Tsunami Induced Forces in Bridges: Large-Scale Experiments and the Role of Air-Entrapment

Istrati, Denis; Buckle, Ian G.; Lomónaco, Pedro; Yim, Solomon C.; Itani, Ahmad M.

doi:10.9753/icce.v35.structures.30

Cited by 21 publications

(10 citation statements)

References 7 publications

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“…While the majority of the numerical studies focused on two-dimensional (2D) models, some of them pointed out that the interaction between a deck and the wave is not a completely two-dimensional process, especially when (i) the deck has diaphragms that trap the air [43][44][45], (ii) the elevated slab has air-vents [19], (iii) the deck is skewed [46][47][48], (iv) the wave is oblique [46] or (v) water-borne debris is trapped in front of the deck at an off-center location [49]. For example, Bozognia and Lee [43] showed that simplified 2D simulations of periodic waves impacting a concrete deck with diaphragms, could not represent the motion of air in the longitudinal direction.…”

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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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%

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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“…It should be noted that the air and water are assumed as incompressible flows in the established numerical model. The trapped air has a critical role and increases the uplift forces [32][33][34][35][36], as well as the overturning moment [34] on the bridges. Moreover, refs.…”

Section: Model Setups and Boundary Conditionsmentioning

confidence: 99%

“…Moreover, refs. [35] and [36] indicated the generation of three-dimensional effects even in the case of a normal wave impact on a straight bridge (without any obliqueness) due to the tendency of the air to move in the 3rd direction. The effects of trapped air may be mitigated by setting air venting holes.…”

Section: Model Setups and Boundary Conditionsmentioning

confidence: 99%

3D Numerical Modeling and Quantification of Oblique Wave Forces on Coastal Bridge Superstructures

Jia¹,

Zhu

Dong

2022

JMSE

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Simply supported bridges comprise the majority of bridge systems in coastal communities and are susceptible to severe damage from extreme waves induced by storms or tsunamis. However, the effects of oblique wave impacts have been less investigated due to the lack of appropriate numerical models. To address this issue, this study investigates the effects of wave incident angles on coastal bridge superstructures by developing an advanced computational fluid dynamics (CFD) model. Different wave scenarios, including wave height, relative clearance, incident angle, and wavelength are tested. It is found that the maximum wave forces in the horizontal and longitudinal directions could reach 1901 and 862 kN under extreme conditions, respectively, destroying bearing connections. Three surrogate models, i.e., the Gaussian Kriging surrogate model, the Artificial Neural Network (ANN), and the Polynomial Chaos Expansion (PCE), are established by correlating the wave parameters with the maximum wave forces. Through comparisons among the three surrogate models, it is found that the 3-order PCE model has better performance in predicting loads in vertical and horizontal directions, while the ANN model is more suitable for results in the longitudinal direction. This study contributes to the optimized design of coastal bridges and also offers an opportunity for future studies to investigate hazard damage-mitigation measures.

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“…While the majority of the numerical studies focused on two-dimensional (2D) models, some of them pointed out that the interaction between a deck and the wave is not a completely two-dimensional process, especially when (i) the deck has diaphragms that trap the air [44][45][46], (ii) the elevated slab has air-vents [19], (iii) the deck is skewed [47][48][49] (iv) the wave is oblique [49], or (v) water-borne debris is trapped in front of the deck at an off-center location [50]. For example, Bozognia and Lee [44] showed that simplified 2D simulations of periodic waves impacting a concrete deck with diaphragms, could not represent the motion of air in the longitudinal direction.…”

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

Self Cite

View full text Add to dashboard Cite

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

Tsunami Induced Forces in Bridges: Large-Scale Experiments and the Role of Air-Entrapment

Cited by 21 publications

References 7 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

3D Numerical Modeling and Quantification of Oblique Wave Forces on Coastal Bridge Superstructures

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

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