МОДЕЛЮВАННЯ НЕСТАЦІОНАРНОГО ПРОГРІВУ ВОГНЕЗАХИЩЕНИХ ЗАЛІЗОБЕТОННИХ КОЛОН

Abstract

The analysis of the results of studies of the fire resistance of reinforced concrete structures was carried out and it was established that the existing approaches to the assessment of fire resistance do not always allow obtaining optimal solutions for the thermal engineering calculation of a fire-resistant reinforced concrete column. Creation of foundations for effective assessment of fire resistance of fire-resistant reinforced concrete building structures with scientifically based parameters of fire-resistant coatings is an urgent problem. Solving this problem will lead to an increase in the accuracy of thermal engineering calculation of fire-resistant reinforced concrete columns with the accuracy required for engineering calculations. In this regard, the authors developed a finite element model for simulating non-stationary heating of a fire-resistant reinforced concrete column. The model allows you to evaluate the fire resistance of both unprotected and fire-protected reinforced concrete columns, take into account the properties of the column material and the material of the fire-resistant coating. The evaluation algorithm includes the implementation of experimental and calculation procedures when determining the fire resistance of fire-resistant reinforced concrete columns. The authors modeled the non-stationary heating of a fire-resistant reinforced concrete column at the standard fire temperature regime using the developed model. The determination of the thermophysical characteristics of the fire-resistant coating when solving the problem of non-stationary thermal conductivity is a feature of modeling the non-stationary heating of a fire-resistant reinforced concrete column. When determining the effectiveness of the developed model, a comparison was made of the results of numerical modeling of the heating of a reinforced concrete column with the results of an experimental study of the fire resistance of a reinforced concrete column. The authors proposed modeling the fire protection of a reinforced concrete column to increase the fire resistance limits to the required values of the fire resistance limit. The adequacy of the developed model is confirmed by the satisfactory convergence of the experimental and calculated temperatures. The possibility of modeling non-stationary heating of fire-resistant reinforced concrete columns taking into account their initial and boundary conditions, geometry, material characteristics, concrete class, reinforcement class, thermophysical characteristics of fire-resistant coatings, test conditions and heating conditions is a feature of the developed finite element model.

Keywords: fire resistance, simulation of non-stationary heating, reinforced concrete column, fire protection, fireproof coating, LIRA-SAPR.