To a certain extent the paranoia about drilling into PT slabs has really been a diservice to everyone.
Unless it is a complicated tendon layout, an engineer who knows what they are doing should be able to tell the owner whether or not they can drill in a certain point.
For a higher comfort level, they can use GPR or X-ray. I personally have not seen anyone be able to locate anything with great skill using a cover meter, even some of the new fancy ones that use neural network progamming logic.
With respect to the damage to tendon damage, the biggest problem is with core drilling and pavement breakers (60 or 80 lb hammers.) With hand-held rotary drills, at least the smaller ones, you will at most put a little ding in one wire. Kind of like if you hit a coat hanger with something pointed.
If someone is using an 18 pound chipping hammer, they should know when they have hit the sheathing (unless they are really, really slow on the uptake.) They should never get to the strand.
With an electric chipping hammer, it is hard to do much damage to anything, including the concrete you are trying to chip out.
Sent: Tue, 27 Sep 2005 20:12:58 EDT
Subject: Bar Stools on the move
Hello all another question:
The hotel building has a 12' thk PT slab. They want install bar stools for a new bar area.
The owner is paranoid about his slab and will not allow drilled in bolts. The owner wants to put steel plate on the floor and attach the stools to the plate. Glue the plate to the slab only.
This is for 45 bar stools all in a row.
I suppose you could use 1' plate and make it wide enough so the patron would not fall over due to you occasional bar room brawl.
I upset my architect client why I told him to find another engineer, but I told him I would look into it.
Have any of you ever done such a thing as this.
Johnson & Nielsen Associates
Palm Springs, CA