OPTIMAL PLACEMENT METHOD OF OUTRIGGER WITH BRB IN A CORE WALL SYSTEM STRUCTURE

Abstract

The outrigger system has shown to be an effective structural lateral load resisting system in super-tall buildings and provides significant lateral stiffness under seismic loading conditions. The optimal placement of outrigger along with optimal combination of energy dissipation devices have major influence on seismic performance of super-tall buildings. In this paper, the power optimization procedure is performed to determine the optimal number and optimal location of outriggers by controlling Buckling Restrained Braces (BRBs) stiffness installed at perimeter column and outrigger connection zone. A 9-zone Finite Element (FE) model is developed in MATLAB programing and is subjected to a series of nonlinear time history analyses. The number of outrigger and BRB stiffness is considered as design variables, and the inter-story drift response of the model is to be minimized as objective functions. The results indicate that the optimization solution with different BRB grouping has almost the same solution and increasing of BRB stiffness does not significantly affect the optimal placement solution of outriggers. Therefore, this method of optimization solution shown to be an effective and practical optimal solution of optimal placement of outriggers with BRB for improving the seismic performance of outrigger system structure.