Seismically Isolated Prefabricated Assembled Frame Column Connection Node Force Performance Analysis

At present,China’s construction industry is developing rapidly.The prefabricated assembly structure meets the demand of modern construction with short construction period,high economic efficiency and less pollution in the surrounding environment,etc.However,compared with cast-in-place specimens,prefabricated structures have poor continuity at the joints,and the nodal connection problem is the key problem of prefabricated structures,which affects the integrity and seismic performance of the whole structure,and to a certain extent restricts the development and application of prefabricated structures.The seismic isolation bearing can attenuate the seismic response of the superstructure,thus promoting the use of assembled structures in high-intensity zones.Based on this,this paper presents a systematic study on the connection method of seismic isolation nodes of prefabricated concrete frame columns at home and abroad,and proposes a connection method of seismic isolation nodes of prefabricated assemblies,and investigates the damage mode,hysteresis characteristics,energy dissipation capacity and overall node performance of prefabricated assembled seismic isolation nodes by combining low circumferential reciprocal test and finite element simulation.performance and other seismic performance.The main work contents are as follows:(1)Two prefabricated seismic isolation node specimens and one cast-in-place seismic isolation node specimen were designed and fabricated,and the geometric structure,reinforcement and fabrication process of each node specimen were introduced in detail,and the low circumferential repeated load tests were conducted,and the prefabricated assembled seismic isolation nodes could meet the requirements of connection performance,and the prefabricated assembled seismic isolation nodes had good seismic performance.(2)The strain and displacement measurements were used to examine the strain of concrete and reinforcement and the slip of the interface between the old and new concrete.The analysis results show that the concrete strain of the prefabricated assembly node is smaller compared with the strain at the bottom of the prefabricated column,and the maximum concrete strain is located at the bottom of the prefabricated column;the node cross area column and tenon concrete combined with grouting sleeve transfer can effectively form a shear mechanism to provide shear bearing capacity together,and the concrete is not damaged in the node area,which indicates that the new prefabricated assembly seismic isolation node transfer is clear,and the proposed formula for the shear bearing capacity of the prefabricated assembly seismic isolation node is proposed.The proposed formula of shear load capacity of prefabricated assembled nodes is basically in good agreement by comparing with the test value.(3)Based on the ABAQUS finite element analysis software,the numerical simulation of the prefabricated assembled seismic isolation nodes is carried out,and the interaction between the bonding of the old and new concrete surfaces,grouting sleeves and reinforcement and concrete is reasonably considered.(4)Based on the ABAQUS finite element analysis software,the effects on the seismic performance of the prefabricated seismic isolation nodes were analyzed by varying the diameter of the seismic isolation bearing and different axial pressure ratios based on the verification of the accuracy and reliability of the model.The analysis results showed that the seismic performance of the prefabricated isolated nodes was more influenced by changing the diameter of the isolation bearing than changing the axial pressure ratio,but the stiffness and ductility of the specimen decreased faster by increasing the axial pressure ratio.