Shop Drawing Review

[SteelPE]

When doing shop drawing review, specifically steel shop drawings, do you guys check dimensions or leave that for the architect to verify? Or do you even expect the architect to look at the drawings? I have had some architect say that checking the structural shop drawings is my responsibility. When it comes to dimensions of I am finding that I may note the architect to verify dimensions (say around a stair or a slab opening) only to have the shop drawings come back a month later with the same questions in regards to dimensions I asked the architect to verify.

 

[manstrom]

For liability reasons, I may add a note for the contractor and architect to verify dimensions. In reality, I know that this won't happen. My butt is covered, but that doesn't keep me out of trouble.

Whoever said that architects are basically cake decorators is correct. The level of competence and effort that I have seen from architects over the last decade has dropped significantly.

You should provide clear dimensions to all beams and grids. If these are correct, then the shops should be easy. If my drawings are good, I'll spot check a few dimensions on the shops.

If there are specific areas that should be indicated by the architect - a slab opening or elevator size, I would direct that specific area to the architect (assuming they don't have it dimensioned).

 

[JAE]

Read through AISC's Code of Standard practice - specifically sections 3.3. and Section 4.

From those sections the Designers (Owner's Designated Representative for Design) are responsible for providing to the contractor a set of documents that have sufficient information to build from. (section 3.3 and its commentary).

So if the contractor (i.e. the fabricator that creates the steel shop drawings) has a problem determining a dimension, or there is a discrepancy on the A/E plans, then it is up to the A/E "team" to help determine the answer.

I would see it as both the architect and structural engineer need to work together to determine the correct value.
Who specifically does this can be vague at times (thus your post) but sometimes the dimension can be based on architectural needs (i.e. a corridor minimum width) or structural needs (alignment of collectors, braces, etc.) and that can determine perhaps who figures it out.

However, AISC does suggest that the dimensional fit-up of the parts is solely the fabricator's responsibility.



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[FootNMouth]

I typically note for "ARCH TO VERIFY" on dimensions that are not specifically called out in arch drawings. I check slab edges and openings in the shop drawings compared to arch and structural, this is a good opportunity to ensure that all the slab edges are coordinated. If the fabricator asks for a dimension that is provided in the arch drawings,I note which sheet it is shown on. This helps when there is later a discrepancy because I can point to the exact sheet where I pulled the information from.

 

[jike]

Why not call the Architect or his project coordinator and work with him to provide the dimension? Tell him that you need more info to determine the required dimension for the contractor.

After all, you may need to add a tolerance dimension to the architectural dimension.

 

[Brad805]

We do, but our stamps still note that the contractor is ultimately responsible. The problem that has arisen over the years, is nobody seems to want to check them and when things go wrong we end up in the middle of a discussion about how or whom should fix something. Years ago i would see the site superintendent siting in his job shack checking dimensions and reviewing drawings, but now that same guy is running several jobs and does not seem to have time.

The arch review of structural steel shops borders on being pointless in my view. This type of job gets assigned to whatever tech they have on staff and his/her experience does not always add a lot to the process.

 

[JAE]

I think that any dimension that CAN be figured out from the drawings is the responsibility of the contractor.
Overall dimensional fit-up (how the pieces fit together and have consistency in their dimension) also is the responsibility of the contractor.

But any dimension that cannot be figured out from the drawings is the design team's responsibility and should be coordinated.
As a structural engineer, there may be dimensions that I don't care about but others that are critical to our design.

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[SteelPE]

JAE, funny about the AISC COSP. I have seen many drawings from large well known engineering companies that show no dimensions on their drawings. Not one single dimension. They leave that up to the architect.

 

[JLNJ]

Since we are an A/E firm, most dimensioning ends up in the E's lap, primarily because the architects are not particularly good at figuring out the sorts of details which the steel guy is intestested in. Especially in and around stairs. Slab edges and edge support always seem to need attention.

On shop drawings, I'm primarily looking for the proper understanding of concepts, not necessarily dimensional content. Where I know there are gaps in the drawing info, I'll make sure the steel guy's interpretation is correct. The best scenario is to have the detailer submit an RFI to the architect. Right now I'm dealing with a job where the detailer has just guessed rather than asked. Now I have a set of detail drawings I'm reviewing where I need to do the coordination and ask for some painful re-detailing. Detailers get crapped on so often I hate to make them make changes.

You also have to know your audience. A really good set of contractors will coordinate bewteen trades and sort things out among themselves. The bigger the job, the more likely you are to get this sort of contractor coordination. Smaller jobs, with lowest-cost local guys, tend to have fewer people to sift through the design drawings for opening sizes and locations, edge of slab dimensions, etc.

In the end, someone has to to it, and good luck getting the architect to sharpen his pencil and give direction to a steel fabricator.

 

[KootK]

When I used to work in the US, we'd basically dimension our drawings anticipating what the steel fabricator would care about. Plan locations, axis rotations, top of elevations... you know the drill. We considered our drawings to be uncoordinated util we sorted those things out. Obviously, they all matter somewhat structurally. When shop drawings came in, they would be almost fun to check.

When I returned to Canada, I discovered that we do things differently. For fear of liability, we leave everything up to the architect which often means that things don't get dimensioned at all. I'm now the EOR that annoys folks like SteelPE. From what I've seen of this system, the consequence are these:

1) We still ultimately have to figure everything out. We just do it during construction when it's 1000% more annoying.

2) Sometimes, when we figure out the final dimensions, we discover that we're not so happy with them from an engineering standpoint. Unfortunately, because we don't coordinate our drawings properly, we don't have much leverage to ask for changes.

3) This is merely a suspicion that I harbour but I suspect that error / delay claims resulting from non-existent coordination result in much more liability exposure than imperfect coordination ever did.

The greatest trick that bond stress ever pulled was convincing the world it didn't exist.

 

[Ron]

Interesting discussion....In general I agree with JAE. I have an architect that I've worked with who considers that all dimensions are under the architect's purview. Certainly in the event of a discrepancy, the architects dimensions should prevail as he/she has overall responsibility for things fitting together. ALL dimensions are a subset of the architectural design.

 

[TLHS]

How the heck do you design things without dimensions on the drawings?

I don't do work with architects, but I don't know how I'd stamp something lacking critical dimensions. I would think it would mean putting my design's safety in the hands of drawings I don't have control over.

 

[glass99]

Structural engineers always exclude layout dimensions from their scope. Its kind of basic!

 

[JAE]

With the advent of BIM the arch/struct relationship is changing in relation to the x, y, z geometry of the building or structure.

The models (architectural and structural) are essentially built off one another and are periodically updated on each other's computer. Thus the model itself
contains all the geometry needed. The 2D drawings that result still might have missing or mis-labeled dimensions but the physical "shape" is there and true.

More and more contractors are requesting the models to assist in their steel (and concrete, etc.) fabrication drawings. So this whole discussion we've been having here may be slowly becoming moot.



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[glass99]

JAE: Good point about BIM, but the discussion then changes to "who's fault is it that the layout geometry is wrong".

 

[SteelPE]

I don't agree with JAE in regards to the BIM making the issue moot. Wasn't email suppose to eliminate paper? I have so much paper around here it's probably a fire hazard.

Recently I worked with a high profile architect on a project who refused to send anyone CAD information w/o signing a consent form stating that the CAD files are for reference only and the architect has no responsibility if the information contained withing the files is even correct. There was a discussion about it here:

http://www.eng-tips.com/viewthread.cfm?qid=362937

I refused to sign the document and I never received the CAD files. So I'm sure as BIM expands there will be more and more of these agreements going out. Especially after the first lawsuit where the architect gives the drawings to the GC and the GC in turn sues the design team because something was incorrect in the model.

 

[JAE]

Well I did say "slowly" becoming moot.

The discussion was on the issue of the contractor determining dimensions from 2D plans where dimensions are not shown, or are shown in a random way (some on arch and some or none on struct plans)

With BIM you still will have 2D drawings (at least for the time being) with some or incomplete dimensions shown.

The contractor then asks for and sometimes gets a BIM model and the dimensional framework is there for them.

SteelPE is on target with the concern of lawsuits over models and such. That I think is the biggest challenge to the use of BIM - working out how the information is passed from designer to builder.



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[Archie264]

Pretty eyewash can make one miss deficiencies. Often BIM models contain conflicts that would not have occurred with well-thought-out 2D drawings. (Please note the caveat, “well-thought-out”.) Just my experience.

 

[dcarr82775]

Back to the original topic (although I find the whole conversation interesting), I was talking with a lawyer client on a case and said the engineer specifically notes his submittal review does not include things like dimensions. His response was that he knew that, and he had also never had that argument work in court. So we are on the hook one way or the other. I think you did your due diligence noting "Arch Verify" so long as you also told him it was coming and he needed to provide the information. I find you have to tell them that since they don't really look at them. I would pass the submittal along to the architect again.

 

[manstrom]

Structural drawings without dimensions are not complete in my opinion. The correct answer is for structural drawings to have dimensions that are double checked against the architect. In my experience, this is frequently not done.

I have seen structural foundation plans or steel plans without any dimensions at all. At first I'm jealous that they didn't have to do all the dimensions, then I wonder how they will build it.

Everyone is trying to cover their butts, no one wants to take the reins.