Temporal Development of Local Scour Around Bridge Pier

Because of the problem of local scour caused by the change of the flow structure caused by the water-resistance of the column bridge pier, the theoretical analysis, and indoor water tank test were used to study the effect of installing a new anti-scouring device in front of the bridge pier on the local scour reduction effect; the influence of the main design parameters such as the height of the protective device, the angle of the protective device and the distance from the protective device to the bridge pier on the local scour of the bridge pier was selected, and the optimal parameter design combination was selected. The test results show that: under the same water flow conditions, the maximum scour depth reduction rate of the measuring point under the protection of the protective device is 48.4% to 74.2% compared with the unprotected scour; the reduction rate of the bridge pier is relative to the relative height of the device and the device equivalent. The angle and the distance between the device and the bridge pier are related, and the shock reduction rate decreases with the increase of the flow intensity. In the test range, the ratio of the device height to the water depth is 2/3, the device angle is 60 °, and the distance from the bridge pier is 3. When the diameter of the pier is doubled, the effect of reducing the impact on the pier is the best.

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Clear-water local scour at wide piers in shallow-water flow

Water Practice & Technology ◽

10.2166/wpt.2014.035 ◽

2014 ◽

Vol 9 (3) ◽

pp. 331-343 ◽

Cited By ~ 3

Author(s):

N. Ahmad ◽

T. Mohamed ◽

F. H. Ali ◽

B. Yusuf

Keyword(s):

Laboratory Data ◽

Local Scour ◽

The Other ◽

Scour Depth ◽

Temporal Development ◽

Clear Water ◽

Shallow Water Flow ◽

Equilibrium Time ◽

Sediment Size ◽

Flow Intensity

Laboratory data for local scour depth regarding the size of wide piers are presented. Clear water scour tests were performed for various pier widths (0.06, 0.076, 0.102, 0.14 and 0.165 m), two types of pier shapes (circular and rectangular) and two types of uniform cohesionless bed sediment (d50 = 0.23 and d50 = 0.80 mm). New data are presented and used to demonstrate the effects of pier width, pier shape and sediment size on scour depth. The influence of equilibrium time (te) on scouring processes is also discussed. Equilibrium scour depths were found to decrease with increasing values of b/d50. The temporal development of equilibrium local scour depth with new laboratory data is demonstrated for flow intensity V/Vc = 0.95. On the other hand, the results of scour mechanism have shown a significant relationship between normalized volume of scoured and deposited with pier width, b. The experimental data obtained in this study and data available from the literature for wide piers are used to evaluate predictions of existing methods.

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Local scour depth at a bridge pier protected by a collar in steady and unsteady flow

Proceedings of the Institution of Civil Engineers - Water Management ◽

10.1680/jwama.18.00061 ◽

2019 ◽

Vol 172 (6) ◽

pp. 301-311 ◽

Cited By ~ 4

Author(s):

Mojtaba Karimaei Tabarestani ◽

Amir Reza Zarrati

Keyword(s):

Unsteady Flow ◽

Local Scour ◽

Bridge Pier ◽

Scour Depth

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Experimental Investigation of Local Scour Protection for Cylindrical Bridge Piers Using Anti-Scour Collars

Water ◽

10.3390/w11071515 ◽

2019 ◽

Vol 11 (7) ◽

pp. 1515 ◽

Cited By ~ 6

Author(s):

Shunyi Wang ◽

Kai Wei ◽

Zhonghui Shen ◽

Qiqi Xiang

Keyword(s):

Protective Effect ◽

Local Scour ◽

Bridge Pier ◽

Bridge Piers ◽

Experimental Program ◽

Design Parameters ◽

External Diameter ◽

River Sand ◽

Bed Scour ◽

Scour Protection

Local scour of bridge piers is one of the main threats responsible for bridge damage. Adopting scour countermeasures to protect bridge foundations from scour has become an important issue for the design and maintenance of bridges located in erodible sediment beds. This paper focuses on the protective effect of one active countermeasure named an “anti-scour collar” on local scour around the commonly used cylindrical bridge pier. A cylindrical pier model was set up in a current flume. River sand with a median particle size of 0.324 mm was selected and used as the sediment in the basin. A live-bed scour experimental program was carried out to study the protective effect of an anti-scour collar by comparing the local scour at a cylindrical bridge pier model with and without collar. The effects of three design parameters including collar installation height, collar external diameter and collar protection range, on the scour depth and scour development were investigated parametrically. According to the experimental results, it can be concluded that: the application of an anti-scour collar alleviates the local scour at the pier effectively; and the protection effect decreases with an increase in the collar installation height, but increases with an increase in the collar external diameter and the protection range. Design suggestions for improving the scour protective effect of the anti-scour collar are summarized and of great practical guiding significance to the development of anti-scour collars for bridge piers.

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