×
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

Concentrated load applied to top flange of W-shape

Concentrated load applied to top flange of W-shape

Concentrated load applied to top flange of W-shape

(OP)
I'm considering ways to eliminate the resulting torsion from a 3 kip horizontal concentrated load applied to the top flange of a W-shape and would like some opinions.

The space between the flanges on one side of the beam have to remain clear of obstructions and a wide flange has to be used.  I'm also limited in size so I can't use a stout wide flange and just design for torsion.

What I'm considering is using a full depth stiffener on one side of the beam at the location of the concentrated load to transfer the load to the bottom flange, and then provide a strut on the bottom of the beam to transfer the load to another member.  

Feedback on this detail is appreciated as well as alternate solutions.

RE: Concentrated load applied to top flange of W-shape

What is the "other member"?  If you can provide a strut to "another member", why not use a HSS post with a depth to match bf/2 + 2" (or so).  Use a cap plate and the stiffener you talked about and weld the WF to the cap plate at the edge of the flange and near the web.  This will take the torsion directly into the HSS post.

RE: Concentrated load applied to top flange of W-shape

Can you add a beam transverse to the beam with the torsion, at the point of intersection of the column, that frames to another beam to take out the torsion?  

The connection of the two beams would have to be a moment connection, but this is the simplest way I can think of in doing it.

Mike McCann
MMC Engineering

RE: Concentrated load applied to top flange of W-shape

(OP)
StructuralEIT-
Unfortunately the post can't be added.

msquared48-
I can't add a transverse beam.   

RE: Concentrated load applied to top flange of W-shape

What kind of strut were you talking about?

RE: Concentrated load applied to top flange of W-shape

Can you weld a side plate on the WF (on the side you were going to add the stiffener)?  It would be parallel to the web, and be welded to the top and bottom flanges to create tube section.   

RE: Concentrated load applied to top flange of W-shape

Can you create a horizontal truss to transfer the lateral load?

RE: Concentrated load applied to top flange of W-shape

Anybody seeing any problem with his original concept? It sounds a way to go if the member supporting the strut is stiff enough. A quick sketch should gain better understanding.

RE: Concentrated load applied to top flange of W-shape

OK, then I agree with SEIT - create a tube section.

Mike McCann
MMC Engineering

RE: Concentrated load applied to top flange of W-shape

What is the WF supporting?  If there is a floor (or roof for that matter), why not add a drag strut at the location of the horizontal point load and take it into the diaphragm?

RE: Concentrated load applied to top flange of W-shape

Or...  what structural member is transferring the 3K lateral force to the top flange of the beam?  

Can this force be both tension and compression?

Mike McCann
MMC Engineering

RE: Concentrated load applied to top flange of W-shape

"What I'm considering is using a full depth stiffener on one side of the beam at the location of the concentrated load to transfer the load to the bottom flange, and then provide a strut on the bottom of the beam to transfer the load to another member."

This concept works if:
*  the strut and other member can sustain 3 kips force horizontally.
*  the strut is connected to the stiffener to resist a moment of 3k*depth of WF.

Without the moment connection, the concept does not work.

BA

RE: Concentrated load applied to top flange of W-shape

As he said; "Without the moment connection, the concept does not work."

RE: Concentrated load applied to top flange of W-shape

Are you still there CTW?

Can you post a sketch?

RE: Concentrated load applied to top flange of W-shape

I like option #2

RE: Concentrated load applied to top flange of W-shape

(OP)
I'm still here.  I had a busy day yesterday (and still today) and didn't have time to post until now.  I see there's a lot of questions and suggestions so hopefully the attached sketch can shed some light on the subject.  

The force is only applied in one direction.  

No members have been designed yet as I'm only trying to look at load paths at this point, but the beam is required to be a WF.

I considered plating one side of the beam to form a tube as StructuralEIT suggested, but then started to brainstorm alternate ways to do this.  

My thinking with the torsion is that since it's located at one point along the top flange, then the force could be transferred to a strut on the bottom flange.  

Keep in mind when viewing the sketch that no member can be located in between the flanges on the left side of the beam or the top of the beam.

RE: Concentrated load applied to top flange of W-shape

CTW,
The member on the bottom cannot be just a strut, which implies axial compression only.  It also has to develop the moment P*d where d = the depth of the WF.  If it can do that and if the other member to which it is attached is stiff enough, your detail should be adequate.

An angle stiffener with the outstanding leg away from the web would be stiffer than a plate.  Looks like the 'strut' should be deeper.

BA

RE: Concentrated load applied to top flange of W-shape

Can you get a WT in there or something else with a little more meat?  As BA says, it has to take the moment, Pd, and the axial force.  I would also want to make it pretty stiff to keep the top flange from trying to roll simply because of the lack of flexural stiffness of the "strut".

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