Study On The Mechanical Behaviors Of Semi-rigid T-stub Beam-to-column Connection Under Cyclic Load

In structural design, in order to simplify the calculation, Beam-to-column Connection are generally assumed to be fully rigid and ideally pinned. In fact, most of the beam-column connection are neither either fully rigid or ideally pinned, they belong to semi-rigid connection which lies between to the two extreme cases of fully rigid and ideally pinned.T-stub Beam-to-column Connection is a kind of node connection which connects beam with column by using high-strength bolts, it's the largest stiffness connection in the semi-rigid connection. This type of connection has many advantags, such as easy fabricated, low cost, large load-carrying capacity and good ductility which has found a preliminary application in engineering practice. However, the research of mechanical properties is not abundant in the country, so it's significant for theory and practice to study on the hysteretic behavior and failure mechanism of the T-stub Beam-to-column Connection node under cyclic load and put forward some countermeasures and suggestions for seismic design. It can supplies domestic research data, but also provides guidance for the practical project.In this paper, based on the previous studies at home and abroad, T-stub Beam-to-column connection specimens were tested under cyclic load. Effect of thickness of T-stub on hysteretic behavior of connections was considered under cyclic load. The test results indicate that specimens exhibit good ductile behavior. The thickness of T-stub significantly affects the strength and ductility of connection. And also the mechanical properties of full-scale model of the connection node under cyclic load were analyzed with nonlinear finite element method. After comparing the results of Finite element analysis with test results and FEM analysis were verificated, node stiffness, load capacity, the stress distribution of the key components and failure mechanism were emphasized, and hysteretic behaviors of the 43 specimens of 16 series were systematic analysied. The impact on the hysteretic behavior of connection by the change of major parameters including the dimension of T-stub, beam, column, the interval, diameter, grade and pretension of bolts, the strength of the material, friction coefficient, stiffeners and so on are studied, then the moment - rotation curves of node were drawn out, series of conclusions were summarized.The FEM results show that the dimension of T-stub, vertical interval of bolts on the T-stub greatly influence the hysteretic behavior of the connection, the influence of other factors are relatively small. At last, seismic strategy and design recommendations based on the results of tests and FEM analysis are suggested for applying the T-stub Beam-to-column Connection.