Beam–column composite connections under cyclic loading: an experimental study

Abstract

In this paper an experimental research on beam–column internal connections is reported. The studied connection consisted of a concrete filled steel tubular column and steel beams with endplates joined by embedded bolts. The slab was also considered in the prototype, comprising the major focus of the experimental program wherein the influence of the reinforcement ratio and the continuity of bars was analyzed. An innovative detail using steel sleeves is proposed to achieve the continuity of the slab reinforcement. The behavior of the proposed connection was compared to the behavior of the connection with conventional system with bars welded on the steel tube. Three large-scale specimens subjected to cyclic loading have been tested and their responses measured and analyzed. The results showed the good behavior of the proposed connection, mainly avoiding transfer of forces to the steel tube. Regarding the influence of the slab reinforcement ratio, it was observed a better behavior of the connection with higher ratio, preserving the initial stiffness after the loading cycles.