Reinforcing concrete retaining wall

[Anton Polyakov]

Hello folks. I am not a structural engineer hence seeking an advice from experienced folks out there.

I have an L-shaped concrete retaining wall comprised of two cold joined pieces with large footing. I would like to attach a new perpendicular wall to it which will serve two goals:
1. joining two pieces together
2. fortifying the existing wall preventing it from falling over.

My idea is this new wall will go perpendicular from existing wall step-wise up hill holding the existing wall in place. Now I have a question of how to best attach the new wall to the piece-wise existing wall. So far I came up with this idea:
- get a square beam, drill through it and bolt it through washers to both pieces of the existing wall
- form a T-shaped new concrete wall around it (so its footing will span between both pieces, it will look like an electrical socket plug basically)
- weld the square beam to internal rebars in the newly poured wall

Do you think this is reasonable? Sorry if my explanation is cumbersome, hope a picture can clarify it

 

[GeorgeTheCivilEngineer]

<insert standard 'hire an engineer' response>

Is the existing wall showing signs of movement?
Why do you want to join then two sections of wall together? This shouldn't be necessary.

 

[HouseBoy]

GTCE is right .... but some more questions and other thoughts :

I assume you are trying to stabilize (or improve the stability) of the existing wall at the location of the existing construction joint.
My questions would have to do with -
How long is the wall on each side of the joint?
What is the horizontal reinforcing in the existing wall?

In order for the new wall to be effective, the existing wall will need to be able to span horizontally to it.

There might be much simpler details than what you are showing but... much will depend on the specifics of what you are trying to accomplish and/or why does the existing wall "need" to have the perpendicular wall added AND WHAT ARE THE DIMENSIONS INVOLVED.

 

[BAretired]

Get an engineering assessment. You may not need to do anything to the wall.

BA

 

[Anton Polyakov]

Hello folks

I spoke to an engineer actually and in general he thought building this new wall is not a bad idea. Let's be clear here - I know I might not need it and existing wall does not yet show any signs of failure, but I still want to have it 110% certain that nothing will move. And as I am pretty enjoying the process of building it, I don't mind it.

The reason I am doing this is two fold:
1. The footing of existing wall sits on a steep soil on top of bedrock (imagine a standard soil covered bedrock with trees, grass, etc) and some portions of that is on true bedrock while some portions are not, siting on a 30-40 cm of soil on top of bedrock.
2. I am going to increase soil pressure on the existing L-shaped wall. Before it was holding basically just non-compacted soil under the deck. Now I want to build a solid concrete floor on top of it and actually compact the soil which this wall is keeping.

In my mind this perpendicular wall will decrease chances existing wall will slip down the hill or flip. Plus it will provide a good support for concrete on top (not huge amount, standard 4 inches slab). Here is another attempt to draw it (sorry about my drawing skills, I should probably do it in Sketchup3D or smth). I left dimensions on the picture, they are:
- overall L-shaped wall length: 2x 7.5m (2 pieces each 7.5m long with cold joint in the middle)
- L-shaped wall height: ~1.5m
- L-shaped wall thickness: 30cm

- new wall length: ~5-6m
- new wall height: matches existing wall (1.5m)

What would people say about connection of two walls form my original post?