Experimental and numerical investigation of semi-rigid behavior top and seat T-Section connections with different triangular designed stiffener thicknesses

The top and seat T-section connections created using the IPE standard profile and T-shaped elements differ from those in the literature, which utilize welded plates. Thus, the elimination of the problems occurring at the welds of connections, such as fracture points and the inability to perform well in place, is expected. Knowledge of their behavior is needed to recommend the use of weld-less T-section connections. However, T-section connections that use the IPE standard profile are not mentioned or investigated in Eurocode 3. Furthermore, the T-section connections from standard IPE profiles aimed to use residue IPE standard profiles efficiently and back to the consumption cycle. This paper reports the results of 24 new laboratory tests on the moment-rotation curve characteristics of top and seat T-section connections with different triangular-designed stiffener thicknesses under static loading. Additionally, to understand the effects of the web length (T-section connection) and different triangular-designed stiffener thicknesses on the moment-rotation curve characteristics, the web length was chosen according to Eurocode 3 width of the T-section was taken to equal the width of the beam (IPE 160). Furthermore, the T-section ratios of flange thickness (tf) to web thickness (tw) were selected between 1.46 and 1.52 to understand how the effect of this ratio on the characteristics of the moment-rotation curves. The ex-periments also established and validated the finite-element models (ANSYS-work bench). The test results show that the maximum moment and energy dissipation value increased with increasing tf/tw (flange thicknesses to web thicknesses) ratios from 1.46 to 1.52. Moreover, the stiffness ratio values increased with increasing tf/tw ratios from 1.46 to 1.52, while they decreased with increasing tf/tw ratios from 1.46 to 1.48. Moreover, the number of bolt rows increased from 1 to 2, and the Frye-Morris values became much smaller than the experi-mental values. Additionally, in the model comparison with the 1 row of bolts T-connection, the stiffener used does not affect the moment capacity of the Frye Morris models. The mean value of the Mexp/MF-M ratio is be-tween 1 and 1.8 for the models with 2 rows of bolts. Therefore, the length of the T-connection used the stiffener effect on the moment capacity of the Frye Morris model with the two rows of bolts.