Novel demountable embedded bolted shear connectors in steel–concrete composite beams

In this study, the behaviour of demountable steel–concrete composite connections where bolted shear connectors are installed is assessed through push-out tests. The connection nuts are embedded with bolts in the connection hole of the prefabricated concrete slabs and filled with grout. Twelve steel–concrete composite connections are designed, made and tested to assess the behaviour of the composite connection subject to the bolt diameter, bolt strength and concrete strength effect. For comparison, two specimens having welded shear studs, the most common connector type, are also fabricated and tested. In all samples, the four main parameters of connection behaviour – the ultimate force, the ultimate slip, the slip corresponding to the maximum force and the initial stiffness – are calculated and compared. The preparation and fabrication of specimens, the testing procedure, the test set-up and the instruments applied are described, and details of the results of the push-out tests are tabulated. The test results indicate that the bolt diameter and strength, next to the concrete strength, have a considerable effect on the composite connection behaviour. Finally, to find the ultimate strengths for the embedded bolt shear connectors, a new design equation has been proposed using a regression analysis of the experiment’s data.