fire induced spalling

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Effect of Fire Induced Spalling on the Response of Reinforced Concrete Beams

Journal Title, Volume, Page: 
International Journal of Concrete Structures and Materials, Vol. 2, No. 2, pp. 71-81
Year of Publication: 
2008
Authors: 
Dwaikat M.B.
CEE Dept., Michigan State University, MI 48824, USA
Current Affiliation: 
Building Engineering Department, Faculty of Engineering and Information Technology, An-Najah National University, Nablus, Palestine
Kodur V.R.
CEE Dept., Michigan State University, MI 48824, USA
Preferred Abstract (Original): 

A macroscopic finite element model is applied to investigate the effect of fire induced spalling on the response of reinforced concrete (RC) beams. Spalling is accounted for in the model through pore pressure calculations in concrete. The principles of mechanics and thermodynamics are applied to compute the temperature induced pore pressure in the concrete structures as a function of fire exposure time. The computed pore pressure is checked against the temperature dependent tensile strength of concrete to determine the extent of spalling. Using the model, case studies are conducted to investigate the influence of concrete permeability, fire scenario and axial restraint on the fire induced spalling and also on the response of RC beams. Results from the analysis indicate that the fire induced spalling, fire scenario, and axial restraint have significant influence on the fire response of RC beams. It is also shown that concrete permeability has substantial effect on the fire induced spalling and thus on the fire response of concrete beams. The fire resistance of high strength concrete beams can be lower that that of normal strength concrete beams due to fire induced spalling resulting from low permeability in high strength concrete.  

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Fire Induced Spalling in High Strength Concrete Beams

Journal Title, Volume, Page: 
Fire Technology, Volume 46, Issue 1, pp 251-274
Year of Publication: 
2010
Authors: 
M. B. Dwaikat
Department of CEE, Michigan State University, East Lansing, MI, USA
Current Affiliation: 
Building Engineering Department, Faculty of Engineering and Information Technology, An-Najah National University, Nablus, Palestine
V. K. R. Kodur
Department of CEE, Michigan State University, East Lansing, MI, USA
Preferred Abstract (Original): 

A macroscopic finite element model is extended to account for fire induced spalling in high strength concrete (HSC) beams. The model is based on the principles of mechanics and thermodynamics and utilizes pore pressure calculations to predict fire induced spalling in concrete. For validating the model, spalling measurements were made by conducting fire resistance experiments on four normal strength and high strength concrete beams. Spalling predictions from the model are compared with the measured values of spalling at various stages of fire exposure. The validated model is applied to investigate the influence of fire scenario, concrete strength (permeability) and axial restraint on the fire induced spalling and fire response of RC beams. Results from the analysis show that fire scenario, and concrete permeability largely influence the extent of fire induced spalling in concrete beams. Further, it is also shown that the extent of spalling has significant influence on the fire resistance of RC beams.

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