spread calculation
spread calculation
(OP)
I'd like to know how to do the spread calculation.
I found the station of each inlet, then I calculate the overland runoff, at last the spread should be calculated. but how?
I found the station of each inlet, then I calculate the overland runoff, at last the spread should be calculated. but how?





RE: spread calculation
RE: spread calculation
RE: spread calculation
RE: spread calculation
ht
Good Luck!
RE: spread calculation
You can find a similar shaped grate from a different manufacturer and use their equation. cvg picked up some of the aspects I missed; manning's n also features into it.
RE: spread calculation
good luck
RE: spread calculation
RE: spread calculation
In 47 years, I've never been asked to make such a calculation. Considering that flows calculated by the Rational Method, or any other method, are estimates of probabilities ( + or- 50% at best ?) and considering that most vehicles ( except tricycles ) can probably drive through 6 inches to a foot of water without encountering great difficulty, seems like a great waste of time.
Thanks for the information nevertheless.
good luck
RE: spread calculation
RE: spread calculation
RE: spread calculation
RE: spread calculation
While a vehicle 'can' drive through 6" of water; would you want to be traveling on wet pavement with no standing water...and then hit a spot of 3" depth while traveling at 30mph?
For a 2000 ft. street length...is a pair of basins at the sump sufficient? An extra pair either side of the sump? Is a pair every 200 ft. overkill? (this all depends on road cross slope and longitudinal slope and inlet efficiency of course).
While estimates of flow have margins of error, one can at least establish a standard for attempting to have a design which is mindful of safety with economy in mind as well.
RE: spread calculation
I live in the Charlotte, NC area, and every municipality surrounding charlotte requires it. Of course, they all use the same standardized inlets, so they provide the formulas to use and the rainfall intensity to evaluate it for.
It's not hard- you just set up the spreadsheet and start 'plugging and chugging', but it's a major hassle.
Sounds like other parts of the country are much luckier.
RE: spread calculation
FHWA's HEC22 describes the capture analysis for inlets on-grade. Just follow the link I provied above to get to the website.