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http://dx.doi.org/10.4334/JKCI.2002.14.4.521

Restraint Coefficient of Long-Term Deformation and loss Rate of Pre-Compression for Concrete  

연정흠 (인하대학교 토목공학과)
주낙친 (인하대학교 토목공학과)
Publication Information
Journal of the Korea Concrete Institute / v.14, no.4, 2002 , pp. 521-529 More about this Journal
Abstract
A restraint coefficient for creep and dry shrinkage deformation of concrete in a composite section was derived to calculate the residual stress, and an equation for the loss rate of the pre-compression force was proposed. The derived restraint coefficient was computed by using the transformed section properties for the age-adjusted effective modulus of elasticity. The long-term behavior of complicate composite sections could be analyzed easily with the restraint coefficient. The articles of the current design code was examined for PSC and steel composite sections. The dry shrinkage strains of $150 ~ 200$\times$10^{-6}$ for the computations of the statically indeterminate force and the expansion joint could be under-estimated for less restrained sections such as the reinforced concrete. The dry shrinkage strain of $180$\times$10^{-6}$ for the computation of residual stress in the steel composite section was unreasonably less value. The loss rate of 16.3% of the design code for the PSC composite section in this study was conservative for the long-term deformation of the ACI 205 but could not be used safely for that of the Eurocode 2. For pre-compressed concrete slab in the steel composite section, the loss rate of prestressed force with low strength reinforcement was much larger than that with high strength tendon. The loss rate of concrete pre-compression increased, while that of pre-tension decreased due to the restraint of the steel girder.
Keywords
concrete; long-term deformation; creep; dry shrinkage; composite section; restraint coefficient; loss rate;
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  • Reference
1 Bazant, Z. P., "Prediction of Concrete Creep Effects Using Age-Adjusted Effective Modulus Method," ACI Structural Journal, Vol. 63, 1972, pp.212-217.
2 한국콘크리트협회, "건설교통부 제정 콘크리트구조 설계기준," 기문당, 1999.
3 대한토목학회, 건설교통부 제정 도로교 표준시방서, 기문당, 1996.
4 ACI Committee 209, "Prediction of Creep, Shrinkaga, and Temperature Effect in Concrete Structures," ACI 209R-92, American Concrete Institute, 1997.
5 AASHTO, "Standard Specifications for Highway Bridges," 6th Edition, American Association of Highway and Transportation Officials, 1996.
6 CEN (European Committee for Standardization), Eurocode 2: Design of Concrete Structures, ENV (European Prestandard) 1992-1-1, Brussels, Belgium, 1994.
7 장승필, 심창수, 최규용, 정철헌, "프리캐스트 교량 바닥판의 종방향 프리스트레스 손실량," 대한토목학회 논문집, 제19권, I-6호, 1999, pp.917-927.   과학기술학회마을
8 Gilbert, R. I., "Time Effects in Concrete Structures," Elsevier, Amsterdam, 1988.
9 구민세, 박영제, 정봉수, "하중재하를 이용한 연속 프리플렉스 합성보의 라멘구조에의 적용," 대한토목학회 학술발표회 논문집, 2000, pp.661-664.
10 한만엽, 김진근, 이차돈, 박준범, "프리스트레스를 단계적으로 도입하는 IPC 거더의 설계 이론 연구," 한국콘크리트학회 논문집, 제12권, 4호, 2000, pp.121-130.   과학기술학회마을
11 건설교통부, 도로설계편람 III, 한국건설기술연구원, 2001.
12 한국도로교통협회, "건설교통부 제정 도로교 설계기준," 도서출판 건설정보, 2000.