Static performance of stud shear connectors and UHPC in deck-to-girder composite connection

This paper presents an experimental evaluation of the static performance of ultrahigh performance concrete (UHPC) shear pockets for accelerated bridge construction systems. Specimens with/out shear studs were tested under static load. The shear pocket design replicated real bridge that was constructed with UHPC shear pockets. The relative slip, separation at the interface, as well as the strain in the shear studs were measured and reported. The results indicate the stud arrangement has a negligible effect on the shear capacity but it had a significant effect on the slip. The slip at the maximum load of the specimens with single layer of studs was approximately 68% higher than that of the specimens with grouped studs. The grouped studs also had a significant effect on the shear stiffness by increasing the stiffness by at least 60%. The strains in the shear stud near its head were only 26% of the yield strain which indicates the embedment length to be larger than what is needed and can be reduced. The stud load capacities were compared with the design code values and indicate that AASHTO LRFD design calculations and were not conservative and overestimated the shear capacity of the shear studs. Eurocode design code provided overly conservative results for specimens in this study. It was noticed that strength of the precast concrete plays a significant role in the failure patterns.