New product announcements: 04/28/2010 Vibrating Concrete Screed: Single Operator Required The E-Screed is a battery-powered, vibrating screed that requires only one operator for strike-off of wet concrete. The screed’s high-frequency vibration produces uniform vibration distribution over the entire blade length, enhancing the integrity of the concrete. The screed is powered by a 36-V lithium-iron-phosphate battery that boasts over 1,500 lifetime cycles. The E-Screed battery-powered unit can be used with existing Magic Screed blades. Allen Engineering Corp.; 870-236-7751; www.alleneng.com Compact Excavator: Redesigned Boom The redesigned Bobcat 324 compact excavator features a boom cylinder attached to the top—instead of the bottom—of the
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.