# A Review of the T-Stub Components for the Analysis of Bolted Moment Joints
## 3 Experimental Testing
The main characteristic of the new connection is the use of friction T-stubs as energy dissipation devices and the post-tensioning high strength strands, which offered the self-centering capability. The study of this new connection was carried out by the experimental testing of five specimens that were tested under cyclic loads to understand the seismic behaviour of the connection. After the tests were performed, it was observed that the friction T-stubs provided stable energy dissipation ability, and the strands offer self-centering and eliminate the residual drift following a strong earthquake. Furthermore, the investigation proposed an analytical model to determine the yield and ultimate loads. In 2020 as well, [PERSON] and [PERSON] [51] published a study about T-stub connections with inserted plates, which allow the T-stub flange to yield under tensile or compression loads (see Figure 23). i.e., these plates enhance the dissipation of energy. The experimental part of this research work tested thirty T-stub connection at the Structures Laboratory at the Fujian Academy of Building Research, which was divided into the following three types of test: nine specimens were tested under monotonic tensile load, ten specimens under compression load and eleven specimens under cyclic load. The experiments showed that two inserted plates did not have a prominent effect on the tensile properties of the T-stub connection. The compressive properties grew with the increase of the inserted plates width. The T-stub under cyclic loads improved its energy dissipation capacity by 50% after the inserted plates are assembled. In 2020, [PERSON] et al. [52] carried out 25 tests on T-stubs (different flange thickness and bolt diameter) connected by thread-fixed one-side bolts to investigate the tensile behaviour under ambient and high temperatures (500 \({}^{\circ}\)C and 700 \({}^{\circ}\)C) and steady-state and transient-state (material properties were obtained at steady-state) conditions. In steady-state, the T-stubs were heated first, and when the temperature reached the desired value a load  
Figure 23: (**a**) Unstiffened T-stub bolted connection; (**b**) stiffened T-stub bolted connection; (**c**) different orientation of the single T-stub [51]. was applied until the force declined to 80% of the ultimate force. On the other hand, in transient-state, the preselected load (a ratio of 0.5 or 0.7 of the ultimate load) was applied first and kept for 2 min. Then, the T-stubs were heated. The tests were stopped when the T-stub carrying capacity dropped to 95% of the applied load, and this state was defined as the failure limit state. The tests showed that different four failures modes were observed at ambient temperature and elevated temperature. After the experimental tests, in steady-state, an initial stiffness decrement and a ductility increment were identified, with the elevation of the temperature. In transient-state tests, the temperature failure decreased with the increment of the load ratio (from 0.5 to 0.7). Besides, the heating procedure degraded the material of the shape and the bolt differently. Thus, different failure modes were observed at different temperatures (ambient and elevated temperature), e.g., four of the five potential failure modes were recognised. The suitability of use TOB T-stub was analysed by comparing the behaviour of the same T-stub but connected with standard bolts, and the results demonstrated that the ductility and tension strength were nearly similar. Finally, the modified design equations predict the behaviour of the TOB T-stubs at ambient and elevated temperature. In 2020, [PERSON] et al. [53] studied the behaviour of T-stubs with backing plates at ambient and elevated temperature.