Seismic performance evaluation of the ceiling-bracket-type modular joint with various bracket parameters

In this study, the seismic performance and inelastic behavior of joints were investigated using the bracket thickness, depth, and stiffener of the ceiling-bracket-type modular system as parameters. The performances of the joints were evaluated through a cyclic loading test and the nonlinear FEA. The initial stiffness, maximum flexural strength, failure mode at the ultimate stage, energy dissipation capacity, and inelastic behavior were analyzed, and it was determined whether the strong-column/weak-beam-type mechanism occurs at the joint. The results of the analysis were compared with those of the theoretical and FE models, respectively. For the comparison of the seismic performances, the flexural strength of the joint at the 0.04 and 0.05 rad inter-story drift ratios, which exceed the plastic moment, was investigated. From the comparison results, the standard specimen had a sufficient structural performance compared to the reference model, which was a welded joint. The joint was shown to be capable of maintaining a seismic performance higher than 80% of the plastic moment, and showed strain curves pointing to a strong column-weak beam behavior. In the joints, the initial stiffness was increased with a higher bracket thickness. In addition, the maximum flexural strength showed a large change in the loading direction due to the ceiling bracket. If the number of stiffeners is reduced, the joint will have both reduced initial stiffness and reduced maximum flexural strength. The bracket-type modular building was shown to be an effective and dependable modular system for resisting seismic loads, and the energy dissipation capacity of the standard specimen was shown to be higher than those of the other modular joints