Cumulative Ductility and Strain Demands of Steel Buckling-Restrained Braces Subjected to Earthquake Displacement Histories

This paper evaluates the seismic-induced deformation demands in steel BRBs, including cumulative plastic axial deformation and peak strain demands. The loading protocols typically used for qualification testing of steel BRBs in North America and Japan are first described. A prototype buckling-restrained braced frame is then selected and designed following the Canadian steel design standard. A numerical model of the frame is developed and used to perform a series of nonlinear response history analyses under potential sources of seismicity in the west coast of Canada. The results of these analyses are finally used to examine cumulative ductility, strain, and force demands of BRBs. Furthermore, recommendations are made for the development of loading protocols based on simulated earthquakes for future full-scale experimental testing of steel BRBs.