforcement. The behavior under axial loading can be accurately described by numerous models from the literature or more conservatively using the design codes; however, their applicability is rather limited to the most common reinforcement layouts and very often to monotonous axial compression. This deficiency can be eliminated by incorporating nonlinear finite element simulations, which allow for arbitrary loading configuration and topology, into the design process. In this paper an advanced constitutive model Concrete Damage-Plastic Model (CDPM 2) by Grassl and coworkers is thoroughly compared against the experimental data from the literature on confined concrete. Subsequently, based on numerical simulations of axially compressed circular columns with various alternatives of reinforcement it is shown that the results are inconsistent with the generally accepted assumptions incorporated into the design codes in the case of spiral reinforcement but perfectly match when the circular hoops are used.