Bi-directional sub-structural pseudo-dynamic tests of a full-scale 2-story BRBF, Part 2: Compressive behavior of gusset plates

A full-scale 2-story single-bay buckling restrained braced frame (BRBF) was tested using bi-directional earthquake loads and substructure hybrid testing techniques. This paper is the second part of a two-part paper describing the design methodologies and the performance of the gusset plates used in the BRBF. Finite element buckling analysis suggests that the gusset edge stiffeners can effectively increase the compressive stability of the gusset. In the gusset design using the Whitmore's and Thornton's criteria, an effective length factor of 0.65 can be considered only when the stiffeners are installed at the edge of the gussets. Test results confirmed that the buckling of the gusset plates was completed avoided using the stiffener designs adopted for the specimen. Tests results indicate that the maximum gusset out-of-plane displacement can be estimated by multiplying the maximum BRBF out-of-plane story drift demand to the beam-center-to-gusset distance. Cracks were observed near the tip of welded gusset-to-column joints, suggesting that the seismic design of the gusset-to-column connections requires further study.