FLOOD04125

• County: Statewide
• Basin: Statewide
• Title: Interim Procedures for Evaluating Scour at Bridges
• Date: 9/1/1988
• Prepared By: Federal Highway Administration
• Floodplain - Doc Type: Educational/Technical/Reference Information

TABLE 4.1 SIJI"MARY OF AB\fT1IIENT SCOUR EQUATIONS

CASE AB\JllI1ENT OVERBANK VALUE OF BED LOAD ABUlMENT EQUATION
LOCATION FLOW a/y~ CONDITION TYPE NUleER
1 Projects into No a/y.. < 25 Live bed Vertical wall 5, I, 7
channe 1
Spill through 3, 6, 7
Clear water Vertical Wall 8
Spill through B
2 Projects into Yes a/y.. < 25 Live bed Not Designated 6, 10
channe 1
Clear water Not Designated 8, 10
3 Set back from Yes a/y.. < 25 Clear water Not Designated 8
main channel
4 Relief bridge Yes a/y.. < 25 Clear water Not Designated 8
on floodplain
5 Set at edge of Yes a/y.. < 25 Live bed Not Designated 10
main channel
6 Not designated Yes a/y.. > 25 Not Not designated 11
designated
7 Skewed to - - - - *
stream

* Adjust scour estimate for equations 3 - 11 using Figure 4.11.

26

I
I
f'
I
I
I
I
I
I
I
I I
I
I
I
I
I
I
I
I
I