Boston Valley Terra Cotta restored the Alberta Legislature Building's century-old dome using a combination of digital and traditional techniques.Restoring a century-old terra cotta dome without blueprints would be a painstaking process in any conditions. Add long snowy winters and an aggressive freeze/thaw cycle, and things start to get really interesting. For their reconstruction of the Alberta Legislature Building dome, the craftsmen at Boston Valley Terra Cotta had a lot to think about, from developing a formula for a clay that would stand up to Edmonton’s swings in temperatures, to organizing just-in-time delivery of 18,841 components. Their answer? Technology. Thanks to an ongoing partnership with Omar Khan at the University at Buffalo’s School of Architecture and Planning, the Orchard Park, New York, firm’s employees are as comfortable with computers as they are with hand tools. On site in Edmonton, technicians took a 3D laser scan of the dome prior to disassembly. They also tagged specific terra cotta pieces to send to New York as samples. These pieces, which ranged from simple blocks to gargoyles and capitals, went straight to the in-house lab for scanning into Rhino. The drafting department combined the overall scan with the individual scans to create a total picture of the dome’s surface geometry and depth. The individual scans, in addition, were critical to making the approximately 508 unique molds employed on the project. To compensate for the eight percent shrinkage clay goes through during drying and firing, the craftsmen at Boston Valley used to have to perform a series of calculations before building a mold. “[Now we] take the scan data and increase by eight percent by simply doing a mouse click,” said Boston Valley national sales manager Bill Pottle. In some cases, the craftsmen converted the scan data into a tool path for the five-axis CNC machine used to make the molds. “We’re doing that more and more in some of our mold making. It also allows us to ensure that we’re recreating them to the most exacting tolerance and dimensions that we can,” said Pottle. The data from the 3D scans also helped the craftsmen replicate the dome’s complicated curvature. “Between the scanned pieces and the scan of the dome itself, we were able to figure out some very complex geometry where each of these individual pieces had the correct shape to them,” said Pottle. For sustainability and durability, the designers at Boston Valley reconfigured the dome as a rain screen system, with terra cotta components attached to a stainless steel frame. But while the rain screen boosts environmental performance, it also demands incredible precision. Again, the 3D models proved invaluable. “The models allowed these tight tolerances. [We] could explode it and make sure everything was connected. It would have been impossible without that level of sophisticated software,” said president John Krouse. The Alberta Legislature Building dome restoration is the first major project on which Boston Valley has unleashed its full array of digital design tools. Krouse hopes its success—he estimates that the digital tools speeded fabrication by 200 percent—will send a message to designers interested in experimenting with terra cotta: “What we’re trying to say to the architecture and design community globally is don’t be afraid to start designing domes with complex geometry, because we’re equipped with all this technology. It doesn’t have to be a square box.”
Posts tagged with "Edmonton":
At the beginning of the 19th century, the city of Edmonton was considered one of Canada’s most important rail hubs. For over two decades the trains that once made Edmonton a prominent center of economic activity have ceased to run along those tracks, and the historic freight yard has remained vacant. Over the years a prominent old overpass connecting 97th Street to Edmonton’s downtown rail yards has morphed into a poorly finished, unattractive concrete pedestrian walkway and bicycle path. This weekend designers Chelsea Boos, Carmen Douville, and Erin Ross, will begin working on a project to revitalize the historic landmark. According to the Edmonton Journal the artists, with the help of a group of volunteers, will bring the bridge back to life by planting 25 circular raised beds filled with vibrant flowers, indigenous plants, and edible crops from which visitors can actually pick fruit from. The trio aims to transform the old bridge into an open public garden that will continue to attract cyclists and pedestrians as well as provide local residence with a green outdoor space to relax while enjoying views of downtown and Chinatown. The project, which is undeniably resonant of New York City’s High Line, aims to bring community members together through the creation of a mural painting and future events that will be hosted on the site. Despite the rough neighborhood surrounding the bridge, the designers, who are passionate about urban projects dedicated to improving city life, insist on leaving the park open to the public in the hopes that visitors will be respectful of the property and even be inclined to help maintain it.