Effect of Angle between Pier and Center of River Flow on Local Scouring around the Bridge Pier

Kadono, Takuma; Okazaki, Shinichiro; Kabeyama, Yoshihiro; MATSUI, Toshinori

doi:10.3390/w12113192

Cited by 3 publications

(5 citation statements)

References 17 publications

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“…Further, in Case 13, the range of the local scour hole formed upstream of the bridge pier model increased as the water level rose and fell iteratively, and the local scouring extended downstream of the oval specimen more widely than that when θ = 30 • at the left side. This tendency was similar to that of the experiments previously conducted by the authors and other researchers [16][17][18]. From these figures, it can be observed that the local scour depth increases as the water level rises and falls iteratively, and that the increase tends to converge after the third or fourth water flow.…”

Section: Progression Of the Local Scour Areasupporting

confidence: 90%

“…Figures [13][14][15][16][17][18] show the changes in the local scour length obtained from the experiment. The local scour extension shown in the figures is the distance from the starting point of the pier model to the point where the ground level reaches the surface of the soil layer in the measurement direction.…”

Section: Effect Of Water Level History and Pier Shape On Local Scour Lengthmentioning

confidence: 99%

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Effects of Dynamical Change in Water Level on Local Scouring around Bridge Piers Based on In-Situ Experiments

Kadono

KATO

Okazaki

et al. 2021

Water

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To evaluate the stability of bridge piers affected by the local scouring, the existing formulas for estimating the maximum local scour depth have been developed based on the results of experiments conducted under a constant water level. However, the applicability of these formulas to the cases where the water level rises and falls, such as a water level change in a real river, is not clear. In this study, water flow experiments were conducted on cylindrical and oval bridge pier models to investigate the effect of iterated water level change on the progression of local scour around piers. Results of experiments with cylindrical and oval pier showed that the local scour depth and length increased by an iterated action of the water level change; however, these values converged after the number of iterated actions reached a certain time. The local scour length at upstream of the bridge pier was approximately 1.8 times larger than the theoretical value, which was calculated through the local scour depth and angle of repose in water. The local scour length is an important parameter for defining the streambed protection zone, which is one of the measures against local scour, and we showed that the streambed protection zone needs to be defined more widely.

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Section: Progression Of the Local Scour Areasupporting

confidence: 90%

Section: Effect Of Water Level History and Pier Shape On Local Scour Lengthmentioning

confidence: 99%

Effects of Dynamical Change in Water Level on Local Scouring around Bridge Piers Based on In-Situ Experiments

Kadono

KATO

Okazaki

et al. 2021

Water

Self Cite

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show abstract

“…The potential techniques also showed by Bento et al (2018), which used Kinect sensor and closerange photogrammetry for semi rounded shape scour modelling that most common used in Portugal. Previous studies have been researched to investigate the flow pattern and scouring by modelling software (Ali et al, 2017;Kadono et al, 2020;Lee et al, 2019). Therefore, it is of utmost importance to consider different types of pier shapes and determine the most suitable pier geometry in terms of reducing scour (Al-Shukur & Obeid, 2016;Melville, 1997;Murtaza et al, 2018;Török et al, 2017).…”

Section: Introductionmentioning

confidence: 99%

Study of Pillar Dimension Variations Modelling on River Geomorphology

Muhardiono

2023

jpensil

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The behavior of river flow patterns on the condition of the pillar dimensions can affect the geomorphology conditions of the river, namely the unbalanced local scouring between sediment transport and sediment supply so that it will affect the strength of the pillar. This study aims to study the effect of pillar dimensions on scour depth and channel base changes in the pillar area. The method of observation was carried out by simulations using Nays2DH with the same parameters for each test of each dimension with discharge (Q) = 0.5 m3/s, sediment diameter (D50) = 0.35 mm, channel width (B) = 5 m, channel length (L) = 25 m, slope (i) = 0.005 and drainage time (t) = 7200 s. The simulation results show the basic scour pattern of the channel which has the smallest value, the diamond type pillar. Degradation - Basic channel agitation on diamond type pillars, showing a pattern that tends to be evenly distributed compared to semi rounded, rectangle, or octagonal types. Period (t) 7200 s downstream of the pillar, semi rounded type scours change <0.3 m, rectangle type scours changes <0.4 m, octagonal type scours changes <0.4 m, and diamond type scours changes <0.2 m. So the dimensions of the diamond type are more effective in reducing the depth of scour.

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“…Yang et al 19 experimentally investigated the scour on a single elongated rectangular shaped slab pier skewed into a shallow stream. Through experiments on a thick rectangular pier, Kadono et al 20 showed that the scour area is enlarged when skew is toward the river flow, considering the collapse of a railroad bridge. Sato 6 experimentally investigated the effect of a skewed spindle shape on the scour and water level changes.…”

Section: Introductionmentioning

confidence: 99%

“…Notably, structures, such as piles, placed below the bottom of the pier may influence the scour depth 17 , 18 . In addition, the degree of scour is more severe when the pier is skewed relative to the center of flow, regardless of the installation or hydraulic conditions 6 , 20 , 21 . In practice, a combination of several conditions affect the pier structure rather than the independent action of single factors.…”

Section: Introductionmentioning

confidence: 99%

Model experiments on hydraulic properties around multiple piers with reproduced 3D geometries

Sato

2022

Sci Rep

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The effects of multiple piers with 3D geometries on water levels during floods, as well as riverbed fluctuations and local scour after floods were examined via hydraulic model experiments. The Kintaikyo Bridge in Japan, a world-famous historical triple-wooden-arch bridge, was modeled at a scale of approximately 1/276. The number of model piers was set to four, as in the real bridge, and they were 3D printed and installed in the sand layer of an open channel. To provide adequate information on the pier installation conditions and hydraulic response, four cases were studied in the experiments, primarily considering present pier conditions; the previous conditions of the Kintaikyo Bridge were also considered. The experimental conditions in these four cases depended on whether foundations were present, the piers were skewed against the flow center, and the shape was spindle or similar to that of the present case. In the current bridge condition where foundations are present and there is no skew, water level rise, riverbed fluctuation, and local scour were suppressed. Furthermore, the statistical analysis of the results suggested that riverbed fluctuations are more stable after flooding. The two piers with foundations had smaller scour areas than those without. Further, those with foundations generally had lower mean scour at the pier perimeters. Regarding those without foundations, there were no differences in riverbed fluctuations or local scour due to the skewed pier angle. In addition, the representative length of the pier with a 3D geometry was determined by dividing the projected area of the pier below the initial sand surface in the main flow direction by the pier height, and the relationship between the Froude number or the mean water depth and the maximum scour depth was investigated.

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Effect of Angle between Pier and Center of River Flow on Local Scouring around the Bridge Pier

Cited by 3 publications

References 17 publications

Effects of Dynamical Change in Water Level on Local Scouring around Bridge Piers Based on In-Situ Experiments

Effects of Dynamical Change in Water Level on Local Scouring around Bridge Piers Based on In-Situ Experiments

Study of Pillar Dimension Variations Modelling on River Geomorphology

Model experiments on hydraulic properties around multiple piers with reproduced 3D geometries

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