Analytical behavior of concrete-filled aluminum tubular stub columns under axial compression

This paper presents finite element investigations on the structural behaviors of circular concrete-filled aluminum tubular (CFAT) stub columns under axial compression. The finite element models are developed by considering the nonlinearities of concrete and aluminum materials and the interactions between the two components. The predicted ultimate strengths, load-axial strain relationships and failure modes are compared to those from collected experimental data. Full range analysis on the load-deformation N-epsilon are conducted, where the investigations on the multi-axial stress conditions of the aluminum tube and the interaction stress between the aluminum tube and concrete core are included. The verified finite element models are used to carry out a series of parametric studies on key material and geometric properties. The ductility index DI and strain at ultimate strength epsilon(scy) are studied. Equations to determine epsilon(scy) for circular CFAT stub columns are proposed. The applicability of the existing design method for CFST to CFAT stub columns is investigated.