Resilient brace member with steel hook dampers: Development and performance evaluation

Steel braced frames are commonly used in earthquake-resistant designs due to their high strength and energy dissipation capabilities. However, the inevitable brace buckling at large deformation incurs high costs in aftershock rehabilitation. Therefore, a design modification to further improve the brace member structural performance is essential. This study focused on the development and performance evaluation of a novel resilient brace member designed for structural performance upgrading. This design integrates a pair of pre-separated brace segments and a pair of steel hook dampers (SHDs) that possess a curved tapered profile and uniform yielding mechanism via flexural mode when subjected to axial load. Two series of cyclic loading tests on the SHDs and brace members with various SHD dimensions were carried out to evaluate the cyclic performance of the proposed designs. The test results showed that the SHDs possessed stable load-carrying mechanisms and the proposed brace member designs exhibited significant strength and energy dissipation capacities. The test results also showed that significant equivalent viscous damping, approximately 35% to 42%, was adequately achieved in the brace members. Simultaneous enhancements in equivalent viscous damping, strength and energy dissipation validated the applicability of the proposed method to earthquake-resistant designs.