Publicação
Experimental and numerical research on the critical temperature of laterally unrestrained steel I beams
| Resumo: | Lateral unrestrained steel beams when subjected to high temperatures may collapse in service by lateral torsional buckling. This instability state may be predicted in the resistance, temperature and time domain. In this work the beam strength is determined in the temperature domain from a batch of numerical and experimental tests, with a specified degree of utilisation and a typical accident temperature rise. The experimental set-up is a reaction portal frame especially designed for beam elements under elevated temperatures. The specimens were heated by means of electroceramic resistances and a fibre mat specimen cover is used to increase the thermal efficiency. The material and the beam initial state conditions were considered, the experimental procedure being based on constant mechanical action under increasing thermal load. The experimental data was compared with numerical solutions, obtained from a geometric and material nonlinear analysis. A shell finite element modelling, with incremental and iterative procedures, was used in the numerical calculations. Good agreement was obtained between experimental and numerical data. However, both numerical and experimental results lead to higher critical temperatures when compared with the simplified calculation procedure presented in Eurocode for this case. |
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| Autores principais: | Mesquita, L.M.R. |
| Outros Autores: | Piloto, P.A.G.; Vaz, M.A.P.; Vila Real, Paulo M.M. |
| Assunto: | Steel beams Fire resistance Lateral buckling Critical temperature Experimental tests Numerical analysis |
| Ano: | 2005 |
| País: | Portugal |
| Tipo de documento: | artigo |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Instituto Politécnico de Bragança |
| Idioma: | inglês |
| Origem: | Biblioteca Digital do IPB |
| Resumo: | Lateral unrestrained steel beams when subjected to high temperatures may collapse in service by lateral torsional buckling. This instability state may be predicted in the resistance, temperature and time domain. In this work the beam strength is determined in the temperature domain from a batch of numerical and experimental tests, with a specified degree of utilisation and a typical accident temperature rise. The experimental set-up is a reaction portal frame especially designed for beam elements under elevated temperatures. The specimens were heated by means of electroceramic resistances and a fibre mat specimen cover is used to increase the thermal efficiency. The material and the beam initial state conditions were considered, the experimental procedure being based on constant mechanical action under increasing thermal load. The experimental data was compared with numerical solutions, obtained from a geometric and material nonlinear analysis. A shell finite element modelling, with incremental and iterative procedures, was used in the numerical calculations. Good agreement was obtained between experimental and numerical data. However, both numerical and experimental results lead to higher critical temperatures when compared with the simplified calculation procedure presented in Eurocode for this case. |
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