## 3 Materials and Methods
### Specim Description and Configurations
In the case of the 180 mm frame, the term \"four-clamp configuration\" used in subsequent sections refers to the total number of clamps in the connection, including both the L-shaped upper plate and the triangular frame itself. Specifically, four clamps were applied to the upper plate and three to the frame. This distinction is crucial to avoid misinterpretation and is consistent with the schematic presented in Figure 6a. This systematic variation in frame geometry and clamp distribution enabled a comprehensive analysis of their effects on load-bearing capacity and stress distribution. Figure 5 illustrates the clamp configurations tested for the 260 mm triangular frame: four clamps (Figure 5a), three clamps (Figure 5b), and two clamps (Figure 5c). Similarly, Figure 6 depicts the clamp arrangements for the 180 mm frame, maintaining the same testing logic and layout across both frame types. Clamp placement was strategically designed based on the expected load path and structural response. Under vertical loading, the connection undergoes a combination of tensile and compressive forces. As shown in Figure 7b, the rear upper clamps are primarily subjected to compression, while the front upper clamps experience traction. Conversely, the  
Figure 4: Side views of the beam-to-column assembly: (**a**) framework with the 260 mm triangular frame; (**b**) framework with the 180 mm triangular frame, including key dimensions. rear clamps on the lower side are under traction, and the front ones are under compression. This pattern reflects the anticipated rotational behavior of the assembly and supports structural efficiency. Figure 5: Schematic representation of the clamp configurations tested for the 260 mm triangular frame: (**a**) configuration with four symmetrically distributed clamps; (**b**) configuration with three clamps; (**c**) configuration with two clamps. The red arrow indicates the location where the vertical load was applied. Figure 6: Schematic representation of the clamp configurations tested for the 180 mm triangular frame: (**a**) configuration with four clamps on the top and three on the 180 mm triangular frame; (**b**) configuration with three clamps on both the top and the frame; (**c**) configuration with two clamps on both the top and the frame. Figure 7: Connection behavior under vertical load: (**a**) load application at the beam’s end; (**b**) rotational response showing traction and compression zones in the clamps. Maintaining symmetric and standardized clamp distributions across all configurations ensured assembly consistency and reliable comparisons. This methodological consistency allowed for a precise evaluation of how frame size and clamp quantity influence the connection's mechanical response, including stress distribution, load-bearing capacity, and overall structural integrity. The fasteners used in the tests consisted of high-strength bolts in compliance with M12x70-class 8.8-zinc-coated [34; 35], nuts HR-M12-class 8.8-zinc-coated [36], and washers M12-Class 300 HV-zinc-coated [37]. All fasteners were sourced from the same manufacturer to ensure uniform performance [37]. Application of Pre-Tension and Stepwise Loading  
A uniform pre-tension of 42.916 N was applied to all configurations to ensure proper bolt fastening, replicating real mounting conditions. The procedure followed the continuous torque method [32]. The torque application was carried out using a manual torque wrench with \(\pm\)4% precision [38] in two steps:  
1. First, an initial tightening was performed, applying 75% of the reference torque, resulting in 69.5 Nm;
2. Second, a final tightening was applied at 110% of the reference torque, corresponding to a final torque of 102.0 Nm. The adopted reference torque was 92.7 Nm. This procedure compensates for friction coefficient variations and ensures a final pre-load of approximately 43 kN.