Hydraulic Design of Highway Culverts - DOT On-Line Publications

d. Example Problem #2 (English Units). From example problem no. 4, Chapter III, an existing 7
ft by 7 ft concrete box culvert was originally designed for a 50-year flood of 600 ft³/s and an ELhd
of 114 ft. Upstream development has increased the 50-year runoff to 1,000 ft³/s.
Given:
Inlet Invert Elevation: 100 ft
Existing Entrance Condition: Square edge
Barrel Slope (S): 5 percent
Roadway Centerline Elevation: 115.5 ft
Culvert Length: 200 ft
Flow, ft 3 /s T.W. (ft)
800
1,000
1,200
3.8
4.1
4.5
Requirements: In order to save the existing culvert barrel, design a new side-tapered inlet that
will pass the new 50-year runoff of 1,000 ft 3 /S at the original ELhd of 114.0 ft. The side-tapered
inlet will be constructed upstream of the existing barrel. Prepare outlet control, throat control,
and face control performance for the new inlet.
Note: Charts 14B, 15B, 57B, and 58B, are used in this solution.
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