American Buildings Company ca. 1995 2

[phamENG]

Anyone familiar with the standard material used by ABC in the mid 90s for Metal Building System main frames? Looking at some options for adding insulated panels inside, and we need to hang them from the overhead. When I assume A36, I get results I expect - the existing construction is coming in at 1.00 and 1.01 utilization ratios at critical points based on DG 25 using current code. I know they're using Gr. 55 plate nowadays for built up, tapered members, and I know the usage goes back a ways, but I'm not sure how prevalent the usage was into the 90s. Was it a standard or an "as needed" upgrade?

I have a call in to ABC to see if I can talk to somebody about it (maybe even pull the original drawings if somebody forgot to clean out a drawer), but figured I'd ask. I know a handful of the members here are active in the MBS industry.

Thanks.

 

[driftLimiter]

I don't know from that long ago but I know now that they use combinations of material for plate girders that include Gr 55 Flanges. Its going to be tough I bet for someone to say what standard they used without the original drawings I would think. What I was told by the ABC guys is that weight of steel is king and if they can use Gr55 plate to reduce member sizes they will do it almost always (nowadays).

 

[SandwichEngine]

I'm in the PEMB industry. I've never seen anyone use anything except 50 ksi and 55 ksi but my experience doesn't go back that far and I've never worked for ABC. One thing I'll note is that they got bought by Nucor Building Systems a while back and eventually transitioned from their own proprietary software to Nucor's proprietary software. I say that to say that even if they could find the computer files, they wouldn't be able to check them anymore.

I'm also very surprised to see a conventional structural engineer doing an analysis on a PEMB structure. PEMB companies won't even touch each other's stuff due to differences in engineering philosophy, types of standard details, etc. I'm not saying it's a bad idea. This is just the first time I've heard of someone taking on the challenge. Are you hand calcing it all or are you doing that in tandem with Risa or some other FEM software?

 

[Settingsun]

even if they could find the computer files, they wouldn't be able to check them anymore.

I'm also very surprised to see a conventional structural engineer doing an analysis on a PEMB structure.

PEMB companies won't even touch each other's stuff

#1 & #3 must mean that #2 is fairly common.

 

[j19]

For built-up straight and tapered members, I can confirm that in the mid-90's American Buildings Co used 55 ksi yield flanges up through about 12" x 1". Larger than that was usually 50 ksi. I don't remember exactly where the split in web yield strengths was at but I think that all webs less than 1/2" were 55 ksi. Webs 1/2" and thicker would have been 50 ksi.

 

[phamENG]

SE, Initial checks in RISA (they incorporated the AISC/MBMA design guide), but I'll be doing hand calc verifications and I'll do connection analysis by hand.

I don't like doing them, but it's what needs to be done. Steel is steel. Just because they have a different design philosophy doesn't mean it can't be analyzed - just means I have to give my client bad news more often on these. (Fortunately my client in this case has a visit in the industry and understands.)

j19 - thank you. I'll still need an official confirmation, either from ABC or coupon testing, but it's good to have confidence that we'll get what we need.

 

[JedClampett]

Pham, The problem is that as soon as you touch these contraptions:
[ul]
[li]You own them.[/li]
[li]And the bad news you give them is that, the building doesn't work and probably never worked.[/li]
[/ul]

As a structural engineer, I was taught that you're responsible for your designs. In perpetuity. And when you shuffle off your mortal coils, whoever is working for your company is responsible. I'm not talking about doing free work, but paid for work. It just pisses me off when the original PEMB design firm, who's still around, won't touch their own designs.

 

[phamENG]

You own them.

Yep. That's why I don't like doing them!

And the bad news you give them is that, the building doesn't work and probably never worked.

In most cases, yes. In this case - it was a warehouse, and it worked fine for that. It's when you start adding to them that it stops working.

But yeah, I've had people ask me to do conversion to office buildings, and that never flies. Best one was one recently that hadn't been built, but the owner's volunteer "PM" (worked in an unrelated construction field) approved the purchase of the Metal Building System and it was already in production. They just wanted me to design the foundation. Oh, and then after it was up they'd fill it in with 2 stories of light gauge framing, layout TBD. All in a metal building designed to be a warehouse with H/60, no insulation, and no consideration for anything other than the sale. I told them I'd only take it if they cancelled their order so I could write a proper spec, and gave them my fee. They said "but we only need a foundation." And so I told them good luck finding one.

There are a lot of good PEMB companies out there, and I understand that the companies are selling a product and can't be expected to decipher everything the client could ever want...but when somebody comes to you to build a church and you sell them a building that is, by all accepted steel construction standards, barely passable as a large garage...something's wrong.