Estimation of maximum scour depths at upstream of front and rear piers for two in-line circular columns

Keshavarzi, Alireza; Shrestha, Chij Kumar; Melville, Bruce W.; Khabbaz, Hadi; Ranjbar-Zahedani, Mohsen; Ball, James E

doi:10.1007/s10652-017-9572-6

Cited by 46 publications

(18 citation statements)

References 35 publications

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“…investigated experimentally of twin piers, it was found that the scour depth for the first pier was higher than the second pier [19]. Keshavarzi et al (2018) made experimental investigation of interaction of two piers (L/D) from zero to twelve where L spacing between two piers from center to center and D the diameter of the pier with different flow intensities, it was found that the scour depth when the spacing 1< L/D< 2.5 increases, in the same meaning when the spacing increases the scour depth at upstream of the front pier increases [20]. Vikas et al investigated experimentally of using a collar plate at bed level of different sizes, the larger size was three times the diameter of pier and gave zero scour depth, also it was studied the using of triple collar with different spacing between them, it was found when the spacing between collar (D/6) reduces the scour by 84 % comparing with the pier without any protection [21].…”

Section: Introductionmentioning

confidence: 98%

Optimum Design for Controlling the Scouring on Bridge Piers

Al-Shukur

Ali

2019

Civ Eng J

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The scouring around bridge pier can be considered the most important reasons of bridge failure. Therefore, we investigated by using physical models of piers and we used single pier with square collar , circular collar and interaction of two piers in laboratory channel, its width 1 m and applied three velocities (0.1, 0.08, and 0.07) m/sec. This experimental investigation was made to choose the optimum shape and location of collar of single pier and comparing it with the interaction of two piers, the results showed that both square and circular collar decrease the scour depth, but the square collar is more effective of reducing scouring and the best location at bed level for single pier, comparing the results of single pier with the interaction of two piers, the interaction of two piers without any countermeasure reduced scour depth about 58%.

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Section: Introductionmentioning

confidence: 98%

Optimum Design for Controlling the Scouring on Bridge Piers

Al-Shukur

Ali

2019

Civ Eng J

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“…The scour processes at pier groups are more complicated because of the interaction of the flow structures and consequently, the scour pattern differs from that of a single pier. Local scouring around bridge pier groups in cohesionless soil beds was investigated in researches of [1][2][3][4][5][6][7][8][9][10][11][12][13]15]. Laursen and Toch [1] presented the scour patterns at the foundation of two bridge piers arranged in-line and parallel to the flow direction, they observed that the scope of scour cultivates as the two piers orientation diverges from the approach flow direction.…”

Section: Introductionmentioning

confidence: 99%

Effect of Interaction between Bridge Piers on Local Scouring in Cohesive Soils

2020

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Local scour at the piers is one of the main reasons of bridge foundation undermining. Earlier research studies focused mainly on the scour at a single bridge pier; nevertheless, modern designs of the bridges comprise wide-span and thus group of piers rather than a single pier are usually used to support the superstructure. The flow and scour pattern around group of piers is different from the case of a single pier due to the interaction effect. Reviewing the literature of local scour around bridge piers group revealed that the local scour around bridge piers group founded in cohesive soil bed was not investigated, and most of the scour studies were related to scour in cohesionless soils. The objective of the present study is to investigate the effect of the interaction between two in-line (tandem) circular bridge piers of variable spacings founded in cohesive soil on the local scour. A set of laboratory flume experiments were conducted under the clear-water scour condition to investigate this effect. This study is the first that investigates experimentally the scour around group of bridge piers in cohesive bed. It was found that the maximum scour depth at the upstream pier of the two in-line piers occurred at a spacing of two times the diameter of the pier, scour at the downstream pier was reduced due to a sheltering effect, the interference effect will be reduced for pier spacings larger than three times of the pier diameter. A recent pier scour equation was used to estimate the scour depths at the two in-line piers in cohesive soil and compare the estimated value with the measured scour depths in the laboratory. The comparison indicated that the proposed scour equation overestimates the scour depths at both the upstream and the downstream pier.

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“…Pier-scour is caused by the interference of the pier with the flow and characterised by the formation of the scour hole immediately around the pier. Numerous studies have been conducted to understand the mechanism of pier-scour (e.g., Melville and Raudkivi [2], Ahmed and Rajaratnam [3], Ettema et al [4], Keshavarzi et al [5][6][7]). According to Melville and Coleman [1], there are four principal features of the flow structure around a single bridge pierdown-flow, horseshoe vortices, surface rollers, and wake vortices.…”

Section: Introductionmentioning

confidence: 99%

Flow Structures Around a Circular Bridge Pier with a Submerged Prism at Upstream

Zahedani¹,

Keshavarzi²,

Khabbaz³

et al. 2019

World Congress on Civil, Structural, and Environmental Engineering

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Previous investigations have indicated that local scour around bridge piers and abutments causes around 60% of waterway bridge failures. In order to decrease the potential of pier-scour failure, the authors previously proposed an upstream prism as a new countermeasure against local scour. The proposed prism was examined in a comprehensive experimental program to find the most efficient size, submergence ratio, and installation location of the prism. The experimental results showed that the submerged prism could reduce around 40% of the maximum scour depth, and 60% of the scour-hole volume. In this study, in order to find out how this submerged prism affects the flow structure around the pier and reduces the pier-scour, the flow structure analysis was conducted using particle image velocimetry (PIV). The velocity components were measured for two cases of a single circular pier with and without the submerged prism. Analysis of the results indicated that the proposed prism could change the flow structure at the upstream and downstream of the pier. In fact, this submerged prism formed a wake region behind itself, and the bridge pier was located at this wake region. The produced wake resisted the down-flow at the upstream side of the pier and also disturbed the formation of the horseshoe vortices around the pier. In addition, this submerged prism reduced the strength of wake vortices behind the pier. Consequently, the pier-scour was significantly reduced by the substantial changes in the flow structure.

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Estimation of maximum scour depths at upstream of front and rear piers for two in-line circular columns

Cited by 46 publications

References 35 publications

Optimum Design for Controlling the Scouring on Bridge Piers

Optimum Design for Controlling the Scouring on Bridge Piers

Effect of Interaction between Bridge Piers on Local Scouring in Cohesive Soils

Flow Structures Around a Circular Bridge Pier with a Submerged Prism at Upstream

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