Seismic behavior of steel-reinforced recycled concrete inner-beam-column connection under low cyclic loads

This article presents the results of low cyclic loading tests on steel-reinforced recycled concrete inner-beam-column connections, including four 1:2.5 scaled specimens with different replacement rates of recycled coarse aggregates. The main objective of this study is to evaluate the seismic behavior of steel-reinforced recycled concrete inner-beam-column connection based on the seismic tests of the four specimens under low cyclic loads with vertical axial force. The main design parameter of the beam-column connections in this research is the recycled coarse aggregate replacement percentage. The crack status, failure modes, hysteresis loops, skeleton curves, energy dissipation, capacity stiffness of degradation, and ductility of steel-reinforced recycled concrete inner-beam-column connections are presented and analyzed. The results indicate that the main failure pattern of the steel-reinforced recycled concrete inner-beam-column connection is the shearing diagonal compression in the beam-column connection zone. As the recycled aggregate replacement percentage increases, both the bearing capacity and ductility of the steel-reinforced recycled concrete beam-column connections decrease to some extent. However, the seismic behavior of the steel-reinforced recycled concrete inner-beam-column connection does not degrade significantly compared with the ordinary steel-reinforced concrete beam-column connection.