cracks in corner of building slab
cracks in corner of building slab
(OP)
Recently poured slab for a 2 story metal building has developed diagonal cracks in each corners. The cracks are in the slab only, the grade beam had poured several weeks ago. Each corner had embedded anchor bolts (in grade beam/foundation). Not a crack pattern that I have seen that I remember. Possibly due to restraint from embedded anchor bolts. There is 4x4 4 gauge mesh in slab and cracks are tight but owner is worried. I have to pull out my form letter that says concrete cracks but am I missing something?






RE: cracks in corner of building slab
RE: cracks in corner of building slab
RE: cracks in corner of building slab
May also be due to shrinkage from the same restraint.
RE: cracks in corner of building slab
RE: cracks in corner of building slab
RE: cracks in corner of building slab
RE: cracks in corner of building slab
RE: cracks in corner of building slab
Dik
RE: cracks in corner of building slab
Mike McCann
MMC Engineering
RE: cracks in corner of building slab
Slab is roughly 80x90 and so far no other cracks in slab, though I expect there to be some. These showed up quickly.
The metal building has a second floor and there is not a lot of lateral force at column bases.
RE: cracks in corner of building slab
RE: cracks in corner of building slab
They added water to the mix, while it was in the truck would be my guess.. It started to kick some, and the added water for workability.
Concrete contractor will never admit to it though :p
Anyway, just my assumptions based on the photo... And yes, stress reversal at the corners of a square pad due to shrinkage.
If we made our slabs on grade oval, this would be so bad.. :p
RE: cracks in corner of building slab