Despite billions of dollars in federal, state and local funds directed toward the maintenance of existing bridges, 69,223 bridges — 11.5 percent of total highway bridges in the U.S. — are classified as “structurally deficient,” requiring significant maintenance, rehabilitation or replacement.
Two key problems persist: while Congress has repeatedly declared bridge safety a national priority, existing federal programs don’t ensure that aging bridges actually get fixed; and the current level of investment is nowhere near what is needed to keep up with our rapidly growing backlog of aging bridges.
We have a local bridge that the link claims carries 7,200+ cars a day. I would have thought less, but I’ll buy that number. The bridge is on a Federal Highway so it also carries a lot of heavy truck traffic.
The bridge borders a municipal park and has a walkway beneath it. This makes inspection quite easy. The bridge deserves it’s “D” rating. The concrete has spalled exposing much of the rebar reinforcements. The rebar has totally rusted away in parts.
Four things contribute to degeneration of our highways and bridges. The first is truck traffic. They have a habit of breaking the base which in turn cause the sub-surface and surface also to crack. Car traffic has very little damaging effect on bridges or roads.
The second is the freeze and thaw cycle. Water that seeps into the cracks from both beneath and the top freezes, opening up the cracks even more. This with heavy truck traffic will accelerate the degeneration of the roadway.
Third is the use of salt on the roads to melt snow. This accelerates corrosion in bridges That corrosion also expands the concrete and causes spalling and degeneration of the concrete. This may be reduced by using zinc anodes.
The fourth is the natural subsidence that occurs from having a weight on the ground and erosion. Roads in swampy or wet sand areas often have this problem as well as bridge piers that don’t reach the bedrock.
There is a rather simple public choice explaination for why things are built and seldom maintained: elected officials are eager to show their constitutents that they have provided some new service to their districts which they can finance through debt(prefereably with their names stamped on the project), so they will seek to have new infrastructure project created; and yet when it comes to providing continued maintenance, well let’s just say that “Sen. Smith’s new layer of asphalt on I-95” isn’t as sexy as the “Sen. Smith Memorial Bridge.”
Here is a speech by a well-known liberal on why the government doesn’t have any money for vital repairs.
http://tinyurl.com/3goru95
The average republican explanation.
http://tinyurl.com/3eyphg6
#38, Damn. It took you 20 minutes to respond. You’re getting slow in your old age 🙂
#39, Oh, and I agree with you, too!