• Journal of Korean Society of Coastal and Ocean Engineers
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• v.16 no.3
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• pp.142-151
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• 2004

A method for the determination of concrete armor unit weights with hydraulic stability and structural stability may be formulated in this paper. The hydraulic stability is analyzed by using Hudson's formula, the structural stability is also studied by evaluation of maximum flexural tensile stresses in armor unit induced by the impact loads and by comparison of those with the tensile resistance strength directly. The applicable criteria for concrete armor units can be represented as a function of design wave heights with return period, armor weights, and tensile strengths for the practical uses. In addition, reliability analyses for two failure modes are carried out to take into account some uncertainties. Finally, a series system for two-failure mode analysis can be made up straightforwardly, by which the optimal weights of armor units can be estimated with the various relative breakages, given the specific target probability of failure under the concepts of reliability-based design method.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.33 no.6
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• pp.357-366
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• 2021

In this study, hydraulic model tests were performed to investigate the stability of armor units at harbor side slope for rubble mound structures. The Korean design standard for harbor and fishery port suggested the design figures that showed the ratio of the armor weight for each location of rubble mound structures and it could be known that the same weight ratio was needed to the sea side and harbor side (within 0.5H from the minimum design water level) slope of rubble mound structures. The super structures were commonly applied to the design process of rubble mound structures in Korea and the investigation of the effects of super structures would be needed. The stability number (N_od = 0.5) was applied (van der Meer, 1999) and it showed that the armor (tetrapod) weight ratio for harbor side slope of rubble mound structures needed 0.8 times of that for sea side slope.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.35 no.5
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• pp.102-108
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• 2023

In this study, hydraulic model tests were performed to investigate the stability of armor units at harbor side slope for rubble mound structures. The armor units on the rear slope were rocks. The Korean design standard for harbor and fishery port suggested the design figures that showed the ratio of the armor weight for each location of rubble mound structures and it could be known that the same weight ratio was needed to the sea side and rear side slope of rubble mound structures. The crest elements were commonly applied to the design process of rubble mound structures in Korea and the investigation of the effects of super structures would be needed. The damage rate (S =2) was applied and the stable wave height was measured for each test condition. The results were suggested as the armor weight ratio of the rear side slope(armor rock) to the sea side slope (tetrapod) in relation to the relative crest height.

• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.303-303
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• 2020

국내의 주요 외곽시설은 대수심화 및 설계외력의 증대 등으로 경제성 및 안정성 등의 확보를 위해 혼성제 형식의 구조물을 적용하는 사례가 주를 이루고 있다. 혼성제 근고부 안정성과 관련해서는, 설계파에 대한 안정적인 피복재 중량을 구하는 것이 설계상 중요하다. 기존의 직각 입사파에 대한 연구는 많이 수행되어 왔으나, 경사 입사파 조건에 대한 검토 사례는 미미한 실정이다. 또한 직각입사 뿐만 아니라 경사 입사파에 대한 근고부 중량산정식으로 확장된 Tanimoto식을 적용하고 있으나, 수리실험과 중량산정식에 대한 오차가 발생하고 있어 수리실험을 통해 기존의 산정식에 대한 검토가 필요하다. 따라서 본 연구에서는 경사입사파 조건에 따른 혼성제 제두부 구간의 피복재 안정성에 대하여 실험을 수행하였다. 설치수심은 0.3m 수심으로 고정하고, 입사각도를 0°, 30°, 45°, 60° 및 75°로 변화시켜 실험을 수행하였다. 전체 연장 10m의 모형에서 종점부 1m 구간을 실험구간으로 설정하고, 피복재의 종류는 피복석(50g), 콘크리트 피복블록(Tetrapod, Tripod)를 사용하였으며, 파랑조건은 불규칙파를 적용하였다. 주기 및 파고를 변화시켜 수리실험을 수행하였다. 실험결과는 제두부 구간에 피복된 피복재의 구간별 피해율을 분석하기 위해 구역분할도 적용하였으며, 확장된 Tanimoto식과 비교분석하여 중량산정식의 타당성을 검토하였다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.39 no.6
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• pp.769-777
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• 2019

Low crested coastal structures such as detached breakwaters and submerged breakwaters (artificial reefs) have been commonly used as coastal protection measures. The armour units of these structures are unstable than those in non-overtopped structure cases. The stability of low crested structures armoured by rock has been suggested in existing studies. In this study, the stability of Tetrapods armour units on theses structures has been investigated using two-dimensional hydraulic model tests. The effect of wave steepness and freeboard on the armour stability on crest, front, and the rear slope has been investigated. Armour units were mostly damaged near the upper part of the seaward slope and the crest of the seaward side. From the experimental data, the new empirical formula for the stability coefficients of the Tetrapods was proposed.

• 한국방재학회:학술대회논문집
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• 2009.02b
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• pp.125.2-125.2
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• 2009

• Proceedings of the Korea Water Resources Association Conference
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• 2012.05a
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• pp.716-716
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• 2012

최근 항만구조물을 설계함에 있어 대수심 및 고파랑 지역에 설치되는 외곽시설의 상당수는 직립식 케이슨 혼성제 단면을 채택하고 있다. 이는 상대적으로 수심이 깊고, 설계파와 같은 외력 조건이 크기 때문에 경사제에 비하여 경제성 및 시공성이 유리하기 때문으로 판단된다. 그렇지만 아직까지 소규모 항만 및 어항시설에 있어 경사제를 채택하고 있다. 본 연구에서는 이와 같은 경사식 구조물을 설계함에 있어 월파에 의한 방파제 배후 경사면에 피복된 피복재의 안정성을 검토하며, 실험사례를 통하여 최적 설계안 및 설계방향을 제시하고자 한다. 경사식 구조물 배후 사면 피복재의 안정 중량에 대해서는 우리나라의 항만 구조물의 설계기준(항만 및 어항설계기준, 2005) 뿐만 아니라 국외의 설계기준(CEM, Coastal engineering manual, 2005 등)에서도 아직까지 설계법을 제시하고 있지 않고 있다. 본 연구에서 수행한 단면 수리모형실험에서는 1/50의 실험축척을 적용하여 대상 외곽 구조물에 대하여 수리특성과 안정성을 검토하였다. 특히 경사제 배후의 안정성 확보를 위하려 동일 구간에 대하여 설계파 조건 등을 중심으로 총 9개의 실험안을 설정하여 안정성을 검토하였다. 아래 그림은 이중 초기 설계안과 최종적으로 제안된 제시안에 대한 완성모형, 실험장면 및 결과이다. 일반적으로 접안시설과 외곽시설이 어느 정도 이격되어 있어 적정량의 월파를 허용할 수 있는 경우 상치콘크리트의 형상 및 마루높이을 변경하여 월파의 낙하 및 도달거리를 배후면의 안정성을 확보할 수 있을 정도로 유도함으로써 안정적인 구조물 설계가 가능할 것으로 판단된다.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.15 no.4
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• pp.249-258
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• 2003

In this study, the stability of armor blocks of rubble-mound breakwaters is investigated based on the 2-dimensional hydraulic model test with irregular waves. Amor blocks were used the three types; rock, cube and tetrapod. And Hudson formula and van der Meer formula which are used for calculating the weight of armor blocks are considered. Hudson formula was developed from regular wave tests, while van der Meer formula was developed from irregular wave tests. The purpose of this paper is to compare and test two selected stability formulas using the experimental data.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.20 no.1
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• pp.42-48
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• 2008

A system of risk assessment is developed by using the reliability analysis which evaluate quantitatively both stability and performance of sloped-coastal structures according to several scenarios of sea-level rise. By using reliability functions on armor unit and run-up, the probabilities of failure can be straightforwardly calculated with respect to several design parameters such as nominal diameter of armor unit, slope of coastal structure, and freeboard height. By comparing the results before and after sea-level rise, it may be possible to exactly assess some ranges of decrease of stability and performance of sloped-coastal structure with respect to sea-level rise. Therefore, it can also be possible to make a decision which parameters should be repaired or strengthened in order to maintain the original stability and performance of sloped-coastal structures. Finally, The present results may be useful for designing some kinds of new sloped-coastal structures including the effect of sea-level rise.

• Proceedings of the Korea Water Resources Association Conference
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• 2001.05b
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• pp.1139-1144
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• 2001