Evaluation of fire resistance of reinforced concrete beams on the basis of use of parametric temperature curves of fire modes

Abstract

The article considers the calculation method for assessing the fire resistance of reinforced concrete beams under the condition of parametric temperature regime of the fire. Temperature analysis for both parametric and standard fire exposure was performed and the corresponding plastic moments depending on the duration of the fire were determined. On the basis of the conducted research the diagrams of limiting moments for reinforced concrete beams are constructed. These diagrams allow you to check the strength conditions and assess the affiliation of reinforced concrete beams to the appropriate standard class of fire resistance. Using the constructed graphs of dependences of limiting plastic moments on the value of fire duration corresponding to standard classes of fire resistance for reinforced concrete beam, it is concluded that the standard temperature of fire is the most severe and leads to a constant reduction of limiting moment in contrast to others with horizontal branches, due to the descending branch of the calculated temperature of the fire according to the parameters of the room. On average, when using the temperature regimes of fire, determined by the proposed mathematical models, the limiting plastic moments are three times less than the limiting plastic moments determined under the influence of the standard temperature of the fire.