Experimental And Finite Element Analysis Research On Seismic Behavior Of The Connections Between The Square Steel Pipe Column And Circular Steel Pipe Column In Imitated Ancient Building

As ancient Chinese architecture, imitated ancient buildings are so graceful in shape,grand and magnificent. They have been widely used in engineering structures in recent years. Column is the key part of imitated ancient buildings and its appearance is consistent with that of traditional ancient building column. The cross section of the upper portion and lower portion in the connection of the column is different. So the structure and the transferring way of inner force of the connections between the square steel pipe column and circular steel pipe column in imitated ancient building are quite different from the conventional joints, and lack of theory and experimental study.However, there are few design standards for the imitated ancient building.In order to study the failure modes and seismic behavior of the connections between the square steel pipe column and circular steel pipe column in imitated ancient building, four 1/1.5-scale specimens were designed and tested under constant vertical load and low cyclic reversed load. The failure process and patterns were observed, the load-displacement hysteretic loops and skeleton curves were obtained. The effects of specimen types and axial compression ratio on the failure mode, hysteretic performance,stiffness, bearing capacity, ductility and energy dissipation capacity were analyzed. The results show that connections damage at the welds near the root of the flange of the square steel pipe column. The hysteretic loops of the connections are in a plump-shape.The connections have insignificant stiffness degradation and high bearing capacity. As the connections failed,the ductility factor of the story drift is between 4.17 and 4.97 and the equivalent viscous damping coefficient is about 0.445 to 0.537, showing excellent energy dissipation capacity and seismic behavior.Then non-linear finite element study about the steel structure of connections with software ABAQUS based on the experimental study was carried out, the results show that numerical results were in accordance with test results. Parametric studies of the connections were carried out based on the numerical model. The axial compression ratio,steel strength and width-to-thickness of wall in the square steel pipe column were all considered as analysis parameters, influential laws of bearing capacity, rigidity and ductility were obtained. The results show that the horizontal bearing capacity and stiffness of specimen reduce with the increasing of the axial compression ratio, while the ductility increase instead, in certain extent; the horizontal bearing capacity and stiffness of specimen increase with the increasing of steel strength, while the ductility reduce instead; the effects of the width-to-thickness of wall in the square steel pipe column on horizontal bearing capacity, stiffness and ductility of specimen are similar to that of the axial compression ratio.The research results will provide reference for the seismic design and practical application of steel imitated ancient column with connections between the square steel pipe column and circular steel pipe column.