# Design Procedure of a Mono-Anchor Head for 2360 MPa High-Strength Steel Strand
## 7 Summary and Conclusions  
In this paper, we present a design procedure to determine the design parameters that satisfy the safety performance criteria of anchor heads anchoring high-strength strands. Performance criteria for evaluating mono-anchor heads were presented. Next, the mechanical behavior characteristics of the mono-anchor head were identified, and finite element analysis was performed to quantify it numerically. A static load test was conducted so that the analysis model reflected the actual behavior, and a highly reliable analysis model was modeled through the material test of the anchor head. A parametric analysis was performed according to the diameter, internal inclination angle, and yield strength of the material, which are considered major parameters in designing the anchor head, and the relationship between stress and plastic strain was established. The results of this study are summarized as follows:  
1. It is reasonable to evaluate the permissible performance criteria of a mono-anchor head using the plastic hoop strain. Accordingly, in this paper, the permissible performance  
Figure 24: Procedure to determine the design parameters of a mono-anchor head.  
criteria were evaluated using the plastic hoop strain at the top of the wedge hole in the anchor head.
2. Among the anchoring device components, the difference in inclination angle between the wedge and the anchor head is the main cause of stress concentration at the top of the wedge hole, and finite element analysis was performed to quantify it numerically.
3. In the static load test conducted prior to finite element analysis, the steel used for the anchor head was carburized 42 CrMo4. When modeling for this analysis, it is effective to separate the hardened layer and the inner layer of the material and apply each strength.
4. The concentration of the load applied to the top of the wedge hole was calculated by analyzing the behavior of the carburized 42 CrMo4 anchor head with elastic response according to the configuration based on the finite element analysis. Through this, the stress of the element located at the top of the wedge hole can be calculated.
5. The plastic hoop strain at the top of the wedge hole, which is the performance criterion, was established in relation to the stress exceeding the yield strength. Using this relationship, the plastic hoop strain can be calculated when the anchor head diameter, internal inclination angle, and yield strength are determined.
6. A design simplification procedure was proposed to determine the design parameters.  
According to the design method developed in this paper, the following two advantages can be expected. (1) When the selection of steel strength is limited, the configuration of the anchor head can be easily determined. (2) When the construction space of the anchor head is limited, the yield strength can be easily determined.  
Conceptualization, S.-W.K. and J.-K.K.; methodology, S.-W.K.; software, S.-W.K.; validation, S.-W.K. and J.-K.K.; formal analysis, S.-W.K.; investigation, S.-W.K.; resources, J.-K.K.; data curation, S.-W.K.; writing--original draft preparation, S.-W.K.; writing--review and editing, J.-K.K.; visualization, S.-W.K.; supervision, J.-K.K.; project administration, S.-W.K. All authors have read and agreed to the published version of the manuscript.  
This study was supported by the Research Program funded by SeoulTech (Seoul National University of Science and Technology).  
Not applicable.  
The authors declare no conflict of interest.