What's the Latest Development?
Civil engineer M. Saiid Saiidi and his team at the University of Nevada-Reno have created a composite material that they claim can make bridges stronger and more durable than traditional steel and concrete. The main ingredient is nickel titanium, which is used in eyeglass frames because of its flexibility. The team combined it with both concrete and engineered cementitious composites (ECC), and compared those mixes with steel and concrete in an earthquake simulation program and a shake table. The nickel titanium/ECC mix "outperformed the traditional steel and concrete...on all levels."
What's the Big Idea?
Many bridges around the world are made of steel and concrete, a mix that doesn't always hold up well in the event of a strong (7.0 magnitude or greater) earthquake. Nickel titanium is one of several shape metal alloys that can withstand heavy strain and return to its original state. It also has the added advantage of being 10 to 30 times more elastic than steel. Bridges that use a nickel titanium/ECC composite would be slightly more expensive to build but less expensive to repair, and they would still be usable after a moderate to severe earthquake.
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