| Prefabricated frame structure has the advantages of flexible space layout,rich building facade,short construction period,high construction quality,energy saving and environmental protection,and has been widely used in various public buildings and industrial buildings.In the prefabricated frame structure,the traditional precast reinforced concrete(RC)beam has the disadvantages of complex joint structure and difficult construction.In order to promote the application of precast RC beam in the prefabricated frame,combined with the characteristics of convenient construction of steel structure,the section steel is embedded at both ends of the RC beam to form the RC beam with embedded section steel joint.The current research on this kind of component is mainly focused on the RC beam body itself or the joints assembled by the embedded steel joints.Obviously,such a simplified treatment cannot completely simulate the overall mechanical behavior of this kind of beam in the actual engineering prefabricated frame structure.In order to further study the overall mechanical properties of prefabricated frame structure of RC beams based on embedded steel joints,this paper conducts numerical simulation research on the mechanical properties of prefabricated concrete-filled steel tubular pillar-RC beam frame structure based on practical engineering.The main work contents and research results are as follows:(1)Establishment of finite element model.Based on practical engineering,the finite element model of prefabricated concrete-filled steel tubular column-reinforced concrete beam frame structure with single layer and two span embedded section steel is established by using large general finite element software ABAQUS.The model takes into account the effects of geometry,material and contact nonlinearity.According to the spatial position relationship of the primary and secondary beams in actual engineering,the three-point concentrated loads are applied to the frame beams.The mechanical properties of such prefabricated frame structures under static loads are studied,and the load-deflection curve,deformation,stress-strain and damage development of the structures are analyzed in detail.The failure modes of these structures under three-point static load are summarized.(2)Test scheme design and test data analysis.According to the actual project,the test component was made,and the test scheme was designed.The test results and test data were analyzed from the aspects of load-deflection curve,failure pattern,crack development law and material strain of key section.The reliability and accuracy of constitutive model,interaction,boundary conditions and mesh division of the established finite element model are verified by comparing the measured data with the simulation results of finite element model.(3)Parametric analysis of structural design.Based on the actual engineering prototype model,parameterized analysis in different directions such as geometry size,material strength and construction measures was carried out respectively,and the influence law of different parameter changes on the structural bearing capacity,shear ductility and initial stiffness was summarized.The applicable range of different parameters was determined,and the reference suggestions were put forward for the actual engineering structure.The research results can provide some reference for similar projects.(4)Formulation of bearing capacity calculation formula.According to the applicable scope of the bearing capacity design method in the current concrete structure design code(GB50010-2010)and composite structure design code(JGJ138-2016),the application limitation of the prefabricated frame structure in the current code calculation method is analyzed.On the basis of the previous research conclusions and the content of this paper,the calculation formula of the bearing capacity of each component of the prefabricated frame is summarized.The error between the calculation results and the numerical simulation results is very small,which can provide a basis for the design of similar structures. |
PDF Full Text Request