Numerical Investigations on Improving Beam-Column Joint Seismic Performances Using Replaceable BRFCPs

A replaceable buckling-restrained flange cover plate (BRFCP) was proposed to improve seismic performance of steel moment resisting frame beam-to-column joints. Quasi-static experiments showed that the use of BRFCP can significantly improve the beam-to-column joint strength as well as ductility. However, experiments can only be conducted on limited number of test specimens. In order to investigate more design parameters, finite element models of the tested joints are developed and validated. The validated finite element models are used to investigate effects from different BRFCP design parameters, such as core plate thickness, restraining plate thickness. The results show that: (1) the core plate thickness needs to be limited to an upper bound to avoid inelastic behavior at panel zone; (2) the restraining plate needs to be thick enough to provide effective restraining effects to the core plate; (3) increase restraining plate thickness does not have a significant effect to the joint load resistance; (4) the restraining gap size does not have significant effects to the joint ultimate strength.