Analysis of rectangular shaped collar connectors for composite timber-steel-concrete floors: push-out tests

The paper deals with the experimental analysis of an innovative connection system for composite timber‐steel‐concrete floors. The connection device consists of a collar composed by two or more parts, astride the timber beam, bolted together at adjacent wings. A rubber layer is interposed at the collar‐beam interface. The slipping action transmission is guaranteed by the superior wings of the collar or by a steel stud, purposely welded to the collar in the upper part, which are immersed in the concrete cast. In this paper push‐out monotonic tests on several rectangular‐shaped configurations of the connection system are presented, being part of a more comprehensive experimental campaign, aimed at the system performance evaluation and optimization. First, the preliminary numerical analyses, meant to define both the best geometrical characteristics of the specimens and the configuration of the testing apparatus, are illustrated. Then the push‐out tests, considering subsequent improvements of the connection system are detailed. The connection behaviour is discussed in terms of force‐slip relationship