Tuesday, November 24, 2009
Innovative structure sensors
According to Globe Update, the restored St. Anthony Falls Bridge, on I35W across the Mississippi River, contains 323 sensors to monitor for structural weaknesses, strained joints and corroded concrete and reinforcing. The previous bridge collapse on August 1, 2007.
According to Catherine French, a structural engineering professor at the University of Minnesota, who heads a project to collect and interpret data from the new bridge, sensors suggest issues requiring investigation and possible repairs. Also, the St. Anthony Falls Bridge is made of high performance concrete containing coal-combustion byproducts fly ash and silica fume, making it denser and more waterproof. A different approach, with the same results, has been elaborated at the University of Michigan in Ann Arbor, whereby a mixture of carbon nanotubes and polymer that is very strong and has electrical properties allowing it to act as a sensor skin.
This great new technology will apply not only to bridges, but dams and high-rise buildings exposed to high velocity winds. We see an application in South Florida construction, where high-rises and hurricanes inhabit the same landscape.