Question about connection design responsibility

[drusnar]

Hi all, I'm new to this forum and had a question about connection design and fabrication. I am currently working on a project and am unsure about how to show the connection design on the drawings. I've seen both ways from my brief experience. I've seen drawings that just say "Standard AISC A325 Bolted Connection" with a typical bolted detail and I've seen drawings that detail several different connections, with similar sized beams.

I think this is the difference between giving the fabricator a standard detail (with or without reactions) and giving them details for every unique connection in the structure. Giving detailed connections for many connections can create a lot more details.

I'm curious what other people do and what pros and cons there are to both?
In my particular case there won't be just one typical bracing connection (vert and horz). There could be several depending on members sizes, loading, etc

Thanks

 

[jike]

It depends on exactly what part of the US that the project is in. Also, will the project be using a qualified fabricator or will it be fabricated by maintenance workers who are not familiar with "standard connections".

 

[DCBII]

The AISC code of standard practice section 3.1.2 (p 16.3-10 of 14th Edition steel manual) offers 3 ways to go about it as follows:

Option 1- The complete connection shall be shown on the drawings.
Option 2- The connections shall be selected or completed by an experience steel detailer.
Option 3- The connection shall be designed by a licensed professional working for the steel fabricator.

If Option 2 or 3 are selected the code of standard practice provides detailed guidelines as to what needs to be on the drawings to aid the person designing the connections.

Personally I use all 3 options. I use Option 1 for difficult connections such as those in AISC 341 & 358 (seismic connections), base plates, and roof trusses. I use Option 2 for simple things that can be pulled out of a standard connection table in the AISC manual, and for things that I can put in a schedule in the drawings. I use Option 3 for connections that are not tabulated, but are not terribly difficult either.

There's some judgement involved too. On overseas projects in developing countries where I'm worried about technical expertise, I usually design more of the connections myself and delegate less. Also, fabricators in the Eastern U.S. seem to be more willing to do connection design than those in the Western U.S. I think this is because the Western U.S. is highly seismic and requires special detailing.

Even when you let someone else detail them, you should always do at least a cursory review the shop drawings details to make sure they understood the intent of your design.

 

[Brad805]

The AISC website has a good webinar on the topic of connection responsibility. Someone posted a link not too many months ago.