SEATTLE – By combining memory-retaining metal rods and a bendable concrete composite, a new State Route 99 exit ramp taking shape in Seattle will become the first bridge in the world built to sway with a strong earthquake and return to its original shape.
This pilot project is the first real-world test of 15 years of research inside the Earthquake Engineering Lab at the University of Nevada, Reno – one of the top earthquake engineering laboratories in the U.S.
Modern bridges are designed not to collapse during an earthquake, but this new technology takes that design a step further. In earthquake lab tests, bridge columns built using memory-retaining nickel/titanium rods and a bendable concrete composite proved more flexible. The columns were able to return to their original shape after an earthquake as strong as a magnitude 7.5;
“This is potentially a giant leap forward,” said Tom Baker, bridge and structures engineer for the Washington State Department of Transportation. “We design for no-collapse, but in the future, we could be designing for no-damage and be able to keep bridges open to emergency vehicles, commerce and the public after a strong quake.”