Confined Steel Brace for Earthquake Resistant Design

An experimental study of a passive energy dissipation tension-compression yielding brace or buckling-restrained brace has been conducted. The Confined Yielding Brace (CYB) consists of a steel yielding core confined within a tube filled with non-cohesive material. The external tube and confined non-cohesive material provide lateral stability to the core enabling the device to yield in compression as well as tension. This device is similar to the Unbonded Brace developed by Nippon Steel of Japan. Fourteen large-scale CYBs were tested to determine the effect of varied confining material, yielding core perforation blocking configurations, and displacement histories. Based on experimental results, Confined Yielding Braces produce relatively stable and symmetric hysteretic damping.