Advanced Steel Construction

Vol. 6, No. 4, pp. 1019-1033 (2010)


ADVANCED ANALYSIS AND PERFORMANCE BASED EVALUATION OF CONCRTE FILLED TUBE (CFT) COLUMNS

 

Jong Wan Hu 1,*, Joonam Park 2, and Roberto T. Leon 3

1 Associate Research Fellow, Office of National R&D Investment Strategy and Analysis, Korea Institute of S&T Evaluation and Planning (KISTEP), Seoul, 137-130, South-Korea

2 Senior Researcher, Korea Railroad Research Institute, Ui-Wang City, Kyung-gi, 437-757, South-Korea

3 Professor, School of Civil and Environmental Engineering, Georgia Institute of Technology, Atlanta, GA, 30332, USA

*(Corresponding author: E-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.; fax number: +82-2-589-2191)

 

Received: 5 July 2010; Revised: 6 August 2010; Accepted: 23 August 2010

DOI:10.18057/IJASC.2010.6.4.6

 

ABSTRACT:

This paper discusses the design of such composite structures which are based on the advanced methods introduced in the 2005 AISC Specification and the 2005 Seismic Provisions. The 2005 AISC specification explicitly allows the use of the full plastic capacities of concrete-filled tube (CFT) columns for members with slender steel walls and provides substantially larger bending capacities than previous specifications. This study focuses particularly on seismic design following the nonlinear method. The paper begins with an examination of pseudo-elastic design interaction equations and the ductility demand ratios due to combined axial compressive force and bending moment in CFT members. Based on advanced computational simulations for a series of low-rise composite-moment frames, this paper then investigates both building performance and new techniques in an effort to evaluate building damage during a strong earthquake. It is shown that 2 dimensional (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. Finally, ductility ratios obtained from nonlinear dynamic analyses are also sufficient to detect which CFT columns undergo significant deformations.

 

Keywords:CFT columns; Interaction ratio; Dynamic loads; Ductility; Composite-moment frames; Frame Analyses

 

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