## 1 Introduction
Recent studies in the literature have proposed innovative materials and/or application methods to overcome issues such as debonding associated with traditional FRP strengthening techniques. [PERSON] et al. [34] emphasized that early debonding is prevented in R/C beams strengthened with CFRP using the proposed method in the study. Similarly, [PERSON] et al. [35] suggested a plan for the installation sequence of FRP sheets that prevents and delays the debonding of FRP sheets from R/C members. [PERSON] et al. [36] examined the lateral impact behavior of a hybrid FRP-concrete-steel double-skin tubular column (DSTC) using a numerical approach. The results show that hybrid DSTC demonstrates ductile behavior under lateral impact. While the FRP tube does not directly contribute to the impact resistance, it significantly enhances the concrete's ability to withstand impact. [PERSON] et al. [37] conducted experiments to determine the structural performance of beams exposed to high temperatures that were repaired and reinforced with basalt-FRP and carbon-FRP ropes and strips. It was concluded that the beams reinforced with basalt-FRP exhibited a significant increase in load-carrying capacity and were cost-effective. [PERSON] et al. [38] performed experiments to strengthened T-shaped R/C beams using closed-form CFRP ropes. The study indicated that this method, which is straightforward, fast, and requires minimal intervention, enhances the shear capacity of R/C beams. Although numerous studies in the literature have focused on the static behavior of R/C members strengthened with GFRP and CFRP, comprehensive experimental studies examining the static and dynamic behavior of these members strengthened under different damage conditions are quite limited, and there is a need for further research in this area. In this study, the effects of different strengthening materials, namely glass fiber-reinforced polymer (GFRP) and carbon fiber-reinforced polymer (CFRP), on the static and dynamic behavior of reinforced concrete (R/C) beams subjected to cyclic quasi-static loading pattern are investigated. Four identical R/C beams were tested for this purpose in the Structural Mechanics Laboratory at Dokuz Eylul University. Two of the beams were strengthened before any damage was applied, while the other two beams were strengthened after the pre-determined damage was induced. Notably, only one strengthening material was used per beam. This experimental design allows for a comparative evaluation of the influence of GFRP and CFRP applications on both undamaged and pre-damaged beams, contributing to a deeper understanding of optimal strengthening strategies for enhancing or restoring the static and dynamic performance of R/C beams. To observe the effect of these two strengthening materials on the dynamic performance of the beams, vibration datasets from impact hammer tests were recorded using accelerometers placed at five stations on each beam. Subsequently, the beams were subjected to pre-determined damage levels through a four-point bending test. At each damage level, the quasi-static loading was paused, and the loads on the beams were removed to perform the dynamic tests. The recorded dynamic datasets at each damage level were processed using the Enhanced Frequency Domain Decomposition (EFDD) method [39; 40; 41; 42; 43; 44], and the first three vibration modes in both the vertical and horizontal directions were estimated. The changes in the modal frequencies of these modes are presented, demonstrating the effects of the two strengthening materials on the dynamic characteristics of the beams. The study compares multiple vibration modes, identifying notable differences between the performance of GFRP- and CFRP-strengthened beams, thereby clarifying each material's role in restoring or improving static and dynamic properties. In addition to dynamic data, the load-displacement data recorded during the static tests are visualized and interpreted.