## 3 Results and Discussion
### Analysis of Recorded Deflections  
Special attention in this research is paid to the analysis of deflections of continuous beams. The disposition of the control beam, before and after deformation, is shown in Figure 9.  
A comparative analysis of the deflection of reinforced beams was performed in relation to the control, unreinforced beam and the dependence curves between the load, and the deflection of the section in the middle of the span are shown in Figure 10.  
On the curves, in general, characteristic zones can be observed when applying the load, and these are:  
* Zone before emergence of the cracks, where the relation between the load and displacement is linear,
* Zone after emergence of the cracks, and before the yield of steel, crushing of concrete or debonding of the strengthening system, where the relationship between the load and displacement is non-linear; and
* Zone after the yield of steel, crushing of concrete or debonding of the strengthening system until the cross-section failure. The behavior of the tested beams until the emergence of the first cracks is almost identical, after which the strengthened beams exhibit higher rigidity and higher load-bearing capacity. With the B-EC beam, the dependence curve is generally linear even after \begin{table}
\begin{tabular}{c c c c c c} \hline \hline  & **Beam Label** & \
\begin{tabular}{c} **Tensioned Steel** \\ **Reinforcement** \\ \end{tabular} &
\begin{tabular}{c} **Compressed** \\ **Concete** \\ \end{tabular} & **FRP** & **Deflection** \\ \hline \multirow{6}{*}{Section I} & B–con & SG1 & SG4 & - & LVDT1 \\  & B–G1 & SG1 & SG4 & - & LVDT1 \\  & B–G2 & SG1 & SG4 & SG6 & LVDT1 \\  & B–G3 & SG1 & SG4 & SG6 & LVDT1 \\  & B–C & SG1 & SG4 & SG6 & LVDT1 \\  & B–EC & SG1 & SG4 & SG6 & LVDT1 \\  & B–con & SG2 & D1 & - & - \\  & B–G1 & SG2 & D1 & SG6 & - \\  & B–G2 & SG2 & D1 & - & - \\  & B–G3 & SG2 & D1 & SG7 & - \\  & B–C & SG2 & D1 & SG7 & - \\  & B–EC & SG2 & D1 & SG7 & - \\  & B–con & SG3 & SG5 & - & LVDT2 \\  & B–G1 & SG3 & SG5 & - & LVDT2 \\  & B–G2 & SG3 & SG5 & SG7 & LVDT2 \\  & B–G3 & SG3 & SG5 & SG8 & LVDT2 \\  & B–C & SG3 & SG5 & SG8 & LVDT2 \\  & B–EC & SG3 & SG5 & SG8 & LVDT2 \\ \hline \hline \end{tabular}
\end{table} 
Table 7: Position of strain gauge tapes (SG) and linear variable displacement transducers (LVDT) dilatometers in Sections I, II and III of the tested beams. the appearance of cracks, which indicates a small deformability but also the higher ductility of this beam. Figure 11a shows the comparison of the maximum load capacity of the tested beams. The load-bearing capacity of all beams was increased:  
* For beams strengthened with GFRP bars, by the NSM method, the increase in load-bearing capacity was 22-67% depending on the position of the reinforcement, with the largest increase in load-bearing capacity of beam B-G3 when the strengthening is both above the middle support and in both spans of the beam. * In the case when beams are strengthened with CFRP bars by the NSM method both above the middle support and in both spans of the continuous beam (B-C beam), the increase in load-bearing capacity is 82%. * For beams strengthened with CFRP tapes of the same axial stiffness as CFRP bars, by the EB method (B-EC beam) the increase of the load-bearing capacity compared to the B-C beam is lower, and it amounts to 50%. Figure 10: Mid-span deflection diagram for different strengthening variants. Figure 9: Disposition of the control beam: (**a**) Before loading; (**b**) Under loading. Figure 11b shows maximum deflections at midspans at the moment of failure of the tested beams. It can be noticed that the maximum deflections of beams B-G1 and B-G2 increase with the increasing failure force, while in other strengthened beams the deformability is lower, which is shown by one of the most important parameters--the ductility index. The ductility index in beams strengthened with GFR reinforcement (B-G1, B-G2 and B-G3) has satisfactory values (ID = 4 \(\div\) 5), while in beams strengthened with CFRP reinforcement the ductility is very small (ID = 1.5).