Aviad Shapira, civil engineering professor, textbook author and former project engineer for his family’s concrete construction business, is not afraid to climb hundreds of feet up a rickety ladder to get a bird’s-eye view of the world. “I climb tower cranes whenever I get the chance,” he says. “Too many of us researchers are detached from the subject.” Photo: Aviad Shapira Shapira is helping builders plan for tower-crane risks. The high-level view has afforded Shapira a unique perspective. The teacher at The Technion-Israel Institute of Tech- nology, Haifa, says many crane accidents can be attributed to what he calls a
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.