Seismic Behavior Of PEC Column (Weak Axis)-Reduced-Section Steel Beam Composite Frame With End-Plate Connection

Nowadays,Moment Frame structure is one of the most popular structures in practical engineering.It can better meet the "strong column weak beam,strong shear weak bending and strong joint" seismic design principle by reasonable designing.Composite frame structure composed of steel and concrete not just combined with the advantages of concrete structure and steel structure,but the interaction effect was developed to improve the stability of steel and increase the restraint of concrete.PEC column is a new type composite member.At the moment,the related study of PEC column are mainly concentrated on members,connection between structure nodes and substructure between floors,and less on the whole structure.Taking a two-story and one bay test specimen of crimping PEC column(weak axis)—reduced-section steel beam composite frame with end plates and pretension high-strength penetrating bolts connection as the research subject to study its seismic performance.The research results will provide theoretical basis for the application of PEC column in practical engineering.Considering the ability of loading equipment in the school laboratory,a 1:2 scale specimen was made to test its hysteretic behavior under quasi-static cyclic lateral loading.In order to reveal the seismic mechanism of the structure,FE software ABAQUS was adopted to simulate its hysteretic behavior under quasi-static cyclic lateral loading.Contrasting the results of simulation and test to prove the feasibility of finite element simulation.Also,the influence of axial force was considered in the specimen and using the finite element software to analysis of the effect of axial force to composite frame structure.So,the seismic performance of the model can get more closer to the actual engineering.According to the research results,it is indicated that the bearing capacity of specimen is high and initial lateral-resisting stiffness is large,the difference of lateral resisting stiffness between first storey and second storey is affected by the structural damage process of the specimen,but it get smaller with loading increasing,finally,tend to equal stiffness distribution between first storey and second storey;The lateral force of the specimen was sustained by PEC columns evenly,the lateral displacement of the specimen is mainly provided by the shear deformation of the specimen,showing the shear deformation mode of the specimen;the energy-dissipation capacity is provided by steel yielding and concrete crushing at bottom of PEC column and yielding of reduced-section of steel beam,however,the total energy consumption is mainly provided by four nodes,it is evenly distributedalong the height of the specimen;all connection exhibited soundly partial self-centering function,energy-dissipation and rotation capacity for end-plate with pre-tension penetrating bolts and reduced-section steel beam;the final failure mode of the specimen is that the four reduced cross-sections of steel beam are fully yield to form plastic hinges,then,the steel is yield and the concrete is crushed at the bottom of the two PEC columns to form plastic hinges,so the specimen from the structure into a plastic mechanism.The seismic ductility of the specimen can be fully reflected by the interstory drift rotation and connection rotation,though the analysis,it is found that they both surpassed the inter-story drift limit for frame structure at maximum considered earthquake level,hence the specimen owns superior seismic performance;through the simulation analysis of axial force specimen,the second-order effect caused by axial force accelerated the yield process of the specimen,make the specimen yield more energy consumption.