Abstract
Improperly secured furniture, especially on the upper floors of high-rise
buildings under long-period ground motion, can prove dangerous to human
life. Fallen items of furniture such as chairs and desks could become fatal
obstacles that prevent efficient evacuation. Deformed doors could also
obstruct people from evacuating. Also, ceiling collapse damages that were
observed in large-space structures such as gymnasiums during big earthquakes
could obstruct people from using these facilities as shelters after earthquakes.
These behaviors of non-structural components in buildings have become one
of the main targets of investigation to reduce number of victims during
and after disasters.
In this research, an effective numerical code for analyzing the motion
of non-structural components such as furniture, doors and ceilings subjected
to seismic excitations was developed. The numerical code is based on the
adaptively shifted integration (ASI) – Gauss technique, which is a finite
element scheme that provides higher computational efficiency than the conventional
code. The frictional contact between objects was fully considered by employing
a sophisticated penalty method. The numerical results were validated through
a comparison with the shake-table test results of furniture, doors and
ceilings. For example, the numerical results of ceiling collapse analysis
were validated with those experimental results performed at the E-Defense
under an input of two continuous K-NET Sendai 50% waves. The acceleration
responses, the spectrum and the displacement responses obtained on the
roof matched well with the experimental result. According to the results,
the plaster boards near walls pattered down occasionally as the clips and
screws supporting the boards detached at the first peak of the first wave.
Then, the clips near roof top began to get loose due to buckling of hanging
bolts caused by vertical excitation, which ends, at the first peak of the
second wave, in drop of plaster boards in a wide range. The numerical result
had shown the collapse of the ceilings progressed owing to the detachment
of clips that connected the ceiling joists to the ceiling joist receivers.
The earthquake-resistant ceilings, on the other hand, did not detach and
fall at all as were in the experiment. The numerical code, the models of
various non-structural components and validation results are to be shown
in the presentation.