Experimental and analytical assessments on flexural behaviour of CTLST composite beams

This paper reports a series of experimental and analytical assessments on the flexural behaviour of cold-formed thin-walled lipped-channel section truss (CTLST) beams with profiled steel sheeting-concrete (PSSC) slabs or autoclaved lightweight concrete (ALC) slabs. Three test parameters were studied, including the floor type, the U-shaped shear connector, and the connection type among CTLST members. Besides, testing phenomena, failure modes, load versus deflection curves, and strain response for these CTLST composite beams were also analyzed. The experimental data showed that flexural strength of CTLST composite beam was significantly increased by adopting reliable connection type; bond performance of the interface between the profiled steel sheeting (PSS) and concrete slab was improved by erecting U-shaped shear connectors. These CTLST composite beams were in accordance with specification recommendations of deflection limits. In addition, three-dimensional finite element (FE) modelling of CTLST composite beams were developed and verified by test data. Effect of material and geometrical parameters on the flexural feature of the CTLST beams with PSSC slabs was explored. Finally, a simplified method, which was verified by the tested and simulated results, was proposed to predict the mid-span deflection of the CTLST composite beam using reliable connection type under serviceability loads.