| Concrete-filled double steel tubular column has many advantages,such as: high collapse resistance and compressive bearing capacity.According to the cross-section form of the column,the concrete-filled double steel tubular column has a variety of classifications.Among them,the concrete-filled steel tubular column with the inner circle and the outer square is the most beautiful and clean,and has the characteristics of simple joint construction.Therefore,this paper will take the concrete-filled steel tubular column with the inner circle and the outer square as the research object.At the same time,H-shaped steel beam has great potential and development space,which is manifested in the light weight and high strength of H-shaped steel beam,and the easy opening of H-shaped steel beam according to actual needs.However,the current research status at home and abroad is that although some research has been done on the joint of concrete-filled double steel tubular column and H-shaped steel beam,there are still some problems such as complex structure and poor seismic performance of the joint,which largely hinders the development and application of the concrete-filled double steel tubular column and H-shaped steel beam system.In order to promote the extensive application of concrete-filled double steel tubular column system,this paper designs a new type of concrete-filled double steel tubular column and H-shaped steel beam joint: diaphragm-through joint.In this paper,the numerical simulation test of low-cycle reciprocating load is carried out.At the same time,the method of combining numerical simulation with theoretical analysis is also used to study the seismic performance of this new joint.The main research contents and conclusions are as follows:（1）ABAQUS was used to research the commonly used and existing joint of concrete-filled double steel tubular column and H-shaped steel beam: the vertical rib joint,modeling analysis.By comparing the simulated results with the experimental results of others,it is verified that the correctness of the model and the reliability of the results（2）A new type of concrete-filled double steel tubular column and H-shaped steel beam joint is proposed: diaphragm-through joint.The ultimate failure mode and a series of seismic performance indicators of the new type of concrete-filled double steel tubular column and H-shaped steel beam joint are studied in detail.The finite element models of the new concrete-filled double steel tubular column and H-shaped steel beam diaphragm-through joints are established.The results show that the fullness of the hysteretic curve of the new concrete-filled double steel tubular column and H-shaped steel beam diaphragm-through joint is excellent when the low-cycle reciprocating load is applied to the beam end of the H-beam on both sides of concrete-filled double steel tubular column.The other seismic performance indexes are good.Thus,the new concrete-filled double steel tubular column and H-shaped steel beam diaphragm-through joint will have good application and promotion value.（3）The finite element models of sixteen new concrete-filled double steel tubular column and H-shaped steel beam diaphragm-through joints are established.The influence of steel strength,beam-to-column linear stiffness ratio,concrete strength,axial compression ratio and other parameters on the seismic performance of the new concrete-filled double steel tubular column and H-shaped steel beam diaphragm-through joint is studied.There is no obvious difference in the seismic performance of the specimens under axial compression ratio,but the joints quit work earlier because of excessive axial compression ratio.The higher the steel strength of the steel beam,the more easily the stress concentration phenomenon appears in the core area of the joint.The steel strength of the steel beam has a great influence on the seismic performance of the new joint.When the beam-column rigidity ratio is too small,large high stress zone will not appear in the specimen,which will cause the waste of materials.When the beam-column rigidity ratio is too large,the hysteretic curve of the specimen is not full.The seismic performance of specimens with different concrete strength has no significant difference.The different steel pipe forms affect the stress of the joints. |
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