Optimal Placement for Buckling-Restrained Braces in Super Tall Building Structures Based on Grid Shear Deformation

摘要

Buckling-restrained braces (BRBs) dissipate dynamic energy by plastic metallic axial deformation.The energy dissipation capacity depends on the amplitude of axial deformation of the BRBs. Thenumber of BRBs in certain project is commonly limited due to budget constraint. It is alwaysdesirable that the BRBs are to be installed in those places which can maximize the energydissipation during earthquake. For super tall buildings, it is common practices that the BRBs are tobe installed in those stories which large story drifts. The storey drift of certain floor is composed oftwo kinds of deformation, say the rigid body displacement and racking (shear) deformation. Thispaper proposes to use grid shear deformation (GSD) of each floor for the optimal placement ofBRBs due to the fact that only shear deformation will induce energy dissipation. An optimalplacement method was developed based on GSD in this study. A super tall building with belt trussframe core-wall structural system is exemplified to show the effectiveness of the proposed GSDbased optimal BRBs optimal placement method. The results show that the optimal BRB placementsobtained by the proposed GSD method match well with the theoretically best placements which canmaximize the energy dissipation. The proposed GSD method can be generally applied for theoptimal placement of BRBs in super tall buildings.