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

TABLE of CONTENTS

INTRODUCTION . , . . . . . . .
PURPOSE , , . . . . . . .
ORGANIZATION OF THIS CIRCULAR
BACKGROUND . . . , . . . . . .
OBJECTIVES OF A BRIDGE SCOUR EVALUATION PROGRAM
IMPROVING THE STATE-OF-PRACTICE OF ESTIMATING SCOUR
BRIDGES . . . . . . . , . . .

BASIC CONCEPTS AND DEFINITIONS OF SCOUR

GENERAL , , . . . . , . . ,
TOTAL SCOUR . . . . . . . .
AGGRADATION AND DEGRADATION
CONTRACTION SCOUR
LOCAL SCOUR . . . , , . . .
CLEAR-WATER AND LIVE-BED SCOUR
LATERAL SHIFTING OF A STREAM

DESIGNING BRIDGES TO RESIST SCOUR
DESIGN PHILOSOPHY AND CONCEPTS
DESIGN PROCEDURE . . . . , . .
CHECKLIST OF DESIGN CONSIDERATIONS

ESTIMATING SCOUR AT BRIDGES
INTRODUCTION . . . . .
DESIGN APPROACH , . .
DETAILED PROCEDURES
DETERMINING SCOUR ANALYSIS VARIABLES
ANALYSIS OF LONG-TERN BED ELEVATION CHANGE
EVALUATE THE SCOUR ANALYSIS NETHOD
CONTRACTION SCOUR . . . . . .
LOCAL SCOUR AT ABUTMENTS . . , , .
COMPUTE LOCAL SCOUR AT PIERS . . .
PLOT TOTAL SCOUR DEPTHS AND EVALUATE DESIGN
SCOUR EXAMPLE PROBLEMS , . , , . . .

EVALUATING THE VULNERABILITY OF EXISTING BRIDGES
INTRODUCTION . . . , , . . . . . , .
THE EVALUATION PROCESS , , , . . . .
CONDUCTING SCOUR EVALUATION STUDIES
DOCUMENTING BRIDGE SCOUR ASSESSMENTS

INSPECTION OF BRIDGES FOR SCOUR
INTRODUCTION , . .
OFFICE REVIEW . . .
BRIDGE INSPECTION
UNDERWATER INSPECTIONS
NOTIFICATION PROCEDURES

i

1
1
1
1
2
AT
2
7
7
7
8
10
15
18
20
23
23
24
28
31
31
31
31
31
33
34
35
45
48
57
60
75
75
76
79
81
83
83
84
84
90
90