• Title/Summary/Keyword: Marine concrete bridges

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Air-borne Chloride Content of Highway Bridges Exposed to Marine Environment (해양환경에 위치한 국내 고속도로 교량의 비래염분량 측정 결과)

  • 정해문;유환구;류종현;안태송;김수만;오병환
    • Proceedings of the Korea Concrete Institute Conference
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    • 2002.05a
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    • pp.743-748
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    • 2002
  • Chloride ingress into concrete followed by reinforcement corrosion and deterioration of concrete structures is a major problem for many structures under chloride attacks. Large-scale concrete structures directly exposed to seawater such as SeoHae Grand Bridge are increasingly constructed along the coast in Korea. It is necessary to investigate the environmental conditions of concrete structures exposed to chloride attacks. In this study, the air-borne chloride contents of highway bridges exposed to marine environment in Korea were measured.

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The Estimation of Surface Chloride Content and Durability of the Marine Concrete Bridges in South Coast (남해안 해상 콘크리트 교량의 표면염화물이온농도 및 내구성 평가)

  • Jung, Dae-Jin;Choi, Ik-Chang
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.20 no.6
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    • pp.730-737
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    • 2014
  • In this study, chloride content of marine concrete bridge at the south coast in 5~34years was calculated based on the measured data and the validity of the proposed value was evaluated. Also, correlation of existence of salt injury prevention coating, chloride content, carbonation depth and the compressive strength of marine concrete bridges were derived and relationship of the four was evaluated. According to the research results, surface chloride content value in the tidal zone proposed form KCI 2009 and value in the splash zone and atmospheric zone proposed form Cheong et al.(2005) was the most valid. Also, salt injury prevention coating of marine concrete bridges had the outstanding effect of preventing chloride content penetration, carbonation depth and reduction in the compressive strength. Compressive strength of concrete was reduced by the increase of carbonation depth and chloride content.

Impact of multiple component deterioration and exposure conditions on seismic vulnerability of concrete bridges

  • Ghosh, Jayadipta;Padgett, Jamie E.
    • Earthquakes and Structures
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    • v.3 no.5
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    • pp.649-673
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    • 2012
  • Recent studies have highlighted the importance of accounting for aging and deterioration of bridges when estimating their seismic vulnerability. Effects of structural degradation of multiple bridge components, variations in bridge geometry, and comparison of different environmental exposure conditions have traditionally been ignored in the development of seismic fragility curves for aging concrete highway bridges. This study focuses on the degradation of multiple bridge components of a geometrically varying bridge class, as opposed to a single bridge sample, to arrive at time-dependent seismic bridge fragility curves. The effects of different exposure conditions are also explored to assess the impact of severity of the environment on bridge seismic vulnerability. The proposed methodology is demonstrated on a representative class of aging multi-span reinforced concrete girder bridges typical of the Central and Southeastern United States. The results reveal the importance of considering multiple deterioration mechanisms, including the significance of degrading elastomeric bearings along with the corroding reinforced concrete columns, in fragility modeling of aging bridge classes. Additionally, assessment of the relative severity of exposure to marine atmospheric, marine sea-splash and deicing salts, and shows 5%, 9% and 44% reduction, respectively, in the median value bridge fragility for the complete damage state relative to the as-built pristine structure.

The Assessment of Chliride Attack of Concrete Structure in Marine Environment (해양환경하에 있는 콘크리트 구조물의 염해에 대한 고찰)

  • 문한영;김성수;류재석;김성섭
    • Proceedings of the Korea Concrete Institute Conference
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    • 1996.04a
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    • pp.83-88
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    • 1996
  • Reinforced-concrete structures built on the seashore or in seawater are damaged from flying-salt of chloride ion in the seawater. Recently many bridges are being constructed under marine enviornment and there are many serious problems of chlofide attack owing to penetration of chloride ion. And up to now it has not only so little a seatch about damage from flying-salt and seawater but also little systematic study outcome about steel corrosion. In this study we investigate the concrete deterioration and steel corrosion of RC bridges on the seashore. Environmental conditions are investigated, and compressive strength, carbonation depth and steel-corrosion degree are measured.

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A Study on the Evaluation of the Environmental Performance of Salt Damage in Concrete Bridges under Marine Environment (해양 환경하 콘크리트 교량의 염해환경 성능평가 연구)

  • Chai, Won-Kyu;Lee, Myeong-Gu;Son, Young-Hyun;Hong, Sung-Wook
    • Journal of the Korean Society of Safety
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    • v.33 no.5
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    • pp.60-69
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    • 2018
  • This study aims to investigate in the assessment of salt damage conditions in concrete structures under marine environment conditions. It aims also to improve the durability of new concrete bridge through applying the life prediction method of salt damaged bridges. As measuring chloride contents of these bridges on the southwest coastal area, it is shown that the average amount of chloride on these surfaces close to shore is $10.5kg/m^3$. This figure is much higher than that of the Standard Specification for Concrete($1.5kg/m^3{\sim}2.5kg/m^3$). In contrast, it is shown the average amount of chloride on these surfaces in tide zone is $13.1kg/m^3$. Its figure is much lower than that of the Standard Specification for Concrete($20kg/m^3$). And the life of bridges is estimated about 17 years. To improve the durability for salt damage, these bridges are applied to surface treatment method which the replacement rate of furnace slag is 60%. Under this condition, it is expected to be 110 years. Consequently, it is clear that the use of slag replacement rate, surface treatment agent, and anti-corrosion agent to control chloride penetration effects of a submerge-based concrete bridge will be required.

Rapid Corrosion Test on Marine Reinforcing Steel (부식촉진에 의한 해양.항만 철근 콘크리트 구조물의 철근 방식에 관한 실험적 연구)

  • 정근성;문홍식;송호진;이상국;정영수
    • Proceedings of the Korea Concrete Institute Conference
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    • 2001.11a
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    • pp.537-542
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    • 2001
  • Recently long-span bridges, such as Kwang-Ahn Grand bridge, Seo-Hae Grand Bridge, Young-Jong Grand Bridge, etc, have been designed and constructed near the shore. It needs to maintain the durability of marine concrete structures which are exposed to severe chloride environments. It is well known that corrosion of reinforcement steels in concrete structure is the most important cause for the durability of concrete structure which can be controlled by systematic preparatory corrosion protection works for economic and safe infrastructures. Various corrosion protection systems have been used for the corrosion protection of reinforcement steels from detrimental chemical components such as chloride, sulphate and etc. Since chloride can be penetrated into concrete in a variety way, an effective method has to be adopted by taking into full economical aspects and technical data of each protection system. The objective of this experimental study is to investigate the corrosion behavior of reinforcing steel in laboratory concrete specimens which are exposed to cyclic wet and dry saltwater, and then to develop pertinent corrosion protection system, such as corrosion inhibitors and cathodic protection for reinforced concrete bridges exposed to chloride environment. Resistance of various corrosion inhibitors and impressed current system have been experimentally evaluated under severe environmental conditions, and thus effective corrosion protection systems could have been Practically developed for future concrete construction.

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Cathodic Protection Characteristics and Effective Length of Protection Current of Concrete Pile using Zn-mesh Sacrificial Anode (아연 메쉬 희생양극을 이용한 콘크리트 파일의 음극방식 특성 및 방식전류 유효거리)

  • Kim, Ki-Joon;Jeong, Jin-A;Lee, Woo-Cheol
    • Proceedings of the Korea Concrete Institute Conference
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    • 2008.11a
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    • pp.773-776
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    • 2008
  • The corrosion of steel in concrete is significant in marine environment. Marine bridges are readily deteriorated due to the exposure to marine environment. Salt damage is one of the most detrimental causes to concrete bridges and port structures. Especially, the splash and tidal zones around water line are comparatively important in terms of safety and life-time point of view. During the last several decades, cathodic protection (cp) has been commonly accepted as an effective technique for corrosion control in concrete structures. Zn-mesh sacrificial anode has been recently developed and started to apply to the bridge column cp in marine condition. The detailed parameters regarding Zn-mesh cp technique, however, have not well understood. This study is to investigate how much Zn-mesh cp influences along the concrete column at elevated temperature. About 100cm column specimens with eight of 10cm segment rebars have been used to measure the variation of cp potential with the distance from Zn-mesh anode at both 10$^{\circ}$C and 40$^{\circ}$C in natural seawater. The cp potential change and current diminishment along the column specimens have been discussed for the optimum design of cp by Zn-mesh sacrificial anode

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Cathodic Protection of Reinforced Concrete Slab with Zn-Mesh in Marine Environment (해양환경 중 Zn-mesh를 적용한 콘크리트 슬랩의 음극방식 특성)

  • Kim, Ki-Joon;Jeong, Jin-A;Lee, Woo-Chul
    • Proceedings of the Korea Concrete Institute Conference
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    • 2008.04a
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    • pp.1065-1068
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    • 2008
  • Marine bridges are readily deteriorated due to the exposure to marine environment. The concrete deterioration occurred by corrosion of steel in concrete is mainly relevant to chloride in seawater. Chloride ions penetrate through porous concrete, and then reach to the reinforcing steel, and finally corroded them. The corrosion by-products(rusts) increase the volume as much as 6 to 10 times of origin steel. this creates expanding pressure and tensile stress, which cause the structures cracking and spalling. Sometimes the rebar corrosion is accelerated, and then collapsed catastrophically. In order to prevent corrosion damage, it is important to understand well regarding the reason of concrete corrosion, the quantification of its damage, and protection method/system to stop or to mitigate the corrosion. In this study, slab specimens were fabricated to evaluate the effect of cathodic protection which was simulated to marine bridges, and/or port structures. Zn-mesh sacrificial anode has been applied as a chathodic protection system and accelerated test conditions, i.e. temperature and salt concentration have been used in this study.

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Research for Corrosion Protection System of Embedded steels for Reinforced Condrete Exposed to Chloride Environments. (염해환경하 콘크리트의 철근방식공법 연구)

  • 문홍식;류금성;정영수;박희상
    • Proceedings of the Korea Concrete Institute Conference
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    • 1999.10a
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    • pp.281-284
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    • 1999
  • Bridge structure is known as one of important infrafacilities for comfortable human life. Recent long-span bridges, such as Kwang-Ahn Grand bridge, S대-Hae Grand Bridge, Young-Jong Grand Bridge, etc, have been designed and constructed near the seaside without in-depth consideration of concrete durability problems, It is in particular noted that corrosion of reinforcement steel in concrete is very important for the durability enhancement of concrete structures. The objective of this experimental study is to investigate the corrosion degree of reinforcing steels in concrete specimens which are exposed to cyclic wet and dry saltwaters, and then to develop pertinent corrosion protection system such as rational cover depth, corrosion inhibitors, cathodic system for reinforced concrete bridges exposed to marine environment.

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Corrosion Protection System and Measurement for Reinforcing Steels in Concrete (철근부식도 측정 및 방식기법 제시)

  • 문홍식;이상국;류금성;정영수
    • Proceedings of the Korea Concrete Institute Conference
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    • 2000.04a
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    • pp.827-832
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    • 2000
  • Bridge structure is known as one of important infrafacilities for comfortable human life. Recent long-span bridges, such as Kwang-Ahn Grand bridge, Seo-hae Grand Bridge, Young-Jong Grand Bridge, etc, have been designed and constructed near the seaside without in-depth consideration of concrete durability problem. It is in particular noted tat corrosion of reinforcement steel in concrete is very important for the durability enhancement of concrete structures. The objective of this experimental study is to investigate the corrosion behavior of reinforcing steels in concrete specimens which are exposed to cyclic wet and dry saltwaters, and then to develop pertinent corrosion protection system such as rational cover depth, corrosion inhibitors, cathodic system for reinforced bridges exposed to marine environment.

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