State transportation officials are avoiding weeks or even months of wait time in inspecting underwater bridge components by using the latest in sonar imaging technology. The method’s potential will become the focus of a federal study next year. Photo: Randalls Photography Advanced technology helped inspectors get images of underwater bridge piers and footings when diving was too dangerous. This spring’s record floods posed high risks for the 80-year-old Sorlie Bridge, which connects Grand Forks, N.D., and East Grand Forks, Minn. Flowing 30 ft higher than normal, the fast-moving Red River of the North engulfed the 605-ft-long, two-span truss structure’s timber
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.