Design shear resistance of headed studs embedded in solid slabs and encasements

This paper presents the results from reliability analyses on the design resistance of headed stud connectors embedded in solid concrete slabs and encasements. The present study substantially extends the earlier reliability work for Eurocode 4 by considering a database of 242 push tests, which permits the results presented to be considered valid over a wide range of characteristic compressive concrete strengths (8 ≤ fck ≤ 90 MPa) and stud diameters (12.7 ≤ d ≤ 31.75 mm). As well as considering the performance of the existing Eurocode 4 design model, two alternative design models were also studied. Although the design models for steel failure performed well, it was found that the current target value of γV = 1.25 was not justified in the design models for concrete failure. In response to this finding, the design models were modified to ensure that the target value was delivered. In the interests of harmonization between the Eurocodes, further improvements were made to enable design equations to be proposed that deliver a uniform value for the partial factors, which may be considered worthy for inclusion within the second generation of Eurocode 4. Finally, from the significant number of tests considered in this paper, a revised procedure is presented for evaluating the characteristic resistance of stud connectors from small numbers of nominally identical push tests.