Culvert needing reinforcement

RalphVa · Apr 16, 2005

I moved some gravel down to my little stream, about 5' wide and about 2" deep. Put gravel on top of 5 PVC pipes 4" by 6' laid side by side with maybe a couple inches between each. Water is flowing nicely about 1/3 way up on each pipe.

Figured 6' would be wide enough, as my 4010 is only 48" wide. However, I'm having a little bit of trouble with side giveaway. The gravel depth is maybe 18".

Wonder what I can reinforce it with? Thinking maybe just putting a 5' by 6' subway grate down on top the gravel (5' width with long side across stream). Wonder if sifting some concrete or putting asphalt patch material along the sides would help? Maybe 4x4s placed along the side, kinda imbedded into the gravel?

Ralph

pat32rf · Apr 16, 2005

If you have gravel piled 18" high, you can figure thaqt under the BEST conditions it will only hold a 45% slope, without any vibration from traffic or water runoff. This means that your culverts are too short, unless you live in a warm dry area( no rain to wash them out) and can either coat the sides with either THICK vegetation or something like concrete(forget this if you get frost) Your best bet is to extend the ends of the pipes by a couple of feet, More is better. especially on the upstream side. We often use "Big O" for this and run it 4-6' upstream so we can lift it to clean out the leaves before they plug the culverts. Pat

ScottAR · Apr 17, 2005

It's a little on the ugly side but bags of sakrete laid like bricks with rebar "nailing" the bags to the ground works pretty well up to 2-3 feet tall. Some farm culverts are done like this.

The paper bags eventually disappear leaving concrete "bricks."

Dachshund · Apr 17, 2005

When I worked for the State of Kansas, we used to do this on bridge projects. After about 2 years the bags would disolve and ther would be concrete "pillows" left for rip-rap. BE SURE TO ANCHOR THEM INTO SOLID GROUND! Best thing to do is to widen the tube AND use the concrete bags. You really only have to widen it in one direction, just move the road bed over in that direction.

Egon · Apr 17, 2005

As mentioned the culverts need extension so you can obtain the proper road surface width. If the gravel isn't crushed the slope will have to be lower.

Egon

RalphVa · Apr 18, 2005

I've bought some couplers and have added 6" of pipe to put onto each side. Also bought 4 bags of concrete/gravel mix. Think I'll just clear out the gravel above the pipes and lay the bags on top the pipes and extensions with gravel on top the bags after I cut away about 90% of the bag on top. This will kinda disguise the the bags to those with an artist's eye. After I finish, I'll pour some water over the gravel to go into the bags.

The bridge is only about a foot tall. My 6' pipes would work, but with no margin of safety on my 4' wide tractor. Prefer not to drink the stuff or get stuck in it.

Ralph

LBrown59 · Apr 22, 2005

You could build an abutment for each end of the drain pipe out of 2x4s and plywood.

Use treated if you want to leave it or non treaded if you want to fill in against it with dirt or concrete and later remove the abutments .

Another thing you could do is lay heavy pieces of busted up concrete on top of the gravel going from the bottom of the stream to the top off the fill over the drain pipes.

I got just what you need stacked at the bottom of my driveway with a sign on it that says FREE CONCRETE CHUNKS. l.o.l.