25-08-2017, 09:32 PM
ADVANCED TECHNOLOGIES IN HOUSING CONSTRUCTION
ADVANCED TECHNOLOGIES IN HOUSING CONSTRUCTION.pdf (Size: 568.47 KB / Downloads: 316)
SEISMIC ISOLATION
Seismic isolation is a relatively new concept in earthquake engineering, having been
introduced in the early 1980s in the USA and New Zealand, and as early as 1975 in the
former Soviet Union. Quite simply, the idea underlying the technology is to detach the
building from the ground in such a way that the earthquake motions are not transmitted
up through the building, or are at least greatly reduced.
PASSIVE ENERGY DISSIPATION DEVICES
Passive energy dissipation systems represent an alternative to seismic isolation as a
means of protecting building structures against the effects of damaging earthquakes.
The basic function of passive energy dissipation devices in a building is to absorb or
consume a portion of the earthquake input energy, thereby reducing energy dissipation
demand on primary structural members and minimizing structural damage. The means
by which the energy is dissipated is either through the yielding of mild steel, sliding
friction, motion of a piston or a plate within a viscous fluid, motion of an orificed viscous
fluid device, or viscoelastic action of polymeric materials. The most common types of
passive devices used-to-date include viscous fluid dampers, friction dampers, metallic
dampers, and tuned mass dampers. These devices can be effective against wind
motions as well as against earthquakes4.
EARTHQUAKE PERFORMANCE
Typically, all the buildings built with these new technologies have performed or are
expected to perform well in major earthquakes. In fact, unlike some of the other
construction technologies described in the WHE, this technology is used to improve
a building’s performance in an earthquake. In China, where the use of base isolation
for rigid masonry buildings is becoming more widespread, these buildings have been
subjected to numerous strong earthquakes and have all performed well. No damage
to this building type has been observed in any of these earthquakes: 1994 Taiwan Straits
(M 7.3); 1995 Yunan Province (M 6.5); 1996 Yunan Province (M 7.0), and the 2000 Xinjian
Autonomous Region (M 6.2).