1.7.9 Chapter 10 - Overview Examples of Design for Highways in the River Environment
The objective of Chapter 10 is to present overview examples of the use of the principles
presented in this manual in the design of highway encroachments and crossings in the river
environment. A three-level design procedure is emphasized in these designs. The designs
use the geomorphic, hydrologic, hydraulic, and river mechanics principles described in this
manual to design safe and economical crossings that protect, maintain and restore the river
environment.
Three examples are given to illustrate the application of the principles, methods, and
concepts given in this manual. In the examples, the designs are determined by well-
established numerical procedures; however, they also depend heavily on the judgment of the
engineer.
1.7.10 Chapter 11 - References
Chapter 11 contains an alphabetical listing of the references cited throughout the document.
1.7.11 Appendices
The appendices present a discussion of the metric (SI) system (Appendix A), analysis of
additional sediment transport relationships (Appendix B), and an Index (Appendix C).
1.8 DUAL SYSTEM OF UNITS
This manual uses dual units (SI metric and English). In Appendix A, the metric (SI) unit of
measurement is explained. The conversion factors, physical properties of water in SI system
of units, sediment particle size grade scale, and some common equivalent hydraulic units
are also given. This edition uses for the unit of length the meter (m) or foot (ft); of mass the
kilogram (kg) or slug; of weight/force the newton (N) or pound (lb); of pressure the Pascal
2
2
(Pa, N/m ) or (lb/ft ); and of temperature the degree centigrade (C) or Fahrenheit (F). The
unit of time is the same in SI as in English system (seconds, s). Sediment particle size is
given in millimeters (mm), but in calculations the decimal equivalent of millimeters in meters
is used (1 mm = 0.001 m) or for the English system feet (ft). The value of some hydraulic
engineering terms used in the text in SI units and their equivalent English units are given in
Table 1.1.
Table 1.1. Commonly Used Engineering Terms in SI and English Units.
Term
SI Units
English Units
Length
1m
3.28 ft
3
3
Volume
1m
35.31 ft
3
3
Discharge
1 m /s
35.31 ft /s
2
2
Acceleration of Gravity
9.81 m/s
32.2 ft/s
3
3
Unit Weight of Water
9800 N/m
62.4 lb/ft
3
3
Density of Water
1000 kg/m
1.94 slugs/ft
3
3
Density of Quartz
2647 kg/m
5.14 slugs/ft
Specific Gravity of Quartz
2.65
2.65
Specific Gravity of Water
1
1
Temperature
C = 5/9 (F - 32)
F
1.21
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