Masonry wall failure

[mark1234]

I am offering a repair to an existing CMU wall... about 50 years old. It's a foundation wall to a residential one story and roof supported wall.

Ceiling height is 7'-6" and grade is above at almost 8'-6". The soil in the area is known to have clay and the soil slopes towards the wall.

The walls are deflecting about 1.5" at mid-span.

Another wall, built at a later date as an addition, is deflecting the same with large horizontal cracks at the mid-span mortar joints and a large displaced crack horizontal near the S.O.G.

I am thinking about grouting the walls solid and using carbon fiber strips.

Was wondering what other types of repairs you guys have provided for this type of situation?

Regards,



MDJ

http://www.windspeedbyzip.com

http://www.groundsnowbyzip.com

 

[civilperson]

Dig out the soil adjacent to the wall and replace the fill with compressible foam.

 

[vandede427]

Whatever civilperson suggested does absolutely nothing to strengthen or stabilize your wall.

The grout and carbon fiber won't get the bow out of the wall, but it will strenghten the out of plane strength of the wall, and have the smallest projection off the interior face of the wall.

If a projection off the interior face of the wall is not a problem, then perhaps bolting a steel plate or angle to the wall at every 4' or so after the wall has been grouted, may be a cheaper option than the carbon fiber. The simple steel members are more readily available and more familiar to the everyday contractor than trying to find somebody to install crp.

 

[beton1]

We have used HSS sections (size & spacing depending on loading), fastened at top to wood structure, and braced, and then extending into slab (cut out part of the slab). A small footing may be required if the slab on grade is not suitable to provide the lateral resistance required. Grout/shims between HSS and wall or weld clips tight to wall. Externally, make sure water flows away. Digging exterior side and replacing with free draining material may help the overall wall performance. Likely parging repairs and possible waterproofing may be required as well.

 

[MiketheEngineer]

There are a number of ways to repair and reinforce this. Look up "basement" in the yellow pages. Each guy will have a different idea - most work to some degree or another.

Do you want to pull the wall back in line... use some deadmen in the yard with 1'' rod tie backs and pull the walls back.

Don't forget to excavate about 1' to 2' of soil away from the wall first and install drainage tiles, maybe a sump pump and rock backfill.

This is the simple version.

 

[bigmig]

MiketheEngineer is right It depends on a lot of factors but most importantly project budget. Can you tear it down, rebuild it, and get an excavator back there? Getting the bow out will involve major time and expense. Perhaps you could stabilize it like others have mentioned, and then shotcrete the face, essentially re-plumbing the wall with a topping. My only definite suggestion is fix your surface drainage as this could be the cause of a lot of your problems.

 

[concretemasonry]

What is above the top of the wall since the wall height is less than the height to grade? You may be facing a situation where the wall was not designed for the current lateral load and there may be other consequences than a "classic" horizontal crack and the deflection. What kind ot structure is above the deflected wall and how did it transfer the loads? Assumptions on connections will not go far on failure investigations.

It sounds like you are looking for a repair and not a correction of the problem causing the old failure.

Usually, with the normal horizontal crack at or near the midpoint of the wall, the obvious method to to excavate and drain to get the soil pressure down to a realistic level and then straighten/plumb the wall and either place reinforcement and grout in the cores or to attempt a surface repair method.

The wall has already failed because of the soil pressure.

Often, the original design assumptions can lead to some strange designs.

dick

 

[kslee1000]

I suggest at least to post a cross section view showing the wall, the retained soil, and the residence to let people have better understanding the situation. Your description is quite puzzling.