Pipe Culvert at Small Ditch at End of Residential Driveway
Pipe Culvert at Small Ditch at End of Residential Driveway
(OP)
I am working on a project where a homeowner is installing a concrete driveway over a very small (~12" deep x 5' wide) ditch. The ditch runs around a cul-de-sac, between the asphalt paving and sidewalk and tapers up to each one. The remaining driveways currently have 6" corrugated plastic piping running through/below them. The portion of driveway I am working on is only between the sidewalk and asphalt paving. He will be incorporating the sidewalk as part of his driveway (or this is probably a bad idea too?)
As it sits, the top of the plastic pipe looks to be about 6" below the top of the driveways. At this rate, I am fairly confident I just need to cast the pipe into the concrete driveway - would you guys agree? There just isn't any room to get appropriate cover for the subgrade and subsequent drive.
So if that is the case, I am thinking to excavate 24" below the bottom of the ditch to get down below frost depth - this puts us at 36" below final driveway elevation. So then 12" compacted fill followed by a 24" block of concrete with the 6" pipe cast in to serve as the driveway.
It's obviously a lot of concrete, but it's only about 5-6' wide and I don't see how to get a suitable base layer for the driveway, considering the 6" pipe is so close to grade.
Thoughts?
As it sits, the top of the plastic pipe looks to be about 6" below the top of the driveways. At this rate, I am fairly confident I just need to cast the pipe into the concrete driveway - would you guys agree? There just isn't any room to get appropriate cover for the subgrade and subsequent drive.
So if that is the case, I am thinking to excavate 24" below the bottom of the ditch to get down below frost depth - this puts us at 36" below final driveway elevation. So then 12" compacted fill followed by a 24" block of concrete with the 6" pipe cast in to serve as the driveway.
It's obviously a lot of concrete, but it's only about 5-6' wide and I don't see how to get a suitable base layer for the driveway, considering the 6" pipe is so close to grade.
Thoughts?





RE: Pipe Culvert at Small Ditch at End of Residential Driveway
otherwise, just overexcavate and remove the organics and silt, replace with good structural backfill. I dont see much reason for a 6 inch pipe. that will have approximately zero capacity and once it gets silted up, it will be useless. A trench drain might be a better idea, it would have more capacity and could be cleaned easier. or if water is only occasional, a dipped crossing would be a low tech option.
RE: Pipe Culvert at Small Ditch at End of Residential Driveway
RE: Pipe Culvert at Small Ditch at End of Residential Driveway
How much would you overexcavate? 12"?
I'm not sure how I would get a trench drain to work in this situation. Simply because the top of the driveway is only 12" above the bottom of the ditch. Therefore, I'd end up having concrete driveway, then a full height trench drain, then more concrete driveway. There's nothing really tying it all together at that point. I'm trying to get water from the ditch on one side of the driveway to the ditch on the other
RE: Pipe Culvert at Small Ditch at End of Residential Driveway
Given the cover issue cited, rather than using 6" corrugated plastic, I would either use 6" ductile iron pipe or use a 12" RCP set 6" deeper. (Allowing the 12" to become half filled with soil will still have better capacity and strength than the 6" plastic.)
RE: Pipe Culvert at Small Ditch at End of Residential Driveway
RE: Pipe Culvert at Small Ditch at End of Residential Driveway
RE: Pipe Culvert at Small Ditch at End of Residential Driveway
RE: Pipe Culvert at Small Ditch at End of Residential Driveway
RE: Pipe Culvert at Small Ditch at End of Residential Driveway
Look at page 10
http://www.eng.auburn.edu/files/centers/hrc/930-59...