## 2 Experimental Study
### Experimental Result Analyses
#### 2.6.3 Stress Distribution and Damage Analysis  
The damage of the specimens can be judged based on the analysis of the stress change in the loading process. First of all, we are concerned about the stress of all parts of the steel shear walls with PEC columns when the test reaches the ultimate tensile and compressive strength. Z1, H18, T5, etc. mentioned below are all strain gauge numbers. The number and the arrangement of the strain gauge are as shown in Figure 6.  
1. Stress analysis of PEC columns When the displacement reached 26 mm in 20 th cycle, the infill steel plate had been yielded, but the stress of PEC columns was still small and the safety stock was still high. When loading forward to the right in the positive direction, the left flange of the PEC column near the side of lateral actuator (Z1, Z4, Z5, Z8, Z9, Z12, Z17, Z20, Z21, Z24, Z25, Z28) was in tension and the right flange away from side of lateral actuator (Z2, Z3, Z6, Z7, Z10, Z11, Z18, Z19, Z22, Z23, Z26, Z27) were in compression. When loading forward to the left in the negative direction, on the contrary, the right flange was in tension and the left flange was in compression. Since it  
Figure 9: Skeleton Curve.  
was directly connected with the actuator, the deformation and the stress of left column were obviously greater than that of the right column. The right column had small deformations and stresses because of the buffer function provided by the deformation of the steel plate. According to the test data, the maximum stress of PEC columns and the concrete were 186 MPa and 27 MPa respectively when the steel plate was basically yielding. Therefore, when the steel plate was yielded, PEC columns still had high emergency capacity to ensure the stability of the framework and the occurrence of the yielding dissipation of the steel plate prior to the occurrence of the damage of the whole structure. The concrete stress was uniformly distributed in the normal working state, and the maximum value of concrete was 27.63 MPa. Therefore, the concrete was not damaged, and the stress can be continuously increased.
2. Stress analysis of infill steel plate Based on the analysis of the data, the upper end of the steel plate was pushed by the actuator from left to right when the displacement reaches +26 mm. At this moment, the main diagonal line H17-H24 suffered from the maximum stress that was more than 500 MPa. Meanwhile, we found that the stress of H4 was also large (reaching up to 400 MPa), indicating that the width of diagonal tension strip extended in the direction of the other diagonal line. Besides the stress in the main diagonal region (H18-H23-T5) reaches yield, the counter-diagonal (T11-T15 and T12-T16) also began to yield and dissipate energy. The yield area of the whole steel plate shear wall was about 2/3. Additionally, the stress of the upper part was usually greater than that of the lower part for the strain gages outside of the main diagonal line. Generally speaking, the steel plate has been significantly yielded at the value of +26 mm. When the displacement reached \(-\)29 mm in 21 st cycle, there were results corresponding to the above analysis. In addition, it should be noted that the local stress in the corner is generally larger, while the stress in the middle, such as T16, was smaller.