Photo Courtesy of Caterpillar Inc. Tier-4 regulations are driving some alternative-power options such as the Caterpillar 336E-H, a hybrid excavator that promises to consume 25% less fuel than its nonhybrid sibling. Related Links: Are Clean-Diesel Engine Rules Stifling Innovation? Medium-Duty Truck Owners Struggle With Downtime If you think that the latest round of off-road clean-diesel mandates, or Tier 4, will kill off the engine that powers the majority of construction equipment, think again. A new guard of sophisticated, clean-burning, electronic engines are rendering extinct the prehistoric, smoke-belching, mechanical diesels of yesteryear. Cleaner power costs more up front, but it promises
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.