×
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

Effect of column forces in designing column-beam connection
3

Effect of column forces in designing column-beam connection

Effect of column forces in designing column-beam connection

(OP)
As structural engineers, we normally provide the connection forces (moment, shear and axial forces) from a beam for MC connection between a column and a beam. The forces from the column (moment, shear and axial) are not provided. However, as per AISC design guideline 13, the column shear will affect the panel zone shear capacity. I have not found an example which includes column forces (shear, moment and axial) in designing MC connection between column and beam.

My questions are:
1.Should column forces be included in the column and beams connection design? Is there anyone who has such experience or knows any reference?

2. What will steel detailer do if no column forces are provided? Will he assume some value for column shear in design the connection?

3. If column forces are provided, what will detailers do with combination of forces from column and beams?

Any comments and suggestion will help me a lot. Thanks.
 

RE: Effect of column forces in designing column-beam connection

The problem never occurred on my watch, we designed all major connections and showed them on the design drawings. We only left the routine connections to the detailer.

The problem with trying to transmit complex loadings is that there are several cases to cover. Designing the connections provides another layer of thought about the fitness of the members, it often becomes clear that a different member would make the connection design so much better.
 

Michael.
Timing has a lot to do with the outcome of a rain dance.

RE: Effect of column forces in designing column-beam connection

(OP)
Thanks for comments. Paddingtongreen,
When you design major connection and check panel shear, do you consider the shear and tension from column? Have you see any calculation include shear from column?

Thank you very much for help.

RE: Effect of column forces in designing column-beam connection

Newlearner, isn't there a senior engineer in the office to run these queries past?  These are fundamental questions and while you're ignorance is understandable from a lack of experience, surely you have someone overseeing your work???  If I was you I'd be concerned about the lack of education being provided by your employer.  

Sorry don't mean to be harsh.

 

RE: Effect of column forces in designing column-beam connection

pwht1 - newlearner maybe in the position myself and several of my associates found ourselves in at the beginning of our careers, there is no senior engineer to ask.

You need to look in the AISC code of standard practice, it requires that all the forces necessary to complete the design of the connection are shown on the drawings.  

Typically, I will spec the stiffener and doubler plates at my columns if they are needed.  The detailer will not check if these are required, because he is just designing the connection not the actually members.  During your design you make pick a heavier column just to avoid having to provide stiffeners or doublers.  The column shear, moment, and axial forces are the engineer's to design for.

The code of Standard Practice only allows for the design of Connections.  The definition in the code for connections makes me think that doubler plates and stiffeners are not connections because they do not actually transfer the forces between the members. They just reinforce a section.

RE: Effect of column forces in designing column-beam connection

(OP)
Hi ash060. Your comments are very helpful. Thanks a lot.
  

RE: Effect of column forces in designing column-beam connection

(OP)
Hello ash060. You mentioned that AISC code of practice has requirement for forces to complete the connection design. Is it possible for you to provide which document and chapter? Sorry I am not so familiar with American code. Thank you very much.

RE: Effect of column forces in designing column-beam connection

Ash, must've been stressful.  I'm surprised your/employers insurers didn't complain or terminate the contract.  Could I have a list from you and your associates of all the projects you've worked on so I know where not to go :P

Newlearner, I'm not sure what the common practice is in the US/Canada but why don't you design and detail all the connections?  I'm based in Australia and here the structural engineer is responsible for all connections.  Even if the shop detailer does a connection we don't show, we still have to review and approve it or we (not the detailer) will face litigation if something every goes wrong.  

RE: Effect of column forces in designing column-beam connection

I have attached a link to the AISC website that contains the spec and the code of standard practice.  They are both free to download.

http://www.aisc.org/content.aspx?id=2884

RE: Effect of column forces in designing column-beam connection

I apologize the comment was meant as a joke but it wasn't very helpful.

I'm still curious though as to why you don't specify the connections yourself?

RE: Effect of column forces in designing column-beam connection

(OP)
Thanks you very much for help, comments and additional information.  

RE: Effect of column forces in designing column-beam connection

pwht1,
In America it is common for a specialist connection engineers to design the connection on behalf of the fabrication company. Connectegr from  http://www.FerrellEngineering.com  is one such person, he may drop byand give a full rundown. This hasn't caught on in Australia yet, With most engineers having to both the design for the structure and connections.
 

A clear conscience is usually the sign of a bad memory

RE: Effect of column forces in designing column-beam connection

Thanks Rowingengineer.   

RE: Effect of column forces in designing column-beam connection

Guys,

The way to really answer this question is to sit down with a senior engineer, in-house or external, and have a discussion about LOAD PATH at a beam-column moment connection.

Then you'll understand why some "spreadsheets do not contain these values"...

tg

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