• Journal of Ocean Engineering and Technology
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• v.15 no.3
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• pp.114-119
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• 2001

Goda formula (Goda, 1973) has been used in the determination of wave pressures acting on a large size caisson such as the pier of the cable stayed bridge at sea. Goda formula, however, is to evaluate the wave pressures acting the infinite vertical caisson of composite breakwater so that it can`t be applied to a large caisson with finite width and length because of diffraction effects. In the present study, three dimensional nonlinear frequence domain method based on perturbation method and boundary integral method is applied to the computation of the linear and nonlinear wave pressures acting on the front of a large size caisson under the variation of its width and length, and angle of incident wave. The numerical results are compared to Goda\`s ones, and then the characteristics of wave pressure distributions acting on a large size caisson are discussed.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.35 no.1
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• pp.119-128
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• 2015

This study investigates the wave pressure characteristics of the pile-supported breakwater with single or double perforated walls through 2-D hydraulic experiments and the measured wave pressures are compared to those of wave pressures by Goda's formula. For single chamber, the measured wave pressures in the front wall and rear wall decreased to about 25% and 30%, respectively, compared to those of wave pressures by Goda's formula. Also, the decrease in the wave pressures for double chamber were about 27%, 53%, and 64% in the front wall, middle wall, and rear wall, respectively. It was found that the pile-supported breakwater with double perforated walls was more efficient than the single chamber due to wave dissipation effects of double slit walls with horizontal slits.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.34 no.3
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• pp.82-92
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• 2022

In recent years, coastal and port structures have attempted to prevent wave-overtopping or provide waterfront areas by installing superstructures on the structural crowns. In general, in the design stage, the Goda formula acting on the front the structure is applied to calculate the wave pressure acting on the superstructure in consideration of the wave-runup of the design wave. However, the wave pressure exceeding the Goda wave pressure could generate depending on the installation location of the superstructure where the wave-overtopping occurs. This study analyzed the applicability of the Goda formula to the wave pressure calculation for the superstructure of the vertical structures through hydraulic model experiments and numerical simulations. Furthermore, this study investigated the magnitude of the wave pressure acting on the superstructure based on detailed numerical results. As a result, the wave pressure acting on the superstructure was up to 120% higher than the maximum wave pressure on the still water surface. In addition, the wave pressure increases exponentially with the Froude number computed by the overtopping water depth at the crown of the structure, and we proposed an empirical formula for predicting the wave pressure based on the Froude number.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.33 no.6
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• pp.321-332
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• 2021

The crown wall with parapet on top of the rubble mound breakwater represents a relatively economic and efficient solution to reduce the wave overtopping discharge. However, the inclusion of parapet leads to increased wave pressure on the crown wall. The wave pressure on the crown wall is investigated by physical model test. To design the crown wall the wave loads should be available, and the horizontal wave pressure is still unclear. Regarding to the horizontal wave pressure on the crown wall, a series of experiments were conducted by changing the rubble mound type structure and the wave conditions. Based on these results, pressure modification factors of Goda's (1974, 2010) formula have been suggested, which can be applicable for the practical design of the crown wall of the rubble-mound breakwater covered by tetrapods.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.2
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• pp.573-584
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• 2013

This study experimentally investigated the change in distribution of wave pressure on the front wall according to the variation of the front wall porosity of the caisson breakwater having the cap of wave chamber. First, the wave pressure for the non-porous caissson corresponding to zero porosity was measured and compared with the pressure formula suggested by Goda(1974). The analysis showed that the measured pressure distribution fairly well agreed with the Goda formula, which confirmed the accurate measurement of wave pressure in the present experiment. In case of the porous caisson, meanwhile, the experiment was performed by varying the front wall porosity as 0.2, 0.25, and 0.3. The wave pressure distribution at the front wall showed little difference according to the porosity for most of the test wave conditions, whereas the pressure slightly increased with the porosity for some test waves whose wave heights and periods were relatively large. However, the difference according to the porsosity was insignificant for the wave force at the front wall.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.42 no.4
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• pp.469-480
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• 2022

To design the crown wall of rubble-mound breakwaters, the horizontal wave load should be available, but determining this load remains difficult. Lee et al. proposed modification factors for Goda's formula for the horizontal wave pressures on acrown wall. The empirical formula by Lee et al. was based on a two-dimensional model test with a relatively narrow armour crest width in front of the crown wall. In this study, a series of experiments at the same facility were conducted on the horizontal wave pressures on the crown wall of a rubble-mound breakwater with a wide armour crest width. As a result, the pressures of the unprotected part of the crown wall were nearly identical to the narrow crest width. However, the pressures of the protected part tended to decrease with a change in the armour crest width. From the experimental results, the horizontal pressure modification factors of Goda's formula including the armour crest width effect are suggested here and are likely applicable to practical designs of the crown walls of rubble-mound breakwaters covered with tetrapods.

• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
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• 1995.10a
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• pp.120-121
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• 1995

In the design of mixed type breakwater, the most important factor to be considered is the wave pressure. In particular, the standing wave pressure has a significant effect on the vertical wall breakwater or mixed type breakwater. Many wave pressure formulas were developed and the Goda's formula［1］ was very frequently used among them by the coastal engineers due to its simplicity and accuracy. (omitted)

• 한국방재학회:학술대회논문집
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• 2010.02a
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• pp.64.1-64.1
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• 2010

국내 지진해일에 관한 연구 중, 구조물에 직접적인 영향을 미치는 파력에 대한 연구가 현재 미미한 실정이다. 본 연구에서는 파고와 입사각, 그리고 유의주기를 기지값으로 하여 파압을 계산하는 Goda(1974)가 제안한 파압공식을 이용하여 파압을 산정하였다. 파고는 Cho(1995) 모델로 산정하였으며 이를 임원항구의 방파제에 적용하였다.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.29 no.6
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• pp.286-304
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• 2017

In this study, we proposed a new-type of circular perforated caisson breakwater consisting of a bundle of latticed blocks that can be applied to a small port such as a fishing port, and numerically investigated the hydraulic characteristics of the breakwater. The numerical method used in this study is OLAFOAM which newly added wave generation module, porous media analysis module and reflected wave control module based on OpenFOAM that is open source CFD software published under the GPL license. To investigate the applicability of OLAFOAM, the variations of wave pressure acting on the three-dimensional slit caisson were compared to the previous experimental results under the regular wave conditions, and then the performance for irregular waves was examined from the reproducibility of the target irregular waves and frequency spectrum analysis. As a result, a series of numerical simulations for the new-type of circular perforated caisson breakwaters, which is similar to slit caisson breakwater, was carried out under the irregular wave actions. The hydraulic characteristics of the breakwater such as wave overtopping, reflection, and wave pressure distribution were carefully investigated respect to the significant wave height and period, the wave chamber width, and the interconnectivity between them. The numerical results revealed that the wave pressure acting on the new-type of circular perforated caisson breakwaters was considerably smaller than the result of the impermeable vertical wall computed by the Goda equation. Also, the reflection of the new-type caisson breakwater was similar to the variation range of the reflection coefficient of the existing slit caisson breakwater.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.32 no.5
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• pp.331-339
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• 2020

In this study, ways to reduce the edge pressure at the bottom plate of the caisson breakwater were considered. The water depth, freeboard, design wave height and period, and the location of the center of gravity on the super-structure of the breakwater were selected as key design variables that influence the edge pressure, and analyzed how the edge pressure changes according to the change of this key variables. The pressure distribution formulae suggested in the design standard was applied for the calculation of design wave forces. Based on the wave forces, the required effective self-weight of the super-structure and the minimum width of the caisson were determined to have a safety factor of 1.2 against sliding and overturning. From the results, it was found that the edge pressure rapidly increased as the water depth increased, and could exceed the allowable bearing capacity when it reached a certain water depth which is 20 m within the analysis conditions. It was also confirmed that the edge pressure gradually increased linearly as the freeboard increased, but decreased with the increase of the wave height and period. This edge pressure could be significantly reduced up to more than 20% by moving the center of gravity of the super-structure to the seaside, which is 5% of the caisson width. Based on the analysis results and the recently conducted research results, a method was proposed to reduce the edge pressure that can be used in the design.