Investigation of the Behavior of Steel I-Beams with Mineral Wool Fire Insulation Cladding during Fire Exposure

Abstract

The paper explores the mechanisms of integrity failure of fire insulating cladding made of mineral wool materials applied to a steel I-beam. A model of the structure was developed in the LS-DYNA software package, taking into account the dead weight of the element, the applied mechanical load, and the temperature effect of a fire simulated in accordance with the standard fire temperature regime. The software calculation data make it possible to take into account the thermal insulation effect of mineral wool cladding and the peculiarities of contact interaction between the elements of the system under the action of a standard fire temperature regime. The simulation results showed that under the influence of high fire temperatures, the fire-resistant cladding loses its integrity much earlier than the limit state of the load-bearing capacity of the steel beam is reached.The conditions under which delamination and reduction in the effectiveness of the thermal insulation cladding occur are analyzed. The calculation model assumes that the destruction of mineral wool material near the adhesive joint is cohesive in nature, due to the greater tension of the mineral wool fibers near the adhesive joint, and that the tensile and shear strength of the mineral wool itself is lower than that of the adhesive joint. This assumption is implemented through the corresponding contact interaction parameters in the model.