# Massive retaining wall fails.



## rrk (Apr 22, 2012)

Rich D. said:


> I know what your talking about.. is it on 46 by the great notch bar ? That wall has to be 100'+ easy


Thats the one, that is huge


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## TimelessQuality (Sep 23, 2007)

I'll bet they take that off their site pretty damn quick:laughing:


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## The Coastal Craftsman (Jun 29, 2009)

asevereid said:


> What they use for tieback into the soil is a geotextile grid...looks like heavy duty snowfence. The grid size mat size, and placement is spec'd by the engineer. It is placed in between courses of block and the backfill material is compacted over it...'tying' the lifts of backfill together. There is typically clean crush placed directly behind the block as well as drain cloth (landscape fabric, or similar material) that ultimately feeds to a perforated drain pipe. Other than that I've understood that common tieback procedures can be used with the Allan Block system, but they tend to offer their geogrid system as a part of the package, or the engineer specs it.


Would that grid not get crushed on the lower courses between the blocks.


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## asevereid (Jan 30, 2012)

BCConstruction said:


> Would that grid not get crushed on the lower courses between the blocks.


I always wondered that myself...but the manufacturer seems to be certain that it won't fail like that.


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## MTN REMODEL LLC (Sep 3, 2010)

asevereid said:


> What they use for tieback into the soil is a geotextile grid...looks like heavy duty snowfence. The grid size mat size, and placement is spec'd by the engineer. It is placed in between courses of block and the backfill material is compacted over it...'tying' the lifts of backfill together.
> There is typically clean crush placed directly behind the block as well as drain cloth (landscape fabric, or similar material) that ultimately feeds to a perforated drain pipe.
> 
> Other than that I've understood that common tieback procedures can be used with the Allan Block system, but they tend to offer their geogrid system as a part of the package, or the engineer specs it.


Thanks Aserver......

Is it a plastic or metal grid..... does it lock to the block.... or just the weight of the block lock it together.....

Was that a picture of ALLEN BLOCK.

TIA


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## rrk (Apr 22, 2012)

I think the tiebacks left with the wall, so the mfg is clear, the landscape architect is the one on the hot seat.


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## wnc viking (Aug 4, 2011)

Why would anyone think a wall that tall would work. It has failure all over it .


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## CENTERLINE MV (Jan 9, 2011)

Yikes.


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## MTN REMODEL LLC (Sep 3, 2010)

rrk said:


> I think the tiebacks left with the wall, so the mfg is clear, the landscape architect is the one on the hot seat.


?????


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## asevereid (Jan 30, 2012)

MTN REMODEL LLC said:


> Thanks Aserver......
> 
> Is it a plastic or metal grid..... does it lock to the block.... or just the weight of the block lock it together.....
> 
> ...


It's a plastic/fibre mix, and that pic is straight from the AB website. The weight of the block is what typically holds it in place.


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## wnc viking (Aug 4, 2011)

How do they get approved to build a wall with that system that tall . It is not hard to see it is going to fail.


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## Moxley-Kidwell (Jan 28, 2011)

Those things are all over the dc and Baltimore area. I've been waiting to see that happen around here also. Not sure if any in this area are that big or not though, that thing IS huge!


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## asevereid (Jan 30, 2012)

They'll build these suckers pretty big...By the way, I'm not affiliated or recommending the use of AB, but it's all I've had experience with; and they seem to stand behind their product.
Here's some projects from their site:
http://www.allanblock.com/case-study/csx-facility.aspx

http://www.allanblock.com/case-study/skyline-ridge.aspx

http://www.allanblock.com/case-study/tocher-residence.aspx

http://www.allanblock.com/case-study/herrick-street-bridge.aspx

http://www.allanblock.com/case-study/jewish-academy.aspx

I believe these walls can be built to suit almost any need with the appropriate engineering, but I'm just an armchair expert, and time will tell how these structures will hold up.


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## wnc viking (Aug 4, 2011)

Think the cold earlier this week then all this rain this weekend had anything to do with it


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## The Coastal Craftsman (Jun 29, 2009)

wnc viking said:


> Think the cold earlier this week then all this rain this weekend had anything to do with it


That's my thinking.


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## blacktop (Oct 28, 2012)

wnc viking said:


> How do they get approved to build a wall with that system that tall . It is not hard to see it is going to fail.


If that wall was built 40-50 years ago .It would still be standing for another 40-50 years..But these days ! It's all about PRODUCTION !
How fast can you put it up and how cheap! 

No one really cares about quality...until there so called quality fails!
Then ya got the ole finger pointing going on! 

I can see that wall going up..And and I know Who slapped It up.


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## asevereid (Jan 30, 2012)

Wow, just found the place...this thing is HUGE.
Impressive,


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## concretemasonry (Dec 1, 2006)

Allan Block has a very long history documented, similar the other products that are essentially the same concepts. They have be used for over 25 years internationally successfully on larger applications.

I have seen the tests of the reliability of the geogrid anchorage reliability in moist/wet conditions and some with minor vibration.

Something with the engineering design oe the construction, since some contractors do not appreciate/understand the basics behind the system and what is really important. - Could be soil, drainage, compaction or details.

Some of the local copies/knock-offs can be more susceptible to problems because of details omitted and quality control.

These type of systems rely on tying the soil behind the wall together with layers of grogrid to create a solid mass that is capable to flex with conditions. - Too often people just think they are dumping dirt with no controls.


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## Kowboy (May 7, 2009)

From the Allen Block FAQ:

"Site and soil conditions determine the maximum height on any project."

If that fence is 6' high, that wall is about 75' high.


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## Fouthgeneration (Jan 7, 2014)

The arch is going the wrong way, Block pushed out 1/16" of an inch the wall is weaker instead of stonger, there is no redundant load path, one block fails/ kick out = failure of all above.

Where are the water drains or tiles????? huge amount of run off and sub surface water, what intercepts it prior to the back fill being fluidised?

I actually think the set back cast into the allan block is to much for this application, it prevents the mass of upper courses of retaining wall from bearing on the lower courses thus the lowest courses have only a fraction of the mass of the top pressing them together, but the earth retained has the weight of itself + the walls mass transferred to it by all the block above the 10 or 12th course.

I'd love to see if the lips of the block that remain are intact or if the back lips broke on the displaced units? 
When excavated, did the contractor dig out flat shelves every so often vertically, or just peeled back so many feet to a monoslope?
Looks like they should bought some Earth nails to install along with the mesh.


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## Irishslave (Jun 20, 2010)

I'm going to say that compacted earth is heavier than water and it shifts and freezes and thaws...so every bit of engineering that goes into building a damn should go into any retainer of comparable size a failure could be equally catastrophic especially in a deluge


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## The Coastal Craftsman (Jun 29, 2009)

asevereid said:


> Wow, just found the place...this thing is HUGE. Impressive,


 Yeah its a cool wall. The one at the back is even larger. I would guess that whole area of wall could be prone to this issue now so what happens? You drive up it in a rain storm and it has a landslide and kills everyone. This should be interesting as I'm sure its gonna happen again.


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## Patsfanindallas (Aug 27, 2013)

This is the side of a highway. Trust it?


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## The Coastal Craftsman (Jun 29, 2009)

Patsfanindallas said:


> This is the side of a highway. Trust it?


Well found out some more info. It was 30 courses failed. Geo grid still in place and goes 40ft back behind the wall. There was so much hydrostatic pressure it blew the locking pieces out of the blocks lower down then the wall and all above it failed. He said it was holding back an unreal amount of water. They have no idea why its building up behind the wall either.


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## Fouthgeneration (Jan 7, 2014)

Rule # 2 of retaining walls. install drainage so owner can SEE the water leaving the backfill. why didn't the wall have weep holes in its face???
I'm guessing the same foools cheaped out on the washed rock back fill and used spoil from the excavation for some or most all the fill.


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## Uncle-chicken (Jul 22, 2013)

And suddenly, any screw up I've ever made doesn't look all that bad...


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## MarkJames (Nov 25, 2012)

That thing looks just too damned vertical. Advanced engineering at odds with the basic laws of physics in nature over time.


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## rrk (Apr 22, 2012)

Fouthgeneration said:


> Rule # 2 of retaining walls. install drainage so owner can SEE the water leaving the backfill. why didn't the wall have weep holes in its face???
> I'm guessing the same foools cheaped out on the washed rock back fill and used spoil from the excavation for some or most all the fill.


That's why I said the Landscape Architect would be on the hot seat. There should have been some drain pipe through the wall to remove some of the water behind the wall.
I'm sure no body in charge wanted to see a few pipes coming through their beautiful wall.


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## rrk (Apr 22, 2012)

Patsfanindallas said:


> View attachment 105998
> 
> 
> This is the side of a highway. Trust it?


At least that one has some, maybe not enough weep holes through it.


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