Steel detailing - Pass Through Forces

[macan1]

I have to design connection details for X-braces connected to beams and columns.
Member sizes, Tension and Compression brace-forces are given.
Can someone suggest where I can find references (link, codes etc.) for pass through forces through the joint, how do we design it etc.

 

[abusementpark]

The AISC Steel Manual. I forget the exact pages, but it is under the bracing section. They give their recommended method and all the force assumptions associated with it.

Google "Uniform Force Method" and "Whitmore Section" and you should find some helpful resources. You can look at the companion disk to the AISC manual and it has some solved example problems for bracing connections.

 

[connectegr]

The "transfer forces" must be provided by the EOR. Dr. Thornton use to present a connection lecture, which gave examples of several estimates of connection transfer forces, based on the given brace load only. He determine several posibilities for the beam transfer force, which where both conservative and overly liberal. This information is within the EOR's analysis model. This transfer force is not the same as Hb for the UFM brace calculation. And it is not the internal axial force in the beam.

http://www.FerrellEngineering.com

 

[slickdeals]

@connectegr,
Do you happen to have a copy of that presentation on transfer forces? If so, could you please email it to me?

It’s no trick to get the answers when you have all the data. The trick is to get the answers when you only have half the data and half that is wrong and you don’t know which half - LORD KELVIN

 

[connectegr]

I don't have a copy. I think it was called Economical Connection Design. It may be available on AISC website. It think there was also a MSC article, about the tranfer force estimates. I will see Bill next week and ask him.

http://www.FerrellEngineering.com

 

[WillisV]

Tranfer forces, in particular how to calculate them (you cannot just output them from an analysis program) and even more so how to present them to the connection engineer if that is the route you take are in my opinion one of the least understood aspects of standard steel building design.

As connectegr stated Bill Thornton has a good general discourse on the subject which was published in EJ:

http://www.aisc.org/store/p-893-connections-art-science-and-information-in-the-quest-for.aspx

Bo Doswell also wrote a more recent EJ article on the subject that gets a bit more into the technical aspects:

http://www.aisc.org/store/p-2032-transfer-forces-in-steel-structures.aspx

As far as presenting them to the connection engineer, the appendix to the forthcoming (as yet unpublished) AISC Design Guide on Braced Connection Design gives some guidance as far as how to distill the number of load cases down to a few reasonable cases to present. Hopefully that will come out within the year.