Rebars protruding the construction joint. 2

[inhyoks]

Hello all,

I need your advise. I have a situation that rebars for the mat are protruding the construction joint (at the base of the wall). There are wall dowels being fully developed per ACI, but the bar hooks from the mat is protruding through the construction joint by average 2".

What do you think about this?

 

[BAretired]

I think it is unacceptable.

BA

 

[TXStructural]

If the hook extensions were just an inch or two longer than required (unlikely), then there would be no real issue. But, if the hook is not properly embedded to develop the full, required strength, or the bars are misplaced, then there is an issue. There is a tolerance permitted on placement, and as long as the placement was in tolerance per ACI 117, they should proceed with construction. I do not think there will be any implications overall, with the exception of possible cracking adjacent to the joint, depending upon cover depth and other factors. That said, the joint is probably a cold joint for convenience of construction, rather than a joint intended to prevent cracking or allow movement. In such a case, I would not expect any trouble. Is there a key or intentional rough surface intended to prevent lateral movement of the wall relative to the mat? (in which case the protruding bar will just help with that function.)

 

[inhyoks]

BAretired and TXStructural, thank you for your reply. BAretired, could you give me some details why you think this is unacceptable?

 

[BAretired]

If the bars are projecting 2" above the construction joint because the bars were placed too high, placement is unacceptable. If the bars project because they were cut too long to fit below the joint, they may be acceptable if the projection is thoroughly cleaned of impurities or is not required to develop the bar in bond.

BA

 

[inhyoks]

BA,

Thank you for your response. The rebars are cut long to exceed the minimum development length. The shear friction load between the construction joint is taken by the dowels, but when the dowels yield, wouldn't the tips create a concentrating load to have potential concrete failures to the wall? This may occur during the extreme load case (i.e. seismic, blast load). What do you think?

 

[jayrod12]

If your dowels were to yield would you be that concerned about a little bit extra concrete damage that "may" happen?

I feel that there would be bigger issues if the wall ever saw loading that causes the dowels to yield that I would not be concerned about it.