## 4 Results and Discussion
### Comparison with the Different Provisions in Design Code
Based on the database constructed in this study, as well as additional data points obtained from in literature [54], the ratios of the predicted results obtained from different methods (including the proposed methods and the provisions in the design codes) to the experimental results \(\beta_{\text{pre}}/\beta_{\text{exp}}\) are presented in Figure 15. It can be seen that most of the ratios \(\beta_{\text{pre}}/\beta_{\text{exp}}\) based on the design codes were plotted below a scale of 1.0. Table 9 summarizes the mean values, coefficient of variation (COV) and IAE of the ratio \(\beta_{\text{pre}}/\beta_{\text{exp}}\) for different methods. The comparison shows that clear differences exist among various design codes. The most liberal is the BS 8100-1:1997 [48], for which the mean value of the ratio \(\beta_{\text{pre}}/\beta_{\text{exp}}\) was 1.35, and the COV and IAE were 0.62 and 30.68%, respectively. The DIN 1045-1:2008 [50] was moderate with the ratio \(\beta_{\text{pre}}/\beta_{\text{exp}}\) of 1.08. Except for these two design codes, the mean values of the ratios based on the other design codes range from 0.35 to 0.79, and the COV and IAE are within the ranges of 0.68-0.84 and 38.55-64.11%, respectively. Despite the conservative nature of the code methods, the predicted values are significantly lower than the experimental results. These indicate the limitations and wide variations between national standards. Meanwhile, it can be known that the mean values of \(\beta_{\text{pre}}/\beta_{\text{exp}}\) for the ANN and SVR models were fairly close to 1.0, and the values of COV and IAE were very low. This indicates that the proposed models can estimate the coefficient of moment redistribution with sufficient precision. In addition, it can also be observed that the predicted results of the additional specimens outside the database agreed well with the experimental results, which demonstrates the applicability of the proposed models. In conclusion, the proposed ANN and SVR models can provide  
\begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Code**} & **Ductility of** & **Concrete Strength** & **Coefficient** \\ \cline{3-4}  & **Reinforcement** & & **Lower than C50/60** & \(\beta\leq 0.36-0.8c/d\leq 0.3\) \\ \hline \multirow{4}{*}{DIN1045-1:2008 [50]} & High ductility & \begin{tabular}{c} Higher than C55/67 and \\ lightweight concrete \\ \end{tabular}  & \(\beta\leq 0.28-0.8c/d\leq 0.2\) \\ \cline{2-4}  & \multirow{2}{*}{Normal ductility} & \begin{tabular}{c} Lower than C50/60 \\ \end{tabular}  & \(\beta\leq 0.36-0.8c/d\leq 0.15\) \\ \cline{3-4}  & & \ \begin{tabular}{c} Higher than C55/67 and \\ lightweight concrete \\ \end{tabular}  & \(0\) \\ \hline \multirow{2}{*}{ \begin{tabular}{c} Fib Model Code \\ 2010 [51] and EN \\ 1992-1-1:2004 [52] \\ \end{tabular}  } & Class B, C or D & \(f_{c^{\prime}}\leq 50\,\text{MPa}\) & \(\beta\leq 0.56-1.25(0.6+0.0014/\varepsilon_{\text{c}\text{c}\text{c}\text{c} \text{an approximate basis for the revision and unification of the moment redistribution provisions in the various codes due to their relative comprehensive consideration of the influential factors as well as their high accuracy. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Method** & **Mean** & **COV** & **IAE** \\ \hline ANN & 1.0335 & 0.1095 & 6.77\% \\ SVR & 0.9952 & 0.0549 & 2.42\% \\ CSA A23.3-14 [47] & 0.6141 & 0.6818 & 52.20\% \\ BS 8100-1:1997 [48] & 1.3474 & 0.6208 & 30.68\% \\ AS 3600-2009 [49] & 0.5834 & 0.7040 & 45.61\% \\ DIN 1045-1:2008 [50] & 1.0761 & 0.8328 & 39.61\% \\ Fib Model Code 2010 [51] & 0.7911 & 0.7496 & 38.55\% \\ EN 1992-1-1:2004 [52] & 0.3485 & 0.8374 & 64.11\% \\ \hline \hline \end{tabular}
\end{table} 
Table 9: Comparisons between ANN, SVR models and methods specified in the design codes. Figure 15: _Cont._