Influence of Shear Connection and End Supports onto Self-vibrations of Cold-Formed Steel Concrete Composite Floor

Cold-formed steel composite floors are lightweight systems whose application increased in the last few decades. According to the design guidelines, the frequency of floor systems should be more than 4 Hz while in the case of light steel floors, the natural frequency of the system should be in the high frequency range above 8 Hz. The main focus of this paper is to investigate the vibration performance of an innovative lightweight composite floor system called LWT-FLOOR. The LWT-FLOOR system is composed of spot-welded built-up cold-formed steel elements that are connected to a lightweight concrete slab. Based on laboratory tests material properties of all components of the system are obtained and the finite element model of cold-formed steel concrete composite floor is created to investigate its vibration behaviour. Numerical analyses were conducted in Abaqus/CAE, where after mesh density verification, the influence of the degree of shear connection, spot weld density, concrete type and class, steel channels cross-section thickness and the arrangement and diameter of the shear connector were analysed. The results show that the flexural rigidity of the system and vibration characteristics can be improved by changing those parameters, especially by changing steel channel cross-section characteristics and support conditions from nominally pinned to nominally rigid.