Some skilled equipment operators have a sixth sense that allows them to focus on the task at hand while maintaining awareness of the bustling, often unpredictable activity going on around them. Unfortunately, no operator has yet developed X-ray vision that allows a viewpoint through engine cowlings, cab framing and other obstructions. COURTESY of VOLVO CE The person operating this machine has a better view of objects off the ground due to obstructions. This loader model is one that researchers have used to map out machine visibility (see diagrams below). COURTESY of NIOSH Along with the ISO standard ground-level map (far
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.