engleski

Numerical study of cold-formed steel-concrete composite floor system with demountable shear connectors

Except for the main advantage of the composite systems, which is the efficient utilisation of used materials, these structural systems are known for reusability, high degree of prefabrication and long- span capability. Because of these advantages, the range of applications of composite structures is continuously expanded. Since cold- formed steel sections have many benefits compared to hot-rolled sections, their implementation in composite systems has become more attractive to researchers in recent years. This paper represents numerical research on the bending behaviour of composite cold-formed steel- concrete beams. Spot- welding technology for connecting cold-formed steel elements and innovative demountable shear connections with bolts were used as a part of the LWT-FLOOR project at the Faculty of Civil Engineering, University of Zagreb, Croatia. Cold- formed steel elements are built-up beams with back-to-back profiles as flanges and corrugated webs. The obtained results provide the basis for implementing laboratory research on the proposed system. Experimental results of tensile base materials and spot welds behaviour were used to support numerical research. Numerical analyses were conducted in Abaqus/CAE, where the influence of the degree of shear connection, spot weld density, concrete type, steel cross-section thickness and the diameter of the shear connector were analysed. The performed analyses showed that the influence of the degree of shear connection and spot weld density have a significant impact on system behaviour. The influence of concrete type is negligible when comparing the models with the same spot weld density and full shear connection. The same influence becomes greater for models with the partial shear connection. In addition, results show that the thicknesses of the corrugated web and C profile highly influence the bending resistance of the analysed system. Corrugated web thickness results in the highest flexural stiffness and bending resistance in the case of tied steel elements. Furthermore, for steel beam elements connected by spot welds, the corrugated web thickness had a more significant influence on the beam resistance. Regarding the diameter of the shear connector, it is concluded that it has a negligible influence on the bending resistance of the analysed system due to the crushing of concrete for both diameters.

Composite beam, Built-up cold-formed steel beam, Spot welding, Parametric FE analyses

Best Student Presentation Award - Andrea Rajić: https://cfsrc.org/2022/10/19/colloquium-award- winners/