Impact performance of assembled aluminum alloy-concrete-carbon steel double-skin tubular column

To improve the assembly and corrosion resistance of jacket legs in offshore platforms, a novel assembled aluminum alloy-concrete-carbon steel double-skin tubular column was proposed. This study investigated the impact performance of the assembled column using the independently developed pendulum impact system. Four specimens, including three assembled columns and one non-assembled column, were designed and tested. The failure modes, impact force and displacement time history curves, and strain response were analyzed. The results showed that the failure modes of both non-assembled and assembled columns exhibited the characteristics of global bending coupled with local deformation. The impact performance of the assembled column was superior to that of the non-assembled column. Subsequently, a parametric study was conducted using the validated finite element (FE) model. The impact velocity had a significant influence on the impact performance of the assembled column, whereas the effect of the 0.2 % proof stress of aluminum alloy and thickness of sleeve were also non-negligible. In contrast, the influence of concrete strength and pretension of high-strength bolts was minor. Finally, the applicability of the current design models to the assembled columns was assessed. The current design models provided the conservative estimates for the impact bearing capacity of the assembled columns.