The Analysis On Mechanical Behavior Of Beam-To-Column T-Stub Steel Structure Connections With Inserted Plates

Beam-to-column connections is the key parts of the steel frame structures, the design idea of traditional T-stub connections is to form plastic hinges in the steel beam, so as to consumpe the conncetion’s energy, but once destroyed, it is difficult to repair and very costly. To solve this problem, the researchers proposed a new style connections:beam-to-column T-stub connections with inserted plates, the main features of this system are that set the bottom T-stub with the inserted plates as an energy dissipater, two plates are inserted into between the bottom T-stub and the column flange to increase the energy dissipation of T-stub. So that the top of beam flange is supposed as the rotational center, consequently, deform so small as to not damage, the T-stub dissipater locat at the bottom of beam flange and it is easy to be replaced.This paper studies mechanical behavior of beam-to-column T-stub steel structure connections with inserted plates under monotonic and cyclic reversed loading. The main work and results achieved are summarized as follows:Firstly, the numerical models of similar T-stub connections and beam-to-column T-stub connections with inserted plates were established by finite element software ABAQUS. Compared with the experimental results, the two results are dovetailed nicely with each other. It proves the finite model is valid and applicable. On this basis, the failure mode of the connection, the stress distribution and the law of development of the key parts were explored in the paper. The results show that when the lower T-stub is in tension, the plastic hinge occurs at the roots of the lower T-stub and the centeline of bolts. When the lower T-stub is in compression, the plastic hinge occurs at the roots of the lower T-stub and the edge of the inserted plates. The maximum stress and deformation appear at the roots of the lower T-stub when the connection is destroyed, and can ensure that the top of beam flanges as to be the rotation center, consequently, deform so small as to not damage.Secondly, through analyzing the behavior of 40 specimens of 16 series under monotonic and cyclic reversed loading, the changes of various geometric and physical parameters are studied to analyze the impact on the mechanical of the connections. The results indicate that the dimension of bottom T-stub flange, vertical interval of bolts on the bottom T-stub flange and the dimension of beam greatly influence the mechanical behavior of the connections; the dimension of the plate some little effect on negative mechanical properties. The other factors such as parameters including the dimension of the top T-stub flange, beam, column, the diameter, friction coefficient and so on have little impact on the mechanical of the connections.Finally, in consideration of the deformation of T-stub (including the bending of T-stub’s flange, the tension of bolt, the stretch of T-stub’s web), the deformation of column web and flange, based on the component method, the paper proposed a theoretical calculation moadel to compute initial rotational stiffness of the connections, and it is proved to be reliable by numerical example. And then several design recommendations for T-stub connections with inserted plates were proposed.