| As the transmission hub of the whole structure,the seismic performance of the beam-column joint plays an important role in the safety of the whole structure.Some problems inevitably exist in the process of assembly and application of the existing special-shaped concrete-filled steel tube column frame joints at home and abroad.At the same time,with the development of the recoverable functional structure,more and more scholars begin to pay attention to and study how to make the structure can be quickly restored to production and use after the earthquake.In order to promote the application of profiled column frame structure system(CFST-RSPJ).In this paper,based on the characteristics of mild steel damper,a new type of shear plate joint of special-shaped concrete-filled steel tube structure is proposed,and its seismic performance is systematically studied by means of test and numerical simulation.The main contents are as follows:1.This paper introduces the design principles and classification standards related to the frame joints of concrete-filled steel tubular columns,and deduces the initial stiffness of the shear plate joints of corner columns of profile-shaped concrete-filled steel tubular frames,which provides a theoretical basis for the subsequent design and low-cycle reciprocating load test of the joints.2.A new type of special-shaped concrete-filled steel tubular structure shear plate joints with waist-hole shear dissipated plates and rectangular hole shear dissipated plates were designed respectively.A low cyclic reciprocating load test was carried out to obtain the mechanical properties of the two joints,such as hysteretic curves,skeleton curves,ductility properties,energy dissipation capacity and stiffness degradation,and the data were compared and analyzed.The results show that the failure modes of the new special-shaped concrete-filled steel tube(CFST)shear plates with different openings will be different.The failure modes of the new special-shaped concrete-filled steel tube shear plates with waist-hole shear plates are ideal,with full hysteresis curves,high bearing capacity,stable stiffness degradation,good ductility and energy dissipation capacity.3.The finite element model of shear plate joint of new special-shaped concrete filled steel tube structure is established.The model considers the problems of material,geometric nonlinearity,contact between concrete and special-shaped steel tube column wall,and gives the solution of element selection,analysis step and interaction setting,load and boundary conditions.After comparing with the test results,It is found that compared with the experimental results,the error of the calculated model is controlled within 10%,which verifies the correctness of the established node model and lays a foundation for the parametric analysis in the next chapter.4.On the basis of test and numerical simulation,a total of 20 finite element models with different parameters were established by changing the axial compression ratio of joints,friction coefficient between plates,thickness of shear energy-dissipating plate,opening rate of shear energy-dissipating plate and steel strength of shear energy-dissipating plate.The stress nephogram,hysteresis curve and skeleton curve of the models were compared and analyzed.The influence laws of different parameters on the seismic performance of the joints are obtained,which provides design suggestions for the reasonable values of the components of the shear plate joints of the new special-shaped concrete-filled steel tube structures in practical engineering. |
