Finite element analysis of the Circular Double Skin Tubular Concrete (DSTC) under concentric loading

Abstract

This paper presents a numerical investigation on the behaviour of circular double-skin tubular concrete (DSTC) under concentric loading. The numerical analysis is carried out using a three-dimensional non-linear finite element package (3D-NLFEA). In DSTC specimen, the concrete is enclosed by FRP wraps at the outer tube and circular hollow steel (CHS) at the inner tube. The concrete constitutive model is based on the authors developed plasticity-fracture model which uses a non-constant plastic dilation rate for modelling concrete dilation under compression. The nonlinear buckling analysis is included in the analysis. Random material imperfection is used to induced asymmetric failure pattern. Mohr-Coulomb friction model is used to simulate the contact behaviour between concrete and CHS elements. The results from the FEA are compared with the available experimental results. From the comparison, it can be concluded that the use of the authors plasticity-fracture model is in good agreement with the test results.