Reverse Engineering Fabric Building

[cjowett]

I am looking for someone that could reverse engineer some structural drawings for me.
I bought a fabric shelter from a person off Facebook Market place but it didn't come with engineering diagrams or specs. In order to get a building permit the township is asking for drawings with an engineer's stamp so that they know it meets Ontario building code. Is there an engineer here that could reverse engineer the drawings for me, for a fee obviously and with a lot of support from me getting all the dimensions and details? The original manufacturer seems to have gone out of business so I am unable to get anything from them. Attached is a page from the assembly manual with as much detail as they provide.

TMG Industrial sell a similar building. Theirs uses 2" round 15 gauge tubing and they claim 60 lbs/sq. ft snow load. This one that I have uses 2 5/8" x 1 5/8" oval tubing and is 13 gauge so I am confident it will meet the code. I just need to prove it to the building department.

 

[JStephen]

The ideal solution would be to locate the actual person responsible for designing these in the past.
You could potentially run into a lot of issues, and it may be hard to say until you spend a good chunk of money.
If the original structure was designed for a lower snow load, lower wind load, less-exposed wind loading, designed to an older code or different code or less critical use (say, agriculture), or, simply wasn't designed, it may simply not be possible to certify it for your application.
You gain a fair bit of efficiency in doing repetitive design that is just like the other stuff you've done, so anybody new jumping on that will have more of a challenge working out the details than what the original designers did.
In some types of work, it is not really possible to certify it after the fact, so, for example, if the question comes up of whether welding was done by certified welders, or whether welding processes met the welding codes, etc., those questions may be difficult or impossible to satisfactorily answer. Similarly, if you need mill test reports for the steel or test reports for the fabric. So be absolutely sure of what you will need in order to get the whole thing approved before spending any more money on it.

 

[LittleInch]

Best solution I think is to re list it on FBM with the proviso that it needs to be put up somewhere where they don't need stamped engineered drawings.

That looks very much like a PEMB but with even dodgier shear walls or connections between the frames (Is it only the end two that have any sort of bracing?
PEMBS are pretty notorious for running over the limit, never mind at the limit of structural design.

What is the cost if you needed to buy a certified version from TMG? Then divide that number in two or three and that's the max you can spend on engineering before it becomes more expensive than just buying a new one. If someone is used to designing PEMBs or whatever they call them now adays (Modular buildings?), then you might stand a bit of a chance, but you've probably got to send samples of the frames away to get tested to find out what material properties are.

No material specs or docs, no welding details, no code design data, what you have really is a lump of scrap metal and some fabric. Sorry.

I see the same question posed loads of times when people have a Pressure vessel with no forms, no plate on the vessel just here's one we found out the back, can we use it? Answer - No.

Here is the attachment.

 

[MintJulep]

That's not a building. Why does it need to meet the building code.

It's a tent, at most a temporary structure.


From the TMG website.

These units are all sold as DIY installations. Due to varying regulations required by individual municipalities, TMG Industrial is not able to provide engineered drawings, or any snow and wind load certifications. It is up to the purchaser to determine any local requirements before purchasing

 

[jhnblgr]

These things are notorious for collapsing

 

[phamENG]

for a fee obviously

From a lot of the posts we get here from non-engineers, it seems it's not obvious at all, so thank you for acknowledging that this is our profession and what we do to make a living. I appreciate it, and I'm sure many others here do, too.

As for finding an engineer here to hire, that's unlikely. That engineer will have to be licensed in Ontario, which only a few active members here are. And of them, I doubt any would be willing to take something like this on without going to the site, taking their own measurements, and assessing the condition of the existing structural members. So your best bet is to locate engineers close to you that can come out and do just that.

It's a tent, at most a temporary structure.

I disagree. The scale of this thing suggests it's meant to stay up for quite some time, not be set up and taken down in an afternoon for a party. Fabric structures are employed as permanent structures all over the world. The building 'cladding' may require more frequent repair/replacement than other kinds of construction, but that doesn't make them temporary.

 

[LittleInch]

WhichTMG building?

This one looks similar and stated no engineering drawings available.

30' x 50' Straight Wall Peak Ceiling Storage Shelter with Heavy Duty 11 oz PE Cover & Drive Through Doors, TMG-ST3050E(Previously ST3050)

The TMG-ST3050E Fabric Peak Ceiling Storage Shelter provides an easy to assemble, durable outdoor storage solution or workshop for your farm, - TMG Industrial USA

www.tmgindustrial.com

Don't know where you found the snow load??

 

[SWComposites]

but, but, it has "commercial grade" framing and fabric.

 

[LittleInch]

From a lot of the posts we get here from non-engineers, it seems it's not obvious at all, so thank you for acknowledging that this is our profession and what we do to make a living. I appreciate it, and I'm sure many others here do, too.

As for finding an engineer here to hire, that's unlikely. That engineer will have to be licensed in Ontario, which only a few active members here are. And of them, I doubt any would be willing to take something like this on without going to the site, taking their own measurements, and assessing the condition of the existing structural members. So your best bet is to locate engineers close to you that can come out and do just that.


I disagree. The scale of this thing suggests it's meant to stay up for quite some time, not be set up and taken down in an afternoon for a party. Fabric structures are employed as permanent structures all over the world. The building 'cladding' may require more frequent repair/replacement than other kinds of construction, but that doesn't make them temporary.

Well. It might not be a "tent", but it sure isn't a "building". Kind of in a grey zone, a bit like trailer parks where the homes are classified as temporary and hence avoid a load of requirements you would need for a permanent building.

 

[Ron247]

so I am confident it will meet the code. I just need to prove it to the building department.

Many of us do this for a living, and speaking only for myself, I am not confident it will meet the code, why are you?

Temporary or Permanent does not change much in the world of design loads. It is only temporarily dangerous is not a good selling point.

I have seen several products with notes similar to the one posted by MintJulep from TMG, "These units are all sold as DIY installations. Due to varying regulations required by individual municipalities, TMG Industrial is not able to provide engineered drawings, or any snow and wind load certifications. It is up to the purchaser to determine any local requirements before purchasing".

First, I can supply engineering drawings and calcs for anything I do, that does not mean I am certifying it to meet a specific code and local.

When reviewed, either they did not work, or failed to have the abilities/criteria they claimed to have. One was a log cabin, 2 were "Carolina Carports". I own a Carolina Carport, but the design was supposed to be a 170 mph wind and include a foundation design included per the local salesman. There is a foundation shown and detailed, but it has a note telling me to have a local engineer verify it works for my location and it was for what I guess was "example purposes". The local building officials never noticed the CYA note and previously accepted it. The table of design loads shows the wind speed design to be "Per Table 1". Problem, there are two Table 1s. 1st shows 150 mph, the one below it, (2nd Table 1) shows 170 mph. The Engineer refused to clarify which one was the table for my building. Salesman said it was obvious it was the 2nd table, while I stated a rational person would claim the first table shown is Table 1 and the table below it should have been Table 2. Takeaway, sales people and sale brochures will state/imply more than the engineer is willing to certify. The sales stuff is generally verbal.

 

[phamENG]

a bit like trailer parks where the homes are classified as temporary and hence avoid a load of requirements you would need for a permanent building.

Not in most organized jurisdictions in the States. There are certainly areas where you can get away with most anything, but some minimum foundation and tie down requirements, at a minimum, are usually called for. The frame itself is regulated a little differently, but again, most require that the trailer frame and body be certified by the appropriate governing body. Beyond that, most lending institutions require that the trailers be mounted on a "permanent foundation" which requires an actual foundation designed for the expected loading installed and the trailer mounted to it (and the axles and hitch have to be cut off).

But I guess we're sort of talking past each other with this line of thought - you're from Great Britain, I'm from the US, and the OP is from Canada. So, more than likely, things will be very different for each of us.

In my experience, "temporary" structures are a pain. If you can classify it as temporary, the requirements aren't always clear cut and are often based on the regulations in the area (or whim of the building official). And just because it's temporary doesn't mean it won't require an engineer. In fact, it often requires an engineer to provide justification for lighter foundation and member sizes based on non-standard loading.

 

[SWComposites]

I’m somewhat baffled why the OP would want a building permit for one of these shelters.

 

[phamENG]

I’m somewhat baffled why the OP would want a building permit for one of these shelters.

a socially minded desire to obey the laws and regulations where they live? a selfish desire to avoid the penalties (often monetary fines) that go along with violating those laws and regulations? a little of both?

 

[LittleInch]

Not in most organized jurisdictions in the States. There are certainly areas where you can get away with most anything, but some minimum foundation and tie down requirements, at a minimum, are usually called for. The frame itself is regulated a little differently, but again, most require that the trailer frame and body be certified by the appropriate governing body. Beyond that, most lending institutions require that the trailers be mounted on a "permanent foundation" which requires an actual foundation designed for the expected loading installed and the trailer mounted to it (and the axles and hitch have to be cut off).

But I guess we're sort of talking past each other with this line of thought - you're from Great Britain, I'm from the US, and the OP is from Canada. So, more than likely, things will be very different for each of us.

In my experience, "temporary" structures are a pain. If you can classify it as temporary, the requirements aren't always clear cut and are often based on the regulations in the area (or whim of the building official). And just because it's temporary doesn't mean it won't require an engineer. In fact, it often requires an engineer to provide justification for lighter foundation and member sizes based on non-standard loading.

I agree. I meant it on terms of the actual trailer in terms of things like insulation, structural attention etc, but J think we're on the same page. The fabric is clearly much less strong than a solid material like corrugated steel which can add or be part of the structure. One big rip in the fabric and it all falls down.

 

[canwesteng]

This is what I see being needed to truly sign off on the building:
-A day or two with a tape as builting it
-A certified weld inspector to visually inspect the welds
-A couple coupons taken to determine steel strength
-A few weeks of analysis
-Probably more lateral bracing installed since these often rely on the fabric somehow, which is not something someone unrelated to the manufacturer will be able to sort out

Saying it's impossible and no one would do it isn't true, we do stuff like this on structures without drawings when needed. But the cheapest thing to do is buy a new fabric building.

 

[MintJulep]

Canada has a "farm building code".

National Farm Building Code of Canada 1995 - National Research Council Canada

nrc.canada.ca

Buy a rototiller, park it in the corner.

Bing! It becomes an agricultural equipment storage occupancy with almost zero requirements.

A few potted tomatoes inside and it's a greenhouse with similarly lax requirements.

Or, perhaps the large number of these things available unopened in their original boxes on eBay, Facebook marketplace etc. is a clue.

 

[Tomfh]

Probably not the best structure if you are looking for the "building permit" pathways. I would have thought you'd just build the thing?

 

[ThomasH]

It seems that the OP has left the discussion after the first post. Perhaps he bought this "thing" on Facebook Market and expected a minor cost to make it usable. Unfortunatly the idea didn't work as expected.

 

[cjowett]

Some great feedback here. Thank you to everyone for your thoughts and insights. I'm quite frankly surprised by the number of responses.

I should have clarified that this IS an agriculture use building. It is for hay and equipment storage. I will have a space in one end that horses will be able to get into to get out of weather even though they tend not to do that but they won't be confined in it "just in case". My plan is to ensure the building is protected from them so rips don't occur prematurely.

 

[cjowett]

The ideal solution would be to locate the actual person responsible for designing these in the past.
You could potentially run into a lot of issues, and it may be hard to say until you spend a good chunk of money.
If the original structure was designed for a lower snow load, lower wind load, less-exposed wind loading, designed to an older code or different code or less critical use (say, agriculture), or, simply wasn't designed, it may simply not be possible to certify it for your application.
You gain a fair bit of efficiency in doing repetitive design that is just like the other stuff you've done, so anybody new jumping on that will have more of a challenge working out the details than what the original designers did.
In some types of work, it is not really possible to certify it after the fact, so, for example, if the question comes up of whether welding was done by certified welders, or whether welding processes met the welding codes, etc., those questions may be difficult or impossible to satisfactorily answer. Similarly, if you need mill test reports for the steel or test reports for the fabric. So be absolutely sure of what you will need in order to get the whole thing approved before spending any more money on it.

Some great insights here. I will have to speak with the building department engineers to see what they are expecting. Definitely someone that does this all the time could make much quicker work of generating the diagrams than anyone else.
I would love to locate the original designer but I don't hold much optimism for that. My son suggested using LinkedIn, so I will try that but given the company seems to be gone (and off-shore) I'm not hopeful.