| Concrete filled steel tubular(CFST)is a new composite material with high bearing capacity,convenient construction and good fire resistance.Hollow compound CFST can reduce the weight of the structure effectively,which has been widely used domestic and overseas.At present,most of the structures using CFST are welded in site and then poured concrete,which has a great impact on the environment.Assembled structure is a new type of structure which is manufactured in factories and then assembled after being transported to the site.Assembled structure has the advantages of high construction speed,less pollution,energy and material saving,and has broad prospects for development.In this paper,according to the characteristics of composite concrete filled steel tubular(CFST)and assembled structure,a new type of butt-assembled CFST column-steel beam frame is designed.Low-cycle cyclic loading tests are used and numerical analysis is carried out by ABAQUS software.The aim is to obtain a new type of structure with good seismic performance and the characteristics of green energy-saving and environmental protection.The main contents and research results of this paper are as follows:(1)A new type of butt-assembling composite concrete filled steel tubular column-steel beam frame specimen and a traditional non-assembling composite concrete filled steel tubular column-steel beam frame specimen were designed.The new type of frame was designed with assembly joints in the middle of the column,and the two specimens were joined by pure bolts at the assembly position.Low-cycle repeated load tests were carried out on the two specimens respectively to analyze the failure phenomenon and deformation characteristics.(2)Based on the test results,the seismic performance of the two frames is studied comparatively.The hysteretic curve,skeleton curve,deformation performance,energy dissipation capacity,strength degradation,stiffness degradation and second-order effect of new and traditional frames are analyzed,and a practical restoring force model is proposed.The results show that the seismic performance of the new frame is good and slightly better than that of the traditional frame,which shows the rationality of the new frame design and the effectiveness of joint connection.(3)ABAQUS software is used to analyze the new type of docking assembled compositeconcrete filled steel tubular column-steel beam frame.On the basis of validating the rationality of the model,the force transfer characteristics and stress distribution among the components of the new frame are analyzed,and the effects of axial compression ratio,thickness of outer steel tube,steel strength,concrete strength of upper and lower columns and strength of grouting material in joints on bearing capacity and stress distribution are further studied.In this paper,the seismic performance of a new type of docking assembled composite concrete filled steel tubular column-steel beam frame is studied,which effectively combines the characteristics of concrete filled steel tubular and assembled structure,and provides a basis for the research and engineering application of the assembled composite concrete filled steel tubular structure. |
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