Research On The Mechanical Properties Of Steel Beam-To-Column T-Stub Semi-Rigid Connection With Test And Simulation

Steel frame is a common structural system in construction engineering. Because of its light weight, high strength, good seismic performance, short construction period, recycling use, little environmental pollution, good sustainability and other comprehensive advantages, once was known as the "green building" in twenty-first Century. Beam-to-column connection has been a hot topic in the research of steel frame. A large number of traditional welding node destroy brittle in Kobe, Japan and the United States Northridge earthquake. Typical semi-rigid connection with bolts has been paid extensive attention. Beam-to-column T-stub connection is a typical semi-rigid connection and it has a good ductility and seismic performance. In addition, it has a good applicability and broad application prospects for engineering structure. In order to improve the strength and stiffness of the node and to meet the design concept of "strong node weak component", this paper studies the enhancement of the node based on the existing tests of typical T-stub connections nodes. In this paper, means of experiment and numerical simulation are employed to study mechanical properties of T-stub connection nodes and the study is significant for the application and extension of structure of semi-rigid connections.The paper gives six kinds of structural strengthening scheme based on the mechanical properties of typical beam-to-column T-stub connection node, according to which eight full-scale model specimens have been designed ender low cycle loading in MTS electro hydraulic servo loading system. Then apply the ABAQUS finite element software to carry on the numerical simulation of the node test and to analyze the key parameters of the failure mode and the hysteretic behavior of the nodes, such as the indicators of strength, stiffness, ductility and energy dissipation. What is more, the influenced factors on the mechanical properties of the nodes are researched, such as increasing T-stub rib, increasing thickness, gradient broadening flange, beam webs with ribs and increasing the number of bolts. Further, the finite element simulation analysis is expanded to the node, analyzing the bolt pretension and friction between T-stub connection piece and flange contact surface can’t be detected in the test, in order to make up for the limitations of testing study. Finally, the main conclusions can be drawn as follows:(1) The failure mode of the connection node of T-stub is decided by the structure.(2) Among the six intensified methods, the factor affecting the bearing capacity and stiffness from high to low can be arrayed as the T-stub ribbing plate, T-stub thickening and ribbing, the number of bolts on the column and beam web with angle steel.(3) Increasing angle steel on the web of beam can improve the elastic limitation and ultimate deformation.(4) Among the strengthened ways of T-stub connection, according to the specific conditions of the project, choosing to T-stub’s rib, thickness, width and number of bolts can significantly improve the node strength and stiffness.(5) T-stub connection node has plumper hysteretic curve, better seismic performance and higher bearing capacity and ductility under cyclic loads.(6) The vertical cyclic loading at the end of the beam is mainly born by the friction in the contact surface of the T-stub and column flange.(7) The friction in the contact surface of the T-stub and column flange increases with the increase of load level. The maximum friction value is not associated with the strengthen way of T-stub.