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Title |
Evaluation of Prestress Loss in Prestressing Reinforcing Units using Steel Bar and Pipe
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Authors |
심재일(Jae-Il Sim) ; 문주현(Ju-Hyun Mun) |
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DOI |
https://doi.org/10.11112/jksmi.2021.25.4.75 |
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Keywords |
프리스트레스트의 응력손실; 릴랙세이션; 프리스트레싱; 보강재; 압축 및 인장응력 Loss of prestressing stress; Relaxation; Prestressing; Reinforcing steel bar; Compressive and tensile stress |
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Abstract |
The objective of this study is to examine the loss of prestressing stress in the developed prestressing reinforcing units using steel bar andpipe (SP). The main parameters were the reinforcing bar type, the magnitude of prestressed force, and prestressing method. The test results showedthat the loss of prestressing stress for SP was highest in the initial prestressing step, which was higher for the compression introduction typed specimensthan tension introduction typed specimens. The loss of prestressing stress of SP made with P800 was 1.6% for the compression introduction typedspecimen with 0.8??, which was lowest than the other specimens. Meanwhile, the relaxation of SP with the respect to the time ranged between 0.4and 1.9%, irrespective of SP material type, the magnitude of prestressed force, and prestressing method. These values were less than 2.5%, which isthe maximum value for the relaxation of prestressed reinforcing steel bars in design codes. Consequently, considering the loss of stress developed inthe initial prestressing step, the developed SP material type, prestressing introduction method, and magnitude are recommended to be P800,compression introduction type, and 0.8??
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