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6 foot cantilver balcony over retaining wall

6 foot cantilver balcony over retaining wall

6 foot cantilver balcony over retaining wall

(OP)
Greetings,
I am looking to design a 6-foot concrete balcony which will project over a concrete MSE wall.  The soil side of the wall will be 6-feet long, and can tie into a sizable (4x4') concrete footing.
Has anyone had any problems with such a light load over an MSE?  I often see culverts and parking placed adjacent but not over.
Thanks for your suggestions.

RE: 6 foot cantilver balcony over retaining wall

I don't think that standard MSE walls are intended to support vertical gravity loads from other structures.  You could call an MSE wall supplier like Keystone to verify.

I would expect that there's be some type of foundation on the earth side of the wall that would support the cantilever over the wall.  This foundation would most likely need to be deeper - to avoid additional lateral thrust on the MSE wall system.

 

RE: 6 foot cantilver balcony over retaining wall

Agree with JAE,a few piers all to do the job.

An expert is a man who has made all the mistakes which can be made in a very narrow field

RE: 6 foot cantilver balcony over retaining wall

MSE walls can carry additional loads and are often marketed to carry bridge abutments as spread footings.  Sometimes in very tall walls, the higher layer is offset a bit but still sits atop the lower MSE wall.  

Now for a few reality comments.  I have never a spread footing bridge abutment on a MSE wall in the midwest.  I have seen details in the Ohio DOT bridge manual for it though as well as in Reinforced Earth COmpany's (RECO) online material.  

In our office we check the bearing (of the original soil)  and stability of the whole wall and whatever loads on are it.

You should consider the impact of what you're placing on the MSE wall due to strap maintenance or any future excavation that may need to be done which will impact the MSE fill.

 

Regards,
Qshake
pipe
Eng-Tips Forums:Real Solutions for Real Problems Really Quick.
 

RE: 6 foot cantilver balcony over retaining wall

Reinforced Earth walls in industrial/mining environments are often designed with footings behind the wall, founded high in the reinforced gravity wall.  Reinforced Earth can provide designs for this.  But you can never bear on the concrete, because the panels are just the facade, not the structural element.

RE: 6 foot cantilver balcony over retaining wall

Qshake - most MSE walls I've seen in front of bridge abutments do not carry the bridge - rather - the abutment is on piling behind the MSE wall and the wall is just to hold back the earth around the abutment.

 

RE: 6 foot cantilver balcony over retaining wall

JAE - I quite agree and made the note that in my earlier post - I've never (seen) a spread footing on an MSE wall in the midwest.  However, the concept is acknowledged and dicsussed in the FHWA publication on design and construction of MSE walls.

And for the record here since many of us are talking about on or behind the wall, the MSE wall is the entire granual backfill with straps that includes the concrete face panels.  The face panels are not, however, the reason the wall retains fill, it is the granular fill reinforced with straps that do the retaining.  

Having noted that most pile endbents for bridges are founded in the MSE wall not behind it.

I had hoped to point out that structures are often designed to sit atop MSE wall fill provided the bearing pressure of the original insitu soil and stability are checked for both the new MSE wall and whatever will sit atop.

Thanks!

Regards,
Qshake
pipe
Eng-Tips Forums:Real Solutions for Real Problems Really Quick.
 

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