Research on the shear performance of groove-reserved prefabricated steel-concrete composite slab-beam connection

The groove-reserved slab-beam connection offers advantages such as high degree of prefabrication , good overall mechanical performance, and ease of construction, making it one of the most optimal solutions for building prefabricated composite beams. The construction process of this structure is as follows: steel beams with shear connectors and concrete slabs with reserved grooves on the underside are prefabricated in the factory, and after being transported to the construction site, the slab-beam connection is completed by pouring concrete into the grooves of the precast slabs. Existing studies on the shear performance and optimal design of groove-reserved slab-beam connections remain insufficient, limiting their practical application. To address this, five full-scale push-out tests were conducted, and finite element models of structures with new-to-old concrete interfaces were developed. The calculation results from design formulas in relevant codes were compared. The results indicate that when designing the shear capacity of this connection structure, both the shear capacity of the new-to-old concrete interface and the shear connectors should be simultaneously verified. Using Ultra-High-Performance Concrete instead of Shrinkage-Compensating Concrete as post-cast concrete increases the shear capacity of the new-to-old concrete interface by 9 %, while incorporating key-tooth structures at the grooves enhances the shear capacity by 13 %. Additionally, the effects of shear rebar quantity, interface roughness, and pre-compression force on the shear capacity of the new-to-old concrete interface were investigated.