## 3 Test Results
### Static Test Results and Damage Observations
Representations of Beam_GFRP_PostStr and Beam_CFRP_PostStr at the D\({}_{1}\) damage level are given in Figure 8.  
During the static test conducted after the strengthening of Beam_GFRP_PostStr with GFRP, the first new crack formed at a load value of 43.05 kN (i.e., at 28.71 mm displacement). As the load increased, additional flexural cracks developed. After the strengthening procedure, the maximum load value increased by 14.15% compared to the pre-strengthening state. At a midspan displacement of 62.52 mm, cracks in the concrete cover became more pronounced and extended horizontally to the right. A decrease in load values was observed during the fourth and fifth loading cycles. When the displacement reached 84.32 mm (i.e., at 44.13 kN load), the GFRP layer debonded from the concrete interface, leading to failure. Complete crushing occurred in the concrete of the compression zone, and Beam_GFRP_PostStr exhibited ductile flexural behavior similar to that of Beam_GFRP_PreStr, as shown in the load-displacement curve (see Figure 7). The failure mode of Beam_GFRP_PostStr is presented in Figure 9.  
Figure 8: Bare beams (Beam_GFRP_PostStr and Beam_CFRP_PostStr) at the D\({}_{1}\) damage level. Figure 7: Load–displacement curves of Beam_GFRP_PostStr and Beam_CFRP_PostStr. During the static test performed after the strengthening process of Beam_CFRP_PostStr strengthened with CFRP, the first new crack formed at a load value of 47.74 kN (i.e., at 26.12 mm displacement). As the load increased, additional flexural cracks developed. After the strengthening procedure, the maximum load value for Beam_CFRP_PostStr increased by 41.65% compared to the pre-strengthening state. After reaching a maximum load of 63.22 kN, cracks in the concrete cover became more pronounced and began to propagate to the right. After this point, the load decreased to 55.94 kN (i.e., at 54.32 mm displacement), and debonding of the CFRP with the concrete cover was observed as the failure mode, resulting in a sudden drop in load and the termination of the test (see Figure 7). Beam_CFRP_PostStr exhibited a similar behavior trend to Beam_CFRP_PreStr. The failure mode of Beam_CFRP_PostStr is presented in Figure 6.0 The static test results for all beams are collectively presented in Figure 6.1  
In the table above, F\({}_{\text{cr}}\), F\({}_{\text{y}}\), F\({}_{\text{u}}\), and F\({}_{\text{f}}\) denote the first crack, steel yield, ultimate, and failure loads, respectively, while \(\delta_{\text{cr}}\), \(\delta_{\text{y}}\), \(\delta_{\text{u}}\), and \(\delta_{\text{f}}\) represent their corresponding displacements. In addition, the ductility ratio is calculated and presented in Figure 6.2  
Beam_CFRP_PreStr shows a slightly higher load but a slightly lower displacement at first crack compared to Beam_GFRP_PreStr. This suggests that CFRP provides greater initial stiffness than GFRP, leading to a higher load capacity with less deformation before cracking occurs. Beam_GFRP_PostStr and Beam_CFRP_PostStr, which are bare frames in the undamaged state, exhibit lower loads and displacements at first crack compared to the beams that are strengthened before loading. After the strengthening of pre-damaged beams,