Block wall falling

[SKJ25POL]

Hello everyone,
I would like to get your onion and help on this matter. I am being asked to fix this problem which is not my specialty.

A storage building made of 2' x 2' x 6' concrete blocks stack on top of each other and a fabric enclosure sat on top.

The wall is made of four course and there is no reinforcement.
The only sit on very small keys along the blocks.

The back wall is becoming mis-aligned and the top blocks overturning.
The owner has put some steel bracing and seems is not solving the problem

I don't know where to start, to me is not a solid gravity wall because is not one piece but stack of loose blocks
What the solution and direction appreciated

Any reference - sample old calcs?

 

[SKJ25POL]

oldestguy (Geotechnical),
Again me, I've been questioned that what is the benifit of laying blocks behind existing wall in the second layer parallel to wall?
Why not all blocks in all lawyers run same direction (which is perpendicular to wall)?
I appreciate provising a reason for this idea proposed by you.

Thank you

 

[oldestguy]

Laying blocks in layers, each 90 degrees from that below is a binding effect. You want this to result in one solid unit, especially acting like a beam on its side. Remember that shear needs some transfer resistance mechanism such that you don't necessarily want to rely only on the cementing effect of the grout. Ideally this wall will be one long unit which resists the loader pushing at any place, using the gravity and sliding resistance all along it, full length. If the wings on each end can be tied in, so much the better. That's where this "jack of all trades" supervisor comes in.

 

[SKJ25POL]

So the 90 degrees from below is only useful and effective as long as we use cement/ mortar or glue the blocks to gather?

If they are loose on top of each othe the 90 degrees will not be effective, rigth?

Thank so much and also this project is in U.S.

 

[oldestguy]

The "gluing" helps greatly, but without it, there is still some resistance. However, without "glue"you won't have the full unit available for resistance against the loader.

As to the blocks, stop in a any ready mix plant and look around. Likely they have them stacked somewhat and you can see what is available. My experience with them is they are remarkably strong, even made from reject concrete at times. One project could could not have met budget if it were not for their lower cost than fancy manufactured blocks. Some landscaper material suppliers (stone, bark, etc) use them for retaining the products, but they don't have loaders doing damage.

 

[SKJ25POL]

oldestguy (Geotechnical,
Thank you very much for all your kind and expert assistance.
I greatly appreciate it.

Also I really did not mean to insult anybody by posting the question in Geotech forum. I just was trying to get Geotech people opinion.

Again thank you very much.
Respectfully,
SKJ25POL (Structural)

 

[oldestguy]

Here is another option.

This alternative is assuming you are using a cement - sand grout between all members, horizontal and vertical, and you build a double thick wall, one behind the other. However, it will be necessary to tear down the present wall so that every course will have a layer of high strength geogrid laid between blocks. That grid purpose would be to tie the two walls together to create that one solid "block" of concrete. The projections and indents in the blocks will help anchor that grid also.

Do not substitute a commercial mortar mix for the cement-sand grout. They usually contain fillers and the bond strength of those mortars is way below that of a cement-sand grout.

This alternative would be easier to build and the grid tends to tighten up as the blocks are laid on it, stretching over those projections.

A stability calculation still is required to be sure it works and setting details, such as dowels in the slab.

 

[SKJ25POL]

oldestguy (Geotechnical,
My boss suggesting me to use some wear steel plates against back wall (inside) attached to wall do u know by chance what is common industry practice for these plates? What type of steel? How thick? and how to attached it to the block wall?
What are possible problems?

I did not want to post a new ad but I really cant find any information off internet.

Thank you

 

[oldestguy]

In my view adding a "wear" plate inside the wall will accomplish one thong only. It will add to the cost of things and do little to nothing in the way of preventing the wall from deforming as it has. Being a structural engineer, try to show the wall would have more significant resistance to moving with the plate there. It would be a combination of structural as well as static gravity wall evaluations.

If I were in your shoes having an owner that has his own ideas on how to fix the problem, but does not want to "do it right" so it works for years to come, I'd say "good bye" and chalk up the time spent as another experience to fade into memory. Now and then we have to bite the bullet and walk away.

From my point of view, if there were other members here with different ideas that would work, you would hear about them.

 

[concretemasonry]

I don't think will find an "common industry practice" because of variable situations. You are using the wrong type of wall material (mafia block) for an 8' high wall. Apparently there is a drive to use what is available and on hand to save money.

An 8' high gravity wall with heavy equipment operating in the area under little supervision could be a red flag. There is little reasonable documented information on the performance, probably because no one expected it to be used permanently.

We had 8 similar bunkers made from 12" reinforce block or reinforced concrete. There very often accessed by a big front end loader at night(24/7 operation) and never had a real problem. They were only 6' high because we wanted the "peak" of the aggregate to be less than 8' for safety and OSHA possible problems.

Just a different slant.

Dick

Engineer and international traveler interested in construction techniques, problems and proper design.

 

[PEinc]

If you don't want this block wall to fall over from the material load inside the storage area, you need to place an approximately equal amount of soil around the outside of the block wall. This will provide more than enough resistance to the blocks pushing out. The block wall would then need to be stable enough to support the outside fill when the inside is empty. The outside fill should also provide enough passive resistance to prevent the loader from pushing over the blocks. Then, to keep the loader from lifting any courses of blocks, you may need to install the steel plate armoring on the inside face of the blocks. I also think that 8' is very high for stacking a wall of 2' thick blocks, as shown in your photo. I see this all the time when driving around, but it doesn't work very well on paper.

http://www.PeirceEngineering.com

 

[SKJ25POL]

I am sorry if my recent question was not clear.
The steel plate on inside wall is intended being added in addition to laying blocks on the outside of wall.
The peupose of the paltes are to minimize concrete chip and scraping by the loader's blade.
Dont know what's the practical size of that plate (thickness) and the type of steel plate (structural or scrap steel)?

Any body has a sample photo to show a actual one.

Thank you

 

[oldestguy]

Hey, a few more ideas. On PE's fill idea, maybe that loader guy can be kept busy adding that fill and in the process may move the blocks back where they first were placed. Only don't let him do that if the bin is empty at the time unless carefully supervised. Might push too far.

 

[SKJ25POL]

oldestguy (Geotechnical),

Is it possible to mortar the 2 x 2 x 6 blocks?
What about gluing them? What are typical practical common glues? Brand name?

This is for the option of setting blocks behind wall, just to stablize them better.

Thank for any direction

 

[oldestguy]

OG back here. Mortar or grout, either have "gluing " properties. Getting the bond down between the new and the old at the vertical joint will not be perfect, but any "glue" there will help. There are epoxies that also can do the job, but expensive. Be sure all surfaces to get the mortar or grout are clean and DRY. A dry surface will absorb some of the molecules and improve the bond. If you want to improve on that, first brush on (as with a broom) a cream consistency made from Portland cement and water. The grout or mortar should be applied immediately after that. In my experience this sort of bonding is stronger than the concrete itself. Oh, don't use commercial mortar. Mix your own. Many of those mortars have fillers made from ground limestone. Masons don't like strong mortars because they are difficult to clean off finished surfaces. The easiest way to do this is with Portland cement grout and the "cream" mentioned.

 

[PEinc]

I think that trying to mortar or glue these blocks is a waste of time and money. The wall looks like it is being pushed over. The blocks need to be backed up with some passive resistance (either soil or more blocks) and the front side needs to be protected from the loader bucket (steel plate).

http://www.PeirceEngineering.com

 

[SKJ25POL]

The block manufacturer tells me due to weigth of blocks the mortar between will seep from joints?
Also I am not talking about between existing wall and pile of blocks, I am trying to bond the layers you draw a stecth for.

 

[oldestguy]

All I can add is cutting corners from what is likely to work, is going to result in "You get what you pay for". Also, the block guy evidently is not a mason. Try a mason for that question.

 

[oldestguy]

One final observation. The way this appears to be going, I suggest that you let the boss know that this is an unusual situation, not normally designed. As a result, perhaps he hires a consulting engineer that is well experienced in unusual situations. Getting the design from this web site probably is OK for that person wants hints as to what to do, but now it does not appear suitable under your circumstances.