## 4 Discussion  
The purpose of this study was to compare the performance of the Z-type shear reinforcement and the proposed clip-type shear reinforcement installed at a PC slab's dapped end during the construction stage. The performance characteristics of the two types of shear reinforcement were analyzed through the damage pattern of the dapped end and the strain pattern of the shear reinforcement.  
Figure 11 shows the dapped ends at the end of the test. In ZS-12.8, local cracks appeared near the dapped end. In Specimens C-12.8 and CS-6.4 with clip-type shear reinforcement, no damage was observed at the dapped end. Particularly in CS-6.4, despite the 2.5 times higher loading than that of Specimens ZS-12.8 and CS-12.8, damage was effectively prevented by using clip-type shear reinforcement.  
Figure 12 shows the strain distributions of the unanchored shear reinforcement (S1-S4) and shear reinforcement (Z1 or C1-C2), placed at the dapped end for each region (A-D) of each specimen. The horizontal axis indicates the central displacement of the PC slabs, and the vertical axis indicates the measured strains of the shear reinforcement. In ZS-12.8, the strains for the Z-type shear reinforcement (Z1) were very limited and were close to those of the unanchored shear reinforcement (S1-S4), except for those of Region (C), where the strains of the shear reinforcements were much greater than those of other regions (i.e., Regions (A), (C), and (D)). Owing to the limited anchorage performance of Z-type and unanchored shear reinforcement, the damage was likely to concentrate only on a support without stress distribution to the other supports. Furthermore, in Region (C), the strain of the Z-type shear reinforcement (Z1) was not significantly greater than the unanchored shear reinforcement (S1-S4). This result indicates that the Z-type shear  
Figure 11: Damage at the dapped ends of Specimens (**a**) ZS-12.8, (**b**) CS-12.8, and (**c**) CS-6.4.  
reinforcement demonstrated poor anchorage performance and ineffective load transferring at the dapped end because it was not properly anchored into the concrete without enclosing flexural reinforcement.  
On the other hand, in Specimens CS-12.8 and CS-6.4, the strains of the clip-type shear reinforcement (C1 and C2) were much greater than those of the unanchored shear reinforcement (S1-S4). Furthermore, unlike Specim ZS-12.8 with Z-type shear reinforcement, the strains of all the clip-type shear reinforcements in Regions (A-D) were uniformly distributed, showing greater load distribution capacities in Specimens CS-12.8 and CS-6.4. This was because (1) the clip-type shear reinforcement improved the anchorage performance, owing to the enclosed details, and (2) the clip-type shear reinforcement was arranged in the same direction as the resultant force of the tensile strut (Figure 2b).  
As shown in Figure 12 and Table 5, in the clip-type shear reinforcement in Specimens CS-12.8 and CS-6.4, the strains of C2, measured closer to the loading point, were greater than those of C1, which was measured further away. This result indicates that the clip-type shear reinforcement should be located close to the loading point. Particularly in CS-6.4 under a higher shear force, the measured strains of the clip-type shear reinforcement reached approximately 0.002, which was approximately 80% of the yield strain. This shows the structural efficiency of the diagonally positioned clip-type shear reinforcement.  
Figure 12: Strains for Z-type and clip-type shear reinforcement under loading.