## 3 Experimental Results
### Analysis and Comparison of Experimental Results
#### 3.2.5 Strain Gauges Attached to the Integrated Member  
Figures 12 and 13 show the stresses measured with strain gauges attached to the integrated member. The stress value was calculated by multiplying the elastic modulus (203,000 MPa) with the strain measured using the strain gauge. The loci of Figures 12 and 13 contain the peak loads from the first cycle of each phase of the cyclic loading.  
The strain gauge, shown in Figure 12, was attached to the vertical direction at a height of 1220 mm (\(h_{0}+h_{1}\) shown in Figure 2). The measured stresses exceed the yield strength at high lateral drift ratios in the stud-reinforced specimens. In the IP specimen, the measured stresses increase until local buckling occurred, but after the local buckling, the stresses are irregular. The IP-IS specimen exhibits higher and more stable stresses at a lateral drift ratio of 2.5% or more with local buckling than the IP-OS specimen. The reason for this tendency is that the IP-IS specimens behave in a combined manner with the integrated member and the stud, but the IP-OS specimens do not. The IP specimen shows a greater measured stress value at a lateral drift ratio of 1.5% than those of the stud-reinforced specimens. This is because the IP specimen has a smaller cross section than the stud-reinforced specimen.  
Figure 11: Variation in the energy dissipation per load cycle with drift ratio.  
Figure 12: Variation in the stress with drift ratio measured using the strain gauge attached to the vertical direction at a height of 1220 mm at the center of the flange of the integrated panel.  
The strain gauges, shown in Figure 13, were attached to the vertical direction at a height of 400 mm. Below a drift ratio of 1.0%, the stress distribution differs from the normal stress distribution for bending moment in the balanced flipped channel. Since the two columns with two hinged ends were installed on the left and right sides of the specimen to induce shear behavior, a tensile stress occurred at a point where the sectional width was 480 mm, which is where a compressive stress had to occur. These results are similar to the behavior of deep beams, because of the large width of the deep beam and the integrated member. Local buckling occurred at a 1.5% drift ratio, resulting in an irregular stress distribution.  
Figure 13 also shows that local buckling occurs before sufficient stress is exerted on the section where local buckling of the integrated member occurs. The IP specimen temporarily lost their load due to local buckling, but the peak load increases at higher lateral drift ratios.  
In the IP-IS and IP-OS specimens, local buckling occurs before sufficient stress is exerted on the section where local buckling occurred, similar to the IP specimen. However, as shown in Figure 6, the load tends to decrease after the local buckling of the IP-IS and IP-OS specimens. As listed in Table 3, the yield strengths \(V_{y}\) of the stud-reinforced specimens (IP-IS and IP-OS) are 31% and 37% lower than the nominal strength \(V_{n,USI}\). Therefore, it is judged that other forces acted on the reinforcing studs in addition to the axial stress due to bending.