Masonry Magazine August 2002 Page. 42
Pentagon Renovation Program
SERIES
On the outside of the limestone façade, much of that old work had to be redone in the same manner.
Roy Swindal, Masonry Arts' president, says, "We grouted from the brick back up to the window, then to the steel reinforcement. We grouted everything solid to the wall. The blast-resistant windows are designed to take a certain intensity of blast and to minimize damage to people inside the building in much the same way."
Making the window to resist blast pressure was only part of the problem. The original ones were operable-they could be opened for ventilation-but blast windows are not or they would immediately lose their capability to withstand an explosion. They must have all the same features on the outside, complete with the pull handle, because those are all historic features. When Masonry Arts experts went around checking the original windows to replicate them, some things were recreated without even knowing why the original feature existed.
"If you look close, you'll see little tabs in the corners, on the upper lights," says Swindal. "Nobody knew what those were. One day, when we were taking the Capitol Architect around, he said, 'What do you think those are?' I said, 'I think they were tabs to hold the screens.' He replied, "That's exactly what they are."
"We didn't know what they were, we just knew they had to be on the window," Swindal admits.
Obviously, there were other changes made, but they are not obvious from the outside of the building. Swindal recalls, "When we started on Wedge 1, on the heliport side, if a helicopter landed, with all the original windows closed, you couldn't stand next to each other and talk, you couldn't hear. With the blast windows in place, people commented that the only way you know the helicopter is even out there is when you see the blades turning. You can't hear them at all."
The PenRen Program is a multi-year project, larger and more costly, not to mention more time consuming, than the original construction which only took 16 months. The work done so far shows the value of the project and where priorities can be placed. "If the aircraft had hit on the other side of the building, in a wedge that hadn't been renovated as Wedge 1 had been, it would have been a lot worse," Swindal cautions. "The experts say the plane might have come out the other side of "A" Ring, into the center courtyard."
Bartram notes, "The plane hit in an almost perfect spot to prevent even greater loss of life. What you saw collapse was an expansion joint that it hit. When it knocked out all the columns on the first floor, the rest of the building held for about 35 minutes and then it collapsed. We feel that if it hadn't hit that expansion joint, there would have been a hole in the first and second floor and that would have been it. The third, fourth and fifth floors would have stood."
Government engineers and Masonry Arts installers can take pride in accomplishing what they set out to do, making the building safer for its occupants in case of an attack. Unfortunately, the proof of concept of the PenRen project happened on September 11. The official report of the attack states:
"Three measures taken during the renovation of Wedge 1 to reinforce the inner and outer walls served to dramatically slow the plane as it entered the building, reduced the extent to which it penetrated the rings, and prevented the immediate collapse of the structure directly above the area of impact. Despite the tremendous impact of the plane and the fire that was fed by the plane's fuel, the 'web' created by the blast-resistant windows, steel columns, and geo-technical mesh, held the building together for 35 minutes, giving many Pentagon employees, some located directly above the area of impact, time to escape.
"The Pentagon Renovation Program received numerous accounts from personnel located in renovated areas directly above or adjacent to the area of penetration. Many of these personnel were standing directly in front of or close to the new blast-resistant windows. Most of the new units remained intact and prevented severe injuries and possible loss of life. However, old window units in Wedge 2, up to 200 feet away, blew out during the initial impact and explosion of jet fuel."
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