Shear connection of prefabricated slabs with LWC - Part1: Experimental and analytical studies

This paper studies the shear strength and load-slip behaviours of a recently developed novel steel-concrete composite flooring system (PUSS) with two different types of shear connectors while also using lightweight concrete. PUSS consists of a T-ribbed lightweight concrete floor and C-channel steel edge beams. The proposed shear connection system is using either web-welded shear studs only, or combined with horizontally lying steel dowels. This unique system further minimises its structural depth and results in ultra-shallow floors.

Eight full-scale push-out tests were conducted to investigate the connection under the direct shear force with three different concrete types (normal concrete, lightweight and ultra-lightweight concretes) and two different shear connection systems (web-welded shear studs only and horizontally lying steel dowels together with web-welded shear studs). Three types of failure were recorded from the push-out tests; shear failure with bending near the roots of the connectors, shear failure of the weld toe of shear studs, and concrete cracking. Among the conclusions, it was validated that the compressive strength of the concrete significantly influences the ultimate shear strength capacity loads while it is influencing the failure mode of the connection. The failure mechanisms of the shear connectors were extensively studied, which led to the development of a calculation method for the shear strength and load–slip behaviours of the new connectors embedded in lightweight concrete. The analytical results are compared with those predicted by modern codes of practices and available methods from the literature. It is concluded that the proposed formulae offer a reliable prediction.