A 125-ft-tall boom lift tipped over in downtown Philadelphia on Oct. 12, killing the operator who was harnessed in the bucket. The worker, James Wilson of Glassboro, N.J., was inspecting exterior masonry of a church, according to Philadelphia Fire Dept. Commissioner Lloyd Ayers. Wilson may have driven the lift over a “manhole or grate” in the sidewalk that collapsed under the weight of the machine, Ayers said. The lift struck a neighboring five-story apartment building, sending debris to the street and injuring three bystanders. Ayers said the area is normally “bustling” with pedestrians, but the accident occurred during the Columbus
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.