Effects of load-related parameters on the response of concrete-filled double-skin steel tube columns subjected to lateral impact

Concrete-filled double-skin steel tubes (CFDSTs), which consist of two concentric steel tubes with concrete sandwiched between them, have found increasing use as a new sustainable alternative to existing structural bridge piers and building columns, over the recent years. They can hence become vulnerable to lateral impact loads such as those from collision of vehicles, vessels, barges or flying debris from a nearby explosion. This paper treats the response of such columns under a combination of static axial and dynamic lateral impact loads using a fully coupled numerical analysis with the finite element code LS-DYNA. The capability of the numerical model to trace the response and to predict the failure modes of the columns has been validated using extensive results from experiments carried out recently at Queensland university of Technology. A parametric sensitivity analysis is conducted to investigate the effects of several load-related parameters on the key response of the CFDST columns. Results provide new information on the impact response of CFDST columns and the effects of controlling parameters to form an extensive database. This can be employed to develop appropriate equations and design calculation methods for CFDST columns under lateral impact loading.