have you ever been inside the pentagon and touched a wall? what was the wall reinforced with and why? could it be they were making it more sound proof because of the helos landing there all the time? have you ever even been to the area yourself?
google it.
The Pentagon Renovations
Completed on 9/11/2001
A year’s work finally finished. Dan Fraunfelter counted himself lucky when he landed a job working on the first phase of the massive Pentagon renovation project. When the military complex was originally built, it was constructed in five, chevron-shaped wedges. Each chevron, more than 1 million square feet in size, accommodating roughly 5,000 workers, was designed as a stand-alone building with its own separate utility system. The unique design was meant to make the entire complex stronger (if one section of the building was suddenly disabled, the others could function regularly without disruption.)
But it also lent itself particularly well to renovation. Even though the Pentagon is massive—larger than three Empire State Buildings, the face on each of the five sides slightly longer than three football fields— the wedge construction allowed engineers to remake the building one, easy-to-close-off section at a time. Contractors could simply move workers, seal off a wedge, and install new features like reinforced steel columns and two-inch-thick blast-resistant windows. Fraunfelter, a 24-year-old who studies architecture part time at Northern Virginia Community College, had long been fascinated by the Pentagon. When his firm, Amec Construction, won the general contract for Wedge 1, he plunged into the job eagerly, anxious to explore every square inch of the physical structure.
On Sept. 11, the contract officially complete, Fraunfelter was finishing up a few last punch-list items. He arrived on-site at 7 a.m. to prepare for an 8 a.m. tenant meeting. It was a routine job-completion task, a meeting where tenants handed over a list of final fix-it items: touch-up painting, leaking pipes, etc. [MSNBC]
American Airlines Flight 77 struck the portion of the building that had already been renovated. It was the only area of the Pentagon with a sprinkler system, and it had been reconstructed with a web of steel columns and bars to withstand bomb blasts. The steel reinforcement, bolted together to form a continuous structure through all of the Pentagon's five floors, kept that section of the building from collapsing for 30 minutes--enough time for hundreds of people to crawl out to safety.
The area struck by the plane also had blast-resistant windows--2 inches thick and 2,500 pounds each--that stayed intact during the crash and fire. It had fire doors that opened automatically and newly built exits that allowed people to get out.
"This was a terrible tragedy, but I'm here to tell you that if we had not undertaken these efforts in the building, this could have been much, much worse," Evey said. "The fact that they happened to hit an area that we had built so sturdily was a wonderful gift."
The rest of the Pentagon would not have fared as well.
The fire that swept through the building caused the greatest damage in an unrenovated section with no sprinkler system, heavy windows or steel reinforcements. But many of the offices there were empty in anticipation of the renovation.
While perhaps 4,500 people normally would have been working in the hardest-hit areas, because of the renovation work only about 800 were there Tuesday, officials said. [LATimes]
Most of Marine Aviation had just the weekend before been moved to the "Butler building," an extension of the Pentagon and about 200 yards from where the impact occurred, not nearly as close as their previous offices. [mca-marines.org]
