Abstract
According to these high-rise buildings under construction in Korea in recent years, core walls and mega structural system were introduced as a optimal structural system with a certain scale and plane form, what need to be done included the structural characteristics of this kind of system and the accurate results, and what's more, the study of simple optimization methods should also be investigated. In this paper, models of mega structural system were determined, Approximation concept of Stiffness-Based Optimal Design Technique based on optimal design technique of preceding research and displacement sensitivity analysis were formalized, lateral drift constraint equation was created, rate of change response of structures with the changing of design parameters was determined. The possibility of optimal selection and cross section calculation of mega structural members can be known through those processes.