## 2 Finite Element Analysis Modeling and Validation
### Finite Element Model Validation  
To verify the correctness of the finite element model of the temperature field, ABAQUS software was used to establish the finite element analysis model of the RPC column, which was compared and analyzed with the fire-resistance limit test of the steel-reinforced RPC column in the literature [30]. The detailed parameters of the specimen are shown in Table 1. The selection of thermal parameters such as the specific heat capacity and thermal conductivity of steel and concrete materials is shown in Section 2.2. The thermal convection and thermal radiation coefficients of the fire-exposed surfaces are selected as 25 W/(m\({}^{2}\)\({}^{\circ}\)C) and 0.6, respectively, and the two ends of the columns are fully fixed. The simulation results of the temperature field of the RPC columns and the comparisons with the experimental values are shown in Figure 1. In Figure 1, the horizontal axis is the time of fire in the temperature field simulation in this study and the fire limit test of reinforced RPC columns in the literature [30]. And the vertical axis is the temperature value in the temperature field simulation in this study and the test in the literature [30]. Through our comparison, we found that when the temperature is below 300 \({}^{\circ}\)C, the experimental value of the temperature field is almost identical to the simulated value. The maximum time difference between the experimental and simulated values is 30 s with an error of less than 15% in the temperature range of 300 \({}^{\circ}\)C. As the temperature continues to increase, the error between the two rises slightly. The simulation results are slightly \begin{table}
\begin{tabular}{c c c c c c} \hline
**Column Name** & **Column Height (mm)** & **Section Width (mm)** & **Protective Layer Thickness (mm)** & **Longitudinal Bar Diameter (mm)** & **Hoop Diameter (mm)** & **Axial Pressure Ratio** \\ \hline RPC Column & 1200 & 200 & 25 & 22 & 8@60 & 0.25 \\ \hline \end{tabular}
\end{table} 
Table 1: Column size parameters. different from the test values, mainly due to two factors. One is that there are a number of influencing factors in the high-temperature test process, such as ventilation conditions, air humidity, and many other factors that cause variability in the experimental results. The second is that the finite element model does not simulate the escape of water vapor from the concrete well, and there are differences in the values of the selected thermal parameters and other values with the test material. The error between the experimental and simulated values gradually decreases and converges after the temperature is higher than 500 \({}^{\circ}\)C. Combined with Figure 1 as a whole, it can be seen that the simulated value agrees well with the experimental value, thus indicating that the established temperature field model is reliable. The finite element analysis of the RPC column explosion resistance test in the literature [31] was performed to verify the correctness of the established finite element explosion model of the RPC column. The geometric dimensions of the RPC column are shown in Table 2, and the arrangements of longitudinal reinforcement and hoop reinforcement are shown in Figure 2 below, with the two ends of the column fully fixed. The contrast between the simulation results of the RPC column span-to-span deformation and the test results is shown in Figure 3, where the horizontal axis represents the time of application of the blast load, and the vertical axis represents the mid-span displacement of the RPC column. The peak deformation measured in the deformation test is 1.96 mm, and the peak deformation obtained from the simulation is 1.84 mm, with a difference of 6.1%. At the same time, there is a certain error between the simulated and experimental values, and there are many factors that cause this error. First, in the actual explosion process, the pressure distribution of the components on the explosion surface is