American Society of Civil Engineers

Time Scale for Local Scour at Bridge Piers

by Bruce W. Melville, (Assoc. Prof. in Civ. and Resour. Engrg., Univ. of Auckland, Auckland, New Zealand) and Yee-Meng Chiew, (Sr. Lect. in Civ. and Struct. Engrg., Nanyang Tech. Univ., Singapore 2263)

Journal of Hydraulic Engineering, Vol. 125, No. 1, January 1999, pp. 59-65, (doi:

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Document type: Journal Paper
Discussion: by Brian D. Barkdoll    (See full record)
Closure:(See full record)
Abstract: The temporal development of clear-water local scour depth at cylindrical bridge piers in uniform sand beds is considered. New data are presented and used to quantify the influence of flow duration on the depth of local scour. An equilibrium time scale (t*) is defined. The data show that both t* and the equilibrium scour depth (dse) are subject to similar influences of flow and sediment parameters, as might be expected because they are inherently interdependent. A method is given for determination of the time for development of dse for a given pier, sediment, and approach flow velocity and the concomitant estimation of the scour depth at any stage during development of the equilibrium scour hole. The results show that the scour depth after 10% of the time to equilibrium is between about 50% and 80% of the equilibrium scour depth, depending on the approach flow velocity.

ASCE Subject Headings:
Flow duration
Scale ratio
Time factors