Seismic Performance of Three-core Buckling-Restrained Braces An Experimental Investigation

Abstract

Ordinary buckling-restrained braces have a single-yielding core. A buckling-restrained brace (BRB) with three parallel yielding cores and different yield strengths is, however, introduced in this paper that will expectedly exhibit an improved seismic behavior. The new BRB was constructed using three-yielding steel cores with the different yield strengths of 180, 240, and 360 MPa to be subjected to experimental tests of cyclic axial loading in accordance with the ATC-24 loading protocol. The results obtained were subsequently compared with those obtained for equivalent single-core BRBs. The three-core brace was observed to yield an area of hysteresis loops/dissipated energy considerably larger than that produced by the equivalent single-core BRB. Moreover, the cores with lower yield strengths tended not only to yield sooner but also to dissipate the input energy, while those with higher yield strengths limited both the story drift and the chances of a structural collapse. Finally, the three-core BRBs recorded energy absorption rates and damping ratios by 16.3% and 8.8%, respectively, higher than these of the single-core brace. © 2021, Shiraz University.