Four engineering and construction consortiums have submitted technical proposals for the new $2.16-billion Purple Line light-rail project, which will span Washington, D.C.’s northern suburbs in Maryland. The teams, which were shortlisted in January 2014 by the Maryland Transit Administration (MTA) to design, build, operate and maintain the 16-mile, 21-station system, now have until Dec. 8 to provide financial proposals for the 35-year publicprivate partnership. Cost concerns had clouded the line’s future until, in June, system modifications and increased local government contributions satisfied Gov. Larry Hogan (R) of the reduced risk to the state. Construction could begin in 2016, with full operation anticipated in 2021.
Because it can moderate the damaging effects of earthquakes, base-isolation is a technique used primarily in seismically active regions. ENR takes a look at some of the largest applications of base-isolation technologies in the world.