| The composite structure of concrete slab and cellular beam can combine the advantages of cellular beam and composite beam at the same time,which is a kind of structural form widely used in engineering practice.At present,cellular beam and its composite beams have been made a comprehensive experimental research and theoretical analysis at home and abroad.However,these researches mainly focus on the static load,and the mechanical properties of cellular beam and its composite beams under dynamic loading are less,Which limits the application of cellular beam components.The cellular beam is weakened due to the opening of the web,and the cellular beam has a new failure mode compared with the ordinary steel beam.The local buckling of the web is one of the common forms.Buckling will lead to the rapid growth of the deformation of the member,and the failure of the component before reaching its plastic ultimate bearing capacity.Under the condition of low cyclic loading,the stress of cellular beams is more complicated.In order to study the hysteretic behavior and local stability of cellular beam and its composite beam under dynamic load,and hysteretic properties after local buckling of cellular beam and its composite beams,through combining the method of experimental research,theoretical analysis and finite element simulation to study the hysteretic behavior of cellular beam and its composite beam.The main contents include:Based on the quasi-static test of 3 specimens with different web thickness ratio,we observe and compare the damage form and the hysteretic behavior of the cellular beams.The results show that the failure mode of the cellular beam with larger web thickness ratio is local buckling of the web between holes,buckling will lead to deformation of the specimen increases sharply,resulting in the decrease of bearing capacity and the destruction of the specimen,the hysteretic behavior will deteriorate rapidly.As the web thickness ratio increases,this phenomenon is more obvious.On the basis of the experiment,the ABAQUS model is established to verify the rationality and correctness of the finite element model.Then through the finite element software to study the influence of different depth-web thickness ratio and different opening rate on the local stability,failure mode and hysteretic behavior of cellular beam,including including ductility,energy absorption and stiffness degradation,stiffness degradation,strength degradation and plastic deformation changes;Analysis considering the effect of the slab with different web thickness ratio and different opening rate on the local stability,failure mode and hysteretic behavior of cellular composite beam.The results show that the cellular beam with larger web depth-thickness ratio or less opening rate is susceptible to local buckling failure.In order to ensure the cellular beam have good hysteretic behavior,by comparing the seismic performance index of different cellular beams,the cellular beams web depth-thickness ratio should be controlled below 70,the opening rate should be around 60%.The bearing capacity and stiffness of the cellular composite beam considering the effect of the floor are obviously improved compared with the cellular beams with the same parameters,ductility and energy dissipation capacity are also improved in varying degrees.Under low cyclic loading concrete floor slab can not effectively prevent the local buckling of cellular beam,and the cellular beam web depth-thickness ratio and hole rate limit is also applicable to cellular composite beam.In this paper,some suggestions on the design of cellular beams and cellular composite beams are presented,which lays a good foundation for the popularization and application of this kind of structure. |
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