Experimental Study Of Earthquake Resistance And Bearing Capacity Analysis Of Abnormal Joints With Different Column Sections In Steel Frame Building

Abnormal joints studied in this thesis are untraditional ones with same beam sections and different section heights between the columns above and below the beam. Thus, web plate shape in the core zone of the node domain turns trapezoidal instead of rectangle one in the traditional condition. In China, test data and theoretical analysis are lacking for design recommendations of the joints in relevant drawing gallery.The prototype of the study is based on one of the joints of one high-rise steel residential building. Taking axial compression ratio and heights ratio of columns as parameters,6models scaled in1:2were made in a steel plant and conducted low-cyclic reversed loading test in structural lab. The study focuses on the hysteretic characteristics, bearing capacity, ductility performance, energy-dissipating capacity and the degradation law of strength and stiffness. The deformation mechanism and stress state of this kind of web were caught, and then the author did a computational formula derivation of shear capacity and a check formula derivation of strength of web plate. Computational results were compared with the test results, and they fit well.Test results show that abnormal joints with different column sections in steel frame building behave well in earthquake resistance, ductility performance and energy-dissipating capacity. Bearing capacity does not decline when all interlayer displacement angles are surpassing0.033rad. The primary failure mode in these cases is weld cracking in top flange of beam. Strength degradation coefficient is stable around0.95with minor strength degradation. So is the stiffness degradation rule. Besides, stiffness degradation rate in test specimen with axial compression ratio of0.4declines faster than the one with the ratio of0.2; energy coefficients goes around2.910to3.911when the specimens fail.