| With the development of Civil Engineering,some problems have been exposed in the traditional concrete-filled steel tubular structures,for example,the connection between concrete filled steel tubular column and steel beam with circular section is complicated,square(moment)section concrete filled steel tubular column with corner protruding wall.on the one hand,it reduces the use area of buildings,on the other hand,it affects the structure layout.To solve such problems,relevant scholars have proposed concrete filled steel tubular structures with special section.Beam-column joint is an important part of frame structure.In this paper,the connection structure of beam-column joints in Technical Specification for Rectangular Concrete Filled Steel Tubular Structures(CECS159:2004)is used for reference,in this paper,a new connection method of special-shaped concrete filled steel tubular column-steel beam joints with restrained tie rods is proposed.This kind of joint not only solves the outstanding shortcomings of prism,but also overcomes the disadvantages of complex construction of traditional beam-column joints,it provides a good scientific theory for the future application of special-shaped concrete filled steel tubular structures in practical engineering.Specific research contents are as follows:(1)Using ABAQUS,a large commercial software,a model of top-floor and side-joints of T-shaped concrete filled steel tubular column-I-shaped steel beam frame is established,finite element analysis,The failure modes,hysteresis curves and energy dissipation capacity obtained from the analysis are compared with the experimental results,determine the rationality of parameter selection for model building.On this basis,establishment of T-shaped concrete filled steel tubular short columns with restrained tie rods,the mechanical properties of short columns without restrained tie rods were compared and analyzed.The results show that:Concrete filled steel tubular columns with restrained tie bars can improve the ultimate bearing capacity of members to a large extent.(2)The ABAQUS finite element software is used to establish seven T-shaped concrete filled steel tubular column-steel beam joint models with restrained tie rods,By applying low cycle reciprocating load to the model,To study the axial compression ratio?external Short Beam Length?whether the special-shaped concrete-filled steel tubular column has restrained tie rods or not?whether to Set Four Parameters of Side Plate in Core Area of Node,the influence of seismic performance.With the increase of axial compression ratio,it has little influence on the ultimate bearing capacity,reduced energy consumption,It has no obvious effect on the degradation of strength and stiffness;With the increase of the length of the external short beam,its ultimate bearing capacity and energy dissipation performance show a trend of first increasing and then decreasing;The model of restrained tie rod is set up in the core area.The restrained tie rod can restrict the bulging phenomenon of steel tube and concrete in the core area to a large extent;he Ultimate Bearing Capacity of Side Plate Increased?the energy dissipation capacity has an obvious enhancement effect,It has little effect on strength degradation and can improve the initial stiffness.(3)On the basis of studying the connection mode of T-section concrete filled steel tubular column and steel beam with restrained tie rod in side plate connection,Thirdly,the connection modes of concrete filled steel tubular column and steel beam with side plate connection and restrained tie rod L-shaped and cross-section are put forward.The results show that:The hysteretic curves of two types of concrete filled steel tubular column-steel beam connections are full and their energy dissipation capacity is good,the failure of the model is mainly due to the plastic hinge at the end of the beam,It meets the seismic requirements of "strong node weak" members. |
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