Experimental research on load separation of concrete-filled circular steel tube short columns

Abstract

In recent years, scholars from various countries have conducted extensive experiments and analytical studies on the axial compressive behavior of circular concrete-filled steel tube (CFST) columns. However, the existing research has been based on overall loading analysis of circular CFST columns, making it difficult to accurately measure the loads borne by the steel tube and the core concrete separately. In order to better study the axial compressive behavior of circular CFST columns, this paper adopts the load separation device proposed by Hong-Song Hu and prepares 16 specimens with different concrete strengths for axial compression tests, directly measuring the load components of circular CFST columns under axial compression. The feasibility of the superposition principle is revealed at the experimental level. Furthermore, the compressive strength of the concrete and the compressive strength of the steel tube in circular steel tube concrete columns are analyzed. The results indicate that there is a certain discrepancy between the calculated steel tube strength based on existing formulas and the experimental values. However, for safety considerations, a reasonable estimation of the steel tube compressive strength can be made. Utilizing the measured stress-strain values of concrete and steel, the existing stress-strain models are evaluated, and a more reliable stress-strain model is established.