비부착 강연선에 대한 포스트텐션 정착구 개발 및 성능 시험 Development and Performance Test for Unbonded Post-Tensioned Anchor 조 아 서* Cho, Ah Sir 조 영 욱** Jo, Yeong Wook 전 병 갑*** 강 현 구**** Jeon, Byong Kap Kang, Thomas H.-K. ABSTRACT An unbonded post-tensioned anchor for a 15.2 mm diameter 7-wire strand was developed based on finite element analyses. To evaluate its performance, static load tests and load transfer tests were conducted following KCI-PS101. 요 약 이 연구에서는 유한요소해석을 통해 직경 15.2mm 비부착 강연선을 사용하는 단일 포스트텐션 정착 구를 개발하였으며, 콘크리트 표준시방서에 따라 KCI-PS101에 제시된 정하중시험과 하중전달시험을 통해 그 성능을 시험하였다. 1. Introduction Currently Korean markets for unbonded post-tensioned (PT) anchors fully depend on imports from European countries or the U.S. However, because the price of the imported anchors and their accessories is quite expensive, the use of PT systems is not preferred by Korean practicing industry. In this study, given the overpriced PT anchor in Korean construction market, a post-tensioned anchor for an unbonded single strand is attempted to be developed through finite element analyses, and its structural performance is experimentally verified. 2. Anchor Development based on Finite Element Analysis As GCD 500-7 is a typical material used for PT anchors, it is assumed to yield at 400 N/mm2 and have an elastic modulus of 200,000 MPa. Parametric analysis is performed for each variable, during which the maximum von Mises values are monitored. From the analysis, final design is determined considering both optimization and practicality, as shown in Fig. 1. * ** *** **** 정회원, 정회원, 정회원, 정회원, 서울대학교 건축학과 석사과정 삼성물산주식회사 건설부문 주택ENG팀 차장 삼성물산주식회사 건설부문 주택ENG팀 부장 서울대학교 건축학과 교수 한국콘크리트학회 2014 봄 학술대회 논문집 Fig. 1 3D model and test product of developed anchor Fig. 2 Details of static load test specimen Fig. 3 Details and test set-up of load (All units: mm) transfer test specimen (All units: mm) 3. Methods Static load tests and load transfer tests are conducted following KCI-PS101.1) The static load test is to verify the performance of anchorage system, while the load transfer test is to determine reinforcing details ahead of the PT anchor and confirm the interaction between the PT anchor and reinforcement. Details of specimens are shown in Figs. 2 and 3. 4. Conclusions Based on the analysis and test results, it is found that the developed anchor has a capacity exceeding the nominal tensile strength of the strand and that a PT force of up to 1.6 times the nominal strength is transferred from the anchor to the un-reinforced anchorage zone with no evidence of deterioration or damage. As such, the interaction between the developed anchor and reinforcement is adequate so that no additional reinforcing bars are necessary to reinforce the anchorage zone. Acknowledgement Supports provided by Samsung C&T, NRF of Korea (No. 2012-005905), and Smart Civil Infrastructure Research Program (13SCIPA02) of MOLIT are highly appreciated. Reference 1. Korea Concrete Institute, Standard Specification for Concrete and Commentary, Korea Concrete Institute, 2010, 762pp.