Performance of LWT‐FLOOR Steel‐concrete Composite Floor Beams: Full‐Scale Experimental Study

Abstract The paper presents results of an experimental campaign of the innovative floor system LWT‐FLOOR developed at the University of Zagreb, Faculty of Civil Engineering, Croatia, aiming to address challenges regarding the reuse and recycling of composite structures. The system consists of built‐up steel girders with four cold‐formed C profiles connected by spot welds to the corrugated web, additional shear plates near supports and a lightweight aggregate concrete slab connected with a demountable shear connection realised with structural bolts. This paper summarises experimental findings regarding the system components and detailed results regarding six bending tests of 6 m long steel and composite girders. The key system performance indicators regarding bending capacity and stiffness, failure modes, deformations and concrete slab end slip are investigated. The results show that the failure modes of beams are complex and influenced by the height of the girder cross‐section, the thickness of steel elements and consequently, the characteristics of spot welds. Four specimens (two steel and two composite) show expected results regarding preliminary numerical studies, while two specimens (one steel and one composite) failed due to the premature failure of spot welds.