EXPERIMENT STUDY ON SHEAR PROPERTIES OF RC BEAMS UNDER HIGH TEMPERATURE

Eight full-scale reinforced concrete (RC) beams were tested for fire resistance. The effect of boundary conditions, shear span to effective depth ratios, stirrup spacings on shear properties of beams at high temperature was analyzed. The thermal fields within beams, variations of temperature of reinforcing bars, vertical and horizontal displacement and crack developing modes of beams were studied. The fire resistance of RC beams with different parameters was compared. The results showed that the shear span to effective depth ratios had significant influence on shear properties of beams at high temperature, with shear span to effective depth ratios decreased, the fire resistance of beams was improved, however, the failure characteristics of beams were obviously brittle. With stirrup spacings of beams increased, fire resistance of beams was decreased in fire. Different from at room temperature, fire resistance of simply supported beams was better than that of restrained beams, due to internal force redistribution of beams at high temperature.