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Title |
Reliability Evaluation of Stainless Steel Post-Installed Expansion Anchor for Seismic Design Installed in Cracked Concrete
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Authors |
김문길(Mun-Gil Kim) ; 심혜정(Hye-Jung Sim) ; 천성철(Sung-Chul Chun) ; 안영승(Yeong-Seung An) |
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DOI |
https://doi.org/10.4334/JKCI.2023.35.4.433 |
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Keywords |
균열 콘크리트; 후설치 앵커; 스테인리스스틸; 신뢰성 시험; 앵커범주 cracked concrete; post-installed anchor; stainless steel; reliability tests; anchor category |
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Abstract |
Three types of reliability tests, as per evaluation guidelines, were conducted on stainless steel post-installed expansion anchors developed to enhance durability and earthquake resistance. The purpose of these tests was to evaluate sensitivity to “installation effort reduction,” “crack width and large hole diameter,” and “crack width and small hole diameter,” respectively. Instead of using the existing splitting wedge, cracks were formed using a new method involving two hydraulic rams located on both sides of the anchor hole to create a state of cracked concrete. The test conditions for each test were kept consistent by precisely forming the target crack width using a PI-gauge, and the formation of cracks throughout the entire depth of the anchor hole was confirmed using an endoscopy camera. The test results indicated that all 39 anchors failed due to pullout failure rather than concrete breakout failure. This was attributed to the anchor sleeve not expanding precisely due to low installation torque or non-standard anchor hole diameter, which reduced the friction resistance between the concrete and the expansion sleeve. As the load increased up to the maximum load, vertical displacement of the anchor and crack width increased in all anchors, while the vertical displacement of the concrete around the anchor remained minimal. After reaching the maximum load, the anchor experienced pullout, resulting in an increase in crack width without an increase in load. Among the six series of tested anchors, five series were evaluated as Anchor Category 1. The improved anchor design aimed at enhancing earthquake resistance in cracked concrete ensured that the anchors exhibited safe and effective behavior under adverse conditions.
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