Masonry Magazine August 2002 Page. 41
The renovation project worked within the existing exterior walls. Once the interior walls were removed, Masonry Arts found the evidence of the rapid construction the building had undergone in 1942.
gy efficiency of the building but will also serve to protect the tenants against an external attack. Steel beams reinforce the walls around the new blast resistant units. Each window unit weighs approximately 1,600 pounds. The geo-technical material covering the wall between the steel beams acts as a giant 'catcher's mitt' in the event of an explosion, preventing debris from causing injury to the occupants of the room."
Rich Bartram, Masonry Arts' supervisor for the PenRen project adds, "We originally did the steel back up in the blast wall system and the blast windows for Wedge 1 where the September 11 impact occurred. Our blast wall, and the steel stacks from the first to the fifth floor, has everything connected with bolts through the slabs and with steel plates sandwiching the slabs. That blast steel allowed the façade at floors three through five, to stand for 35 to 40 minutes after the plane initially came in, allowing several dozen people to get out of the building."
In other words, it worked the way it was supposed to. Bartram talks about one of the things that happened that fateful day, "We have an e-mail from a general whose office was on the third floor directly above where the plane came in. His back was about one foot from the window. He got thrown through his office and then through another door. Immediately, the whole floor filled with smoke. He crawled out and saved five other people on the way down. He was able to go up to the fifth floor to see who he could find, and then he worked his way down and come right out the Corridor 4 door before that façade collapsed."
Even though Masonry Arts specializes in security work-they have done work for U.S. embassies in countries such as Kenya and Russia-they don't always have access to the details on how and why the government designs its facilities. As Bartram says, "We know the blast load the window will take. We fabricated and installed the steel at the direction of blast engineers who work for the government. We don't know the intent of this steel, whether it's intended to prevent progressive collapse or not. That's a top secret of the government. All we know is the force the window had to take in order to design the window and the transfer brackets."
The renovation project worked within the existing exterior walls. Once the interior walls were removed, Masonry Arts found the evidence of the rapid construction the building had undergone in 1942. The original windows had been secured in brick with a lot of grouting to even things up. Because the new work had to exist in the same space, with no visible difference
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The Voice of the Mason Contractor
August 2002
Masonry
39