Experimental Study on Scour at a Sharp-Nose Bridge Pier with Debris Blockage

Ebrahimi, Mohsen; Kripakaran, Prakash; Prodanović, Dušan; Kahraman, Recep; Riella, M.; Tabor, Gavin; Arthur, Scott; Djordjević, Slobodan

doi:10.1061/(asce)hy.1943-7900.0001516

Cited by 47 publications

(55 citation statements)

References 45 publications

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“…The volume of scour was seen to decrease quadratically with ds, following the equation Vs = 1.6ds 2 , where Vs and ds are in cubic meters and centimeters, respectively. This equation has a similar form to the equation proposed by Ebrahimi et al [52], i.e., Vs = 2.2ds 2 , where Vs and ds are in cubic meters and centimeters, respectively, for scour at a sharp nose pier in the presence of debris. This information can be useful in planning post-flood remedial works (e.g., Solaimani et al [53]) where often only maximum scour depth is initially measured.…”

Section: Volume Of Scour Holementioning

confidence: 71%

Impact Assessment of Pier Shape and Modifications on Scouring around Bridge Pier

Farooq

Ghumman

2019

Water

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Previous experimental research on utilizing pier modifications as countermeasures against local scour has focused primarily on circular pier. It is of utmost importance to further investigate the most suitable pier shape for pier modification countermeasure separately and in combination. This experimental study aims to reduce the stagnation of the flow and vortex formation in front of the bridge pier by providing a collar, a hooked collar, a cable, and openings separately and in combination around a suitable pier shape. Therefore, six different pier shapes were utilized to find out the influence of pier shape on local scouring for a length-width ratio smaller than or equal to 3. A plain octagonal shape was shown as having more satisfactory results in reducing scour compared to other pier shapes. Furthermore, the efficiency of pier modification was then evaluated by testing different combinations of collar, hooked collar, cable, and openings within the octagonal bridge pier, which was compared to an unprotected octagonal pier without any modification. The results show that by applying such modifications, the scour depth reduced significantly. The best combination was found to be a hooked collar with cable and openings around an octagonal pier. It was revealed that the best combination reduced almost 53% of scour depth, as compared to an unprotected octagonal pier.

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Section: Volume Of Scour Holementioning

confidence: 71%

Impact Assessment of Pier Shape and Modifications on Scouring around Bridge Pier

Farooq

Ghumman

2019

Water

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“…As shown by Melville and Dongol (1992), Lagasse et al (2010) and Ebrahimi et al (2018), flow depth h and pier diameter D, have appreciable effect on the change of scour depth due to debris. Therefore, using Buckingham's π Theorem, the following function can be written to explain the relationship between variables…”

Section: Proposed Methodsmentioning

confidence: 93%

“…The method for computing is derived from experimental data available from three sources in literature - Ebrahimi et al (2018), Lagasse et al (2010) and Melville and Dongol (1992). Another available source of experimental data is the work of Pagliara and Carnacina (2011a).…”

Section: Data From Flume Experimentsmentioning

confidence: 99%

“…The approaches are applicable only to the scenario of debris located just under the flow free surface. Although this is the worst case scenario with respect to scour depth as shown by Ebrahimi et al (2018), debris, in reality, can also be fully submerged or be located on the stream bed.…”

mentioning

confidence: 99%

“…The equation for computing the debris factor is derived using multiple linear regression analysis on data from inhouse flume experiments (Ebrahimi et al 2018) and other reliable experimental data available in literature (Melville andDongol 1992 andLagasse et al 2010). To facilitate the application of the proposed debris factor method, families of charts are also provided to directly estimate the debris factor using debris dimensions and its elevation in water column.…”

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confidence: 99%

See 2 more Smart Citations

A method for evaluating local scour depth at bridge piers due to debris accumulation

Ebrahimi

Djordjević

Panici

et al. 2020

Proceedings of the Institution of Civil Engineers - Bridge Engi

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This paper introduces a novel method for evaluating the effect of debris accumulation on local scour depth at bridge piers. The concept of a debris factor is proposed to replace the current effective and equivalent pier width approaches that have been shown to overestimate debris-induced scour in many instances. The concept enables a simpler, more direct and realistic estimation of the change in local scour depth due to debris since it accounts for (i) debris length (streamwise), width (spanwise) and thickness (depth wise), and (ii) the influence of debris elevation in flow, i.e. is applicable for free-surface debris, submerged debris, or debris resting on the stream bed. The concept works with all existing local scour equations alongside other factors that influence scour depth such as flow angle of attack and pier shape. The mathematical model that underpins the proposed concept is derived through multiple linear regression on experimental data obtained at Exeter and elsewhere. The proposed method is shown to improve accuracy by at least 24% and 5% in comparison to the effective and equivalent pier width approaches, respectively. More importantly, the method is shown to be robust, providing highly consistent results with significantly less uncertainty.

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