Coreing Hols in One-Way Slab

[Lesali]

As a solo engineer I appreciate this site immensely and today I need some advise on a contractor's idea.
He wants to completely chip way the concrete over a 10"x48" area against the wall of a parking garage floor to reveal the steel in the floor. After identifying the steel that can be cut and permanent penetrations are sleeved, he proposes to patch it back with high strength cementatous grout.

The details: I have a telecom project where we want to run numerous 1.6" conduit thru a 9" one-way slab of a parking garage. The plan was to core (8) 4" holes against a "non-bearing" wall where the slab ties in. By inspecting the original drawings, I tried to detail for the contractor the type and location of existing steel. I identified the type of steel that could be cut (temp steel) and that which could not be cut (bending and slab dowels to the wall). The contractor after X-raying the slab could not distinguish between the types of reinforcing and is suggesting the above.

Is this a feasible repair? If so would anyone recommend using a bonding agent?
If not, perhaps I could just put in knee braces against the wall to support this span and let them hack away at even the strength steel.

 

[Ron]

Get someone who knows what they are doing to interpret the radiographs. I've seen this many times where the radiography was done and the results showed images, but those interpreting the images didn't know anything about reinforced concrete.

For your purposes, you only need to miss the reinforcing for coring...that's not difficult.

 

[TDIengineer]

You said that the wall is at the non-bearing or parallel edge of your 1-way slab. I am assuming then that the dowels are for shear transfer of lateral loads from the diaphragm to the wall as well as for out-of plane loads?

Maybe you can justify that the diaphragm connection is ok if a bar or 2 is cut. I assume it is 10" away from the wall, but 48" long along the wall? If dowels are at 18", maybe 2 will be cut?

You could then add back additional post installed anchors from the underside with a clip angle if you were really concerned about shear transfer and the out-of-plane wall connection.

Another option in case you don't get anywhere when you suggest they aren't reading the x-ray results properly. Was this done by a testing lab? Or did the contractor have his cousing check it..