Performance analysis and design of circular high-strength concrete-filled double-skin aluminum tubular short columns under axial loading

This study investigates the performance and design of high-strength circular concrete-filled double-skin aluminum tubular (CFDAT) columns under axial loading. A new fiber element (FBE) model incorporating a new lateral confinement model is developed that considers the confinement effects and material nonlinearities. A new strength degradation factor is proposed for determining the postpeak behavior of the confined concrete in CFDAT circular columns. Existing experimental results are used to validate the accuracy of the predicted ultimate strength and axial load-strain (P-e$$ P-\varepsilon $$) curves of CFDAT columns under axial loading. A comparison of the predictions of the ultimate strength and P-e$$ P-\varepsilon $$ curves of CFDAT columns using the proposed lateral confinement model is made against the prediction using the three-dimensional finite element modeling and the existing lateral pressure model of CFDAT columns proposed by other researchers. The performance of the CFDAT columns under axial loading is investigated using a detailed parametric study. The accuracy of existing empirical formulas given in various design standards for conventional concrete-filled steel tubular columns as well as given by another researcher in predicting the ultimate strength of CFDAT columns is examined. Finally, a simple design formula is proposed and validated against the experimental and numerical results obtained from this study. It is found that the proposed FBE model and the simplified model developed in this study can accurately predict the performance of CFDAT columns under axial loading.