## 3 Results and Analysis of the Tests
### Comparison of Tested Strength to Predicted Strength  
In Figure 7, the predicted strengths of each specimen are shown. For Specimens ZS-12.8 and CS-12.8, if the anchorage performance of the dapped end's shear reinforcement was insufficient, the predicted strength would decrease, owing to a shear failure at the dapped end, as indicated by the green dashed line. On the other hand, if shear failure was prevented at the dapped end, a flexural failure would be expected, as shown by the red, long dashed line in Figure 7a,b. Because Specimens ZS-12.8 and CS-12.8 ultimately failed in flexure at the center (Figure 7a,b and Figure 8a,b), the tested to predicted strength ratios were 1.22 and 1.20, respectively (Table 2 (13)). This indicates that, by using Z-type or clip-type reinforcement, the flexural strengths of the PC slabs at the construction stage could be predicted with an adequate safety margin.  
Figure 10 shows the strain distributions of the wire strands and tensile reinforcement bars of ZS-12.8 under the service load, double the service load, and the ultimate load. At  
Figure 9: Deformed shape of Specim ZS-12.8 under loading.  
the ultimate load, the strains of the wire strands and the tensile reinforcement at the center were greater than the yield strain. The yield strain of strand \(\epsilon_{y}\)\({}^{\prime}\) was calculated as \(0.45\epsilon_{y}\) (\(\epsilon_{y}-0.65\epsilon_{y}+0.1\epsilon_{y}\)), considering the loss of the strain \(0.65\epsilon_{y}\), owing to the introduction of prestress, and the strain due to the short-term loss of \(0.10\epsilon_{y}\). Therefore, in the case of Specimen ZS-12.8, the ductile behavior after flexural yielding was confirmed. Likewise, the strain distributions of CS-12.8 were almost identical to those of ZS-12.8.  
Figure 10: Flexural strain of ZS-12.8 under the following loadings: (**a**) strand at the slab’s center; (**b**) rebar at the slab’s center; (**c**) strand at the slab’s corner; and (**d**) rebar at the slab’s corner.  
In CS-6.4, with the shear-to-span ratio reduced to half (Table 2 and Figure 7c), a shear failure was expected to occur in members other than the dapped end if the shear reinforcement exhibited appropriate performance. However, as shown in Figures 7c and 8c, although a number of flexure shear cracks appeared in the member, the ultimate failure occurred at the center of the PC slab with concrete crushing. In CS-6.4, the strains of the strands and the tensile reinforcing bars were slightly smaller than those of Specimens ZS-12.8 and CS-12.8. However, they exhibited 2.5 to 2.8 times the yield strains, showing ductile behavior similar to that of Specimens ZS-12.8 and CS-12.8. The tested strength to predicted strength ratio was 1.40 (Table 2 (13)).  
None of the specimens suffered the shear failure expected from the predicted strengths, including CS-6.4, with a smaller shear-to-span ratio. This was because the contributions of the unanchored shear reinforcement (straight shear reinforcement and lattice shear reinforcement) were excluded from the strength prediction. Thus, it is necessary to further study the partial contribution of the unanchored shear reinforcement to the shear strengths of the PC slabs.