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Influence of Axial Restraint and Fire Exposure Scenarios on the Fire Resistance of One-Way Reinforced Concrete Slabs

Fidan Salihu, Anita Gjukaj, Guxim Rrudhani, Fatos Pllana, Meri Cvetkovska

Abstract


This study investigates the behavior of one-way simply supported reinforced concrete slabs under fire conditions, focusing on the effects of axial restraint and fire exposure scenarios on their fire resistance. The slabs are subjected to standard ISO 834 fire exposure, and the nonlinear analysis is carried out via the SAFIR2016 computer program, which employs the finite element method. A comparison of the numerical results with experimental results from various studies has shown good agreement. To verify the reliability of the numerical results, it is essential that the test parameters match those used in the simulations. This study aims to evaluate the accuracy and reliability of fire safety regulations for designing one-way simply supported slabs and to identify potential discrepancies between design codes and numerical findings. A 3D analysis is performed, with discretization using shell elements. The results reveal that axial restraint significantly influences the fire resistance of slabs. When axially restrained and exposed to fire from the bottom, the slab achieves fire resistance exceeding ten hours. However, under the same boundary conditions, the fire resistance of the slab is 339 minutes if the fire acts from the top. Without axial restraint, the direction of fire exposure becomes critical. When the fire acts from the bottom, the primary reinforcement is exposed to high temperatures, causing the slab to lose stability as the resisting moment decreases than the acting moment. Conversely, when the fire acts from the top, the slab without axial restraint shows high fire resistance, as the reinforcement remains in the cooler zone, leading to a fire resistance greater than ten hours.

 

Doi: 10.28991/CEJ-2025-011-04-03

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Keywords


One-Way RC Slab; Axial Restraint; Fire Scenario; Fire Resistance; 3D Analysis; SAFIR2016.

References


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Full Text: PDF

DOI: 10.28991/CEJ-2025-011-04-03

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Copyright (c) 2025 Fidan Hafez Salihu, Anita Mehmet Gjukaj, Guxim Mustafe Rrudhani, Fatos Emin Pllana, Meri Cvetkovska

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