Multi-Objective Optimization for Performance-based Seismic Retrofit using Connection Upgrade

The unanticipated brittle fracture of connection of the steel moment resisting frame (SMRF) occurred in 1994 the Northridge earthquake. Since then, the researches for the vulnerability of connection of the existing SMRF and for rehabilitation of those buildings were conducted. This paper suggests performance-based optimal seismic retrofit technique using connection upgrade. For optimal design, a multi-objective genetic algorithm(NSGA-II) is used. One of the two objective functions is to minimize initial cost and another objective function is to minimize lifetime seismic damages cost. The optimal algorithm proposed in this paper is performed satisfying specified performance objective based on FEMA 356. The nonlinear static analysis is performed for structural seismic performance evaluation. A numerical example of SAC benchmark SMRF is provided using the performance-based optimal seismic retrofit technique proposed in this paper

Authors:

• Dong-Chul Lee
• Byung-Kwan Oh
• Se-Woon Choi
• Hyo-Sun Park

Keywords:

• connection upgrade
• performace-based seismicdesign
• seismic retrofit
• multi-objective optimization

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