Concrete Wall failing to be supported by Segmental Retaining Wall

[jaggars]

One of the architect has come out with a option of putting a Segmental Retaining wall in front of a failing poured in place retaining wall the ht of this wall is 7.0ft at the highest point and its retaining parking lot.They are not willing to take down the existing wall considering that its already is leaning and looks like its moving forward.They have asked me to look at the option of putting a SRW wall in front of it. My concern is i still have to account for the forces of active earth behind the concrete wall i have to put a geogrid/use bigger blocks to design. I want to get some thoughts do i have to take any other forces. I am assuming as if the existing retaining wall is not there but given that the client does not want to remove this wall i am not able to come out with a bigger block to design for a 7.0ft wall.Any other options?

 

[MSEMan]

Perhaps you'd be best starting with an analysis of why the wall is failing. By "moving forward" do you mean sliding, or do you mean rotating about the toe, which is actually more like leaning or rotating? If the wall is rotating it may be a bearing failure? If you can put a wall in front of the existing wall it kind of begs the quesiton of why its there in the first place.

 

[fattdad]

To leave a 7 ft tall wall in place and construct an SRW in the foreground, you'd need about 5 ft of real estate to allow for the grid length. I don't get it. . . .

I'd agree with MSEMan - why is the original wall failing?

f-d

¡papá gordo ain’t no madre flaca!

 

[jaggars]

thanks for your replies.
i checked wall is failing because of Base sliding its moving forward not leaning(not a bearing failure).There are some block manufactures like unilock and redirock they have a big machine place stones whereby they can go as high as 7.0 to 8.0ft without grid some of these system have front to back depth of almost 2.0ft.They original wall was designed about 15 to 20 years ago.

 

[MSEMan]

if your wall is sliding the most cost effective remedy may be to anchor it in situ. You can core through the facing and install tie backs. Alternatively, could you drive a row of precast piles in front?

 

[jaggars]

Thanks for all your replies. I would put this option to my client.If they still want to go ahead with a SRW wall would it still be feasible? From what i understand they client want to develop this property into high end residential scheme so he would want to go with something architectural but still want to adopt the most cost effective remedy.

Thanks

 

[DRC1]

I agree with the anchors. May need strong backs and wales to distributeOnce the wall is stabilized, you can pour a facacde in front. I think if you try the SRW approach, you will find you have a problem with two walls instead of one. Typically gravity walls need less than a 4:1 Height to base ratio to be stable