Lateral Seismic Performance Assessment of CFST-RC Hybrid Frame Structures

Concrete-filled steel tube (CFST) columns are widely used in multistorey building structures due to their improved axial load-carrying capacity. Extensive studies have been conducted to explore the energy dissipation potential, load-resisting capacity, and displacement ductility of CFST columns at the component level. These columns are often adopted in conjunction with reinforced concrete (RC) columns in the building frames. This paper focuses on the seismic performance assessment of hybrid frames comprising CFST columns in the lower storeys and RC members in the upper storeys. A six-storey three-bay frame configuration with CFST columns terminating at various levels has been considered for the study. The study frame has been numerically analysed in computer software. Nonlinear static procedure (NSP) or pushover analysis was performed to assess the lateral-load resisting behaviour of the frames. By comparing the seismic performances of a hybrid CFST-RC frame and a conventional RC frame, this study concludes that the former demonstrates superior seismic performance in terms of lateral-loadcarrying capacity and cost-effectiveness. The findings provide valuable insights for designing and implementing hybrid CFST-RC frame structures in multi-storey buildings, enhancing our understanding of their lateral performance.