Page 119 - Abstract book - TJSSF-2020

Thailand – Japan Student Science Fair 2020 (TJ-SSF 2020)
“Seeding Innovations through Fostering Thailand – Japan Youth Friendship”

Designing a stronger and simpler traditional Japanese “Kigumi”

Asumi Fujita , Ayano Suzuki , Jou Ogihara , Rinta Sasaki
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Advisor: Miki Misumi
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Sapporo Kaisei Secondary School
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Abstract

We are investigating about “Kigumi,” which is one of the techniques of Japanese traditional
architecture. Kigumi has been used in pillars and beams of the structures of Japanese traditional houses,
shrines and temples. It is made by making some incisions in wood and fitting them without nails or
screws, so the pillars or beams would be able to absorb the shock of earthquakes by some tiny spaces
between the wood. However, this method is becoming obsolete because there are modern, easier, and
cheaper methods of joining woods with nails or screws. Many buildings that don’t use Kigumi have
suffered damage from earthquakes, causing fatalities. If Kigumi is implemented more easily and at
lower price, we could decrease the number of fatalities of house collapses. Therefore, we propose a
method to develop a modern style Kigumi which is stronger and simpler than traditional Kigumi. As a
basic experiment, we crafted models of three different types of existing Kigumi named Koshikake,
Hozo, and Kama by craft papers, and shook them to simulate earthquakes to verify what kind of shapes
of incisions can keep standing with its original Designing a stronger and simpler traditional Japanese
“Kigumi” structure, even if earthquakes occur. We discovered that Kama was the strongest of the three
against shaking. It kept its own structure for more than a minute, even in a shaking equivalent to
magnitude 5 earthquake. After we analyzed the results of the first basic experiments, we designed brand
new and simple incisions of Kigumi. Then, we are now making models of them by using the 3D printer.
We are planning to design another Kigumi and do the second experiments to verify the strength of our
new Kigumi.

Keywords: Kigumi (Japanese traditional building technique), earthquake, architecture, wood working,
structure, sympathetic vibration

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