Experimental study on ultimate strength of bolted L shaped sleeve joints between CFS lipped channel sections

Abstract

This study aims to understand the behavior of bolted L shape sleeve joint connecting two Cold-Formed Steel (CFS) channel sections. A total of thirty-two specimens were experimentally tested under three-point bending. Three different series namely, (A) control specimen with two different span lengths, (B) sleeved specimen with the flange of sleeve connector capping the compression zone, and (C) sleeved specimen with the flange of sleeve connector capping the tension zone were tested. The parameters considered in this study include (i) the span length (Lt), (ii) sleeve length to section depth ratio (β), and (iii) thickness of sleeve connector (LS). The experimental results revealed that the ultimate moment resistance of specimens with a 2.5 mm thick sleeve connector was 19 to 73% higher than 2.0 mm thick sleeve specimens. The moment capacity of series C specimens was about 90–103% of that of the series B specimens. Based on the experimental results, design predictor equations were suggested to determine the moment resistance of sleeve specimens with respect to β. In addition, reliability studies were done for test series B to determine the safety and resistance factors for allowable strength design (ASD) method and load and resistance factor design (LRFD) method respectively. The equivalent and design uniformly distributed load (UDL) was determined based on the combined effect of shear and bending.