Experimental study of the short-term and long-term behavior of perfobond connectors

Recently, perfobond connectors for steel-concrete composite structures have received extensive research attention due to their excellent bonding and fatigue performance, and the construction convenience. However, the research on the long-term behavior of perfobond connectors was seldom reported. This paper presents the results of laboratory tests on perfobond connectors, including twenty short-term specimens and six long-term specimens. Parametric study was conducted to investigate the influence of the hole diameter in the connector, the number of the holes, the thickness of the connector, the concrete strength as well as the diameter of the transverse rebar on the shear performance of perfobond connectors. For the short-term test series, the failure modes of the connector, the load-slip response, the ultimate shear bearing capacity and the load-strain curves of transverse rebar were studied. For the long-term test series, the transverse rebar strain, the relative slip between the steel beam and the concrete slab and the stress around the holes with duration of loading were discussed. The shear performance of perfobond connectors after long-term loading was also investigated. Finally, based on the test data from both this paper and open literature, a model was proposed to predict the shear bearing capacity of perfobond connectors.