"Notching" TOP of RCP SD Pipe 2

[GLeiper]

I am looking to notch the top of a 54" RCP (when the pipe is cast) storm drain pipe to allow an existing sanitary sewer pipe to cross over the top of it. Anybody have any suggestions regarding this?

 

[cvg]

on a recent project we solved this problem differently by constructing a "conflict structure". Basically a cast in place structure which allows the sewerline to cross without impacting the the storm drain pipe. See attached file. Unless you know exactly what the elevation, size and location of the existing sewerline is it will be difficult to get your notch to match up with the sewerline and may have to be field fit to work.

 

[pittsig]

We've essentially done what cvg has suggested in several cases where there has been a conflict and not a feasible or economical alternative. The structure could be cast in place, or brick/block and mortar.

You don't mention the type of material of sanitary sewer pipe. In order to minimize damage to the sanitary sewer from debris in the storm drain line, we would replace the sanitary sewer at the crossing with ductile iron pipe (using more pricey ceramic epoxy interior coating for sanitary sewer rather than standard cement lining) and make sure the length of ductile iron pipe is centered on the horizontal flow line of the storm drain pipe. Having no joint on the sanitary sewer pipe in the conflict structure minimizes the chance of a leak of sewage into the storm drain.

 

[cvg]

I agree regarding the DIP pipe. Ours was VCP and is replaced with 1 section of DIP without joints. In our case, this is a 90inch storm drain and about 20 feet deep. so brick and mortar was ruled out in favor of stronger reinforced concrete.

 

[gbam]

I have encountered this situation a few times. We have done what CVG mentions and I have also transitioned the RCP to HERCP and then back to RCP to accommodate the SS. I have had reviewers comment that they would prefer not exposing storm water to the open sewer line incase of future leaks. In either situation we have always called out for the ss to be replaced with DIP.

Good Luck.