Replace wood posts holding up a retaining wall

I have a 2' tall retaining wall in my garden. It consists of 6x8 railroad ties, set on edge. The rr-ties are laterally supported by treated 4x4 lumber posts, imbedded about 1' into concrete supports poured into the soil on the low side of the wall. there is no concrete footing for the RRties, they are set on the soil.
All this is now 30 years old. The RR ties are still in good shape but the treated 4x4 have rotted/broken-off at the base of the wall. Therefore, the RR ties are slowly being pushed downhill, collapsing the wall.
If I could replace the 4x4 posts in their cast concrete bases, I could easily re-align the RR ties. How can I replace the 4x4 posts, set in concrete? Do I need to dig out the concrete base and re-pour new concrete around a new post? That's hard work for an 85 year old.
Thanks for any help
Walter
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www.rationality.net


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On Thursday, January 15, 2015 at 11:16:41 AM UTC-5, Walter E. wrote:

If the old 4x4's have broken off at the cement line or can be cut off there and covered up with some soil, mulch, whatever, then it's probably easier to just put new 4x4's embedded in concrete in new locations. That way you don't have to remove the concrete that's there. That assumes that visually it's OK, ie that it won't look like hell because the area of the wall where the old 4x4 were doesn't look different, etc.
Curious though how you're going to "easily" re-align the railroad ties. If they've shifted, with dirt behind them, that typically isn't easy, unless maybe you have a tractor to push it with.....
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Yes, there is probably no easy solution. Will have to bite the bullet and dig new holes for the posts. As to aligning the RR ties: I will have to dig out part of the hill behind the ties, lift/push the ties into the proper location and then just leave a narrow gap behind the ties to avoid future lateral pressure of the soil.
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In

Just out of curiosity, I would be interested in seeing a couple of photos of what you have now if you are able to do that.
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Hi Walter,

Are we talking three rows 8" high, or four rows 6" high?
The wall would be stronger if the ties were laid flat, but that does mean an extra row of ties.

Have you dug down on the back side of the wall to see what the back sides of the ties look like? After 30 years I would question whether they're as good as they might appear, especially if the treated 4x4's have rotted.
I had some old ties along our driveway that looked fine from the front, but underneath they were completely rotted away. If your ties are rotted, you're better off building a new wall.

Unfortunately, there's no easy way to repair your wall. You'll need to dig the dirt back from behind the wall to position the wall back where it used to be. You probably won't be able to just push things back into alignment. It would probably be easier to take it apart and reassemble in the new position.
Granted, this won't be easy at 85, or even at my age of 51. Maybe you can find some young bucks with more brawn than brains? :)
Two feet is not an overly high retaining wall, but it's usually the water in the soil that pushes it forward. You can help reduce the problem by installing drainage pipe, gravel, and landscape fabric behind the wall. Then route the drain away from the wall.
If you have room, you might be able to save some work by rebuilding the wall in front of it's original position. That would give you room to install drainage behind the wall without digging a lot of dirt.
If it comes down to rebuilding the wall, you may want to look at other options. Precast blocks are popular and widely available, but they can get expensive for long walls. Or, you can dry stack rocks with a slight backward slope. You could build forms and pour a concrete retaining wall. Or, you could do what I did and build a mortared stone retaining wall:
http://www.watsondiy.com/2008wall.htm http://www.watsondiy.com/2009wall.htm
If you decide to stay with railroad ties, you could probably forego the 4x4 posts. Just overlap the rows of ties, stepping each row back slightly. Then drill holes down through the ties and anchor them together with sections of rebar. If the wall is very long, or the soil slopes uphill behind the wall, you might want to install a "deadman" behind the wall every 8' or so. The first row of ties should also be buried below ground level to prevent the bottom from being pushed out (alternatively, you might be able to drill holes into the old concrete from the 4x4's and anchor to those).
Good luck with your project!
Anthony Watson www.mountainsoftware.com www.watsondiy.com
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This is what one segment of the RR ties looks like. There are several more that need repairs, maybe to a total of 20 (160')
http://postimg.org/image/834wlwkab/
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