Uniaxial Behavior and Structural Performance of Diagonally Stiffened CFST Stub Columns

Abstract

A novel concrete-filled steel tubular section with diagonal strengthening bars was introduced in the current study. It is constructed from a circular steel tube with strengthening bars placed diagonally opposite from one top end to the bottom end. Analysis was done on specimens of diagonally stiffened concrete-filled steel tubular columns to determine the load-bearing capacity, load versus deformation behaviour, stress distribution, and failure pattern. A parametric study was also carried out to ascertain the impact of the steel casing's outer diameter and thickness, concrete strength, and stiffening scheme on the suggested concrete-filled steel tubular's behaviour. The current evaluation's findings indicate that the column sections'geometrical and material properties significantly impacted the uniaxial performance of concrete-filled steel tubular sections with diagonal stiffeners. Increasing the diameter and grade of diagonal stiffeners improved the peak loading capacity and load versus strain graph of concrete-filled steel tubular columns with diagonal strengthening bars. In addition, the design relations given by the current design standards were altered, and new design equations were used to predict the load capacity of concrete-filled steel tubular columns that were diagonally stiffened. The results showed that every updated design equation from the design codes was determined to be in good agreement with the outcomes of the analysis. With the recommended strengthening strategy, the amended Eurocode design equation results demonstrate a more accurate and consistent prediction of the load capacity of concrete-filled steel tubular columns.