| In the Northridge earthquake and Kobe earthquake,the traditional steel frame beamcolumn joints produced many brittle cracks.The results showed that weld crack has restricted the plasticity development of beam-column joints and cannot effectively dissipate the earthquake energy.In previous research,beams were all universal beam sections,which means beams were I-shapes with narrow flange.But sometimes,an I-shape beam with the narrow flange does not meet the design requirements;using the medium flange I-shape beam instead of it is a good choice.However,there are seldom reports on this type of beam-column connection.In order to further explore the mechanical properties under cyclic loading,the study carried on the ABAQUS finite element simulation of frame joints with mid-flange I-shape beam under cyclic loading.This paper studied the hysteretic behavior of cover-plate reinforced joint with strengthen-joint-region.We varied the joint’s finite element analysis parameters to study the joints’ failure mechanism and key factors to study the weld stress distribution,to study the matching between stiffness and ductility,and other issues.At the same time,this research also studied improvements aiming at the shortcoming of the joints.The works and conclusions are as follows:· It was proved that the ABAQUS finite element simulation method in this study has high accuracy and reliability through the simulation of the steel beam-column joint test.· Through cover-plate reinforced joints and the standard joints comparative analysis,it concluded that: bearing capacity,ductility factor,and plastic rotation capacity of coverplate reinforced joints were better than standard joints.· Specimens were divided into three groups according to steel beam size: the cross-section dimensions of HW350×350×12×19,the cross-section dimensions of HM390×300×10×16,and the cross-section dimensions of HM340×250×9×14.For all the three groups of specimens,HW502×470×20×25 column(with a height of 3600mm)and long span of the beams(3000 mm).The conclusions indicate that the beam has a wider flange and better ductility and deformation capacity.Moreover,the joint’s initial rotational stiffness significantly improved in the first group,and the rotational deformation of the joint reduced than the other two groups.· The results show that the shape of the cover plate has little effect on the joint stress distribution.The larger the cover plate’s length and thickness will improve the joint’s rotational stiffness,but it will cause the beam end’s plastic hinge to move outward and reduce its plastic rotational capacity.· The cover-plate length and thickness have an obvious impact on joints’ seismic performance.When the cover-plate length and thickness were taken at 0.5 times the beam flange section height and thickness,the joint has great stiffness and ductility. |
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