00539 Naoyuki Matsumoto - Timber Design Society

A STUDY ON WOODEN LATH AND PLASTER WALL
OF JAPANESE EARLY MODERN WOODEN ARCHITECTURE
Naoyuki Matsumoto 1 , Toshiaki Sato 2 and Kaori Fujita 3
ABSTRACT: This paper describes the analysis of construction elements of the shear wall of Japanese early modern
wooden architecture, the verification of seismic performance of the most common type of shear wall, and the
investigation of the building damage by the 2011 off the pacific coast of Tohoku earthquake of Former Date County
Office in Fukushima Prefecture, which is an early modern wooden architecture in Japan with most common type of
shear wall.
KEYWORDS: Early modern wooden architecture, Wooden lath, Static loading test
1 INTRODUCTION 1
During the early modern age in Japan (1853-1926, from
the end of Edo era to Taisho in this study), several ways
of constructing wooden architecture were newly
imported and invented. Since about 1960’s, those
heritages of modernization in Japan have been
researched and registered, and some studies which traced
those archives and tried to summarize them have been
conducted [ref 1, 2]. On the other hand, the verification
of seismic performance of them based on the historical
knowledge of constructional elements is not enough. So,
there still remain a lot of unknown construction methods
and their seismic performances, though there is a
increasing need of restoration of those modern wooden
architectures.
1.1 OBJECTIVE
The objective of this study is to understand the historical
and structural knowledge on the Japanese early modern
wooden architectures through tracing the historical
distribution of the construction elements of shear walls,
and investigating the structural performance of them.
1.2 METHOD
First, the typical type of shear wall in the era was
determined by analyzing the distribution of combinations
1 Naoyuki Matsumoto, Graduate Student, Dept. of Arch.,
Graduate School of Eng. , Univ. of Tokyo, 7-3-1 Hongo,
Bunkyo-Ku, Tokyo, 113-8656, Japan.
E-mail: aplus.poe@gmail.com
2 Toshiaki Sato, Postdoctoral Fellow, Dr. Eng., Faculty of
Science and Technology, Tokyo University of Science, 2641
Yamazaki, Noda-shi, Chiba, 278-8510, Japan.
E-mail: sato_t@rs.tus.ac.jp
3 Kaori Fujita, Associate Professor, Dr. Eng. , Dept. of Arch.,
Graduate School of Eng., Univ. of Tokyo, 7-3-1 Hongo,
Bunkyo-Ku, Tokyo, 113-8656, Japan.
E-mail: fujita@buildcon.arch.t.u-tokyo.ac.jp
of elements of the shear wall. For the analysis, a list
which is composed of construction elements about 61
buildings (72 cases, including duplicates) by referencing
the anamnestic studies [ref 1, 2] and the reports of
restorations of the important cultural properties was
made. Then, we analyzed the list to know the historical
distribution of the construction elements and shear wall.
Second, with the conclusion of the analysis, the
measurement of Former Date County Office in
Fukushima Prefecture, to know the details of the wall,
was performed.
Third, the static loading tests to the full-scale model
were performed to investigate the seismic performance
of that type of wall.
Fourth, building damage investigation on Former Date
County Office by the 2011 off the Pacific coast of
Tohoku Earthquake was performed, and the conditions
of the walls were compared with the result of the
experiment above.
2 CONSTRUCTION ELEMENT
ANALYSIS
2.1 The list of construction element and the analysis
Based on the anamnestic studies, we made the list of
construction elements of the shear walls of the 61 early
modern wooden architectures in Japan. 52 of them are
Important Cultural Properties, 6 are Designated Cultural
Properties, and 3 are Historic Sites.
We defined that each wall is composed of 4 planer
elements [figure 1] which enclose the frames from both
sides. These are Inner Finish(1), Inner Substrate(2),
Outer Finish(3), Outer Substrate(4). In this study, ‘Inner’
means ‘interior of the border of the plan’ and ‘Outer’
means exterior of it. The Inner Wall is composed of (1)
and (2), and the Outer Wall is composed of (3) and (4).
Figure 1 is the schematic depiction of this concept.

Figure 1: The concept of 4 constitutional elements of a wall
2.2 The Distributions of Inner Wall and Outer Wall
Then, the distributions of each element, and their
combinations on each side, and the combinations are as
follows.
2.2.1 Distribution of Each Element
On figure 2 and 3, there are the distributions of Inner
Substrate/Finish, and Outer Substrate/Finish.
0% 20% 40% 60% 80% 100%
■The types of Inner Wall
There are 8 types of Inner Walls as above. They can be
categorized 3 groups by the substrate; wooden lath,
wattle, and others.
Type (A) wall is made with wooden lath and plaster or
wallpaper. Wooden laths (about 20 to 50 mm width) are
nailed on studs and frames. On them, plaster is applied,
or wallpaper is stuck.
Type (B) wall is made with wattles and mud or plaster.
Some wattles (bamboo is the common material) are
fitted in gridline between the frames of wall and tied
with ropes. Then mud with glue is put on them more
than three times.
(A)
(B)
Figure 5:(A) wooden lath + plaster, wooden lath + wallpaper
Figure 6:(B) wattle + Plaster (mud wall), wattle + plaster
Inner
Substrate
38
21
4 3
6
Outer
Substrate
17
11
25
7
12
Figure 2: The distributions of Inner/Outer Substrate (72case)
Figure 3: The distributions of Inner/Outer Finish (72case)
From figure 2, wooden lath and wattle are common as
Inner Substrate, and wooden lath, stud and wattle are
common as Outer Substrate.
From figure 3, plaster is common as Inner Finish, and
siding and plaster are common as Outer Finish.
2.2.2 The Types and Distribution of Inner Walls
40
35
30
25
20
15
10
5
0
Inner
Finish
Outer
Finish
wooden lath wattle studs underlayer board others
0% 20% 40% 60% 80% 100%
36
62
24 34 7
424
plaster siding mortar board wallpaper others
20
5
3 4
(a) (b) (c) (d) (e) (f) (g) (h)
Figure 4: The distribution of Inner Wall (72case);
(a)wooden lath + plaster (b)wattle + plaster (c)brick + plaster
(d)underlayer board (e)studs + board (f)wooden lath + wallpaper
(g)wooden furring + plaster (h)wattle + plaster board
Then, the distribution of Inner Wall, the combinations of
Inner substrate and finish, is showed on figure 4.
From figure 4, ‘wooden lath substrate and plaster finish’
is the most common Inner Wall (36 case, 50%).
7
2 1 1
Figure 7: Others; underlayer board, studs + board, Wooden
furring + plaster, brick + plaster
2.2.3 The Types and Distribution of Outer Walls
30
25
20
15
10
5
0
25
12
7
6
4
3
2 2
1 1 1 1 1 1 1 1
(a) (b) (c) (d) (e) (f) (g) (h) (i) (j) (k) (l) (m) (n) (o) (p)
Figure 8: The distribution of Outer Wall (72case);
(a) studs + siding (b) wooden lath + plaster (c) wattle + plaster
(d) underlayer board + siding (e) wooden lath + tile + mortar
(f) tile + plaster (g) brick + mortar (h) wattle + siding
(I) wooden lath + tile (plaster in joint)
(j) under the lintel; stone, over the lintel; wattle + plaster + stone
(k) metal lath + mortar
(l) studs + drop siding (m) underlayer board + tile + plaster
(n) stone, brick, timber frame etc. (o) brick + plaster (p)brick
The distribution of Inner Wall, the combinations of
Outer substrate and finish, is showed on figure 5.
From figure 5, ‘studs and siding’ is the most common
Outer Wall.
■The types of Outer Wall
There are 16 types of Outer Walls as above. On Figure 8,
the distinctive types of Outer Walls are shown.
About type(h), which is the most common type, sidings
are only nailed on the studs or columns. Sometimes
sidings are put into the frames.
About (d) and (e), both of them using clay tiles nailed on
wooden lath, for fire prevention.

Type (g) is not so much popular those days, but after the
WWⅡ, it has been a popular way to construct the outer
wall of wooden architecture in Japan until now.
(a) (b) (c) (d)
(e) (f) (g) (h)
Figure 9: Outer Walls; (a)wattle + plaster (b)wattle + mud wall +
siding (c)wooden lath + plaster (d)wooden lath + tile + plaster
(e)wooden lath + tile (plaster in joint) (f)brick + plaster (g)metal
lath + plaster + mortar (h)studs + siding
In general, Outer Walls (16types) have more variations
than Inner Walls (8types), mainly due to the variations of
Outer Finish.
2.3 Results and Observations
On Figure 9, the combinations of Inner Walls and Outer
Walls using wooden lath as the Inner substrate are
shown. Based on the conclusion of the distributions of
Inner and Outer Walls, considering the correspondence
of Inner Wall and Outer Wall, such kind of wall as using
‘wooden lath and plaster’ as the Inner Wall , and ‘studs
and siding’ as the Outer wall is the most common
combination of shear wall in the era, and it occupied
19% (14cases) .
Among the 4 elements of this type of wall, wooden laths,
especially when they are used diagonal, mainly resist
the horizontal load.
Inner Wall (72 cases)
Outer Wall
corresponding to
'wooden lath + plaster'
Figure 11: diagonal wooden lath and siding
3 Measurement at Former Date County
Office
To investigate the shearing performance of the ‘wooden
lath and plaster’ and ‘studs and siding’ wall, we
performed the size measurement at Former Date County
Office.
3.1 Former Date County Office
Former Date County Office is located in Fukushima
Prefecture, Date County, Koori Town. It is an eclectic
wooden architecture built in 1883 by the carpenters of
the site, with two stories and a penthouse, and used as
the county office until 1926. It was also designated as
Important Cultural Properties in 1977. The dismantling
and reconstructuring are performed since 1977 to 1979.
In this building, the diagonal wooden lath, plaster, studs,
and siding are used as the shear walls, with no brace, so
it is suitable for the model of the test to investigate the
performance of the diagonal wooden lath [ref 3].
Figure 12: Former Date County Office façade and the diagonal
wooden lath interior of the wall (during the repairing)
others
22%
wattle + plaster
50%
wooden lath +
plaster
50%
27 cases: transverse
9 cases: diagonal
studs + siding
19%
others
22%
3.2 Results of Measurement
The measurement was performed on the size and interval
of nails, siding, wooden lath.
The measurement of lath was performed on the
transverse lath, as the diagonal one was not visible.
Table 1: Result of the measurement of wooden lath and siding
Figure 10: The distribution ratio of the Inner Wall and the
corresponding Outer Wall
2.4 The Diagonal Wooden Lath
Wooden lath is the thin timber board mainly used
transverse or diagonal as the substrate of a plastered wall.
Especially, the diagonal wooden lath have been said to
be similar to the brace and plywood, and have adequate
shearing capacity, but there were not so many studies
about the seismic performance of it, especially with the
specification seen in the buildings in early modern age .
So in follows, the shearing performance of the diagonal
wooden lath is tested through the static loading test.
wooden lath
siding
Sugi[Japanese ceder] 50mm wide. 12mm thick.
With diameter 6 or 8 mm nail. On 10mm from the edges.
interval 160mm. With diameter 6 or 8 mm nail.
On 20mm from the lower edge, 10mm from the upper edge.
Siding width
210mm
Overlap
20mm
Wooden
lath 60mm
Nail
Distance
17mm
50mm
17mm
Space of lath
5mm
Figure 13: The measurement of wooden lath, siding, distance of
nails

4 STATIC LOADING TEST OF THE
FULL-SCALE WALLS
By the static loading test to 4 full-scale specimen walls,
the seismic performance of the wall with diagonal
wooden lath and plaster as the inner wall, and studs and
siding as the outer wall was grasped.
4.1 Methods of the Test
All 4 specimens shear walls were tested under reversed
cyclic tests. The column base was anchored by holddowns.
A cyclic displacement was applied in-plane
along the top beam. The plus pressure [the compressive
forces works in the lath] was the right when we see the
interior side. The deformation angle was 1/600-1/15[rad].
The test ends at the 80% of the maximum strength. The
horizontal displacement and the lift up displacement are
measured by displacement meters.
4.2 The Specifications of the Specimens
4 specimens are made along with the typical
specification of the shear walls of Former Date County
Office. One side of substrate is the diagonal wooden
laths and the other is the siding. Only the specimen 4
was finished with plaster, and compared with specimen
1-3. Furthermore, on the specimen 3, all siding are
removed at 1/120 rad. The elevation of the specimen is
on the figure 10. The process of finishing with plaster is
on the figure 11.
Table 4: The notes on the specimen
specimen
1
2
3
4
Table 5: The specification of the plastered wall(specimen 4)
coating phase
raw material fresh plaster 20 1200 800 0 0
primcoating
lath coating 2 20 1200 800 0 10:1
primcoating 3 20 1200 800 0 6:4
Sageo
coating
3 20 700 700 0 6:4
middle middle
coating coating 1
6 20 700 700 0 5:5
middle
coating 2
3 20 700 700 0 5:5
finish under finish 1 20 1000 0 600 0
coating top finish 1 20 600 0 600 0
※volume ratio with each plaster
plaster
thickness
Sageo fibers for
(on lath) hydrated Tsunomata
[fibers for plastering sand※
lime [seaweed]
plastering] finish
mm kg g g g
Table 6: The specification of Sageo [fibers for plastering]
Sageo [fibers for
plastering]
specification
Diagonal wooden lath[interior], siding [exterior]
Same as 1. No planer finish on lath.
Same as 1. Siding was removed at 1/120[rad].
Same as 1. Plaster was applied on the lath.
600mm
double nail on the lath, after lath coating, and coat in
over and primcoating
nailed
4.2.1 The Specification of the specimen 4 plastering
Specimen 4 was coated with plaster. The process of
coating is as follows. At first primcoating is done on the
wooden lath, then Sageo which is twisted fiber of hemp
to prevent the falling of plaster, are nailed, and middle
coating, and finish coating is done. After the coating the
wall was dried in the air for about a week.
The material and the thickness of plaster are on table 5.
Figure 14: The elevations and the size of the specimen 1-4
Table 2: The specification of the specimen and original Former
Date County Office wall
specimen
Former
Date
County
Office
column stud beam ground sill wooden lath siding
thickness 167 167 167 167 12 18
width 185 60 180 167 60 210
length 2730 2730 2600 2600 ref figure 1820
thickness
mm
167 167(165) 167 167 12 18
width 185 60 140 167 60 210
length 9300 3000
8780(gross
1st floor)
3750 ref figure
no
description
Figure 15: The process of finishing the plaster wall
1.Primcoating 2 Nailing Sageo 3.Middle Coating 4.The
finished surface 5.The detail of Sageo
4.3 Results of the Experiment
4.3.1 The Process of Failure [specimen 1]
The cyclic loading started from 1/600[rad]. At
1/150[rad], the buckling of the wooden lath and the
drawing of nails became apparent. Then at 1/60[rad], the
same tendency kept on. At about 1/30[rad], the
maximum strength is measured and at 1/20[rad], the
nails on the column were drown out and the strength
began to decrease.
Table 3: The specification of nails and hole-down joint metal
nail
hole-down
joint metal
N75 (JIS) on siding and wooden lath. N125 (JIS) on column
upper and lower limit [at column's short tenon].
HD-20 on beams with M16 bolt(240mm),on column with M12
bolt(210mm)
Figure 16: The ultimate state of specimen 1; drawing of nails on
the lath (left),Nails drown out (right)

Initial stiffness
The result of specimen 4 (4884kN/rad) was about 2.4
times of others’ (about 2000kN/rad). So, plaster had
some correlation with the initial stiffness.
35
horizontal load(kN)
Figure 17: The details of the lath [specimen 2], the ultimate
state [specimen 2], and the flaking of the lath and plaster
[specimen 4]
4.3.2 Results and Observation
Figure 15 is the load deflection curves of 4 specimens.
The results of the maximum strength and the initial
stiffness were in follows.
25
15
5
-5
-15
-25
Specimen1
Specimen2
Specimen3 without siding
Specimen3 with siding
Specimen4
minus side
-35
-0.09 -0.07 -0.05 -0.03 -0.01 0.01 0.03 0.05 0.07
Figure 18: The load deflection curves of specimen 1-4
Table 7: Results of the test
specimen
specimen 1
specimen 2
average 1-2
specimen 3
[siding
removed]
average 3
specimen 4
average 4
pressure
direction
Deformation Angle(rad)
initial
stiffness
kN/rad
maximum
strength
kN
plus side
Wall Ratio
+ 1768 26.6 2.8
- 2080 26.7 2.6
+ 2330 27.6 2.9
- 2309 27.5 2.8
2122 27.1 2.8
+ 1123 20.5 1.6
- 1540
23.0
2.0
1331 21.8 1.8
+ 4885 26.3 3.1
- 4074 33.9 4.1
4480 30.1 3.6
■On the plus side
Maximum strength
The average of specimen 1’s and 2’s was 18kN, and
specimen 4’s was 17.5kN. Compared to them, the result
of specimen 3 was significantly smaller, 13.7kN (75% of
others). So, the effect of plaster was not observed, and
the siding had some correlation with the maximum
strength.
30
25
20
15
10
5
Horizontal Load(kN)
Deformation Angle(rad)
0
0.00 0.01 0.02 0.03 0.04 0.05 0.06 0.07
Specimen1 Specimen3 [siding removed] Specimen4
Figure 19: The load deflection curves of specimen 1-4 (plus
side)
■On the minus side
Maximum strength
The result of specimen 4 was 1.3 times of the plus side.
Others’ were almost the same.
Initial stiffness
The result of specimen 3 became 0.7 times after the
removal of siding. So, compared to it of the plus side, the
removal doesn’t reduce its initial stiffness so much.
35
30
25
20
15
10
5
Horizontal Load(kN)
Deformation Angle(rad)
0
0.00 0.01 0.02 0.03 0.04 0.05 0.06 0.07
Specimen1 (pull) Specimen3 [siding removed] (pull) Specimen4 (pull)
Figure 20: The load deflection curves of specimen 1-4 (minus
side)
■Summary
As the average, specimen 1-3, they are without plaster,
reached 27.1kN of the maximum strength at 0.03 rad of
the deformation angle. Only with this test, the correlation
of plastering and maximum strength cannot be affirmed,
but the initial stiffness became about 2.4 times. The
reason of these effects should be surveyed even at the
point of the effect of Sageo [fiber between lath and
plaster] and the jamming of plaster between the laths.
On the siding, as on specimen 3 (siding removed at
1/120[rad]) the maximum strength became about 80%, it

seems to contribute to the shearing performance by
confining the studs or so. In addition, by observing the
failure process of the specimen, we could know that
before buckling the lath, the nails are drawn and the
strength began to decrease.
4.4 Comparing with Anamnestic Research
The results of the tests were compared with one of the
anamnestic research, which specimen’s specifications
and those in our tests are alike. On table 8, the results of
the tests by Heigaku Tanabe and his colleagues [ref 4].
From Figure 18, the both sides diagonal wooden lath
wall had almost the same maximum strength (21.2kN)
with the specimen 3 (20.5kN). Judging from the spec of
that wall, it should have much more strength than that of
specimen 3. The reason of the low value is shown in his
report as the specimen of Tanabe was finally broken at
the bottom joints. So, the metal joint of the specimen did
not have enough strength.
30
25
horizontal load(kN)
20
15
10
5
both sides diagonal
timber lath
siding / transverse
timber lath
both sides transverse
timber lath
specification of walls and frames, the number of stories,
eccentricity and deterioration. In this method, the penthouse
and the addition are omitted.
In this study, two kinds of Wall Ratio, 9.80kN (the
maximum value defined in The Building Standard Law),
and 10.86kN (the result of the experiment) were used.
5.2 Observations
From the Table 9, the average of the value except 2F Beam
Direction is more than 0.8.
Except the value of 2F Beam Direction, the average of the
values is more than 0.8. On the other hand, the value of 2F
Beam Direction is 0.25 and 0.28, .
The reason why the value of 2F Beam Direction is far
smaller than others is that the wall quantity is not enough
for the big space of the assembly hall.
Compared to the building damage investigation, the small
value of 2F Beam Direction (N-S) and the heavy damage on
the North-South walls are consistent.
It is necessary for this kind of wooden architecture to
estimate precisely the weight of the building and the height
of the stories because this method is for the wooden
‘Houses’, so the result of this seismic diagnosis is only the
simple referential value. Additionally, the effects of the
penthouse and the addition have to be verified with more
precise diagnosis or other ways to know the vibration
characteristics of this building.
Deformation Angle(rad)
0
0.00 0.01 0.02 0.03 0.04 0.05 0.06 0.07
1F
Governer’s
Office
Specimen1 Specimen3 [siding removed] Specimen4
Figure 21: The load deflection curves of specimen 1-4 (plus
side) and the maximum strengths of Tanabe’s experiment.
Table 8: The specification of specimens in Tanabe’s research
researcher
Heigaku
Tanabe,
Kazuo Goto
and Chitoshi
Katsuta
publicatio
n year
specification of wall
5 Seismic Diagnosis of Former Date
County Office
The seismic diagnosis of The Former Date County Office,
which is the model of the experiment, was carried out, to
consider its seismic performance, using the wall ratio
derived from the static loading test.
5.1 Methods of Diagnosis
plaster
finish
both sides transverse
timber lath
1939
both sides diagonal timber
lath
○
siding / transverse timber
lath
maximum strength
per 1.82m
The seismic diagnosis of this study conformed to the
guideline of The Seismic Evaluation of Wooden Houses.
This method is based on Wall Amount Method. In the
method, the length of the shear walls is the index of the
seismic performance of a building, and the horizontal load
carrying capacity of different types of shear walls is
normalized to Wall Ratio.
With the Wall Ratio, we evaluate the seismic performance
of wooden houses by the ratio of Load Carrying Capacity to
Necessary Load Carrying Capacity derived from the
9.3
21.2
15.2
note
no
brace
2F
Beam
Ridge
Beam
Office
Ridge
Assembly Hall
Addition
Figure 22: 1F and 2F Plan of Former Date County Office
Table 9: The ratio of Load Carrying Capacity to Necessary Load
Carrying Capacity
Wall Ratio
(kN/m)
1F
Ridge
Direction
Beam
Direction
2F
Ridge
Direction
Beam
Direction
Standard Law(9.8) 0.91 0.77 0.72 0.25
Experiment(10.86) 1.00 0.85 0.80 0.28

6 The Building Damage Investigation on
Former Date County Office by the 2011
off the Pacific coast of Tohoku
Earthquake
On September 26 in 2011, the building damage
investigation on Former Date County Office by the 2011
off the pacific coast of Tohoku earthquake was performed.
Around the County Office, at The Town Office of Koori
Town, JMA seismic intensity lower than 6 is observed.
The County Office was damaged mainly on the walls and
the stone podium.
On the 2 nd floor, the types of damages are almost the same
with the 1 st floor. On the west side, about 30% of the wall
had fallen, and the wall beside the stairs also heavily
damaged and about 30% of them had fallen.
In addition, between the diagonal wooden laths exposed at
the stairs, there were reeds. That was the different
specification with other walls.
In the attic space of 2 nd floor, or above 3 rd floors, there were
only slight cracks.
1F
2F
Figure 25: Interior damages on the 1 st floor ;
(left) falling of plaster
(right) crack on the plastered wall
Figure 23: Heavily Damaged places of Former Date County
Office; Stone podiums at the corners. Plastered wall on the West
side, Plastered Wall beside the stairs
6.1 Exterior Damages
The corners of stone podium are broken and moved
(maximum 50mm). The stone pavement on the main
entrance also displaced. The column in front of the entrance
cracked and displaced.
Figure 26: Interior damages on the wall beside the stairs; falling
of plaster
Figure 24: Exterior damages ;
(left) displacement of corner of the stone podium
(right) displacement and crack of entrance column and
pavement
6.2 Interior Damages
On the 1 st floor, there were cracks on and fallings of the
plastered walls and the glass in the doors. On the ceiling
[wallpaper], there also were some tears.
In the addition which is constructed in the traditional way
unlike the main building, the edge of the mud walls fell and
cracked, but compared with the main house, less damaged.
Figure 27: Interior damages on the 2 nd floor; falling of plaster on
the west side, partition wall, peeling of paper on the ceiling,
falling of plaster from above window( the directions of cracks
runs at right angles to the diagonal wooden lath)

6.3 Summary of the damage investigation
1. On the most interior walls, there are cracks and falling,
especially on the west side walls on the 2 nd floor, and the
wall beside the stairs. On the other hand, in both big rooms
on 1 st and 2 nd floor [Office, Assembly Hall], the walls are
less fallen. Many cracks start from the corner of the window
and run along the diagonal lath.
2. In the previous experiment on specimen 4, at 1/450[rad]
the first crack ran, at 1/150[rad] the left edge of the wall
began to fall, at 1/60[rad] the left side plaster almost fallen
and at 1/75[rad] the right side of the plaster also fallen. It
reached to the maximum strength at 1/30[rad].
Compared with specimen 4 in the ultimate condition and
the exposed wall in the County Office, it seems that the
amount of settled plaster between the laths is different. That
is, in the County Office, the bonding of plaster and the
wooden lath was weaker than that of specimen 4. In
addition, in the experiment on specimen 4, the drawing and
compressive strain were observed and the bonding by Sageo
lasted, but on the wall in the County Office, there seemed to
be less of them. So, the stiffness of the walls might have
decreased earlier than in the experiment. That is, it is
important to confirm the specification of metal joint at the
bottom and the nails to know how that kind of destructive
action happened.
Figure 28: The ultimate condition of specimen 4 and west side
wall in Former Date County Office
Figure 29: The details of wooden lath;
(left) exposed wooden lath in the wall beside the stairs
(right) wooden lath in the Specimen 4. Sageo still remains.
3. The bias of the damaged area should be verified by the
seismic diagnosis or the microtremor measurement to know
the torsion of the building, especially at the joint part with
the addition. The joint part is just the wall beside the stairs
which is heavily damaged.
4. The penthouse is said to have experienced large
vibrations, but the damage on the wall was slight. Though it
can be assumed that is because the penthouse was relatively
light, it also should be verified by the microtremor
measurement.
5. The falling and displacement of the stone podium also
observed in other early modern wooden architectures in
Fukushima Prefecture. For example, Former Fukushima
Junior High School which construction element of the wall
is similar to that of Former Date County Office was
damaged on the stone podium and emergency repaired with
steel pipes.
7 CONCLUSIONS
First, by the analysis of the distribution of construction
elements and their combinations of 61 early modern
wooden architectures in Japan, it is revealed that the
most common type of shear wall consists of wooden lath
as Inner Substrate, plaster as Inner Finish, studs as Outer
Substrate and siding as Outer Finish. It occupies 19% of
the candidates.
Second, by the static loading test, it is confirmed that the
most common wall has much more seismic resistance
than that is prescribed in the existing Building Standards
Act in Japan (about 4.8 times as Wall Ratio).
Finally, by the damage investigation of Former Date
County Office by the Pacific coast of Tohoku
Earthquake, some characteristics of the damage of
wooden lath wall was determined.
In the next step of the study, on the historical analysis of
construction elements used in early modern Japan,
expanding the list of the objective architectures and
analysing more precise correlation of the elements of
construciton with each other are important.
On the verifycation of seismic performance, the seismic
effects of the plaster, together with Sageo and siding
need to be investigated.
ACKNOWLEDGEMENT
This study has been done through the courtesy of Juichi
Kanno, the manager of Former Date County Office. We
deeply thank him for his kindness.
REFERENCES
[1] Chie Sakuma and Shinichiro Matsudome, “A Study
on Wall Structure’s Change of Western Style
Wooden Housing Built during the Age of
Introduction of Western Technology in Japan,”
Polytechnic University of Japan, Master Thesis,
2004.
[2] Aihiko Minamoto, The History of the Modernization
of Wooden Frame Work Method in Japan, Chuo
Koron Bijutsu Publishing, 2009.
[3] The Japanese Association for Conservation of
Architectural Monuments, “The Report of the repair
for conservation of Former Date County Office,”
1979.
[4] Heigaku Tanabe, Kazuo Goto, Morio Kikuta, “The
Lateral Cyclic Loading Test on Timber Frame with
Shear Wall: The Study on the Earthquake and Wind
Resisting Timber Structure part 7,” Architectural
Institute of Japan Annual Convention, 1939