×
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

Max. number of spans for a PT beam

Max. number of spans for a PT beam

Max. number of spans for a PT beam

(OP)
Is there a maximun number of spans for a beam to be post tensioned?
Thanks

RE: Max. number of spans for a PT beam

The length of tendons is the deciding factor, not the number of spans.  Over a certain length, losses start to become a problem.

RE: Max. number of spans for a PT beam

What kind of structure is it? In segmental bridge industry, having eight to nine span continuous is common.

271828 is right, but this can be overcome by adding adequate number of tendons.

RE: Max. number of spans for a PT beam

(OP)
It is a 4 storey parking building with 3-60' long beams.

RE: Max. number of spans for a PT beam

60' is not long. Should be possible to stress from one end if that is an advantage.

RE: Max. number of spans for a PT beam

(OP)
I am sorry, the beams are continuous beams with 3-60' spans. The total length for each beam is 180'.

RE: Max. number of spans for a PT beam

180' is about 55m. This is not excessive. Depending on the profile still could be stressed from one end, but I expect will be designed for stressing both ends.

RE: Max. number of spans for a PT beam

That is OK.  It is common to stress structures 180' long.  But remember to consider any restraints you have to slab shortening, mostly from concrete shrinkage, with an added component from your stressing.  

RE: Max. number of spans for a PT beam

This has to be modeled as hinge-pin-pin support. Over 180' length, deformation due to creep, shrinkage and temp. tend to be significant.

Why do you want a post tensioned system? Three indivisual pretensioned sections doesn't work?

RE: Max. number of spans for a PT beam

(OP)
Thanks all for your inputs.
Shin25:
This is a design build project. The contractor is looking at different options and off course, minimizing the cost. Cost of transportation is a considerable factor.

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