Related Links: Mayor McGinn Finally Gives In A $2-billion deep-bore tunnel along Seattle’s downtown waterfront appears to have overcome what may be its final obstacle to construction, garnering the approval of nearly 60% of voters in a referendum on whether the city should give the notice to proceed with the project.The tunnel, scheduled for completion in 2015, is the centerpiece of a $3.1-billion Washington State Dept. of Transportation program to replace the seismically suspect double-decked Alaskan Way Viaduct. That thoroughfare carries approximately 110,000 vehicles each day along one of Seattle’s primary north-south arteries. Damage from the 2001 Nisqually Earthquake sparked
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.