General Motors has launched its 2011 Chevrolet Silverado HD and GMC Sierra HD with aims of winning the heavy-duty power battle. ENR accepted GM’s invitation to test and compare its re-engineered trucks against the competition, namely the 2011 Ford Super Duty that we reviewed in the spring. Nuts and Bolts GM has beefed up the two available powertrains in its 2011 offerings to handle heavier loads. Starting things off is the 6.0-liter V-8, good for 360 horsepower and 380 lb-ft of torque. Impressive, but GM’s Duramax turbodiesel—a 6.6-liter V-8— delivers 397 horsepower and 765 lb-ft of torque, and packs 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.