I need to install a culvert at the entrance of my new lot. Only constraint I am given is 15" min ID. Going with dual wall corrugated plastic. Due to the angle, pitch, etc. of the existing ditch and surrounding ground, it will only have about 3" of fill on top (not the standard 12"). To install it with 12" coverage would create a sort of mound to drive over. Has anyone here actually installed a 15" ID dual wall culvert with only a few inches of fill on top and had construction vehicles (well drilling rig, dump trucks with bulldozer trailers, ect.) drive over it? Hoping to find someone who has real world experience with this and not speculation based on internet searches. Thanks!
Minimum Culvert Depth
- Thread starter Ben333
- Start date
PopcornSutton
Well-known member
The lay of the land on either side will dictate where the pipe needs to be. You don;t want your pipe a low spot. I've seen culvert pipes almost bare on top. If you can get 3" of coverage, I would go with it, unless you expect heavier traffic than normal vehicles.
That's why they make elliptical pipe, interior capacity but much shallower.
That's why they make elliptical pipe, interior capacity but much shallower.
dcg9381
Well-known member
Plastic ones? You can get steel ones in 14 gauge, which is what I used for a "low coverage" spot like this. No experience with plastic though.
PopcornSutton
Well-known member
No, it was corrugated steel.
mike93lx
ALLIANCE MEMBER
How about two smaller culverts? If the 15" diameter important or the cross sectional area?
Two 12" culverts will flow more than a single 15"
Two 12" culverts will flow more than a single 15"
jblnut
ALLIANCE MEMBER
There are multiple different grades of plastic pipe. Some will collapse with the loads listed below and others will hold up better when installed improperly. What type of pipe or where were you going to get it ?
I have installed ADS HP Storm Dual Wall pipe in a bunch of places and it's really great stuff. The "regular" black dual wall plastic stuff isn't nearly as tough/durable/whatever you want to call it.
HP Pipe | Stormwater Management Solutions| Advanced Drainage Systems
Discover cutting-edge water management solutions with HP Storm Dual Wall Pipe, tailored to meet diverse drainage challenges.
www.adspipe.com
I installed a temp 12" dual wall ADS N-12 pipe as a culvert with 4" (roughly) of top fill that was properly compacted like it was supposed to be during installation and it made a morning of 12yd loaded trucks going over it before it gave up and caved in. If I had to guess I'd say around 40 trucks went over it loaded and back unloaded before I had to dig it out and fill the trench with dirt so the trucks could keep going.
A safe rule of thumb to follow is to have an absolute minimum of half the diameter of the pipe in fill above the pipe.
You may get away with it but someone will drop into it eventually. If it's passenger cars/trucks and smaller it'll likely be fine for a long time.
A lot of great advice here. I am aware properly packing the backfill layers will provide more strength, in that light, has anyone tried back filling with cement? Something simple like post setting cement, that would really shore things up, but I guess a heavy load would still punch through the top.
Been looking for steel culvert, hard to find anyone nearby who sells it without special ordering it in
Been looking for steel culvert, hard to find anyone nearby who sells it without special ordering it in
Dagny
Well-known member
The farmers here say cover the same as diameter .
I was thinking ADS's N-12 dual wall culvert, it is HDPEThere are multiple different grades of plastic pipe. Some will collapse with the loads listed below and others will hold up better when installed improperly. What type of pipe or where were you going to get it ?
I have installed ADS HP Storm Dual Wall pipe in a bunch of places and it's really great stuff. The "regular" black dual wall plastic stuff isn't nearly as tough/durable/whatever you want to call it.
HP Pipe | Stormwater Management Solutions| Advanced Drainage Systems
Discover cutting-edge water management solutions with HP Storm Dual Wall Pipe, tailored to meet diverse drainage challenges.
I installed a temp 12" dual wall ADS N-12 pipe as a culvert with 4" (roughly) of top fill that was properly compacted like it was supposed to be during installation and it made a morning of 12yd loaded trucks going over it before it gave up and caved in. If I had to guess I'd say around 40 trucks went over it loaded and back unloaded before I had to dig it out and fill the trench with dirt so the trucks could keep going.
A safe rule of thumb to follow is to have an absolute minimum of half the diameter of the pipe in fill above the pipe.
You may get away with it but someone will drop into it eventually. If it's passenger cars/trucks and smaller it'll likely be fine for a long time.
coldh2o
Well-known member
Pipe manufacturer will provide the strength and minimum cover requirements.
Does this install have to be permeant? In other words can you put something in that is temporary till the heavy work is done and then go back and put in what the county wants. Can you get ahold of some heavy timbers or steel plate to bridge across the culvert during the building process? Ask the well driller or cement company if they have something to spread the load when accessing your property. Pictures and location might help. Makes some difference if you are in snow and freezing weather doing this or the sunny south.
lg
no neat sig line
lg
no neat sig line
Firebrick43
Well-known member
You could pour proper concrete around it and with proper reinforcement and 5" of concrete over the top it would survive most any traffic.
Steel culvert is going to be probably cheaper however. Plastic culvert at a shallow depth is an accident waiting to happen.
When do you need to install this culvert? A bulldozer and well drilling rig won't need a culvert to get on to your lot. My inclination would be to make the ditch passable for the necessary traffic for now and install whatever culvert is needed after the heavy traffic has passed.
How much water does this ditch actually carry? The culvert needs to have a 15" cross sectional area, but does anything say the bottom of that culvert needs to be flush with the bottom of the ditch? You could just install it 5" low. The bottom will fill up quickly and then what's left will work just fine. If whomever is required to sign off on the install disapproves, I'd probably go with concrete. 3" of cover might work for passenger vehicle traffic, but it won't survive much abuse.
How much water does this ditch actually carry? The culvert needs to have a 15" cross sectional area, but does anything say the bottom of that culvert needs to be flush with the bottom of the ditch? You could just install it 5" low. The bottom will fill up quickly and then what's left will work just fine. If whomever is required to sign off on the install disapproves, I'd probably go with concrete. 3" of cover might work for passenger vehicle traffic, but it won't survive much abuse.
New plastic drain is costly especially big sizes ,I d look in FB/MP for some dug up heavy wall drainpipe ,either concrete or steel ,and use that....steel can have trucks driving over exposed top ...........sure it will rust out in 30 or 40 years
Eric S.
Active member
I belive the number is 1/2 of pipe diameter. So your 15" pipe should have 7.5" of cover minimum.
Bill T
Well-known member
Thank you, great idea. I could 'mound' it up and then remove it later
That is good. I am not familiar with well digging rigs and their ground clearance. My little midsize pickup crosses the ditch with little problem as long as have it in 4WD. A car won't make it at all. But this is good stuff, if I can make with my truck I am sure a well drilling rig can with no problem at all - probably sounds dumb that I didn't think about that, but I don't do this stuff every day.
I think that is my answer: Put in the culvert, cover it the best I can, it will be fine for residential use. Well rig and others by pass culver and drive through the ditch. I'll cut a temp road in for them and let it grow shut when done.
captaindiode
Well-known member
In North Carolina, the DOT will install a driveway culvert in the right of way if the homeowner purchases the pipe. Might be worth checking with your local department of transportation.