Study On Seismic Performance Of Self-centering Rocking Steel Frame Based On Disc Springs

The steel frame structures which are constructed based on the traditional seismic design method possess good overall seismic performance in previous large earthquakes,which effectively guarantees the life safety of residents.But at the same time,many post-earthquake investigations indicate that traditional steel frames are seriously damaged after strong earthquakes and serious yielding or buckling can be observed in beam to column connections and column bases,meanwhile,the residual deformation is large.The costs of maintenance and repair are expensive or cannot be maintained,resulting in the disruption of the use function of buildings.Moreover,the economic losses and social impacts are significant.In view of the above problems,this paper developed a series of resilience connections and structural systems,including prefabricated self-centering resilient rocking steel column,prefabricated self-centering friction energy dissipation beam to column connection and prefabricated self-centering rocking steel frames.Following the research ideas from connections to structural systems,a series of research methods are adopted,including theoretical analyses,experimental researches and numerical simulations.The specific research contents are as follows:(1)In this paper,a new type of prefabricated self-centering resilient steel column is put forward,its construction form and working mechanism are introduced and its restoring force model is established through theoretical analyses,the influence of different design parameters on its mechanical properties is studied,and its simulation analyses are carried out by using the finite element software ABAQUS,the simulation results reveal that the working mechanism and self-centering mechanism of the column base,and it can obtain the corresponding initial stiffness,decompression moment,maximum moment and bending moment-drift hysteretic relationship,in addition,the seismic performance of self-centering resilient steel column is compared with that of traditional steel column.The energy calculation formulae of self-centering resilient steel column at the maximum design displacement are derived based on the principle of energy conservation,the correctness of the restoring force model and the energy calculation formulae are verified by the finite element analyses.(2)A new type of prefabricated self-centering beam column friction energy dissipation connection is proposed,the self-centering principle and energy dissipation mechanism of the connection are analyzed.In order to study its seismic performance comprehensively and deeply,in the early stage of the study,the low cycle reversed loading test was carried out on the rotation friction hinge without self-centering component,the influence of the initial pre-pressure of the rotation friction hinge on its seismic performance was studied,the restoring force model was proposed and the comparison between the test results and the calculation results which are based on this model was performed.A self-centering beam column friction energy dissipation connection with a scale of 1/4 is designed and manufactured.The mechanical deformation characteristics,hysteretic curve,skeleton curve,residual deformation,stiffness degradation and energy dissipation performance of the connection are analyzed through the low cycle reversed loading test.The restoring force model is proposed through theoretical analysis,and the seismic performance of the connection is comprehensively studied.(3)Two new types of prefabricated self-centering rocking steel frame are presented.The first one is prefabricated self-centering friction energy dissipation rocking steel frame.The structure form and working mechanism of the structure are described in detail,and the restoring force model of the structure is established through theoretical analysis.The traditional steel frame structure model of single layer and double layer prefabricated self-centering rocking steel frame structure model are designed.The hysteretic performance of the structure model is simulated by the finite element software ABAQUS and the seismic performance of the two kinds of steel frame structures is comprehensively compared and analyzed.The second is the prefabricated self-centering metal energy dissipation rocking steel frame.A self-centering rocking steel frame with a scale of 1 / 4 is designed and manufactured.The low cycle reversed loading test is carried out on the test specimen,and its seismic performance is comprehensively studied,including the characteristics of loading deformation,hysteretic curve,skeleton curve,residual deformation,energy dissipation performance,stiffness degradation,strength degradation and earthquake resilience.The influence of different disc spring preloading and vertical axial force on its mechanical properties is analyzed.The calculation method and value range of its key mechanical properties are put forward.The refined numerical simulation model is established by the finite element analysis software,and the deformation energy dissipation mechanism of the self-centering rocking steel frame is studied and verified.The engineering practical design method of the steel frame structure is proposed.(4)A kind of self-centering metal energy dissipation damper which can be installed in steel frame is proposed.Its construction form and working mechanism are described.The restoring force model and design method of self-centering damper are put forward.The numerical analysis model of self-centering metal damper is established based on the finite element software ABAQUS,and the low cycle reversed loading simulation is carried out.The influence of spring initial pre-pressure,yield strength of metal damper and initial clearance of structural member on the seismic performance of self-centering metal damper is studied.The hysteretic performance of self-centering metal damper under different working conditions are compared and analyzed comprehensively,and the design improvement suggestions are given.The correctness and rationality of the restoring force model are verified by comparing the results of the finite element simulation and the calculation results of the restoring force model.