Structural behaviour of high-strength rectangular concrete-filled steel hollow section columns

Abstract

This thesis presents an experimental and analytical investigation of the non-linear behaviour and design of high-strength rectangular concrete-filled steel hollow section (CFSHS) columns under axial loading, pure bending and eccentric loading. In the experimental programme, 117 specimens were tested to examine the effects of material strength, slenderness and aspect ratio on the behaviour of the columns. Ductility performance of the high-strength concrete was found to be significantly enhanced by the steel hollow section. Analytical models are developed for estimating the behaviour of high-strength rectangular CFSHS columns. The calibration of the models shows that they agree reasonably well with the present experimental results as well as those previously reported by other researchers. The experimental results are also employed to calibrate the specifications in the design codes, i.e. EC4, ACI and AISC. It indicates that modifications should be incorporated into the codes so that a safe and accurate design can be achieved for high-strength rectangular CFSHS columns. Based on the experimental and analytical investigation, design guidelines are developed and presented.