Numerical studies of cellular beams at elevated temperatures

Siamak Bake, C. G. Bailey

Research output: Chapter in Book/Conference proceedingConference contribution

Abstract

This paper presents an investigation of the structural performance of composite cellular beams at elevated temperatures. The numerical studies were conducted using nonlinear shell elements and took into account material and geometrical non-linearity, geometrical imperfections and, for composite beams, the behaviour of the steel sheeting, concrete, reinforcing mesh and shear connectors. A smeared crack approach was used for the concrete together with a fracture energy concept to estimate the tensile stress of the concrete. The comparison with available test results showed that the developed models can predict, to a very high accuracy, the failure load together with the modes of failure witnessed in tests comprising webpost buckling and a vierendeel mechanism. The validated models were used for parametric studies to investigate the importance of different parameters comprising various, load ratios, imperfections, end restraint and load types in the behaviour of symmetric and asymmetric cellular beams at elevated temperatures. Based on the studies carried out is this research, it was shown that web post buckling was the predominate mode of failure in all of the case studies conducted at elevated temperatures. Moreover, asymmetric cellular beams were proved to be considerably more sensitive and vulnerable to the load ratios as well as support conditions compared to symmetric beams, in fire conditions. Point loads as well as line loads were also applied to beam which proved that the behaviour of the beam did not notably change with the loading types. The internal forces, catenary action and interaction between the cellular beam and the end supports, are also presented and discussed for various restraints and loading types. By obtaining an understanding of the detailed internal stress distribution, simple design guidance for cellular beams under fire conditions can be developed.
Original languageEnglish
Title of host publication5th International Conference on Advances in Steel Structures, ICASS 2007|Int. Conf. Adv. Steel Struct., ICASS
Pages734-740
Number of pages6
Volume3
Publication statusPublished - 2007
Event5th International Conference on Advances in Steel Structures, ICASS 2007 - Singapore
Duration: 1 Jul 2007 → …

Conference

Conference5th International Conference on Advances in Steel Structures, ICASS 2007
CitySingapore
Period1/07/07 → …

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