online_contraction_scour_live_bed:  Contraction scour under live bed conditions
using modified Laursen 1960 equation

Modified Laursen formula

ys / y1 = ( Q2 / Q1 ) 0.86 (W1 / [W2) k1  -  ( yo / y1 )

[ yo, y1, Q and W in any consistent set of units ]
[ S1 in m/m or ft/ft ]
[ T in °C or °F ]
[ D50 in mm or ft ]

Reference:

Evaluating Scour at Bridges, FHWA Hydraulic Engineering Circular No. 18,
 Fifth Edition, 2012.

INPUT DATA:      [Description]     [Sample Input]

Select:      

Mean flow depth below the bridge, before scour yo :      

 

Mean flow depth upstream of the bridge y1 :      

 

Discharge upstream of the bridge (only in the main channel) Q1 :      

 

Discharge in the contracted section Q2 :      

 

Bottom width in the section upstream of the bridge W1 :      

 

Bottom width in the contracted section, excluding piers W2 :      

 

Energy slope in the main channel upstream S1 :      

 

Median diameter of the bed material D50 :      

 

Select water temperature T :      

OUTPUT:

SI units (metric)
Water temperature T: 0°C

Contraction scour depth
under live bed conditions
ys :     

Press button to
or recalculate

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