## 1 Introduction
### Numerical Model Validation and Flexural Performances Comparisons  
The flexural behaviors of three different prestressed concrete beams are compared with the numerical model. The configurations of these beams are shown in Table 1. The specimen BC1 reported by [PERSON] et al. (2018) is taken as a case study to verify the effectiveness of the numerical model. BC1 is a PSCB prestressed by internal un-bonded CFRP tendons, and the design details are shown in Figure 4. The other two beams, M-CFRP and S-Steel, are analyzed for comparison. The M-CFRP beam has the same configurations as BC1, except that the beam is monolithic rather than segmental. The S-Steel beam is designed  
Figure 3: Element types in the developed numerical model: (**a**) free-slip tendon element, (**b**) fiber beam element for concrete segment and joint element, (**c**) rigid beam connection element. Figure 2: Simulation scheme of the numerical model: (**a**) PSCB-IUCFRP system, (**b**) numerical model schematic diagram. by replacing the CFRP tendons in BC1 with steel tendons. The comparisons between the results of BC1 and M-CFRP will therefore show the impact of segmental joints on flexural performances. The comparisons between the results of BC1 and S-Steel will display the effects of tendon type. The load-deflection curves are shown in Figure 5a, and the tendon stress increment vs. mid-span deflection curves are shown in Figure 5b. The following comparisons can be made:  
1. Failure in BC1 is caused by concrete crushing. The CFRP tendon is still elastic, consistent with the experimental observations. The calculated values for structural deformation, capacity, and tendon stress all agreed well with the experimental results, verifying the effectiveness of the numerical model. 2. Without the segmental joints, the M-CFRP beam shows a larger flexural capacity than beam BC1. Under the same mid-span deflection, the tendon stress increment of the monolithic beam M-CFRP is larger than that of the segmental beam BC1. The failure mode is changed to CFRP tendon rupture. These differences demonstrate the effects of segmental joints on flexural performance, which should be considered in capacity prediction. 3. For the S-Steel beam, structural failure is caused by the steel tendon yielding and then concrete crushing, which is different from the BC1 beam. The effects of the tendon type are non-negligible when predicting flexural capacity. 4. Figure 5b shows that the relationship between tendon stress increment and mid-span deflection is almost linear before tendon failure. The slope of the linear relationship is affected by the tendon type and segmental joints. The stress increments of steel tendons in the beam S-Steel are more significant than the CFRP tendon in the beam BC1 due to the steel tendon's higher elastic modulus than the CFRP tendon. The comparisons between the M-CFRP and BC1 beams show that the tendon stress increments in the segmental beam are lower than the monolithic one. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Name** & **Structural Type** & **Tendon Type** & **Effective Tendon Stress (MPa)** \\ \hline BC1 [21] & Segmental & CFRP & 818 \\ M-CFRP & Monolithic & CFRP & 818 \\ S-Steel & Segmental & Steel & 818 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Configuration of the contrasting beams. Figure 4: Design details of specimen BC1 (unit: mm). 5. The sectional curvature distribution and deflection curves along the beam length are extracted from the analysis results to address the effects of segmental joints on the tendon stress increment, as shown in Figure 6. We find that the plastic deformations only occur at the mid-span joint section, and the other regions are almost elastic. However, the plastic deformations are distributed within the flexural span for the monolithic beam M-CFRP. The un-bonded tendon elongation is associated with the whole beam deformation, causing the differences in tendon stress increments between the monolithic and segmental beams.