Concrete filled steel tube (CFT) columns have been widely used in moment resisting frame structures both in seismic zones. This paper discusses the design of such members based on the advanced methods introduced in the 2005 AISC Specification and the 2005 Seismic Provisions. This study focuses particularly on design following both linear and nonlinear methods utilizing equivalent static and dynamic loads for low-rise moment frames. The paper begins with an examination of the significance of pseudo-elastic design interaction equations and the plastic ductility demand ratios due to combined axial compressive force and bending moment in CFT members. Based on advanced computational simulations for a series of five-story composite moment frames, this paper then investigates both building performance and new techniques to evaluate building damage during a strong earthquake. It is shown that 2D equivalent static analyses can provide good design approximations to the force distributions in moment frames subjected to large inelastic lateral loads. Dynamic analyses utilizing strong ground motions generally produce higher strength ratios than those from equivalent static analyses, but on more localized basis. In addition, ductility ratios obtained from the nonlinear dynamic analysis are sufficient to detect which CFT columns undergo significant deformations.

• Park, Ji-Woong(Dept. of Civil and Environmental Engineering, University of Incheon, The Masters Course) | 박지웅
• Rhee, Doo-Jae(Daelim Industrial Co.Ltd. Duputy Department Head) | 이두재
• Chang, Suong-Su(CONFRA Co.Ltd. President) | 장성수
• Hu, Jong-Wan(Dept. of Civil and Environmental Engineering, University of Incheon) | 허종완 Corresponding author