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A review of the state of research on bridge pier scour under combined action of waves and current

Kumar Lalit, Afzal Mohammad Saud

Acta Geophysica

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2023

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Vol. 71, no. 5

2359--2379

EN

This article presents a review of the state of research on bridge pier scour under combined wave–current flow. The hydrodynamics and scour around the bridge pier under combined wave–current flow have been explained in detail based on the information available in the literature. The impact of relative flow velocity (Ucw), Keulegan–Carpenter number (KC), absolute Reynolds number (Rea), and sediment characteristics on bridge pier scour under combined wave–current flow is presented. This study includes physical modelling of scour with various formulations to predict scour depth and calculation procedures related to scour under combined wave–current flow in the coastal environment. In addition, this study also provides the development of numerical models to investigate bridge pier scour in detail. In the end, future prospects of hydrodynamics and scour around the bridge pier under combined wave–current flow are delineated.

2

Infuence of collars on reduction in scour depth at two piers in a tandem confguration

Memar Sargol, Zounemat-Kermani Mohammad, Beheshti Aliasghar, Rahimpour Majid, De Cesare Giovanni, Schleiss Anton J.

Acta Geophysica

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2020

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Vol. 68, no. 1

229--242

EN

Bridge failure, due to local scour at bridge pier foundations, has become a critical issue in river and bridge engineering, which might lead to transportation disruption, loss of lives and economic problems. A practical solution to prevent bridge collapses is the implementation of scour mitigation methods around bridge foundations. Based on an experimental perspective, this study is focused on the infuence of the size and position of circular collars from the sediment bed on scour depth at two tandem piers. To meet this end, long-lasting experiments are performed under clear-water conditions using uniform sand for bed materials. Compared to the adjacent position of the collar on the bed, placing the collars below the bed would increase the delay time of scour at the piers up to four times. However, regardless of the delay time, the observations indicate that locating the collars on the initial bed surface results in maximum reduction in scour depths around the piers. It was found that diminishing the fow intensity has a dramatic impact on the scour reduction at the piers, so that maximum reduction in scour depths at piers increased on average from 20 to 70% with the reduction in the fow intensity from 0.95 to 0.9.

3

Coherent structure dynamics and sediment particle motion around a cylindrical pier in developing scour holes

Link O., Gonzalez C., Gonzalez C., Maldonado M., Escauriaza C.

Acta Geophysica

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2012

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Vol. 60, no. 6

1689-1719

EN

Recent investigations on the dynamics of the turbulent horseshoe vortex system (THV) around cylindrical piers have shown that the rich coherent dynamics of the vortical structures is dominated by lowfrequency bimodal fluctuations of the velocity field. In spite of these advances, many questions remain regarding the changes of the flow and sediment transport dynamics as scour progresses. In this investigation we carry out laboratory experiments to register the development of the scour hole around a cylindrical pier in a fine-sand bed (d50 = 0.36 mm). We use the bathymetry measured in the experiment to simulate the flow field employing the detached-eddy simulation approach (DES), which has shown to resolve most of the turbulent stresses around surface-mounted obstacles. From these simulations we compare the dynamics of the THV to the flat-bed case, and analyze the effects on particle transport and sediment flux using the Lagrangian particle model of Escauriaza and Sotiropoulos (2011b) to study the impact of the changes of the flow on the sediment dynamics.