Civil Engineering Reference
In-Depth Information
Table 2.2. Which metro areas have the most bridges? Ranked by bridges
per 100,000 population, 2010
# per 100,000 Pop.
Total bridges
1
St. Louis, MO-IL
163
4583
2
Pittsburgh, PA
158
3724
3
Cincinnati-Middletown, OH-KY-IN
146
3123
4
Dallas-Fort Worth-Arlington, TX
139
8888
5
Houston-Sugar Land-Baytown, TX
103
6145
Source:
National Bridge Inventory
IS INFRASTRUCTURE AGING?
It requires little argument to win assent to the idea that the nation's infra-
structure is aging, since everything is aging, including your present authors.
For bridges, the pertinent question is whether they are on the average getting
older—whether at some time the United States reduced its construction of
new or replacement bridges, allowing older bridges to increase as a propor-
tion of all bridges. If so, we have to be concerned about our aging bridges.
We tapped into the NBI to find out. Our findings tell a story that's
more complicated than we expected. The number of bridges built shot up in
the 1960s and has declined since then (figure 2.1). The declining number of
120000
104383
100000
80027 80406 79930
74787
80000
58965
60000
48232
40000
30133
26290
20000
9048
9217
0
Source: National Bridge Inventory
Figure 2.1. US Bridges in 2010 by Decade of Completion.
