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RE: PT Construction

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Is the problem with the inspection or with the lack of construction knowledge on the part of the contractor, or both?
 
Thanks
 
Arvel
-----Original Message-----
From: GSKWY(--nospam--at)aol.com [mailto:GSKWY(--nospam--at)aol.com]
Sent: Monday, May 02, 2005 9:23 AM
To: seaint(--nospam--at)seaint.org
Subject: Re: PT Construction

In a message dated 5/2/2005 10:11:13 AM Eastern Daylight Time, GSKWY(--nospam--at)aol.com writes:
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 removed.
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.
 
Gail Kelley