Evaluation of fire resistance of steel building structures taking into account the influence of heat exchange with adjacent structures

Abstract

Purpose. On the basis of experimental studies and theoretical data, to determine the thermophysical characteristics of an intumescent fire retardant and evaluate the heating of steel structures with intumescent fire protection of the outer surface, taking into account the adjoining of a concrete coating, as well evaluate the effect of heat transfer with a concrete coating on the optimal layer thickness of an intumescent fire retardant to ensure the required fire resistance limit.

Methods. Modeling in the system of finite element analysis.

Findings. On the basis of a series of experimental and theoretical studies in the ANSYS finite element analysis system, the thermotechnical problem of fire resistance of steel structures with fire protection of the outer surface based on an intumescent composition was solved, taking into account the abutment of a concrete coating. Experimental studies are used to assess the effective values of the thermophysical characteristics of an intumescent composition by solving the inverse problem of thermal conductivity for a computational finite element model using parametric optimization methods. The obtained thermophysical characteristics made it possible to evaluate the heating of steel structures with fire protection, taking into account heat transfer with a concrete coating. Depending on the required fire resistance level and the type of the considered structures (floor slab) and the design situation, taking into account heat exchange with the concrete coating, the optimal thickness of the fire retardant coating that provides the required fire resistance level is reduced by 1.2 ... 4.4 times.

Application field of research. The results can be used to solve the fire resistance problems of steel structures with partial and full fire protection of the outer surface during the design and construction of buildings and structures.