Controlling Residual Drift in BRBFs by Combining SCCBFs in Parallel

Abstract

Buckling-restrained brace frames (BRBFs) exhibit well-controlled seismic demands due to their excellent energy dissipating capacity. However, excessive residual deformation is prone to accumulate in such framing systems after earthquakes. This poses a critical challenge to the postevent resilience and reparability. Self-centering concentrically braced frames (SCCBFs) are known for their outstanding capability to recover from large inelastic deformation. Therefore, combining SCCBFs in parallel suggests a promising strategy for BRBFs to reduce residual deformation demand. To this end, numerical studies are carried out to investigate the seismic control effect of SCCBFs for the BRBFs, particularly the influence on the residual deformation demand. This paper indicates that the BRBFs benefit remarkably from the engagement of SCCBFs by substantially reducing residual deformation. Furthermore, the combined frames exhibit residual deformation less than the out-of-plumb and reparability limits. In addition, parametric analyses of the hysteretic parameters of SCCBFs show that small values of both postyield stiffness ratio and energy-dissipation coefficient are more favorable from the perspective of control residual deformation.