EVALUATION OF DESIGN FIRE RESISTANCE OF A REINFORCED CONCRETE BEAM WITH CENTRAL PROP

Abstract

The article describes the essence of the technological method of testing a reinforced concrete beam with central prop for fire resistance without destruction, based on a set of individual indicators of the quality of concrete and reinforcement. The influence of the geometrical dimensions of a reinforced concrete beam with central prop, the heating pattern of the calculated cross section under fire conditions, the placement of the reinforcement in the calculated cross section, the depth and degree of fire protection of the concrete, the coefficient of thermal diffusion of concrete, the magnitude of the test load on the beam and the stress intensity in the bars of the longitudinal working reinforcement were investigated. The fire resistance limit of a beam with central prop is determined by the sign of loss of bearing capacity using the analytical equation (1). The use of the new proposed technological method allows to determine the actual fire resistance of a two-span reinforced concrete beam without full-scale fire impact, simplifies engineering calculations, increases the reliability of static material quality control and non-destructive testing, reduces economic costs.