## 3 Experimental Campaigns
### Experimental Results  
Table 3 shows the experimental results of the maximum load and shear stress (Fmax and \(\tau\)max, respectively), the elastic stiffness (Ke), and the shear modulus (Ge) obtained from the linear stage in the load-displacement diagrams. Also, the following table presents the displacement (\(8\)max) and angular distortion (\(8\)max/te) at the maximum load, where te is the distance (\(60\) mm) between the fabric embedded in the FRCM skins. To calculate the shear stress and shear modulus, the shear value from the dethatched FRCM skin (\(50\times 250\) mm) was used. The results in Table 3 show coefficients of variation ranging between \(2\) and \(14\%\) for maximum load and shear strength, respectively, indicating the good repeatability of the experiments, following [PERSON] and [PERSON] (2018). It is noteworthy that specimens without connectors presented a similar shear strength. However, for stiffness and displacements, the variation was higher, ranging between \(7\) and \(47\%\). This variability represents the expected scattering of data for elements composed of cementitious materials with a high non-linear behavior. The results presented in Table 3 are better appreciated in Figures 8-11. \begin{table}
\begin{tabular}{c c c c c c c c c} \hline
**Specimen** & **F\({}_{\text{max}}\) (N)** & \(\tau_{\text{max}}\) (MPa)** & **C.V** & **K\({}_{\text{e}}\) (N/mm)** & **G\({}_{\text{e}}\) (MPa)** & **C.V** & **\(\delta_{\text{max}}\) (mm)** & **\(\delta_{\text{max}}\)/te (\%)** & **C.V** \\ \hline SH-N & 1409.20 & 0.11 & (12\%) & 467.94 & 1.87 & (10\%) & 4.85 & 9.70 & (23\%) \\ \hline SH-H & 1694.60 & 0.14 & (6\%) & 601.05 & 2.40 & (19\%) & 5.49 & 10.98 & (21\%) \\ \hline SH-S & 1684.40 & 0.13 & (14\%) & 537.22 & 2.15 & (15\%) & 4.50 & 9.01 & (31\%) \\ \hline SH-St & 2151.20 & 0.17 & (8\%) & 653.73 & 2.61 & (13\%) & 7.04 & 14.08 & (22\%) \\ \hline SS-N & 1369.75 & 0.11 & (9\%) & 432.29 & 1.73 & (7\%) & 4.89 & 9.79 & (19\%) \\ \hline SS-S & 1543.40 & 0.12 & (9\%) & 479.70 & 1.92 & (12\%) & 7.21 & 14.41 & (24\%) \\ \hline SG-N & 1340.40 & 0.11 & (10\%) & 487.95 & 1.95 & (7\%) & 5.60 & 11.19 & (47\%) \\ \hline SG-St & 1333.25 & 0.11 & (12\%) & 608.29 & 2.43 & (18\%) & 4.41 & 8.81 & (40\%) \\ \hline \end{tabular}
\end{table} 
Table 3: Experimental results. Figure 7: Type of failures: (**a**) peeling failures, (**b**) peeling failures and connector slipping. Figure 11: Connector influence: elastic stiffness. Figure 8: Fabric influence: maximum load. Figure 10: Connector influence: maximum load. Figure 9: Fabric influence: elastic stiffness. Figures 8 and 9 show the impact of the fabric on the maximum load and elastic stiffness of the specimens. The performance of different fabric types remains consistent for both maximum load and stiffness values, regardless of the presence of connectors. Concerning maximum load, the inclusion of connectors significantly enhances the capacity for vegetal specimens, ranging from 13% to 53%. However, there is no notable change for glass fabric. This suggests that the FRCM skin may not reach the cracking strength required to activate the glass fabric, unlike what occurs with vegetal fabrics. Nevertheless, connectors play a beneficial role in maintaining cohesion between materials, activating vegetal fabrics at the achieved level of strain until significantly producing a higher ultimate load. In terms of elastic stiffness, the response of the FRCM sandwich is directly tied to the Young's modulus of the fabric--a stiffer fabric correlates with higher specimen stiffness. Despite glass fabric being seven times stiffer than hemp fabric, this stiffness difference is not prominently reflected in the specimens. This is due to the initiation of non-linear behavior in the core deformation for low values of FRCM strain, minimizing the activation of fabric capacity in the composite and resulting in negligible stiffness differences. Connectors prove efficient in ensuring strain compatibility among components, leading to an increase in stiffness values ranging from 11% to 40%.