Courtesy FCC Total diameter of the excavated tunnels was nearly 10 meters. Related Links: Panama Canal Owner and Contractors Agree to Final Cost, Schedule Terms Excavation Under Way on Panama City Metro A design-build team led by Brazilian engineering and construction conglomerate Norberto Odebrecht and the Spanish company Fomento de Construcciones y Contratas (FCC) last month completed the 14-kilometer, $1.8-billion Panama Metro light-rail line. The work featured two earth-pressure-balanced tunnel-boring machines, each 9.77 meters in diameter, dubbed "Marta” and "Carolina." The Panama Metro route includes seven kilometers of tunnels and more than five kilometers of elevated guideway. The metro will
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.