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Re: post tension slab on grade

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Has the slab been tensioned yet?  If so, you can't remove a portion and make it thicker without taking out large life insurance policies on your workers.  Also, make sure you know where the cables are *before* the laborer starts drilling the anchorage hole. You'd be amazed as to how far pieces of steel and concrete can fly when a PT cable breaks.
Is the problem that you don't have enough mass to resist uplift forces, or enough thickness for embedment depth?
If the problem is embedment depth, I don't think you have a problem.  The maximum allowable capacity of a HD5A is 3980 lbs (attached to a 5.5" post), and you can get that from either a 5/8" or a 3/4" dia. threaded rod with less than 10" embedment.
If the problem is not enough mass, and the slab has *NOT* be tensioned, you can chip out a section of the slab and footing, dig a big hole, and re-pour it.  You'll need to be very careful to not nick the cables, and you'll need to dowel into the slab around the perimeter.  If it has been already been tensioned, I can't think of anything right now.
Jason W. Kilgore, P.E. (MO)
Leigh & O'Kane, L.L.C.
(816) 444-3144
-----Original Message-----
From: D.A. [mailto:dnae(--nospam--at)]
Sent: Monday, March 26, 2001 7:44 PM
To: seaint(--nospam--at)
Subject: post tension slab on grade

I have job with existing post tension slab on grade
5" thick and where a shear wall is 8"  wide x 10" thick scope footing
at the edges is 12" wide x 18" thick
my question is I need to install HD5A in the scope footing but the depth is only 10"
which is not enough
any idea how to do that
thanks in advance