×
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

Diaphragm fasterners

Diaphragm fasterners

Diaphragm fasterners

(OP)
considering a flexible metal roof diaphragm in a two span condition, simply supported, how are the fasteners designed over the interior support?  

are they designed for 1/2wL for the joist spans on either side, and doubled up  on the supporting line?

RE: Diaphragm fasterners

Not sure what you are asking.  Fasteners of metal deck to supporting beams or joists are usually used primarily to resist lateral in-plane shear (diaphragm action) and vertical uplift due to wind.

Gravity loads are resisted by the bearing of the deck on the supporting member - that load doesn't usually go through or depend on the fasteners.

RE: Diaphragm fasterners

(OP)
perhaps, my question was poorly stated.

consider a long building with three braced frames, one at each end and one in the middle.

now with 300plf of lateral wind shear on one side of the interior braced frame and 300 plf of lateral wind shear on the other side, is the fastener spacing designed for 600plf over the interior braced frame?






RE: Diaphragm fasterners

I think you are asking if the total lateral shear to be resisted at a single interior support line in a flexible diphragm is 0.5*w*L, where L is the length of the building?

If so; then yes and you would have to provide a total number of fasteners to transfer the total shear to the interior wall (you are referring to this as "doubling up" the fasteners to take the shear at each side of the wall).

It is confusing because you refer to the "diaphragm" and also to "joist spans", not sure if you are asking about lateral or gravity.

RE: Diaphragm fasterners

You just beat me.

RE: Diaphragm fasterners

(OP)
thanks, haynewp,

silly question, i know, but i ask because i dont think ive ever seen anyone call out for 2x fastener spacing over an interior braced frame, but it came up recently.

RE: Diaphragm fasterners

Thanks Galambos for clearing that up.

haynewp - agree with you as well.  Good answer.

RE: Diaphragm fasterners

I have called them as "5/8 dia. puddle welds at 6" c/c, typ along the length of the interior support" or whatever it takes to get the total shear required to be transferred out of the diaphragm into the interior vertical element. Remember to include drags as needed.

RE: Diaphragm fasterners

I've always specified double lines as well.

RE: Diaphragm fasterners

Vulcraft's deck catalog, has Allowable Diaphragm Shear Strength tables that give allowable design values for shear transfer based on the deck's size, thickness, fastening, etc.

RE: Diaphragm fasterners

I understand what you are asking, and the answer is yes, the CONNECTION of the diaphragm to the interior braced frame (or moment frame, or shear wall) drag strut line must have twice the capacity of the DIAPHRAGM on each side of the drag strut line.  It is best to use the same fastening throughout, however, to keep things simple.

DaveAtkins

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