Maintaining Mainline Pitch thru Culverts

[TapTapTap]

I've been challenged by my driveway crossings through culverts. Right now I run through a total of 4 and 2 freeze up. The problem is simply that the line tends to sag inside of the culvert and sags are particularly bad where the sun doesn't shine on the line. It doesn't help that the culverts aren't pitched very much so there is very little tolerance. And, it's hard to connect the line to the wire and for the ties to stay put as the mainline is installed.

Does anyone have any tricks to share?

[toothfairy050]

I ran high tensile wire through my culvert and then wire tied mainline to wire every 18 inches inside the culvert.

[TapTapTap]

I ran high tensile wire through my culvert and then wire tied mainline to wire every 18 inches inside the culvert.

That's what I would have done if the culverts were large enough to enter into.

[christopherh]

Can you run the mainline through schedule 40 or some rigid drain pipe to keep it from sagging?

[TapTapTap]

Can you run the mainline through schedule 40 or some rigid drain pipe to keep it from sagging?

I've thought about that a lot and I believe that could work ok in a relatively short culvert, particularly if there is room for plenty of pitch. But my culverts are 20 or more feet long, and at that length a sleeve is not stiff enough to prevent a sag. Also, the heavier you make the sleeve the more deflection you create on the wire. And, a larger diameter sleeve (stiffer with less sag) would allow the mainline to wiggle into smaller sags.

[collinsmapleman2012]

can you undo one end, tie it every foot (or even 6 inches) and get it reset? Probably would help to have a tensioner and a tension grip close to one end of the culvert, so its at its stiffest point.

[DrTimPerkins]

+1 on the previous suggestion. This is how we've done several culvert passages -- prearrange them on wire and ties and then pull them through. They still can freeze up some if there is insufficient pitch. We've set them up with quick connects so we can swap from one line to another if need be, or disconnect and try pumping hot water through them. The main thing is to get the sags and dips out and make sure the pitch is good enough.

[MapleCamp]

I have a 6 inch culvert under a sled trail, its corrugated poly pipe that I ripped down the middle with a chain saw that I am able to slide on once its wire tied. I like the Doctors advice on quick connects that I have been playing with for a couple of years now

[TapTapTap]

I have a 6 inch culvert under a sled trail, its corrugated poly pipe that I ripped down the middle with a chain saw that I am able to slide on once its wire tied.

Very creative idea if I understand it correctly. It sounds like you: dig a trench to the culvert subgrade profile, install the wire and mainline with ties, longitudinally split the culvert open with a single cut, put the split culvert over the wire and mainline, and backfill the culvert. Is that your process? Do you repair the culvert to preserve its structural integrity?

[MapleCamp]

Very creative idea if I understand it correctly. It sounds like you: dig a trench to the culvert subgrade profile, install the wire and mainline with ties, longitudinally split the culvert open with a single cut, put the split culvert over the wire and mainline, and backfill the culvert. Is that your process? Do you repair the culvert to preserve its structural integrity?
I did it on a high spot on the main line run, I did not repair the rip cut , and I did not fill the trench, I covererd it with planks and pack it down as the snow falls. In summer we ride over the planks.

[TapTapTap]

Thanks for the help everyone. I hope that this was a useful topic. I know it was helpful for me and now have some fresh ideas to work with.

[TapTapTap]

Update from today:

Based on thinking inspired by responses the my post, I went out today and did the following:

- Excavated around the fairly shallow 6" PVC pipe on one of my crossings.
- Slid it over the mainline and away from the crossing area.
- Tied wire to PE mainline at 12 to 15" on center
- Slid the pipe back to the crossing area.
- Made some additional profile adjustments to best fit the wire.
- Backfilled the pipe.

Obviously the shallow small diameter pipe (not even a water-bearing culvert) made it reasonably simple - with a small excavator. But it could be done on a larger scale and it demonstrates a good method for a new culvert installation.

This takes care of one of my challenging culverts and sets me up with a process for some expansion work planned for the coming season. The remaining problem culvert is not solvable since it is located on the lower side of a sap ladder so it will never drain - sag or not.

[DrTimPerkins]

Good luck Ken....you'll know better next spring. Culverts can be a real pesky problem that can take a while to solve (if ever).