Lafayette Building's top two floors subsiding?

**ghettopalmetto** · July-22-09, 07:36 AM

Originally Posted by davewindsor

No, my conclusions aren't clouded. Depending on what the engineer reports say or don't and the conclusions they reach determine if the lender will give me financing. Banks don't just throw money at bad reports. If they did, there wouldn't be a need for a structural report to begin with. So, I understand what's in the report and the impact it'll have.

Engineers may have differing opinions, but unlike you, I am obligated to base my professional opinions on facts and objective information. You simply don't have a knowledge of even the most fundamental engineering principles, as evidenced by your ramblings.

I sure hope the reports you purchase are signed and sealed.

Originally Posted by davewindsor

You say what I write is idiotic, yet an engineer passed WTC 7 or it wouldn't have been built. Yet, WTC 7 built in the 1980's collapsed without being struck by a plane while neighbouring buildings 5 times the age all remained standing. So who's the idiot? I guess I shouldn't be concerned for my safety after seeing the kind of crap and unsafe buildings engineers now pass because if I don't blindly trust your opinion I'm an idiot. Sounds like an idiotic conclusion to me.

Engineers don't "pass" buildings--they design them. Their seal and signature upon the design documents represents a standard of care the engineer-in-charge is required to meet, which includes, among other things, adhering to building codes and sound engineering practice. A seal and signature indicates a hell of a lot more commitment to protecting life safety than your paranoid off-the-cuff ramblings.

You think newer buildings are unsafe as-constructed? Prove it. Demonstrate, using calculations and engineering principles, that WTC 7 was designed to be an unsafe building.

I don't have any direct knowledge of WTC 7 construction, so I have to rely on third-party information. You can read this summary from Popular Mechanics, which cites NIST investigations. But I'm sure your extensive background in reading reports couched in laymen's language is far superior than any Professional Engineer engaged by NIST.

http://www.popularmechanics.com/tech...42.html?page=5

Many conspiracy theorists point to FEMA's preliminary report, which said there was relatively light damage to WTC 7 prior to its collapse. With the benefit of more time and resources, NIST researchers now support the working hypothesis that WTC 7 was far more compromised by falling debris than the FEMA report indicated. "The most important thing we found was that there was, in fact, physical damage to the south face of building 7," NIST's Sunder tells PM. "On about a third of the face to the center and to the bottom — approximately 10 stories — about 25 percent of the depth of the building was scooped out." NIST also discovered previously undocumented damage to WTC 7's upper stories and its southwest corner.

NIST investigators believe a combination of intense fire and severe structural damage contributed to the collapse, though assigning the exact proportion requires more research. But NIST's analysis suggests the fall of WTC 7 was an example of "progressive collapse," a process in which the failure of parts of a structure ultimately creates strains that cause the entire building to come down. Videos of the fall of WTC 7 show cracks, or "kinks," in the building's facade just before the two penthouses disappeared into the structure, one after the other. The entire building fell in on itself, with the slumping east side of the structure pulling down the west side in a diagonal collapse.

According to NIST, there was one primary reason for the building's failure: In an unusual design, the columns near the visible kinks were carrying exceptionally large loads, roughly 2000 sq. ft. of floor area for each floor. "What our preliminary analysis has shown is that if you take out just one column on one of the lower floors," Sunder notes, "it could cause a vertical progression of collapse so that the entire section comes down."

There are two other possible contributing factors still under investigation: First, trusses on the fifth and seventh floors were designed to transfer loads from one set of columns to another. With columns on the south face apparently damaged, high stresses would likely have been communicated to columns on the building's other faces, thereby exceeding their load-bearing capacities.

Second, a fifth-floor fire burned for up to 7 hours. "There was no firefighting in WTC 7," Sunder says. Investigators believe the fire was fed by tanks of diesel fuel that many tenants used to run emergency generators. Most tanks throughout the building were fairly small, but a generator on the fifth floor was connected to a large tank in the basement via a pressurized line. Says Sunder: "Our current working hypothesis is that this pressurized line was supplying fuel [to the fire] for a long period of time."

WTC 7 might have withstood the physical damage it received, or the fire that burned for hours, but those combined factors — along with the building's unusual construction — were enough to set off the chain-reaction collapse.