In a message dated 5/2/2005 10:11:13 AM Eastern Daylight Time,
Unfortunately, this is really not a standard way of doing
things and people got confused. One tendon didn't get stressed at all;
but since the wedges had been hand-seated, the tendons got cut off.
The beam cracked all to hell within about 10 minutes after the shoring was
Actually, this was a monostrand installation - all
nine of the tendons in one beam didn't get stressed.
If it were just one tendon, probably no one would have
noticed. In doing evaluations, I have seen two or three
of the tendons in a nine-tendon beam be broken or cut, without and
visible signs of distress (no cracking or excessive deflections.)
In this case, the cracking was pretty dramatic.
Problems with getting the beams stressed has pretty much make grouted PT
construction a non-viable option for parking garages in this
country. The beam tendons in grouted one-way slab and
beam construction are multi-strand tendons which require a special jack.
Usually, the stressing is done by the p-t supplier, and there are always
problems with getting them out to the site in a timely fashion.
In other countries, where it is standard construction, grouted PT
works fine. Grouted pt works fine in bridges, too, except the
presentations I have seen on the new cable-stay bridge in Boston were not
confidence-inspiring, as far as the quality of the inspection on construction
of the deck.