Cyclic loading test of three-bay RC space frame strengthened with X-shape RC braces

Previous studies showed improved seismic performance of reinforced concrete (RC) plane frames by adding RC braces. However, in literature, the studies on the efficiency of RC braces for the improvement of seismic performance of RC space frame (RCSF) are very limited. This paper presents the experimental results on two 1/4-scale, two-storey and three-bay RCSFs under cyclic loading, i.e. a control RCSF and another RC X-braces strengthened RCSF (termed as CBRCSF). The test results show that compared with the control frame, the seismic performance of the CBRCSF was improved significantly in terms of lateral strength, stiffness degradation and energy dissipation capacity due to the addition of RC X-braces. Moreover, the CBRCSF could continue to bear loads after the rupture of the RC braces, thereby revealing redundancy of the CBRCSF because of the use of RC X-braces.