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Re: Post-tensioned slab on grade

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There is no need to heat the strand or anything before reanchoring it. In
fact, I would recommend against restressing strand that has been cut be
heating due to probable reduction in strength and also possible induced
brittleness which could cause failure during restressing.

Simply expose each strand for a length of approx 1 foot from the edge of
the proposed opening.

Strip off the plastic coating and degrease the strand thoroughly with a
solvent exposing the strand.

Cast an epoxy concrete anchor block around the exposed length.

Once it has fully set, Then cut the strand as you cut out the opening with
your saw.

This method works equally well for bonded (where it is a precaution against
incomplete grouting) or unbonded post-tensioning cables.


At 10:55 5/11/98 -0800, you wrote:
>We recently built an 8" thick post-tensioned slab on grade , with
>overall dimensions 120 by 90 feet. The active reinforcement is 1 strand
>with 1/2" dia. every 2 feet, in both directions and placed in the middle
>depth of the slab.
>Now the owner needs two openings of 3 by 8 feet along the edges of the
>slab.
>I am worried  about cutting the tendons to make room for these openings,
>because I'm not sure if the release of energy when I cut them may damage
>the slab. Does anyone have any suggestion ?
>
>
>Juan Carlos Gray
>
>
>

Regards  Gil Brock
Prestressed Concrete Design Consultants Pty. Ltd.
5 Cameron Street Beenleigh Qld 4207 Australia
Ph +61 7 3807 8022		Fax +61 7 3807 8422
email:	gil(--nospam--at)rapt.pcdc.com.au