Of all the design conditions for frames, in many cases the most critical one consists on ensuring that, under any possible combination of loads, flexural buckling should not take place, specially when the current trend is to design slender structures with high strength steels. Therefore, it is important to have a method to determine in a simple and clear way the maximum acceptable load level, usually known as the critical buckling load. With this purpose, we consider the equilibrium equations of each beam in its deformed configuration, under the hypothesis of infitesimal strains and displacements (First-Order Theory), resulting in a system of linear di®erential equations for each element. To obtain the nonlinear response of the frame, it is necessary to impose in each beam-end the compatibility of displacements and the equilibrium also in the deformed configuration. The objective of this work is to develop a systematic method to determine the critical buckling load and the buckling mode of any frame, without using the common simplifications usually assumed in matrix analysis or finite element approaches. This allow to obtain precise results regardless of the discretization done.
Published on 01/07/09
Accepted on 01/07/09
Submitted on 01/07/09
Volume 25, Issue 3, 2009
Licence: CC BY-NC-SA license
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