New shear connector for Open Web Steel Joist with metal deck and concrete slab floor system

The composite floor system, consists of a concrete slab poured on steel sheets, supported over Open Web Steel Joists (OWSJ); is widely used in commercial and industrial buildings. To achieve the desirable strength, shear connector (studs) have to be welded on the OWSJ to ensure composite action of the three components. Extending the application of this composite floor system to residential buildings, alternative shear connectors such as puddle-welds and Hilti-screws would greatly reduce the expense and accelerate the construction. Yet the current design codes consider these alternates structurally inadequate due to lack of research. The objective of this research is to investigate the ability of puddle-welds and Hilti-screws to develop composite action for building applications. The experimental program consists of testing two full scale composite decks, each consisted of two OWSJs supporting a 2.4 m wide concrete slab over 6.7 m span. Puddle welds and Hilti screws were used as main and only shear connector. Both test prototypes were tested until failure under different combinations of static and fatigue load cycles. Test results showed that significant composite action is developed using puddle-weld shear connectors and their behaviour meets the serviceability and ultimate strength requirements for residential applications.