Development of Improved Shear Connection Rules in Composite Beams. New design rules for shear connector resistance in composite beams with deep rolled sheeting for resource efficient construction (DISCCO)

A newly conducted series of push-out tests with modern deep steel decking shows the insufficiency of the presented analysis methods of the stud shear resistance, as the predictions were in general non-conservative. Furthermore, depending on the geometry of the shear connection, a new failure mode was observed: Rib pry-out failure. Investigation on concentric and eccentric transverse loading of push-out specimens, to consider the loading conditions of a real slab, show in general beneficial influences on the load-slip behaviour. Based on the behaviour of the studs in push-out tests, equations for the shear connector resistance based on the failure modes are developed. A combined bending failure of the shear stud and the concrete rib is assumed. The observed failure modes in the tests are considered by different yield-lines of the shear stud. The shear resistance of the pure stud gives the upper bound for the shear connector resistance. The new equations show a good correlation to test results and are safe for modern types of steel decking. In comparison to [DIN EN 1994-1-1, 2010], the field of application is extended by the stud position, as in [Konrad, 2011], and deeper decking, as in [Lungershausen, 1988]. The analysis of the bending resistance of two accompanying beam tests confirms the accuracy of the new shear stud resistance. The beam tests have very low degrees of shear connection. The end-slip at ultimate load exceeds the limiting slip of 6mm, but at 95% of ultimate load the limiting slip is satisfied. A numerical model for composite beams is verified against the test results. The model considers the shear studs as non-linear springs. A simplified load-displacement curve is presented and verified against real load-slip curves. Research Assistant: Sebastian NELLINGER PhD-Thesis Title: On the behaviour of shear stud connections in composite beams with deep decking PhD-Thesis URL: https://hdl.handle.net/10993/24468