# Study on New Bolted T-Stub Connection with Inserted Plates under Axial and Cyclic Loads
## 6 Conclusions  
This study focused on the energy dissipation capacity of T-stub connections of semi-rigid steel beam-column joints. A new T-stub connection with two plates being inserted between T-stub flange and column flange is put forward. To fully understand its mechanical performance, the corresponding compressive mechanical model was figured out, then three groups of 30 specimens with distinctive configurations were analyzed through axial and cyclic loading experiments, and the following conclusions were drawn:  
1. The proposal regarding the insertion of two rectangular plates beneath the T-stub flange to promote the mechanical properties of the component is feasible.
2. The two failure modes of new T-stub connections under tension in the test are identical to those explored in previous studies, as expected. Meanwhile, the two compressive failure modes from tests conformed to the mechanical model this study set up. The first mechanism featured plastic hinges forming a flange-web connection with the flange above the inner sides of two plates, while the second involved plastic deformation occurring at the flange-web connection, as well as two bolts.
3. The existence of two plates did not substantially strengthen the tensile properties, but effectively elevated the compressive strength, stiffness and ductility of the specimens. Furthermore, the compressive forces obtained through the tests agreed well with the formulas presented in terms of compression bearing capacity.
4. The hysteresis loops of specimens designed according to the Type 1 failure mode were plump and stable, while those based on the Type 2 failure mode revealed a pinched effect, as did the specimens with a plate width exceeding 46 mm.
5. The T-stub connections fabricated by means of welding surpassed those from hot rolled steel sections in terms of rigidity and ductility performance, with the overall energy consumed by former capable of rising by about 14% compared with the latter.
6. An average of 50% improvement on energy dissipation capacity can be expected after the two plates are assembled. An increase of 16% energy dissipation capacity is possible for each 10 mm increment in flange length. The energy dissipation capacity also increased by 10% and 23% for every 2 or 6 mm growth in plate width, respectively, up to 46 mm in total.
7. The geometric relationship matching the optimal width of the plates herein refers to the plate width roughly taking up 31% of flange width; in this case, the ratio of distance between the inside of the plates and the bolt centerline to the distance between the bolt centerline and the flange-web connection was about 4:3.  
Conceptualization, Z.W.; methodology, X.Z.; Data curation, X.Z.; Conceived and designed the experiments, X.Z.; Performed the experiments, X.Z.; Analyzed the data, X.Z.; Contributed reagents/materials/analysis tools, Z.W.; Writing, X.Z. All authors have read and agreed to the published version of the manuscript.  
This research has been supported by National Natural Science Foundation of China, grant number 51008081.  
The authors would like to acknowledge Fujian Academy of Building Research, for laboratory and technical support.  
The authors declare no conflict of interest.