Concrete column against existing building

[doka1]

I work for a concrete contractor that is installing the foundations for an addition to an existing masonry bearing walls and timber beams building. We installed a small portion of wall and a 2'x2'x10' concrete column against the existing masonry without compressible filler or fiber expansion joint. I know it's not the best practice, but we are catching a lot of heat from the architect and general contractor about it. The architect claims that the concrete has bonded to the masonry and will compromise the masonry as it begins to shrink. I have attached pictures showing the two conditions.

The front of the column will have a brick veneer in front of it. The top 2' of the wall will be exposed. I feel I should cut a groove for sealant in the wall area to not allow water to get in between the new concrete and masonry.

On a scale of of 1-10 what would you all consider the severity level of this deficiency? (1 being not severe)

 

[doka1]

Additional photo

 

[CELinOttawa]

Are you in a seismic or high wind zone? If so this is more than just bad practice, and nothing you do short of rebuilding the masonry wall with a gap is going to preclude all the (many) problems with the bricks.

If seismic or high wind, you need the gap OR need to specifically design the new and modify the old for this condition. Loads will travel through any connection, and that is there effect created by pouring the column in contact with the bricks. I hope this is a simple veneer, as that will make your corrections much easier!

 

[doka1]

Nope, in nj.

 

[CELinOttawa]

Well I'll be very interested to follow this, but don't believe I can be of much help... Everywhere I've practice's this would be a major no-no due to seismicity, or is a very old detail which had been successful in order to still be around.

Good luck, I'm sure some members here will be able to help!

 

[Ron]

Bad idea! You have a very old, multi-wythe brick wall on a separate foundation from a multi-story steel and concrete framed building. These two should certainly be isolated from each other. Concrete shrinkage is only one issue you'll find to be a problem. Another is differential settlement of the two buildings (the old one is probably stable; however, it might be affected by the new building). In any case, the differential movement will cause cracking problems and induce stress in the brick wall, likely separating the wythes. That creates another problem....waterproofing. The column and the cast-in-place wall will likely cause cracking at their interface with the brick and allow water intrusion for the exposed areas. Because of the mortar joints in the existing wall, the cast concrete is now "keyed" into the wall, whether or not you have actual bond between the brick and the concrete.

As for this being a construction defect? Yes it is. If problems result from it, your company will likely bear the brunt of the criticism (and cost to correct)as this is a deviation from accepted practice.

This can still be corrected. It won't be easy, but the separation can be obtained. The wall will be more difficult than the column. You can probable get a concrete wire saw and do the column manually. The wall will require more thought and planning.

Good luck. Get it done before the lawyers get hold of it.

 

[ztengguy]

Does the new footing go below the exising footing? Is it on piles? Do you know the anticipated settlement for the footing?

What about story drift. Isnt NJ a high wind area, due to hurricanes.

I guess as the concrete sub, did you follow the drawings that (hopefully) an Engineer produced? What detail do they show? Why couldnt the steel column go down to the grade level?

Lots of issues here, I would be talking to the EOR about this and get his input.

 

[RHTPE]

Simply put, it's a bad condition. The wall and the column should be isolated from the preexisting masonry For all of the reasons stated above.

The only possible exception, and I highly doubt that it's sensible, would be if the column/wall were intended to be tied to the brick masonry wall.


Ralph
Structures Consulting
Northeast USA