Study On Seismic Behavior And Panel Zone Shear Deformation Effection Of Box Joint Region For Steel Frames With I-section Column

Box-joint region connection is a kind of post-northridge connections which was designed to put H-beam in the weak axis of I-section column(weak axis connection). It can be regarded as a sort of reinforced connection when it is used to put H-beam in the strong axis of I-section column(strong axis connection).The monotonic loading test of weak axis connection in fringe frame and finite element analysis of the same specimens under cyclic loading have preliminarily shown that the new connection has better seismic behavior. In order to further study the work effect of box joint region connection in steel frames with I-section columns, two full-scale steel frames connected respectively in I-section column strong axis and weak axis(new connection steel frame) were tested under cyclic loading to study the failure characteristic, hysteresis behavior, bearing capacity, stiffness, ductility and panel zone shear deformations influencing on storey drift. Then ANSYS has been used to simulate and analyze the specimens in the experiment to validate the correctness of the modeling method. Followed, 4 series of 40 finite element modeling were given to study the influence of axial compression ratio, post-northridge connection, stiffness ratio of beam to column, span, floor height and the number of spans and layers.The experimental results show that the box strengthened joint region connection belongs to the connection of ?strong joint region?. The new connection steel frame has better good bearing capacity, strong initial stiffness and good energy-dissipation capacity. When it failed, the plastic hinge occurred in the beam section away from the column face.The ductility factor is less than 3.0 owing to the fracture in the beams, which indicates that the ductility of new connection should be improved. The panel zone shear deformations influencing on storey drift should be neglected during the first stage of seismic design when it comes to connecting beam and column with box strengthen-joint region.The FEA results show that axial compression ratio should be controlled within 0.6. The new connection steel frame would keep ideal failure characteristic and good seismic performance when the the axial compression ratio is less than 0.6. Also, the function of the new connection can be achieved and storey drift caused by panel zone shear deformations is not obvious. Post-northridge connection can improve the seismic performance of new connection steel frame and make the plastic hinge in the beams away from the face of columns on condition that storey drift caused by panel zone shear deformations doesn?t augment. The stiffness ratio of beam to column increase is bad for the function of the new connection steel frame so that it shoud be controlled under 1.0 according to this paper. The change of span, floor height and the number of spans and layers has no significant effect on the storey drift caused by panel zone shear deformations. However, the increase of span can improve the seismic performance of new connection steel frame obviously and the floor height increasing has the opposite effect.