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

I
I~,
,'-,f;!
\,- ~'" "
--
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I

EXHIBIT IlI-A

SCOUR PREDICTION EQUATIONS AS PER FHVA DRAFT ADVISORY

THIS PROGRAK WILL GENERATE CONTRACTION AND LOCAL . ABUTKENT
AND PIER SCOUR DEPTHS FoR !tOST CASES. RELIEF BRlDGE CASES WILL
NOT WRIt.

IN1'1lT THE DATA KNOWN FOR THE CASE. IF NOT APPLICABLE INSERT 'N/A'
IF THEN AN ERROR 'ERR' IS INDICATED THIS SHOUlJ) BE INVESTIGATED
AND GENERALLY IGNORED.

THE RELATIONSHIP BETIIEEN SHEAR STRESS TAU 1 AND TAU C lIAS
NOT BEEN USED IN THESE COKPUTATIONS, AND THEREFORE IT IS THE
RESPONSIBILTY OF THE TECH/ENGINEER TO DETERltINE WETHER THIS
IS APPLICABLE OR NOT IN AN'{ INDIVIDUAL SITIlATION.

INPUT THE DATA ON THE NEXT PAGE - "PgDn" KEY.
-BE SURE TO PRESS "F9" TO CALCUlATE THE IlORltSHEET BEFORE PRINTING
THE lAURSEN AND TOCH EQUATION IS NOT GIVEN IN THE FmlA ADVISORY.
INPUT THE DATE STARTING WITH MONTH EG 'MAll'
IN CASE AN ERROR MESSAGE APPEARS PRESS "Esc. AND RETYPE.
TO CALCUlATE .F9. TO PRINT DATA" Alt I. TO PRINT RESULTS" A1t P

TITLE: BRIDGE. DATE:
ALL INPUTS @ DISCHARGE: QSO Q100 QSOO
IF LEFT FLO\l IS OVERBANK (CASE 4),
ENTER 1 OTHERWISE ENTER 2
IF RIGHT FLO\l IS OVERBANK (CASE 4),
ENTER 1 OTHER\l1SE ENTER 2
LEn OVERBANK FLO\l DISCHARGE Qo
LEn OVERBANK FLO\l DEPTH Yo
WIDTH OF HAIN CHANNEL III
RIGHT OVERBANK FLO\l DISCHARGE Qo
RIGHT OVERBANK FLOW DEPTH Yo
FLO\l IN HAIN CHANNEL Qc
CONTRACTED SCOUR INPUTS
WIDTH OF HAIN CHANNEL III
WIDTH OF CONTRACTED CHANNEL W2
FLO\l IN CONTRACTED CHANNEL Qt
FLOIl IN HAIN CHANNEL Qc
MANNING FOR CONTRACTED CHANNEL N2
M.'.~mIG FOR Il" TN CHANNEL N1

ABUT & PIER SCOUR INPUTS:
ABUT AND EMBANK. LENGnl RIGHT A1
ABUT AND EMBANK. LENGTH LEFt A2
UPSTREAK VELOCITY V1
AVERAGE UPSTREAM FLO\l DEPTH Yl

PIl!I. \l1DTH B
C FACTOR FOR PIER SHAPE K1
C FACTOR FOR FLO\l ANGLE K2
ENTER 1 FOR SPL SLP ABUT, 2 FOR VERT
PRESS "19" KEY TO PERFORM COMPUTATION NOll! "19"

B-9