## 1 Introduction
### Parametric Analysis Study  
Once the numerical model is validated, parametric analysis studies are conducted to clarify the main influence parameters of the flexural behaviors of PSCB-IUCFRP. At the same time, the numerical model results can be employed to build a database to evaluate the applicability of the prediction models. The dimensions of the beam used for parametric analysis are shown in Figure 7. The main influence parameters for un-bonded prestressed members are considered in this study, including the span-to-depth ratio \(L/d_{\mathrm{P}}\), prestressing reinforcement ratio \(\rho_{\mathrm{P}}\), effective prestressing stress \(\sigma_{\mathrm{pe}}\), concrete strength \(f_{\mathrm{c}}\), and loading types. For the parameter \(L/d_{\mathrm{P}}\), which varies from 11.0 to 24.5, the span length \(L\) is varied, while the cross-section and the effective height \(d_{\mathrm{P}}\) remain unchanged. The segment length is 600 mm, and the number of segments can be determined by the specified span length \(L\). The prestressing reinforcement ratio \(\rho_{\mathrm{P}}\) varies from 0.13% to 0.26% by changing the area of prestressing tendon \(A_{\mathrm{P}}\). The parameter values are listed in Table 2. With the combinations of these parameter values, 162 FE models are built and analyzed. All models were loaded up to failure by displacement control analysis technology. The failure modes are all caused by concrete crushing, and no tendon rupture occurs. The analysis results, including the tendon stress increments \(\Delta\sigma_{\mathrm{P}}\), ultimate displacement at mid-span \(u_{\mathrm{max}}\), and flexural capacity \(M_{\mathrm{u}}\), are listed in Appendix A. The analysis results of a group of numerical beams were plotted in Figures 8-10 as examples, and some basic patterns can be observed as follows, \begin{table}
\begin{tabular}{c c} \hline \hline
**Parameter Name** & **Values** \\ \hline \(L\) (mm) & 3600, 6000, 8400 \\ \(A_{\mathrm{P}}\) (mm\({}^{2}\)) & 253.4, 380.1, 506.8 \\ Effective prestressing stress \(\sigma_{\mathrm{pe}}\) (MPa) & 980, 1225, 1470 \\ Concrete strength \(f_{\mathrm{c}}\) (MPa) & 30, 40, 50 \\ Loading types & Two-point loading, One-point loading \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Parameters and value range of the analyzed beam. Figure 7: Details of the beam used for parametric analysis (unit: mm). 1. Figure 8 shows the load-deflections curves of numerical beams under different loading patterns. The mid-span moment by the applied loads is set as the vertical coordinates in Figure 8 to make comparisons. As the loading patterns shown in Figure 7c, the vertical coordinate in Figure 8 is \(PL/6\) for the two-point loading cases and \(PL/4\) for the one-point loading cases. The loading types have a minor influence on the tendon stress increment and flexural capacity of PSCB-IUCFRP. This phenomenon differs from observations made in the experimental tests on monolithic beams [38,39]. The reason for this is that the plastic region of the segmental beam is concentrated at the failure joint cross-section, regardless of the loading type. In contrast, they are distributed across a monolithic beam. The different deformation modes between segmental and monolithic beams caused the difference. 2. Figure 9 shows the effects of parameters on the tendon stress increment. With the increase in the parameters \(L/d_{\rm p}\), \(A_{\rm p}\), and \(\sigma_{\rm pe}\), the tendon stress increments decrease. The effects of \(f_{\rm c}\) on the tendon stress increments are positive. The sensitivity of tendon stress increments to \(L/d_{\rm p}\) and \(A_{\rm p}\) is more prominent than the other parameters. 3. Figure 10 shows the effects of parameters on the flexural capacity. The parameter \(L/d_{\rm p}\) has a negative correlation with flexural capacity. In comparison, the flexural capacity increases with increasing parameters \(A_{\rm p}\), \(\sigma_{\rm pe}\), and \(f_{\rm c}\).