Detailed text transcripts for TV channel - MSNBC - 20150522:09:07:00
Are built to last about 50 years, but the average age is 24 years so you can see why so many of them are in bad need of repair. >> the holes in the end of the beam. >> reporter: virginia bridge engineer shows us what happens when 45,000 cars a day drive over a bridge for 30 years. >> water and salt water pass through that joint on a regular basis and that causes the corrosion of the steel beam. >> reporter: the federal highway administration considers one out of every nine bridges in the u.s. structurally deficient meaning it needs significant repairs, maintenance or replacement like this one....
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