## 3 Results and Discussion
### Failure Modes
#### 3.1.3 Specim LAPC-2  
The failure process of the LAPC-2 specimen was basically the same as that of LAPC-1, but the difference was that the cracking displacement of the grouting layer and the ultimate failure displacement of LAPC-2 were larger, which were the loading level of 20 mm and 54 mm, respectively.  
The failure of the root of the L-shaped shear wall and the grouting joint is shown in Figure 7. It can be seen that concrete crushing and rebar buckling occurred in the straight-edge members of the prefabricated and cast-in-place specimens, and the concrete damage of this prefabricated specimen was mainly concentrated in the range from the bottom of the wall to 300 mm higher than the top of the sleeve. However, the damage of the cast-in-place specimen occurred at the bottom of the wall, which was manifested as concrete crushing and spalling, and reinforcement buckling above the stirrup densification area (i.e., 220 mm to 320 mm above the foundation beam). Compared with the cast-in-place specimen, the concrete above the sleeve was crushed in the prefabricated wall, and then the concrete outside the sleeve was peeled off, but the sleeve was not significantly damaged. Eventually, the rebars above the sleeves of the precast wall buckled, indicating that the wall had reached its limit state. The reason was that the APC sleeve restrained the deformation of the rebar and grout, which made the weak section move up to the top surface of the sleeve. Similarly, reference [25] showed that concrete damage of straight prefabricated shear walls was mainly concentrated in the range from the bottom of the wall to 300 mm higher than the top of the sleeve, indicating that this range was the weak part of the prefabricated specimen. It can be seen from Figure 7a that the spalling of the concrete outside the sleeve was more serious at the limit state. This was mainly due to manufacturing error, which made the spacing of stirrups within the height range of the sleeve locally larger, and the deformation capacity of the outer concrete was poor. Compared with this test, in the reference [25], stirrups with a spacing of 50 mm were arranged within the height range of the sleeve in the prefabricated wall, and the concrete outside the sleeve was only partially damaged at the limit state. Therefore, proper densification of stirrups within the height range of the sleeve can effectively improve the bonding performance of the external concrete.  
At the limit state, the grouting material of the joint on the left and right sides of the prefabricated wall was crushed and peeled off, while the grouting material of the joint in the middle of the specimen was not significantly damaged, as shown in Figure 7b. The lower surface of the precast wall (that is, the upper surface of the grouting joint) was not chiseled, forming a horizontal through crack, but the wall did not experience obvious shear slip. Since the grouting material in the sleeve and the joint were poured at the same time to form a whole, which played a role similar to the occlusal teeth, the shear bearing capacity of the joint was improved. The lower surface of the joint of the prefabricated wall and the interface of the bottom of the cast-in-place wall (both of which had been chiseled) did not have obvious cracks, indicating that the chisel can effectively improve the bonding strength between the grouting material and the concrete. Similarly, the surface of the concrete at the joint was chiseled to effectively avoid premature cracking of the joint surface in straight prefabricated walls [25]. In addition, the rebar in the sleeve was not pulled out at the limit state, and the sleeve had no obvious deformation, indicating that the sleeve had good mechanical properties.