• Proceedings of the Korea Institute of Fire Science and Engineering Conference
• /
• 2013.04a
• /
• pp.4-5
• /
• 2013

프리스트레스트된 프리캐스트 콘크리트 부재는 장경간이 가능하고 공장생산으로 품질관리가 용이하다. 그러나 프리스트레싱 텐던이 화재에 노출되는 경우 일반 철근에 비해 급격하게 강도를 상실해 구조물의 붕괴로 이어질 수 있다. 국내의 경우 실험에 기초한 내화성능에 대한 연구는 활발히 이루어지고 있으나 그에 반해 성능기반 설계법이 활성화 될 때 요구되는 수치해석적인 연구는 많이 부족한 실정이다. 따라서 본 연구에서는 문헌조사를 통해 이전에 수행된 실험 데이터를 통해 현재 외국에서 활발히 사용되는 수치해석 프로그램을 검증하고 수치해석 모델링을 통해 각각의 내화시간에 따른 적절한 피복 두께를 제안하였다.

• Magazine of the Korea Concrete Institute
• /
• v.16 no.4 s.81
• /
• pp.23-33
• /
• 2004

• Magazine of the Korea Concrete Institute
• /
• v.19 no.4
• /
• pp.45-50
• /
• 2007

• Magazine of the Korea Concrete Institute
• /
• v.11 no.5
• /
• pp.59-65
• /
• 1999

• Magazine of the Korea Concrete Institute
• /
• v.10 no.5
• /
• pp.42-46
• /
• 1998

• Magazine of the Korea Concrete Institute
• /
• v.16 no.1 s.78
• /
• pp.12-21
• /
• 2004

• Magazine of the Korea Concrete Institute
• /
• v.16 no.1 s.78
• /
• pp.33-38
• /
• 2004

• Magazine of the Korea Concrete Institute
• /
• v.16 no.1 s.78
• /
• pp.39-48
• /
• 2004

• Journal of the Korea Concrete Institute
• /
• v.23 no.3
• /
• pp.353-364
• /
• 2011

In a previous research performed by the authors, the allowable compressive stress coefficient (K) in pretensioned members with rectangular section at transfer was proposed based on strength design theory. In this study, a subsequent research of an enormous analysis was performed to determine the K factor for Tee and inverted Tee section members, considering the effect of section height (h), section type, amount of tendons ($A_{ps}$), and eccentricity ratio (e/h). Based on the analysis results, the allowable compressive stress coefficients (K) for Tee and inverted Tee section members at transfer were derived, which limit the maximum allowable stresses as 80% and 70% of the compressive strengths at the time of release for Tee section and inverted Tee section, respectively. And these were larger than the allowable stresses specified in domestic and other international codes. In order to verify the proposed equations, they were compared to the test results available in literature and other codes, which showed that the allowable stresses in domestic and international codes are unconservative for the cases with low eccentricity ratios while conservative for those with high eccentricity ratios. The proposed equations, however, estimate the allowable stresses of the Tee and inverted Tee section members reasonably close to test results.

• Journal of the Korea Concrete Institute
• /
• v.13 no.1
• /
• pp.16-22
• /
• 2001

Pretensioned spun high strength concrete (PHC) pile has to be quality-controlled and provided an adequate concrete cover to assure high load carrying capacity, impact resistance, economy, and durability. During spun pre-casting, the pile section is divided into several segregated layers such as laitance, paste, mortar, and concrete layers. Greater the thickness of segregated layers, more difficult it is to guarantee the capacity and the durability of PHC pile. The experimental study was performed to investigate the effects of centrifugal condition on the segregated layers of materials and the compressive strength of concrete for PHC pile. The considering factors in the test were centrifugal time and magnitude of centrifugal force. These factors have been found to have greater influence on the segregation than the concrete strength. The moderate centrifugal condition has to be considered to maintain quality assurance in the production of PHC pile, especially to provide the adequate concrete cover over its tendons.