Horizontal Concrete Wall Crack
Horizontal Concrete Wall Crack
(OP)
We conducted an observation of an 8" by 5'-0" continuous foundation wall recently and observed something that we had not seen before. We observed that the wall has horizontal cracks approximately 3" from the top of the wall on both sides. The wall is approximately 40' long, but the cracks don't appear along the entire length. The wall appears to have been placed directly on ledge on a very steep site. This foundation wall makes the front wall of a unheated crawl space with low and balanced back fill on each side. Both the foundation wall and wood framed wall above checked as plumb. We observed no diagonal or vertical cracking. There is a large cantilevered deck above the wall and we originally thought the damage might be from uplift, but we observed no damage or separation to the wood wall framing, which is all exposed, and the building has no tension resistance system in place other than the exterior sheathing. There is no visual damage to the finished residential space above. So our working theory is that the reinforcing along the top of the wall is corroded due to chloride in the concrete mix design. There is no water staining/damage or visual corrosion that we would normally see. We are wondering if anyone else has seen damage similar to this.






RE: Horizontal Concrete Wall Crack
RE: Horizontal Concrete Wall Crack
RE: Horizontal Concrete Wall Crack
RE: Horizontal Concrete Wall Crack
BA
RE: Horizontal Concrete Wall Crack
RE: Horizontal Concrete Wall Crack
RE: Horizontal Concrete Wall Crack
Two questions:
1. How old is the concrete wall and the wood framing above? New construction?
2. Also, has the wall seen a large uplift force from wind that could cause a crack to develop at an unconsolidated horizontal pour joint?
In looking at the shot along the wall to the left side of the photo, it seems like the wall bends back to the right... An illusion?
Unless the crack literally formed as the concrete was curing from local consolidation , I would think, based on the wall height and horizontal reinforcing, that the stiffness of the wall could span any soft spots in the soil matrix after it cured.
Puzzling problem here...
Mike McCann, PE, SE (WA)
RE: Horizontal Concrete Wall Crack
Mike McCann, PE, SE (WA)
RE: Horizontal Concrete Wall Crack
There is evidence of poor vibration with "rat holes" in a couple of areas.
The building is located right off from a ocean harbor so there would be plenty of chloride in the air. The drawing is also showing (2) rows of reinforcing at the top of the 8" wall. We found one area away from the cracking on the interior where the reinforcing has no cover. So our thought is still lack of reinforcing cover and chloride corrosion. We will recommend opening it up to confirm.
RE: Horizontal Concrete Wall Crack
RE: Horizontal Concrete Wall Crack
RE: Horizontal Concrete Wall Crack
RE: Horizontal Concrete Wall Crack
Gee, where have I seen this before?
Mike McCann, PE, SE (WA)
RE: Horizontal Concrete Wall Crack
BA
RE: Horizontal Concrete Wall Crack
Hard to believe for me BA considering what I mentioned before, as the crack was not along the entire length of the wall...
I would expect some diagonal cracking to be seen from settlement / rotation, unless the wall settled uniformly, where I would see the crack along the entire length of the wall. If uniform settlement also occurred, you could see some diagonal cracking along the end transverse walls, unless the building rotated or settled as a whole.
This is a can of worms...
Mike McCann, PE, SE (WA)
RE: Horizontal Concrete Wall Crack
I hadn't noticed that the crack wasn't full length but it is possible that horizontal bars were placed below the form ties in some locations and above the ties in others. The type of settlement I was considering was the settlement of concrete in the form as it sets, not foundation settlement although that could be a factor as well.
BA
RE: Horizontal Concrete Wall Crack
Mike McCann, PE, SE (WA)
RE: Horizontal Concrete Wall Crack
RE: Horizontal Concrete Wall Crack
RE: Horizontal Concrete Wall Crack
RE: Horizontal Concrete Wall Crack
BA
RE: Horizontal Concrete Wall Crack