Vol. 10, No. 3, pp. 274-288 (2014)
SIDESWAY MAGNIFICATION FACTORS FOR STEEL MOMENT FRAMES WITH
VARIOUS TYPES OF COLUMN BASES
J. Kent Hsiao
Associate Professor, Department of Civil and Environmental Engineering,
Southern Illinois University Carbondale, Carbondale, IL, USA
E-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.
Received: 26 June 2012; Revised: 12 July 2013; Accepted: 17 July 2013
DOI:10.18057/IJASC.2014.10.3.2
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ABSTRACT:
The sidesway magnification factor was introduced to the design of columns in moment frames subjected to the P-Δ effect. Three approaches for the computation of the sidesway magnification factor, namely, the column-lateral-buckling-strength approach, the story-lateral-stiffness approach, and the modified-story-lateral-stiffness approach, were suggested by the 2005 AISC Specification for Structural Steel Buildings, the ASCE/SEI 7-10 Minimum Design Loads for Buildings and Other Structures, and the 2010 AISC Specification for Structural Steel Buildings, respectively. This paper evaluates the sidesway magnification factors derived from the aforementioned three approaches for four different column base conditions, namely, ideal fixed-, ideal pinned-, practical fixed-, and practical pinned-base conditions. The results of the study conducted in this paper are that (1) if only the flexural deflections are considered in the frame analysis, the sidesway magnification factor derived from the modified story-lateral-stiffness approach closely agrees with that derived from the column-lateral-buckling-strength approach and (2) if the flexural deflections, as well as the shear and axial deformations, are considered in the frame analysis, the sidesway magnification factor derived from the story-lateral-stiffness approach closely agrees with that derived from the column-lateral-buckling-strength approach.
KEYWORDS:
Deflection, Effective length, Lateral forces, Sidesway, Steel columns, Steel frames
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