Does anyone know a good method to repair cracked masonary blocks. I have a situation where I have a block wall that has a almost completely vertical crack, crack goes through mortar joints and through the blocks themselves. The joints can be tuckpointed, but I am not sure the best approach to repairing the cracked concrete block itself. See attached picture.
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Cracked CMU Block Repair 2
- Thread starter DWHA
- Start date
msquared48
Structural
I'll think about it BA... ![[bigsmile]](/data/assets/smilies/bigsmile.gif "[bigsmile] [bigsmile]")
Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask
Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask
Agree with a2mfk...the foundation wouldn't necessarily show any distress from settlement, but the wall would.
Further photos imply other than settlement, but would be good to find actual cause. As Mike noted, water intrusion appears to be an issue, so seal it, even if it looks awful for a while.
Further photos imply other than settlement, but would be good to find actual cause. As Mike noted, water intrusion appears to be an issue, so seal it, even if it looks awful for a while.
- Thread starter
- #23
Ok. I have had a chance to look at the design drawings. Control Joints are at 48’ spacing. Vertical Cores reinforced at 4’ cts with a #5 bars, grouted solid. Horizontal truss type reinforcing at 16” cts. There is a CMU beam with a total of 8 - #6 bars (Beam is 3 courses, 24” tall) directly above the door jamb.
"There is a CMU beam with a total of 8 - #6 bars (Beam is 3 courses, 24" tall) directly above the door jamb."
That outta hold 'er!!
I wonder what that is about, and if it was built that way. That is not a continuous bond beam, that is just the lintel huh? Something like a mezzanine beam or joist girder in that area? If it was built that way, I guess local deflection of that lintel may be ruled out
That outta hold 'er!!
I wonder what that is about, and if it was built that way. That is not a continuous bond beam, that is just the lintel huh? Something like a mezzanine beam or joist girder in that area? If it was built that way, I guess local deflection of that lintel may be ruled out
- Thread starter
- #25
msquared48
Structural
DWHA:
Did you verify IN THE FIELD that the bond beam is actually there? It may have been placed for a future mezzanine that was never built, or may have been eliminated if the mezzanine was eliminated.
Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask
Did you verify IN THE FIELD that the bond beam is actually there? It may have been placed for a future mezzanine that was never built, or may have been eliminated if the mezzanine was eliminated.
Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask
- Thread starter
- #28
The crack pattern throws considerable doubt as to the presence of a continuous 3 course bond beam reinforced with 8-#6 above the door head. It would not have been easy to get that much reinforcement into an 8" x 24" CMU beam. Or perhaps it is 10" x 24"?
The bottom course of the bond beam appears to be less than 8", so the beam height is probably closer to 22" than 24".
BA
The bottom course of the bond beam appears to be less than 8", so the beam height is probably closer to 22" than 24".
BA
msquared48
Structural
Control joints at 48 feet is a littttttttttttttle far. Usually they are in the neighborhood of 25 feet, plus or minus. This could be the major reason the the cracking seen.
As for the (8) #6 in the 24" bond beam, it is probably there considering the crack pattern seen at the doorway in your photos - they are much tighter together and spread out in the vicinity of the beam, which would be understandable.
Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask
As for the (8) #6 in the 24" bond beam, it is probably there considering the crack pattern seen at the doorway in your photos - they are much tighter together and spread out in the vicinity of the beam, which would be understandable.
Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask
msquared48
Structural
Sorry BA... Here we go again! We were typing at the same time.
Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask
Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask
msquared48
Structural
In thinking about this more, BA was initially coirrect in his assertion of the problem being temperature related, not settlement.
What is happening is that the 24" deep bond beam is constraining the cracking just above the door jamb, making it appear that it is settlement related with the varying crack width.
The problem is temperature related, not settlement. I'm sure of that now.
Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask
What is happening is that the 24" deep bond beam is constraining the cracking just above the door jamb, making it appear that it is settlement related with the varying crack width.
The problem is temperature related, not settlement. I'm sure of that now.
Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask
Don't forget, I saw a step crack, i saw a step crack! (second pic)
If I was writing this up I would say that "Settlement is a potential contributing factor to the cracking observed in the CMU walls, but the main contributing cause is likely expansive/shrinkage movements within the CMU walls and a lack of properly placed expansion joints."
That'll be one beer if you use it, uhmmm, Hoegaarden will do.
And I would still do the other stuff I said above, call me conservative but I am not a fan of those cracks. And I'd add expansion joints and filled cells to each side of them, at least where the wall already cracked.
If I was writing this up I would say that "Settlement is a potential contributing factor to the cracking observed in the CMU walls, but the main contributing cause is likely expansive/shrinkage movements within the CMU walls and a lack of properly placed expansion joints."
That'll be one beer if you use it, uhmmm, Hoegaarden will do.
And I would still do the other stuff I said above, call me conservative but I am not a fan of those cracks. And I'd add expansion joints and filled cells to each side of them, at least where the wall already cracked.
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1
- #35
a2mfk,
Settlement is not the only reason for stepped cracks. Diagonal cracking at ends of walls is also a typical type of restraint shrinkage cracking. The footing/stem wall restains the wall at its base, and the body of the wall shrinks up and away from the end.
Settlement is not the only reason for stepped cracks. Diagonal cracking at ends of walls is also a typical type of restraint shrinkage cracking. The footing/stem wall restains the wall at its base, and the body of the wall shrinks up and away from the end.
Agreed Hokie. But since all foundations settle to some degree, its hard to eliminate it as a contributing factor, even if very minor. But I would also agree the vertical crack above it would also suggest shrinkage.
Doesn't really change the outcome or repair recommendations, just trained now as a forensic engineer where you have to cover every base in your reports because of possible legal proceedings.
Doesn't really change the outcome or repair recommendations, just trained now as a forensic engineer where you have to cover every base in your reports because of possible legal proceedings.
msquared48
Structural
Personally, I eat waffle(s).
Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask
Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask
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