Axial compressive behavior of the PEC slender columns with lightweight aggregate concrete

Abstract

To greatly facilitate hoisting and assembly of prefabricated partially encased steel-concrete composite (PEC) columns, lightweight aggregate concrete (LAC) is applied into the PEC columns to form the partially encased composite columns with lightweight aggregate concrete (PEC-LAC). This paper reported experimental studies on the axial compressive behavior of PEC-LAC columns with various slenderness ratios. Following this, finite element (FE) modeling methods considering geometrical and residual stress imperfections were developed to reproduce the test responses. FE analysis was carried out to investigate the effect of geometrical and material parameters on PEC-LAC slender columns subjected to axial compression along the minor axis and major axis. It was found from the contact stress analysis that PEC-LAC slender columns with axial loading along the major axis provide a stronger confinement effect than that with axial loading along the minor axis. Based on the comparison of reduction factors between the test/FE and calculated results, the buckling curve of AISC 360 and the buckling curve (b) of T/CECS 719 can economically and conservatively describe the buckling curve of PEC-LAC slender columns regardless of the flexural buckling direction; the buckling curves (b) and (a) of EC4 were recommended to predict buckling curves of PEC-LAC columns with flexural buckling about the major and minor axis, respectively.