Industrial radiography is regulated by the Washington, D.C.-based U.S. Nuclear Regulatory Commission and individual state’s departments of environment. Radiographers are certified by the American Society for Nondestructive Testing, Columbus, Ohio, and must be licensed and complete continuing education to maintain that license. In addition, radiographers, who wear radioactivity monitors on their person, follow strict safety guidelines onsite. “We completely rope off the area and make sure all personnel who aren’t trained are out of the area,” Dugan notes. “We do an actual eyes-on walkthrough on every job before each and every exposure to make sure nobody’s inside that building before we make an exposure.”
After its site work was complete, Dugan’s team provided digital images to the engineering firm. Again, similar to a radiologist in a hospital, TÜV Rheinland simply made the exposures available and explained to Taylor and his team what the exposures showed. “TÜV was not the determining party for rejection or acceptance of the images,” Dugan adds. “The final repair analysis rested with Taylor Structural Engineers.”
Surprising Results
When it comes to construction, radiography most commonly is used on infrastructure—bridges, power plants, water towers and more. Although the Block House was a unique project for TÜV Rheinland’s team, it didn’t create any special challenges. However, the team took the age of the structure into consideration. “We did everything in slow motion just to make sure we didn’t disturb anything,” Dugan says.
Despite the building’s age, when the exposures were revealed, Taylor was startled by the results. “I was a little bit surprised there was not as much deterioration as I had anticipated,” he recalls. “I expected to see a lot of rotted wood throughout, but it really wasn’t as bad as I thought it would be.”
Based on the results of the X-ray, Taylor determined damage was occurring to the wood from the exterior parts of the building. To correct these issues, structural epoxy will be injected into sections of the timbers where internal voids have developed from wood decay; several small sections of the timbers where extensive deterioration occurred will be replaced; sealant will be applied at several open joints where existing sealant is badly deteriorated; and reinforcing steel will be installed to strengthen a failing corner section. The wooden gun loops also will be treated with a borate-based preservative to further protect the area from water and insect damage.
As the preservation and restoration work continues, the Fort Pitt Society is in the throes of planning the building’s anniversary celebration. Those who worked on the project also are in the celebratory spirit. Dugan, who is from Pittsburgh, was honored to be a part of a project that not only is important to his hometown, but also is a major contributor to the nation’s history. “Working to help preserve an important national landmark was very rewarding,” he says. “It’s good to know that modern technology and expert knowledge can save the 18th-century timbers for future generations. I can take my kids and show them this project.”
Visit the Fort Pitt Block House
April 1 – Oct. 31
Wednesday through Sunday, 10:30 a.m. to 4:30 p.m.
Nov. 1 – March 31
Friday through Sunday, 10:30 a.m. to 4:30 p.m.
The Block House may be closed occasionally during the restoration for the safety of its visitors. Call ahead before planning a visit.
Admission: Free, courtesy of the Fort Pitt Society of the Daughters of the American Revolution
Directions: www.fortpittblockhouse.com/directions
Phone Number: (412) 471-1764
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A comprehensive retelling of the history of the Block House has been published by The History Press Inc. Released as part of the upcoming 250th anniversary of the Block House, The Fort Pitt Block House, was written by site curator Emily M. Weaver and is available for purchase at the Block House, at local booksellers and online at historypress.net.
“The story of the Block House is not just a military history, it’s about the growth of a city and the collective power of a determined group of women who went against the standards of their times to stand up and fight for what they believed in – the preservation of the Block House,” said Weaver. “The most fascinating part of writing this book was being able read original documents – like the deed giving the Block House property and Point District land to Major Isaac Craig and his business partner Colonel Stephen Bayard in 1784 and the original letter from Franklin Nicola, offering $25,000 to the Daughters of the American Revolution for the removal of the Block House to Schenley Park (which they obviously did not accept).”
As curator of the Block House since 2011, Weaver has provided tours to tens of thousands of visitors. She is often amazed by the confusion and misunderstandings that continue to exist about the building and its history. “I am glad we now have this resource to help set the record straight,” Weaver said, “about what the Block House is, its importance to the city of Pittsburgh and early American history, and how it has managed to remain standing for the past 250 years.”