×
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

Does adding a force on top of stressed cable, in its free portion, adds to the initial stress
4

Does adding a force on top of stressed cable, in its free portion, adds to the initial stress

Does adding a force on top of stressed cable, in its free portion, adds to the initial stress

(OP)

A cable is stressed between two points, A on its first end, and B near its second end, by a force of 100KN, and a free portion near B remains without stress.

Please refer to attached image: Cable stressed before adding another force


Now B holds this 100KN by simply holding a lock attached on its cable. So if the cable is moved even by 1mm, this support vanishes.

Then the free end C is pushed with a force of 20KN. Now does force moves the cable away from its support at B, so the 100KN disappears? or does it adds to the 100KN to become a 120KN stress?

RE: Does adding a force on top of stressed cable, in its free portion, adds to the initial stress

If I've understood you correctly, AB load remains 100kN; BC load is 20kN. Reaction at B is 80kN on the slab and 20kN by the pull force from C.

RE: Does adding a force on top of stressed cable, in its free portion, adds to the initial stress

the reaction in B (on the support) is 80 kN but on the cable remain 100 kN

RE: Does adding a force on top of stressed cable, in its free portion, adds to the initial stress

Steve and Roy are correct, IF the the strand remains locked off at B. However, you mention it moving. If the strand is allowed to slip through the anchor, the prestress force will be reduced according to the decrease in strain of the strand.

RE: Does adding a force on top of stressed cable, in its free portion, adds to the initial stress

I believe that you will have that movement after your force C will be larger than 100. The prestress force will always be min. 100 (100+ force C) as long as the cable wont be "released".

RE: Does adding a force on top of stressed cable, in its free portion, adds to the initial stress

And this is the premise of 'couplings' (intermediate stressing) with post-tensioning tendons.

Neglecting friction (and other losses), at a magnitude of 100 kN in segment BC there will be "lift-off" at anchorage B, and uniform tension of 100 kN throughout A to C.

RE: Does adding a force on top of stressed cable, in its free portion, adds to the initial stress

Ingenuity is right, and it seems that my english is getting rusty.

- if F2 is 20, A-B stays 100, B-C is 20 and anchor force is 80
- if F2 is 100, A-B stays 100, B-C is 100 and anchor force is 0
- if F2 is 120, A-B is 120, B-C is 120 and anchor force is 0

Of course neglecting friction (and other losses)....

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! Already a Member? Login


Resources

White Paper - Implementing a Multi-Domain System
IoT systems are multi-domain designs that often require AMS, Digital, RF, photonics and MEMS elements within the system. Tanner EDA provides an integrated, top-down design flow for IoT design that supports all these design domains. Learn more about key solutions that the Tanner design flow offers for successful IoT system design and verification. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close