## 3 Materials and Methods  
### Specim Description and Configurations  
This study investigates the behavior of a 90\({}^{\circ}\) beam-to-column connection using a clamp-based fastening system (Figure 3a). The connection at the top of the column is made using a 20 mm-thick L-shaped fixing plate (Figure 3b), while triangular frames are used at the bottom of the beam, where it interfaces with the column. These frames are critical for enhancing the assembly's stability and load capacity. Figure 3 provides a complete schematic of the beam-to-column connection, identifying the system's primary components: the beam, column, L-shaped fixing plate, two symmetrical triangular frames, and clamps (Figure 3a). Figure 3b details the dimensions of the L-shaped plate, while Figure 3c,d presents the two triangular frame sizes, 260 mm and 180 mm, respectively. Figure 3e represents the dimensions of the clamp. This visualization supports understanding the structural arrangement and the interaction among the connection components. The fixing plates and triangular frames were assembled using standard workshop welding for S275 steel, ensuring sufficient rigidity for elastic service behavior. Two main parameters were varied in the study: the size of the triangular frame and the number of clamps used in each configuration. The larger frame, measuring 260 mm (Figure 3c), contains five holes per side, allowing up to five clamps, whereas the smaller 180 mm frame (Figure 3d) accommodates three clamps per side, with two rows of three holes. In both frames, the outermost holes are positioned 30 mm from the edges to facilitate installation and ensure consistent bolt tightening. The selected frame sizes reflect practical applicability in industrial maintenance, support and temporary structures, modular shelving systems, and reconfigurable industrial assemblies [33]. This choice ensured that the tested geometries represented real-world conditions while preserving experimental feasibility. The clamp arrangements were defined to capture varying levels of structural restraint, balancing mechanical efficiency with reusability and modular adaptation. Figure 3: Geometry and configuration of the beam-to-column connection: (**a**) an isometric view of the assembly shows the frames and clamp system; (**b**) detail of the L-shaped upper frame with its main dimensions (20 mm thickness); (**c**) detail of the triangular lower structure measuring 260 mm (20 mm thick); (**d**) detail the triangular lower structure measuring 180 mm (20 mm thick); (**e**) detail of clamp with its main dimensions. Figure 4 complements this view with side elevations of the assembled system. Figure 4a illustrates the beam-to-column connection using the 260 mm frame, while Figure 4b shows the configuration with the 180 mm frame. The column has a total height of 1600 mm, and the beam spans 1000 mm horizontally. Both components are based on the IPE200 steel profile, with a flange width of 200 mm and a web thickness of 8.5 mm. The IPE200 S275 profile was selected due to its standardized geometry and mechanical properties, ensuring consistent stiffness and load transfer in both beam and column. This uniformity allows the structural response to be governed primarily by the connection behavior rather than by variability in member sections, enhancing the accuracy of experimental and numerical comparisons. Furthermore, using the same profile for both elements facilitates component reusability and interchangeability, which is essential for modular structural systems and aligns with design-for-deconstruction principles. The number of clamps was systematically varied for each frame size to assess the structural performance of the connections. For the 260 mm frame, configurations with four, three, and two clamps were tested (Figure 5). Due to geometric constraints, only three and two clamp configurations were feasible for the 180 mm frame (Figure 6). The clamps were symmetrically distributed in all setups to ensure balanced load transfer and consistent structural behavior.