Push‐out tests of innovative shear connection in CFS‐concrete beams with corrugated web

Abstract

This paper presents an experimental investigation of the LWT‐FLOOR composite floor system, focusing on the behaviour of corrugated‐web shear connections in built‐up cold‐formed steel (CFS)‐concrete beams. The system consists of built‐up steel girders with spot‐welded CFS profiles and a concrete slab, where the shear connection is achieved by embedding a 1.5 mm thick corrugated web of the steel girder into the concrete slab, ensuring effective load transfer between steel and concrete and promoting composite action between the two materials. Two types of push‐out specimens were tested: three with normal‐weight concrete and three with lightweight concrete. Key performance indicators, including failure modes, shear resistance, ductility, and initial stiffness, are evaluated. Most specimens showed high shear capacity and ductility compared to conventional solutions. However, two specimens (one per group) failed prematurely due to poor spot weld quality. The primary failure mode was local deformation of the embedded web, accompanied by concrete cracking and partial separation from the steel profiles. Results highlight the interaction of multiple failure mechanisms and the potential of this connection as a robust solution for composite floors with both concrete types. The study emphasises the importance of proper design and quality control of spot welds.