Is It Common For American Steel Fabricators Not To draw To Scale
Is It Common For American Steel Fabricators Not To draw To Scale
(OP)
I am currently checking structural steel fabrication drawings prepared by a leading American Steel Fabricator (World leading even) and the drawing are not to scale. I am in the UK and the project is in Africa.
I requested drawings to scale and was told that the fabricator does not produce drawings to scale and that I should use the dimensions shown on the drawing.
This seems a bit out of date to me. The current thread in the industry is to produce drawings that integrate all the design team memebers and fabricators. Working 3-D models that show the structure, architecural details and services is what we are all aiming for.
Considering this is it normal for American fabricators to produce drawing that are so user unfriendly that they don't even meet the basis requirement of being to scale.
I get the feeling that these drawing are produced by a computer program based on inputing data into a standard set of questions.
The buildings are of portal frame construction.
I requested drawings to scale and was told that the fabricator does not produce drawings to scale and that I should use the dimensions shown on the drawing.
This seems a bit out of date to me. The current thread in the industry is to produce drawings that integrate all the design team memebers and fabricators. Working 3-D models that show the structure, architecural details and services is what we are all aiming for.
Considering this is it normal for American fabricators to produce drawing that are so user unfriendly that they don't even meet the basis requirement of being to scale.
I get the feeling that these drawing are produced by a computer program based on inputing data into a standard set of questions.
The buildings are of portal frame construction.






RE: Is It Common For American Steel Fabricators Not To draw To Scale
RE: Is It Common For American Steel Fabricators Not To draw To Scale
In Europe steel fabrication drawings are generally drawn to scale. We also get job specific 3-D fabrication drawings.
European fabricators do produce a lot of drawings as they produce general arrangements and also a drawing for every individual member. In America it seems to be a general arrangement drawing that is not to scale and then generic details that are used for every job and not specidfic to any one projects. Its just a diferent way of doing it but I still maintain that a basic requirement is that engineering drawings should be to scale, or at least general arrangements should be.
Having scale drawings allows drawings to be overlaid for easy checking of main dimensions.
I find the American fabrication drawing we received very slow to check.
I do a lot of jobs using precast concrete building systems and again we get drawings to scale and job specific 3-D drawings from the fabricator.
RE: Is It Common For American Steel Fabricators Not To draw To Scale
I don't know about GAs not being to scale, generally they are initially prepared to scale but subsequent revisions may be made Not To Scale with changes to some of the dimensions to save the time and manhours.
Our shops would not know what to do with your drawings, the whole system is built around the present method. Our designers are used to the system too.
I checked detail drawings back in the UK, in the fifties and sixties, and they were done the same as we do them now.
It would be interesting to see a comparison of detailing costs per ton/tonne.
Michael.
Timing has a lot to do with the outcome of a rain dance.
RE: Is It Common For American Steel Fabricators Not To draw To Scale
The link below is to a website that sells software to steel fabriactors. There is an image in the centre of the websites screen and if you hover your mouse over the boxes either side of it you will ssee sample images of the type of drawings we receive here. X-Steel is another package that does the same.
http://www.acecadsoftware.com/steel_detailing
The guys that use these packages are cad technicians and not engineers.
This type of software is linked to the cutting and drilling machines in the shop which automatically do that work with no measuring etc being required.
In term of what happened in the 50's and 60's in the UK my experience of looking at old drawings is that GA's were drawn to scale and details were also job specific and drawn to scale.
It seems that things are more systemised in the States. The US systems seems less flexible to me and it certainly doesn't save me time in the design office checking the fabricators drawings.
Here's a link to Tekla which are based in the US that also shows the type of drawings we get in Europe.
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Can anyone tell me how long it would take one person working to the American system to produce the full drawings for a 40 yard x 100 yard standard portal frame building without mezzanine floors or fancy details?
RE: Is It Common For American Steel Fabricators Not To draw To Scale
If I were detailing a beam or column that only had end connections and holes, and it didn't fit on my standard 1"=1'-0" sheet, then I would simply stretch the beam or column in the long direction until it fit the sheet.
To my knowledge this is a very typical practice in the U.S. and I think it is a very good one.
RE: Is It Common For American Steel Fabricators Not To draw To Scale
http://www.FerrellEngineering.com
RE: Is It Common For American Steel Fabricators Not To draw To Scale
RE: Is It Common For American Steel Fabricators Not To draw To Scale
just like toad jones said.
imagine a very long column with holes due to connecting members. if you draw it to scale you wont see the holes distances. they usually stretch beam or columns. details are usually drawn to scale though.
RE: Is It Common For American Steel Fabricators Not To draw To Scale
If I detail out a truss or large frames, then I'll choose a drawing scale that will fit the whoel assembly and start from there.
These are just my reasons.
RE: Is It Common For American Steel Fabricators Not To draw To Scale
I like it that way, but its whatever you are used to I suppose.
But what connecteng said makes a lot of sense and I think his family has been doing this a long time....
RE: Is It Common For American Steel Fabricators Not To draw To Scale
RE: Is It Common For American Steel Fabricators Not To draw To Scale
if there is a particular messy connection "detail" i will draw that to scale.
I do not do all my "detailing" of beams and columns to scale unless they fit the sheet by virtue of being relatively short.
Like others have said, I DO NOT want shop and field guess scaling drawings EVER. I prefer they called me. All my drawings say on them "DO NOT SCALE", even though a scale may be provided on the drawing.
RE: Is It Common For American Steel Fabricators Not To draw To Scale
In the UK we use cad drawings as virtual 3-d buildings and once the model is built it is possible to take snap shots of the sructure wherever you want and from whatever angle.
The big benefit in having accurate to scale fabrication drawings is they can be overlaid on the consulting engineers or architects drawings and any diiference are very easy to identify.
Cad drawing files have more uses than just pieces of paper to be read in the workshop or on site.
We are working towards intergrating architectural, structural and mech/elec information in one drawing file. Doing this makes it very easy to identify clashes between the structure and services etc.
The new Terminal 5 at Heathrow Airport in London, England was completely 3-D modelled including all services and architectural details with the results that huge sums of money were saved because services did not have to be redone due to clashes. On big jobs it makes sense financially to invest in decent drawings.
I have just finished checking 12 steel frame buildings using only the fabricators dimensions as the drawings were not to scale. Even the the general arrangements were not to scale. For me it was a real pain in the butt.
RE: Is It Common For American Steel Fabricators Not To draw To Scale
Let me make one thing clear...I draw everything to scale when I detail on a "master" or "work drawing". I then copy the detail to the shop drawing and only then do I stretch the detail.
I always keep a scale version of the item. I don't just randomly draw the line on the shop drawing right out of the gate.
I'm sure I am describing the practices of many when I describe this.
By the way, some of the BIM jobs I have worked on were complete disasters as far as structural steel goes.
The shop drawings that were "scrubbed out" of the software were pure Busch League.
RE: Is It Common For American Steel Fabricators Not To draw To Scale
RE: Is It Common For American Steel Fabricators Not To draw To Scale
As a heavy process equipment manufacturer I have also been requested by groups outside the U.S. to provide additional drawings and models of equipment suitable for use in BIM models. This includes structural details as well as mechanical equipment. Much of this is just not available in easily distributable formats due to large amounts of legacy data and drawings that are not to scale. As stated above, structures and equipment are all drawn to scale, however, details are generic.
I often get multiple inquiries along these lines as to why things are not to scale and don't you have this or that created...
I believe we are seeing a shift outside the U.S. that is enabled by lower costs of engineering and drafting personnel.
In particular where computer time is cheaper than in the U.S. they have been much more enabled to jump into full 3-D models and also have the drafting time to produce copious amounts of drawings that we in the U.S. see as frivolous.
I am not sure what is right or wrong, but clearly I see a trend that is developing that the U.S. cannot keep up with. U.S. engineers are wearing too many hats to have to be able to produce all the "nice things" that people may now start to intepret as requirements. As an design engineer I am now responsible for all calculations, 3-D modeling, FEA, and full 2-D drafting for shop drawings. Drafters have mostly been cut out of our budgets and workforce in general has been reduced. I am not saying I agree with this, just a statement of current situation.
The other main difference in foreign fabricators using 3-D models is many now produce one detail per sheet. I am not sure if this is driven more by the mechanics of some 3-D modeling packages - such that each part has its own file therefore has its own drawing. This methodology figures highly into production and organization in factory settings.
Easier to distribute 50 peices of paper each with a single detail/part to a less skilled workforce and instruct them to perform the operations in sequence rather than one full size sheet with 50 details that you need a skilled fabricator to understand. I believe cultural differences/management philosphies are really at the heart of this.
RE: Is It Common For American Steel Fabricators Not To draw To Scale
Michael.
Timing has a lot to do with the outcome of a rain dance.
RE: Is It Common For American Steel Fabricators Not To draw To Scale
I typically see the erection drawings (plans, elevations, some sections) to scale. The piece drawings are never to scale for reasons many have explained already. It simply makes no sense to do the piece drawings to scale.
RE: Is It Common For American Steel Fabricators Not To draw To Scale
Not every building project in the UK uses BIM, far from it, but practically every structural steel fabrication drawing is done on Strucad or X-Frame which are 3-D structural steel drawing packages. There is no problem printing drawings to scale. As a consulting engineer I get sent:
*General arrangement drawings in digital format that I can bring into Autocad.
* Shop drawings of every steel member in the project that the package automatically generates. Connection details and figured dimensions are shown on these.
* 3-D persective drawing from whatever angles I ask the fabricator to send.
* More and more steel fabricators are offering Tekla drawing files which allow you to walk through the building with a camera and view the structure from all angles in 3-D. This is useful for tricky complicated steelwork.
The above is industry standard over here. We got drawings from an American steel fabricator that is a world leader and they couldn't even send us general arrangement drawings that were to scale. We thought we had gone back to the stone age.
Bottom line for me is that General Arrangement drawings should be to scale and should by available in didgital format for checking.
RE: Is It Common For American Steel Fabricators Not To draw To Scale
I don't agree that outsourcing has anything to do with the lack of scales on a drawing. The 3D software used by SS fabricators just simply removes useless lines in an attempt to conserve space. Even when the software cuts out useless areas of an assembly, it still knows the correct dimension between parts on that assembly.
Toad, I think you had confused techs running the BIM software. Anyone that suggests it is less accurate than conventional 2D software is not using it correctly. We have been using Tekla for our engineering projects since 2007 and I have done a lot of modelling. The quantity of fit errors has reduced dramatically since starting with BIM. I assure you, Tekla will never ever move a gridline, accidentally offset a detail line, move a column between floor levels, forget to change the location of beam on a detail after the arch made some changes, mislabel a part, or not do a ton of other things that draftsman can do on a bad day. Sure we are all supposed to catch these errors during our reviews, but I am sure we have all missed one before.
Brad
RE: Is It Common For American Steel Fabricators Not To draw To Scale
Brad805
The reason we like scaled digital drawings is that it allows us to overlay fabrication and consulting engineering drawing in Autocad. This dramatically speeds up the time it takes us to check general arrangement drawings, elevations and section. If there is elevations with a lot of openings for window/doors etc at random spacings it can take a while to check using dimensions on the drawing.
Overlaying the fabricators drawing over the consulting engineers drawing tells you within a blink of an eye if any openings are out of place.
The section drawings showing the portal frames we received didn't show the steel column or rafter beam sizes nor did the general arrangement drawings. I had to dig through the reems of numbers in the calculation printouts to find the sizes.
The calculations we received from the American fabricator were also user unfriendly and amounted to reems of numbers without diagrams on a computer printout over many pages. I was eventually able to pick out the main information but it wasn't easy to find.
The American fabricator information system probably works if people are familiar with it but I can definitely say there are better ways to present information.
RE: Is It Common For American Steel Fabricators Not To draw To Scale
I am sure we have all seen the output sheets from Butler, Varco Pruden and the other major pre-engineered steel building manufacturers. They are all using a base 3D modelling program that they customize using the Advanced Programming Interface (API). If you have a C++ programmer you can create automatic input parameters that can pretty much do it all for a specific building style.
Now, if you are the EOR and this is a custom building for a client, then it takes a little longer. There are two basic steps. The modeling and then the drawings. The skeleton is extremely quick to model, but as always the details take the time. To expedite the detailing aspect, Tekla has what are called custom components (CC) (see picture). There are a lot in the package and you can create your own parametric components that are as complicated or as simple as you like. These CC help to speed up the detailing process immensely, since you can save any of your standard company details for use on all of your projects. The drawing production again depends upon your own company standards. If you only want the basic info for a shop, then you can automate this step extensively; however, if you have company standards that you must comply with to create typical engineering style drawings, then it takes a little longer since you must create much of the drawings manually.
Sorry it is not a simple answer, but maybe I helped.
Next time you are given a package of shop drawings you should inquire what software was used to create it. I know Tekla, StruCad and Bentely all have review tools that you can use to review the shop drawings. It takes virtually minutes for any detailer to prepare a model that can save you hours and hours of review time. I know of one recent project that had 20,000 part drawings, and the EOR reviewed all of the documents electronically and returned their markups electronically.
Brad
RE: Is It Common For American Steel Fabricators Not To draw To Scale
Michael.
Timing has a lot to do with the outcome of a rain dance.
RE: Is It Common For American Steel Fabricators Not To draw To Scale
The PEB options are very cost effective, but they sure do eliminate a lot of the customization and they cannot provide much more information other than the basics. We have one L shaped building that has two rows of columns at two interior column lines because they had to split the building into two separate buildings. They would not combine the columns into single larger columns where the two buildings intersected since their system was not setup to do so. Not very good engineering, but they sure did offer a better price than any custom steel building could.
Brad
RE: Is It Common For American Steel Fabricators Not To draw To Scale
RE: Is It Common For American Steel Fabricators Not To draw To Scale
The drawing we received were from one of the two fabricators you have mentioned in your post and it is fairly clear to see that they are using a very automated system for producing drawings. Like you say they have written software to suit there system or altered a standard package. The drawings themeselves contain few errors, and in that sense are good, but from a readability point of view they are the worst fabrication drawings I have seen in 15 years as a consultant. Not user friendly, not to scale and don't show the structural section sizes.
The detail you show from Tekla in the snap is more like what we would see on StruCad drawings from fabricators over here. A lot of the fabricators here are now using Tekla and it is becoming industry standard taking over from StruCad.
Using StruCad I reckon a fabricators draughtsman could draw up a 40 yard by 100 yard basic portal frame building with no mezz floors and straight forward cladding in maybe 2-3 days. I would say the big America fabricators with their own drawing systems are doing drawings a lot more quickly and you can tell from the results.
From an engineering point of view another thing new to me is the lightness of the steel frames. The steel flanges and webs are very thin, between 0.12 and 0.32 inches. The columns and rafters are also tapered. Steel sections this thin don't look like they would take much abuse from something like a forklift hitting them.
Are there standard methods in the States for protecting these really light sections in warehouse type building?
We generally use sections that are less deep but with thicker flanges and webs. We very rarely use tapered sections which I assume have to be made up for every specific project.
RE: Is It Common For American Steel Fabricators Not To draw To Scale
My issue is more with the user-friendliness of the information. I don't know how consultants check fabrication shop drawings in the US but if it takes them anything like as long as it took me the financial savings in producing the drawings are lost in the checking. I'm sure the fabricator doesn't mind how long it takes the consulting engineer to check the drawings.
Is it a requirement in America for the consulting engineer to check the fabrication drawings?
By the way I'm not giving out about America it's a great place. I've spent many holidays and a college summer there. The fab drawings I received I am giving out about!
RE: Is It Common For American Steel Fabricators Not To draw To Scale
RE: Is It Common For American Steel Fabricators Not To draw To Scale
Mike Halloran
Pembroke Pines, FL, USA
RE: Is It Common For American Steel Fabricators Not To draw To Scale
Do you mean 'bollocks'?
RE: Is It Common For American Steel Fabricators Not To draw To Scale
In North America these tapered frames are mostly seen in this building style. You will also see plate girders along these lines in bridges; however, you will never see a bridge with such thin components nor would most ever attempt to stretch the limits as far. Without a highly automated line that can produce 1,000's and 1,000's of tons of steel regularily, it just is not cost effective to produce these frames.
Funny you mention the forklift. A forklift operator managed to punch his entire fork through the web of one frame at an OSB plant we do some work for occasionally and on two other separate occasions, operators at that same plant split a main column (axial loaded) in two at a splice. One of them confessed they have games to see who can load the rail cars the quickest. I suspect these were usually played during the night shift. To protect the columns we have encased the lower region of the columns in a concrete or installed steel bollards around the columns.
I have tried modelling PEB's before from the shop drawings provided and at best I would say I get close. The section depths are never defined well enough to get precise. I have also asked VP to provide their model before, but eventually grew tired of the run around.
I am not a huge fan of this building style. Most of the time the main cost savings are sacrifices in the building envelope. Its not too hard to figure out that tin and rolled batt insulation is less expensive than a more durable wall facade with longer lasting roof assembly. We use PEB's for industrial shops, but always try to persuade our clients to consider other alternates at the same time.
Brad
RE: Is It Common For American Steel Fabricators Not To draw To Scale
What does PEMB stand for?
We are only designing foundations for the building with the steel fabricator designing and fabricating the frames. We have been asked to review the fabricators design. we had to check building dimesions and we did calculations to check the sizes the fabricsator had specified.
It was all also necessary for us to check the frames because the steel was so light and they used tapered column. We are not familiar with this system build so we had to check the steel to get a handle on structural capacities of such lightweight steel sections.
As I said the steel is very light and doesn't lool very robust but it spans the distances and works for deflection, lateral torsional buckling etc. One of the rafters on a portal is 32 inches deep but the span of the portal is only about 30 yards. I am a little concerned about secondary effects and possible distortion of the beam with the flanges and webs being so thin.
Can anyone shed any light on these tapered very thin flanged steel portal frames?
RE: Is It Common For American Steel Fabricators Not To draw To Scale
I have modelled a few of the frames using the Robot structural analysis and design package. Robot allows customised columns and beams to be input where taper sections and different flange/web thicknesses can be specified. My results for bending, deflections, buckling are about 10-15% greater than the fabricators but the section capacities still work to the forces I have found. They are using reduction factors that I don't understand but I'm happy that what they have designed works on paper.
In terms of the design being specialised I would guess that it is very standardised and basically involves putting dimesions and loadings into a pro forma. The output is terrible, just ream of numbers that looks like computer code, no diagrams. It's hard to say if anyone ever looks at it. This fool did and it was ppainful.
RE: Is It Common For American Steel Fabricators Not To draw To Scale
PEMB = Pre-engineered Metal Building
You might want to log on to whatever state the professional is registered and see how long he has been practicing. It sounds like you have a pretty good building size, so odds are you might have one of the experienced guys on your project. You might be able to gain a great deal of comfort by simply calling him and discussing the design with him. Any of us in NA understand those of you on the other side of the pond do things a little different and probably would not mind chatting to you about this.
Good luck with the project.
RE: Is It Common For American Steel Fabricators Not To draw To Scale
I think the lack of robustness of the columns to being hit could be the biggest problem. The buildings are for industrial use and that means vehicles will be driving around.
Thanks for all your helps. The post you put up at 17.45 was very informative.
Cheers
Finn
RE: Is It Common For American Steel Fabricators Not To draw To Scale
I've had a number of architects ask me why my structural details are not to scale. The answer is that I want the reader to be able to see the DETAILS of the details. I could care less if the beam depth is accurately portrayed. I do want to make it easy for inspectors and other to see the number of bolts.
You might actually find as well that having to look at the dimensions and get yourself a bit more involve in the shop drawings from a thinking perspective versus just visual comparison might yield more catches. For example with bar joist they might look right on the drawing but the design might have them short, etc...
It may indeed be a different process over here. But what makes your job easier might make someone else's harder. I think HOKIE mentioned earlier that these drawings are primarily used buy the guys in the shop fabricating the steel. They could care less about whether or not the layout is correct or not. They need to know where to cut. All that said usually the plan view of the steel is to scale from what I've been receiving lately. In fact a lot of time I have to tell them to pound sand when they want my Cad details. There is something to be said for reproducing the drawings. The process often flushes out errors that the engineer of record hasn't thought out or visa versa.
I'm not knocking BIM either cause there are obvious advantages to that as well.
John Southard, M.S., P.E.
http://www.pdhlibrary.com
RE: Is It Common For American Steel Fabricators Not To draw To Scale
RE: Is It Common For American Steel Fabricators Not To draw To Scale
Something I would emphasis is that the 3-D models produced by a drawing package like StruCad are not BIM. They are used primarily to program the cutting and drilling machines with very little cutting being done by man. The drawings produced are also of a very high quality and are easy to check.
As Brad has said it seems I received PEMB drawings that are produced automatically by a computer with little input from an engineer or cad technician. It seems clear to me that these drawings fall a long way short of what is typically produced in the States by a cad tachnician for a steel building.
RE: Is It Common For American Steel Fabricators Not To draw To Scale