Krøll is known for making the heftiest tower cranes in the world, but its rigs are rarely seen in the wild. A contractor is using one to help build out a tunnel that will house new light-rail lines in downtown Seattle.As a portion of a larger $1.8-billion U-Link project that adds 3.15 miles of light-rail track in twin-bored tunnels from downtown Seattle north to the University of Washington, JCM—a joint venture of Jay Dee, Frank Coluccio and Michels Pipeline—had to stage its tunneling work on the same site as the program's Capitol Hill Station project. That job takes up about
Arch dams, classically curved monoliths situated in narrow valleys, are not as common as other types of dams, such as embankment dams and gravity dams. ENR takes a look at some of the biggest arch dams in the world, both completed and under construction.