Parametric push-out analysis on group studs shear connector under effect of bending-induced concrete cracks

• We executed a parametric push-out analysis on group studs shear connector.
• It concerned effect of bending-induced concrete cracks on group studs' behavior.
• Bending-induced concrete cracks, concrete strength and stud size were parameters.
• Bending-induced concrete cracks tend to reduce stud shear stiffness.
• A method for estimating the stiffness reduction has been proposed and discussed.

Arranging shear studs in group is known for the constructional and economical advantages in steel and concrete composite structures. Nowadays, many composite bridges are constructed with wide transverse concrete cantilevers and web spacing, leaving resulted transverse bending-induced residual tensile concrete cracks. Its effect on group studs has not been fully clear. In this case, a parametric push-out FEM analysis with damage plasticity models has been executed. It concerned the mechanical performance of group studs under effect of bending-induced concrete cracks. In this study, bending-induced concrete cracks, concrete compressive strength, stud dimension were the parameters. It mainly showed that bending-induced concrete cracks caused stud shear stiffness reduction since the shear load transfer from stud to concrete during push process had been unfavorably affected by these cracks. Furthermore, the relationship between bending-induced concrete cracks and stud shear stiffness reduction has been described by equation from regressing the analysis results. Together with the proposed simplified analytical method of evaluating concrete crack depth, the study provided a possible way for engineering design and maintenance dealing with bending-induced concrete crack effect on stud shear connector. Finally, stud strength comparison between FEM results and evaluations based on several specifications indicated that engineers should pay attention to the effect of bending-induced concrete cracks.