Seismic Device Could Make Bridges and Buildings More Resilient to Earthquakes
- Tuesday, 02 April 2013
Navid Attary, a student at Rensselaer Polytechnic Institute, has created a seismic protection device to boost the resiliency of bridges and buildings to earthquakes. His innovation, which uses a new and novel method to dissipate the destructive forces of earthquakes, could help save countless lives and prevent billions of dollars of damage around the world every year.
For reducing damage, most seismic protection systems used today work by dissipating, or damping, the energy created by quakes. Passive dampers are not unlike shock absorbers in automobiles, and they usually feature a cylinder containing fluid and a piston that drives the fluid through the device. This helps redirect earthquake energy from the frame of the building or bridge to the damping device, which then harmlessly dissipates the energy in the form of heat.
While reliable and long-lived, these passive dampers have limited effectiveness because they cannot adapt to each earthquake’s unique movement patterns. Active dampers are smarter and able to respond to many different types of movement, but these electronic devices are expensive to maintain, and cease to function if power is lost during an earthquake.
Attary’s solution to this problem was to create a new type of seismic protection device that adapts to different types of movement, but requires no electricity and no expensive maintenance. He invented a rotation-based mechanical adaptive passive device, or RB-MAP, which is comprised of a meticulously engineered collection of gears, pre-torqued springs, and damping devices that can be installed underneath a bridge or inside the wall of a building. The RB-MAP takes advantage of a concept called “negative stiffness” to reduce the earthquake energy transferred into the structure. The RB-MAP can passively adapt to different types of earthquakes, as specific movements will cause selective engagement or disengagement of the gears and the damping device.
Initial testing has shown that Attary’s RB-MAP can reduce the force in structures during earthquakes by up to 60 percent. The device is inexpensive to build, and small and compact enough to be practical to install inside structures. Overall, Attary’s patent-pending technology could open the door to a new generation of seismic protection devices that help save lives and minimize destruction during earthquakes.