Parametric Analysis Of Seismic Behavior Of Hybrid High Strength Steel Frames

Hybrid high strength steel frame is a new structural system with high strength steel columns(Q460,Q690 and Q890 etc.)and steel beams with low strength and strong deformation capacity(such as Q235 and Q345).It combines the advantages of high plastic deformation ability of low-strength steel and high strength steel,which could make the structural system satisfy the seismic design principle of "strong column and weak beam" of bending steel frame under strong earthquake effiently.In this paper,the finite element model of hybrid high-strength steel beam-column joints and frames is established by using the results of joint test research and frame test research at home and abroad.On the basis of verifying the reliability of the modeling method,the seismic performance of hybrid high-strength steel beam-column joints and hybrid high-strength steel frames are analyzed respectively.Finally,the method of combining beam element with shell element is used to establish the model of hybrid high-strength steel beam-column joints and hybrid high-strength steel frames.The multi-scale model of hybrid high-strength steel frame is established,and then the influence of shear deformation of each part of the frame on the performance of the frame is studied.The results show that: 1)the axial compression ratio of columns should not exceed 0.6 and should be less than 0.5,otherwise the seismic performance of hybrid high-strength steel beam-column joints will obviously deteriorate.2)the initial stiffness of hybrid high-strength steel beam-column joints will increase with the increase of the thickness of the joint area,and the stiffness degradation law is basically the same in the later period,and the deformation capacity will obviously improve.3)the story height has a certain influence on the seismic performance of hybrid high-strength steel frame.The higher the story height is,the worse the seismic performance of the structure will be.4)Increasing the beam span appropriately will increase the initial stiffness of the hybrid high-strength steel frame,which has little effect on the bearing capacity,ductility and energy dissipation capacity.5)The hybrid high-strength steel frame with Q460 steel strength grade combination has the best seismic performance.6)Different from the impact on the joints,increasing the thickness of the joint area appropriately,and the hybrid high-strength steel frame.The load-bearing capacity is obviously improved,and the stiffness degradation law is different in the later stage of the frame.7)Even if the beam-column component has a larger height-span ratio,the effect of shear deformation in the joint area on the seismic performance of the hybrid high-strength steel frame is more significant than that of the beam-column shear deformation,which can make the difference of initial stiffness up to 27%,and the difference of ductility and energy dissipation capacity of the frame structure is also very obvious.