Push-out tests of demountable headed stud shear connectors in steel-UHPC composite structures

Previous studies show that welded shear connectors in steel-ultra high performance concrete (UHPC) composite structures have poor ductility, which cannot satisfy the requirement of Eurocode 4 for ductile design. This paper presents a series of tests on demountable headed stud shear connectors in steel-UHPC composite structures, which can be employed in prefabricated building structures and bridge decks. This type of demountable stud shear connectors can make structural components recyclable and environment-friendly. The effects of the shank diameter and aspect ratio on failure modes, initial stiffness, ultimate strength and ductility of the shear connectors are investigated through push-out tests. Five groups of the connectors each with three specimens are tested considering deviations of the specimens due to material discreteness and manufacturing errors. Design formula for the shear strength of the demountable stud connectors is proposed, and design recommendations are also presented based on the experimental results.