×
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

Steel Joist Girder Connection at Existing Tilt Panel Wall

Steel Joist Girder Connection at Existing Tilt Panel Wall

Steel Joist Girder Connection at Existing Tilt Panel Wall

(OP)
I have a situation where a joist girder sits on a WT that is welded to embed on an existing tilt panel wall. Does the embed take only shear? My senior engineer says since everything is attached, the deck, the joist are in place the connection will only take shear. I feel that the joist girder load will cause an eccentric load on the WT and therefore induce moment on the embed. We are planning to increase the capacity of the floor deck for the building and the general loading will increase by 10 psf. If I account for eccentric load the existing embed fails. If the connection is pure shear it is ok. If I need to design for moment, how should I tackle the problem?

RE: Steel Joist Girder Connection at Existing Tilt Panel Wall

I guess I'd see that there is eccentricity unless the joist girder seat and the WT work together adequately for the bending.

Usually the weld from the seat to the WT isn't enough to deal with the moment there.
Either there is moment in the joist girder seat/WT assembly or there is moment on the WT-to-wall connection.
You can't ignore both.

RE: Steel Joist Girder Connection at Existing Tilt Panel Wall

(OP)
The actual studs attached to the embed are fine in shear,tension and interaction. However, the embed itself is relatively thin. I need it to be 3/4" thick it is 1/2" thick. If I ignore the tension, the plate is fine.

RE: Steel Joist Girder Connection at Existing Tilt Panel Wall

Did you see the replies to this: http://www.eng-tips.com/viewthread.cfm?qid=363202

Dont ignore load that is there. If you boss insists you do, find a new boss.

now, have you checked to see if there is any live load reduction you can take, that was not taken before?

RE: Steel Joist Girder Connection at Existing Tilt Panel Wall

This has more to do with stiffness than anything else... If your girder and beam are effectively rigid, and your WT will not rotate, then you MAY have a case for shear only.

This is so rare that many codes make it illegal. In NZ3404 you MUST include a nominal eccentricity.

If you are in seismic zone, this argument is moot as well.

If you see high winds, I'd never consider this argument.

Effectively this is an abuse of St. Venant's principle. Local effects and Global effects at least INTERACT in almost every situation.

Don't design this to be dependent on no e, you'll be in for trouble IMHO.

RE: Steel Joist Girder Connection at Existing Tilt Panel Wall

The eccentricity needs to be considered. It's there. How old is the building? Based on ASCE standards for renovations of existing buildings, you may be permitted to assume an increase in f'c. If your loads are close, that may get you there.

RE: Steel Joist Girder Connection at Existing Tilt Panel Wall

(OP)
Ztengguy, I read through the various post and I believe there is eccentricity. The eccentricity I assumed was half the bearing length of the girder. I have reduced the live loads.

The building is a non seismic 90 mph wind zone. It was built in 2009. The concrete and studs are fine, I am more concerned about the thickness of the embed. How can I increase the thickness of the embed? I don't think it is possible.

RE: Steel Joist Girder Connection at Existing Tilt Panel Wall

You can through- fasten the plate to a far side (exterior) plate, if visually acceptable.

RE: Steel Joist Girder Connection at Existing Tilt Panel Wall

Can you weld some stiffeners onto the plate beside the WT section to stiffen the plate and take the load?

RE: Steel Joist Girder Connection at Existing Tilt Panel Wall

You can weld plates with post-installed anchors to existing embed plate as necessary to increase capacity.

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