Analysis of cooling rate impact on the behavior of steel and reinforced concrete beams under fire conditions

Abstract

This paper comprehensively investigates fire-induced structural degradation in reinforced concrete and steel beams, employing advanced thermal and mechanical analysis techniques. The study uses the finite element method and SAFIR software to conduct a sophisticated thermal analysis to assess structural performance quantitatively under complex fire scenarios. The research innovatively explores both the heating and cooling phases of fire events, revealing critical insights into material behaviour. The study provides a nuanced understanding of structural response mechanisms by adapting stress-strain curves to account for temperature-dependent variations and residual stresses. Specifically, the analysis employs parametric temperature curves from EN 1991-1-2 standard, enabling precise modelling of thermal loading conditions. A ground-breaking parametric study systematically evaluates cooling rate impacts on beam structural integrity. Key findings demonstrate that while accelerated cooling rates can initially enhance beam resistance, prolonged or non-uniform cooling phases may induce significant residual deformations and compromise structural stability. The research highlights the complex thermomechanical interactions within steel and reinforced concrete beams.