Research On New Type Of Assembled Beam-column Energy Consumption Connection Joints

The beam-column joint is regarded as the transmission link of assembled frame structure whose transmission properties and integrity play an important role in safety of buildings.At present,the connection forms of assembled beam-column joint include dry connection and wet connection.By combining advantages and disadvantages of dry connection and wet connection,this paper presents a new type of beam-column joint,realizing connection through high-strength bolts and bushes.This type of joint combines the advantages of dry connection and wet connection,which can not only avoid poor connection effects of dry joints and ductility,but can also overcome complex construction and pollution problems of wet joints.The working performance and mechanical characteristics of this type of joint are studied.The major contents are as follows.(1)A new type of beam-column joint is designed according to Seismic Design Principles.The dimensions,materials,connection forms and other parameters of specimens are determined.Three full scale frame side joints(PC1,PC2,PC3)were designed and fabricated on the basis of Construction Code,whose connection positions away from the edge of column were different.(2)In order to study deeply seismic performance of this kind of joint,the whole loading process and failure modes of three specimens with different connection locations under low cycle loading were discussed.And the hysteretic curves,skeleton curves,stiffness degradation and energy dissipation capacity were also analyzed.The test results show that this type of joint could control plastic hinge position to protect joint core area and could meet the demand of seismic design code.The bolts could perform very well and provide perfect friction force and tight force.But there were some problems in the longitudinal reinforcement connection of both sides.Because the reserved width of cast-in-place area was too small,the welding construction was difficult,resulting that welding strength could not be guaranteed and longitudinal bars of the joint failed quickly during the loading test.(3)The models are established by finite element software-ABAQUS to compare the hysteretic curves and skeleton curves of models and specimens.The analysis results by finite element software could coincide with tests results before cracking.With the displacement increasing,the difference was obvious significantly,and the hysteretic curve obtained by simulation was more full than that obtained by experiment on the whole.(4)The improved joint is designed according to test results and simulation results.And the improved joint is analyzed by ABAQUS to compare performance of joints.The results show that the hysteretic curves of the improved joints were fuller than those of the original ones,and the bearing capacity and energy dissipation capacity of the joints were obviously improved.By comparing the three improved joints,it is found that when the distance from the joint to the end of the beam exceeded the certain range,the joint location had little effect on the joint performance.