The influence of reinforcing joints on the fire resistance of reinforced concrete structures

This article analyzes the behavior of reinforcing joints when exposed to a fire load. The scientific work presents the results of an experiment on the fire resistance of reinforcing samples with coupling and welded joints. Experimental studies of cold and hot tensile samples were carried out. A test of loaded, heated and cooled rods was also performed, simulating the real effect of a fire on a loaded structure. During all three experiments, the values of the deformation and strength characteristics of the mechanical and welded joints of the bar reinforcement were compared. The experiment was verified in the Abaqus software package for the coupling connection in flexible reinforced concrete structures. Coefficients were derived that take into account the decrease in the strength of a reinforcing specimen with a sleeve connection depending on the heating temperature in the stressed state. Based on the data obtained using the studies, it can be concluded that the coupling and welded joints of the reinforcing bars give additional rigidity to the samples, without compromising the strength characteristics of the reinforcing bar. In the course of the experiments, the coupling and welded joints proved to be approximately the same, it should be noted that from the point of view of application efficiency, coupling joints have significant technological advantages compared to the welded joint.