FLOOD08704

• County: Statewide
• Basin: Statewide
• Title: Hydraulics of Bridge Waterways
• Date: 3/1/1978
• Prepared For: US
• Prepared By: USDOT
• Floodplain - Doc Type: Educational/Technical/Reference Information

CHAPTER XL-Preliminary Field and
Design Procedures

11.1 Evaluation of flood hazards__________ 59
11.2 Site study outlineh_________________ 59
11,3 Hydrological analysis outline__ __ __ __ _ 60
11.4 Flood magnitude and frequency _ __ _ __ 60
11.5 Stage-discharge_____________________ 61
11.6 Channel roughness__________________ 61
11.7 Bridge backwater design procedure___ _ 61

Chapter XII,-lliustrative Examples

12,1 Example I-Normal crossing____ __ _ __
12,2 Example 2- Dual bridges___ _ _ _ _ _ _ _ _ _
12,3 Example 3-Bkewed crossing__ _ _ _ _ ,_ _
12.4 Example 4-Eccentric crossing_ _ __ _ __
12,5 Example 5-Abnormal stage-discharge
12,6 Example 6-Backwater with scour _ _ __
12.7 Example 7-Upstream girder in flow __
12,8 Example 8-Superstructure partially
inundated_______________________
12,9 Example 9-Flow over roadway em-
bankrnent_______________________
12,10 Example lo-Design of a spur dike_ ___
12.11 Example 11-Bridge backwater with
supercritical flow _ __ _ . __ _ _ __ . _ _ __ _

Page

Page

Chapter XIIL-Discussion of Procedures and
Limitations of Method

13,1 Review of design methods __ __ _ __ h __ 87
13,2 Further research reconnnended_ __ _ __ _ 89

Selected Bibliography_____. ____ ____._ ____ _ 91

Appendix A,-Development of Expressions
for Bridge Backwater

65
68
69
71
75
77
80

A,l-Type I flow (subcritical)__.______ 95
A.2-Type II flow (water surface passes
through critical depth) _ . _ _ _ __ _ 98
A,3-Type III flow (supercritica1)______ 100

Appendix B.-Basis of Revisions

82

B,I-Backwater coefficient base curves__ 101
B,2-Distance to maximum backwater
curves_______________________ 102
B,3-Velocity head correction factor (a,) 103
B,4-Dual bridges.___________________ 104

82
83

84

Appendix C,-Development of chart for de-
termining length of spur dikes 109

vi