Experiment of
HUGE Japanese Traditional Wooden Frame
(under Construction)

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Joint Research
of
Japanese Association for Conservation of Architectural Monuments
and
Laboratory of Engineered Timber Joint,
Wood Technology Div., Timber Engineering Sec., FFPRI

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AIMS

Since ancient days in JAPAN, the wooden buildings of temple and/or shrine have heavy column and structural system named masu-gumi in its Axial members. These system are not well studied than Truss system and/or rigid frame. But in fact, These Wooden buildings are last under natural disaster in long period.

In this experiment, HUGE specimen is modeled from structural part of Japanese traditional wooden frame. And its dimension is full-size to actual structure. we want to make these following things clear. Which is...

the restoring force for stabilizing frame made by column rocking under seismic horizontal loading
the effect of masu-gumi, and continuous bloster to structural stiffness
the efficiency of reinforcement steel plate applied to joint
etc.

The structural performance of Japanese traditional frame work was studied by Sizuo BAN as the name of "Structural study on Wooden frames of Shrine and/or Temple" in 1941 before World War II. In its report, the relationship between horizontal resisting force and deflection is explicable with column rocking in traditional Japanese frame work under vertical loading.
Before Nara Period (AD 710), The major part of structural resisting force was the restoring force under seismic load and/or wind load, we think. So we must study this restoring force on traditional Japanese frame work before to verify its seismic load and/or wind load safety. This is the best way to study with full-size specimen loading.

We can summarize this experiment as following substances...

full-size specimen: modeled from actual structure
vertical loaded: same amount of upper structure and live load
horizontal loading: controlled by deflection (displacement at the top of specimen)
measuring: how strong the restoring force is
We will be able to verify the Japanese traditional frame work.

The real structure is consisted with bloster and bearing block(mentioned before as masu_gumi) except column and kashira_nuki girder. To make sure to know the whole structural performance, we had another experiment about masu_gumi system besides the axial frame experiment. So this study about "Japanese Traditional Wooden Frame" has two different experiment.

experiment about masu_gumi system: behavior and resisting force of masu_gumi
experiment of full-size space frame: behavior and characteristics of axial members and lower part of masu_gumi

experiment of full-size space frame

This experiment aims to know the behavior and characteristics of axial members and lower part of masu_gumi system. And also aims to know that, how the restoring force works for stabilizing frame under seismic horizontal loading.
The specimen was modeled from the structure of grand floor in 2 story Japanese traditional frame work. The position of this specimen is outer part of floor plan. The horizontal loading direction is parallel to girder. The specimen is a space frame structure which has 1 story and 1 span for each direction. The girder span is 5022mm, and beam span is 4431mm. Specimen is consisted by number of parts listed below from the lowest one, and without any bonding.

fundation stone with dowel in its center
HUGE column(diameter 709mm, length 5317mm) placed on stone
kashira-nuki girder placed into column groove
large bearing block set upon it by using dowel
crossed 2 way bloster placed into its groove
half span post set with mortise and tenon joint
bearing blocks placed on by using dowel
continuous bloster placed into groove of bearing blocks

The masu_gumi system was singled to fit to actual condition of horizontal loading to column. All materials are domestic "Japanese cypress" grown in yoshino region.

The specimen is vertical loaded by using oil jack, pulling down the loading frame placed on continuous bloster at the point of column center. And also the horizontal loading frame (which surrounds continuous bloster and jointed to the end of it) is loaded by using 2 oil jack linked to reaction wall.

Specimen: Plan(Japanese), Elevation(Japanese).
Loading frame: Plan(Japanese), Elevation(Japanese)。
View from A Point 1(Japanese), View from A Point 2(Japanese).
Photo Album(Japanese).

experiment about masu_gumi system

This experiment aims to know the behavior and resisting force of masu_gumi system. The specimen is modeled from actual structure upon column in ground story as full-size one. And it is consisted with number of parts listed below from the lowest one ...

large bearing block named "daito" mounted on floor with steel box
bloster named "hijiki" placed into its groove
2 way bearing block named "houto" placed on cross point of "hijiki" with dowel pin
1 way bearing block named "makito" placed on the each end of "hijiki" with dowel pin and also on half span post
continuous bloster named "toushi hijiki" place into the groove of "houto" and "makito"
half span post named "ken to tsuka" set with mortise and tenon joint on lower continuous bloster

The dimensions are following. full length: 7972mm, width: 2360mm, height: 2006mm, span: 5022mm(center to center of large bearing block). The dimensions and units are as same as experiment of full-size space frame.
All materials are domestic "Japanese cypress" grown in yoshino region except large bearing block which is hemlock.

Specimen: Plan(Japanese), Elevation(Japanese).
Loading frame: Plan(Japanese), Elevation(Japanese).
Photos: Specimen Assembly(Japanese), Loading frames Assembly(Japanese), Snaps in Specimen Assembly(Japanese).
View from A point: Specimen Assembly(Japanese), Loading frames Assembly(Japanese).
Photo Album(Japanese)

Reference

Shizuo BAN: Structural study on Wooden frames of Shrine and/or Temple Part 1 restoring force for stabilizing made by column rocking, Technical report for Annual assembly, 1941/04, pp.252-258, Architectural Institute of Japan (Japanese)

Open Laboratory was happened

Date : 1997/03/10(Mon.),11(Tue.)
Where : "The 2nd testing building of wooden structure" in FFPRI
Time schedule was following...(Same in both day)
13:30PM Start / Introduction / Horizontal loading / Observation / End 15:00PM