×
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

Slotted Hole Connection to Timber

Slotted Hole Connection to Timber

Slotted Hole Connection to Timber

(OP)
Hi,

I’m dealing with the following scenario and am wondering if anyone here has encountered something similar and can offer a bit of guidance.

I’m designing a cross-laminated timber balustrade that’s braced with steel angles.
The angles are bolted to WT brackets which have lag screws to the CLT.
Where the lag screws connect to the balustrade, the brace supplier has shown vertical slotted holes in the WT bracket.
I've attached the cutsheet detail for reference.

Strictly in terms of structural performance, it would be ok if the connection could slide a small amount; however, I want to limit deflection in the balustrade to protect finishes and prevent any uneasiness if someone pushes on it.

I’m wary of trying to restrict sliding by relying on a tight connection and friction between the lag and the bracket. Can I achieve enough resistance screwing into the CLT, or is there another approach I can consider? I've looked for references dealing with slotted hole connections to timber and am coming up short; does anyone know of a reference that could apply to this scenario?

Thanks.

RE: Slotted Hole Connection to Timber

I'm not sure I understand the need for slotted holes with lag screws.
Just set the assembly where you want it and pre-drill and screw in the lags.
No need for slots.

Might be that the fabricator "thinks" they need slots in case the "bolts" that they "think" are going to connect the assembly are fixed in place.

Check out Eng-Tips Forum's Policies here:
FAQ731-376: Eng-Tips.com Forum Policies

RE: Slotted Hole Connection to Timber

As JAE said.
Why lag screws? We always use self-tapping screws for wood. But I work in Europe.

RE: Slotted Hole Connection to Timber

(OP)
The slots are there so the contractor can temporarily secure the balustrade after it's lifted into place by a crane.
Some adjustment likely will be required later to get everything plumb.

RE: Slotted Hole Connection to Timber

Then do 1 or 2 slotted holes and 2 holes with tight fit to screw after adjustment is made.

RE: Slotted Hole Connection to Timber

If they want slotted holes they need to be in addition to the ones you specified. I would not rely on friction.

RE: Slotted Hole Connection to Timber

You might fab the brace as two lapped angles connected with slip critical bolts in slotted holes. Or pretensioned bolts if you're able to weld the finished product. Both of those paths embody cost of course. I suppose you could also field drill final set screws into the angles.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

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