Tensile–Shear Coupling Effect on Push-Out Behavior of Headed Studs under Cyclic and Fatigue Loads

Shear connectors play critical roles in the mechanical behavior of steel–concrete composite structures. Currently, the cyclic and fatigue performance of shear connectors under tensile–shear coupling effect are still unclear. This paper presents an experimental study on the mechanical behavior, damage mechanisms, and failure modes of shear connectors under cyclic and fatigue loads considering the tensile–shear coupling effect. Eight steel–concrete push-out specimens with varying tension–shear ratios were designed and tested to investigate the effect of tension–shear ratios on cyclic and fatigue performance. Acoustic emission technology was applied to evaluate the damage evolution process by tracking fracture events in real time. The test results show that increasing the tension–shear ratio significantly reduced stiffness, energy dissipation capacity, and fatigue resistance of the push-out specimens, revealing that the combined tension–shear effect is detrimental to the safety and capacity of steel–concrete composite structures. It is therefore necessary to consider the influence of the tension–shear coupling effect in structural design.