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Compare and contrast these two things:

In this video about the new Oakland Bay Bridge:

http://baybridgeinfo.org/media/video/inside-bay-bridge#.T0ExRBzU-_E

the presenter, Bart Ney, says

"...this is going to be a gem that will live for 150 years"

"...all of this rebar you see coming up through this wood falsework is for the column that sits underneath the structure, it's basically what supports all of this"

"...there's a tremendous amount of steel in our concrete bridges here in California"


Now in this:

http://www.npr.org/2012/02/17/147047553/concretes-role-as-a-building-block-in-history

NPR Science Friday interview Robert Courland, historian and author of "Concrete Planet: The Strange and Fascinating Story of the World's Most Common Manmade Material", says this:

"the steel that's in reinforced concrete, which gives it its tensile strength, also dooms the material to a very short lifespan. Steel-reinforced structures, particularly those exposed to the elements, like I say, for instance, a freeway bridge are - will eventually corrode. The rebar will eventually rust, and as it rusts, its diameter expands by something like four or five fold. And then it destroys the concrete around it while it is being destroyed by the rust. And so that's why concrete structures only last between, say, 50 and 125 years because of rebar corrosion"

"so we really need to stop building with steel reinforced concrete, because we just have to demolish and rebuild the structure every 75 - 100 years"

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