# Punching Shear Stress in Post-Tensioned Transfer Plate of Multi-Story Buildings
## 2 Literature Review
The results showed that for the girder designed with ACI code, the maximum shear force was 1.44 times the design shear force and 1.19 times the design force with the strut-tie model. This result shows that the design method, which simply replaces the wall into equivalent load without considering the contribution of the upper shear wall, can lead to excessive design. Additionally, a number of studies have been conducted on numerical modeling methods in the design of transfer structures [10; 11; 12; 13; 14]. [PERSON] and [PERSON] [10] and [PERSON] and [PERSON] [11] analyzed the numerical modeling method of continuous transfer girders and shear walls using finite element analysis. By analysis under gravity load, this study showed that the interaction zone exists in the shear wall below a height equal to \(L\), which is the span of the transfer girder. In the interaction zone, it was shown that the stress is transferred to column through the arching action (Figure 3), and the behavior and failure mode of the transfer structure can be affected by the location of the upper shear wall. Thus, it was indicated that the modeling of upper shear wall is important in the numerical model of transfer structures. Figure 2: Analysis method for the design of transfer girder (redrawn from [PERSON] and [PERSON] [9]). (**a**) Strut-tie model and (**b**) Line element model. [PERSON] et al. [12] similarly carried out analytical studies on the modeling of transfer girders and upper shear walls. As a result of the analysis of the modeling height as a variable under gravity load, the shear and stress distribution of the transfer girder model, where the height of the upper shear wall was 1.5 times the span of the shear wall, was shown to be similar to complete model. [PERSON] and [PERSON] [13] and [PERSON] and [PERSON] [14] also carried out studies on the modeling method on transfer girders. The detailed analysis using finite element analysis and two- and three-dimensional analyses were compared to each other. Based on the comparison of the maximum bending moment due to gravity and lateral loads, the three-dimensional analysis showed the closest results to the detailed analysis. It was also found that the analytical method of replacing the upper shear wall with equivalent load shows a similar distribution pattern of shear force and moment compared with the detailed analysis results. However, the values are overestimated, which may lead to an uneconomical design. In addition, experimental and analytical studies have also been conducted, where the transfer floor is located at higher levels. [PERSON] et al. [15] carried out the shaking table test for the scaled model of the buildings with transfer story at the fifth, sixth or ninth floor, respectively. To analyze dynamic behavior, the fundamental period of each model was measured. For the building with a transfer story located at the fifth, seventh or ninth floor, the fundamental period was measured as 9.3 s, 9.6 s or 7.9 s, respectively, for the x-direction, and 8.3 s, 9.3 s or 7.3 s, respectively, for the y-direction. As a result of measuring the story shear force and the inter-story drift ratio under three ground motions, no obvious tendency was observed. It also was found that the increase in the height of the transfer story changes the behavior of the building, but the obvious tendency, such as consistent increase or decrease in behavior, was not clear. A review of studies related to the transfer structure showed a lack of research on the modeling method of post-tensioned transfer plate and the punching shear behavior of the transfer plate. In particular, the behavior of the post-tensioned transfer plate under lateral load had not yet been studied. A number of studies on transfer structure showed that the method of replacing the superstructure with load could lead to excessive design. Therefore, in this study, the modeling method for the post-tensioned transfer plate, especially in point of view of punching shear design, was assessed.