Fabricator Designed Steel Connections

[STR04]

I have a conflict with a senior engineer in our office who states that all connections are designed by the fabricator. I cannot say that he's dead wrong but I look at Section 3 of the 2005 AISC Code of Standard Practice for Steel Buildings and Bridges and it really implies that this responsibility is on the engineer of record. How do others view this issue?

TIA

 

[Taro]

In the U.S., the standard practice for steel connection design varies by region. In the east, most connection design is delegated to the fabricator. In the west, all connections are designed by the Engineer of Record. The western practice stems from old Uniform Building Code seismic provisions.

 

[frv]

Taro is right.

I'm in the Texas- connections are detailed by fabricators (question of efficiency), but in any seismic area, the EOR details connections.

 

[ronster]

The engineer of record has some responsability even if the connections are designed by the fabricator. Typically the engineer will detail any unusual connections and indicate beam reactions on the structural drawings for the fabricator to design. The engineer reviews and approves connections on the steel shop drawings detailed by the fabricator. So you are both right. The engineer ultimately assumes responsability but often the design is done by the fabricator and checked by the engineer.

 

[JKW05]

I don't have the 2005 edition with me, but I believe the 2000 code of practice had a list of requirements that are to be provided (e.g. reactions, moments) if the designer is delegating the selection of connections to the fabricator.

 

[STR04]

Here is the document.

http://www.aisc.org/ContentManagement/ContentDisplay.cfm?ContentID=27714

 

[nutte]

STR04, there are many, many threads that discuss this issue in length. A search should pull up several.

frv, I would say that for west coast jobs, the EOR designs the connections, but this is not necessarily the case for all seismic jobs. I have seen projects in the midwest (New Madrid fault) with seismic connections assigned to the fabricator.

JKW05, neither the 2000 or 2005 code lists specifically what the EOR is required to provide if the connection design is delegated to the fabricator. It instead says something to the effect that the EOR shall provide the necessary information, which may include reactions, moments, etc, but not a solid checklist per se.

 

[rtmote]

In Northern Alberta I have seen it both ways. I am engineer of record and accept detail design by fabricators. I accept the responsibility for giving them the numbers for design and they accept the responsibility for design and details. They are seen as an extension of the project team. Of course I review their work and interact with them continuously. The responsibility overall lies with myself stamping the documents. This is faster, efficient and leads to good economies of time and costs as the fabricators has great experience and know what works well. Engineering time is minimised.

I have also done previously connection designs, which are then reviewed by the fabricators for detailing. This can be time-consuming and queried heavily; it is a design by the engineer that is dependent on the engineer's experience and may not reflect the preferred practice by the fabricator. I may have only designed tens of different kinds of connections, mostly moment-type, whereas the fabricator has thousands, of all kinds!

It matters the scale of work, deadlines, comfort factor in each other and the team work.

Robert Mote

http://www.motagg.com

 

[UcfSE]

I provide the design for standard connections. The only time I try to farm them out is for odd or special/congested connections or the like. I don't presume that I will come up with the best or most economical design in these cases so I provide a load and have the fabricator design what works best for them.

 

[Lion06]

We let the fabricator pick the connections that work best for them. Different shops have different preferences. We provide a beam reaction table to let them know the max reaction for each beam depth and they provide calcs and shops and we check teh calcs and coordinate the shops against the calcs.
We do design and document unusual connections.
Designing all of the connections can often be a waste of time if the fabricator comes back and asks to change all of your double angle connections to shear tabs. Now they are designing them and your design time was wasted.

 

[JKW05]

Section 3.1.2 says "When the fabricator is allowed to select or complete Connection details, the following information shall be provided in the structural Design Drawings....."; Four items are then listed.

If the C.o.S.P. is being used, I would interpret that as a requirement. It does not say it "may" include these items. It then goes on to say that the connection details are to be submitted to the "Owner's designated representative" for approval.