Research On Nonlinear Behavior Of Bolts-endplate Semi-rigid Connections For Concrete-filled Square Tubular Column And Steel Beam

Bolts-endplate connection, one of the connections that usually used in concrete-filled square tubular column and steel beam connections, is favored in domestic and international engineering. There are relatively more components and when loaded, it showed a clear non-linear behavior, the form of force and deformation is complex. Currently, there is no specification for the design of the connection, the research on the connection is also not extensive and in-depth.In this paper, the nonlinear behavior of Bolts-endplate semi-rigid connection was analyzed by three-dimension nonlinear finite element program. Compared with the results of the theoretic formula in literature 34, the two results were dovetailed nicely with each other. Through analyzing 11 series of total 28 Bolts-endplate connection samples by finite element and discussing the effects of those parameters to connection behaviors. It comes to the conclusion that Bolts-endplate connection is semi-rigid and its plastic deformability is good; the thickness of end plates, the stiffening plates of the end plates and the height of beam section have great influence on the connection mechanical behaviors; the diameter of high-strength bolt, the bolt spacing arrangement, the axis ratio and the tubular column section size have a certain influence on the connection mechanical behaviors; given that capacity requirements is satisfied, the thickness of steel beam and tubular column have less influence on the connection mechanical behaviors; the friction factor of the bolts and the concrete strength have hardly influence on the connection mechanical behaviors. At the same time, compare the bolts-endplate semi-rigid connection with the rigid connection on the connection mechanical behaviors, we get two kinds of circumstances of contrast conclusion; based on the result of finite element analysis, the theoretical calculation methods of bearing capacity to the bolts-endplate connection were established.According to the conclusion of this paper, which provide references and advices about the engineer design.