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Abstract
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Conventional buckling restrained braces used in concentrically braced frames are expected to yield in both tension
and compression without significant degradation of capacity under severe seismic ground motions. On the
other hand, a newshort core buckling restrained brace systemcould be introduced as an alternative for a conventional
full core BRB. In a short core BRB (SCBRB), the core element is built shorter than usual. Therefore, for a given
story drift, the core accepts bigger axial strains compared to a conventional (full core) BRB. A short core BRB
seems to be easily fabricated, inspected, and replaced after a severe earthquake. The purpose of this study is to
show how this type of buckling restrained braces is feasible. Reducing the core length in a buckling restrained
brace may result in a shorter encasing member, decrease in frictional forces acting at the core and buckling
restraining mechanisminterface, and, as a consequence, reduction of the compression strength adjustment factor
in the brace. This paper numerically investigates the seismic behavior of short core buckling restrained braced
frames. The minimum core length of BRB is determined by considering the low cycle fatigue life of the core
plate and the maximum anticipated strain demand under standard loading protocol. Nonlinear time history
analyses were also performed on four and ten story prototype buildings equipped with full core (conventional
BRBs) and short core BRBs and the story drifts were compared. The results showed that the SCBRB system is
partially able to reduce the story and residual story drifts in the braced frames. In addition, SCBRBs sustain
large plastic deformationswithout crossing the lowcycle fatigue life borders or instability of the encasing system.
However, the economic and practical aspects of using SCBRB seem to be more distinct in comparison to its
mechanical characteristics.
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