Experimental Study On Seismic Performance And Design Method Of New Prefabricated Column-to-column Connection Joints

Compared with the traditional column-to-column connection method in prefabricated buildings,this paper proposes a new prefabricated column-to-column connection joint that can be widely used in prefabricated mixed structures.It consists of three kinds of connection devices,including unbonded prestressed tendons,brass friction energy dissipators and angle steel.It has the characteristics of fast prefabricated,high seismic reliability,and good energy consumption performance.At present,there are few similar column-to-column connection joints at home and abroad,therefore,it is of great significance to study the seismic performance and design methods of new prefabricated column-to-column connection joints.This paper has completed low cyclic loading test researches on 5 new prefabricated column-to-column connection joints.The analysis focuses on the parameters such as different axial compression ratios,different angle steel thicknesses,and whether or not angle steels are arranged.The influences of these parameters on the seismic performance of specimens such as failure morphology,hysteresis curve,ductility and energy dissipation ability are analyzed.The specific content and conclusions are as follows:(1)The failure modes of the new prefabricated column-to-column connection joints under low cyclic loading are all fractures of the lower legs of the angle steel in the main force direction,and the upper ends of the lower column flanges are symmetrically deformed in the opposite direction of the half-wave buckling.The brass friction plate is severely worn,but the unbonded prestressed tendons are still in theelastic stage.The test specimen still has a strong load-bearing capacity and the column-to-column connection reliability is high.(2)The initial stiffness,ductility,energy dissipation capacity and buckling deformation of the upper end of the lower pillar flange increase with the increase of the axial compression ratio,and have a small effect on the bearing capacity.Increasing the thickness of the arranged angle steel can increase the bearing capacity of the specimen,slow down the stiffness degradation at the later stage of loading,and restrain the buckling deformation of the upper end of the lower column flange,but it will reduce the ductility of the specimen.The arrangement of angle steel can greatly increase the bearing capacity of specimens,exert the plastic energy consumption performance of the angle steel,and improve the energy consumption capacity of specimens.(3)The trilinear model is used in combination with theoretical analysis and mathematical fitting methods to determine the linear limit point,peak load point,and load limit point,formulate hysteresis rules.The restoring force model of new prefabricated column-to-column connection joints was proposed,and the agreement degree of the restoring force model was verified through comparative experiments and calculation of the skeleton curve.The restoring force model can provide a theoretical basis for the design of new prefabricated column-to-column connection joints.