Experimental Investigation of Bolt-Configured Naturally Buckling Braces with Gusset Plate Connections

The Naturally Buckling Brace (NBB) is a steel brace developed by the writers, which consists of a high-strength and low-yielding steel channel arranged in parallel with an intentional eccentricity along the brace length. The NBB deforms with a novel mechanism providing ductile seismic behavior, and overcomes the deficiencies of conventional steel braces. To further improve the construction of NBB for practical applications, the present study examines the following configurations: 1) use gusset plate connections designed to accommodate inelastic rotations instead of mechanical pins; 2) use bolts instead of welding to connect the two channels together; 3) apply intentional eccentricity along the brace length with the aid of a steel block or steel knife plate. The efficiency of these suggestions was evaluated by conducting cyclic quasi-static tests in three specimens. The test results showed that the proposed configurations keep the beneficial seismic performance of the original NBB configuration, experiencing similar cyclic responses mainly up to 2% story drift.