Kai Kostack's WTC7 Collapse Simulation using BCB and Blender

[Abdullah]

Should this have been found to be point of failure during the design? If so, how would engineers determine that?

Yep. It would go like this:
Hmmm we got several columns connected by nothing but floor beams.
1.There's no way the floor system has the vertical rigidity to redistribute loads beyond the closest column. That's not good because if all gravity loads from these here columns were shifted to the immediate neighbors, they would be overloaded and fail and repeat Not very redundant.
2.also, are we sure the beams won't just disconnect snd collapse? Taking everything and everyone on them? Even if that doesn't trigger some chain reaction, it will itself be horrific

 

[Gamolon]

You're missing the point. If a plane had flown into WTC7 and severed just a few columns, thousands could have died within seconds.

As an engineering firm, how one determine if a building is safe from ANY permutation of certain structural member damage within the entire structure causing complete collapse?

Where do you stop?

Doing computer simulations of different size planes flying into 1 column? 2 columns? 3 columns? X number of columns? On every floor? Ort maybe columns 1, 5 and 6 fail due to fire on floor 3? Bombs?

Can any engineering firm 100% guarantee that they've analyzed every possible scenario and that their building will NEVER collapse under any circumstance?

How is that possible?

 

[Abdullah]

As an engineering firm, how one determine if a building is safe from ANY permutation of certain structural member damage within the entire structure causing complete collapse?

I'm not sure what you're asking here.

Where do you stop?

You write as if the vulnerabilities need complex computer simulation to even cincieve of. I have made the counter argument in my previous reply.

 

[FatPhil]

Nor is it to hijack four planes and fly them to three different locations.

However, we have well-attested evidence that precisely that happened. Metabunk is about debunking claims of evidence. There is no evidence for the claim that you are lining up as an alternative to the above. There is no parallelism between them, they are not equals.

 

[Gamolon]

Yep. It would go like this:
Hmmm we got several columns connected by nothing but floor beams.
1.There's no way the floor system has the vertical rigidity to redistribute loads beyond the closest column. That's not good because if all gravity loads from these here columns were shifted to the immediate neighbors, they would be overloaded and fail and repeat Not very redundant.
2.also, are we sure the beams won't just disconnect snd collapse? Taking everything and everyone on them? Even if that doesn't trigger some chain reaction, it will itself be horrific

1. Are you expecting the structural engineering designing a structure to due simulations for every possible failure scenario? Example:
Column 1 (of 24) is severed at floor 1 (of 47). Percentage of building collapse.
Column 2 (of 24) is severed at floor 1 (of 47). Percentage of building collapse?
Columns 1 and 2 are severed at floor 1 (of 47). Percentage or building collapse?
Columns 6 and 8 (of 24) are weakened by 15% from fire on floor 23 (of 47)

Etc...

2. Disconnect due to what? Bombs? Fire? Static loads? Dynamic loads? Each scenario is different and would need to be "beefed up" to deal with whichever stresses each scenario presented to them?

Etc...

 

[Gamolon]

I'm not sure what you're asking here.


You write as if the vulnerabilities need complex computer simulation to even cincieve of. I have made the counter argument in my previous reply.

See my post above.

 

[Gamolon]

I'm not sure what you're asking here.

What you're asking is to have a structural engineer go through every possible structural damage scenario and make sure that the structure is 100% invincible to total collapse.

 

[Gamolon]

You write as if the vulnerabilities need complex computer simulation to even cincieve of. I have made the counter argument in my previous reply.

Below are some explanations from NIST on what possibly happened. Are you saying that the engineer/s responsible for the structural design of WTC7 should have foreseen these possible scenarios and recognized that WTC7 would completely collapse and then "fix the failure points"?

"Factors contributing to WTC 7's collapse included: the thermal expansion of building elements such as floor beams and girders, which occurred at temperatures hundreds of degrees below those typically considered in current practice for fire-resistance ratings; significant magnification of thermal expansion effects due to the long-span floors in the building; connections between structural elements that were designed to resist the vertical forces of gravity, not the thermally induced horizontal or lateral loads; and an overall structural system not designed to prevent fire-induced progressive collapse."

"The heat from the uncontrolled fires caused steel floor beams and girders to thermally expand, leading to a chain of events that caused a key structural column to fail. The failure of this structural column then initiated a fire-induced progressive collapse of the entire building.

According to the report's probable collapse sequence, heat from the uncontrolled fires caused thermal expansion of the steel beams on the lower floors of the east side of WTC 7, damaging the floor framing on multiple floors.

Eventually, a girder on Floor 13 lost its connection to a critical column, Column 79, that provided support for the long floor spans on the east side of the building (see Diagram 1). The displaced girder and other local fire-induced damage caused Floor 13 to collapse, beginning a cascade of floor failures down to the 5th floor. Many of these floors had already been at least partially weakened by the fires in the vicinity of Column 79. This collapse of floors left Column 79 insufficiently supported in the east-west direction over nine stories.

The unsupported Column 79 then buckled and triggered an upward progression of floor system failures that reached the building's east penthouse. What followed in rapid succession was a series of structural failures. Failure first occurred all the way to the roof line-involving all three interior columns on the easternmost side of the building (79, 80, 81). Then, progressing from east to west across WTC 7, all of the columns failed in the core of the building (58 through 78). Finally, the entire façade collapsed."

 

[benthamitemetric]

As I already pointed out, many building codes do now require that tall buildings be designed with extra resiliency to specific possible progressive collapse scenarios. The Key Element Analysis process in Chapter 16 of the NYC building code is an example of how this can be required in practice. Will that prevent every possible progressive collapse scenario? No. As Gamolon and Mendel have pointed out, there are of course going to be trade offs involved in such engineering requirements, just as there are in car safety standards, air plane design/testing requirements, drug trials, etc. Too much precaution/regulation may only marginally reduce risk while greatly increasing costs and lowering productivity gains, leaving people worse off than if there were less regulation. We live in a material world where bad things can and do happen to humans, which are squishy imperfect biological beings, and there will thus always be some risk in human endeavors, after all.

If Abdullah thinks he can come up with a superior set of building requirements than those that are currently in the building codes, then I think his time would be better spent advocating for those with the relevant professional councils that oversee such codes. So far, however, he has yet to put forward concrete proposals to that end in this thread (in fact, it does not seem like he is even aware of what the current codes require), and, even if he could, I don't see why those recommendations would belong in this thread on the topic of Kai Kostack's WTC7 modeling experiment. In any case, as a group of laypeople, I don't think it is likely we are going to debate our way to a resolution on a superior system here, so I really only see pages and pages of circular discussions that go nowhere if the thread follows its current course.

 

[Mick West]

Precisely. The failure to condemn this glaring flaw and make a scandal out of it is one of the biggest drivers of skepticism. It needs to be said: Building 7 was a dusaster waiting to happen.

What point are you trying to make?

This thread is for discussion of Kostack's model, not building codes.

 

[Abdullah]

@Mick West I apologize for driving this thread offtopic.