Buckling length of a frame member
DOI:
https://doi.org/10.23998/rm.66836Keywords:
effective length, frame analysis, elastic bucklingAbstract
In steel frame design, the definition of buckling lengths of members is a basic task. Computers can be used to calculate the eigenmodes and corresponding eigenvalues for the frames and using these the buckling lengths of the members can be defined using Euler's equation. However, it is not always easy to say, which eigenmode should be used for the definition of the buckling length of a specific member. Conservatively, the lowest positive eigenvalue can be used for all members. In this paper, methods to define the buckling length of a specific member is presented. For this assessment, two ideas are considered. The first one uses geometric stiffness matrix locally and the other one uses strain energy measures to identify members taking part in a buckling mode. The behaviour of the methods is shown in several numerical examples. Both methods can be implemented into automated frame design, removing one big gap in the integrated design. This is essential when optimization of frames is considered.
References
Pierre Dumonteil. Simple equations for eective length factors. Eng J AISC, 29(3): 111-115, 1992.
EN 10219-2. Cold formed welded structural hollow sections of non-alloy and fine grain steels. Part 2: Tolerances, dimensions and sectional properties. CEN, 2006.
EN 1993-1-1. EN-1993-1-1. Eurocode 3: Design of steel structures. Part 1-1: General rules and rules for buildings. CEN, 2006.
EN 1993-1-8. EN-1993-1-8. Eurocode 3: Design of steel structures. Part 1-8: Design of joints. CEN, 2006.
Georgios E. Mageirou and Charis J. Gantes. Buckling strength of multi-story sway, non-sway and partially-sway frames with semi-rigid connections. Journal of Constructional Steel Research, 62(9):893 { 905, 2006. ISSN 0143-974X. doi:https://doi.org/10.1016/j.jcsr.2005.11.019.
G. R. Monforton and Tien Hsing Wu. Matrix analysis of semi-rigid connected frames. Journal of the Structural Division, 89:13{24, 1963.
R. Van Mellaert, K. Mela, T. Tiainen, M. Heinisuo, G. Lombaert, and M. Schevenels. Mixed-integer linear programming reformulation approach for global discrete sizing optimization of trussed steel portal frames. In Kai-Uwe Bletzinger, Sierk Fiebig, Kurt Maute, Axel Schumacher, and Thomas Vietor, editors, WCSMO-12, Germany, 2017. doi:https://doi.org/10.1007/978-3-319-67988-4 56.
A. Webber, J.J. Orr, P. Shepherd, and K. Crothers. The effective length of columns in multi-storey frames. Engineering Structures, 102:132{143, 2015. doi:https://doi.org/10.1016/j.engstruct.2015.07.039.
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Copyright (c) 2018 Teemu Tiainen, Markku Heinisuo
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