Journal of Computational Applied Mechanics

Influence of load-level and effective thickness on the fire resistance of composite slabs with steel deck

Document Type : Research Paper

Authors

1 Universidade Tecnológica Federal do Paraná, Curitiba, Brazil

2 Instituto Politécnico de Bragança, Bragança, Portugal

Abstract

Composite slabs with steel deck have been used on building construction due to its fast-and-easy crafting that brings economic outstanding alternatives to architects and engineers on large-scale steel framed constructions. At room temperatures and in Europe, the designing procedures of composite slabs are defined by Eurocode 1994-1-1. When it comes to the fire safety analysis of these elements, the designing procedure requires more attention due to the direct exposition of the steel deck to fire, affecting the overall bending resistance. This importance is presented in Eurocode 1994-1-2, taking in consideration the integrity, insulation and load-bearing criteria. In this work the thermal and mechanical behaviour of composite slabs with steel deck exposed to standard fire ISO 834 are studied through numerical simulations using Finite-Element Method (FEM). The model was previously validated with one experimental test from literature. The ANSYS Mechanical APDL software was used to develop a parametric study, simulating four different geometries with different load levels, comprehending a total of 126 thermal and mechanical simulations used to determine the correlation between load-level and fire resistance. As result, a new simplified method is proposed for the load bearing fire resistance of composite slabs, considering the effect of the effective thickness and the load level. The fire resistance decreases with the load level and increases with the thickness of the concrete. A new proposal is presented to determine the fire resistance, based on these two parameters.

Keywords

[1]           ECCS, Calculation of the Fire Resistance of Composite Concrete Slabs with Profiled Steel Sheet Exposed to the Standard Fire, Fire Safety of Steel Structures, European Convention for Constructional  Steelwork - Committee T3, 1983.
[2]           G. Thomson, C. K. Moxon, R. R. Preston, Indicative Fire Test on Composite Concrete/Steel Deck Floor System, Steel Construction Institute, Rotherham,  pp. 1987.
[3]           G. M. E. Cooke, R. M. Lawson, G. M. Newman, Fire resistance of composite deck slabs, The Structural Engineer, Vol. 66, No. 16, pp. 253–267, 1988.
[4]           R. Hamerlink, J. W. B. Stark, A numerical model for fire-exposed composite steel / concrete slabs, in Proceeding of, 115–130.
[5]           K. Both, Fire-exposed continuous span composite steel-concrete slabs, HERON, Vol. 41, No. 3, pp. 187-199, 1996.
[6]           CEN, EN 1994-1-2: Design of Composite Steel and Concrete Structures. Part 1-2: General Rules - Structural Fire Design, European Committee for Standardization, 2005.
[7]           L. Lim, C. Wade, Experimental Fire Tests of Two-Way Concrete Slabs,  722, University of Canterbury. Civil Engineering,  pp. 1992.
[8]           J. Jiang, A. Pintar, J. M. Weigand, J. A. Main, F. Sadek, Improved calculation method for insulation-based fire resistance of composite slabs, Fire Safety Journal, Vol. 105, pp. 144-153, 2019.
[9]           P. A. G. Piloto, C. Balsa, L. Prates, R. Rigobello, The air gap effect on the fire resistance of composite slab with steel deck, in Numerical Methods in Engineering – CMN, 2019, pp. 610–624.
[10]         P. A. G. Piloto, C. Balsa, F. Ribeiro, R. Rigobello, Computational Simulation of the Thermal Effects on Composite Slabs Under Fire Conditions, Mathematics in Computer Science, Vol. 15, No. 1, pp. 155-171, 2020.
[11]         P. A. G. Piloto, C. Balsa, L. M. C. Santos, É. F. A. Kimura, Effect of the load level on the resistance of composite slabs with steel decking under fire conditions, Journal of Fire Sciences, Vol. 38, No. 2, pp. 212-231, 2020.
[12]         R. Hamerlinck, The behaviour of fire-exposed composite steel/concrete slabs,  Thesis, Technische Universiteit Eindhoven, Eindhoven, 1991.
[13]         R. Hamerlinck, L. Twilt, Fire resistance of composite slabs, Journal of Constructional Steel Research, Vol. 33, No. 94, pp. 71–85, 1995.
[14]         P. A. G. Piloto, C. Balsa, F. Ribeiro, L. Santos, R. Rigobello, É. Kimura, Three-Dimensional Numerical Modelling of Fire Exposed Composite Slabs with Steel Deck, MATTER: International Journal of Science and Technology, Vol. 5, No. 2, pp. 48-67, 2019.
[15]         CEN, EN 1363-1: Fire resistance tests Part 1: General Requirements, CEN - European Committee for Standardization, 2004.
[16]         CEN, EN 1363-1: Fire resistance tests Part 1 : General Requirements, CEN-Europ, European Committee for Standardization, 2020.
[17]         CEN, EN 13501-2 Fire classification of construction products and building elements, European Committee for Standardization, 2009.
[18]         CEN, EN 1991-1-2, Eurocode 1: Actions on structures – Part 1-2: General actions – Actions on structures exposed to fire, European Committee for Standardization, 2002.
[19]         CEN, EN 1993-1-2: Design of steel structures - Part 1-2: General rules - Structural fire design Eurocode, European Committee for Standardization, 2005.
[20]         G.-Q. Li, N. Zhang, J. Jiang, Experimental investigation on thermal and mechanical behaviour of composite floors exposed to standard fire, Fire Safety Journal, Vol. 89, pp. 63-76, 2017.
[21]         J. Jiang, J. A. Main, J. M. Weigand, F. H. Sadek, Thermal performance of composite slabs with profiled steel decking exposed to fire effects, Fire Safety Journal, Vol. 95, pp. 25-41, 2018.
[22]         ISO, ISO 834-1 Fire-resistance tests - Elements of building construction, International Standard Oganization, 1999.
[23]         Y. A. Çengel, A. J. Ghajar, 2015, Heat and Mass Transfer: Fundamentals and Applications, McGraw-Hill, New York, 5ed.
Journal of Computational Applied Mechanics
Volume 52, Issue 2
June 2021
Pages 193-205
  • Receive Date: 27 December 2020
  • Revise Date: 27 January 2021
  • Accept Date: 28 January 2021