A monumental task
BY EMMA HAAK
THE EARTHQUAKE LASTED A FEW MOMENTS.
The repair project would take almost three years and require an expert project team that could plan carefully, adjust to changes and work productively with an active client.
On 23 August 2011, the U.S. state of Virginia suffered a 5.8-magnitude earthquake—the largest to hit the U.S. East Coast in almost 70 years. It produced tremors in a third of the country and damaged buildings close to its epicenter. Among those buildings was the Washington Monument in Washington, D.C. At a height of 555 feet (169 meters), the obelisk commemorating the first U.S. president is the world's tallest freestanding stone structure.
The U.S. National Park Service, which manages the monument, had to assemble a team that could masterfully and safely repair the structure while handling the detailed, procedural nature of government projects—all as the nation watched.
“Our goal and our mantra every day was that safety was everyone's number-one priority. We were committed to providing skilled workers who would deliver the highest-quality final product. The fact that this was the Washington Monument made our focus even more pronounced,” says Robert Collie, project manager for Perini Management Services Inc., Framingham, Massachusetts, USA, which oversaw the repair phase of the project.
HOW BAD IS IT?
After an inspection team found cracks in the marble at the top of the monument, the National Park Service closed the structure indefinitely. The agency needed to assess just how much damage the earthquake had caused.
The monument from above
A month after the quake, the park service brought in a “difficult-access team”—trained to inspect locations that aren't accessible by conventional means—from Wiss, Janney, Elstner Associates Inc., a U.S. firm specializing in structural repairs. Over 10 days, the team used rappelling ropes to slowly work its way down the four sides of the monument, conducting an assessment of the damage. Using iPads equipped with information from the 1999-2000 restoration of the Washington Monument, the team differentiated between existing cracks and new ones caused by the quake.
“They rappelled down, made a visual assessment of the damage and recorded that damage area,” Mr. Collie says. “That information was transferred to a set of drawings that indicated the type, magnitude, condition and extent of the repairs that we were later contracted to do.”
While the damage was almost all cosmetic rather than structural, the difficult-access team documented over 150 cracks on the monument's exterior, including six that went all the way through the marble panels in the pyramidion, the pyramid that sits atop the monument. Those cracks were large enough to let daylight shine through. With the major damage documented, the National Park Service put the repair phase out to bid in June 2012.
“We were committed to providing skilled workers who would deliver the highest-quality final product. The fact that this was the Washington Monument made our focus even more pronounced.”
—Robert Collie, photographed in New York, New York, USA
WHILE THE DAMAGE WAS ALMOST ALL COSMETIC RATHER THAN STRUCTURAL, THE DIFFICULT-ACCESS TEAM DOCUMENTED OVER 150 CRACKS ON THE MONUMENT'S EXTERIOR, INCLUDING SIX THAT WENT ALL THE WAY THROUGH THE MARBLE PANELS IN THE PYRAMIDION, THE PYRAMID THAT SITS ATOP THE MONUMENT.
A photo taken from a helicopter shows cracks at the top of the monument.
The observation level
A team conducts the exterior assessment in September 2011.
PHOTOS COURTESY OF NATIONAL PARKS SERVICE
“Everything was of a historic nature and had to be treated with special attention and care so we would not damage the parent stone.”
Perini Management Services had experience on its side. Its parent company, Tutor Perini Corporation, was the prime contractor for the construction of the Ronald Reagan Building, the largest federal building in Washington, D.C. For the monument project, Perini submitted a thorough proposal outlining its project approach, the team it would bring together, project requirements, a scaffolding plan and an overview of how it would implement the repairs with an emphasis on its safety program.
In September 2012, the National Park Service awarded the contract to Perini—giving it US$9.6 million for the repairs, out of the total project budget of US$15 million, and a deadline of spring 2014.
DO NO HARM
Throughout the project, the team had an abiding principle: “We would do no harm,” Mr. Collie says. That meant fixing the damaged stone without causing collateral damage to the original 150-year-old stone, which is weathered and, in some places, delicate.
“Everything was of a historic nature and had to be treated with special attention and care so we would not damage the parent stone,” he says. “We had to minimize the material we had to remove of the parent stone to repair or replace.”
This sensitive work “took a higher level of expertise and skill from the masons”—and from the entire team, Mr. Collie says. That's why the project team brought in contractors who had been part of the 1999-2000 restoration project, including Grunley Construction, Lorton Stone and Universal Builders Supply.
Preparation for a crack repair
Workers put a repair in place.
In November 2012, Universal Builders Supply began to install the foundation for the extensive scaffolding—500 tons of it. By the following February, the intricate network of scaffolding began making its way up the monument's facade.
To prevent damage to the surface, the team could not simply install standard scaffolding, however. Benefiting from lessons learned during the 1999-2000 repairs—and thus shaving off design time—the team used a system similar to the one employed in the earlier project. The scaffolding stayed in place by embracing the monument with a series of compression rings, since attaching scaffolding to the monument was not an option.
“Every 26 feet [7.9 meters], there were sets of ties, and those ties squeeze the scaffolding to the monument, so there is no damage to the monument,” Mr. Collie says.
For the project team, “do no harm” had another meaning: maintaining safety, which was paramount from the start.
“With workers out on the exterior of the monument on scaffolding, certain safety precautions were put in place to make sure we didn't have any accidents,” he says.
Weekly safety meetings were held with all team members, along with monthly safety review meetings with major stakeholders, including the National Park Service, the United States Capitol Police and subcontractors. Any team members working on the exterior scaffolding had to undergo special safety training sessions, and anyone working with a potential fall hazard of over 6 feet (1.8 meters) had to be secured with a safety harness and lanyards. Finally, everyone who accessed the site was required to watch a 30-minute safety video.
In the end, these efforts paid off. “We're very pleased to say that we had no lost-time accidents on the project,” Mr. Collie says.
In May 2013, after three months, the team finished the construction of the scaffolding. Now the repair work could begin in earnest.
ON ANY GIVEN DAY, 40 TO 50 TEAM MEMBERS—FROM CARPENTERS TO MASONS TO ELECTRICIANS-WOULD BE WORKING ON THE SITE. SO THE PROJECT TEAM HAD TO CAREFULLY COORDINATE WHO WOULD BE WHERE, AND WHEN.
GETTING TO WORK
On any given day, 40 to 50 team members—from carpenters to masons to electricians—would be working on the site. So the project team had to carefully coordinate who would be where, and when. The team created drawings that indicated and numbered the work to be done by scaffolding level, elevation and monument side.
“Plus, we had daily meetings with the key foremen to communicate the work areas for each trade so we would avoid conflicts,” Mr. Collie says.
The actual extent of the quake damage also had to be addressed. Despite the difficult-access team's detailed report, its 10-day assessment couldn't identify every single instance of needed repair.
“We never really fully knew what the extent of the repairs would end up being,” he says. “We had a number of repairs that were part of the contract, but when we had the scaffolding and were able to take a closer look, additional repairs were required. We always anticipated that, but we never knew what it might entail.”
In addition to responding adeptly to such change, the project team had to factor into its schedule a detailed approval process: The National Park Service had to sign off on each type of proposed repair.
“Procedures were very detailed. And we had a group of very talented craftsmen and workers and inspectors. It was a great team approach to a great project.”
“Every repair required that a mock-up be done and inspected and approved by the National Park Service and the architect engineer,” Mr. Collie explains. “We demonstrated each repair, how we would do it, the products that would be used, the quality of the work, and how the remainder of those types of repairs would be done to maintain that high level of quality.”
These mock-ups dominated the first six weeks of the repair phase.
Once the mock-ups were approved, the team of masons from Lorton Stone got to work, starting at the monument's top 100 feet (30 meters). “That's where the result of the earthquake was magnified,” Mr. Collie says. “Because of physics, that's where you're going to get the most movement.”
The team members closed the largest cracks at the top with epoxy, an adhesive. They removed and replaced deteriorated mortar joints between panels, and they added panel anchors to help secure the pyramidion panels should another high-magnitude earthquake ever occur.
Moving down the structure, the team completed more than 150 Dutchmen repairs—instances where epoxy couldn't fix the damaged stone. The masons took photographs and prepared drawings to demonstrate the size of each piece of marble they would replace. Once that was approved, the team removed the cracked stone and replaced it with new material. Each small repair took about three days—and each one had to be approved by on-site National Park Service representatives afterward.
By October 2013, the team reached the bottom of the monument, which sustained comparatively little damage during the quake.
Because the project took place outdoors, the team had planned for weather delays, yet throughout much of the execution, the project benefited from benign weather. As project completion came within reach, that changed.
“Weather was among our number-one concerns from the start because 99 percent of the work was exterior, and it was subject to not only winds, but rain and temperature,” Mr. Collie says.
In late 2013, as the temperatures dropped, the team set up tarps and temporary heaters so work could continue, but then the weather worsened. One storm brought wind gusts of up to 60 miles (97 kilometers) per hour, sending tarps flying and forcing project work to halt for several days. To get the schedule back on track, more masons were added, workdays were extended, and some weekend work was required.
Mr. Collie credits careful planning—and a stellar team—for the project meeting its May 2014 goal: That month, the National Park Service welcomed visitors back into the monument.
“We had great documents, great drawings to rely on. Procedures were very detailed,” Mr. Collie says. “And we had a group of very talented craftsmen and workers and inspectors. It was a great team approach to a great project.” PM
Construction of the scaffolding took three months.
A team member radios her ground crew.
EACH SMALL REPAIR TOOK ABOUT THREE DAYS—AND EACH ONE HAD TO BE APPROVED BY ON-SITE NATIONAL PARK SERVICE REPRESENTATIVES BEFORE THE SCAFFOLDING COULD BE MOVED TO OTHER AREAS.
OCTOBER 2014 PM NETWORK
PM NETWORK OCTOBER 2014 WWW.PMI.ORG