Practical Recommendations for the Preliminary Design Analysis of Multi-Story Moment-Resisting Frames

Abstract

Approximate methods of analysis are essential tools at the preliminary
design phase of any building project. For multi-story multi-bay lateral-force-swayed frames, the available classical approximate methods are the Portal and the Cantilever techniques. It is known that the Portal method gives more accurate results for low to medium rise
frames. This investigation showed that it is possible to obtain more accurate analysis results than those availed by the Classical Portal method, if adequate account is taken of the essential factors that affect members' inflection points and the shear force resisted by the columns. The research method consisted of a study of frame behaviour through a detailed examination of the analysis results of ninety multistory fixed-feet sway frame variants analysed with the aid of computer software, SAP2000. Interior-to-exterior shear ratios for equal and unequal bay frames, as well as column inflection points were obtained
to serve as practical aids for preliminary analysis/design of fixed-feet multistory sway frames. Equal and unequal bay five story frames were analysed to show the validity of the recommended design parameters.

Keywords: Approximate, Preliminary Design, Portal Method, Sway Frames, Shear Ratio, Stiffness Ratio, Inflection Point.

African Research Review Vol. 2 (4) 2008: pp. 17-30