| As a new type of light steel structure,the honeycomb portal frame is gradually increasing in the domestic and international light steel structure projects.However,there are relatively few studies on the seismic design theory and design method for this kind of structural system at home and abroad.The existing design theory can not fully reflect the whole process of the structure under earthquake action,which limits the application and popularization of the structure.Therefore,the mechanical performance of the honeycomb portal frame under the action of the earthquake has become an urgent problem to be solved.In this paper,portal frame with hexagonal hole and variable cross section honeycomb beam is taken as the object of study.Through the analysis of the static bearing capacity and deformation of the structure,the section size of the honeycomb beam and the solid column are determined.The seismic performance of the structure is studied by theoretical analysis and numerical simulation.The finite element model of the honeycomb steel frame structure has been established and compared with the experimental results.The rationality of the parameter setting in the model is verified,which lays the foundation for the seismic performance analysis of the honeycomb beam portal frame.Simulation analysis of the structural model under uniaxial static loading and low cyclic loading.The influence of the opening ratio and the distance between the first hole to the column edge on the yield load,yield displacement,the hysteresis curve,the skeleton curve,the ductility and the energy dissipation capacity of the structure and the structural mechanism of the plastic hinge and the final failure mode are obtained.The influence of the opening ratio and the distance from the first hole to the column edge on the natural frequency of the hexagonal-hole honeycomb beam portal frame with variable cross section was analyzed under the modal analysis;the elastic-plastic dynamic time-history analysis of honeycomb beam portal frame structure was carried out,the dynamic responses on the top of the column,on the roof of frame and base shear force of the structure under different ground motions are studied;the dynamic response of the structure under different seismic intensity and different seismic wave and the stress state on the opening hole are analyzed;and the dynamic response of the rigid frame frame structure under the same working condition is compared and analyzed.The horizontal shear force method is used to calculate the horizontal seismic force of structural is compared with that of time history analysis method,the time history analysis method can meet the requirements of seismic code.The results show that the failure modes of rigid frame under different parameters are basically the same.The failure mode is that 3 plastic hinges are formed on the honeycomb beam with variable cross section.Compared with the common portal frame structure,the plastic hinge is transferred from the beam column joint to the honeycomb hole.While the plastic hinge is formed,the ductility of the structure is improved,but the energy consumption is decreased.The ductility and energy dissipation capacity of the honeycomb beam portal frame is better than that of the solid web portal frame.The influence of the opening ratio on the seismic performance of the structure is obvious.The influence of the same parameters on the dynamic response of the structure under different seismic waves is different,it is shown that the spectrum characteristics of seismic waves have a great influence on the dynamic response of structures.Under the same condition,the maximum acceleration on top of column and on the roof frame also and base shear force of the solid web portal frame are larger than those of the honeycomb beam portal frame.The calculation results of time history analysis method can meet the requirements of seismic code under the condition of frequent earthquake. |
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