Experimental study of slender LCFST columns connected by steel linking plates

This paper presents the results of an experimental investigation of L-shaped columns composed of concrete-filled steel tubes (LCFST columns) connected by steel linking plates. As a new kind of composite column, the fundamental struc- tural behavior of LCFST columns connected by steel linking plates is discussed in this paper. Eight large-scale LCFST columns were constructed and loaded under either concentric axial compression or biaxial eccentric compression up to failure. Slenderness ratio, thickness of the steel linking plates and load eccentricities were all studied within the experi- mental program. The relationships of load versus longitudinal displacement, lateral deflection at mid-height, longitudinal strain at mid-height etc. are presented. It is demonstrated that specimens with larger slenderness ratios or eccentricities have lower ultimate load capacities, as expected. It is also demonstrated that the steel connection plates, also as expected, have a considerable influence on confining lateral deflections of the mono CFST columns and that they significantly contribute to the columns' ultimate carrying capacity. Predictive formulas for calculating the ultimate loads of LCFST columns connected by steel linking plates are proposed based on modifications of the ANSI/AISC 360-05 guidelines.