×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Heat curing: tendons cut

Heat curing: tendons cut

Heat curing: tendons cut

(OP)
When heat curing prestressed concrete products (slabs, panels etc), have the tendons to be cut immediately after the heat application or is it necessary to delay the cutting procedure until the concrete is cooled down?

RE: Heat curing: tendons cut

Fundamentally it makes little or no difference. You can argue either side of the thermal issues that can result.  You are less likely to spall the concrete at the cut (assuming flame cutting)if the concrete is dry (flame cutting will superheat the moisture in concrete and blow out if heat is directly applied to the concrete face).

RE: Heat curing: tendons cut

(OP)
Thanks Ron.
My concern was about shrinkage and possible residual tension rising during the cooling period, so I presumed it was better to cut tendons immediately after the heat application and leave concrete (and tendons) to shrink without any constraints applied.
 

RE: Heat curing: tendons cut

The coefficient of linear expansion for concrete and steel are essentially the same so change in temperature will not create any loss or gain to the prestressing force.  This is one of the reasons that reinforced concrete works so well. The main consideration for when the strand is cut is the required initial concrete strength required for the bonding of the strand.

Shrinkage is not an issue.  There will be no residual tension because this is a "prestressed" member.  The worst you could get if the coefficients were different would be a very slight loss in perstressing force.  The elongation to stress the strand is magnitudes greater than the thermal contraction due to a change of 100 degrees max.
 

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources