Estimation of friction contribution in the behavior of steel-concrete composite beams with flexible shear connectors

Abstract

A shear connector, developed to be applied to a composite beam whose steel profile is a thin-walled box profile, displayed much greater flexibility than the conventional welded shear connector, leading to particular issues in the composite beam behaviour. One of these issues is the role played by friction at the interface between the steel profile and the slab which, under particular circumstances, may be relevant for serviceability limit states and also for ultimate limit states. The Brazilian and American Standards do not yet recognize the friction contribution in the behaviour of composite beams, though they recognize this contribution in composite slabs. This paper presents the experimental tests carried out with and without friction contribution on simple supported composite beams with flexible connectors and the numerical models developed to simulate the behaviour of the tested beams. The experimental tests revealed significant increases in strength and stiffness of the composite beam due to friction contribution and the comparisons between numerical and experimental results displayed good correlations.

Estimation of friction contribution in the behavior of steel-concrete composite beams with flexible shear connectors

“…In the case of flexible shear connectors the contribution of friction between the slab and the steel profile may be relevant for serviceability limit states and also for ultimate limit states, provided that the beam span is relatively short and the slab stiffness is relatively large compared to that of the steel profile alone. These conclusions were drawn from previous analytical and numerical models allowing for the shear connectors' flexibility and friction between the slab and the steel profile (SILVA, 2009, QUEIROZ et al, 2009, OLIVEIRA, 2009, QUEIROZ et al, 2010. These results have not yet been included into the provisions of Brazilian (ABNT, 2008) and American Standards (AISC,2005) which do not recognize the friction contribution in the behavior of composite beams, only of composite slabs.…”

“…In a previous study, a less refined numerical model was developed to simulate the experimental tests in which shell elements were used to discretize the slab (QUEIROZ et al, 2010). Concrete stiffness degradation after cracking in the tension zone was not considered in this model.…”

Behavior of precast reinforced concrete columns subjected to monotonic short-term loading

“…Wolanski (2004) simulated the behaviour of reinforced and prestressed concrete slabs submitted to simple bending [16]. Queiroz et al (2014) developed numerical models of steel and concrete composite beams with flexible connectors to evaluate the contribution of friction at the steel-concrete interface [17]. Another line involving finite element models in the ANSYS software is based on the development of new finite elements (solid and plane) using user programmable features, which allow the inclusion of new material models that are not available in the library.…”