Rebuilding the Pentagon

The traumatic events of Sept. 11, 2001, will be forever burned into our lives and history books. The hijaking and subsequent crashing of jumbo jets into the World Trade Center, the Pentagon and near Pittsburgh yielded tremendous tragedy. But at the Pentagon, it could have been worse.

by Clair Urbain

Based on Pentagon press conferences and Department of Defense reports, when the Boeing 757 crashed into the side of the Pentagon, the terrorists steered the aircraft into a newly-renovated area. Press reports peg the plane speed at 345 mph.

“It was 99 percent complete,” says Lee Benish, of AMEC, the contractor responsible for the Pentagon Wedge 1 renovation. The company is now helping with recovery operations and will play a key role rebuilding the renovated area.

The Pentagon is made up of five chevron-shaped units that have five distinct rows of office space that are all five stories high.

The aircraft also took out a section of Wedge 2, an area scheduled for renovation this year, says Walker Lee Evey, Pentagon renovation manager.

The contrast of the damage between the two wedges is dramatic.

“This was a terrible tragedy and people lost their lives, but if we had not undertaken this effort in the building, this could have been much, much worse,” says Evey, who oversees the nearly $1 billion renovation that started in 1999.

Two of Evey’s staff were on the fifth floor of the outermost ring of Wedge 1, about 50' down the corridor from where the plane entered the building. In the renovated area, the workers crawled on their hands and knees and checked every office, from the fifth floor to the second floor, to make sure anyone who survived could get out.

“They couldn’t get to the first floor so they crawled out of the building at that point. This structure held. It did not collapse for 30 or 35 minutes. It gave them the time to do that and it gave people in the building time to escape the area. We believe that the effect of the structure was to dramatically slow the plane as it entered the building and reduce the extent to which it penetrated the building,” he says. The nose of the plane almost made it to the innermost circle of the complex. Approximately 3,500 people work in the damaged area; 189 lost their lives.

Renovation sorely needed
After nearly six decades of operation, wear and tear has taken its own toll on the Pentagon. The utilities are past their useful lives and the utility distribution system and plumbing cause ongoing maintenance and safety problems. Ventilation systems are inadequate and the last time the building met electrical code requirements was in 1953, says Evey.

Over the years, communications systems were piggybacked onto old systems, resulting in a confusing, poorly documented bundle of wires. Exterior areas of the building are also deteriorating, and asbestos, lead paint, mercury and PCB contamination throughout the building make any maintenance job difficult and expensive.

Plans were laid in 1990 to renovate the complex.

“I think everyone at some point became aware that our world over the past years has changed in very dramatic ways and we thought the prudent thing to do was to recognize that change and take appropriate steps. We looked at things like the characteristics of the blast to which the building might be subjected in a terrorist event,” Evey says.

“No building can be perfectly safe. No building can be blast-proof. It can’t be built,” he says.

The first step taken to improve security was to move all deliveries to a remote facility at the north end of the building. “The purpose of that facility is to move truck deliveries, which used to come right in the south end of the Pentagon, away from the building. Eighteen-wheelers used to back up inside the building on the loop itself to unload. This was clearly a tremendous threat,” says Evey.

The new 250,000 sq.-ft. facility has been open for just over one year. Once a truck enters the facility, bomb-sniffing dogs check out the truck and security officers check under the chassis with mirrors. Everything coming into the Pentagon is examined with pallet-sized X-ray machines. “After it is checked, it does not leave the cleared area. It goes through a tunnel to the Pentagon,” he says.

Bus traffic is also now rerouted to a new Metro station farther away from the building. “Buses came within 9' of the building. Clearly, this was something we had to do to help protect the building,” Evey adds. The building is further protected by an extensive monitoring and control system through the new Building Operations and Control Center.

The exterior high-pressure water lines have also been replaced. “It doesn’t sound like a safety or security issue, but the last time we had a significant fire in the Pentagon happened to be on the date aircraft were going in for their first air strikes on Desert Storm,” recalls Evey.

A fire broke out in the basement. When the fire department hooked up the hoses and turned on the water, the pipes blew and more than nine million gallons of water flowed into the basement. If the water rose a few more inches, the Air Force Operations Center would have gone off-line as aircraft were going in on their initial strikes, he says.

Logistics
More than 25,000 civilian and military personnel work in the building; 20,000 personnel must be relocated or worked around at some point of the renovation process. All building systems must remain operational, and accessible on all sides and security maintained.

The building was built in five distinct sections, or wedges, and that’s how renovation will proceed. “The Pentagon was constructed in five chevron shapes. Each of the chevrons was built almost as a stand-alone building. Each has its own utility system that is separate from the utility systems on either side. That enables us to build a construction wall, move people out, shut down the utilities and continue operating the rest of the building,” Evey says.

New from the inside out
Each wedge has over one million sq.-ft. in office space.

Before the Wedge 1 renovation started, other work had to be completed. The heating and refrigeration plant was replaced with an energy-efficient system that offers redundancy. Crews also removed 45,000 cu. yd. of soil from the basement of the building and drove additional pilings. A new slab and raised flooring provides greater flexibility and accessibility of the space.

Wedge renovation starts with relocating workers, then stripping the internal structure.

From there, the building’s poured concrete frame is reinforced with 6" x 6" steel beams.

“The steel beams start on the first floor and go though to the fifth floor. They’re bolted together floor-to-floor so it is one continuous unit,” says Evey.

Preserving the look
The renovated areas have new windows that match the stripped neoclassical design of the building, a requirement of the building being on the National Register of Historic Places. The window design preserves the look of the original building, but is built to take a much greater blast impact. The glass in the blast-resistant windows is almost 2" thick. More than 1,500 windows were replaced in Wedge 1 renovation.

The Army Corps of Engineers helped develop the steel framework that goes around each window to offer improved blast protection. Each blast-resistant window system weighs 2,500 lbs.

In the attack, many of the new blast-resistant windows did not shatter despite the enormous pressure placed on them, Evey reports. Conversely, many of the old windows in the unrenovated Wedge 2 area were shattered, even at great distances from the point of impact.

White Kevlar fabric installed between the frame’s exterior and the building skin provides additional protection.

“That’s the same stuff found in bullet-proof vests. We interspersed it between the steel beams and the windows to catch any fragments that would result from a blast event,” he says.

“From evidence in the area, we believe this structure dramatically slowed the plane as it entered the building and reduced the extent to which it penetrated it,” Evey says.

“As the plane entered the building, it sheared off or severely damaged supporting columns. What held up a portion of the building are the steel columns we put in. Had it not been for them, you would have had a much larger collapse and perhaps many more casualties,” Evey says.

Fire sprinklers were also installed in the Wedge 1 renovation. “There was a fire that raged through Wedge 2, the unrenovated area. If you look at Wedge 1, except in areas where it was clearly fueled by jet fuel, the fire was knocked down by the fire sprinklers. There was no spread whatsoever,” he says.

Change in acquisition process
The Pentagon’s new attitude includes a new thought process on contract work. Long driven by a low-bid philosophy, the Pentagon will use design-build concepts for Wedge 2 through 5 renovations.

“We wanted to go about our work in a different way. Wedge 1 was built in the traditional manner where you hire an architectural engineer who does designs, drawings and specifications for you. For Wedge 1, that set of drawings was 3,500 pages. It’s very elaborate.

“After you have those drawings and specifications done, you put the package out for a bid and you get a contractor to build to what the drawings say. What we are doing with Wedges 2 through 5 is called design-build. We hire the architect/engineer and construction contractor as one package and they work as a team. It dramatically reduces the number of specifications and drawings that we provide. We ask them to provide a certain output product that we call a performance specification,” he says.

In contrast to the 3,500 pages of documentation for the design-bid-build process, Evey says the documentation for the design-build process for Wedges 2 through 5 is only 16 pages. “We have done it several times in the Pentagon renovation. It saves taxpayers money. It saves us time,” he says.

Wedge 1 renovation begins again
Rebuilding Wedge 1 will continue under AMEC, the present contractor. The Wedge 2 through 5 renovation will proceed as planned by Hensel Phelps Construction Co., says Evey. “The initial value for Wedges 2 through 5 is $145 million, which is the monies we have available this year. The total potential value is $758 million,” he says. It does not include the funds needed to bring Wedge 1 back to its pre-bombed status.

Published in the November/December 2001 issue of Contractor Tools and Supplies magazine.

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