# Shear Resistance Assessment of the Y-Type Perfobond Rib Shear Connector under Repeated Loadings
## 4 Shear Behavior under Repeated Loads
### Residual Shear Performance after Repeated Loads
#### 4.1.2 Residual Ductility  
The ductility degradation of the Y-type perfobond rib shear connectors due to the repeated loads was evaluated by comparing with the results of monotonic loading tests. In the both cases, the ductility was evaluated using the method shown in Figure 5. In Table 12, \(\delta_{u}/\delta_{90}\) after repeated loads do not show noticeable changes. The lowest values of \(\delta_{u}\), \(\delta_{90}\), and \(\delta_{u}/\delta_{90}\) are marked. Even though the lowest values are found from the load types 1-3, in which 1460 kN loads are included, the characteristic values are not much worse than those of the monotonic tests, which are also marked. It is concluded that the ductility deterioration may not be considerable under the repeated loads with the intensity up to 65% of the ultimate shear strength. However, the ductility performance should be examined when the number of repeated loads increases considerably. \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multicolumn{2}{c}{**Monotonic Loading Tests Only**} & \multicolumn{5}{c}{**Monotonic Loading Tests after Repeated Loading Tests**} \\ \hline
**Specimen** & \(\delta_{u}\)**(mm)** & \(\delta_{u}\)**(mm)** & \(\delta_{u}\)**/\(\delta_{90}\)** & **Specimen** & **Load Type** & \(\delta_{u}\)**(mm)** & \(\delta_{u}\)**(mm)** & \(\delta_{u}\)**(mm)** & \(\delta_{u}\)**(\(\delta_{90}\)**)** \\ \hline SD400-D16-1 & 28.7 & 3.2 & 9.0 & SD400-D16-1R & Type 1 & 44.7 & 2.7 & 16.5 \\ \hline SD400-D16-2 & 37.5 & 4.1 & 9.2 & SD400-D16-2R & Type 2 & 24.4\({}^{\star}\) & 3.2 & 7.5 \\ \hline SD400-D16-3 & 35.4 & 27.\({}^{\star}\) & 13.2 & SD400-D16-3R & Type 4 & 24.5 & 3.5 & 6.9\({}^{\star}\) \\ \hline Average & 33.9 & 3.1 & 10.5 & Average & & 31.2 & 3.2 & 10.3 \\ \hline SD400-D19-1 & 45.6 & 3.9 & 11.6 & SD400-D19-1R & Type 3 & 36.7 & 5.2 & 7.0 \\ \hline SD400-D19-2 & 34.2 & 4.6 & 7.5 & SD400-D19-2R & Type 4 & 34.4 & 4.4 & 7.9 \\ \hline SD400-D19-3 & 45.7 & 5.0 & 9.1 & SD400-D19-3R & Type 5 & 45.0 & 4.9 & 9.2 \\ \hline Average & 41.8 & 4.5 & 9.4 & Average & & 38.7 & 4.8 & 8.0 \\ \hline SD500-D16-1 & 24.9 & 4.0 & 6.3\({}^{\star}\) & SD500-D16-1R & Type 3 & 26.8 & 3.6 & 7.5 \\ \hline SD500-D16-2 & 23.8\({}^{\star}\) & 3.0 & 7.9 & SD500-D16-2R & Type 4 & 39.4 & 3.7 & 10.7 \\ \hline SD500-D16-3 & 41.0 & 3.0 & 13.5 & SD500-D16-3R & Type 5 & 33.9 & 3.5 & 9.6 \\ \hline Average & 29.9 & 3.3 & 9.2 & Average & & 33.4 & 3.6 & 9.3 \\ \hline SD500-D19-1 & 50.5 & 5.1 & 9.8 & SD500-D19-1R & Type 3 & 25.1 & 2.0\({}^{\star}\) & 12.9 \\ \hline SD500-D19-2 & 56.1 & 4.6 & 12.3 & SD500-D19-2R & Type 4 & 45.1 & 5.3 & 8.5 \\ \hline SD500-D19-3 & 45.4 & 6.0 & 7.5 & & & & \\ \hline SD500-D19-4 & 55.9 & 4.4 & 12.8 & & & & \\ \hline Average & 52.0 & 5.0 & 10.6 & Average & & 35.1 & 3.6 & 10.7 \\ \hline SD500-D22-1 & 46.7 & 5.9 & 7.9 & SD500-D22-1R & Type 5 & 52.5 & 4.8 & 10.9 \\ \hline SD500-D22-2 & 47.9 & 7.0 & 6.9 & & & & \\ \hline Average & 47.3 & 6.4 & 7.4 & Average & & 52.5 & 4.8 & 10.9 \\ \hline \multicolumn{2}{c}{\({}^{\star}\) Lowest value.} & & & & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 11: Shear resistance degradation by load types. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Load Type** & **Specimen (Repeated)** & **Residual Ratio** & **Averaged Reduction Ratio** \\ \hline Type 1 & SD400-D16-1R & 0.959 & 0.041 \\ \hline Type 2 & SD400-D16-2R & 0.954 & 0.046 \\ \hline Type 3 & SD400-D19-1R & 0.935 & 0.071 \\ \multicolumn{2}{c}{SD500-D16-1R} & 0.933 \\ \multicolumn{2}{c}{SD500-D19-1R} & 0.918 \\ \hline Type 4 & SD400-D16-3R & 0.982 & 0.023 \\ \multicolumn{2}{c}{SD400-D19-2R} & 0.975 \\ \multicolumn{2}{c}{SD500-D16-2R} & 0.981 \\ \multicolumn{2}{c}{SD500-D19-2R} & 0.970 \\ \hline Type 5 & SD400-D19-3R & 0.979 & 0.031 \\ \multicolumn{2}{c}{SD500-D16-3R} & 0.971 \\ \multicolumn{2}{c}{SD500-D22-1R} & 0.953 \\ \hline \hline \end{tabular}
\end{table} 
Table 12: Characteristic values of displacement ductility according to load conditions.