# Study on New Bolted T-Stub Connection with Inserted Plates under Axial and Cyclic Loads
## 3 Test Specimen, Test Setup and Instrumentation  
A total of 30 T-stub connection specimens with distinctive configurations were tested under different types of loading conditions, including uniaxial tension, uniaxial compression and cyclic loads. In each specimen, the T-stub flange was bolted to a rigid base serving as the column flange in the beam-to-column joint by two high-strength bolts at the two sides with two rectangular steel plates  
Figure 2: Failure mechanisms of T-stub connections with inserted plates under compression, which can be categorized as: (**a**) Type 1 failure mode; (**b**) Type 2 failure mode. being assembled between them. Figure 3 depicts an elevation view and cross-section of the T-stub connection with inserted plates. In the graph, \(L\) and \(W\) are the width and length of the specimen, respectively; the former was constant at 150 mm in the test, while the latter varied depending on the strength of the T-stub designed. \(L_{p}\) is the width of inserted plates, which is a significant value by design. \(t\) and \(t_{0}\) represent the thickness of T-stub flange and web, respectively, both of which were determined by the strength of the T-stub designed like \(W.\)\(e_{2}\) is the distance from the bolt centerline to the front or rear ends of the specimen, which is always half of \(W.\)\(t_{1}\) is the effective width of the flange-to-web connection or the thickness of weld, depending on the fabrication method, which was taken as 0.8 times the inner arc radius of a rolled steel section and \(\sqrt{2}\) times the thickness of a fillet weld of welding steel by referring to the specifications in [28; 29]. \(m\) is the distance from the bolt centerline to the edge of the flange-to-web connection or the edge of the weld. \(e_{1}\), \(m_{1}\) and \(n_{1}\) represent the same as mentioned in Section 2; more specifically, \(e_{1}\) is determined by specifications, while \(m_{1}\) and \(n_{1}\) can be obtained based on other values. The primary parameters in this study can be summarized as follows:  
1. Setting or not setting the inserted plates, to measure the influence of plates on the mechanical properties of the connection (and the dissipation capacity in particular). 2. Relative strength of T-stub flange and two high-strength bolts, to verify the reliability of the proposed mechanical model for failure modes and load bearing capacity calculation. 3. Fabricating the connection by cutting from a standard steel section or welding two steel plates, to compare the impacts of setup on the mechanical properties of the connection. 4. Length of the T-stub flange and width of the inserted plates, to investigate the energy dissipation capacity of the connection then determine the optimum width of plates. On account of the research aims, this test is divided into three groups. Table 1 shows the target controlling parameters of specimens in different group with reference to symbols in Figure 3, as well as the force type (FT) of each specimen during test. The specimens in the first group T-stub Connection (TC) were manufactured from cutting part of the rolled profiles HN300\(\times\)150\(\times\)6.5\(\times\)9 of steel grade _Q235_[29]. The specimens in group Welding Connection A WA were composed by welding two plates of steel grade Q235 with thicknesses equal to 9 and 6.5 mm, while in group Welding Connection B WB two plates of steel grade Q235 with a thickness of 13 mm were employed. All the inserted plates were fabricated from steel grade _Q345_[29] with a constant thicknesses value of 20 mm. In series TC and WA, the bolt of property class 10.9s (with a diameter of 16 mm) was selected to form the relative strength relationship with weaker flange and stronger bolts. While the bolt of property class 8.8s (with  
Figure 3: Elevation view and cross-section of the T-stub connection with inserted plates. a diameter of 16 mm) was applied in series WB to shape the opposite relationship of stronger flange and weaker bolts [30]. The tags in Table 1 also allow identification of all the examined specimens.