FLOOD03064

• County: Statewide
• Basin: Statewide
• Title: Evaluating Scour at Bridges
• Date: 11/1/1990
• Prepared By: Federal Highway Administration
• Floodplain - Doc Type: Floodplain Report/Masterplan

developed computer software for the analysis of flow
through bridges a~d of scour, There currently is a
contract for the jevelopment of software to determine total
scour at a bridge crossing. This effort should continue.
In addition, the ~aintenance, support and improvement of
existing and future software should be provided on a
continual basis,

4. Laboratorv Studies of Scour. There is a need for
laboratory studies to determine specific scour processes
and to develop scour countermeasur~s. Only through
controlled experiments can the effect of the variables and
parameters associated with scour be determined. Scour
prediction equations can then be improved and design
methods for additional countermeasures can be developed.

Some examples of needed laboratory research are:

a. Improved prediction of the effect of flow angle of
attack against a pier or abutment on scour depth,

b. Improved knowledge of the effect of flow depth and
velocity on scour depths,

c. Determine the effect of the pile cap or footing on
depth of scour,

d. Determine the magnitude of decrease in scour depth
likely to occur if there are large sediment particles
in the bed material (arrnoring of the scour hole) ,

e. Determine coefficients for the abutment scour equations
to replace tte simplistic use of abutment length,

f. Determine the width of scour hole as a function of
scour depth and bed material size,

g. Determine ho.' to estimate contraction scour when
abutments are, set back from the channel and there is
overbank flo.',

h. Fundamental research on the mechanics of scour,

i. Determine thE' mechanics of tidal scour,

j. Determine the size and placement of riprap (elevation,
width and location) in the scour hole needed to protect
piers and abutments,

k. Determine met:hods to predict scour depths associated
with pressure flow,

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