## 3 Experimental Results  
### Steel Material  
The mechanical properties of the steel obtained by uniaxial tensile tests after different corrosion intervals are shown in Table 3. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Thickness** & **Corrosion** & **Weight Loss** & **Yield Stress** & **Ultimate Stress** & **Elongation** & **Elasticity Modulus** \\ (**mm)** & **Time (h)** & **Ratio (\%)** & \(f_{\mathbf{y}}\) (MPa)** & \(f_{\mathbf{u}}\) (MPa) & \(\delta\) (\%) & \(E\)s (MPa) \\ \hline \hline \multirow{8}{*}{6.5} & 0 & 0 & 335.23 & 482.81 & 32.66 & 206,386 \\  & 240 & 1.32 & 330.54 & 486.54 & 32.31 & 206,126 \\  & 480 & 2.54 & 332.86 & 479.55 & 30.14 & 205,003 \\ \cline{1-1}  & 960 & 5.15 & 320.13 & 464.66 & 30.68 & 199,548 \\ \cline{1-1}  & 1440 & 6.99 & 309.52 & 456.71 & 29.13 & 198,368 \\ \cline{1-1}  & 1920 & 8.99 & 308.39 & 450.32 & 28.34 & 190,684 \\ \cline{1-1}  & 2400 & 11.35 & 303.17 & 448.65 & 28.07 & 186,684 \\ \cline{1-1}  & 2880 & 13.51 & 291.66 & 441.94 & 24.76 & 180,984 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Mechanical properties of steel. Figure 5: Test loading setup. Figure 6: Specim loading scheme. As can be seen in the above table, the deterioration of mechanical properties increased with the increase of the steel corrosion time. The longer the corrosion time of the steel, the greater the weight loss ratio. Additionally, the thicker the steel workpiece was, the less the weight loss ratio was. As the weight loss ratio increased, the mechanical properties of steel deteriorated continuously. The relationship of the weight loss ratio and the mechanical properties of the steel was obtained through the linear regression analysis of the above data. The fitting results and the regression expression are shown in Figure 7 and Equation (2), respectively. \[\left\{ \begin{array}{l}f_{y}^{\prime}/f_{y}=1-0.9721D_{\mathrm{w}}\\ f_{u}^{\prime}/f_{u}=1-0.9862D_{\mathrm{w}}\\ \delta^{\prime}/\delta=1-1.6257D_{\mathrm{w}}\\ E_{\mathrm{s}}^{\prime}/E_{\mathrm{s}}=1-0.9019D_{\mathrm{w}}\end{array} \right. \tag{2}\]  
where,  
\[f_{y}^{\prime}=F_{y}^{\prime}/A \tag{3}\]  
\[f_{\mathrm{u}}^{\prime}=F_{\mathrm{u}}^{\prime}/A \tag{4}\]  
where \(f_{y}\), \(f_{\mathrm{u}}\), \(\delta\), \(E_{\mathrm{s}}\) are yield strength, unlimited strength, elongation and elasticity modulus of uncorroded steel respectively, \(f_{y}^{\prime}\), \(f_{u}^{\prime}\), \(\delta^{\prime}\), \(E_{\mathrm{s}}^{\prime}\) are yield strength, unlimited strength, elongation and elasticity modulus of corroded steel respectively, \(F_{y}^{\prime}\), \(F_{u}^{\prime}\) are yield and unlimited tension of corroded steel respectively, and \(A\) is section area of uncorroded steel samples. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Thickness** & **Corrosion** & **Weight Loss** & **Yield Stress** & **Ultimate Stress** & **Elongation** & **Elasticity Modulus** \\ (mm) & **Time (h)** & **Ratio (\%)** & **\(f_{y}\) (MPa)** & **\(f_{u}\) (MPa)** & **\(\delta\) (\%)** & **\(E_{\mathrm{s}}\) (MPa)** \\ \hline \multirow{8}{*}{9} & 0 & 0 & 341.38 & 493.62 & 30.79 & 205,881 \\  & 240 & 0.93 & 344.23 & 488.64 & 30.52 & 204,111 \\  & 480 & 1.81 & 336.54 & 481.38 & 30.24 & 200,684 \\  & 960 & 3.72 & 330.58 & 478.55 & 29.37 & 199,844 \\  & 1440 & 5.02 & 324.84 & 476.64 & 28.46 & 192,336 \\  & 1920 & 6.49 & 322.16 & 464.22 & 28.10 & 191,558 \\  & 2400 & 8.24 & 322.33 & 467.21 & 26.37 & 188,955 \\  & 2880 & 9.76 & 311.94 & 460.27 & 25.13 & 185,684 \\ \hline \multirow{8}{*}{14} & 0 & 0 & 326.64 & 481.58 & 34.17 & 204,768 \\  & 240 & 0.59 & 325.21 & 488.64 & 33.84 & 201,335 \\ \cline{1-1}  & 480 & 1.13 & 322.18 & 479.68 & 33.28 & 202,351 \\ \cline{1-1}  & 960 & 2.39 & 320.44 & 473.26 & 32.82 & 190,667 \\ \cline{1-1}  & 1440 & 3.19 & 315.62 & 474.62 & 32.23 & 197,684 \\ \cline{1-1}  & 1920 & 4.17 & 312.58 & 466.63 & 31.81 & 195,558 \\ \cline{1-1}  & 2400 & 5.26 & 305.11 & 465.21 & 30.67 & 194,668 \\ \cline{1-1}  & 2880 & 6.04 & 302.11 & 459.86 & 28.89 & 191,334 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: _Cont_.