## 4 Test Results and Discussion
### Dissipated Energy  
An indicative parameter for the assessment of the overall seismic capacity of the tested columns is the dissipated energy in terms of the area of the cyclic hysteretic response of the tested elements. The comparative presentation of the observed dissipated energy of the tested specimens in terms of the area of the hysteretic cycles is presented in Figure 11. In particular, the dissipated energy of the first cycles, the second cycles, and the third cycles of each loading step are presented in Figure 11a-c, respectively. From the comparisons of Figure 11 between the two specimens, it is apparent that the energy dissipating capacity of the pilot specimen is lower than the capacity of the strengthened specimen. Further, it is noted that the differences increase as the loading becomes higher since the damage of the pilot specimen increases excessively compared to the damage of the strengthened one.  
It is noted that the observed improved load capacities of the strengthened specimen compared to the ones of the pilot unstrengthened specimen, as presented in Figures 9 and 10, strongly relate to the improved energy dissipating capacity of the strengthened specimen. It is also emphasized that slippage of the steel bars of the beam has not been observed during the tests due to the well-designed anchorage of the reinforcing bars of the beam in the connection panel and the column of the specimens. Consequently, the an increase in the load capacity in combination with the lack of anchorage slippage, resulted in the increase in energy dissipation.  
Furthermore, it is important that the significant increase in the energy dissipation of the strengthened specimen in the sixth and seventh loading steps, compared to the corresponding ones of the pilot specimen, can partly attributed to the nature of the developing failure mechanisms. In the case of the pilot specimen, the damage was mainly of shear  
\begin{table}
\begin{tabular}{c c c c} \hline \hline  & \multicolumn{3}{c}{**Maximum Loads JC0 VF2X2c/JC0V**} \\ \hline
**Loading Step** & **First Loading Cycle** & **Second Loading Cycle** & **Third Loading Cycle** \\ \hline
1 st & 40.74/39.82 (1.02) \({}^{\star}\) & 38.81/37.03 (1.05) \({}^{\star}\) & 38.10/36.13 (1.05) \({}^{\star}\) \\ \hline
2 nd & 51.58/48.81 (1.06) & 49.68/46.73 (1.06) & 48.77/45.79 (1.07) \\ \hline
3 rd & 61.60/57.92 (1.06) & 58.88/53.44 (1.10) & 57.56/52.21 (1.10) \\ \hline
4 th & 76.31/67.47 (1.13) & 72.21/62.96 (1.15) & 70.30/60.97 (1.15) \\ \hline
5 th & 84.31/72.46 (1.16) & 77.98/66.10 (1.18) & 74.40/62.15 (1.20) \\ \hline
6 th & 84.86/74.02 (1.15) & 70.13/53.54 (1.31) & 60.28/44.95 (1.34) \\ \hline
7 th & 62.07/44.22 (1.40) & 47.45/27.51 (1.72) & 39.63/21.15 (1.87) \\ \hline
8 th & 40.77/failed (-) & 30.66/failed (-) & 25.62/failed (-) \\ \hline \hline \end{tabular} \({}^{\star}\)The ratio of the maximum loads of the two specimens.  
\end{table}
Table 1: Observed maximum loads per loading cycle and ratio of the maximum loads of the strengthened specimen JC0V2X2c over the corresponding maximum loads of the pilot specimen JC0V.  
character and it was localized in the joint panel; on the other hand, in the strengthened specimen, the column and the joint panel remained almost intact and the damage was clearly of flexural character, and it was developed in the beam near the column joint.