Shop Drawing Review
Shop Drawing Review
(OP)
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.






RE: Shop Drawing Review
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).
RE: Shop Drawing Review
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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RE: Shop Drawing Review
RE: Shop Drawing Review
After all, you may need to add a tolerance dimension to the architectural dimension.
RE: Shop Drawing Review
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.
RE: Shop Drawing Review
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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RE: Shop Drawing Review
RE: Shop Drawing Review
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.
RE: Shop Drawing Review
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.
RE: Shop Drawing Review
RE: Shop Drawing Review
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.
RE: Shop Drawing Review
RE: Shop Drawing Review
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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RE: Shop Drawing Review
RE: Shop Drawing Review
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.
RE: Shop Drawing Review
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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RE: Shop Drawing Review
RE: Shop Drawing Review
RE: Shop Drawing Review
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.
RE: Shop Drawing Review
RE: Shop Drawing Review
I can't imagine sealing a drawing that did not include such a basic thing as plan dimensions. In fact, in my world, that might be considered negligence, since such dimensions determine flexural capacity of beams and load on columns. We always dimension things like how far the edge of slab is from a supporting member, elevations of slabs, and, usually, slab openings. Are these "layout dimensions", or am I missing something?
In fact, I have a presentation I have done across the country discussing the need for engineers to coordinate and provide dimensions, because it is critical to an efficient construction process and to assure the design intent is provided in the CDs.
As far as checking shops goes, the current practice of not actually checking them, and passing the responsibility to others, goes back to the collapse of the walkway at the Hyatt in KC. The series of unfortunate events included a failure by the engineering team to identify two critical but seemingly minor changes, between the engineering drawings and the shops, that were the physical cause of the collapse. The change was made for constructability reasons and the contractor did not realize the change interrupted the load path. A rushed shop drawing check by a junior engineer who was not familiar with the design of that element missed the change. Since that time, the industry has chosen to avoid liability by doing less to avoid a mistake. There are engineering firms that take this very seriously. They detail carefully, check shops thoroughly, and they inspect during construction. Unfortunately, owners seldom want to pay for that level of engineering service.
RE: Shop Drawing Review
Also agreed that checking shops is underrated.
RE: Shop Drawing Review
Your structural stuff will get built first, long before any architectural-only stuff, so it must be right. What structural shows is what gets built. I've also seen in a lot of instances that the GC does not even send the architectural drawings to the steel shop, let alone the written specifications.
RE: Shop Drawing Review
- In Canada: Like Kootk, I have found that Canadian firms frequently do not dimension but instead refer to a specific dated release of the Architectural drawings. I hate this, disagree with this passionately, and refuse to do this in our own practice.
- In New Zealand: The Architectural drawings frequently do not show dimensions and overall layouts. These are found on the Structural drawings. The Arch shows egress lengths, specific little detail dimensions, etc. Nothing affecting spans and overall room dimensions. This has the huge advantage of the person who's work is affected by wall positions, lintel lengths, etc, being in command of these dimensions.
RE: Shop Drawing Review
RE: Shop Drawing Review
RE: Shop Drawing Review
RE: Shop Drawing Review
RE: Shop Drawing Review
RE: Shop Drawing Review
I think that is why the Aussie system developed the way it has. I still have memories, in the US, of late nights spent checking and changing dimensions due to last minute architectural revisions just before the last addendum. And with Australian architects tending more toward sculpture than practicality, I wonder often how the detailers work it all out so well.
RE: Shop Drawing Review
Likely goes like this: Detailers work for the Contractor, who just says it will cost more. More often than not detailers, shop workers, and the contractor's plethora of staff in general have more power to say "No" to a change than we do...
RE: Shop Drawing Review
RE: Shop Drawing Review
RE: Shop Drawing Review
RE: Shop Drawing Review
I think it is lazy if you cannot provide dimensions and some CYA statements saying which architectural drawings it is based off of and that the contractor and architect are responsible for confirming the dimensional accuracy.
When I go to peer review another engineer's work I don't want to be flipping back and forth between drawing sets either. I should be able to redesign the building from the structural drawings alone and should not have to go hunting for a dimension I need for design. If during the course of your design of the building you needed to hunt for a dimension then you should be including that dimension on your drawing. Passing the buck onto the contractor to successfully figure out is a cop out and is just asking for mistakes.
From my own experience more mistakes happen when the contractor is expected to hunt down a dimension.
RE: Shop Drawing Review
RE: Shop Drawing Review
RE: Shop Drawing Review
Layout dimensions are the bane of my existence. If you are building a rectangular ground up big box store with column lines exactly 30ft O.C. both north and south I assume its easy, but if you are doing a retail renovation in an 1920's NYC building, noone, not even the architect has complete control of the layout. You are working from a hodge podge of site measurements and smudged low-res scan of original drawings, plus you have an owner and architect who are designing as they build.
RE: Shop Drawing Review
RE: Shop Drawing Review
I rarely check dimensions on shop drawings. I am checking for general conformance not every detail. If the sizes and locations match the drawings then I leave the dimensions alone unless specifically requested to review them.
RE: Shop Drawing Review
I think my own goal on shop drawing review is to verify communication - not necessarily accuracy. I think spot checking difficult areas, unique areas, etc. - both with dimensions and connections is key.
This is sort of like the analogy of site-visits and the observations vs. inspections issue.
With inspections - you are looking at most everything back-checking the contractor's actual work.
With observations you are spot checking unique areas and perhaps some standard areas to determine whether, in general, the contractor is (and is capable of) understanding your documents.
Two completely different goals and I view shop drawing review as more like verifying communication rather than comprehensive accuracy.
Over the years I've tended toward showing more dimensions on my plans but still adding the caveat that cross-checking between all disciplines is still the job of the contractor.
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RE: Shop Drawing Review