Influence of concrete material ductility on shear response of stud connections

This paper presents an experimental study on the influence of concrete material ductility on the shear response of stud connections, including failure mode, ultimate strength, slip capacity, and structural integrity. A series of pushout specimens were tested for this evaluation by using a unique strain-hardening fiber-reinforced engineered cementitious composite (ECC). Tension-softening steel fiber-reinforced concrete (SFRC) and normal concrete (both plain and steel bar reinforced) were adopted as the reference materials. The experimental results show that the, stud connections with ECC exhibit more ductile failure mode, and a higher ultimate strength and slip capacity compared with connections with other concrete materials, in addition to a much improved structural integrity. The superior ductility of ECC was clearly reflected by microcrack development near the shear studs, suppressing the localized fracture mode typically observed in other concrete materials. This significant enhancement of ductility suggests that the use of an ECC material can be effective in redistributing loads among the shear studs and in improving composite action between steel girders and concrete bridge decks.