A New Orleans contractor tried and failed four times to drive sheet piles through a dense soil layer with progressively larger vibratory hammers and an impact hammer. The fifth attempt is succeeding, thanks to the right tool: a hydraulic press that slides the steel in with great force, rather than banging it down. + Image Photo: Giken Seisakusho Co., Ltd, Tokyo Workers use hydraulic-reaction press to drive steel sheet piles into difficult ground. Related Links: Sheet Driver Tackles Tough Project In late 2005, as part of emergency repairs after Hurricane Katrina, the U.S. Army Corps of Engineers let a contract
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.