Research On The Performance Of Frame-supported Short-leg Shearwall Structure With Haunched Transfer Beam Under Biaxially Cyclic Loadings

At present, the research on the seismic behavior of frame-leg supported short-shear wall haunched transfer beam structures are mainly restricted on single frame structure or local component node experimentally and numerically to understand the bearing capacity and load transfer mechanism of this kind of structure under cyclic loading. But little study, home and abroad, has been done towards the bidirectional horizontal loading on the integral structure of frame-supported short-leg shear wall haunched transfer beam. Therefore, the seismic behavior of the integrate structure and the response under cyclic loading could not be fully revealed. In this article, numerical simulation has been done, basing on the finite element analysis software ABAQUS, to study the seismic behavior of spatial integral structure by exerting vertical loading, horizontal unidirectional low cycle loading and horizontal bidirectional cyclic loading, respectively. The reliability and the accuracy of this study are verified by comparing with the previous experimental results. And further research have been done by using changing the parameters such as axial compression ratio, ratio of thickness and axillary angle to reveal the influence of these parameters on the seismic behavior of the integrate structure and the response under cyclic loading. This paper has mainly studied the destruction form, load-bearing capacity, hysteresis, skeleton curve and ductility coefficient under horizontal unidirectional low cycle loading and horizontal bidirectional cyclic loading in order to give reasonable suggestions and construction measures for structure design. The main conclusion obtained are as follows.(1)The improved frame-leg supported short- shear wall haunched transfer beam structures, which is subjected to the combined action of vertical load and horizontal unidirectional low cycle loading or horizontal bidirectional cyclic loading, have better seismic performance. This performance mainly contains of rational failure mechanism, gentle decreased degree skeleton curve, good ductility, energy dissipation capacity and well-proportioned stiffness distribution.(2)When the axial compression ratio is during 0.1~0.4, contrary to normal damage mechanism, the column hinge appears before the beam hinge and the lateral resistant of the structure becomes invalid due to that the concrete at the bottom of the column has been damaged seriously. Besides, when the axial compression ratio is about 0.55, the improved frame-leg supported short- shear wall haunched transfer beam structures has better seismic performance which contains of superior ultimate bearing capacity, larger displacement ductility coefficient and moderate stiffness degradation rate.(3) When the ratio of thickness is about 6, the comprehensive seismic performance is better. When the ratio of thickness is relatively larger, though the structure has higher bearing capacity, larger ductility coefficient and larger initial stiffness, the stiffness degradation rate increase rapidly after yield of the structure which is very bad for seismic performance. When the ratio of thickness is relatively smaller, even though there is no hinge appears in the beam, the concrete at the bottom of the column has been damaged seriously which is contrary to normal damage mechanism and is not conducive to seismic.(4)When the axillary angle is about 16°, the comprehensive seismic performance is better. When the axillary angle is 0°, the lateral stiffness and the failure load of the structure are all low. When the axillary angle is 30°, the concrete at the bottom of the column has been damaged seriously and is prior to the failure of the transfer beam.