Concept explainers
Whether the given culvert will operate under inlet or outlet control for the given conditions.
Answer to Problem 20P
The given culvert is acceptable and inlet control governs.
Explanation of Solution
Given:
The diameter of concrete circular box is
The angle of inclination of flared walls is
The
The design headwater elevation is
Elevation of stream bed at face of invert is
Tail water depth is
Approximate length of culvert is
Slope of stream is
The value of
The value of
Formula used:
The flow rate per width is given by,
Here,
The required headwater is given by,
Here,
The design headwater depth is given by,
Here,
The formula for fall is given by,
The culvert invert elevation is given by,
The depth from outlet invert to hydraulic line is given by,
Here,
The outlet water elevation is given by,
Here,
The required outlet headwater elevation is given by,
Here,
Calculation:
The flow rate per width is calculated as,
Substitute
Consider Figure 16.17, "Headwater Depth for Concrete Pipe Culverts with Inlet Control" from the book "Traffic and Highway Engineering", for a depth of
The required headwater is calculated as,
Substitute
The design headwater depth is calculated as,
Substitute
The fall is calculated as,
Substitute
The culvert invert elevation is calculated as,
Substitute
The depth from outlet invert to hydraulic line is calculated as,
Substitute
The tail water is not greater so take
The outlet water elevation is calculated as,
Substitute
For circular culvert with
The required outlet headwater elevation is calculated as,
Substitute
The required outlet headwater elevation is less than the design headwater design so the given culvert is acceptable and inlet control governs.
Conclusion:
Therefore, the given culvert is acceptable and the inlet control governs.
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Chapter 16 Solutions
Traffic and Highway Engineering
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- Traffic and Highway EngineeringCivil EngineeringISBN:9781305156241Author:Garber, Nicholas J.Publisher:Cengage Learning