| At present,China's construction industry is in the stage of transformation and upgrading,and prefabricated building,as the carrier of the transformation and upgrading of the traditional construction industry in our country,is being vigorously promoted.Developing prefabricated buildings is a transformation of construction methods,a progress of social productivity,and an evolution of social forms.However,in our country,the development of assembly building has been hindered in a certain period because of the defects of integrity and poor seismic performance of traditional assembly building.Throughout the development of assembly buildings abroad,fabricated structures have been widely used in Europe,America,Japan and other developed countries,and have shown excellent integrity and seismic performance.Therefore,to make the assembly building have further application and development in our country,we should combine the research technology of existing assembly building,the existing national conditions and economic situation of our country,and carry on the technical innovation and improvement to the malpractice of the traditional assembly building.In view of this,this paper starts with the research of the assembled concrete frame structure system,and applies the bolt-end plate connection in the steel structure and the composite structure to the reinforced concrete structure.A kind of frame structure of core-piercing high strength bolt-end-plate connection is formed,and the pseudo-static test is carried out with eight high-strength bolt-end-plate connection concrete components.The main contents and research results of this paper are as follows:(1)The pseudo-static tests of eight core-piercing high-strength bolt-end plate confined concrete beam-column assemblies are completed.The crack distribution,development and failure modes of the specimens are qualitatively understood,and the hysteretic curve,skeleton curve,displacement ductility,strength degradation,stiffness degradation and energy dissipation capacity are quantitatively analyzed.The results show that plastic hinge failure occurred at the beam ends of all specimens,and no shear failure occurred in the core area of the joint,indicating that the connection form can achieve the design purpose of “strong joint”.From the final failure of the specimen,the non-prestressed reinforcement was pulled off,and the welding form of pier head adopted by the non-prestressed reinforcement and the end plate did not have the phenomenon of breaking and welding,which can meet the requirements of reinforcement force transmission.Judging from the seismic performance index,the assembly shows good deformation capacity and energy dissipation capacity.(2)The factors affecting the shear capacity of the core zone of the through-core high-strength bolt-end-plate connections are analyzed.The shear resistance of core concrete is considered according to the diagonal compression bar mechanism.According to Kupfer-Gerstle yield criterion,the strength of core concrete is improved by the pre-tightening force of bolts and the axial force of columns.According to the fourth strength theory,the shear resistance of steel hoop itself can be obtained.Finally,the calculation formula of the shear capacity of the core region of the node is proposed.Combined with the experimental data of related literatures,the calculated values of the theoretical formula are compared with the experimental values.The results show that the calculated values agree well with the theoretical values.(3)Based on the variable-angle truss-arch model and considering the manifestation of truss-arch model under various conditions,the shear capacity formula of oblique section of unbonded prestressed high-strength spiral stirrups confined concrete beams under various conditions is proposed.According to the mechanical characteristics of unbonded prestressed concrete beams and relevant basic assumptions,the flexural capacity of unbonded pre-stressed concrete beams is analyzed,and the formulas of flexural capacity under different reinforcement failure are put forward.Combining with the experimental data in the relevant literature,the calculated values of the theoretical formula are compared with the experimental values.The results show that the calculated results of the formula in this paper are consistent with the experimental values.(4)According to the mechanical characteristics of the welded pier head with non-prestressed tendons and end plates,the calculation formula of the outer diameter of the welded pier head is derived.According to the different failure modes of high-strength bolts,the corresponding shear bearing capacity formula of high-strength bolts is given.Based on the stress characteristics of the through-core high-strength bolt-end plate,the end plate is simplified as a simply supported beam model.According to the balance,the maximum bending moment of the end plate can be obtained,and then the thickness of the end plate can be determined.Through the research on the stress mechanism of the through-core high-strength bolt-end plate joint,the calculation formula of the horizontal shear force acting in the joint can be determined,and the cross-sectional area of the steel plate hoop can be determined when the shear failure in the core area of the joint is ensured.(5)Based on the research results of reinforced concrete,the skeleton curve models of unbonded prestressed concrete beams and high-strength spiral stirrup confined concrete columns are proposed,and the calculation methods of each key point are determined.The restoring force model of high strength bolt-end plate assembly with through core is given by fitting regression method of test data.In addition,the determination method of skeleton curve eigenvalue for pure shear layer model and bending shear model is given.(6)According to the damage characteristics of the through-core high-strength bolt-end plate frame structure itself,and considering the plastic hinge state of the end of the component,the performance level of the through-core high-strength bolt-end plate frame structure is established,and the quantitative index values of the through-core high-strength bolt-end plate frame structure at various performance levels are given.Finally,based on the modified Park-Ang two-parameter model,a seismic design method based on displacement and damage performance is proposed. |
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