×
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

Sag rod "double nutting"

Sag rod "double nutting"

Sag rod "double nutting"

(OP)
Girt Bracing
 
Question
08/01/2007

I am designing a building with vertical siding, channel girts, and sag rods. I was told that the industry standard is to consider the channel braced at the sag rods. How is this possible, since the sag rods are neither at the compression flange nor able to act in compression? Is this the appropriate way to look at bracing the channel, or is there a more appropriate method?
 
  
Answer(s)
The siding attached to the tension flange of the girt acts like a torsional brace. Unfortunately, it may be an ineffective brace in terms of restraining the compression flange of the girt, since it is attached to the tension flange. One needs to calculate the adequacy of such a brace using Appendix 6 (torsional bracing) in the 2005 AISC specification (a free download from www.aisc.org/2005spec).

Procedures in AISC Design Guide 7, Industrial Builidings—Roofs to Anchor Rods, 2nd edition, for the design of girts are outlined on pages 17 and 18 of the document (www.aisc.org/epubs). Note that item 6 mentions that the sag rod acting in conjunction with the siding should be designed to prevent the twist of the girt under suction loads in accordance with Chapter F of the AISC specification. As such, double nutting would be required to provide resistance to twisting.

This is from http://www.aisc.org/MSCTemplate.cfm?Section=Steel_Interchange2&Template=/CustomSource/Faq/SteelInterchange.cfm&FaqID=2779

My question: what is double nutting? How does it resist twisting?

 
 

RE: Sag rod "double nutting"

Double Nutting is when you put a nut on each side of the girt.

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