PEMB buildings from China? Engineering? 3

Evaluating a design using a planset in a different language isn't that hard... I've managed it in a handful of languages I don't know. Plus as Dik mentions, a lot of foreign engineering happens using loan words from other languages, often english.

Checking calcs in another language is another story, but I'd be building my own calcs (with reference to theirs), so neither here nor there.

Bradley5 said:

I would be curious how that is purchased and evaluated? Do you get foreign calcs? Are these Chinese or something more substantial like German? I think it's one thing when bringing in a high quality item. Quite another knowing full well a foreign purchase is a cost cutting tactic. As I always say, China will cut every corner they can, so then you have to go find them. But some stuff is built pretty well. Like they literally did a good job of "copying" a USA design they ripped off.

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Foreign built thin sheet silos are a pre-engineered commodity item in a highly competitive business exporting across Europe, Asia, Africa etc... North America probably has its own internal market but the rest of the world is very much global. These things are like ikea furniture but much bigger and more expensive. Getting calcs is abnormal but sometimes it can be done, but you certainly don't get a full picture. But the savings are definitely there to afford the engineering fees, so importing them and then certifying them is still an economical outcome.

To evaluate these I start from first principle and go from there. Silos are hard. But once you start getting a feel for them like all things, they become easier. One supplier accidentally sent me their Excel sheet that through a series of macros does the entire design of their silos from ~4m-12m and ~4-40m tall. That certainly made things a little easier to assess their silos once I had translated it and dissected it.

Bradley5 said:

I would be curious what approach you used to assess the PEMB? Sounds like the typical case where a building got done, then the code guy wanted papers.....?

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Straight forward calculations like I would design any building all the members were off the shelf cold formed items. I ran the calcs, found no way on each they could be justified even if you try to be clever with plastic design etc... So I made my assessment it was inadequate. And yes it was a case where the building got done and the 'guy' wanted papers. Though in this case the 'guy' was a site owned by a multinational company and knew they had screwed up by building an inadequate structure and without even getting the required permits to build. So they were more than happy to get the job done properly. (For what it was worth the structure was a medium sized maintenance shed that I'd happily have on my farm. But in no way could it meet current building codes for its intended use.)

I'm a PEMB guy and I would run. One thing you want to look for with PEMB suppliers is that they are IAS certified. It's the same as being AISC certified for a conventional fabricator. They come in a few times a year and audit your engineering, business practices, and most importantly, shop practices. In particular, how are they welding flanges to connection plates. If it's not a CJP, that will always be the failure point. If it is a CJP, does it meet AWS standards? Without that certification, someone can open up a fly by night shop and you wouldn't know.

People love to call PEMBs cheap but there's cheap and then there's CHEEEEAAAAP. Even a PEMB guy over here would likely have no way to verify the engineering design. That leaves you with one option--Hire a guy who works all over the country named Plan Stamperson to seal the job. After that, you just have to pray that they original Chinese designers knew what they were doing. Not something I would do.

SandwichEngine said:

Hire a guy who works all over the country named Plan Stamperson

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Love it. How have I not heard that one before?

SandwichEngine said:

After that, you just have to pray that they original Chinese designers knew what they were doing.

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AND it was actually fabricated per those assumed good designs. Another giant leap of faith.

AND to make this more interesting, it appears the pricing is going to be comparable, or even more expensive. IE, at least with that company, zero reason or incentive to even consider such a building with all the potential engineering questions.

Bradley5 said:

China will cut every corner they can

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There are corners left to be cut in PEMBs?

I agree with everyone else here, I wouldn't' touch it and if you did you would need to re-calculate everything and you will be hard pressed to get it to work without strengthening. We ended up on one where an owner ordered a kit online without knowing they needed foundations and needed an engineer to specify loading, thereby the whole structure arrived on site and couldn't be built nor permitted because it lacked the ability to have anything more than some lights inside the building and required gyp ceilings, fire sprinklers, mechanical and plumbing as well as stucco walls. The owner spent almost 100k to have us re-engineer and strengthen the entire building, which consisted of connection enhancements, adding columns, new walls, new lateral systems and in the end would have probably been cheaper to just order a new one designed properly.