## 6 Conclusions  
An experimental study on the effect of the strain rate on the axial compressive behavior FCHC in circular cylinders was conducted and the results are presented and discussed in the current paper. Additionally, a new design-oriented dynamic compressive strength model for FCHC was proposed based on the test database (including the test results from the present study and the available literature). Based on the test results and the comparisons presented above, the following conclusions can be drawn:  
1. The compressive strength and the corresponding strain increase with an increase in the strain rate for both FRP-confined and unconfined high-strength concrete. 2. The increase in the FRP confinement ratio leads to an increase in the dynamic increase factor of FCHC, regardless of the type of FRP jacket. The efficiency of the FRP is not proportional to the FRP confinement ratio. For FCHC with the same type of FRP jacket, the DIF of the three-layer FRP-confined specimen is the smallest and the dynamic increment factor is the largest for the one-layer FRP-confined specimen. This is due to the confinement lag effect in the confined  
Figure 14: Experimental and predicted values of dynamic compressive strength of FCHC. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline  & **Specimen Size** & **FRP** & **FRP** & **Impact Pressure** & **Strain Rate** & \multirow{2}{*}{\(f_{\text{cc},0}\)**(MPa)**} & \multirow{2}{*}{\(f_{\text{cc},0}\)**(MPa)**} & \multirow{2}{*}{\(f_{\text{cc},0}\)**(MPa)**} & \multirow{2}{*}{\(f_{\text{cc},0}\)**(MPa)**} \\ \cline{4-7} \(\mathbf{d}\times\mathbf{h/mm}\) & **Type** & **Thickness** & **(MPa)** & & & & \\ \hline \(150\times 75\) & CFRP & 0.167 & 0.7 & 46.1 & 110.4 & 98.3 & 0.9 \\ \(150\times 75\) & CFRP & 0.167 & 0.7 & 43.3 & 110.4 & 107.5 & 1.0 \\ \(150\times 75\) & CFRP & 0.167 & 0.7 & 48.9 & 110.4 & 97.5 & 0.9 \\ \(150\times 75\) & CFRP & 0.167 & 1.0 & 57.6 & 110.4 & 108 & 1.0 \\ \(150\times 75\) & CFRP & 0.167 & 1.0 & 60.4 & 110.4 & 107.5 & 1.0 \\ [PERSON] et al. & \(150\times 75\) & CFRP & 0.167 & 1.0 & 65.5 & 110.4 & 97.5 & 1.0 \\ \([32]\) & \(150\times 75\) & CFRP & 0.167 & 1.0 & 65.5 & 110.4 & 97.5 & 1.0 \\ \(150\times 75\) & CFRP & 0.334 & 0.3 & 3.2 & 131.1 & 97.5 & 0.7 \\ \(150\times 75\) & CFRP & 0.334 & 0.3 & 3.5 & 131.1 & 96.6 & 0.7 \\ \(150\times 75\) & CFRP & 0.334 & 0.3 & 2.8 & 131.1 & 97.6 & 0.7 \\ \(150\times 75\) & CFRP & 0.334 & 0.7 & 42.2 & 131.1 & 123.1 & 0.9 \\ \(150\times 75\) & CFRP & 0.334 & 0.7 & 40 & 131.1 & 118.3 & 0.9 \\ \hline \(150\times 75\) & CFRP & 0.334 & 0.7 & 36.7 & 131.1 & 124.7 & 1.0 \\ \(150\times 75\) & CFRP & 0.334 & 1.0 & 55 & 131.1 & 131.7 & 1.0 \\ \(150\times 75\) & CFRP & 0.334 & 1.0 & 56.7 & 131.1 & 125.9 & 1.0 \\ \(150\times 75\) & CFRP & 0.334 & 1.0 & 60.6 & 131.1 & 120.8 & 0.9 \\ \(150\times 75\) & CFRP & 0.501 & 0.3 & 3 & 147.4 & 102 & 0.7 \\ \(150\times 75\) & CFRP & 0.501 & 0.3 & 3.1 & 147.4 & 98.1 & 0.7 \\ \(150\times 75\) & CFRP & 0.501 & 0.3 & 2.8 & 147.4 & 97.6 & 0.7 \\ \(150\times 75\) & CFRP & 0.501 & 0.7 & 5.7 & 147.4 & 127.6 & 0.9 \\ \(150\times 75\) & CFRP & 0.501 & 0.7 & 6.5 & 147.4 & 136.5 & 0.9 \\ \(150\times 75\) & CFRP & 0.501 & 0.7 & 4.1 & 147.4 & 124.4 & 0.8 \\ \(150\times 75\) & CFRP & 0.501 & 1.0 & 34.4 & 147.4 & 145.5 & 1.0 \\ \(150\times 75\) & CFRP & 0.501 & 1.0 & 32.2 & 147.4 & 151.6 & 1.0 \\ \(150\times 75\) & CFRP & 0.501 & 1.0 & 34.6 & 147.4 & 143.7 & 1.0 \\ \hline \hline \end{tabular}
\end{table} 
Table 5: _Cont._concrete under dynamic loadings. Namely, dynamic compression leads to failure of the concrete, but the failure is not necessarily developed timely in the FRP jacket. 3. Given the same FRP confinement condition, the DIF of the AFRP-confined high-strength concrete is the largest, indicating that AFRP-confined high-strength concrete has a favorable impact resistance. This is due to the larger FRP hoop strain efficiency for the AFRP. 4. The energy absorption of confined concrete increases with an increase in the strain rate. 5.