Ring-beam is a kind of through-beam connections where the steel tube is interrupted by a strengthening ring-beam while the reinforced concrete beams are continuous in the joint zone. The ring-beam is used to enlarge the connection zone in order to…
Ring-beam is a kind of through-beam connections where the steel tube is interrupted by a strengthening ring-beam while the reinforced concrete beams are continuous in the joint zone. The ring-beam is used to enlarge the connection zone in order to compensate for the possible decrease of the axial load-carrying capacity. However, due to brittleness of concrete, the durability problem arising from concrete cracking is a big challenge for this kind of connection. Engineered cementitious composite (ECC) is a class of high performance cementitious composites with pseudo strain hardening behaviour and excellent crack control. Substitution of concrete with ECC in the ring-beam region can efficiently avoid the cracking. Meanwhile, due to super high ductility of ECC materials, ECC outside the compression zone can provide persistent constraints on core regions, which effectively improves the axial carrying capacity and ductility of the connection. In this paper, six ECC ring-beams including three concrete ring-beams and three ECC ring-beams with various reinforcement ratio and height were tested under local axial compressive force. According to the test result, ECC ring- beams show good integrity throughout the test with no matrix spalling. The ring-beams made by ECC exhibited better axial load-carrying capacity, ductility and energy dissipation than concrete specimens, which is more obvious for specimens with on bars. Therefore, the application of ECC in the ring-beam is an effect method to improve the local axial compressive behaviour of this kind of connection.