COMPDYN 2019

Numerical Studies on Seismic Motion Behaviors of Non-Structural Components
in Buildings
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2

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Daigoro Isobe , Koichi Kobayashi , Kazuki Sato , Kotoku Maeda , Hiroyuki Omura
1University of Tsukuba
1-1-1 Tennodai, Tsukuba-shi, Ibaraki 305-8573, Japan
isobe@kz.tsukuba.ac.jp
2

Graduate school, University of Tsukuba
1-1-1 Tennodai, Tsukuba-shi, Ibaraki 305-8573, Japan(s1720934, s1720937, s1720973, s1820884)@s.tsukuba.ac.jp
ABSTRACT
Improperly secured furniture, especially on the upper floors of high-rise buildings under long-period groundmotion, 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 fromevacuating. 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. Thesebehaviors of non-structural components in buildings have become one of the main targets of investigation toreduce 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 [1], which is a finite element scheme thatprovides higher computational efficiency than the conventional code. The frictional contact between objects
was fully considered by employing a sophisticated penalty method [2]. The numerical results were validated
through a comparison with the shake-table test results of furniture, doors and ceilings. For example, thenumerical results of ceiling collapse analysis were validated with those experimental results performed at theE-Defense under an input of two continuous K-NET Sendai 50% waves. The acceleration responses, thespectrum 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 getloose due to buckling of hanging bolts caused by vertical excitation, which ends, at the first peak of thesecond wave, in drop of plaster boards in a wide range. The numerical result had shown the collapse of theceilings 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 theexperiment. The numerical code, the models of various non-structural components and validation results areto be shown in the presentation.
References[1] D. Isobe, Progressive Collapse Analysis of Structures: Numerical Codes and Applications, Elsevier, eBook
ISBN: 9780128130421, Paperback ISBN: 9780128129753, 2017.
[2] D. Isobe, T. Yamashita, H. Tagawa, M. Kaneko, T. Takahashi and S. Motoyui, Motion Analysis ofFurniture under Seismic Excitation using the Finite Element Method. Japan Architectural Review.
2018;00:1-12. https://doi.org/10.1002/2475-8876.1015.

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