HY8:Box Inlet Drop Structure: Difference between revisions

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The input variables required for this calculation is the following:
The input variables required for this calculation is the following:


* H<sub>D</sub> -- Desired drop height. Must be between 2 and 12 ft or between 0.6 and 3.7 m.
* H<sub>D</sub> &mdash; Desired drop height. Must be between 2 and 12 ft or between 0.6 and 3.7 m.
* New Slope  -- The slope that will exist on the channel once the drop structures are in place (The new slope must be subcritical).
* New Slope  &mdash; The slope that will exist on the channel once the drop structures are in place (The new slope must be subcritical).
* Box Length -- Length of box inlet. (USER'S CHOICE)
* Box Length &mdash; Length of box inlet. (USER'S CHOICE)
* W<sub>2</sub> -- Width of box inlet.  Must fit criteria (.25 < H<sub>D</sub>/W<sub>2</sub> < 1)
* W<sub>2</sub> &mdash; Width of box inlet.  Must fit criteria (.25 < H<sub>D</sub>/W<sub>2</sub> < 1)
* W<sub>3</sub> -- Width of the Downstream End of Stilling Basin. This must be equal to or larger than the culvert width.  
* W<sub>3</sub> &mdash; Width of the Downstream End of Stilling Basin. This must be equal to or larger than the culvert width.  
 
*Flare of Stilling Basin (1 Lateral: Z long) &mdash; This value must be greater than or equal to 2, which is to say 1 lateral: 2 Long)
Flare of Stilling Basin (1 Lateral: Z long) -- This value must be greater than or equal to 2, which is to say 1 lateral: 2 Long)
*Length from Toe of Dike to Box Inlet &mdash; If a dike is used, the distance from the toe of the dike to the box inlet must be entered.  If no dike is used, enter a value of 100 ft or 30.48 m for this distance.
 
Length from Toe of Dike to Box Inlet -- If a dike is used, the distance from the toe of the dike to the box inlet must be entered.  If no dike is used, enter a value of 100 ft or 30.48 m for this distance.
 


The following figure shows a plan and side view of a box inlet drop structure.
The following figure shows a plan and side view of a box inlet drop structure.
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Variables from the figure
Variables from the figure


* W<sub>1</sub> -- Width of the upstream end of the basin
* W<sub>1</sub> &mdash; Width of the upstream end of the basin
* W<sub>2</sub> -- Width of box inlet crest
* W<sub>2</sub> &mdash; Width of box inlet crest
* W<sub>3</sub> -- Width of the downstream end of the basin
* W<sub>3</sub> &mdash; Width of the downstream end of the basin
* W<sub>4</sub> -- Distance from the toe of dike to the box inlet
* W<sub>4</sub> &mdash; Distance from the toe of dike to the box inlet
* L<sub>1</sub> -- Length of box inlet
* L<sub>1</sub> &mdash; Length of box inlet
* L<sub>2</sub> -- Minimum length for the straight section
* L<sub>2</sub> &mdash; Minimum length for the straight section
* L<sub>3</sub> -- Minimum length for final section (potentially flared)
* L<sub>3</sub> &mdash; Minimum length for final section (potentially flared)
* H<sub>0</sub> -- Drop from crest to stilling basin floor
* H<sub>0</sub> &mdash; Drop from crest to stilling basin floor
* h<sub>2</sub> -- Vertical distance of the tailwater below the crest
* h<sub>2</sub> &mdash; Vertical distance of the tailwater below the crest
* h<sub>3</sub> -- Height of the end sill
* h<sub>3</sub> &mdash; Height of the end sill
* y<sub>0</sub> -- Required head on the weir crest to pass the design flow
* y<sub>0</sub> &mdash; Required head on the weir crest to pass the design flow
* y<sub>3</sub> -- Tailwater depth above the floor of the stilling basin
* y<sub>3</sub> &mdash; Tailwater depth above the floor of the stilling basin
* h<sub>4</sub> -- Sill height
* h<sub>4</sub> &mdash; Sill height




{{HY8Main}}
{{HY8Main}}
[[Category:Energy Dissipators|B]]

Latest revision as of 14:48, 10 October 2016

The input variables required for this calculation is the following:

  • HD — Desired drop height. Must be between 2 and 12 ft or between 0.6 and 3.7 m.
  • New Slope — The slope that will exist on the channel once the drop structures are in place (The new slope must be subcritical).
  • Box Length — Length of box inlet. (USER'S CHOICE)
  • W2 — Width of box inlet. Must fit criteria (.25 < HD/W2 < 1)
  • W3 — Width of the Downstream End of Stilling Basin. This must be equal to or larger than the culvert width.
  • Flare of Stilling Basin (1 Lateral: Z long) — This value must be greater than or equal to 2, which is to say 1 lateral: 2 Long)
  • Length from Toe of Dike to Box Inlet — If a dike is used, the distance from the toe of the dike to the box inlet must be entered. If no dike is used, enter a value of 100 ft or 30.48 m for this distance.

The following figure shows a plan and side view of a box inlet drop structure.

HY8fig114BoxDrop.png

Variables from the figure

  • W1 — Width of the upstream end of the basin
  • W2 — Width of box inlet crest
  • W3 — Width of the downstream end of the basin
  • W4 — Distance from the toe of dike to the box inlet
  • L1 — Length of box inlet
  • L2 — Minimum length for the straight section
  • L3 — Minimum length for final section (potentially flared)
  • H0 — Drop from crest to stilling basin floor
  • h2 — Vertical distance of the tailwater below the crest
  • h3 — Height of the end sill
  • y0 — Required head on the weir crest to pass the design flow
  • y3 — Tailwater depth above the floor of the stilling basin
  • h4 — Sill height