1

Structural Health Monitoring of Structural Health Monitoring of Huge Traditional Timber Structure Huge Traditional Timber Structure

in Japanin Japan

Kyoto Univ. (Japan)Kyoto Univ. (Japan) Yasuhiro HAYASHIYasuhiro HAYASHIGoei-do

Wooden Framed Structure of Wooden Framed Structure of GoeiGoei--dodo

http://www.tomo-net.or.jp/

2

Typical Beams of Typical Beams of GoeiGoei--dodo

http://www.tomo-net.or.jp/

http://www.tomo-net.or.jp/

3

Kyoto-net K-NETKyoto-net（Wood houses）

Seismic Seismic Observation Observation Network Network in Kyotoin Kyoto

(Kyoto(Kyoto--net)net)Hongan-ji

Kyoto

Goei-do Mon(12)

Goei-do(27)Amida-do(12)

Free field(6)

Observed StructuresObserved Structures（（No. of comp.No. of comp.））

4

Arrangement of SeismometersArrangement of Seismometers

NS69.7m

37.4m

Gojyu

Sanjyu

Ushibiki

Ashigatame

Kidan

59.1mWE

NS WENS WE

(b) Amida-do (c) Goei-do Mon

(a) Goei-do

・Strong motion・Ambient Vibration

（once a week）

SeismometersSeismometers

5

Fundamental Vibration Mode of Fundamental Vibration Mode of GoeiGoei--dodo

f=0.8Hz (Long. direction)f=0.8Hz (Trans. direction)

0.7

0.8

0.9Goei-do (Long.) Goei-do (Trans.)

03/11 04/1 04/3 04/5 04/7 04/9 04/11 05/1

Freq

uenc

y (H

z)

DATE

0.9

1

1.1

1.2Amida-do (Long.) Amida-do (Trans.)

03/11 04/1 04/3 04/5 04/7 04/9 04/11 05/1

Freq

uenc

y (H

z)

DATE

0.91

1.1

1.21.3

1.4Goei-do Mon (Long.) Goei-do Mon (Trans.)

03/11 04/1 04/3 04/5 04/7 04/9 04/11 05/1

Freq

uenc

y (H

z)

DATE

Seasonal Variation in Natural FrequencySeasonal Variation in Natural Frequency2003.112003.11--2004.122004.12

30

50

70

90Original data

03/11 04/1 04/3 04/5 04/7 04/9 04/11 05/1

Ave

rage

rela

tive

hum

idity

(o)

DATE

Smoothed data

0

20

40Original data

03/11 04/1 04/3 04/5 04/7 04/9 04/11 05/1Ave

rage

tem

pera

ture

(o)

DATE

Smoothed data

0

2

4

6 Original data

03/11 04/1 04/3 04/5 04/7 04/9 04/11 05/1

Ave

rage

win

d ve

loci

ty (m

/s)

DATE

Smoothed data

Temperature

Humidity

Wind velocity

Goei-do

Amida-do

Goei-do Mon

6

Observed Earthquake RecordsObserved Earthquake Records

No.5No.16

No.27

No.10

No.9

No.2

No.8

No.17No.18

No.20No.19

No.21

No.25

No.1

No.22-24

No.3,4No.6,7,11-15

Higashi Honganji templeEpicenter Mjma

(a) Hypocenters (b) Frequency of PGVs

0

5

10

15

0 5 10 15 20 25 30Fr

eque

ncy

PGV (mm/s)

Honganji The Tokai-do EQ.

-30

0

30

0 50 100 150 200 250 300Time (s)

Vel

ocity

(m

m/s

)

Ground velocity （Long. direction）

The TokaiThe Tokai--do earthquakedo earthquake（（2004/09/062004/09/06））

-3

0

3

0 50 100 150 200 250 300Time (s)

Rel

. dis

p. (

mm

)

Long. (NS)

Relative displacement

7

Fourier spectral ratio of Fourier spectral ratio of GoeiGoei--dodo

0

20

40

0 1 2 3

Long.Trans.

Spec

tral

rat

io

Frequency (Hz)

Goei-doPGV=0.7mm/s

22mm/s

The Tokai-do EQ.

Variation of natural frequency Variation of natural frequency during observed earthquakesduring observed earthquakes

0.5

0.6

0.7

0.8

0.9

0.001 0.01 0.1 1 10

Long.Trans.

Peak

freq

uenc

y (H

z)

Max relative displacement (mm)

8

(a) Natural frequency

(b) Relative displacement

Temporal Variation of Temporal Variation of natural frequency and vibration modenatural frequency and vibration mode

0.5

0.6

0.7

0.8

0 50 100 150 200 250 300

Translational Torsional

Time (s)N

atur

al f

req.

(H

z)

a

bc

d ef

gh

0

1

2

0 50 100 150 200 250 300

Translational Torsional

Time (s)

Rel

. dis

p. (m

m)

ab c d e f g h

ConclusionsConclusions

• The natural frequencies of the three timber structures are identified to be ranging from 0.8 to 1.3 Hz from ambient vibration measurements.

• The seasonal variation in the natural frequency average due to humidity is about 5% of the annual average.

• Natural frequency decreases drastically as the deformation increases but recovers to the original value as the deformation decreases.

• When considering the seismic safety of the Goei-do, torsionalresponse should be considered. Because torsional response will be dominant as the total response increases.