Merged Applicability of Bazant's model to the real world

[beachnut]

If any engineers here can answer, in words, what NIST means by:



specifically clarifying what difference is being made between the reference to "horizontal connections" vs. the floor-to-wall connections, I would really appreciate.

If you can't, just say so, rather than implying you've "already answered the question" by posting a diagram that you can't even seem to explain. Thanks.

NIST means floor/wall disconnections occurred.

Disconnections - termination of connections

It was already answered, how did you miss it?

 

[BasqueArch]

Originally Posted by BasqueArch
What you don't calculate is the thermal expansion of the thin trusses at 700C. As they expand they buckle out of plane, largely losing their geometry and both their load carrying capacity and the horizontal bracing they previously provided to the exterior columns.

The trusses sagged more than 2" at 700C.

That's pretty good for a layperson!

The top chord will have a problem with expansion inducing additional compression in the element. Under the parameters given, it will expand about 5.8" (sorry I work in US customary). Restraint on an end will pretty much be fatal. An element that is restrained from expansion on both ends will have an induced stress of 235ksi. It will buckle long, long before then.

The web members will also expand outwards. A differential expansion of web members will cause the bottom chord to develop kinks. This will also be fatal for the truss.

Haaa. What do you expect. I was taught by two genius structural engineers in school and learn regularly from real world jobs and engineers.
Thanks for providing the math.

 

[Newtons Bit]

Single sentence excerpts in one of truthers' biggest mistakes.

Full context is necessary.

Please provide a reference to the source of this quote in NIST's reports.


tom

It's not necessary. He doesn't understand that the connection between the wall and the floor can be severed if one of two systems fail: the horizontal connections or the vertical connections.

It's a bit mind boggling.

 

[ergo]

Single sentence excerpts are one of truthers' biggest mistakes.

Full context is necessary.

Please provide a reference to the source of this quote in NIST's reports.

Have you tried reading the thread? Or even this page of it? The quote this is taken from is on this page.

 

[DGM]

Have you tried reading the thread? Or even this page of it? The quote this is taken from is on this page.

And you still don't understand.

 

[ergo]

I guess our "engineer" bedunkers are not able to distinguish between NIST's "horizontal connections" and "floor/wall" connections. Or at least they can't communicate their understanding in the form of a sentence or two.

I notice when bedunkers can't answer questions, they pose other questions that they hope will sound like answers.

 

[ergo]

.... or cryptic statements like: "And you still don't understand." in an attempt to mask their own incomprehension.

 

[DGM]

I guess our "engineer" bedunkers are not able to distinguish between NIST's "horizontal connections" and "floor/wall" connections. Or at least they can't communicate their understanding in the form of a sentence or two.

I notice when bedunkers can't answer questions, they pose other questions that they hope will sound like answers.

What part of that picture and Newtons Bit's question did you not get?

 

[ergo]

What part of that picture and Newtons Bit's question did you not get?

The part where he says: "By 'horizontal connections', NIST means _____________. By floor/wall connections, NIST means _________________. Floor/wall connections and 'horizontal connections' are therefore not the same because ____________. "

 

[DGM]

The part where he says: "By 'horizontal connections', NIST means _____________. By floor/wall connections, NIST means _________________. Floor/wall connections and 'horizontal connections' are therefore not the same because ____________. "

So you want an engineering lesson? Why are you saying NIST is wrong if you don't even understand the simply stuff?

 

[ergo]

Twenty-one posts and counting for a simple question that supposedly could have been answered on the spot by any one of you.

Fairly minor point, too.

 

[Newtons Bit]

Twenty-one posts and counting for a simple question that supposedly could have been answered on the spot by any one of you.

Fairly minor point, too.

It was already answered. But you can't grasp that there's two ways the entire connection between a floor and a wall can fail: through the vertical connections of the truss and the truss-seat or through the horizontal connections between the truss to the truss seat and the concrete deck and the rebar welded to the column.

 

[DGM]

Twenty-one posts and counting for a simple question that supposedly could have been answered on the spot by any one of you.

Fairly minor point, too.

Already done. You just don't understand the answer.

 

[ergo]

It was already answered. But you can't grasp that there's two ways the entire connection between a floor and a wall can fail: through the vertical connections of the truss and the truss-seat or through the horizontal connections between the truss to the truss seat and the concrete deck and the rebar welded to the column.

Maybe I can't "grasp" it, because you haven't stated it yet.

So, there's a vertical connection of the truss and the truss-seat. The truss rests on the truss seat and is bolted on. Is that correct? So we can call that the "floor-to-wall" connection, because the truss seat is on the column.

Then you're also saying that there is a "horizontal connection" between the truss to the truss seat again, via . . . what, exactly? And then you suggest something else about the concrete slab and the rebar being "welded to the column." I'm pretty sure you must mean something other than what you're actually saying here, right?

ETA: I think you must be saying that the truss seat is welded to the column. But this still doesn't give us an additional connection, since we've already accounted for the truss seat.

 

[beachnut]

Maybe I can't "grasp" it, because you haven't stated it yet.

So, there's a vertical connection of the truss and the truss-seat. The truss rests on the truss seat and is bolted on. Is that correct? So we can call that the "floor-to-wall" connection, because the truss seat is on the column.

Then you're also saying that there is a "horizontal connection" between the truss to the truss seat again, via . . . what, exactly? And then you suggest something else about the concrete slab and the rebar being "welded to the column." I'm pretty sure you must mean something other than what you're actually saying here, right?

ETA: I think you must be saying that the truss seat is welded to the column. But this still doesn't give us an additional connection, since we've already accounted for the truss seat.

 

[ergo]

Thanks, beachnut. I see one connection there (although we know there were the damping units on the lower frame of the truss) and I guess we could call that one connection vertical or horizontal, but I don't see a distinction between something that would be called a "horizontal connection" and then also a "floor-to-wall connection" as is suggested in the quote in question:

Floor/wall disconnections occurred by the truss walking off their seats after failure of all horizontal connections between the floor and the exterior wall, or by the vertical shear failure of truss seat, as its capacity was reduced by heat.

which, I repeat, is basically saying that "floor/wall connections failed after floor/wall connections failed..."

Which, it must be pointed out, is yet another circular argument. Kind of like (paraphrase): "the building fell in virtual free fall because it offered so little resistance to the descending mass above..." without bothering to ask why it offered so little resistance.

I am merely pointing out the lack of clarity as well as the circular argumentation evident in many of the NIST's explanations.

 

[ergo]

As well as to point out the curious use of the word "all" in that quote.

after failure of all horizontal connections between the floor and the exterior wall ...

 

[Newtons Bit]

As well as to point out the curious use of the word "all" in that quote.

1) Bolts in long-slotted holes from truss to truss-seat.
2) Gusset from column to truss.
3) Rebar welded onto the columns and developed into the concrete slab (not in a picture posted).

Curious, huh?

 

[beachnut]

... it offered so little resistance ...

What does 911 truth call a floor that can hold up to 29,000,000 pounds? (like 29 million pounds)

little resistance!

Do you make up these definitions as you go, or does Gage hand them out when you join his spread the lies travel club?

 

[ergo]

1) Bolts in long-slotted holes from truss to truss-seat.
2) Gusset from column to truss.
3) Rebar welded onto the columns and developed into the concrete slab (not in a picture posted).

Curious, huh?

Yes, curious. So now I understand the welded gusset plates and the bolted truss to truss-seats. Still not clear on how either of these could be distinguished as a "horizontal connection" versus a "floor/wall connection", since they are both obviously both. But I think I've made my point and won't belabour it.

What is interesting is your statement about the rebar from the concrete slabs welded onto the columns. I did not know about this. Is this common knowledge?