STUDY ON CRACK RESISTANCE OF BEAM-COLUMN JOINTS IN REINFORCED CONCRETE FRAME STRUCTURES

Ten specimens of interior joints with different depth beams were tested under reversed cyclic loadings. The experimental study was conducted by focusing on the influence of joint core dimensions and axial compression ratio on crack resistance of interior joints. Test results indicate that the column axial load fluctuates from time to time because of the unbalanced force occurred in the beam-column subassemblage due to the significant difference on stiffness between the deeper beam and the shallow beam. Based on the test results, a theoretical expression of influencing factors α was put forward. Furthermore, a theoretical formula of crack resistance capacity of beam-column joints (including ordinary interior joints, exterior joints, wide flat beam-column joints and joints with different depth beams) was proposed in this study. The formula was verified using 108 test data of 97 beam-column joints at home and abroad. The good agreement between the experimental results and prediction results of suggested formula is achieved.