EOR's responsibility relative to light gage steel detailing

[JAE]

Typically with structural engineering designs/drawings/specs the engineer of record (EOR) can either:
1. Only show general light gage steel framing layouts, configurations, and perhaps a few stud sizes, etc. and leave the actual detailing to a delegated engineer to do connection designs, etc. and submit shop drawings to that effect.

2. Show a complete series of typical details, screw connection requirements, clips, and specifications that allow a contractor to build the light gage elements but no outside delegated engineering is used and no specific light gage shop drawings are provided.

3. Detail everything on the EOR drawings.


What do you typically do on your own plans with respect to light gage steel framing?
How does what you do depend on complexity of the light gage framing, location of the project, etc.?

Thanks.

 

[JAE]

I might add that I'm primarily concerned with framing such as stud walls, misc. overhangs, ceiling coffers, etc. and not full blown pre-manufactured light gage truss systems.

I realize that for LG trusses that is a pre-manufactured and separately engineered item.

 

[msquared48]

Usually, the light gage steel manufacturer has typical details that are in their catalog - what I would consider to be standard practice similar to the wood framing industry.

As a general rule, I design and detail anything outside of that norm.


Mike McCann
MMC Engineering

 

[XR250]

As light gage steel shop drawing is about 25% of my business, here is what I typically get:

The EOR has (sometimes) a fundamental understanding of the light gage steel and it capabilities, but often times does not provide adequate structure to attach to or to limit the spans of the light gage to within reasonable spans. (Just had an EOR want me to span a 30 ft. opening with a light gage header). This is a real problem as the EOR won't own up to it and the metal stud sub has already bid the job so it is his (and thus, my) problem. Most EOR's do not seem to be as prudent as the folks in this forum.

What should happen is that the EOR should sub out the metal stud shop drawings to a knowledgeable engineer who can provide the detailing and coordinate the structural steel with the light gage. Then, all the subs are bidding on a consistent set of drawings and do not have to guess what gages and other goofy details are going to be req'd. They also do not have to pad their bid with unknown engineering fees. The final cost of the job to the owner would likely be less.

Wishful thinking :>

 

[hawkaz]

As most of my light gage work is done in high seismic areas, I size and detail everything on my plans.

Then I issue SK details when it is built differently because nobody (except the inspector) looked at the plans.

 

[XR250]

@hawkaz;

Yea, I am lucky if 50% of the details I show get built correctly. I always have to keep that in mind when designing the details. If it needs 2 screws, I show 4 etc.

 

[msquared48]

The SSMA has a Produce Technical Information manual that has a few standard details in the back. My copy is from 2001.

I specify all the minimum structural properties for all the structural sections in my Structural Notes section too.

Mike McCann
MMC Engineering

 

[TDIengineer]

For hospital design in California the exterior framing system must be entirely detailed on the drawings. Stud size, spacing, connections, wall sections, all detailed. We may get shop drawing that re-iterate the approved details but the light gauge framer has to follow the details on the drawing or a change order has to be issued to deviate from the plans.


For commercial design in California, I usually see the exterior metal stud framing as a deferred item. General wall sections are provided by the engineer and architect showing drift joints, drift clips etc... The specifications indicate design criteria and that shop drawings are to be issued stamped and signed by a licensed PE. The shop drawings are then reviewed and approved by SEOR and often sometimes also may be reviewed by the local building official if they so choose. (rare, but has happened to me)

We would often laugh that no matter what we showed in terms of using either screwed or welded connections, the contractor would always request the exact opposite of what we showed. We then sometimes would show both welded and screwed connection details.. but wow what a lot of information.

 

[steellion]

Other than some typical notes on the front of the drawings, we provide very little information regarding the light-gage steel if it is not part of the primary structural system. Either the light-gage engineer will follow the details and it will force them into a design that may be sub-optimal, or they will just ignore the details and do it their own way. It sounds like ExcelEngineer's preference is that the building EOR show nothing to allow the light-gage engineer freedom in their design.

 

[msquared48]

If this light gage steel is for an Architectural fascade, I rarely will detail anything relating to that unless asked to do so by the Architect.

If I see a problem with how the Architect visualizes the light gage steel framing, I will submit a detail change that is usually accepted (I never lie).

Mike McCann
MMC Engineering

 

[XR250]

@Steelion

That is fine if they do not show anything. The problem is that if they are not paying attention, they will allow the Arch. to show some crazy detail that is not even possible with light gage. Some EOR's are good about this and provide red iron at the appropriate locations - many are not and the whole process turns into a mess (seems to be the trend).
For instance, just finished a job where the arch was showing vertical deflection joints in the MIDDLE of a 14 ft. span stud, bypass condition stud. Seems he thought the ACM panels needed it. Great, lets put an f'n hinge in the middle of a stud span. The EOR provided no assistance at all (and did not even notice the detail for that matter - nether did I until I was about done with the job.) Their position is , the sub bid it that way so it is your problem.


That is why I feel the LG should be pre-engineered by a light gage engineer prior to the Arch. drawings ever even being released.