×
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

Beams with Torsion

Beams with Torsion

Beams with Torsion

(OP)
Can anyone suggest a reference for design of structural tubes for flexure and torsion?

RE: Beams with Torsion

AISC Design Guide 9 - Torsional Analysis of Structural Steel Members
 

RC
All that is necessary for the triumph of evil is that good men do nothing.
    Edmund Burke

 

RE: Beams with Torsion

(OP)
Does that include torsion on steel tubes or is it for W shapes only?

That's the real basis of my question.
 

RE: Beams with Torsion

Section 4.4 - goes through the torsional stress on a closed shape.
Section 4.6.2 - goes through the combined stresses from torsion and other loads on a closed shape.

There are also a few design examples.
Example 5.2 does what you are looking for I believe.

RC
All that is necessary for the triumph of evil is that good men do nothing.
    Edmund Burke

 

RE: Beams with Torsion

(OP)
Thank you.

RE: Beams with Torsion

You can actually use the specification itself for this. I don't have it in front of me, but it's relatively straightforward. And as you must also check the combined torsion, flexure and shear.

RE: Beams with Torsion

Brezler, Lin and Scalzi "Design of Steel Structures"
contains extensive information on torsion of tubular structures.

Its an old book, but quite good in my opinion.

RE: Beams with Torsion

Your question is a basic strength of material problem.

RE: Beams with Torsion

chicopee-

What exactly is the purpose of your comment?

It is arrogant and not the least bit helpful. True as it may be, it seems the only purpose is to make yourself look informed at the expense of the OP.

And torsion, in general, is NOT an easy problem. In tubular sections, it is fairly straightforward, but for almost any other shape it is quite involved.

Structural engineers have the added burden of taking many other factors into account. Is the section torsionally restrained? Is it compact? Is there additional loading perpendicular to the cross section? In both directions?

You mechanical's may be able to design a circular shaft to transfer torque and forget about it. We don't have that luxury.

RE: Beams with Torsion

(OP)
Chicopee, your answer demonstrates that is that a little knowledge is a dangerous thing.

   

RE: Beams with Torsion

Most structural engineers would tend to agree with frv and try to avoid torsion if at all possible.  Sometimes that may not be possible so we seek a reference to help us out.

With torsion some strength of materials books dont have exactly what we need so we seek a bit more as the Op is doing.

Perfectly understandable.

  

RE: Beams with Torsion

(OP)
I have a very interesting residence with a number of curved beams that are loaded on one side only.  For example, I have a curved beam with a 32' span with a 2' offset to the side at midspan.  There is a roof that cantilevers out from 6' to 8' on the outside of the beam with no structure on the other side.

This one is going to be fun.  But it's going to require some study on my part.

And I'd certainly avoid torsion if I could.
 

RE: Beams with Torsion

I am still holding by my statement; however in fairness to the person who asked the question AISC has excellent reference material eventho to be able to use their naterial,it will require mental toughness as with any code reading.

RE: Beams with Torsion

TCSE

May not be easy to get the reference Brezler Lin Scalzi "Design of Steel structures"  but parts are really advanced strength of materials and theory is derived from first principles.  I did use it on a number of occasions for torsion problems (fortunately for me not many)and it got me out of trouble.

I think it may be worth having a look at it if you can locate a copy.

RE: Beams with Torsion

(OP)
Thanks Civeng80.  At worst I'll be able to borrow it from a University library.
 

RE: Beams with Torsion

Rather than start a new thread on beam torsion, I thought I'd follow with a similar request to this one. I've recently been asked to look at allowable twist in pre-stressed concrete I girders. I've gone through a couple of first principle derivations of possible strain states, but end up with unrealistic results.

I would appreciate it if anyone could point to some texts/papers/methods for evaluating the angle of twist at which cracking occurs.

RE: Beams with Torsion

torsion on closed sections is normally mainly a matter of addditional shear stress. Warping is negligible and axial forces are smal so both are generally ignored.


Any classical design textbook will give you a formula to calcualate the shear.

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