# A Review of the T-Stub Components for the Analysis of Bolted Moment Joints
## 7 Discussion  
Readers will now understand that the T-stub component has been widely studied since [PERSON] and [PERSON] started their investigation of the T-stubs in tension. Nowadays, the study of the T-stub behaviour covers components under tension, compression, cyclic and impact loads of different types of connections. The different types of connections refer to the uses of backing plates, the type of bolt (standard, blind bolt, one side bolt) and the material of the T-stub. Additionally, many studies of the behaviour of the T-stubs at elevated temperature were developed. The present review article divided into three manners the way T-stubs were studied in order to determine if there are new ways of approaching the problem and found (as was hoped) that the first researchers approached the problem by performing experimental tests due to the limitations of the computational technology of the time. Therefore, analytical models were proposed to study the problem. For instance, [PERSON] and [PERSON] proposed some semi-empirical formulae, [PERSON] proposed an analytical model of the T-stub, [PERSON] proposed formulae that employed similar failure modes to the actual failure modes, etc. The analytical models are still being in used due to the fact their predictions can be obtained without the necessity of high computational hardware. Moreover, the codes such as Eurocode 8 and 9, AISC, etc. propose different formulae (according to the employed theory) for predict the T-stub behaviour. However, as aforementioned, the standards cannot cover all the possibilities of configuration of geometries or materials (as the last part of the review covers). Therefore, some proposed models based on EC3 (the beam theory) were presented in this review. These non-standardised models were validated against experimental data (the most reliable) and by developing FEM models. The FEM models provided the investigators with the possibility of comparing their models against numerical results of non-tested geometric configurations, which is the advantage of the numerical FEM models tools. This comparison could result in the modification of the proposed model due to the lack of accuracy for some scenarios, see [PERSON] [36,37] and [41]. This lack of accuracy could be caused by different factors, such as internal forces (bending or shear), geometry simplification, etc. that were not considered. Additionally, the comparison of the models of [PERSON] [24] and [PERSON] [25] against the EC3, experimental data and simulations showed that these proposed models should be improved with reliable (experimental and/or simulation) data to be more accurate. The last manner of studying the T-stub behaviour, informational models, is the least used and (considered by the authors newest) it is not common for traditional engineers who are more accustomed to analytical formulae found in the codes or employing FEM models. The informational model that was found in the literature was the one developed by [PERSON] et al. [78], and this is a hybrid approach between the FE method and metamodels based on soft computing (SC), which predicts the T-stub behaviour thanks to employing the data of FEM model and parametric study and experimental tests to teach and calibrate the informational model. As was mentioned, the informational models can developed their objective due to the neuronal networks that they employed, which is more common for computer science researchers, mathematicians, etc. Finally, according to the information that the authors could find in their literature review, they suggest that future investigation of T-stub connected by another kind of bolts such as the Ajax Oneside ST (standard tension and shear resistance) and Oneside Hi shear (standard tension resistance and high shear resistance). This type of bolts has one hardened split/collapsible washer, which could cause that the behaviour of the connection change due to the non-use of a solid washer.