Shear behavior of shear stud groups in precast concrete decks

In order to study the shear behavior of a group of shear studs placed on a composite beam, a total of 16 pushout tests were conducted, including 4 specimens with cast-in-place (CIP) concrete decks and 12 specimens with precast concrete (PC) decks. The primary parameters considered include reserved hole shape, loading path, and deck casting method. Through the experiment, the interface shear force-slip curves and the failure modes of shear stud groups (SSGs) in both CIP and PC decks under monotonic and repetitive loads were obtained. The results show that the shear behavior of the SSGs in square reserved holes is more favorable than that in circular reserved holes, the shear strength of SSGs in PC decks is smaller than that in CIP decks under monotonic loads. The general failure modes for a SSG are the cutoff of stud shanks and the damage of root welds at studs. While the shear strength of a SSGs in PC decks is similar to that in CIP decks under repetitive loads, ensuring the ductile failure mode of stud fracture and the shear capacity not smaller than that stipulated in the design code for reinforced concrete (RC) structures, even without using any rebar in a reserved hole. The peak interface shear force and the trend of interface shear force-slip curves under repetitive loads are also similar to that under monotonic loads, although the interface slip corresponding to peak force under monotonic loads is smaller than that under repetitive loads. The study results indicate that the SSG in a PC deck can be fully utilized and the existing design formulas almost may be utilized to calculate shear capacity of shear stud groups.