Behavior of steel–concrete partially composite beams with channel type shear connectors

• Flexural behavior of partially composite beams with channel connectors is studied.
• Effect of partial composite action degree on strength and stiffness of beams is investigated.
• Behavior of connectors in beams is related to load-slip behavior from push-out tests.
• Small composite action results in major improvement in moment capacity and stiffness.
• Equations in AISC Specification overestimate service stiffness of beams.

This paper summarizes the findings of an experimental study investigating the flexural behavior of partially composite beams incorporating channel type shear connectors. Results from monotonic load testing of four full-scale steel–concrete composite beams and a steel beam are presented. The main effort focused on identifying the variation of strength and stiffness properties of beams with various degrees of partial composite action. Behavior of channel shear connectors in the composite beam specimens is related to those previously obtained from push-out tests of similar connectors. Finally, recommendations of the related AISC Specification on the strength and stiffness of composite beams are used for the assessment of the influence of the degree of partial composite action on flexural behavior. The experimental results revealed that even for beams with relatively low degree of partial composite action, major improvement on moment capacity and stiffness was obtained as compared to the steel specimen. The measured moment capacity of both the partially composite and fully composite beams agreed acceptably with the calculated capacities. The effective moment of inertia and the lower bound moment of inertia as specified by the AISC Specification were observed to overestimate the measured flexural stiffness of beams for all degrees of partial composite action investigated.