Highway in the Sky: Building bridges with welding

摘要

Bridges are a hot topic when American infrastructure is discussed. A 2005 "report card" issued by the American Society of Civil Engineers reported that, the percentage of the nation's 590,750 bridges rated structurally deficient or functionally obsolete decreased slightly from 28.5 percent to 27.1 percent between 2000 and 200.3. That report noted that it would cost USD9.4 billion a year for 20 years to eliminate all of the deficiencies on bridges across the U.S., and said that term underinvestment is compounded for the long term by the lack of a federal transportation program. There are two new bridges, however, that will open to traffic within the next 8 months.