# Retaining Wall over Culvert Pipe...



## NorPlan (Mar 21, 2014)

:help: 7 years ago I had widened our Laneway, the culvert pipe in the ditch entering the property stuck out a good 8 ft on both sides of the existing one lane entrance..One side had more of a slope to it so the retaining wall was short..The otherside , as the ditch has about a 45' angle on both sides and were talking a depth of 5 ft. From the top of the present Retaining Wall to the top of the Culvert Pipe..And the distance from the road to the property is 13 ft..

The problem was Self Inflicted, When I built the Retaining Wall and filling in the space with Crushed Stone..I'd fill in about 2ft. Then used my Son's fat tired jeep to pack down, running back and forth.You guessed it , this pushed the wall out a bit..The existing Wall was built with 6 X 6 Timbers, nailed on top of each other using 8" nails..I also used 10ft. steel fence posts pounded down on the outside of the wall..

Fast forward to today, through time the Timbers have become somewhat Water Logged and with the Hot Summer Sun it has started to split and cave in in spots along the top last year...The Debate is what method should I use to Replace the Existing Wall...Interlocking Stones, Poured Concrete, I even thought of the wire cage idea ( 1'W X 2' X 2' ) Blocks with the steel fence posts pounded down through...Thoughts and Ideas Appreciated, Cheers ...Thanks....


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## Wuzzat? (Mar 21, 2014)

PleasePostAPic.  

Or several from several angles, I can't visualize this setup.


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## nealtw (Mar 21, 2014)

So do you have pipe sticking out now or are you right at the end? and welcome to the site.


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## NorPlan (Mar 21, 2014)

nealtw said:


> So do you have pipe sticking out now or are you right at the end? and welcome to the site.




. @ Wuzzat....Sorry No Pic's....The condition of the Timbers and slight lean has to be addressed is the issue basically....

@ nealtw....I'm right on the edge of the culvert pipe so I'll have to Dig a trench on the inside of the retaining wall.....


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## nealtw (Mar 21, 2014)

What you built should have lasted if done right And would be the cheapest to build again.
You should have dug into the bank on both sides so the timber was supported by a foot of dirt on both sides. 6x6 come as long as 16 ft so one peice across the ditch for most of the them and a few dead mans on the way up (dead man) is a peice going back under the drive way to help anchor the wall. Build the wall with a slight tilt back toward the driveway and use 10" nails HDG. Leave a few holes in the wall with good drain rock so water does not get trapped inside.


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## Wuzzat? (Mar 21, 2014)

The problem with this
http://books.google.com/books?id=XL...=onepage&q="retaining wall" lindeburg&f=false
is that you need to know soil types & whatever and the math can get involved.


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## slownsteady (Mar 22, 2014)

> The Debate is what method should I use to Replace the Existing Wall...Interlocking Stones, Poured Concrete, I even thought of the wire cage idea ( 1'W X 2' X 2' ) Blocks with the steel fence posts pounded down through...Thoughts and Ideas Appreciated, Cheers ...Thanks....



The mason picks concrete, the carpenter picks railroad ties, the plumber picks a longer pipe. What material are you comfortable working with?


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## NorPlan (Mar 22, 2014)

slownsteady said:


> The mason picks concrete, the carpenter picks railroad ties, the plumber picks a longer pipe. What material are you comfortable working with?




:beer:   Good Comeback, Originally as my neighbor has a portable sawmill and I had almost a 1/2 load of topsoil leftover..We traded materials....Yes the wood wasn't treated, it lasted 7 yrs...I'm leaning towards either poured concrete or HD Wire cages filled with pit run (2"Rock)....Have a Cement Plant or Quarry 5 minutes in either direction from our home..We've always been successful at negotiating a terrific price & delivery..It's how labor intensive either is going to be ??..Drainage to will have tobe Considered as well...lol...


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## bud16415 (Mar 22, 2014)

Can you extend the pipe to allow more slope? 


Sent from my iPhone using Home Repair


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## Wuzzat? (Mar 23, 2014)

bud16415 said:


> Can you extend the pipe to allow more slope?
> 
> 
> Sent from my iPhone using Home Repair


And if the slope equals the angle of repose for your soil (around 35 degrees up from the horiz) there will be no pressure on the wall.


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## NorPlan (Mar 24, 2014)

Wuzzat? said:


> And if the slope equals the angle of repose for your soil (around 35 degrees up from the horiz) there will be no pressure on the wall.




:hide:   To allow for Sloping is not necessary...When I widened the Laneway the existing retaining wall stands 4ft. High..The area filled in to widen is entirely Crushed Stone from 2" size down...My idea whether poured concrete or rock filled cages is to anchor whatever with steel fence posts pounded down below the frost line....:2cents:


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## bud16415 (Mar 24, 2014)

Sounds like you have a good plan then. Around here I plow a lot of snow and the drive ways with deep ditches to cross and steep sides to the crossing, people are always misjudging and driving off the sides and getting stuck including the guy doing the plowing on occasion. 

We have a lot of wire baskets with rocks but I don&#8217;t see them used on driveways. Might be because of looks. We use them mostly to control erosion on stream banks. Go with the poured concrete and get the footings down way below the frost depth. 

The angle of repose idea I see you don&#8217;t like.


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## nealtw (Mar 24, 2014)

Wire basket system should work but remember you are building a retaining wall so do your home work. If you were buying a premade concrete unit, it comes complete with a footing that goes back under the driveway about 3 ft. Do your homework.


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## inspectorD (Mar 25, 2014)

But bring it one step further. You dont need to por concrete, you could just glue it together. And these blocks are much thicker than any wall you will pour and eventually lean over. 
Just order the ones you want, and set them on a bed of gravel. They crane them in right off the truck for you.
Done , in an afternoon....:beer:

http://prmconcrete.com/block.htm

Good luck.


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## Wuzzat? (Mar 25, 2014)

inspectorD said:


> But bring it one step further. You dont need to por concrete, you could just glue it together. And these blocks are much thicker than any wall you will pour and eventually lean over.
> Just order the ones you want, and set them on a bed of gravel. They crane them in right off the truck for you.
> Done , in an afternoon....:beer:
> 
> ...


I've seen these blocks everywhere.   As long as we're on the subject, how high can they be stacked before you start worrying about them eventually leaning?


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## inspectorD (Mar 25, 2014)

Wuzzat? said:


> I've seen these blocks everywhere.   As long as we're on the subject, how high can they be stacked before you start worrying about them eventually leaning?



Depends on the soil underneath.. and the drainage behind. But they have been installed up to 30 feet in some areas, they just step them back as they go up the embankment. Some are keyed and some are fastened with glues or mortar.

Depends on the Block,

http://www.earthretaining.com/installers.php


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## bud16415 (Mar 25, 2014)

We have something similar around here but mostly we see what we call mafia blocks stacked up to hold a bank. I have seen them at the ends of drives like the OP needs also. They are made from hot loads returning and extras and are quite inexpensive but a PITA to move around without proper equipment. 

If we get one that&#8217;s around 400 pounds light we kindly decline taking that one.


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## NorPlan (Mar 25, 2014)

inspectorD said:


> Depends on the soil underneath.. and the drainage behind. But they have been installed up to 30 feet in some areas, they just step them back as they go up the embankment.



.  The existing wall is 48 inches Vertical from the top of the Culvert Pipe straight up......You guys are giving me a Reality Check and I Thank a you for that...All very good ideas that are Just Pricing me into Never Never Land...lol...

And Yes Drainage will be a concern because , water does pool at the top edge of the wall...Obviously the Laneway slopes that way so that will have to be addressed as well..I'll have to run some heavy duty PVC piping down and poke through the wall, with a drain cap on the top... Were holding back crushed stone, no earth....

Let Me put this out there..As the existing wall was built using Non Treated Wood..If I Rebuilt the Wall using Pressure Treated would , spraying a sealer on the wood when the wall is up...What would the life span be before it too would show signs of Breaking Down ??    Thanks


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## Wuzzat? (Mar 25, 2014)

NorPlan said:


> What would the life span be before it too would show signs of Breaking Down ??    Thanks


Lifespan = Mean Time Between Failures (MTBF) 
and this info is very hard to get.
From a previous post, if the company says 20 years or longer it's 50-50 that the company will be bankrupt before the term is up.


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## nealtw (Mar 25, 2014)

The treated wood rated for underground and should be good for 30+ years, no sealer needed.
You can tell if it's rated for underground as it will have rows of knife cuts on all four sides to get a deeper treatment and any steel like nails has to be hot dipped galvinized as this stuff with water will eat steel in no time.


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## slownsteady (Mar 25, 2014)

The life of the wood will be enhanced by good drainage. You say you have stone, so that is good. Will the bottom courses be sitting in water?

Still considering rock baskets?:

http://en.wikipedia.org/wiki/Gabion


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## NorPlan (Mar 30, 2014)

slownsteady said:


> The life of the wood will be enhanced by good drainage. You say you have stone, so that is good. Will the bottom courses be sitting in water?



 @ slowsteady, in answer to your query..The Bottom Row (6x6) sites level resting on top of the culvert pipe which is out of the water, even with Spring Runoff in the mix...It has be concluded that poor drainage and water allowed to back up causing the existing Retaining Wall to become saturated with water through time (7 years)...


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## NorPlan (Mar 30, 2014)

slownsteady said:


> Still considering rock baskets?:
> http://en.wikipedia.org/wiki/Gabion




:hide:  @ slowsteady..After some short Deliberation with My Job Planner and the One who affords me with the title of Professional Tool Caddy..We will go with Rock Baskets...Drainage is the Operative Word, Management feels the build up of pooled water will have many places to drain...lol...


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## Jimmy (Mar 30, 2014)

Just throwing this out there since I have seen it a lot in my line of work.
Do you plan to replace the culvert pipe and do you know its condition?I have witnessed a lot of people with beautiful new drives and retaining walls that failed due to an old pipe.


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## NorPlan (Mar 30, 2014)

Jimmy said:


> Just throwing this out there since I have seen it a lot in my line of work.
> Do you plan to replace the culvert pipe and do you know its condition?I have witnessed a lot of people with beautiful new drives and retaining walls that failed due to an old pipe.




:agree:  @ Jimmy...Point Well taken, Yes looks are deceiving on the outside considering the actual age of the house..I'm going by the age of the house when it was originally built from the foundation on up...The Township installed the Pipe in the late 70's , laying down a bed of 2" stone 1st...Then more 2" stone on top to create an access to the property.. I guess you could say one advantage of the Rock Cage concept, if the Galvanized Culvert Pipe went South...We could dismantle the Retaining Wall without to much effort, then trench to the otherside as it slopes on that side...Cheers..


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## slownsteady (Apr 1, 2014)

> Drainage is the Operative Word, Management feels the build up of pooled water will have many places to drain...lol...



sounds like a plan! It makes a lot of sense. I think the next step after the wall is built is to clear the downstream area so the water just keeps moving.


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