jUNE 17, 1999
A new building technique could prevent much earthquake damage in the
future.
The National Science Foundation says special shock absorbers filled with a
new kind of fluid will soon prevent buildings from falling apart in
earthquakes.
Science Specialist Ed Yeates shows us how.
Scientists at Notre Dame believe they've found a way to stop violent
shaking in buildings which tears them apart in earthquakes.
It all stems from a remarkable fluid which solidifies when hit with
strong ground motion.
A magnetic field, produced by the earthquake, apparently triggers that
change from liquid to solid.
"Low viscosity fluid much like water-- whenever it's not experiencing a
magnetic field. Whenever placed in a magnetic field, it turns into a solid."
Norte Dame engineers have now placed the fluid inside specially designed
shock absorbers, and placed
them strategically in test buildings.
The shocks remain fluid when there's no earthquake, giving a building
flexibility to gently sway in wind.
Billie Spencer Jr., of the University of Notre Dame explains, "The shock
absorbers are typically placed in diagonal braces in the walls. They could be
installed in a new installation or it could be installed in a retrofit
application."
On a shaker table, a simulated earthquake violently shakes a three story
frame. The water on top clearly demonstrates the power of the ground motion.
But with shocks installed, the magnetic field created by the quake
solidifies the fluid inside the shocks. They stiffen, dampening the energy,
making the building more rigid - more strong - and less likely to fall apart.
The shocks could be used on almost all buildings - on bridges - even heavy
equipment where vibration is not only annoying, but destructive.
The N.S.F. says the new shock absorbers could be commercially available to
builders within three to five years.
