# Experimental Investigation into Failure Modes of Low-Yield-Point Steel Plate Shear Walls
## 2 Horizontal Cyclic Loading Test
### Experimental Results
#### 2.2.1 Description of Failure Phenomenon
The sound was significantly enlarged in the loading process and the frame column was still not yielded with the maximum out-of-plane displacement of 0.24 mm at the center of the infill plate. At the time of the ninth loading level, the maximum reaction force for the actuator forward loading was 537.2 kN with a displacement of 5.3 mm, and that for the reverse loading was 617.3 kN with a displacement of 4.0 mm. There was a continuous muffled sound during the loading process and the middle-lower part of the infill panel started to enter the yielding state, at which time the maximum out-of-plane displacement for the infill panel center was 0.3 mm. When the tenth level was loaded, the maximum reaction force of actuator forward loading was 650.6 kN and the displacement was 6.9 mm, whereas reverse loading was 689.9 kN and the displacement was 5.9 mm. The left flange at the left column base was the pioneer in yielding and the maximum out-of-plane displacement at the center of the shear panel was 0.5 mm. The foundation anchor bolts on the bottom of the structure that were utilized to limit the slip of the bottom plate emerged significantly loose. The forward maximum force was 716.0 kN with a displacement of 8.1 mm, while the reverse maximum load was 751.3 kN with a displacement of 8.5 mm during the eleventh loading level. The right flange of the left column foot appeared yielding and the continuous brittle sound appeared during the loading process. Moreover, the floating rust at the column web was obviously observed to fall off and the infill panel appeared to be slightly  
Figure 13: Deformation at the sixth loading level: (**a**) Infill panel; (**b**) Column base. convex. The maximum out-of-plane displacement at the center of shear panel was 3.7 mm. The deformation of the structure is shown in Figure 14.  
At the twelfth loading level, the maximum reaction force of actuator forward loading was 740.8 kN with the measured displacement of 10.5 mm, and that of reverse loading was 753.9 kN with the displacement of 11.2 mm. The loading process was accompanied by a continuous giant sound and the maximum out-of-plane displacement at the center of the infill panel was 18.4 mm, which indicated that the deformation was more conspicuous compared with the previous loading levels. Meanwhile, there was prominent peeling rust and tensile texture at the web of top beam. The deformation of the member is shown in Figure 15.  
At the thirteenth loading level, the maximum forward force of the actuator was 370.2 kN whose displacement was 10.5 mm, whereas reverse loading was 765.5 kN and displacement was 11.4 mm. The flanges of the column foot on both sides were in the yielding state and a continuous sharp brittle sound was observed during the loading procedure. The forward loading displacement was up to 16.9 mm and the overall bearing capacity of the structure obviously degraded, which was caused by the further expansion of the deformation for the infill panel and the bulging of the upper flange for the top beam at one end of the loading head. Meanwhile, the steel plate connected with the loading head deformed in buckling as a result of the thin plate thickness. By now the maximum out-of-plane displacement of the infill panel reached 25.7 mm and the deformation of different members was indicated in Figure 16, respectively. Figure 14: Falling rust at the web of column. Figure 15: Deformation of the infill panel and top beam for specimen 1: (**a**) Infill panel; (**b**) Top beam. The forward reaction force of the actuator was 685.4 kN and the corresponding displacement was 10.5 mm, whereas the reverse loading was 775.3 kN and displacement was 16.9 mm at the fourteenth loading level. The structural bearing capacity dropped dramatically at the end of this loading and no more load was applied to the specimen through the actuator. Meanwhile, the horizontal low cyclic loading test on specimen 1 was terminated.