Axial compressive behavior of a novel assembled joint connecting FCSRC columns and RC beams with pre-damage

Abstract

To promote the application of Fiber-reinforced polymer-confined steel-reinforced concrete (FCSRC) in new structures, a novel assembled joint connecting FCSRC columns and RC beams was proposed. The novel joint contained a concrete-filled-steel-tube stub column and a pair of ring plates with steel connecting beams. The joint was connected to FCSRC columns and reinforced concrete (RC) beams by end plates and high-strength bolts. Previous studies have revealed that the assembled joint could effectively connect FCSRC columns and RC beams with good seismic performance. However, research on this novel joint was not sufficient. Axial compressive performance and post-seismic residual resistance are also important structural issues that need to be addressed. This paper thus investigates the effect of pre-damage level and steel tube thickness for the joint on its axial compressive behavior. Results showed that with thinner steel tube thickness, more severe bulging was observed and the axial load and initial stiffness of the specimen was reduced. Besides, based on the test results and the finite element analyses, it is clear that the effect of pre-damage was negligible on the axial load–displacement behavior of the proposed joint. Lastly, a prediction model for the axial load-carrying capacity of the joint was proposed.