Cold-Form Components Connections 2

[jopalu]

I typically specify, in detail, every cold-form structural connection, with clip angles, tek screws, etc.

Recently, I had someone tell me that they specify, on the construction documents, that the cold-form supplier shall provide a cold-form submittal with detailed connections, to the architect and/or the engineer of record.

I am ok with this procedure for simple, interior partition walls. But, for structural connections, I am uncomfortable with leaving this up to the cold-form supplier.

Please advise ... Thank you!

 

[archeng59]

I agree with you. provide your own details. seems like whenever I leave that sort of thing to the supplier, I never get what I expected and end up arguing with the contractor about $$.

 

[STR04]

What if your dealing with CFS trusses...say the truss mfg'r is Alpine Trussteel who already has their own connections that fit its proprietary shape?

 

[UcfSE]

When I work as a specialty engineer for cold-formed steel contractors, I am glad they hired someone because the majority of what I see coming from the SEOR is incomplete and/or incorrect. This goes for big medium- and high-rises as well as single-story buildings.

It's good that you can be thorough enough to keep the stud connections and details in mind when you detail the rest of your structure as long as you take care of everything that needs to be addressed. If you allow the suppliers to provide engineering and/or details, be sure to have them submit shop drawings for review and include engineering calculations that are properly signed and sealed. This will weed out a lot of your concerns. Treat it like you would any other shop drawing requirement, giving them codes they have to use, material requirements, and any special loads or conditions they have to consider. Be sure to note any requirements for connections to accommodate deflections and how much, and put member deflection requirements either in your notes or in the building specs.

 

[samdamon]

Jopalu-

For the exterior facades of one and two story office/medical buildings we show typical light gauge stud sizes and spacings and typical connection details, while also asking the Contractor to submit signed and sealed calcs and shop drawings showing a final design. A specialty engineer hired by the Contractor uses the loads and deflection criteria we give in general notes in his work and submits the calcs and shops to our office as EOR to review.

We have done half dozen buildings this way. It has worked out ok on each project.

The advantage to the Owner in this arrangement is that the specialty eng and shop drwg detailer can provide a well detailed, finished light gauge design cheaper than our office, because they work with light gauge every day. For us to design and draw every light gauge condition and connection detail, even in a relatively simple building, would take an inordinate amount of time and is not cost effective imho. (It may be different in other parts of the country).

The only problems we've had with this approach are par for the course in any construction endeavor. For example one Owner resisted paying even the smaller fees for the specialty engineers light gauge design, and wanted to install a "design" provided by the G.C. We convinced him not to by pointing out in writing that he was personally taking responsibility for the engineering design of the facade.

In other instances we have had to fight to get the light gauge subs to actually follow the shops, and to a lesser degree have had some disagreements with light gauge detailers stuck in "We've always done it this way" land. Like I said, par for the course.

For the EOR its an advantage to go this way because a large portion of the work of getting a finished light gauge design can be done by others and is also downstream of the issue of 100% constr docs and the permit stage. As EOR you still control the design because everything gets reviewed on paper before a single stick goes up. Of course, you MUST work out the design in your own docs enough so that load paths, bracing etc are all taken care of.

Just for example, a recent 5,000 sf 2 story office bldg with a nothing-special facade had a pretty complete calc submittal from the specialty engineer of 52 pages and shop drwgs in tabloid format of 12 pages.

Hope this helps.

By the way, look into panelizing any substantial light gauge elements. Fabricating big pieces off site can save a lot of field headaches.

 

[DaveAtkins]

If you are capable, AND are being paid enough fee, by all means detail and design the cold formed steel connections. BUT...

I also act as a structural consultant to drywall contractors, and one advantage is that I can engineer and detail the exact connectors that the contractor uses. My clients build my fees into their contracts.

DaveAtkins

 

[jike]

For projects with minimal light gage, we will design and detail it. For larger projects, we write a performance spec. that requires the light gage contractor to hire a structural engineer to design, stamp and submit calcs and complete detailed drawings.

Our fees typically do not include enough money for us to design the light gage. Our competitors are also doing the same.