| Title |
Variation of Concrete Breakout Strength of Concrete Expansion Anchors Post-Installed on Uncracked Low Strength Concrete according to Installation Torque Level |
| Authors |
조성국(Cho, Sung Gook);소기환(So, Gihwan);이정희(Lee Jeonghee);이홍표(Lee, Hongpyo) |
| DOI |
https://doi.org/10.12652/Ksce.2026.46.1.0001 |
| Keywords |
콘크리트 확장앵커; 설치토크; 파괴모드; 파괴강도; 인장성능 Concrete expansion anchor; Installation torque; Failure mode; Breakout strength; Tensile performance |
| Abstract |
Various types of equipment are installed in industrial facilities, including nuclear power plants (NPPs). In these facilities, concrete expansion anchors (CEAs) are commonly used to secure equipment to concrete floors. However, anchor bolts may loosen over time during plant operation due to equipment vibration and other factors, resulting in installation torque levels lower than those initially applied. Because the anchorage condition affects the boundary conditions that influence the dynamic characteristics of the equipment, the performance of CEAs used for securing important equipment should be evaluated. CEAs should be tightened to the installation torque recommended by the manufacturer, but in practice, they are often installed with torque values that differ from the standard. Therefore, it is necessary to evaluate the performance of CEAs subjected to over-torque or under-torque conditions compared with the manufacturer’s recommendations. In this study, tensile tests were conducted on M12 CEAs installed with various torque levels under the same conditions. The anchors were installed in uncracked, low-strength concrete blocks fabricated in accordance with ASTM standards and tested following the procedures specified in ACI 355.2. The failure modes of the CEAs were examined, and the concrete breakout strength was evaluated through tensile testing. Based on the experimental results, the effects of installation torque on the tensile performance of CEAs were analyzed and discussed, and the results were compared with the anchor strength equations provided in the current design standard. |