Study on the Evaluation of Temporal Change in Horizontal and Vertical Tsunami Forces Acting on a Bridge Superstructure

Nakamura, Tomoaki; Sawa, Yutaro; Mizutani, Norimi

doi:10.1142/s0578563416400209

Cited by 11 publications

(7 citation statements)

References 9 publications

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“…The analytical equations were compared with large-scale experimental data, demonstrating their accuracy. Nakamura et al [18] conducted both hydraulic experiments and numerical simulations to study the tsunami wave forces on bridge superstructures, and concluded that using Morison's equation it was possible to estimate the horizontal force.…”

Section: Introductionmentioning

confidence: 99%

“…Apart from the experimental studies conducted to date (e.g., [11][12][13][14]16,[18][19][20][21][22][23]32]), the development of numerical solvers and the increased availability of high-performance computing (HPC) resources have provided an alternative efficient methodology for studying further the wave forces on coastal structures. Huang and Xiao [33] applied the Reynolds averaged Navier-Stokes (RANS) equations with the volume of fluid (VOF) method to investigate the dynamic impact of waves on the deck of the I-10 Escambia bay bridge.…”

Section: Introductionmentioning

confidence: 99%

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Assessment of Extreme Wave Impact on Coastal Decks with Different Geometries via the Arbitrary Lagrangian-Eulerian Method

Xiang

Istrati

2021

JMSE

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Given the documented wave-induced damage of elevated coastal decks during extreme natural hazards (e.g., hurricanes) in the last two decades, it is of utmost significance to decipher the wave-structure-interaction of complex deck geometries and quantify the associated loads. Therefore, this study focuses on the assessment of solitary wave impact on open-girder decks that allow the air to escape from the sides. To this end, an arbitrary Lagrangian-Eulerian (ALE) numerical method with a multi-phase compressible formulation is used for the development of three-dimensional hydrodynamic models, which are validated against a large-scale experimental dataset of a coastal deck. Using the validated model as a baseline, a parametric investigation of different deck geometries with a varying number of girders Ng and three different widths, was conducted. The results reveal that the Ng of a superstructure has a complex role and that for small wave heights the horizontal and uplift forces increase with the Ng, while for large waves the opposite happens. If the Ng is small the wave particles accelerate after the initial impact on the offshore girder leading to a more violent slamming on the onshore part of the deck and larger pressures and forces, however, if Ng is large then unsynchronized eddies are formed in each chamber, which dissipate energy and apply out-of-phase pressures that result in multiple but weaker impacts on the deck. The decomposition of the total loads into slamming and quasi-static components, reveals surprisingly consistent trends for all the simulated waves, which facilitates the development of predictive load equations. These new equations, which are a function of Ng and are limited by the ratio of the wavelength to the deck width, provide more accurate predictions than existing empirical methods, and are expected to be useful to both engineers and researchers working towards the development of resilient coastal infrastructure.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Assessment of Extreme Wave Impact on Coastal Decks with Different Geometries via the Arbitrary Lagrangian-Eulerian Method

Xiang

Istrati

2021

JMSE

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show abstract

“…The analytical equations were compared with largescale experimental data, demonstrating their accuracy. Nakamura et al [18] conducted both hydraulic experiments and numerical simulations to study the tsunami wave forces on bridge superstructures, and concluded that using Morison's equation it was possible to estimate the horizontal force.…”

Section: Introductionmentioning

confidence: 99%

“…Apart from the experimental studies conducted to date (e.g. [11][12][13][14], [16], [18][19][20][21][22][23], [32]), the development of numerical solvers and the increased availability of high performance computing (HPC) resources provided an alternative efficient methodology for studying further the wave forces on coastal structures. Huang and Xiao [33] applied the Reynolds averaged Navier-Stokes (RANS) equations with the volume of fluid (VOF) method to investigate the dynamic impact of waves on the bridge deck over the I-10 Es-cambia bay.…”

Section: Introductionmentioning

confidence: 99%

Assessment of Extreme Wave Impact on Coastal Decks with Different Geometries via the Arbitrary Lagrangian-Eulerian Method

Tao¹,

Istrati²

2021

Preprint

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Given the documented wave-induced damage of elevated coastal decks during extreme natural hazards (e.g. hurricanes) in the last two decades, it is of utmost significance to decipher the wave-structure-interaction of complex deck geometries and quantify the associated loads. Therefore, this study focuses on the assessment of solitary wave impact on open-girder decks that allow the air to escape from the sides. To this end, an arbitrary Lagrangian-Eulerian (ALE) numerical method with a multi-phase compressible formulation is used for the development of three-dimensional hydrodynamic models, which are validated against a large-scale experimental dataset of a coastal deck. Using the validated model as a baseline, a parametric investigation of different deck geometries with a varying number of girders Ng and three different widths, was conducted. The results reveal that the Ng of a superstructure has a complex role and that for small wave heights the horizontal and uplift forces increase with the Ng, while for large waves the opposite happens. If the Ng is small the wave particles accelerate after the initial impact on the offshore girder leading to a more violent slamming on the onshore part of the deck and larger pressures and forces, however, if Ng is large then unsynchronized eddies are formed in each chamber, which dissipate energy and apply out-of-phase pressures that result in multiple but weaker impacts on the deck. The decomposition of the total loads into slamming and quasi-static components, reveals surprisingly consistent trends for all the simulated waves, which facilitates the development of predictive load equations. These new equations, which are a function of Ng and are limited by the ratio of the wavelength to the deck width, provide more accurate predictions than existing empirical methods, and are expected to be useful to both engineers and researchers working towards the development of resilient coastal infrastructure.

show abstract

“…Based on the analysis, they proposed a new method for estimating the maximum horizontal, maximum downward vertical, and maximum uplift forces. Nakamura et al [5] investigated the tsunami-induced pressure and load acting on a bridge superstructure using hydraulic model experiments and numerical simulations based on the hydraulic model. They used the results to propose estimation formulas for the temporal changes in the horizontal and vertical forces.…”

Section: Introductionmentioning

confidence: 99%

Mechanism of Tsunami-Induced Erosion of Bridge-Abutment Backfill and Its Countermeasures

Nakamura

Sugiyama

Cho

et al. 2021

Water

Self Cite

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Tsunamis can destroy bridges in coastal areas. Studies have attempted to unravel the mechanism of tsunami-induced damage and develop effective countermeasures against future tsunamis. However, the mechanisms of tsunami-induced erosion of bridge-abutment backfill and its countermeasures have not been studied adequately. This study investigates this topic using numerical analysis. The results show that the tsunami flowing down along the downstream wing of the abutment induces bedload sediment transport on the ogive section of the backfill on the downstream side of the abutment, resulting in the onset of backfill erosion. Sediment suspension and bedload sediment transportation occur when the backfill inside the abutment starts to flow out from below the downstream wing. This leads to subsidence of the backfill at the upstream side of the downstream wing. The subsequent backfill erosion is mainly caused by bedload sediment transport. Numerical experiments on countermeasures show that extending the wings downward can prevent the acceleration of backfill erosion in the presence of the abutment. A combination of multiple countermeasures, including extended wings, would be more effective in maintaining the stability of the abutment after a tsunami. This suggests the application of such countermeasures to actual bridges as an effective countermeasure against backfill erosion.

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Study on the Evaluation of Temporal Change in Horizontal and Vertical Tsunami Forces Acting on a Bridge Superstructure

Cited by 11 publications

References 9 publications

Assessment of Extreme Wave Impact on Coastal Decks with Different Geometries via the Arbitrary Lagrangian-Eulerian Method

Assessment of Extreme Wave Impact on Coastal Decks with Different Geometries via the Arbitrary Lagrangian-Eulerian Method

Assessment of Extreme Wave Impact on Coastal Decks with Different Geometries via the Arbitrary Lagrangian-Eulerian Method

Mechanism of Tsunami-Induced Erosion of Bridge-Abutment Backfill and Its Countermeasures

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