Effect of rebar strength in Y-type perfobond rib shear connectors

Rebars improve composite structure constructability and efficiency. Transverse rebars in the Y-type perfobond rib shear connector influence both shear strength and ductility. Performance characteristics of Y-type perfobond rib shear connectors with various transverse rebar strengths and diameters need to be identified. Push-out tests were done with Y-type perfobond rib shear connectors with various transverse rebars. Strain gauges monitored the strain histories with both push force and relative slip between the perfobond rib and composite concrete block. The concrete block surface was photographed to confirm the surface crack formation time and pattern. Strain histories indicate that surface cracks initiated after the nominal yield strains of the rebars were exceeded. Shear resistance can be increased and the surface crack formation delayed by using high-strength transverse rebars. However, a balanced design is needed to achieve shear resistance and ductility. Excessive strength transverse rebars may cause early damage on, and failure of, the Y-ribs.