Результаты натурных огневых испытаний центрифугированных железобетонных колонн кольцевого сечения

Purpose. To evaluate the fire resistance of spun reinforced concrete columns of annular section under joint temperature and power load through full-scale experimental studies. Methods. Conducting full-scale fire tests of columns as a part of a fragment of a framed building. Visual observation of the behavior of the columns during the fire test. Temperature measurement of fire gaseous medium, reinforcement, concrete on the inner surface of columns, including in the place of the connection node with monolithic overlap. The measurement of the temperature and excess pressure of the gaseous medium in the hollow of the columns. Findings. Experimental dependences of changes in temperature of reinforcement and concrete on the inner surface of columns, including at the site of the node connection with monolithic overlap were obtained. The behavior of temperature and excess pressure change in the hollow of the columns is obtained. It was revealed that walls of spun reinforced concrete columns with free air hollow have higher rate of heating than the walls with monolithic concrete cotter in the hollow. The significant effect of increasing pressure of the gaseous medium in the hollow of the columns on their bearing capacity is not fixed. Explosive destruction of concrete of the columns during the fire tests is not fixed. The destruction of one of the columns during the fire tests occurred in the middle part of the height after the formation of main cracks, directed at an angle of 75–80° to the longitudinal axis of the construction, and increasing of bending deformation. The factual fire resistance limit of the experimental spun reinforced concrete columns of annular section with an eccentric applied load of 18.25 t was R60. Application field of research. The results of the study can be used to determine the thermophysical characteristics of spun concrete and to develop calculation model of fire resistance of spun reinforced concrete columns of annular section.