Equations to predict the shear connection capacity of composite beams with slender profiled steel sheeting. (LAC19.F)

The rules of EN1994-1-1 for shear connections in composite beams with deep profiled
sheeting sometimes lead to an overestimation of the load bearing capacity of the respective shear
connection. The estimation of the impact of the sheeting shape on the calculated connection resistance
is based on test results from the late seventies until the early nineties. Meanwhile, new products have
appeared on the market with the target to reduce the volume and weight of the concrete in order to
maximize the slab efficiency. However, the corresponding effects onto the shear connection have been
underestimated because the use of deeper and more narrow deck rib lead to a more slender profile with
a changed failure behaviour. Instead of the shearing-off failure of the stud, a combination of concrete
cone failure and plastic bending of the stud – with one or two plastic hinges - was identified in laboratory
tests.
Based on the observed failure mechanisms, a new mechanical model with respective analytical
equations for the shear resistance of headed studs in profiled steel sheeting was proposed. The new
model extends the yield hinge mechanism, which was developed by Lungershausen [1], to more precisely
predict the formation of the number of yield hinges depending on the mechanical and geometrical
properties with the support of a finite element model. The complete equations consider the geometry of
the stud and the steel decking as well as the material strengths of the stud and concrete. The statistical
evaluation shows a good accordance with the developed model and analytical design equations.
This contribution presents the new design equations and their background describing the mechanical
model, the numerical study and statistical evaluation of push-out test results.