Related Links: Steel Pipe Found Stuck in Bertha's Cutterhead When North America's largest tunnel-boring machine pushed a 50-ft-long, 8-in.-dia steel pipe seven feet out of the ground on Dec. 3, joint-venture contractor Seattle Tunnel Partners and Washington State Dept. of Transportation officials didn't think much of it."Bertha," the 57.5-ft-dia machine, kept churning its state Route 99 tunnel path below Seattle at faster-than-predicted paces. But only for three more days.Now, that pipe—a well casing put in place in 2002 to measure groundwater movement following the 2001 Nisqually earthquake, the very same earthquake that serves as the catalyst for Bertha boring a
The market is generally healthy and steadily growing, and margins are up for large specialty contractors. Further, advances in design tools and owner demand for collaboration are giving subcontractors a seat at the table early on in projects.