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Effects of Bar Deformation Height on Bond Degradation Subject to Cyclic loading
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 Title & Authors
Effects of Bar Deformation Height on Bond Degradation Subject to Cyclic loading
Lee, Jae-Yuel; Kim, Byong-Kook; Hong, Gi-Suop; Choi, Oan-Chul;
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One of the reasons for brittle failure in reinforced concrete structures subjected to severe earthquake is due to large local bond-slippage of bars resulting in fast bond degradation between reinforcing bars and concrete. This study aims to evaluate effects of bar deformation height on bond performance, specially, bond degradation under cyclic loading. Bond test specimens were constructed with machined bars with high relative rib areas. The degree of confinement by transverse bars is also another key parameters in this bond test. From test results, amounts of energy dissipation are calculated and compared for each parameter. Test results show that bond strength and stiffness drops significantly as cycles increases. The confinement and high relative rib area are effective to delay bond degradation, as the reduction of bond strength of cyclic loading compared to monotonic loading decreased for bars with large confinement and high relative rib areas. The energy dissipation also increases as the degree of confinement and relative rib area increases. However, tested bars with very high rib areas show that the bond may be damaged at relatively small slip because of high stiffness. The study will help to understand the bond degradation mechanism due to bar deformation height under cyclic loading and be useful to develop new deformed bars with high relative rib areas.
bond degradation;confinement;cyclic load;deformation height;energy dissipation index;
 Cited by
높은 마디면적 고강도 철근의 부착강도에 관한 실험적 연구,홍건호;최동욱;최완철;홍기섭;

한국콘크리트학회논문집, 2005. vol.17. 3, pp.375-384 crossref(new window)
반복하중하의 부착응력-슬립 관계에 미치는 철근 부식의 영향,김철민;박종범;장승필;김지상;

한국콘크리트학회논문집, 2010. vol.22. 2, pp.179-186 crossref(new window)
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