Hello. We've been asked by a client to comment/advise on a short (3'-5' tall) reinforced concrete retaining wall that has been constructed and is showing cracking at locations between expansion/contraction joints provided at roughly 20' oc. The client suspects that the contractor did not discontinue the rebar at the joints or provide a slip on one end. Vertical cracking is showing exclusively at weep hole locations, full height. The wall is an aesthetic feature, and efforts to patch the crack with injected epoxy and thin mortar layer have not been successful - the cracks return. What would be the risk in cutting the rebar at the joints at this point? Would that relieve the stress such that a patch of the existing cracks would stay closed? Other ideas? Thank you!
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Retaining Wall Cracking Between Joints 1
- Thread starter JoPap
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bridgebuster
Active member
If you cut through the wall at the expansion joints nothing will happen to the wall.
If the contractor did in fact discontinue the bars it could be that your joint spacing is too large for a low rise wall.
If the contractor did in fact discontinue the bars it could be that your joint spacing is too large for a low rise wall.
msquared48
Structural
Since this is at weep hole loctions, I would also consider freeze-thaw action in the area of the weep hole that it could be encouraging the vertical cracking.
I do think that the horizintal rebar scenario is the most likely though as previously mentioned. With this though, if the bars are at the center of the wall, the cut will have to be in the order of half the wall thickness.
The epoxy injection into the cracks will not work. It is too rigid. You need a flexible sealant - something that will move but remain sealed and bonded with a variation in temperature.
Mike McCann
MMC Engineering
I do think that the horizintal rebar scenario is the most likely though as previously mentioned. With this though, if the bars are at the center of the wall, the cut will have to be in the order of half the wall thickness.
The epoxy injection into the cracks will not work. It is too rigid. You need a flexible sealant - something that will move but remain sealed and bonded with a variation in temperature.
Mike McCann
MMC Engineering
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1
- #4
Concrete walls restrained by previously placed footings or slabs will invariably crack at about 10 to 12 ft spacings. More reinforcement will control the cracking, but nothing will completely prevent it. The cracking will be much more noticeable in low walls as in this case.
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