Journal article

Gusset Plate Connections for Naturally Buckling Braces

A Naturally Buckling Brace (NBB) is a steel brace which consists of a high-strength and a low-yielding steel channel arranged in parallel with eccentricity acting along the brace length. To enhance NBB fabrication, three connecting design details of the NBB are proposed: 1) gusset plate (GP) connections for connecting the brace to the steel frame; 2) bolting connections to tie the two channels together; 3) steel block, knife plate, or angle connections to apply eccentricity along the brace length at the NBB ends. Four brace specimens were subjected to cyclic quasi-static loading to evaluate the proposed configurations. Although GPs provided some rotational restraint, the new design maintained all the advantages of the original concept especially until 2% story drift, while rupture of neither the brace or GP occurred up to 4% story drift. A simple design equation for estimating the post-yielding stiffness is proposed. The equation is reasonable for the range of slenderness between 40 and 70 and for the ratio of strength between the two channels from 3 to 5.


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