Anearly 7,000-ft-long railroad bridge is undergoing an extreme $35-million makeover over the Hudson River, thanks to hundreds of precast concrete panels, community zeal and the windblown determination of engineers and contractors. When completed by October, the revamped 121-year-old Poughkeepsie-Highland Railroad Bridge may be the world’s longest pedestrian bridge at 6,768 ft, say officials. Photo: Bergmann Associates Old railroad bridge will become a soaring walkway over the Hudson River when it opens later this year. Photo: Bergmann Associates Work in high winds over the river was a challenge. The historic bridge’s 3,094-ft-long, 25-ft-wide main span consists of seven trusses supported on
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.