Dual Wall HDPE Culvert vs Metal?

[s219]

I have a 15" dual wall HDPE culvert pipe on our driveway. During construction it had about 9" cover and we had multiple cement trucks pass over it. Later when I finished the driveway I went to about 12" cover. Never noticed any issues at all. I am a big fan of this type of pipe, and have used it in other places.

 

[PineBrookFarm]

i've got a hand full of 12" double wall HPDE culverts that have had regular traffic from loaded concrete trucks and tri-axle dump trucks that are less than 18" deep. I shoot for 12" of good granular fill material over the culvert. As long as the material drains well and doesn't get muddy you will be fine with 8-12" of well compacted gravel.

 

[Mainahs70]

I had a 15" double wall installed on my driveway with about 6" or less crushed 3/4 gravel put above it. After multiple concrete trucks and probably 100 or so loaded wheelers in the past 10 months it has failed in a few spots. I have a 12" coming tommorrow that I will put in a foot deeper to give me close to 18" of fill above it. That and no more heavy trucks and I shouldn't have any issues.

 

[boomer1025]

Lay the pipe and cover, then make a bridge with railroad ties over the pipe. Taper the ends of the ties and add some fill at the end. You would only need 6 ties that are spaced for the wheel tracks on the trucks.

 

[Fallon]

The more compacted (undisturbed is best) the earth is along the sides of the pipe and the tighter the pipe fits against the sides determines how much the pipe can deflect from weight pushing down on the top...

i.e., dig the ditch just wide enough to get the pipe in...

If you make it a tight fit for the pipe, you cant tamp backfill under & completely around the pipe. With voids under the pipe, it will lack support & crush much more easily. Properly compacted backfill all around the pipe is key for strength.

 

[RedNeckRacin]

Fallon nailed it. Proper compaction not a skinny ditch is the key to pipe life. The lower haunches of the pipe are critical for the pipe support to handle the loads that it is rated for. You MUST compact the material in lifts that can be adequately compacted to near 100% standard proctor density. Failure to do this means the pipe isn't supported and can't shed load to the soil. If you want to follow the penndot guidelines it's the pipe diameter plus 4 feet. I think that's a bit much for a 15" pipe but they sometimes shoot for a 100yr service life.

 

[LouNY]

The hard part about compacting on the lower half of a culvert (which is the most critical) is keeping the culvert from lifting as you are compacting.
I usually set the bucket down on the top of the culvert as I'm tamping the backfill down. Kind of a pain in the butt but otherwise I can't get the needed and desired compaction.

 

[/pine]

FYI...Depending on the soil type undisturbed earth is generally much denser than material compacted with vehicle tires or a loader/hoe bucket etc...

 

[BertZegers]

Lay the pipe and cover, then make a bridge with railroad ties over the pipe. Taper the ends of the ties and add some fill at the end. You would only need 6 ties that are spaced for the wheel tracks on the trucks.

Even using some sheets of steel during the time of heavy traffic, would be beneficial. Excavating companies use them for crossing soft spots or for temporarily roads. Ask the contractors that will work on your property if they own some.

 

[smiley]

Put in HDPE. It will be good with your plans for normal driveway traffic. If you are worried about heavy traffic for a short time or one time drive then you could build up over the culvert with a "bump" to distribute some of the load and then after.

View attachment 613471

Either a bump or some planks. I crossed many 2-3 day old green sidewalks with both methods with some really big equipment. The greener the sidewalk the more fill or planks.
Here is a site that pretty much answers the queustions.
https://www.prinsco.com/wp-content/...aximum-Burial-Depth-per-AASHTO-Tech-Note3.pdf
Smiley