Experimental Investigation on Behavior of High-Strength Light weight Concrete-Filled Steel Tube Strut Under Axial Compression

Abstract

This investigation was conducted for experimental and analytical study on the behavior of lightweight concrete-filled steel tube strut (short column) concentrically loaded in compression to failure. Sintagg (expanded clay aggregates) light-weight aggregate was used to prepare high-strength structural lightweight concrete of 40 N/mm2 grade. Sixty-four specimens were tested to failure to investigate the axial compressive behavior of lightweight concrete-filled tube strut (LWCFT). Different strut lengths, sectional sizes, and thickness were used to enumerate the influence of member geometry and constituent material properties on the structural behavior of CFT struts. Ultimate strength results were compared to current specifications governing the design of concrete-filled steel tube struts. This investigation provided a review of the current design rules for concrete-filled sections in Euro code 4 (EC4) and American standards (AISC). Consequently, deadweight of strut member was reduced by 25.30% as compared to normal concrete-filled steel tube strut. The buckling failure pattern for square CFT strut was observed as local buckling takes place, while for circular and rectangular CFT struts plastic buckling takes place. Also, it was observed that the experimental results were adequate to predict the current design specifications. Experimental results suggest that circular tubes offer substantial post-yield strength and stiffness, not available in most square or rectangular cross sections. The calculated confining strengths show that Euro Code-4 provides more realistic results than in case LWCFT strut under axial compression.