Horizontal cracks in column under ramp

[arawinda]

Picture shows horizontal crack runs along the column just under the ramp at 3rd and 4th levels of structure. Still the building is under construction and just completed 4th level slab/ramp concreting. Foundation is a piling system rest on bed rock. Anybody can explain what are the reasons for this please..?

 

[TehMightyEngineer]

The potato used to take this picture has a pretty poor resolution, I can't even see a crack.

Maine Professional and Structural Engineer
American Concrete Industries

http://www.americanconcrete.com

 

[jayrod12]

I think it's along the horizontal edge of the formwork.

I wouldn't be surprised if it's just bleed water spalling off or something like that. But it's tough to tell on the picture.

 

[hokie66]

Like the others, I don't see a crack.

 

[arawinda]

Sorry for poor quality photo. Please find closely taken pics here...

 

[arawinda]

Here is another closely taken pic....

 

[hokie66]

Still hard to tell if they are cracks or just indicate roughness of the formwork or similar. If they are indeed cracks, the most common causes near the tops of columns are overly exuberant removal of forms, and plastic settlement due to inadequate compaction.

 

[jayrod12]

From the first picture the column in general appears to have been vibrated sufficiently, at least for the majority of the height. They may have gotten lazy at the top of the column but that seems unlikely.

Removal of the formwork above the crack would likely aid the discussion.

 

[Canuck67]

Difficult to tell from the photos, but looks like it may be a cold joint. Inadequate vibration during placement combined with a time lag between successive layers of concrete being placed in the column/wall. Early removal of forms could have also contributed.

 

[Guastavino]

Looks like a cold joint to me