# Mechanical Performance of Curved Link-Slab of Simply Supported Bridge Beam
## 4 Sensitivity Analysis of CLS
### Reinforcement Ratio of CLS  
Considering that the reinforcement of the pavement of the link-slab on the SSB bridge is relatively random in the design, this section will analyze the influence of the reinforcement ratio (0.7%, 1.6%, 2.9%, 3.6%, 4.5%) on the mechanical performance of the CLS without changing the pavement thickness. The elastic analysis method is used to calculate the maximum stress on the upper and lower surfaces of the CLS with different reinforcement ratios under various working conditions and load combinations. The results are shown in Figure 13. In the figure, SPDL = second phase dead load, HILL = highway I lane load, RSBF = right span braking force, LSBF = left span braking force, OC = overall cooling 25 \({}^{\circ}\)C, OH = overall heating 15 \({}^{\circ}\)C, NTG = negative temperature gradient, PTG = positive temperature gradient, LC I = load combination I, LC II = load combination II, LC III = load combination III, and LC IV = load combination IV. As noted, with the increase in the reinforcement ratio, the maximum principal tensile stress and principal compressive stress on the upper surface of the CLS decrease, the maximum principal tensile stress of the upper surface under load combination III decreases from 0.97 MPa to 0.59 MPa, and the maximum principal compressive stress on the upper surface under load combination IV decreases from \(-\)4.59 MPa to \(-\)3.83 MPa. The maximum principal tensile stress and principal compressive stress on the lower surface increase. The maximum principal tensile stress of the bottom surface under load combination II increases from 0.44 MPa to 0.77 MPa. The maximum principal compressive stress on the bottom surface under load combination I increases from \(-\)0.89 MPa to \(-\)1.48 MPa. Both the upper and lower surface tensile stresses are less than the concrete's tensile limit. Under the condition that the thickness of the CLS remains unchanged, the stress change amplitude of the CLS under different load conditions is small. Therefore, changing the reinforcement ratio of the CLS has a limited effect on the CLS stress performance. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Numbering** & **Load Condition** \\ \hline
1 & Second Phase Dead Load \\
2 & Highway I Lane Load \\
3 & Vehicle Braking Force (Right Span) \\
4 & Vehicle Braking Force (Left Span) \\
5 & Overall Cooling 25 \({}^{\circ}\)C \\
6 & Overall Heating 15 \({}^{\circ}\)C \\
7 & Negative Temperature Gradient \\
8 & Positive Temperature Gradient \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Load conditions. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline
**Load** & \multicolumn{6}{c}{**Load Safety Factor 1  \\ \hline I & 1.2 & 1.0 & 1.0 & 1.4 & 0.8 \(\times\) 1.4 & 0.8 \(\times\) 1.4 & -  \\ II & 1.2 & 1.0 & 1.0 & 0.8 \(\times\) 1.4 & 1.4 & 1.4 & -  \\ III & 1.2 & 1.0 & 1.0 & 1.4 & 0.8 \(\times\) 1.4 & 0.8 \(\times\) 1.4 & 0.8 \(\times\) 1.7 \\ IV & 1.2 & 1.0 & 1.0 & 0.7 \(\times\) 1.4 & 1.4 & 1.4 & 0.7 \(\times\) 1.4 \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Load combination conditions. As noted, the maximum principal tensile stress of the CLS upper and lower surfaces with the asphalt concrete pavement and the concrete pavement directly increases as the thickness of the pavement increases under the corresponding load conditions. Under load combination I, when the thickness of pavement of CLS increases from 10 cm to 25 cm, the maximum principal tensile stress on the upper surface of the CLS asphalt concrete pavement increases from 0.75 MPa to 2.98 MPa, which is close to the concrete tensile limit value. The maximum principal tensile stress of the upper surface of the CLS concrete pavement is increased from 2.56 MPa to 5.83 MPa when no asphalt layer is applied, which is greater than the tensile limit value of the concrete. Under load combination II, the maximum principal tensile stress of the CLS lower surface increases as the thickness increases from 0.53 MPa to 2.66 MPa, which is less than the tensile limit of concrete.