Area of RCP Arch Pipe
Area of RCP Arch Pipe
(OP)
I need help. I have a table for arch pipe to round equivalent pipes.What i need is a formula for the area of the arch pipe.
Richard A. Cornelius, P.E.
WWW.amlinereast.com





RE: Area of RCP Arch Pipe
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RE: Area of RCP Arch Pipe
Richard A. Cornelius, P.E.
WWW.amlinereast.com
RE: Area of RCP Arch Pipe
RE: Area of RCP Arch Pipe
RE: Area of RCP Arch Pipe
RE: Area of RCP Arch Pipe
A 73" span x 45" rise RCP arch has a waterway area of 17.7 sq. ft. and is "equivalent" to a 60" circular pipe which has a waterway area of 19.6 sq. ft. In other words, it is just a close match.
good luck
RE: Area of RCP Arch Pipe
RE: Area of RCP Arch Pipe
A 60" pipe flowing full would carry about 90 cfs at a slope of 0.001 ( n= .013) (page 182)
A 45" x 73" pipe arch at the same slope and "n" carries about 72 cfs ( page 194).
A 60" pipe
maximum capacity is about 1.08*90 cfs = 97 cfs
I do not know, but it seems probable that an arch pipe would have similar characteristics as a circular pipe for flows at or near full because the top inside of the pipe is, in fact, a circular arc. If that is so we might expect the arch pipe to carry about 1.08 * 72 cfs = 78 cfs when flowing between 0.80 and 0.90 full.
For practical purposes this may be close enough but, the difference seems to be plus or minus 25%.
RE: Area of RCP Arch Pipe