Science-fiction writers have spun countless tales of malevolent, rampaging robots laying waste to helpless cities as panicked citizens flee in horror. Now, life is imitating this pulpy art—at least to some extent—with the emergence of a more benign but immensely versatile type of remote-controlled robot designed specifically for demolition work. Fitted with hydraulic breakers and other attachments, track-based, electrically powered demolition robots can venture into interiors, hazardous environments and confined spaces to dismantle floors, ceilings and wall slabs, keeping workers out of the way of falling concrete and other dangers. Demolition robots, which are free from the emissions issues associated
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.