Experimental and numerical studies of axially loaded square concrete?encased concrete?filled large?diameter steel tubular short columns

This article presents experimental and numerical studies on the axial compressive behavior of square concrete-encased concrete-filled steel tubular (CECFST) short columns composed a circular inner tube. Tests six full-scale CECFST with tube diameter varying from 320 to 500 mm were carried out study influences sectional thickness CFST their performance. A theoretical model is developed using fiber analysis method validated against large test database. The accuracy various codified design models evaluated simple proposed calculate ultimate strengths. Test results show that have improved load carrying capacity can sustain loads without significant strength degradation. In addition, increasing significantly improves composite action concrete column, which increases by 27.3%. However, rate increase in core column has been found be higher for smaller local slenderness ratio. ductility influenced spacing stirrups. Furthermore, suggested this provide better estimation than models.