A new modular buckling restrained brace for seismic resistant buildings

This paper proposes an innovative BRB as a new energy dissipation device for earthquake resistant buildings. Its steel yielding core is modular, and this very design enables the yielding force and plastic deformation to be adjusted according to building requirements. Based on connecting several Seriated Modules, which are comprised of any constant number of Shear Basic Dissipation Units, deformation is proportional to the number of Seriated Modules and force to the number of Shear Basic Dissipation Units (on the Seriated Modules). Assembling the brace consists of sliding the greased yielding core into the restraining unit and coupling it with pins, thus providing easy inspection or replacement of the dissipation unit if required. Fully-scaled prototypes have been tested under reversal cyclic displacements and the hysteretic response has been proved stable and with a high cumulative ductility. The main parameters are the yielding force and the yielding displacement; which can be predicted with simple expressions. A methodology to design a restraining unit able to tackle of buckling by taking into account the initial sway deformation and the functional gap between the yielding core and the restraining unit is proposed. The hysteretic behavior has been simulated with conventional FEM software.