Sanitary sewer pipe thru box culvert?

[RickSewerPipe]

Hello Eng-Tips.com community!

I need to cross-under a four lane state highway to get to the township's gravity sewer main on the other side.
In lieu of pneumatic tunnel boring (expensive) the ideal point of cross-under is at an existing state owned box culvert with a low flow stream running thru it (see pic).
Its a 5ft high x 12ft wide box culvert with a 100 year flood design size.
Is it ever permitted to run a sanitary sewer pipe (2" HDPE forced lateral)thru a box culvert of this type? The 2" pipe would be attached to the ceiling of the culvert.

 

[fel3]

Have you talked to the highway department? It's probably their culvert and they would be the ones to decide if it's allowed.

From an engineering perspective, I can envision putting your 2" HPDE pipe inside of a 4" (?) steel carrier pipe that is securely attached to the roof of the culvert, probably near or in an upper corner.

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"Is it the only lesson of history that mankind is unteachable?"
--Winston S. Churchill

 

[RickSewerPipe]

@FEL3
Thanks for your response!
The township sewer engineer is agreeable to this, but said I would have to get PA STATE approval and permit if they allowed this.
...... and other authorities may also want permissions as well (EPA, etc)

 

[bimr]

What are you running, a gravity sewer or a force main?

What is pneumatic tunnel boring?

Why do you state that HDD is expensive? You can construct this within a week?

 

[RickSewerPipe]

@bimr:

What are you running, a gravity sewer or a force main?

Forced lateral (pumped) ...... with siphonic drain function as a back-up.
This 2" lateral is 450ft long!!
The vertical height differential from starting elevation to end discharge into the township's gravity sanitary sewer is 40ft (25ft is of almost a vertical drop straight down .... the remaining pipe is at 1/4" drop per ft)

What is pneumatic tunnel boring?

an air operated cylinder that punches its way horizontally thru the soil ..... leaving a hole to thread your 2" sewer pipe thru

NOTE: Running this 2" pipe across the ceiling of the colvert allows me to transverse the steam without having to do an inverted loop under the stream bed.