Experimental investigation of the behaviour of a steel sub-frame under a natural fire

  • Santiago, Aldina (ISISE - Department of Civil Engineering, University of Coimbra) ;
  • Simoes da Silva, Luis (ISISE - Department of Civil Engineering, University of Coimbra) ;
  • Vaz, Gilberto (Department of Mechanical Engineering, ISEC - Polytechnic Institute of Coimbra) ;
  • Vila Real, Paulo (LABEST - Department of Civil Engineering, University of Aveiro) ;
  • Lopes, Antonio Gameiro (Department of Mechanical Engineering, University of Coimbra)
  • Received : 2008.12.01
  • Published : 2008.06.25


This paper details a testing facility ("NATURAL FIRE FACILITY") that allows closely-controlled experimental testing on full-scale sub-frames while reproducing the spatially transient temperature conditions measured in real fires. Using this test facility, an experimental investigation of six steel sub-frames under a natural fire was carried out at the Department of Civil Engineering of the University of Coimbra. The main objective of these tests was to provide insight into the influence of these connection types on the behaviour of steel sub-structures under fire. The experimental layout is defined by two thermally insulated HEA300 columns and an unprotected IPE300 beam with 5.7 m span, supporting a composite concrete slab. Beam-to-column connections are representative of the most common joint type used on buildings: welded joints and extended, flush and partial depth plate. Finally, the available results are presented and discussed: evolution of the steel temperature; development of displacements and local deformations and failure modes on the joints zone.


structural engineering;steel and composite structures;fire behaviour;full-scale tests;structural integrity


  1. Leston-Jones, L.C., Burgess, I.W., Lennon, T., Plank, R.J., "Elevated-temperature moment-rotation tests on steelwork connections", Proc. Instn Civil Engrs, Structures & Buildings, 122, pp. 410-419, 1997.
  2. Liu, T.C.H., Fahad, M.K. and Davies, J.M., "Experimental investigation of behaviour of axial restrained steel beams in fire", J. Constr. Steel Res., 58, 1211-1230, 2002.
  3. Santiago, A., Simoes da Silva, L. and Vila Real, P., "Effect of cooling on the behaviour of a steel beam under fire loading including the end joint response", Proceedings of 9th International Conference on Civil and Structural Engineering Computing, Egmond-aan-Zee, Nederlands, September 2-4, 2003.
  4. Simões da Silva, L., Santiago, A. and Vila Real, P. "A component model for the behaviour of steel joint at elevated temperatures", J. Constr. Steel Res. 57(11), pp. 1169-1195, 2002.
  5. Simões da Silva, L. Santiago, A., Vila Real, P. and Moore, D.B., "Behaviour of steel joints under fire loading", Steel Compos. Struct. 6, 485-513, 2005.
  6. Trinks W., Mawhinney, M.H., Shannon, R.A., Reed, R.J and Garvey, J.R., Industrial Furnaces, 6th edition, John Wiley & Sons, Inc., 2004.
  7. Wald, F, Simões da Silva, L., Moore, D., Lennon, T., Chladna, M., Santiago, A., Benes, M., and Borges, L., "Experimental behaviour of a steel structure under natural fire", Fire Safety J., 41(7), pp. 509-522, 2006.
  8. Wang, Y.C., Steel & Comp. Struct - behaviour and design for fire safety, Spon Press, London, 2002.
  9. Vila real, P.M.M., Piloto, P.A.G. and Franssen, J.-M.; "A new proposal of a simple model for lateral-torsional buckling of unrestrained steel i-beams in case of fire: experimental and numerical validation". J. Constr. Steel Res., 59(2), 179-199, 2003.
  10. ECSC project 7210, 2000 "Natural fire safety concept. Full Scale tests, Implementation in the Eurocodes and Development of an User-friendly Design Tool". ECSC project 7210-PA/PB/PC/PD/PE/PF/PR-060, 1997-2000.

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