ᐅ Glued laminated timber beam (GLT) / orientation of the laminations

hanghaus2023 schrieb:

This was already discussed back in 2019. Unfortunately, posting links is not allowed here. I used Google once.

"Is it a problem if BSH purlins are installed incorrectly?"

First result.

Thanks, hanghaus2023,
I found it and it reassures me.

alive&kicking schrieb:

Yes, this is really OUR site manager, commissioned for work stages 5 - 8 and structural engineering, paid by us.

So also covered by professional liability insurance. Where does the unusual scope of mandate "second half" come from?

In der Ruine schrieb:

This can’t be compared to a leaf spring either. It’s so flexible because the layers are loose and can slide against each other when bending. BSH shouldn’t do that.

Got me – it’s an imperfect comparison, since here we are dealing with a fully rigid, “non-springing spring.”

alive&kicking schrieb:

The foot purlins are made of concrete, the ridge purlin is BSH, positioned vertically [ / ] the two intermediate purlins have the same function.

…but do they also have the same orientation (that was my question)?

alive&kicking schrieb:

A square is a square, right? What would be the correct designation for BSH when all sides of the purlin have the same length?

“Right.” We’re not talking about irregular shapes where it doesn’t matter how the outer shape fits together.

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11ant schrieb:

So it also includes professional liability insurance. Where does the unusual mandate scope "second half" come from?

I’m sorry, I don’t understand the question. What is unusual about the scope when building with individual trades instead of a general contractor?

11ant schrieb:

... but do they also have the same orientation (that was my question)?

No, they don’t, otherwise I wouldn’t have noticed.

alive&kicking schrieb:

No, they didn’t, otherwise I would have noticed.

Then one of the two is oriented incorrectly. Since they have the same task to perform, this leads—even if the difference in orientation is considered minor—to an uneven or skewed distribution of the loads they need to carry, which a designer (for a symmetrical roof) would not have planned. So the workers probably took the approach of "it’s (supposedly) irrelevant when it comes to a square" and handled it arbitrarily. Since you mentioned there was also a design phase 5, I would suggest checking which orientation the plan actually specifies.
In structural engineering, there is no such thing as "almost irrelevant"; the calculations will have been done for one orientation or the other.

alive&kicking schrieb:

Unfortunately, I don’t understand the question. What is unusual about dividing the work by separate trades instead of using a general contractor?

In turn, I don’t understand what this has to do with separate or general contracting. What is unusual is bundling design phases 5 to 8. Having design phase 5 performed by someone who was not at least significantly involved in design phase 3 is a task only for someone who has “killed both parents.” That’s why I use my saying "3 + 5 = 8" to emphasize that the “parentage” of design, detailed planning, and construction management should be held by the same party. So, bundling design phases 5 to 8 is not a good "package," but rather the "remaining unfinished part" if someone previously chose the (also bad) package "design phases 1 to 4." For more on this, see my post on Bauen jetzt titled "A building schedule for you too: the HOAI phase model!"

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11ant schrieb:

Then one of the two is incorrectly oriented. Since they have the same task to handle, this leads— even if the difference in orientation may seem minor— to an uneven or skewed distribution of the loads they have to carry, which a designer (with a symmetrical roof) would not have planned for. So the workers probably took the “it’s (supposedly) the same for a square” approach and handled it according to preference. Since you mention there was also a design phase 5, I would check which orientation the plan actually specifies.
In structural engineering, there is no such thing as “almost doesn’t matter”; calculations are always done for one orientation or the other.

Thanks for this insight, I’ll keep it in mind and discuss it with the structural engineer we hired. However, I’m pretty sure I won’t find that orientation specified in his plans, and not because I wouldn’t recognize it.

11ant schrieb:

I don’t understand how this relates to individual or overall contracting. It is unusual to combine phases 5 through 8. Phase 5 should be handled by someone who was at least significantly involved in phase 3; otherwise, it’s a task for someone totally unfamiliar with the previous work. That’s why I always say “3 + 5 = 8” to stress that design, detailed planning, and construction management should be handled by the same party. So “phases 5 to 8” is not a good package—it’s just the “unfinished remainder” if someone chose the (also poor) package “phases 1 to 4” before. For more, see my article “A Home Building Roadmap, also for you: the HOAI phase model!” on Bauen jetzt.

Yes, that makes sense... now I understand what you mean.

Unfortunately, it’s too late, but the architect who did the design phase did not want to take on construction management... otherwise, things probably would have gone more smoothly.


off topic
What is your opinion about professional associations or expert groups?
We chose our structural engineer partly because, in addition to being a member of the engineering chamber, he belongs to two professional associations and stated he works as an expert and appraiser—that was a quality seal for us.

In hindsight, I wonder how someone with so little expertise and passion for their work can hold such positions. I could list maybe 40–50 examples.
How is one supposed to navigate this? Where should you look when trying to find an expert who will just build a perfectly ordinary house?

alive&kicking schrieb:

Thanks for this insight, I’ll keep it in mind and discuss it with the structural engineer I hire.
However, I’m now quite confident that I wouldn’t find this orientation in their plans—and not because I wouldn’t recognize it.

Well, hopefully the planner didn’t just go through phase 5 of the service phases for the fee share. Whether the construction workers (no coincidence in the name, they are definitely not tree thinkers) would have even read such a note in the plans is also doubtful.

alive&kicking schrieb:

How is one supposed to orient oneself here, where should someone look when they want to find an expert who just builds a completely ordinary house?

Experts like that are better avoided; I’d recommend going to specialists like me or one of my quite a few colleagues. Then you’ll also know who is better avoided:

alive&kicking schrieb:

Sadly too late now, but the architect of the design phase didn’t want to take on the construction execution ... then everything probably would have gone better.

I’ve already written here several times that you can often “spot” architects warned by @Gerddieter because they prefer to offer the scope of work “phases 1 to 4” aka the first half. Allowing such an architect to handle the second half as well is not “unfortunately” but “thank God” too late, since they usually mess it up in every way except honorably. In that sense, be glad you avoided that cup being poured over you. However, it was probably an unwise idea to switch from one amateur to another. Do you even have a “completely ordinary house”?—I don’t recall you having shown it here yet.

alive&kicking schrieb:

off topic
What is your opinion of the expert associations or societies?
When we chose our structural engineer back then, he belonged not only to the Chamber of Engineers but also to two “professional associations” and stated that he works as an expert and appraiser? For us, a seal of quality.

This is by no means off topic. The answer is: keep your distance. 11ant understands far less about bananas than monkeys do, yet I could probably found a banana association myself. Association memberships are more like carnival badges as a “seal of quality.” Narrow-minded so-called experts like to band together in associations mainly to share a lawyer against claims questioning their competence and to lobby against efforts to raise quality standards for their services. Membership in the Chamber of Engineers is mandatory for the license to practice, just as a corresponding liability insurance is essential. Chambers operate within jurisdictional districts. Their members would need to move residence if they find their chamber’s work insufficiently committed. This is also a reason for the existence of the good voluntary associations.

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