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Paper 69

Structural Optimization of Tall Buildings using NSGA-II and Resizing Techniques

E.-M. Kwon, S.-W. Choi and H.-S. Park
Department of Architecture Engineering, Yonsei University, Seoul, Korea

Keywords: NSGA-II, resizing technique, structural optimization, tall building.

full paper (pdf) - reference

High-rise buildings must be structurally designed by repeatedly using the process of structural analysis to select member sections that satisfy the strength and stiffness requirements. In the case of strength design, the performance of the cross-section can be obtained by repeated structural analysis to ensure the strength of the members. Therefore, it is possible to control excessive local damage and deflection, vibration by resizing the members. But, the structural design can be controlled more effectively through optimal stiffness design to satisfy relative storey displacement, deflection for usability and for the satisfaction for building uses within the prescribed limits. Thus, in this paper optimal design is undertaken through stiffness design of a high-rise building.

The non-dominated sorted genetic algorithm (NSGA) is widely used in the field of multi-objective optimization. However issues such as the complexity of operation, the lack of sorting conditions and the difficulty of determining the shared variable value have been raised. Hence the NSGA-II algorithm [1] compensates for these shortcomings. Therefore in this paper NSGA-II is used for the multipurpose optimal design of high-rise buildings.

However, the effort for the structural analysis and calculations is greater and the rate of convergence is slower when using optimal design techniques because the number of the members and design variables becomes greater particularly in high-rise buildings [2]. Therefore, a major problem is to reduce the number of structural analyses for the optimal design of high-rise buildings. Hence in this study presented in this paper a resizing technique with the NSGA-II is used to improve the convergence speed. The results show that convergence speed and the number of structural analyses are reduced by approximately two-thirds.

References

1
K. Deb, A. Pratap, S. Agarwal, T. Meyarivan, "A fast and elitist multi objective genetic algorithm: NSGA-II", IEEE Trans. Evol. Comput., 6(2), 182-197, 2002.
2
H.S. Park, K.P. Hong, J.H. Seo, "Drift Design of Steel-Frame Shear-Wall Systems for Tall Buildings", Structural Design Tall Build., 11, 35-49, 2002.