Dynamic Time History Analysis On Seismic Performance For Steel Frame With Modified Energy Consumption Nodes

Seismic design is actually the ductility design and good ductility can guarantee thebasic bearing capacity under severe earthquake. Nodes of anti-earthquake ductility iscrucial to the overall seismic capacity of the frame and if the beam-column connectionfail to handover the stress, the load transfer will be interrupted. Therefore, the ductilityof the whole structure depends on the ductility of the nodes. At present, the domesticand foreign scholars study on ductility node is mostly confined to the plastic hingerelocation mechanism of the node itself, but there is little researches on the overallseismic mechanism of the ductile steel frame using new node. Consequently, it’snecessary to make the overall stress analysis on the development regularity of plastichinges and the yield mechanism of the new ductility node steel framework.This paper is based on the researchand development status of new type of ductilitynodes and design the steel frame size according to our country related architecturaldesign standards and U.S. design norms. Then, set up the ANSYS finite element modelof the flange-weaken node steel frame, cover-plate reinforced node steel frame and theordinary node steel frame. Making the modal analysis and the dynamic elastic-plastictime history analysis respectively under the action of the EL Centro wave, wenchuanearthquake wave and Lanzhou wave. This paper analyzes the whole deformation andinternal force response, the elastic-plastic stress and strain development, the plastichinge mechanism, the floor damage distribution and the collapse resistance of thedifferent types node steel frame under the action of seismic wave.The modal analysis result shows that the difference of the top five orders ofvibration period of different node type steel frame is small which indicates that thewhole framework stiffness is less affected by node stiffness. The dynamic elastic-plastictime history analysis shows that the new ductility nodes all achieves the relocation ofplastic hinge under the actionof three kinds of seismic waves, the plastic hinge scope isbigger and get more fully plastic development. These eventually improve the energydissipation capacity of frame and make the ductility and bearing capacity of theframework better. In the overall analysis, the law of deformation and internal forceresponse of the different node types steel frame are basically the same Theflange-weaken node frame absorbs less seismic force and seismic response is relativelysmall, but the cover-plate reinforced node steel frame will produce a relatively large earthquake displacement and internal force response. Incremental dynamic analysisshows that both the flange-weaken node steel frame and the cover-plate reinforced nodesteel frame changed the order of the beam end plastic hinge appeared and the powertransmission path of steel frame through the relocation of plastic hinge. Theseeventually formed a "weak group floors " and the plastic development is more even inthe middle of steel frame. Compared with the focused plastic damage of the weak layerin the ordinary steel frame, both of the ductility node steel frame achieve a betterseismic performance with the even and small floor damage. The research results canprovide a theoretical reference for the engineering application of new ductility nodes.