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View Full Version : Retaining Wall at Entrance to Laneway...


NorPlan
Jul 6, 2013, 04:19 PM
6 years ago I had widened our laneway... Turning into our laneway there is a Ditch as you enter... At the time it was a simple job as there was about 8ft. Of culvert pipe sticking out the oneside... The Ditch is your standard sloped type.. I used 6" X 6" timbers, by the way there a true 6 inches... Sledge Hammered spikes into them and used steel fence posts on the outside edge.. From the centre top of the culvert pipe to the top of the Retaining Wall it's 4 1/2 ft. high. And stretches 14 ft on top... Now the Neddy Grits.. While the steel fence posts are doing their job the timbers are starting to show signs of drying out after being water logged and starting to split along the top.. The plan is by using the existing wall as a form on one side and digging a trench to build a form for the other side. The idea is to pour a concrete wall... How wide would it have to be and any idea how much concrete I'd need for the Job?? Thanks

joypulv
Jul 6, 2013, 06:06 PM
Will the existing wall hold when you dig the trench (deep enough for gravel and below grade concrete)?
Might there be a water problem that will be too much for the integrity of the soil/gravel under the concrete, and the pressure on the back side of the wall?
It sounds like a daunting project to me, one that might not be able to hold 4 1/2 feet high by 14' long without a very thick wall.
I'd call a concrete contractor for an estimate, just to get an idea of what you are up against.
I'd rebuild the timber wall myself, and put gravel behind it.

NorPlan
Jul 7, 2013, 04:50 AM
Will the existing wall hold when you dig the trench (deep enough for gravel and below grade concrete)?
Might there be a water problem that will be too much for the integrity of the soil/gravel under the concrete, and the pressure on the back side of the wall?
It sounds like a daunting project to me, one that might not be able to hold 4 1/2 feet high by 14' long without a very thick wall.
I'd call a concrete contractor for an estimate, just to get an idea of what you are up against.
I'd rebuild the timber wall myself, and put gravel behind it.


The existing Wall has a slight lean to it away from the side I'd like to trench.. The previous homeowner had a gazillion steel fence posts left over from some project so I had pounded one in the ground about every 2 ft to hold it back.. The lean was caused from me using my Son's jacked up fat tire Jeep, running back & forth to pack the Stone down( everything from 2" pit run, 5/8th's to stone dust ).It's about a 45 / 50 degree slope on each side of the ditch.. So the top 2 rows ( 6 X 6 beams ) stretch the 14 ft. There's a couple of Foundation & Footings Contractors around here but their Busy Busy.. My project is just chump change.. Thanks

smearcase
Jul 7, 2013, 05:42 AM
A sketch or photo would be helpful. A proper concrete retaining wall needs a good steel reinforced footing, steel dowels tieing the footing to the vertical wall, and properly designed wall with reinforcing at the critical points.
In the highway industry, this is a situation where a pipe endwall is used (link below should show a typical endwall application). If you are just considering placing a mass of concrete against the timbers, the weight of the concrete will probably destroy what is left in the life of the timbers.
http://apps.roads.maryland.gov/BusinessWithSHA/bizStdsSpecs/desManualStdPub/publicationsonline/ohd/bookstd/pdf/MD-350.01.pdf

NorPlan
Jul 7, 2013, 05:48 AM
A sketch or photo would be helpful. A proper concrete retaining wall needs a good steel reinforced footing, steel dowels tieing the footing to the vertical wall, and properly designed wall with reinforcing at the critical points.
In the highway industry, this is a situation where a pipe endwall is used (link below should show a typical endwall application). If you are just considering placing a mass of concrete against the timbers, the weight of the concrete will probably destroy what is left in the life of the timbers.
http://apps.roads.maryland.gov/BusinessWithSHA/bizStdsSpecs/desManualStdPub/publicationsonline/ohd/bookstd/pdf/MD-350.01.pdf


If I decide to go the Route of a Concrete Retaining Wall.. The idea was to use the existing timber wall as a form on one side thereby only having to build One form wall.. Once the Cement has set and cured I will tear down the old timber wall...

smearcase
Jul 7, 2013, 06:17 AM
Depends on how deep you go into existing ground with the concrete. The wall wants to rotate away from the road it supports. The portion of footing behind the wall and the reinforcing steel resist the tendency to overturn. You can try your plan but you haven't described your plan in enough detail for me to tell if it has a chance of success.
One point to consider- the existing timbers are already leaning away from the road. If you use that for the front form, the new concrete will already be top heavy and leaning in the wrong direction. Use some lumber (plywood and wedges) to "plumb up" or even lean back the new wall and use plenty of rebar as concrete is weak in tension areas.
Also, consider removing the timbers and placing large stone (we call it rip-rap, approx. 2 foot diameter rocks) instead of concrete. The rock provides a toewall to support the sloped earth backfill. Using care not to crush the pipe.
I'm still just guessing without a sketch or photo.

NorPlan
Jul 7, 2013, 07:08 AM
Depends on how deep you go into existing ground with the concrete. The wall wants to rotate away from the road it supports. The portion of footing behind the wall and the reinforcing steel resist the tendency to overturn. You can try your plan but you haven't described your plan in enough detail for me to tell if it has a chance of success.
One point to consider- the existing timbers are already leaning away from the road. If you use that for the front form, the new concrete will already be top heavy and leaning in the wrong direction. Use some lumber (plywood and wedges) to "plumb up" or even lean back the new wall and use plenty of rebar as concrete is weak in tension areas.
Also, consider removing the timbers and placing large stone (we call it rip-rap, approx. 2 foot diameter rocks) instead of concrete. The rock provides a toewall to support the sloped earth backfill. Using care not to crush the pipe.
I'm still just guessing without a sketch or photo.


For Sure, I realize I'd have to make the existing timber wall True , perfectly level vertically if I was going us it as a form wall on one side... Another Idea for a Wall that has been floated by me is getting a load of Pit Run ( manageable rock the size of your fist or better ) and then using a heavy gauge chicken wire fencing make a square cage 2' x 2' x 1'.. Then lay them down in a Brick Pattern...

parttime
Jul 7, 2013, 07:30 AM
Something like what's shown on the link below? I'm like smearcase, I'd like to see a picture.


A wire cage filled with rock makes for a free-form wall solution (http://www.houzz.com/ideabooks/2292682/list/Gabion-Wall)

smearcase
Jul 7, 2013, 07:40 AM
We call those gabions in hwy construction. We used large ones (3 foot cubes) to build a retaining wall about about 20+ feet high.
There was a problem and it had to be redone because it wasn't designed with a "stepped back" face. Should slope back about 1.5:1 or flatter. You can start wider (depth back from face) at the bottom and step it back for more stable wall. If growth starts in all those nooks and crannies you will hardly know it is there.
I like that much better than a concrete wall without an adequate footing and plenty of properly placed rebar.
The gabion baskets are expensive and are heavier gauge than chicken wire. I would probably try an inexpensive cage made from a less expensive material too, but remember the wall will only last as long as the wire does, unless there is a lot of plant root structure developed. Maybe you can find a good deal on hardware cloth or similar. Good luck.

NorPlan
Jul 7, 2013, 08:41 AM
Something like what's shown on the link below? I'm like smearcase, I'd like to see a picture.


A wire cage filled with rock makes for a free-form wall solution (http://www.houzz.com/ideabooks/2292682/list/Gabion-Wall)





Sorry, @ parttime & smearcase.. That is where my Computer Illiteracy will Shine... lol... I figured the Gabion Wall idea would be expensive... I've got the word out in the neighborhood so hopefully as I had said previously my job is just chump change to a Professional I'll be able to get a professional estimate.. Thanks

smearcase
Jul 7, 2013, 06:10 PM
Let us know how you make out, NorPlan,