World's Largest Tunnel Boring Machine Move

One of Barnhart's largest lifts ever took place in Seattle and involved the world's largest tunnel-boring machine. In early April, the $80 million machine arrived at the Port of Seattle from Osaka, Japan to help dig a tunnel beneath Seattle as part of the project to replace the Alaskan Way Viaduct. The five-story-tall machine had been taken apart into 41 pieces for transport, the largest weighing about 850 tons. The tunnel-boring machine (TBM) was met at the port by the Barnhart team. The pieces, along with hundreds of other smaller tools and equipment, were offloaded onto Goldhofer trailers in a 24-line quad-wide configuration. From there, Barnhart transported the major components to the launch pit site over nine days with teams working round-the-clock. At the site, each of the large TBM components had to be carefully staged in the correct sequence before being lowered into the launch pit for reassembly, 80 feet below the surface. Barnhart used a modular lift tower to lower the components. The feat was impressive enough to earn the praise of Juan Luis Magro, lead construction manager of Seattle Tunnel Partners, who said, "Barnhart has performed an engineering marvel."