Steel Collar Connectors for TCC Floors: Interpretation of the Mechanical Behaviour Through Numerical Studies

The timber-concrete composite (TCC) system is a technology successfully used in many applications in historical buildings. Among the advantages, it requires short time of construction and it does not need the removal of the beams, what allows the preservation of the integrity of historical painted ceilings, if present at the floor intrados. TCC is composed by a timber beam and a concrete slab connected each other by specific dry connectors, like screws, nails and studs, which should be inserted into the timber beam through drilling. More recently, in order to avoid the perforation of the beams for the installation of traditional devices, an innovative reversible system is proposed, consisting in a steel collar that confines the beam without drilling it, thereby avoiding the timber damage, assuring the slip resistance by friction between the collar and the beam. The collar is equipped with a TC connector above. In this paper, starting from the reference experimental push-out test on a specimen of the proposed steel collar system, a monotonic numerical simulation is carried out by using the structural program ABAQUS. Therefore, the mechanical behavior of the system and of each component is analyzed and discussed. Finally, based on the results of the numerical analysis, the capacity design criteria of the system are proposed.