15 m 실규모 프리스트레스트 콘크리트 보에서 2,400 MPa 강연선의 전달길이 평가 = Transfer Length of 2,400 MPa PS Strand in 15 m-long Full-Scale Pretensioned Prestressed Concrete Beam

다국어 초록 (Multilingual Abstract)

In this study, 14.8 m long full scale pretensioned prestressed beam using 2,400 MPa PS strand was fabricated and the transfer length of the strand was investigated by measuring strains on nearby reinforcement steel bars. The test results of the beam were compared with small size specimen tests with a strand from previous researches (Oh and Kim, 2000; Yim et al., 2015). The full scale test showed smaller transfer length and smaller difference in the transfer lengths between at cut (sudden release by flame cut) and dead ends than small specimens with a strand. Evaluation on the equation of transfer length proposed by Oh et al. (2014), based on test and analysis results of transfer length of 1,860 MPa strand considering concrete compressive strength and concrete cover depth, was used to calculate the transfer length of 2,400 MPa PS strand in full scale beam as well as small specimens with a strand. Comparison of the evaluation and test results presented that the equation overestimates the transfer length of 5~9% in small specimen tests, however, more than 30% in full scale beam specimen for 2,400 MPa PS strand.

국문 초록 (Abstract)

본 연구에서는 2,400 MPa PS강연선을 이용하여 14.8 m 프리텐션 보를 제작하였으며, 프리텐션 긴장력 도입 시 인접 철근에서의 변형율를 계측하여 전달길이를 평가하였다. 기존의 단위 강연선의 전달길이 평가를 위한 작은 단면 시편 실험결과(Oh and Kim, 2000;Yim et al., 2015) 보다는 전달길이가 작게 나타났으며, 절단(가스 절단) 단부와 고정 단부의 전달길이 차이가 상대적으로 더 작은 것으로 평가되었다. 1,860 MPa PS 강연선을 기반으로 콘크리트 피복두께와 강도까지 고려하여 유도된 전달길이 산정식을(Oh et al., 2014) 2,400 MPa PS 강연선 적용 소형 시편 실험체와 보 부재 실험체에 적용하여 전달길이를 산출하였다. 계산 및 실험결과 비교를 통해, 1,860 MPa PS 강연선을 기반으로 유도된 전달길이 산정식은 2,400 MPa PS 강연선 소형 시편 실험체의 경우 약 5~9%, 보 부재 실험체의 경우 30% 이상 전달길이를 과대평가하고 있는 것으로 평가되었다.

참고문헌 (Reference)

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2 KCI, "Structural Concrete Design Code"

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9 CEN, "EN 1992-1-2 Eurocode 2: Design of Concrete Structures. Part 1-2: General Rules—Structural fire Design Comité Européen de Normalisation"

10 ACI Committee, "Building Code Requirements for Structural Concrete (ACI 318-08) and Commentary"

11 Oh, B. H., "Analysis and Prediction of Transfer Length in Pretensioned, Prestressed Concrete Members" 111 (111): 549-560, 2014

12 임홍재, "2,400 MPa PS 강연선을 이용한 프리텐션 부재의 전달길이에 대한 실험적 연구" 한국방재학회 15 (15): 41-49, 2015