| In recent years,with the country’s comprehensive promotion of the modernization of the construction industry,prefabricated buildings have become a development trend that guides the transformation and upgrading of the traditional construction industry to green buildings.As an important part of prefabricated buildings,steel tube concrete structures combine the advantages of steel and concrete and are widely used in major projects.However,the node area is still the weak part of the special-shaped steel tube concrete structure,and two improved joint forms are proposed for the special-shaped steel tube concrete structure and its seismic performance is studied.In this thesis,two joint improvement forms are proposed for special-shaped steel tube concrete structures,one is to propose a weakened joint form with oval holes in the beam flange;Second,a new type of multi-point dispersion energy-dissipation limit sector damper is proposed,and the seismic performance of the combined node of the application of two improved forms is studied and analyzed,and the main research content and conclusions are as follows:(1)Based on the finite element software ABAQUS,a three-dimensional finite element simulation model of the cross shaped steel tube concrete column I-steel beam frame node is established,and the finite element simulation results are compared and analyzed with the experimental results.Research has found that the failure characteristics,load displacement curves,and skeleton curves of the cross shaped steel tube concrete column I-steel beam node output through finite element analysis are consistent with the overall trend of the experimental components.The error between the bearing capacity and displacement simulated by finite element analysis and the experimental values is within 10%,and the various parameters set by the finite element model are reasonable.(2)A finite element model of a new type of prefabricated special-shaped column beam joint specimen with elliptical holes on the beam flange was established,and its seismic performance was studied and analyzed by changing factors such as flange aperture,web aperture,flange splice plate thickness,and axial compression ratio.Research has found that as the loading displacement at the beam end increases,the bolts in the flange expansion hole series node specimens begin to slip.The bearing capacity of the nodes in the sliding stage increases slowly,and the bearing capacity value is slightly lower than the original hole specimen.In the later stage of loading,the bearing capacity of the nodes has been increasing.The ultimate bearing capacity of the G-03 to G-06 node specimens has decreased by 1.2%,2%,3.7%,and 6.1% compared to the ultimate bearing capacity of the original hole specimen G-02,respectively,The maximum equivalent viscous damping coefficients increased by 2.3%,7.2%,10.7%,and 15.3%,respectively,and the displacement ductility coefficients increased by 5.4%,8.1%,8.4%,and 9%,respectively.(3)A finite element model of a new type of multi-point dispersed energy dissipation damper has been established,and its seismic performance has been studied and analyzed by changing factors such as shear steel plate thickness,number of constrained steel plates,limit displacement,and number of limit blocks.The results indicate that increasing the thickness of the shear steel plate significantly improves the bearing capacity and energy dissipation capacity of the new damper.The reduction in the number of constraint steel plates,limit blocks,and the increase in limit displacement result in a decrease in the overall seismic performance of the new damper.Compared to Z-01 specimen,the ultimate bearing capacity of Z-02 specimen increased by 34%,and the maximum equivalent viscous damping coefficient increased by 2%.However,the ultimate bearing capacity of Z-03,Z-04,and Z-05 specimens decreased by 42.3%,8.1%,and4%,respectively.The maximum equivalent viscous damping coefficient decreased by 12.9%,8.5%,and 4.2%,respectively.(4)Based on a new type of prefabricated steel tube shaped column beam node with a new type of multi-point dispersed energy dissipation damper,the synergistic effect of the two on the overall structure and seismic performance was studied.The results show that compared to the GZ-01 z and GZ-03 z specimens on the side without dampers,the ultimate bearing capacity of conventional nodes GZ-01 y and GZ-02 increases by 33.5% and 34.1%,the displacement ductility coefficient increases by 11.1% and 22.5%,and the maximum equivalent viscous damping coefficient increases by 10.1% and 5.3%;The ultimate bearing capacity of the expanded hole composite nodes GZ-03 y and GZ-04 increased by 17% and 13.7%,the displacement ductility coefficient increased by 25.2% and 32.6%,and the maximum equivalent viscous damping coefficient decreased by 11.4% and 13.5%. |
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