A Finite Element Approach to Analyze Motion Behaviors of Indoor Non-Structural Components of Buildings
Abstract
The Great East-Japan Earthquake, which occurred on March 11th, 2011, had
caused catastrophic disasters along the coast side of East-Japan mainly
by a huge tsunami driven by the diastrophism. The earthquake not only damaged
structural components of buildings and facilities but also indoor non-structural
components of buildings which were located several hundred kilometers away
from the epicenter. Indoor non-structural components such as ceilings,
doors and furniture, could become fatal obstacles that obstruct people
from evacuating or could even injure them. Motion behaviors of these indoor
non-structural components have become one of the main targets of recent
investigations to reduce number of victims in such events. Under these circumstances, a finite element code, which can handle
motion behaviors of non-structural components of buildings, was developed.
The code was developed with a use of an ASI (Adaptively Shifted Integration)-Gauss
technique which was originally developed to simulate collapse behaviors
of buildings. It provides higher computational efficiency than the conventional
code in those problems with strong nonlinearities including phenomena such
as member fracture and elemental contact. @One of the applications of the numerical code was a ceiling collapse analysis
of a gymnasium under seismic excitation. It is very important, nowadays,
to know the collapse mechanism of the ceilings since it causes not only
the possibility of human injuries, but may disturb the use of the facilities
after earthquakes. The behaviors of plaster boards near walls and roof
top, which drop occasionally due to detachment of clips and screws, were
well simulated. The behaviors of door frames in a ten-story reinforced
concrete (RC) building during seismic excitations were also simulated.
According to the simulation, the door frame in lower level had deformed
to a critical angle that could likely damage the door and make it difficult
for people to evacuate, while the story-drift angle of the building itself
had not reached to a critical one. Another application of the numerical
code was a motion analysis of furniture under seismic excitation. A sophisticated
penalty method was applied, in this case, to realize the slip and contact
motions of furniture with and without casters. The tumbling motions of
furniture were well simulated as a whole in spite of different conditions
of seismic waves.
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