Experimental study on seismic performance of CFST frame structures with energy dissipation devices

• Three specimens under vertical compression and lateral cyclic load are tested.
• The mechanical behavior of CFST frame with BRBs was improved effectively.
• The strength and stiffness degradations of the CFST frame have been slowed down.
• The ultimate load and energy absorption capacity of structure have been improved.
• The BRB increases the seismic strengthening of the CFST frame.

Three model structures of concrete filled steel tubular (CFST) frame with a scaling ratio of 1:4 were designed and tested in the present study. The structural elements of the three model structures had same dimensions. Two of them were installed with a new triple-steel tube buckling-restrained brace (BRB). The seismic behaviors of the structures were evaluated by testing them with combined vertical constant compression and lateral cyclic loads. The structural performance, such as the hysteretic behavior, skeleton curve, strength degradation, stiffness degradation, energy dissipation capacity and strains at different locations of the model structures with and without BRB was discussed in detail. The results show that the CFST frame with BRB significantly improved the load bearing capacity, the deformability and the energy dissipation capacity, with the strength and stiffness degradation being obviously reduced. The CFST frame with BRB has preferable mechanical behavior and failure mode. It was verified that the new triple-steel tube BRB improves the seismic performance of CFST frame structures.