Calibration of resistance of shear connectors in troughs of profiled sheeting

Where a composite floor slab is supported on a composite beam of steel and concrete, shear connection is provided by studs in troughs of the sheeting. The resistance of these studs to longitudinal shear depends on over 20 parameters, of which 15 appear in the mechanical models for shear resistance of Johnson and Yuan, published in 1998. These models have been revised. The mean of 213 ratios of test/predicted shear resistance is now 1·03. For six layouts of studs, the variation of the ratios is lower than that of ratios predicted using the design methods of Eurocode 4. The Eurocode provides the intended margin of safety, based on push testing. Resistances to BS 5950-3-1 are on average 19% higher, but experience with it has been satisfactory. This paradox is discussed, with reference to tests on beams and to current anxiety about slip capacity.