Seattle’s South Spokane Street Viaduct is one step closer to reality with the recent selection of PCL Construction Services Inc., Bellevue, Wash., for the final $60.3-million phase of a four-year widening program. The 60-year-old elevated roadway is the main east-west connector between Interstate 5 and West Seattle. Plans call for widening the two-lane, 3,000-ft-long structure to 86 ft—nearly double its current width—and adding new ramps and collector lanes. South Spokane Street, which runs beneath the viaduct, will be reconstructed to include new curbs, sidewalks and improved pedestrian and bicycle access. The entire project is scheduled to be substantially complete in
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.