HY8:Increased Resistance in Culverts

Increased Resistance in Box Culverts

The input variables required for this calculation are the following:

h/r_i—Ratio of roughness element height divided by hydraulic radius taken about the top of the roughness element.
Height of the roughened section (h)

The input variables required for this calculation is the following:

L/D_i — Ratio of roughness element spacing divided by the diameter of the culvert opening at the roughness element. (Range = .05 to 1.5)
h/D_i — Ratio of roughness element height divided by the diameter of the culvert opening at the roughness element. (Range = .005 to .1).
L_r/P_i — Ratio of the roughness length to inside perimeter (Range = 0.0 to 1.0)
Diameter of roughened section (Opening, D_i)

The following figure shows the flow regimes and variables for an increased resistance energy dissipator implemented in a circular culvert.

Variables from the figure

L — Length from beginning of one roughness element to the beginning of the next roughness element.
h — height of roughness element
D_i — diameter of roughened section (opening)

v • e HY-8
Introduction:	Getting Started • Layout • Vena Contracta • Building a Project • Locate Project • Culvert Crossing Data • Run Analysis • Report Generation
Crossing and Culvert Data:	Crossings • Discharge Data • Roadway Data • Tailwater Data • Irregular Channel • Culvert Data • Site Data • Culvert Invert Data • Embankment Toe Data
Analysis	Project Units • Roadway Overtopping • Inlet Control Computations • Outlet Control Computations • Tables and Plots
Energy Dissipation	Scour Hole Geometry • Increased Resistance • Tumbling Flow • USBR Type IX Baffled Apron • Drop Structures • Stilling Basins • Streambed Level Structures
Methods	Aquatic Organism Passage • Low Flow Hydraulics
Troubleshooting	Differences from DOS HY-8 • Limitations • HY-8 User Manual