U.S. Department of Transportation
Federal Highway Administration
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Washington, DC 20590
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Conditions and Performance
Status
of the Nation's Highways, Bridges, and Transit:
2002 Conditions and Performance Report
|
Exhibit 11-31:
Year of Construction and Cumulative ADT - Prestressed Concrete Superstructure Bridges
Exhibit 11-31 is a bar graph that shows the construction of prestressed concrete superstructure bridges. The vertical axis measures number of bridges from 0 to 18,000 in increments of 2,000 bridges. The horizontal axis has 21 bars, one for each 5-year period between 1900 and 2000. New prestressed concrete superstructure bridges were less than 1,000 for each period to 1955, then rose sharply to 5,500 by 1960 and more than 12,000 by 1970. The bars then rise more slowly to 14,000 in 1981-85, 16,000 by 1990, and then drops to 13,000 in 2000. There are also two lines and a second vertical axis (measuring percentages from 0 to 100 in increments of 10 percent) in this chart. The first, representing cumulative percent of structure population, rises slowly from 0 to 10 percent by 1960, the rises steeply to 40 percent by 1975, 75 by 1990, and 100 by 2000. The other line, representing cumulative percentage of ADT, parallels the first line, and at 1960 stays at 1 to 10 percentage points higher.
Source: National Bridge Inventory.
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Page last modified on November 7, 2014
