SHEAR BEHAVIOUR OF INTERIOR JOINTS OF BEAMS WITH DIFFERENT DEPTH IN REINFORCED CONCRETE FRAMES

Six specimens of interior joints of beams with different depth were tested under reversed cyclic loadings. The failure characteristics and shear force versus shear angle skeleton curves of interior joints are analyzed. Based on the experimental study, an analytical model for equivalent joint core of an abnormal joint under the combined action of an axial load and a shear is established, and the shear stress versus shear angle curves of the equivalent joint core of tested specimens were calculated by using modified compression field theory (MCFT). Test results indicated that the first crack appeared in the minor core (determined by the low beam and the top column), and the final failure appeared in the large core (determined by the high beam and the bottom column). The critical crack load was quite nearly with the ultimate load of abnormal joints, and aseismic behavior of the beam-column joint sub-assemblage was poorer than that of ordinary joints. A good agreement between experimental results and prediction results is achieved.