Building damage by the 2011 off the Pacific coast of Tohoku earthquake and coping activities by
NILIM and BRI collaborated with the administrationby
Isao Nishiyama1, Izuru Okawa2, Hiroshi Fukuyama3 and Yasuo Okuda3
ABSTRACT

structural steel buildings and reinforced concretebuildings is presented with typical damage
patterns observed also from the Quick Report.
The database on the damaged buildings subject
to tsunami which is compiled in the Quick
Report is utilized to verify the tsunami load
defined in the Guidelines [1.3] for tsunami
evacuation building made by the Cabinet Office.

This paper presents the outlines of the strong
motions observed mainly by the Building
Research Institute (BRI) Strong Motion Network,
the motion induced building damage and thetsunami induced building damage by the 2011
off the Pacific coast of Tohoku earthquake (theGreat East Japan earthquake) (hereinafterreferred to as the Tohoku earthquake). Coping
activities in order to establish necessary technicalstandards by the National Institute for Land &Infrastructure Management (NILIM) and BRI
collaborated with the administration are also
outlined.

In consideration of the building damage and soon by the Tohoku earthquake, “tsunami”, “nonstructural elements”, “long-period earthquake
ground motion” and “liquefaction” are important
technical issues to be countermeasured by theadministration. On these issues, the generaloutline of the coping activities by NILIM andBRI collaborated with the administration
utilizing the Grant-in-aid [1.4] for maintenanceand promotion of building codes / standards is
introduced.

As for the strong motions, it presents observed
motions at in and out of the buildings to show theearthquake input and the response of thebuildings. It also presents observations of thesuper high-rise buildings and the seismicallyisolated buildings under long-period earthquake
ground motions. Ministry of Land, Infrastructure
Transport and Tourism (MLIT) and NILIM withthe assistance of BRI released the Tentative New
Proposal [1.1] for countermeasure against longperiod earthquake ground motion on super highrise buildings and seismically isolated buildings,
whose general outline is also introduced.

KEYWORDS: Building Damage, Falling Down
of Ceilings, Liquefaction, Long-Period Ground
Motion, Tsunami, 2011 off the Pacific Coast of
Tohoku Earthquake

As for the motion induced building damage, it
presents the general outline of the field survey onwood houses, structural steel buildings,
reinforced concrete buildings, seismicallyisolated buildings and so on with the classified
typical damage patterns for each structural
systems based on the Quick Report [1.2], which
does not give complete survey because of thewidely damaged area affected by the Tohoku
earthquake.

1 Director, Building Department, National Institute forLand & Infrastructure Management (NILIM), Ministry ofLand, Infrastructure, Transport & Tourism (MLIT),
Tsukuba-shi, Ibaraki-ken 305-0802, Japan.
2 Senior Research Fellow, Department of StructuralEngineering, Building Research Institute (BRI), ditto.
3 Chief Research Engineer, Department of StructuralEngineering, BRI, ditto.

As for the tsunami induced damage of buildings,
the general outline of damage of wood houses,

11. INTRODUCTION

Ibaraki and Chiba Prefectures and Urayasu City
on the Tokyo Bay, damage of residential land
associated with liquefaction was surveyed.

The Tohoku earthquake of moment magnitude(Mw) 9.0 occurred at 14:46 JST on March 11,2011 and generated gigantic tsunami in the
Tohoku and Kanto Areas of the northeastern partof Japan. This was a thrust earthquake occurringat the boundary between the North American andPacific plates. This earthquake is the greatest inJapanese recorded history and the fourth largest
in the world since 1900 according to U.S.
Geological Survey [1.5]. An earthquake of Mw
7.5 foreshock preceded the main shock on March
9 and many large aftershocks followed including
three Mw 7-class aftershocks on the same day ofthe main shock.
As the epicentral distribution of the aftershocksof the Tohoku earthquake (hypocentral region) is
widely located off the coast of the prefectures of
Iwate, Miyagi, Fukushima and Ibaraki withapproximately 450km in length in North-South
direction and 150km in width in East-Westdirection. The distance from these prefectures tothe fault plane is almost the same, thus the places
with the seismic intensity of about 6 (6+ or 6-)
according to the Japan Meteorological Agency(JMA) widely spread in these prefectures. The
maximum JMA seismic intensity of 7 wasrecorded by the strong motion recording network(K-NET) [1.6] of the National Research Institutefor Earth Science and Disaster Prevention(NIED) at Kurihara City (K-NET Tsukidate)shown by the purple color in Fig. 1.1, Miyagi
Prefecture, where the instrumental seismic
intensity was 6.6.

Fig. 1.1 JMA Seismic Intensity Map

Tono City

Miyako City
Yamada Town

Kitakami City

Otsuchi Town
Kamaishi City

Hiraizumi Town

Ohunato City
Kurihara City

Rikuzentakata City
Kesennuma City
Minamisanriku Town
Ishinomaki City
Onagawa Town
Higashimatsushima City
Matsushima Town
Shiogama City
Shichigahama Town
Tagajo City
Sendai City

Field survey by NILIM and BRI was started
from Kurihara City and was followed by thelocations shown in Fig. 1.2. In this paper, theresults of the field survey at these locations arereported. In the coastal area from Aomori
Prefecture to Miyagi Prefecture, the tsunami
induced building damage was mainly surveyed.
The area facing to the Pacific Ocean in
Fukushima Prefecture was excluded from thesurvey in the cause of the accident in Fukushima
Daiichi Nuclear Power Station. At the catchment
basin area of Tone River in the border between

Nasu Town
Yaita City
Shirosato Town
Kasama City
Chikusei City
Shimotsuma City
Koga City
Bando City
Joso City
Tsuchiura City
Ryugasaki City
Sakae Town
Urayasu City

Natori City
Iwanuma City
Watari Town
Yamamoto Town
Shiroishi Town
Fukushima City
Nihonmatsu City
Miharu Town
Koriyama City
Sukagawa City
Shirakawa City
Hitachiota City
Hitachi City
Naka City
Hitachinaka City
Mito City
Oarai Town
Omitama City
Hokota City
Kashima City
Itako City
Kamisu City
Inashiki City

Surveyed Cities and
Towns

Fig. 1.2 Locations of Surveyed Cities and Towns

2

These surveys were made from the viewpoint offinding whether there is something to reflect tocurrent building structural codes or not. Namely,
are there new damage pattern in the motion
induced building damage? In case for tsunami
induced building damage, the technicalinformation on the collapsed, overturned, washedaway buildings are collected to verify the load
effect by tsunami. As will be explained in thefollowing chapters, the motion induced building
damage is generally small and especially thosebuildings which satisfy current seismic code after
1981 performed quite well with almost no severe

damage such as collapse reported.
Strong motions are recorded in good quality
during many large scale aftershocks in addition
to main shock and foreshock at in and out of thebuildings by the BRI Strong Motion Networkand so on. Especially, they are valuable to see thecharacteristic of long-period earthquake groundmotion, which is thought to be strongly
generated and amplified in the occasion of huge
earthquake, and to see the corresponding
building responses.

60,000People injured

50,000People missing
People death

40,00030,00020,00010,0000
3/12 3/19 3/26 4/2

4/9 4/16 4/23 4/30 5/7 5/14 5/21 5/28 6/4 6/11 6/18 6/25 7/2

Kobe EQ

7/9 7/16 7/23

(a) People death, missing and injured
500,000
450,000
Half collapsed (house)

400,000

Total collapsed include washed away (house)

350,000
300,000
250,000
200,000
150,000
100,000
50,0000

3/12 3/19 3/26 4/2 4/9 4/16 4/23 4/30 5/7 5/14 5/21 5/28 6/4 6/11 6/18 6/25 7/2 7/9 7/16 7/23

Kobe EQ(housing
units)(b) Total collapse and half collapse of houses

Fig. 1.3 Progress of People Death (top) and Building Collapse (bottom) by the Tohoku Earthquake
compared with those by Kobe Earthquake

The statistical data on the people death and thebuilding collapse are announced from the
National Policy Agency [1.7] (August 15, 2011).
Fig. 1.3(a) shows the progress of people death
which is compared to that in the 1995 Hyogoken
Nambu earthquake (Kobe earthquake), whichshows that the number of people death in the
Tohoku earthquake is almost 2.5 times as that in
the Kobe earthquake. Fig. 1.3(b) shows the
progress of building collapse which is again
compared to that in Kobe earthquake. The unit of
the statistical data is different, “house” for the

Tohokuearthquake
and“housing
units=household” for the Kobe earthquake, but it
can be said that “total collapse” and “halfcollapse” are both almost half in the Tohoku
earthquake. The Tohoku earthquake is muchlarger than the Kobe earthquake and the affectedarea is far larger as a result, and also the washedaway houses are included in the total collapsedbuildings. Thus, the motion induced building
damage is far below in damage ratio than that in
the Kobe earthquake. The Press Release [1.8] by
the Urban Bureau of MLIT showed that the total

3

collapsed houses in the tsunami inundation area
reached about 120,000, which is almost the same
number of total collapse by the National Policy
Agency. This fact agrees well with the result by
the field survey.

structuralelementssuch
asceiling,
countermeasure for long-period earthquake
ground motion on super high-rise buildings etc.,
and countermeasure for liquefaction ofresidential land. NILIM and BRI arecooperatively working on coping activities
collaborated with the administration, which isalso introduced in this paper.

As the lessons from the Tohoku earthquake, thefollowing administrative issues are listed up:
load effect on building by tsunami,countermeasure for falling down of non-

2. EARTHQUAKE AND GROUND MOTIONS
44˚

2.1 Earthquake Mechanism

43˚
42˚

The Tohoku earthquake occurred with wide
seismic source extending from off Sanriku to thecoast of Ibaraki Prefecture as shown in Fig. 2.1[2.1]. The figure also shows the slip distribution
on the fault place estimated using the strong
motion records from the near recording stations
shown with green triangles. The green star showsthe epicenter, the rupture initiation location forthe main shock.

41˚

IJMA
7
6
5
4
3
2
1

40˚
39˚
38˚
37˚

Main shock
2011/03/11 14:46(h=24km, Mw9.0)

36˚
km

35˚
0

100

200

34˚
134˚ 135˚ 136˚ 137˚ 138˚ 139˚ 140˚ 141˚ 142˚ 143˚ 144˚ 145˚ 146˚

Fig.2.2 JMA Seismic Intensity Distribution for theMain Shock

It was also clarified that the Tohoku earthquake
occurred on the subduction zone between the
Pacific and the North American plates and wasof thrust type. The Tohoku earthquake generated
large tsunami and the devastation caused theunprecedented enormous loss of lives andsubstantial damage to the broader society in theeastern Japan.
The magnitude of the event was determined Mw
9.0 by JMA, the largest in the earthquake
instrumentation history of Japan.
2.2 Distribution of Seismic Intensities
Fig.2.1 Slip Distribution on Earthquake Source
analyzed using Near Site Strong Motion Records(Yoshida et al., 2011 [2.1])

Fig. 2.2 shows the distribution of JMA seismic
intensities observed during the main shock. An

4asterisk( ★ ) represents the location of theepicenter. The seismic intensity 7 was observedin Kurihara City, Miyagi Prefecture, and JMA
seismic intensity 6+ was observed in wide areaof Miyagi, Fukushima, Ibaraki, and Tochigi
Prefectures. The area with JMA seismic intensity
6- extends to Iwate, Gunma, Saitama, and Chiba
Prefectures.

Tsukidate station that recorded JMA seismic
intensity 7, and K-NET Sendai and K-NET
Hitachi stations among seismic intensity 6+
stations.
Among strong motion recording stations, only KNET Tsukidate, which is located in Kurihara City,
Miyagi Prefecture, recorded the seismic intensity
7 during the main shock of the Tohoku
earthquake. From the acceleration records in theupper-row in Fig. 2.3, a maximum accelerationin the N-S direction is understood to havereached almost 3700 cm/s2, representing that themain shock caused excessively severe
earthquake motions. As seen from the pseudo
velocity responses on the right diagram, a
response in the N-S direction with a period of
about 0.2 seconds becomes particularly large.
This indicates earthquake ground motions thatare dominated by short periods.

2.3 Characteristics of Earthquake Motions
During the Tohoku earthquake, severe groundmotions were observed in wide area, and massive
amounts of strong motion records wereaccumulated. This section describes thecharacteristics of strong motion records atrecording stations that suffered high seismic
intensities, based on K-NET of NIED [1.6]. Fig.
2.3 shows acceleration waveforms and pseudo
velocity response spectra with the damping ratio
of 5% of strong motion records at K-NET

143˚

142˚

141˚

40˚

(cm/s2)

-3000
3000

E-W (peak:- 1285 cm/s2)

0(cm/s2)

-3000
3000

39˚

K-NET Tsu kid ate (7)U-D (peak: 1886 cm/s2)

2
40

60

80

(cm/s2)

100
120Time (sec)

140(cm/s2)E-W (peak: 987 cm/s2)

0(cm/s2)

U-D (peak:- 299 cm/s2)(cm/s2)

50

60

80

100
120
Time (sec)

100

35 ˚

140

140˚

141˚

142˚

143˚

(cm/s2)139˚

180

E-W (peak:- 1187 cm/s2)

0

U-D (peak: 1159 cm/s2)

IBR003: K-NET Hitachi

80

100
120
Time (sec)

140

160

180

200

1

0.5
1
Period (sec)510

Pseudo Vel. Resp. Spectrum (h=5%)
0
00
10

00
10
0
10
10
0

100
50

s)
/s/
m
(c
10 10

10

2
60

)

N-S

0.1 E-W
(cU-D
m
)

500

5

40

/s /s
m
(c
10 10

0.1

0

20

0
10
10
0

10

-3000
0

10

50

200

0

-3000
3000

138˚

160

N-S (peak:- 1599 cm/s2)

-3000
3000
(cm/s2)

0

40

5

00
10

100

2

3000

km

0
00
10

5

20

1

0.5
1
Period (sec)

500 Pseudo Vel. Resp. Spectrum (h=5%)0

MYG013: K-NET Sendai
Acceleration

N-S

0.1 E-W
(c
U-D
m
)

0.1

-3000
0

36˚

200

0

-3000
3000

K-NET Hitach i (6+ )180

N-S (peak: 1520 cm/s2)

-3000
3000

37˚

160

s)
/s/
m
(c
10 10

10
5

20

0
10
10
0

50

0

MYG004: K-NET Tsukidate
3000 Acceleration

K-NET Sen d ai (6+ )

00
10

100

-3000
0

38˚

0
00
10

Pseudo Velocity Response (cm/s)

140˚

Pseudo Velocity Response (cm/s)

139˚

500 Pseudo Vel. Resp. Spectrum (h=5%)N-S (peak: 2679 cm/s2)

0

Pseudo Velocity Response (cm/s)

138˚(cm/s2)3000 Acceleration

N-S

0.1 E-W
(cU-D
m
)

0.1

1

0.5
1
Period (sec)510

Fig.2.3 Acceleration Waveforms and Pseudo Velocity Response Spectra recorded at K-NET Stations

K-NET Sendai, which is located about 4 km east
from the Sendai Station, recorded Intensity 6+
during the main shock. A maximum accelerationin strong motion records (mid-row in Fig. 2.3)
obtained from the network exceeds 1500 cm/s2 in
the N-S direction, indicating a higher level of the5main shock. In contrast to K-NET Tsukidate,earthquake motions that were recorded in K-NET
Sendai are dominated by a period range of 0.5 toabout 1 second, and a maximum response
velocity exceeds 200 cm/s. This result is
considered to reflect ground conditions in thearea of K-NET Sendai that is covered with athick alluvium.

about 20 seconds and 70 seconds on the timeaxis, but the strong motion record obtained atmuch southern station such as K-NET Hitachi,
Ibaraki Prefecture in Kanto Area shows one large
wave group. This phenomenon may haveoccurred associated with the focal rupture
process and the wave propagation to recording
stations.

The lower-row in Fig. 2.3 shows strong motion
records that were obtained from K-NET Hitachi
in Hitachi City, Ibaraki Prefecture. A seismic
intensity of the main shock that was measured inthis network represented seismic intensity 6+. A
maximum acceleration in the N-S direction
reached a higher level, or about 1600 cm/s2,
while the pseudo velocity response spectra had apeak at about 0.3 seconds. On the other hand, theresponse was sharply reduced at a period longer
than 0.5 seconds. This indicates that theearthquake motions were dominated in shortperiod range. Both records of K-NET Tsukidate
and K-NET Sendai show two wave groups at

2.4 Results of BRI Strong Motion Network
The BRI conducts strong motion observation thatcovers buildings in major cities across Japan[2.2]. When the Tohoku earthquake occurred, 58
strong motion instruments placed in Hokkaido to
Kansai Areas started up. Peak accelerations of
the strong motion records are listed in Table 2.1.
Locations of the strong motion stations areplotted in Fig. 2.4 and Fig. 2.5. Among them,
about 30 buildings suffered a shaking withseismic intensity 5- or more. This section
presents some characteristic strong motion
records.

6

Table 2.1

Strong motion records obtained by BRI strong motion network (1/4)

3.4

B2F*
15F
01F*
192°
09F
01F
167° 07F
GL*
B1F*
180°
09F
01F*
182°
04F
GL*
G30
G105
164°
10F
01F
B1F
B1F*
164°
06F
08F
087°
B1F*
A01*
A89
BFE
180°
8FE
MBC
M8C
180° 01F*
B1F*
004° 01F
06F
B1F*
061°
07F
195° 01F*

Max. Acc. (cm/s2)
H1
H2
V
163
259
147
361
346
543
333
330
257
908
728
640
138
122
277
246
197
359
174
174
240
175
176
147
579
449
260
34
36
14
37
39
15
286
210
61
86
89
49
36
46
32
120
123
206
91
122
73
100
104
58
97
110
55
348
335
78
175
192
44
50
47
24
279
227
248
142
153
102
194
191
136
597
506
344
203
206
152
682
585
311
281
273
165
327
233
122
92
76
198
126
91
243
28
40
14
39
55
14
28
25
15

357

5.1

000° 01F*

269

263

151

Yachiyo City Hall

361

5.3

NIT

Nippon Institute of Technology

362

5.1

MST

Misato City Hall

367

4.9

B1F
302° GL*
07F
GL*
288° 01F
06F
01F
258° GL*
07F

140
312
486
230
150
283
72
130
219

135
306
359
197
119
322
104
127
190

92
171
145
79
63
131
71
73
106

Code

Station nameΔ (km)IJMA

Azimuth074°

SND

Sendai Government Office
Bldg. #2

175

5.2

THU

Tohoku University

177

5.6

MYK

Miyako City Hall

188

4.8

IWK

Iwaki City Hall

210

5.3

TRO

Tsuruoka Government Office
Bldg.

275

3.9

HCN2

Annex, Hachinohe City Hall

292

5.2

HCN

Main bldg., Hachinohe City
Hall

292

4.6

AKT

Akita Prefectural Office

299

4.3

ANX

Building Research Institute

330

5.3

BRI

Training Lab., BRI

330

5.4

TKC

Tsukuba City Hall (Baseisolation)

334

5.2

NIG

Niigata City Hall

335

3.9

HRH

Hirosaki Legal Affairs Office
Noda Campus, Tokyo Univ. Of
Science

346

YCY

TUS

Loc.

Note) Δ: epicentral distance, IJMA : JMA instrumental seismic intensity (using an asterisked sensor), Azimuth: clockwise direction
from North, H1, H2, V : maximum accelerations in horizontal #1 (Azimuth), horizontal #2 (Azimuth+90°) and verticaldirections

7

Table 2.1

Strong motion records obtained by BRI strong motion network (2/4)

CodeStation nameΔ (km)IJMA

FNB

Educational Center, Funabashi
City

368

4.7

CHB

Chiba Government Office Bldg.
#2

369

4.9

ICK

Gyotoku Library, Ichikawa City

375

5.2

EDG

Edogawa Ward Office

377

4.8

ADC

Adachi Government Office
Bldg.

377

4.8

SIT2

Saitama Shintoshin Government
Office Building #2

378

4.4

SITA

Arena, Saitama Shintoshin
Government Office Building

378

4.5

TDS

Toda City Hall

380

5.0

AKB

Akabane Hall, Kita Ward

380

4.6

SMD

Sumida Ward Office

380

4.3

NMW

National Museum of Western
Art (Base-isolation)

382

4.8

UTK

Bldg. #11, University of Tokyo

383

4.7

TKD

Kosha Tower Tsukuda

385

4.4

CGC

Central Government Office
Bldg. #6

386

4.4

CG2

Central Government Office
Bldg. #2

386

4.2

CG3

Central Government Office
Bldg. #3 (Base-isolation)

386

4.5

AzimuthLoc.

01F
357° GL*
08F
B1F
346° 08F
GL*
01F*
321° 02F
05F
01F*
003°
05F
01F*
012°
04F
B3F*
340° 10FS
27FS

Max. Acc. (cm/s2)
H1
H2
V
144
147
63
133
145
105
359
339
141
152
122
51
375
283
117
168
175
100
164
163
71
178
186
80
240
300
104
112
112
69
256
299
77
118
103
71
266
146
95
74
63
42
119
138
62
248
503
107

313° 01F*

90

105

47

GL*
354° B1F
08F
B1F*
354°
06F
20F
000° 08F
B1F*
GL*
B1FW
218°
01FW
04F
7FN
7FS
348°
01F
GL*
01F*
180° 18F
37F
01F*
208° 20B
19C
B4F*
208° 13F
21F
B2F*
208° B1F
12F

203
140
425
85
180
385
263
69
265
100
76
100
181
201
73
197
87
118
162
90
208
179
75
137
121
104
55
94

206
173
531
139
250
290
197
66
194
79
89
77
212
360
151
218
98
141
198
86
148
133
71
113
131
91
41
82

53
65
160
59
86
81
46
34
150
84
87
90
58
160
49
79
41
64
108
45
173
130
49
72
104
58
62
104

Note) Δ: epicentral distance, IJMA : JMA instrumental seismic intensity (using an asterisked sensor), Azimuth: clockwise direction
from North, H1, H2, V : maximum accelerations in horizontal #1 (Azimuth), horizontal #2 (Azimuth+90°) and verticaldirections

8

Table 2.1
CodeStrong motion records obtained by BRI strong motion network (3/4)
Station nameΔ (km)IJMA

NDLA Annex, National Diet Library

387

4.5

NDLG Ground, National Diet Library

387

5.0

387

4.5

390

4.8

NDLM
NKN

Main Bldg., National Diet
Library
Nakano Branch, Tokyo Legal
Affairs Bureau

Azimuth

Loc.

B8F
B4F
354°
01F*
04F
G35
354° G24
GL*
01S*
354°
17S
06F
359°
01F*
01F
000° GL*
07F
03F
090° 01F
GL*
01F*
045° 02F
07F
B1F*
157°
11F

Max. Acc. (cm/s2)
H1
H2
V
61
88
53
68
101
56
76
104
84
125
192
94
72
71
51
95
116
54
224
201
93
70
94
60
458
489
111
172
375
56
126
158
54
174
169
60
181
189
71
316
223
66
129
329
55
110
136
53
167
143
50
107
77
30
133
123
49
366
304
76
8
7
8
35
27
9

TUF

Tokyo University of Marine
Science and Technology

390

5.0

KDI

College of Land, Infrastructure
and Transport

401

4.6

KWS

Kawasaki-minami Office,Labour Standards Bureau

401

4.7

NGN

Nagano Prefectural Office

444

2.7

447

3.5

180° GL*

25

28

13

466

2.7

468

3.9

140° 01F*
B1F
GL*
006°
01F
08F

17
47
51
37
41

20
39
44
52
51

8
18
20
20
25

517

2.9

225° GL*

12

19

10

520

4.2

165°

01F*
11F
B1F*
292°
6F
GL*
G10
G34
167°
B1F
01F
09F
172° GL*
GL*
174° B2F
12F
07F
216°
01F*

28
81
9
32
12
10
5
8
10
16
10
8
9
25
16
6

40
56
10
31
14
10
5
12
16
19
9
15
14
46
8
5

15
18
8
10
6
4
3
4
6
12
5
7
7
4
3

HKD
HRO
YMN

SMS
SMZ

Hakodate Development andConstruction Department
Hiroo Town Office
Yamanashi Prefectural Office(Base-isolation
Shimoda Office, Shizuoka
Prefecture
Shimizu Government Office
Bldg.

KSO

Kiso Office, Nagano Prefecture

524

2.6

KGC

Kushiro Government Office
Bldg. (Base-isolation)

558

2.6

HKU

Hokkaido University

567

2.7

NGY

Nagoya Government Office
Bldg. #1

623

3.1#

MTS

Matsusaka Office, Mie
Prefecture

688

2.3

Note) Δ: epicentral distance, IJMA : JMA instrumental seismic intensity (using an asterisked sensor), Azimuth: clockwise direction
from North, H1, H2, V : maximum accelerations in horizontal #1 (Azimuth), horizontal #2 (Azimuth+90°) and vertical#directions, : calculated from two horizontal accelerations because of trouble on the vertical sensor

9

Table 2.1
CodeStrong motion records obtained by BRI strong motion network (4/4)
Station nameΔ (km)IJMA

Azimuth085°

MIZ

Maizuru City Hall

726

0.9

OSK

Osaka Government Office Bldg.
#3

759

2.9

SKS

Sakishima Office, Osaka
Prefecture

770

3.0

Max. Acc. (cm/s2)
H1
H2
V
1
2
2
1
1
2
65
38
7
11
9
5
35
33
80
41
38
61
85
57
18
127
88
13
129
85
12

Loc.

01F
05F*
18F
189°
B3F*
01F*
18F
229° 38F
52FN
52FS

Note) Δ: epicentral distance, IJMA : JMA instrumental seismic intensity (using an asterisked sensor), Azimuth: clockwise direction
from North, H1, H2, V : maximum accelerations in horizontal #1 (Azimuth), horizontal #2 (Azimuth+90°) and verticaldirections

2.4.1 Strong
buildings

motion records

44˚of damaged

43˚

HKU

KGC
HRO

42˚

Among buildings in the BRI Strong Motion
Network, at least 4 buildings suffered severe
earthquake motions and then some damage. One
example of the damaged buildings is the buildingof the Human Environmental Course, Tohoku
University. This is the 9-story steel reinforced
concrete (SRC) school building that is located in
the Aobayama Campus. This building has a long
history of strong motion recordings. Amongthem, strong motion records on the ninth floor of
the building that were obtained during the 1978
Miyagi-Ken-Oki earthquake are well known tohave represented a maximum acceleration of
more than 1000 cm/s2.

HKD

41˚
HRH

40˚

HCN2, HCN
MYK

AKT

39˚
TRO

38˚

NIG

THU,
SND

37˚

2011/03/11
14:46(JST)h=24 km, M9.0

IWK
NGN

36˚
MIZ

35˚

OSK,
SKS
MTS

KSO
YMN
NGY SMZ

km

SMS

34˚
134˚ 135˚ 136˚ 137˚ 138˚ 139˚

0

100

200

140˚ 141˚ 142˚ 143˚ 144˚ 145˚ 146

˚Fig.2.4 Locations of Epicenter ( ) and Strong
Motion Network ( )During the Tohoku earthquake, multi-story shear
walls suffered flexural failure and other damage.
The appearance of the building is shown in Photo
2.1, and strong motion records obtained during
the main shock in Fig. 2.6. This figure shows (a)acceleration waveforms in the transverse
direction, (b) acceleration waveforms in thelongitudinal direction, (c) building displacementin the transverse direction (relative displacement
to first floor of the 9-story building), (d) building
displacement in the longitudinal direction, and(e) fundamental natural periods of the buildingthat were calculated every 10 seconds [2.3].

Thick and thin lines in Fig. 2.6 (a) and (b)represent acceleration waveforms on the first andthe ninth floors, respectively. Maximum
accelerations on the first floor exceeded 330
cm/s2 in both of the directions. A maximum
acceleration on the ninth floor was 2 to 3 times
larger than on the first floor, and exceeded 900
cm/s2 in the transverse direction. The
fundamental natural periods in Fig. 2.6 (e)represented about 0.7 seconds at the initial stageof the earthquake motion in both of the directions,but increased to about 1 second in the first wave
group at the time of 40 to 50 seconds, andincreased from 1.2 seconds to about 1.5 seconds

10

1000
Acc (cm/s2)

in the second wave group at the time of 80 to 100
seconds. Due to the seismic damage, thefundamental natural period finally became twice
longer than that at the initial stage, and was
reduced to 1/4 on a stiffness basis.

Acc (cm/s 2)

−1000
1000

Disp (cm)Disp (cm)(b) Acc. in Long. Dir.

09F(Long.)
01F(Long.)(c) Bldg. Disp. in Trans. Dir.

0

−40
40

(d) Bldg. Disp. in Long. Dir.

0

−40
2.0
T (s)

09F(Trans.)
01F(Trans.)

0

−1000
40

An additional comparison was made in Fig.2.7.
The 1978 record at the 1st floor was comparedwith the 2011 record in velocity. The differenceis clear that the earthquake size was different andthe duration time of the 2011 Tohoku earthquake
was much longer.

(a) Acc. in Trans. Dir.

0(e) Transition of natural periods

1.5
1.0
Trans

Long.

0.5
0

36˚20'

50

100
Time (s)150200Fig. 2.6 Strong Motion Records of the Human
Environmental Course, Tohoku University andTransition of Natural Periods with Time

ANX, BRI
TKC
NIT
SITA, SIT2
UTK,
NMW,
SMD
KDI

35˚40'

80

TUS
Velocity (cm/s)

36˚00'

TDS
MST
AKB
ADC
EDG

YCY
TKD ICKFNB
CHB
TUF

NKN

CGC,
CG2,
CG3 KWS

0-20

2011.3.11 Tohoku Eq. (main shock)00

139˚40'

20

-40

km

35˚20'
139˚20'1978.6 Miyagi-ken-oki Eq

6040

140˚00'

100

150
time (s)

200

250

300

Fig.2.7 Comparison of the Recorded Motions at
the 1st floor of Tohoku University Building
between 1978 Miyagi-Ken-Oki and 2011 Tohoku
earthquakes

50

140˚20'50

140˚40'Fig. 2.5 Strong Motion Network in Kanto Area
(corresponds to green rectangle in Fig. 2.4)

2.4.2 Long-period earthquake motions in Tokyo
and Osaka Bays
Long-period earthquake motions and responsesof super high-rise buildings that are shaken underthe motions have been socially concerned inrecent years. When the Tohoku earthquake
occurred, long-period earthquake motions wereobserved in Tokyo, Osaka and other large cities
that are away from its hypocenter. This section
presents two cases in Tokyo and Osaka from the
BRI strong motion network.
Photo 2.1 Appearance of the Building of the
Human Environmental Course, Tohoku
University

First, a 37-story reinforced concrete (RC) superhigh-rise building (TKD in Table 2.1) on the
coast of Tokyo Bay is introduced. Fig. 2.8 showstime histories of displacement (in two horizontal
directions of S-N and W-E) that were calculated
from the integration of acceleration records on
the 1st and 37th floors in this building, andbuilding displacements that were calculated by11

Disp. (cm)Disp. (cm)Disp. (cm)Disp. (cm)Disp. (cm)Disp. (cm)Disp. (cm)52F SW-NE (peak: 137.1 cm)

052F NW-SE (peak:- 83.7 cm)

0

-200
200

Disp. (cm)

01F S-N (peak:- 20.5 cm)

52F-01F SW-NE (peak:- 138.2 cm)

0

-200
200

01F W-E (peak:- 17.6 cm)

0
-50
50

01F NW-SE (peak: 7.8 cm)

0

-200
200

0
-50
50

01F SW-NE (peak:- 9.1 cm)

0

-200
200

Disp. (cm)

50 Displacement

200 Displacement

-200
200

Disp. (cm)Disp. (cm)Disp. (cm)subtracting the displacements on the 1st floor
from those on the 37th in the two horizontal
directions. A maximum value of ground motion
displacement was about 20 cm. It is understoodthat the ground in itself was greatly shaken. A
displacement of the building in itself that wascaused by its deformation reached 15 to 17 cm.

52F-01F NW-SE (peak: 84.8 cm)

0

-200

37F S-N (peak:- 32.1 cm)

0

100

200

300

400

500

600

700

Time (s)0-5050Fig. 2.9 Displacement Waveforms observed at a 55story Office Building in Osaka Bay Area

37F W-E (peak:- 27.9 cm)

0
-50
50

In order to examine the properties of earthquake
motions on both of the coasts of Tokyo Bay andOsaka Bay, pseudo velocity response spectrawith a damping ratio of 5% of strong motion
records that were obtained from the 1st floors inthe buildings at the two locations are shown in
Fig. 2.10. The response spectrum (left) in therecords on the coast of Tokyo Bay had a peak at
a period of 1 to 1.2 seconds, at 3 seconds and at 7
seconds, but a relatively flat shape in general.

37F-01F S-N (peak:- 14.7 cm)

0
-50
50

37F-01F W-E (peak:- 16.7 cm)

0
-50
0

100

200

300

400

500

600

700

Time (s)Fig. 2.8 Displacement Waveforms observed at a
37-story Residential Building in Tokyo Bay Area
Fig. 2.9 shows strong motion records that wereobtained from the 55-story steel office buildingon the coast of Osaka Bay that is 770 km awayfrom the hypocenter. This figure shows absolute
displacements in the SW-NE and in the NW-SE
directions on the 1st floor, absolute
displacements in both of the directions on the
52nd floor, and building displacements (relative
displacements of 52th floor to 1st floor) in bothof the directions, from the top to the bottom. A
ground motion displacement was not large, orless than 10 cm, but the 52nd floor in thebuilding suffered a large motion with a zero-topeak amplitude of more than 130 cm.

On the other hand, the response spectrum (right)
in the records on the coast of Osaka Bay had alarge peak at 7 seconds, and amplitude of the
response was not much different from on the
coast of Osaka Bay. The coincidence of thefundamental natural period (6.5 to 7 seconds) in
the steel office building with a predominantperiod of the earthquake motion is considered tohave caused a resonance phenomenon and thenlarge earthquake responses were observed at the
top.

12

0
10
0

10
0

10
s)
/s/
cm

s)
/s/
cm
1(

S-N
W-E

1
0.5

SW-NE
NW-SE

1
Period (sec)

5

10

0.1

1

)
m

0.5

0.

(c
01
0.

1

)
m

0.

(c
01
0.

0.1

1

0.5

5

1

1

10

10

5

10

1(

10

Pseudo Velocity Response (cm/s)

50

10

50
Pseudo Velocity Response (cm/s)

Pseudo Vel. Resp. Spectrum (h=5%)

10
0

100

10
0

Pseudo Vel. Resp. Spectrum (h=5%)
0

100

0.5

1
Period (sec)510

Fig. 2.10 Pseudo velocity response spectra with damping ratio of 5% of records in Tokyo
Fig. 2.10 Pseudo
Velocity Response Spectra with Damping Ratio of 5% of Records in Tokyo Bay Area
(left) and Osaka Bay Area (right)

3. DAMAGE OF BUILDINGS DUE TO
EARTHQUAKE MOTIONS

including inland Tochigi Prefecture that sufferedlarger damage than coastal prefectures. In
addition, as a secondary investigation, weplanned to select affected areas from thosesubject to the primary investigation to conduct a
more detailed survey on houses collecting houseplans and layout of wood-shear-walls.

3.1 Policy for Earthquake Damage Investigationfor Buildings
The Tohoku Earthquake brought about building
damage in a wide area of various prefectures on
the Pacific coast in eastern Japan such as Iwate,
Miyagi, Fukushima, Ibaraki and Chiba.

In order to conduct a damage investigation ofsteel buildings, it was decided that mainly a
primary appearance investigation would be donein Sendai City with a large stock of steelbuildings, and in Fukushima and Ibaraki
Prefectures. As mentioned later, significant
damage of structural elements was visuallylimited, while there were so many types ofdamage of nonstructural elements such as fallingof exterior cladding. Consequently, focusing not
on private buildings that are difficult toinvestigate but on school gymnasiums in Ibaraki
Prefecture where many damage cases werereported that enable interior investigations, we
decided to continue the primary investigation.
For reference, the school gymnasiums can beseen to be similar to factories and warehouses. If
the structural damage in interior building isclarified in future, more detailed investigation as

An epicentral region of this earthquake has alength of about 450 km and a width of about 150
km, almost in parallel with the Pacific coast ineastern Japan. A distance from the fault plane tothe above prefectures is almost same. Observed
earthquake motions in Sendai City close to theepicenter are not much different from those in acity far away from Sendai, for instance, Tsukuba
City.
Based on these circumstances, we decided towidely survey damaged wood houses as a
primary damage investigation in the northernpart of Miyagi Prefecture (Kurihara City) where
JMA Seismic Intensity 7 was observed, and in awide area of Miyagi to Ibaraki Prefectures13

a secondary investigation on buildings other than
the gymnasiums will be considered.

and Hitachiota City and Naka City in Ibaraki
Prefecture: As a result of damage survey byothers [3.2], damage information has neverbeen reported, at the time of our survey.
- Ishinomaki City in Miyagi Prefecture:
Although it was almost included in the belt ofseismic center, the area of the city was not
flooded by the tsunami.
- Joso City and Ryugasaki City in Ibaraki
Prefecture: We had damage information in theneighborhood of NILIM and BRI.

For a damage investigation for reinforced
concrete buildings, in addition to an investigationof reportedly collapsed buildings, a primary
investigation will be conducted on city halls andother public buildings that located in a wide areaof the north to the south as done in the damage
investigation for wood houses, and damage
patterns whether they are similar or different
from previously grasped patterns are examined.
If there are characteristic damage patterns thatshould be incorporated into technical standards,
the secondary investigation will be considered.

The positions of the surveyed cities and towns
are shown in Fig. 3.1.
<Miyagi Pref.>Kurihara City,
Osaki City
Misato Town
Ishinomaki City
Aoba Ward,
Sendai CityA primary investigation for damage of building
lands and foundations will be conducted in Itako
City, Ibaraki Prefecture, and in Urayasu City,
Chiba Prefecture and its peripheral areas that was
subject to severe liquefaction in the region of
Kanto Area. The areas that had been affected by
the 1978 Miyagi-Ken-Oki earthquake weredamaged again. In these areas, also a primarydamage investigation that focuses on developed
housing lands will be conducted in some areas of
Miyagi, Fukushima and Tochigi Prefectures.

<Fukushima Pref.>Sukagawa City,<Tochigi Pref.>Nasu Town,
Yaita City

In order to survey the damage of nonstructuralelements, a primary investigation will be
performed,
altogether
withadamageinvestigation for steel and reinforced concretebuildings including a requested investigation ofceiling falls in the Ibaraki Airport Building as anadministrative support.

<Ibaraki Pref.>Hitachiota City,
Naka City
Mito City
Joso City
Ryugasaki City
Fig. 3.1 Positions of Surveyed Cities and Towns

3.2 Damage of Wood Houses

3.2.2 Results of the survey

3.2.1 Introduction(1) Kurihara City, Miyagi Prefecture

The survey area and the reasons of the choice areas follows;- Kurihara City in Miyagi Prefecture: The
seismic intensity 7 was recorded.
- Osaki City in Miyagi Prefecture: As a result of
damage survey by others [3.1], heavy damage
was reported,- Sukagawa City in Fukushima Prefecture: RCbuildings were heavily damaged.
- Nasu Town and Yaita City in Tochigi Prefecture,

K-NET Tsukidate (MYG004 ： Instrumental
seismic intensity 6.6) is set up on the hillock
about 3m higher than southern parking lot of
Kurihara lyceum. There was a possibility of theamplification of earthquake motions. In
Wakayanagi, the ground was bad and Sand
eruption by liquefaction was observed. Damageof houses caused by ground transformation(Photo 3.1) and houses with store were also
observed (Photo 3.2).

14

Great residual deformation was observed in thelongitudinal direction in the large-scale woodbuilding used to be a movie theater thenrenovated to a factory (Photo 3.3)

combined house) (Photo 3.6) with story shear
deformation whose exterior mortar came off andwood lath under the mortar near the opening of
the ventilation fan were deteriorated and attacked
by termites. Such damage was confirmed in theother buildings. Most of these damage occurredalong the small river, except for a few case, andit was considered that the soft ground near theriver might amplify the earthquake groundmotion.
The rare damage example (Photo 3.7) that only
the 2nd story collapsed was observed.

Photo 3.1 Damage of Houses caused by Ground
Transformation

Photo 3.4 Warehouse with Mud Walls damaged
Heavily or Slightly
Photo 3.2 Damage of Houses with Store

Photo 3.5 Warehouse with Mud Walls whose
Roof System with Roof Tiles fell down
Photo 3.3 Large-scale Wood Building renovatedto a Factory(2) Osaki City, Miyagi Prefecture
Every warehouse with the mud walls renovatedas store or gallery (Photo 3.4) were damaged
heavily or slightly. There was the one whose roof
system with roof tiles collapsed and fell down, as
shown in Photo 3.5. There was the house for
combined residential and commercial use (=store

15

Photo 3.6 Store Combined House with Story
Deformation

Photo 3.9 Damage of House

Photo 3.7 School Building whose2nd Story
Collapsed

Photo 3.10 Damage of House caused by the
Ground Transformation (Oritate)(3) Sendai City, Miyagi Prefecture
From the results of investigations on Oritate andSeikaen where the damage of the houses wereserious, it was found that almost all of thedamage of houses were caused by groundtransformation. Moreover, ground transformation
caused retailing wall collapse (Photos 3.8, 3.9),
landslide and damage of houses (Photo 3.10). In
Komatsujima, Aoba ward, drop off the mortar
wall and damage of columns and by biodeterioration and termite were observed in thehouse with shop (Photo 3.11).

Photo 3.11 Drop Off the Mortar Wall
(Komatsujima)(4) Sukagawa City, Fukushima Prefecture
A lot of damaged wood houses were foundaround the collapsed reinforced concretebuilding. For instance, they were the fallen
mortar wall of the second floor of dwelling withshop (Photo 3.12), several decay and Japanese
subterranean termite’s damage on frame andwood sheathing of mortar wall (Photo 3.13).
The Dozo (Japanese traditional wood storehousecoated with clay and plaster finish) was greatly
damaged around the hotel that the window glass

Photo 3.8 Damage of Retaining Wall and Houses（Oritate, Aoba Ward）

16

was broken, and it had residual deformation(Photo 3.14). The damage of roof’s collapsing of
the Dozo (Photo 3.15) was also found.
The sand eruptions from liquefied ground andthe damage of the roof tile were seen here andthere in some places at Minami-machi,
Sukagawa City.
Photo 3.15 Fallen Roof Tile of Dozo(5) Hitachiohta City, Ibaraki Prefecture
There were a lot of damaged fence made by the
Ohyaishi stone. The collapsed farm type house
was observed (Photos 3.16, 3.17).

Photo 3.12 Fallen Mortar of Wall (Wood House
with Shop)

Photo 3.16 Collapsed Wood House

Photo 3.13 Bio-deterioration of Column andBased Mortar

Photo 3.17 Breakage of Entrance Part
(6) Naka City, Ibaraki Prefecture
Photo 3.14 Dozo with Residual Deformation

There were a lot of collapsed (Photo 3.18) or
heavily damaged barns. The damaged house withshop was observed (Photo 3.19). The two story
wood house with mortar finish collapsed at theurban area (Photo 3.20).

17

Prefecture, and Hitachiota City and Naka
City in Ibaraki Prefecture.
2) Though the seismic intensity 7 was recorded
in Kurihara City, Miyagi Prefecture, it was
felt that the damage on wood houses was not
so much.
3) The damage on the wood houses caused by
the failures of residential land was confirmed
in Sendai City, Miyagi Prefecture, and Yaita
City, Tochigi Prefecture. There were many
number of the damage as such, too.
4) The damage of the roof tile in Fukushima and
Ibaraki Prefectures was felt much larger than
Miyagi Prefecture where an earthquake
occurred frequently.
5) The possibility that the ground motion was
amplified on the land filled up from meadow
or rice field, even if the residential land did
not fail, was suggested in Kurihara City,
Osaki City in Miyagi Prefecture, Nasu Town
in Tochigi Prefecture, Hitachiota City, Naka
City, Joso City, Ryugasaki City in Ibaraki
Prefecture, and so on.
6) In Osaki City, Miyagi Prefecture, the plural
rare damage examples that residual story
deformation of 2nd floor was larger than thatof 1st floor were confirmed.

Photo 3.18 Collapsed Barn

Photo 3.19 Damaged House with Shop

The selected individual buildings will besurveyed in detail and each of the damage causes
will be discussed in future, based on the resultsof the damage summary of the above-mentioned
wood houses.
3.3 Damage of Reinforced Concrete Buildings

Photo 3.20 Collapsed House
3.2.3 Concluding remarks

3.3.1 Introduction

As a result of damage survey on the wood houses
due to ground motion in Kurihara City, Osaki
City, Misato Town, Ishinomaki City, Sendai Cityin Miyagi Prefecture, Sukagawa City in
Fukushima Prefecture, Nasu Town, Yaita City in
Tochigi Prefecture, and Hitachiota City, Naka
City, Mito City, Joso City, Ryugasaki City in
Ibaraki Prefecture, the followings were provided.
1) The damage on the many wood houses due toground motion was confirmed in Osaki Cityin Miyagi Prefecture, Sukagawa City in
Fukushima Prefecture, Nasu Town in Tochigi

The Tohoku earthquake widely caused a lot ofdamage to buildings in Tohoku and Kanto Areasof Japan. NILIM and BRI investigated thedamage of reinforced concrete (RC) buildings
and reinforced concrete buildings with embedded
steel frames (referred to as steel reinforced
concrete, or SRC) in the affected areas where theearthquake intensity was classified as JMA
seismic intensities 6+ and 6- in Iwate, Miyagi,
Fukushima and Ibaraki Prefectures. The
objective of the field investigation was to see thepicture of the outline of the overall damage on

18

the buildings and to classify the damage patternof them. The survey was conducted several times
from March 14 to the middle of May in the areas
as shown in Fig. 3.2. The outline of theinvestigation is described below.

Aoba,
Wakabayashi,
Miyagino
Ward, Sendai
Fukushima

investigations. Some serious types of damage
were observed, such as story collapse of low-risebuildings, collapse of soft-first story (pilotis),and the loss of vertical load carrying capacity ofcolumns due to shear failure. Most of severely
damaged buildings were designed with theprevious seismic design code that was governed
before June 1981. Some SRC buildings designed
under the current seismic design code, which has
been coming into force after June 1981, caused
damage of buckling of their longitudinal
reinforcements near base plates at the bottom ofcolumn. The same damage is known to haveoccurred also in the Kobe earthquake. In addition,buildings designed under the current seismic
design code were confirmed to have no collapse
but some damage like shear cracks at their beamcolumn joints or horizontal cracks at theirconcrete placing joints.

Tono
The 2011 off the
Pacific coast of
Tohoku EQ

Nihonmatsu
Shirakawa

Hitachiomiya

Koriyama
Sukagawa
HitachiKasamaHokotaThe types of the damage of RC and SRC
buildings that were observed through the site
investigation are classified into those forstructural and nonstructural elements in thefollowing.

Fig. 3.2 Investigated Area (add a postscript on
KenMap」)

A) Damage of structural elementsA-1) Collapse of first storyA-2) Mid-story collapseA-3) Shear failure of columnsA-4) Flexural failure at the bottom of column
and base of boundary columns on multistory shear wallsA-5) Pullout of anchor bolts and buckling of
longitudinal reinforcements at exposedcolumn base of steel reinforced concrete(SRC) buildingsA-6) Shear failure or bond splitting failure oflink beams of multi-story coupled shearwallsA-7) Building tiltingA-8) Destruction, failure or tilting ofpenthousesA-9) Damage of seismic retrofitted buildings

3.3.2 Characteristics of damage on RC buildings
In the earthquake, strong earthquake motions
were observed in various locations of the Tohoku
and the Kanto Areas and caused various types ofdamage in a wide area. At the same time, thedamage concentrated on specific areas was notseen generally. In general, we had the impressionthat structural damage was not particularly greatin comparison with JMA seismic intensities
measured in the locations. Consequently, there is
not a significant difference in damage situations
among the locations. However, the damage tostructural members was somewhat concentrated
on limited areas, such as Wakabayashi Ward in
Sendai City and Sukagawa City. It is known thatthese areas formed paddy fields or moats.
Therefore, it can be well estimated that groundconditions in the areas possibly contributed tothe damage.

B) Damage of nonstructural elementsB-1) Flexural failure at the bottom of column
with wing wallB-2) Damage of nonstructural wall inresidential building

The types of structural damage on RC buildings
identified by the field surveys are those that had
been observed in past earthquake damage19B-3) Damage and falling of external finishingB-4) Tilting or dropout of components
projecting above the roofB-5) Collapse of concrete block wall andstone masonry wallstory has openings on the wall at the gable side,
as shown on the left wall of Photo 3.23. For thisreason, it was assumed that the openings wereintensively deformed and resulted in shear failureof the short columns formed by hanging andspandrel walls. Shear failure of the long columnson the third story was observed possibly due tothe effect of the collapse of the second story.
Damage of the columns and beams on the firststory was not seen, while shear cracks wereobserved on the nonstructural walls.

3.3.3 Damage of structural elementsA-1) Collapse of first story
The 3-story RC building which was at theintersection in Sukagawa City, having a few
walls on the facade on the first story and manywalls on the back of the first story and the second
story and higher, was severely damaged on thefirst story. The corner columns faced theintersection were significantly destroyed. The
loss of axial load carrying capacity of the firststory columns caused the drop of the second andhigher stories (Photos 3.21 and 3.22).

Photo 3.23 Mid-story Collapsed BuildingA-3) Shear failure of columns
The shear failure occurred on the first-story
columns in the two-story RC building in Aoba
Ward, Sendai CIty (Photos 3.24 and 3.25). Somecolumns of the building were intact after themain shock on March 11, but aftershocks caused
shear failure to some of them, as shown on theright of Photo 3.25. It was confirmed that theaftershocks accelerated the damage level of thisbuilding.

Photo 3.21 First-story Collapsed Building

Photo 3.22 Close-up View of the Fallen Story
A-2) Mid-story collapse

Photo 3.24 Appearance of Damaged Building

The 3-story office building in Wakabayashi Ward,
Sendai City partially collapsed on the second
story and tilted (Photo 3.23). Only the second20A-4) Flexural failure at the bottom of column
and base of boundary columns on multi-story
shear walls

caused byaftershocks

The building that consists of 9-story SRC and 2story RC structures in Aoba Ward, Sendai City
suffered from the earthquake (Photo 3.28). In thehigh-rise building, the multi-story shear wall on
the gable side was subject to flexural failure at
the third floor. Crushing of concrete and bucklingof the longitudinal reinforcements were observedat the bottom of the boundary column of shear
wall, as shown in Photo 3.29. This building was
also damaged by the Miyagi-Ken-Oki earthquake
in 1978 and had been retrofitted.

Photo 3.25 Shear Cracks on First-story Columns
The 3-story RC building constructed in 1964 ona hill in Kasama City suffered also damage.
Cracks in the ground were observed around thebuilding. As seen in the photo, the RC structureon the first story was greatly damaged. Shear
failure occurred on many exterior columns,
which were made shorter in clear height by thehanging and spandrel walls without structural slit,
as shown in Photo 3.26. In addition, the failuresof the shear walls with openings were observed(Photo 3.27)

Photo 3.28 Appearance of Damaged Building

Photo 3.26 Shear Failure of Column

Photo 3.29 Crushing at the Bottom of Column on
the Multi-story Shear WallA-5) Pullout of anchor bolts and buckling of
longitudinal reinforcements at exposed columnbase of steel reinforced concrete (SRC) buildings
The damage at the bottom of SRC column andshear wall was observed too on the building in
Shirakawa City (Photo 3.30), which was

Photo 3.27 Shear Failure of Wall with Opening

21

composed of RC and SRC structures. Pullout ofanchor bolts of the exposed-type column base
was detected. In consequence, the reinforcing
bars were forced to stretch large and the bucklingof them occurred around the base plate, as shownin Photo 3.31.

This type of damage was observed not only
in buildings designed under the previous
seismic design code but also in somebuildings done under the current seismic
design code.

Photo 3.32 Appearance of Damaged Building

Photo 3.30 Damage on the Bottom of SRC
Column and Shear Wall

Photo 3.33 Damage on Boundary Beam with
OpeningA-7) Building tilting
Photo 3.34 shows a residential building that sankand leaned in the longitudinal direction in
Shirakawa City. The balcony, of which height
above ground level was about 77cm, went down
to ground surface in the gable side, as shown in
Photo 3.35. Significant settlement was observed
too on foot walk in surrounding area.

Photo 3.31 Close-up View of the Bottom of SRC
ColumnA-6) Shear failure or bond splitting failure oflink beam of multi-story coupled shear walls
The shear failure or bond splitting failure
occurred on the link beam connecting coupledshear walls from low-rise to high-rise stories on
the 8-story RC building in Aoba Ward, Sendai
City, as shown in Photo 3.32. The link beams has
two openings at the center of them, and weredamaged around these parts (Photo 3.33).

22

the building was below the seismic demandindex of structure, IS0 by the seismic evaluation
method [3.3]. Meanwhile, the building in the
span direction was not retrofitted, as aconsequence of that the seismic index ofstructure in the direction satisfied the seismic
demand index of structure. The steel braces are
eccentrically installed to the center axis of thebeams and columns.
Shear cracks occurred on the columns with theframed steel braces at the earthquake, as shownin Photo 3.38, although the remarkable damage
such as yield of steel were not seen on the braces.

Photo 3.34 Appearance of Sank and Leaned
Building

Photo 3.35 Sank BalconyA-8) Destruction, failure or tilting of penthouses

Photo 3.37 Appearance of Damaged Building

The damage on penthouses was observed
everywhere, like tilting of it in Aoba Ward,
Sendai City, as shown in Photo 3.36.

Photo 3.38 Shear Crack on Column with Framed
Steel Braces

Photo 36 Damaged Penthouse

There were many seismic retrofitted buildings
including school buildings in the affected areas
where the great earthquake motions wereobserved. Based on the results of ourinvestigation, these retrofitted buildings werehardly damaged or slightly harmed, it means thatthe seismic strengthening on existing buildings
worked effectively against the earthquake.

A-9) Damage of seismic retrofitted buildings
Photo 3.37 shows the 2-story RC office building
constructed in 1969 in Hitachiomiya City. The
building was retrofitted with framed steel bracesin the longitudinal direction in 2003, because theseismic index of structure, IS on the first story of23

3.3.4 Damage of nonstructural elementsB-1) Flexural failure at the bottom of column
with wing wall
The separation of cover concrete at the bottom ofwing wall was observed on the 5-story RC
building constructed in 2007 in Sukagawa City
(Photo 3.39). In here, we classified this as thedamage of nonstructural elements, because thewing wall is generally designed as thenonstructural element, which is not expected toresist the external force.

Photo 3.40 Appearance of Damaged Building

Photo 3.41 Shear Failure of Nonstructural Wall
Photo 3.39 Separation of Concrete of Wing WallB-2) Damage of nonstructural wall in residentialbuilding
The nonstructural walls around the front doors
from low-rise to top floors were subject to shear
failure, while the doors were deformed on the
10-story SRC residential building constructed in
Aoba Ward, Sendai City in 1996, as shown in
Photos 3.40 and 3.41. In addition, shear cracks
were observed on the mullion walls on balconies
in some of the low-rise floors.

Photo 3.42 Shear Crack on Nonstructural WallB-3) Damage and falling of external finishing

The shear cracks on the mullion walls also
occurred in the 8-story RC hotel in Sukagawa
City (Photo 3.42).

Photos 3.43 show the case where the autoclaved
lightweight aerated concrete (ALC) panel on theupper floor in the 8-story building fell away, andPhoto 3.44 is the case where the tile on exteriorwall was dropped, in Aoba Ward, Sendai City.

The cases where shear cracks occurred on the
nonstructural walls around the front door or on
the mullion wall on the balcony were relatively
often observed in urban residential buildings,
regardless of the seismic design codes applied to.

These kinds of damage relatively often occurredin buildings without structural damage, notlimited to specific areas. Despite of the24construction period and the seismic design codes
applied to, these damage are often seen in manybuildings.

Photo 3.46 Collapse of Stone Masonry Wall
3.3.5 Concluding remarks
Photo 3.43 Dropped ALC Panels from 8 Story

We classified the types of damage of reinforced
concrete (RC) and steel reinforced concrete(SRC) buildings that were caused by earthquake
motions under the Tohoku earthquake, anddescribed the damage on structural andnonstructural elements. As mentioned early,
almost all of the types of damage were observedin past destructive earthquakes such as the Kobe
earthquake in 1995 and the Mid Niigata
Prefecture earthquake in 2004. However, thefollowing types of structural damage that wereobserved in the Kobe earthquake have not been
confirmed within the scope of the investigation
conducted so far.
- Story collapse of soft-first story building
designed under the current seismic designcode- Mid-story collapse in mid-rise and high-risebuildings- Overturning of buildings- Failure of beam-column joint in building
designed under the current seismic designcode- Fractureofpressure
weldingofreinforcements- Falling of pre-cast roof in gymnasium

Photo 3.44 Damage of Tile on Exterior WallB-5) Collapse of concrete block wall and stone
masonry wall
The collapse of concrete block wall and stone
masonry wall are well known as earthquake
damage caused by strong seismic motion. The
damage of those was often observed in the field
investigation, as shown in Photos 3.45 and 3.46.

In general, there are only a few cases of serious
structural damage that was caused by earthquake
motions. On the contrary, it was the remarkablecases caused by the earthquake that publicbuildings like city hall under the past seismic
design code suffered from severe damage andcould not be continuously used. The main causeof the damage on these buildings was the loss ofthe vertical load carrying capacity due to shear

Photo 3.45 Collapse of Concrete Block Wall25

failure of short columns. The fact makes us
reconfirm that seismic retrofit on these buildings
is particularly important, which must be operated
as the disaster-prevention facilities.

The main purpose of the investigation is todetermine what damage pattern was often
distributed in these areas and in which area thepattern was often distributed. A total of 44
gymnasiums in high schools were chosen andinvestigated.

3.4 Damage of Steel Gymnasiums
3.4.1 Introductionii) Outline of damage investigation for elementaryand junior high school gymnasiums in Mito City

The damage of general steel buildings such as
offices and shops caused by the Tohoku
earthquake in the areas of Ibaraki, Fukushima
and Miyagi Prefectures with JMA seismic
intensity around 6 was investigated for some two
weeks after the earthquake. The structures ofsteel buildings are generally covered withexterior cladding and interior finishing. For thisreason, the real situations of the damage tocolumns, beams and braces may not be correctly
determined under the exterior damage
investigation.
Therefore,thedamageinvestigation on steel gymnasiums whose
structural members are generally exposed wasconsidered and conducted. The damage
investigation for such steel gymnasiums was
carried out in the areas of Ibaraki Prefecture with
JMA seismic intensity around 6. This section
describes the outline of the damage investigation
for the steel gymnasiums.

In general, building size (total floor area) of highschool gymnasiums seems to be larger thanelementary and junior high school gymnasiums.
In order to know an effect of building size onearthquake
damagesituation,
damageinvestigation of elementary and junior highschool gymnasiums was considered andconducted. The result of the damage investigation
for the high school gymnasiums in Ibaraki
Prefecture showed that the areas around Mito City
suffered relatively larger structural damage thanother areas. Then, Mito City was chosen for thesurvey area of the damage investigation for
gymnasiums in elementary and junior high school.
A total of 22 gymnasiums in elementary andjunior high school constructed under the previous
seismic code in Mito City were investigated.
3.4.3 Classification and characteristics of damageof steel gymnasiums

3.4.2 Outline of damage investigation for steel
gymnasiums

For this earthquake damage investigation, a totalof 66 gymnasiums in the high schools within
Ibaraki Prefecture and in the elementary andjunior high schools within Mito City weresurveyed. The damage of the gymnasiums wasclassified into the types of (1) to (7). The types of(1) to (6) and the type of (7) refer to structural
damage and to nonstructural one, respectively.
(1) Buckling and fracture of brace member andfracture of its joint(2) Buckling of diagonal member of latticed
column(3) Damage of connection (bearing support part)
between RC column and steel roof frame(4) Deflection, buckling and fracture of roof
horizontal brace(5) Cracking of column base concrete(6) Other (Overturning of floor strut, etc.)i) Outline of damage investigation for highschool gymnasiums in Ibaraki Prefecture
Gymnasiums designed under the previous seismiccode were greatly damaged in the Mid Niigata
Prefecture earthquake in 2004, but most of themunder the current seismic code were not damaged[3.4, 3.5, 3.6]. Consequently, as the subject of thedamageinvestigation,
steel
gymnasiums
constructed under the previous seismic code weremainly chosen. The investigation covered a wide
range of areas in Ibaraki Prefecture where JMA
seismic intensity 5+ to 6+ was recorded (Ooarai
Town, Shirosato Town, Hitachi City, Mito City,
Naka City, Hitachinaka City, Chikusei City,
Kasama City, Hokota City, Tsuchiura City, Bando
City, Koga City, Shimotsuma City and Joso City).

26

(7) Nonstructural damage such as dropping of
ceilings and exterior walls and breakage ofwindows
Each damage photograph is shown for eachdamage type in the following.
(1) Buckling and fracture of brace member andfracture of its joint
Buckling of brace member (Photo 3.47) andfracture of brace joint (Photos 3.48-3.50) wereobserved. Angle section was often used for many
brace members, but circular hollow section steel(Photo 3.49) was also used for brace members.
Fractured sections include steel plate inserted into
steel pipe, end of bracing member and section
loss part by bolt hole. These types of the damage
are classified into the severe damage category
based on the damage evaluation standard [3.7].
The gymnasiums constructed under the previous
seismic code that were severely damaged by the
Mid Niigata Prefecture earthquake in 2004 had
accounted for about 30% of the total [3.4, 3.5,
3.6]. It is impressed that a rate of the gymnasiums
severely damaged by the Tohoku earthquake waslower than by the Mid Niigata Prefectureearthquake in 2004.

Photo 3.48 Net Section Fracture at Bolt Holea) Fracture at column top b) Fracture at brace crossing

Photo 3.49 Fracture of Brace Welded Connection

Photo 3.50 Fracture of Bolts(2) Buckling of diagonal member of latticed
columnPhoto 3.47 Buckling of Brace

In one of the investigated gymnasiums, bucklingof diagonal members in some latticed columns
was observed (Photo 3.51). Damage of column
buckling caused in steel frames for span direction
had not been observed under the damage
investigations of the Mid Niigata Prefectureearthquake in 2004 [3.4, 3.5, 3.6].

27a) Latticed column b) Buckling of diagonal member

Photo 3.53 Fracture of Horizontal Brace

Photo 3.51 Buckling of Diagonal Member of
Latticed Column(5) Cracking of column base concrete(3) Damage of connection (bearing support part)
between RC column and steel roof frame

Damage of cracking of the column base concreteand mortar in the gallery of some gymnasiums
was observed (Photo 3.54). Concrete and mortarof steel column base at a ground level was also
cracked. However, almost all of these cracking
are classified into minor or slight damage.

In the investigated gymnasiums, exposure ofanchor bolts due to spalling of the concrete atconnection (bearing support part) between the
RC column and steel roof frame (Photo 3.52),
spalling of finish mortars on the RC column at
the roof bearing support part, pullout of hole-inanchors were observed. This type of the damage
was observed in some gymnasiums in thisdamage investigation.

Photo 3.54 Cracking of Column Base Concrete(6) Other (Overturning of floor strut, etc.)
As the other types of the structural damage, thefollowing damage was observed; (a) overturningof floor strut (Photo 3.55), (b) tilting of concrete
block self-standing wall and (c) peeling of paintsof beam member which was observed near the
top of the V-shaped roof beam or arch beam
(Photo 3.56). In terms of the peeling of paints, it
is undetermined whether a yielding occurred tothe beam member or not.

Photo 3.52 Spalling of Concrete(4) Deflection, buckling and fracture of roof
horizontal brace
Roof horizontal braces were damaged in 2 highschool gymnasiums and 5 elementary and juniorhigh school gymnasiums. Such damage mainly
occurred at horizontal braces with turnbuckles;
obvious deflection of the horizontal brace,
fracture at thread and fracture of bolt connections
were observed (Photo 3.53).

28

Photo 3.58 Dropping of Ceiling Materials

Photo 3.55 Overturning of Floor Strut

Photo 3.59 Breakage of Windows

Photo 3.56 Peeling of Paints of Beam
(7) Nonstructural damage such as dropping of
ceilings and exterior walls and breakage ofwindows

Photo 3.60 Falling of Exterior Finish Materials

The types of nonstructural damage ofgymnasiums include dropping of ceilings andlighting equipment (Photos 3.57 and 3.58),
breakage of windows (Photo 3.59), dropping of
exterior walls (Photo 3.60), dropping of interior
walls and eave soffit. In particular, the severe
damage such as dropping of extensive ceiling in
the high school gymnasiums was observed thanin the elementary and junior high school
gymnasiums.

3.4.4 Concluding remarks
Damage of the steel gymnasiums constructedunder the previous seismic code in the areas with
JMA seismic intensity around 6 in Ibaraki
Prefecture was investigated, and the outline of
the investigation was described in this section.
The results of the damage investigation of thesteel gymnasiums are summarized as follows.
a) Structural damage of the steel gymnasiums
1) The types of observed structural damage ofthe gymnasiums are classified into the following
six categories. (1) Buckling and fracture of brace
member and fracture of its joint, (2) Buckling of
diagonal member of latticed column, (3) Damageof connection (bearing support part) between RC
column and steel roof frame, (4) Deflection,
buckling and fracture of roof horizontal brace,

Photo 3.57 Dropping of Ceiling Materials

29

(5) Cracking of column base concrete, and (6)Other (overturning of floor strut, etc.).

3.5.2 Liquefaction damage of catchment basin
area of Tone River

2) In 3 of the investigated 66 gymnasiums,
severe structural damage such as "fracture ofbrace member and joint" occurred. This rate ofthe damage seems to be smaller than that in the
Mid Niigata Prefecture earthquake in 2004.

Damage associated with liquefaction has
occurred in the same areas as in the areas whereliquefaction was reported in past earthquakes,
such as old river channel, reclaimed lagoon,reclaimed pond and reclaimed paddy field. Thissection describes the damage situations in
Nishishiro, Inashiki City, in Hinode, Itako Cityand in Kamisu City within Ibaraki Prefecture.
For reference, liquefaction damage in Nishishiro,
Inashiki City and in Hinode, Itako City wasreported after the 1987 East off Chiba Prefectureearthquake.

3) Severe structural damage was observed in
Mito City, Hokota City and Naka City than inother areas.
b) Nonstructural
gymnasiums

damage

of

the

steel

1) The types of observed nonstructural damage
include dropping of ceilings, dropping of exterior
and interior walls, falling of eave soffit andbreakage of windows.

(1) Nishishiro, Inashiki City in Ibaraki Prefecture
Large-scale and extensive damage occurred
within the zone of about 500 m four directions
that encloses Route 51 of National Highway and
Yokotone River on the east of the road. Route 11
of Prefectural Road was closed to vehicles, andsand boiling, great road upheaval or severe
fissure that is associated with liquefaction wasseen mainly along the road. As a groundtransformation, the ground subsided up to about
40 cm, and transversely moved up to about 1 m.
Private automobile were buried in boiled sand to
the extent of a half of height of their tires. This
indicates a great amount of sand boil.

2) In 4 of the investigated gymnasiums, ceilingmaterials were extensively dropped, which isclassified into the severe damage category. In
some of the gymnasiums, many windows werebroken.
3) Severe nonstructural damage was observed in
Mito City, Hokota City and Hitachi City than inother areas.
4) Severe structural and nonstructural damage
seems to occur in the high school gymnasiums
rather than in the elementary and junior highschool gymnasiums.

Finishes of the sidewalks around a large-scalecommercial establishment along Route 11 ofPrefectural Road were scattered. The subsidenceof the surrounding ground was about 40 cm, andthe settlement of the facility in itself was slight.
The commercial building was tilted about
0.7/100 in the longitudinal direction. We visuallyobserved a foundation type of the building froman opening between surrounding fissures. The
type was confirmed to be a pile foundation(Photo 3.61).

3.5 Damages due to Failures of Residential Land3.5.1 Introduction
This section reports the outline of damage
situations associated with liquefaction in thecatchment basin area of Tone River on the border
between Ibaraki and Chiba Prefectures and in
Urayasu City, Chiba Prefecture, and the outlineof damage situations of developed housing areain Miyagi and Fukushima Prefectures.

30

Photo 3.63 Subsidence of Two Houses enclosing
Vacant Land3.5.3 Liquefaction damage in Urayasu City, Chiba
Prefecture
A reclaimed ground accounts for 3/4 of a gross areain Urayasu City at present. The southern part of thiscity is an area that was developed under areclamation project using sea sand. In the result, thearea consists of a weak layer up to GL-40m. For
reference, liquefaction damage was reported after
the 1987 East off Chiba Prefecture earthquake. The
damage situations are given below.

Photo 3.61 Situations around the Commercial
Building and State of Pile Head
Sand boiling was seen everywhere on the roads orsites also in surrounding buildings lots. A house
constructed on an embankment was tilted to an
adjacent warehouse with sand boiling. An angle oftilting was 5.0/100 (Photo 3.62). It can be assumed
that liquefaction occurred at the concentration of
the loads of two adjacent buildings and the house
was tilted to the direction.

(1) Mihama
In Mihama, subsidence and tilting that was caused
by liquefaction were observed in a house that has a
dry area in a basement (Photo 3.64). An angle oftilting of the house was about 3 degrees. It isconsidered that the basement was lifted and anotherremaining parts of the house subsided. Around thishouse, a house's site was totally covered withboiled sand, and a fence's foundation was deformed.
In addition, a carport in one building was ruptured
by liquefaction and moved (Photo 3.65). A unit of
the carport and the building was separated andmoved about 50 cm probably due to the movementof the ground associated with liquefaction.

Photo 3.62 House Tilted 5.0/100(2) Hinode, Itako City in Ibaraki Prefecture
In Hinode, large-scale damage occurred in on
corner within the zone of about 200 m four
directions near Hitachi-tone River. Sand boiling,
lift of buried structures, and subsidence or tiltingof power poles, which were caused byliquefaction, were seen everywhere on the roadand sites. Many buildings facing the roadsubsided 20 to 30 cm from the front sidewalk(Photo 3.63). For reference, foundation cracks or
gaps were not observed in the investigated range.

Dry area

Photo 3.64 Tilted House31

structural damage, structural great deformationand fractured foundation.

Photo 3.65 Moved Carport(2) Irifune

Photo 3.67 Damage of Retaining Wall and House
Movement and Tilting by Sliding and Ground
Transformation

In Irifune, a difference in settlement between
adjacent buildings on spread and pile foundations
was observed. The building on spread foundation
subsided about 35 cm from the front sidewalk,
while the building on pile foundation waselevated about 30 cm (Photo 3.66). Other settled
and tilted buildings were dottedPile foundation(2) Near Aoyama 2-chome and Midorigaoka 4chome, Taihaku-ku, Sendai City, Miyagi Pref.
This area is located at one corner of a large-scale
housing area where a contoured hill wasdeveloped. Ground transformation by sliding of
the housing site embankment to the slope
direction, and damage to the retaining walls byground transformation, were often observed. The
damaged area at 4-chome, Midorigaoka under
this earthquake was almost same as under the
1978 Miyagi-Ken-Oki earthquake. The land at 2chome, Aoyama is wavier than at 4-chome,
Midorigaoka. Near the zone of 2-chome,
Aoyama, large-scale sliding of the embankment
occurred (Photo 3.68). In this zone, large
deformation and damage were seen on both ofupper structures and foundations of houses on
the housing area. In other places withembankment sliding, deformation and damage ofupper structures of houses were observed, but it
seemed that there was limited significant damage
to foundations. Near 2-chome, Aoyama, aretaining wall for the housing area with a heightof over 5 m was damaged.

Spread foundation

Settlement
about 35cm

About
30cm

Photo 3.66 Difference in Damage between
Support Mechanisms
6.5.4 Damage of developed housing area
The damage investigation for developed housingarea was conducted in some areas of Miyagi,
Fukushima and Tochigi Prefectures, but thedamage in Miyagi and Fukushima Prefectures isreported in this section.
(1) Near 5-chome, Oritate, Aoba-ku, Sendai City,
Miyagi Prefecture
In one corner of a large-scale housing area,
where a slope in the N-NE direction had beendeveloped, ground transformation by sliding of
the housing site embankment to the slope
direction, and damage to the retaining walls byground transformation were often observed(Photo 3.67). Houses on the site were recognized
to have different damage patters, such as
movement, subsidence and tilting without

Photo 3.68 Group of Houses damaged by Sliding
and Ground Transformation32

(3) Near Numanoue, Fushiogami, Fukushim City,
Fukushima Prefecture

3.6 Response of Seismically Isolated Buildings
3.6.1 Introduction

This area is located at one corner of a large-scale
housing area where a hill was developed. The
result of visual inspection showed groundtransformation by land sliding on the slope of thehill. This ground transformation caused serious
damage to houses. In the result, some houses wasin a state of sliding on the slope of the hill (Photo3.69). On the other hand, houses near the top of
the hill suffered only damage associated withslighttransformationofhousingarea
embankment.

Miyagi Prefecture and nearby areas haveexperienced disastrous earthquakes frequently,
therefore, reflecting high consciousness ofearthquake risks, there are many seismicallyisolated buildings (SI buildings) constructed inthose areas. Investigation team was dispatchedon July 1st and 2nd in 2011 to observe
performance of SI buildings during the Tohoku
earthquake and ask persons in charge of thebuildings about the damage. In total, 16 SI
buildings in Miyagi Prefecture and 1 building in
Yamagata Prefecture were investigated.
3.6.2 Behavior of SI buildings(1) SI building Ai) Building information
The SI building A is a reinforced concrete officebuilding with 9-story super-structure and 2-story
basement, located in Miyagino in Sendai City
(Photo 3.70). The building was retrofitted byusing base isolation technique putting isolation
devices on the top of columns in B1F. The floor
plan has the 26.4 m × 54 m rectangular shapeand 40 high-damping rubber bearings (HRBs)
are installed.

Photo 3.69 Land Sliding on Slope on theSouthwest of the Hill and Sliding House
3.5.5 Concluding remarks
The outline of the damage situations in theinvestigate scope is as follows.

ii) Building performance during earthquake
Observation results are summarized as follows:a) According to the person in charge of thebuilding, no furniture was turned over and no
structural damage was observed.
b) However, some damage was observed at thecover-panels of fire protection and the
expansion joints near the boundary between
isolated and non-isolated floors (Photo 3.71).
It seems that parts of expansion joints were
not well operated due to the large
displacement of SI building floor during
earthquake.
c) The ground surrounding the building
partially subsided around 10 cm.

1) Damage caused by liquefaction:
In the catchment area of Tone River and thecoastal zone of Tokyo Bay, extensive damage
such as sand boiling or ground transformation
associated with liquefaction was confirmed.
Highly tilted buildings were seen, but visualcracks or fissures on the foundations investigatedwere not observed.
2) Damage to housing area:
Large damage with transformations such as
ground sliding was observed mainly in theelevatedanddeveloped
housing
area(particularly marginal part). In some areas,transformations occurred again in the developed
lots that had been affected by the pastearthquakes.

iii) Earthquake motion records
This building has accelerometers at B2F, 1F and

33

9F (top floor). Also, there is a scratch board in
B1F to record the displacement of isolation floor.
Furthermore, there is an accelerometer installed
by JMA in the basement of an adjacent building.
The maximum acceleration values of theseaccelerometers at main shock are listed in Table
3.1.

Table 3.1 Maximum Acceleration Values
Direction
Location
NS
EW
Vertical
[gal]
[gal]
Z [gal]Basement of
409.9
317.9
251.4
adjacent bldg.
B2F (below SI)
289.0
250.8
234.9
1F (above SI)
120.5
143.7
373.7
9F
141.7
169.9
523.9

From the trace on the scratch board installed on
the SI building floor, the maximum displacement
was estimated as around 18 cm at the main shock(on March 11, 2011) and around 10 cm at theaftershock (on April 7, 2011).

(2) SI building Bi) Building information
The SI building B is a 14-story reinforced
concrete building used for condominium, locatedin Miyagino in Sendai City (Photo 3.72). The
building has the U-shape plan and the corners of
the building are separated by expansion joints.
The NRBs, Lead dampers, U-shape steel
dampers are installed in the SI floor.
ii) Building performance during earthquake
Observation results are summarized as follows:a) According to the person in charge of thebuilding, no furniture was turned over and no
structural damage was observed inside ofrooms. However, the damage to the
expansion joint was observed.
b) Drop of the ceramic tiles on outer wall
(Photo 3.73) and shear crack on the wall in
the first floor parking space (Photo 3.74)
were observed. The subsidence of groundaround 10 cm was observed near the building.
c) No damage was found to NRBs by visualinspection (Photo 3.75), however, paint of Ushape dampers was peeled off (Photo 3.76)
and many cracks were found on Leaddampers (Photo 3.77).

Photo 3.70 Overview of SI Building A(a) Damage to the panel(b) Damage to the expansion joint

Photo 3.71 Damage near the Boundary between
Isolated and Non-isolated Floors

Photo 3.72 Overview of SI building B

34

Photo 3.73 Drop of Ceramic Tiles

Photo 3.77 Lead Damper and Crack on the
Surface
Photo 3.74 Shear Crack on the Wall
3.6.3 Concluding remarks
Investigation results of SI buildings in Miyagi
Prefecture and one SI building in Yamagata
Prefecture is summarized as follows:a) Super-structures of SI buildings sufferedalmost no damage even under strong shaking
with JMA intensity 6 upper. It verifies theexcellent performance of SI buildings.
b) There are 8 buildings with scratch boards tomeasure displacement of the SI building floor.
In most cases, the maximum displacement has
been estimated as around 20 cm. There is one
case with the maximum displacement
estimated over 40 cm.
c) In some buildings, damage was observed at
the expansion joints. It seems that parts ofexpansion joints were not well operated dueto the large displacement of SI building floor
during earthquake.
d) Subsidence of ground around the building
was observed in some buildings.
e) Many cracks were found in lead dampers.
These cracks might be increased by theaftershocks.
f) Peeling off of paint was observed widely for
U-shape steel dampers. In some cases,

Photo 3.75 NRB

Photo 3.76 U-shape Steel Damper

35

residual deformation of steel was remained.
3) Reinforced concrete structures: Most of
structural damages in reinforced concrete
structure were observed in the buildings designed
based on the old seismic codes. Though thenumber of damaged buildings is not large
compared to the seismic intensity, damage types
were mostly similar to the past seismic damages
that include severe damage such as loss of axial
force bearing capacity due to shear failure ofcolumns.

3.7 Conclusion
This section summarizes results of damage ofbuildings due to earthquake motion throughsurveys on wood houses, steel buildings,
reinforced concrete buildings, residential land,
foundation,
non-structuralelements
andseismically isolated buildings. The results can besummarized as follows even though it is in thestage of the Quick Report.

4) Residential land, Foundation: One of theobserved characteristics is liquefaction in wide
areas that could not be occurred in the pastearthquakes in Japan. Researches on themechanism and considerations of countermeasures will be necessary not only for
individual buildings but also for infrastructure
like roads and water supply and sewage systems.
In a part of residential land, heavy damage suchas collapse of ground was observed equal to thepast damaged earthquakes.

1) Wood houses: The damages of upper structure
were confirmed in several areas however thedamage of wood houses seems not so heavy as
an impression in Kurihara City where seismic
intensity 7 was recorded. Many damages ofstructure were observed due to deformation ofdeveloped residential land in Sendai City, Miyagi
Prefecture and Yaita City, Tochigi Prefecture.
The damage of roof tiles could be more observedin both Fukushima and Ibaraki Prefectures thanin Miyagi Prefecture where earthquakes were
frequently occurred since the 1978 Miyagi-KenOki earthquake. The damage types are almost
similar to those of the past earthquakes.

5) Damages of non-structural elements ofcomparatively old construction types wereconfirmed in many cases. In addition, break andfalling of non-structural elements at rather higher
parts were also confirmed.

2) Steel frame structures: There was almost no
damage of main steel structure members such ascolumns and beams. Damages of vertical braces’
rupture etc. were observed in the school
gymnasium that was constructed in the years ofold seismic code (before 1981) however thedamage ratio is smaller than the case of the
Niigata-Ken Chuetsu earthquake in 2004. On theother hand, damages of non-structural elements
including falling of ceilings were observed
comparatively more than the past cases.

6) Seismically isolated buildings: Superstructures of SI buildings suffered almost no
damage. However, damage was observed at the
expansion joints in some buildings. Also, many
cracks in lead dampers and peeling off of paint ofU-shape steel dampers were found.

4.
DAMAGETO
BUILDINGSIN
INUNDATION AREAS DUE TO TSUNAMI

obtain basic data and information required toevaluate mechanisms for causing damage to thebuildings and to contribute to tsunami load andtsunami-resistant designs for buildings such as
tsunami evacuation buildings, by means ofcollecting building damage cases by tsunami,classifying the damage patterns for different

4.1 Purpose of Investigation
The purpose of this investigation is to understandan overview of buildings damaged by tsunami, to36

structural categories, and making a comparison
between the calculated tsunami force acting on
buildings and the strength of the buildings.

These buildings have a column-to-beam frame.
The first floor has a relatively small number ofwalls, but many concrete block walls are placedon the second floor. The first and second floorsof the building in Photo 4.1 are used as shop anddwelling, respectively. The relevant buildings are
estimated to have structural characteristics of low
strength and stiffness on the first floor. As an
opening on the second floor is not large, it isassumed that the second floor suffered a large
tsunami wave pressure and the shear force acting
on the first floor exceeded the lateral loadbearing capacity, resulting in the collapse of thebuilding. Story collapse of the first floor has notbeen observed in 3-story or higher buildings in
the past investigations. In 3-story buildings, ingeneral, reinforced concrete walls are often used
for the first floor. For this reason, the strength of
the first floor is considered to have been larger.

The NILIM and BRI jointly created a tsunami
damage investigation team4 that consists of 27
members. The joint team collected national andinternational standards and codes concerning
tsunami evacuation buildings and tsunami loads
and surveyed about 100 buildings and structuresin three site investigations.
4.2 Summary of Damage in Inundation Area Due
to Tsunami
Table 4.1 gathered up the damage statistics ofmain cities, towns and villages, 49 local
governments in six prefectures, in the tsunami
inundation area based on a survey by Fire andDisaster Management Agency (FDMA) on
August 11, 2011 [4.1]. As for the dwelling housedamage, about 106,000 houses were completely
destructed or missing, about 100,000 houses
were partially damaged, about 106,000 houses
were below partially damaged, and totally about
370,000 houses were damaged and 160 fires
occurred in this area. Each number of complete
destruction or missing of houses of Ishinomaki
or Sendai City in Miyagi Prefecture is more than
19,000. That of Kesen-numa City in Miyagi
Prefecture is more than 8,500. Those ofHigashimatsushima City in Miyagi Prefectureand Minamisoma City in Fukushima Prefecture
are more than 4,500. Those of Miyako City,
Kamaishi City, Rikuzentakata City in Iwate
Prefecture and Minamisanriku Town in Miyagi
Prefecture are more than 3,000. There are areas
which suffered serious damage in Iwate, Miyagi
and Fukushima Prefectures.

Photo 4.1 Story Collapse of 2-story Reinforced
Concrete Building

4 Damage Investigation Team (The members’ positions as

4.3 Classification of Damage Patternsof April 20, 2011) - National Institute for Land andInfrastructure Management, Ministry of Land,
Infrastructure and Transport (8 members): Isao Nishiyama,
Akiyoshi Mukai, Ichiro Minato, Atsuo Fukai, Shuichi
Takeya, Hitomitsu Kikitsu, Hiroshi Arai, and Tomohiko
Sakata; Building Research Institute (19 members): Juntaro
Tsuru, Nobuo Furukawa, Masanori Iiba, Shoichi Ando,
Wataru Gojo, Hiroshi Fukuyama, Yasuo Okuda, Taiki
Saito, Bun-ichiro Shibazaki, Koichi Morita, Hiroto Kato,
Tsutomu Hirade, Takashi Hasegawa, Tadashi Ishihara,
Norimitsu Ishii, Yushiro Fujii, Haruhiko Suwada, Yasuhiro
Araki, and Toshikazu Kabeyasawa

4.3.1 Reinforced concrete buildings(1) Collapse of first floor
A case where column capitals and bases on thefirst floor in a building were subject to flexural
failure and subsequently to story collapse wasseen in two-story buildings (Photo 4.1).

37

Table 4.1 Damage Statistics in Inundation Areas due to Tsunami *Human Damage
Prefecture

City, Town, Village

Hachinohe
Hashikami
Total

AomoriHirono
Kuji
Noda
Hudai
Tanohata
MiyakoYamadaOtsuchi
Kamaishi
OfunatoRikuzentakata
Total

Iwate

Kesen-numa
Minamisanriku
Onagawa
Isinomaki
Higashimatsushima
Matsushima
Rifu
Shiogama
Shichigahama
TagajoMiyagiSendaiNatori
IwanumaWatari
Yamamoto
Total

Fukushima

Ibaraki

Chiba

ShinchiSoma
Minamisoma
Namie
FutabaOkuma
TomiokaNarahaHironoIwaki
Total
Kitaibaraki
Takahagi
HitachiTokai
Hitachinaka
Oarai
HokotaKajimaKamisuTotal
ChoshiAsahi
Total

Sum Total

Dead

Missing

1
0
1
0
2
38
0
14
420
597
796
881
331
1,546
4,625
1,004
550
535
3,153
1,044
2
1
20
66
188
704
911
183
256
670
9,287
107
454
633
141
29
73
19
11
2
308
1,777
5
1
4
2
1

House Damage
Injury10102Complete
Destruction
or Missing

1
19
124
256
653
299
118
569
2,041
410
437
414
890
104
0
1
1
6
3

17
0
17
0
8
17
1
8
33
Unknown
Unknown
Unknown
Unknown
Unknown
67
Unknown
Unknown2
Unknown
Unknown
37
1
10
Unknown
Unknown

3,159
20,720
8,533
3,167
2,939
19,065
4,589
213
59
682
729
1,662

33

2,276

82 Unknown
1
293
5
44
23
90
2,410
2,753
3
3
5
71
38
59
43
6
1
1
6
2
5
1
39
4
144
143
1
188
19
166
5
27
6
15

1
14

1

13
13

2
2

6
432
19
12
31

15,717

4,599

3,443

Below
PartialDamagePartialDamage

250
12
262
10
65
309

769
8
777
16
210
169

225
3,669
2,789

45
1,006
395
3,677

4
176
120

535
182
2,558
2,313
144
337
3,354
4,672
1,321
508
2,784
460
2,993

120
Unknown
27
452
3,248
Unknown
640
10,199
2,471
1,184
1,732
3,973
1,067
5,097

19,922

41,34456,347

39

2,786
720
2,459
2,200
69,725
548
1,049
4,682

922
1,545
1,032
1,042
64,771
Unknown
643
975

8,060
2,403
1,985
1,086
99,492

12
1
3
2
124

58
30

5

3,188
3,629

2
1
1
5

2

1

6
2
2
2
13
8
5
5
23
1
2
8
15

3,092

50
Unknouwn
6,585
13,002
339
131
403
56
79
10
96
368
139
1,621
23
336
359

Unknown
18,931
20,554
1,569
728
3,016
104
720
268
524
1,726
1,660
10,315
105
931
1,036

21,80024,892
5,745
3,213
11,229
3,150
5,863
1,087
4,863
2,567
3,011
40,728
1,938
2,358
4,296

105,689

100,011

169,861* Fire and Disaster Management Agency (FDMA) on August 11, 2011 [4.1]

38

Fire

3
3
3
4
2
1
3
4
3
20

0
162

(2) Overturning(3) Movement and washed away

Overturning was observed in 4-story or lower
buildings. In all overturned buildings, themaximum inundation depth exceeded theirheight. Overturning types include building that
felt sidelong (Photo 4.2) and buildings thatturned upside down. Most of the overturnedbuildings are of mat foundation. In someoverturned buildings on pile foundation, piles
were pulled out.

Most of the overturned buildings were moved
from their original positions. It is estimated thatlarge buoyancy acted on the buildings. Movedand overturned buildings left no dragged traceson the ground. One of the buildings climbed overa concrete block fence on an adjoining land(about 2 m) without destroying the fence (Photo4.3). The building seems to have floated up by
buoyancy. Some of the 2-story apartment houses
with the same shape that were overturned were
washed away and missing. A buoyancy and large
horizontal force seem to have acted on thesebuildings.

Photo 4.2 Overturning of 3-story Reinforced
Concrete Building
An overturning case was often seen in 4-story or
lower buildings with relatively small size of
openings. However, there were many cases
where 4-story or lower buildings with large sizeof openings were not overturned. Consequently,
a size of an opening on an exterior wall is
considered to have greatly affected overturning.

Photo 4.3 2-story Reinforced Concrete Buildingthat Climbed over the Fence and Overturned(4) Tilting by scouring
When tsunami acted on a building, a strong
stream was generated around the corner of thebuilding, resulting in many large holes on the
ground that were bored by scouring. In one case,a building on mat foundation fell into a holebored by scouring (Photo 4.4).

In some cases, there were tsunami traces at theheights of the upper end of openings on the top
floor inside the buildings whose heights were
exceeded by maximum inundation depths. It isconsidered that air has accumulated in the space
between the ceiling and the upper end.
Overturning is considered to occur when an
overturning moment by tsunami wave force
exceeds an overturning strength by a dead loadof a building (considering the effect of buoyancy
as required). A building, in which a distance fromthe upper end of an opening on each floor to aceiling is long, may be overturned even by aslight horizontal tsunami force when buoyancy
significantly acts on the building.

Photo 4.4 2-story Reinforced Concrete Buildingthat was Tilted by Scouring39

(5) Fracture of wall (fracture of opening)case, a multi-story wall in an apartment house
was probably bored by debris impact (Photo 4.6).

When tsunami acts on openings in a building andopposite openings are smaller than the affected
openings, a stream flowing from the affected
openings concentrate on the opposite small
openings. In one observed case related to thisevent, a stream generated by tsunami provided alarge pressure to a reinforced concrete nonstructural wall around small opposite openings.
The pressure enlarged the concrete wall to theoutside and fractured the wall reinforcement. A
tsunami wave force that acts on a building will
be reduced if the size of opening affected by theforce becomes larger. The same trend isconsidered to apply to an outlet surface of thestream.

Photo 4.6 Wall Opening Generated by Debris
Impact4.3.2 Steel buildings

A case where such wall reinforcement was
fractured is often seen in wall members withsingle layer bar arrangement. In one damagedbuilding (Photo 4.5), a 300 mm-thick shear wallwith double layer bar arrangement and a support
span of more than 10 m and without no 2-story
floor was bent inside by a tsunami wave pressure.
However, a shear wall in an area (Photo 4.5 Backof the building), where there is a floor on thesecond story and a support span is not long in thesame building, was not bent.

(1) Movement and washed away by fracture of
exposed column base
A typical case of building movement and washedaway is that a building moved and flew due tothe fracture of anchor bolts and/or base plates atsteel exposed column bases and the fracture of aweld between the column and the base plate(Photo 4.7). In most cases, a foundation andsome column bases were left in a site, but the
body of a building was moved beyond the siteand missing.

Photo 4.5 Out-of-plane Fracture of Reinforced
Concrete Shear Wall without Floor
Photo 4.7 Steel Building Overturned by Fractureof Column Base Anchor Bolts(6) Debris impact
Debris impact was seen in most of the nonstructural members such as window and ceilingmaterials. The number of cases of clear damage
to skeletons was not large, but in one observed(2) Movement and washed away by fracture ofcapital connection
In damage cases relatively often seen a column

40top connection on the first or second floor in abuilding was fractured and the building was
moved and washed away. When a column basehas a large strength like concrete encases type orembedded type, this type of fracture isconsidered to occur. In one case (Photo 4.8), a
foundation in a building, and several columns on
the first floor (or up to the second floor) were left
on a site, and the columns fell in the same
direction (Photo 4.8).
In most cases, welds between diaphragms withlower flanges and the first-floor columns werefractured and the sections of the columns were
exposed. In one building, flanges of the secondfloor H-shaped beams were torn. Based on the
deformation states near the column bases, it isestimated that a tensile force acted on the firstfloor columns and fractured the first-floor
column top connections after the first floor was
greatly tilted to the same extent as the inclinationof the remaining columns.

Photo 4.9 Overturning of 3-story Steel Building(4) Collapse
Damage cases of skeleton collapse include story
collapse of the first floor in a 2-story steelbuilding (Photo 4.10) and partial collapse of awarehouse on the coast.

Photo 4.10 Story Collapse of First Floor in 2story Steel Building
Photo 4.8 First-floor Columns Falling in theSame Direction(5) Large residual deformation
Slight tilting was often observed in steelbuildings with only a skeleton left. In one case
(Photo 4.11), a gabled roof frame building did
not collapsed despite large residual deformation.

(3) Overturning
One case, in which a whole building including
foundation is overturned, was confirmed. Mostof the ALC panels of claddings were left (Photo
4.9).

41

related to a maximum inundation depth. In thecase of a maximum inundation depth more thanabout 6 m (equivalent to a height of eaves of 2story wood house), the number of 1-story and 2story Wood houses that remained was almost
zero. A damage pattern case where asuperstructure in a house was washed away with
only its foundation and ground sill left (Photo4.13) or where the superstructure and the groundsill were washed away with only the foundation
left was frequently confirmed.
Photo 4.11 Tilted Gabled Roof Frame(6) Full fracture and washed away of cladding
and internal finishing materials
Cladding materials such as ALC panel were
almost fully fractured and washed away, and asteel frame as a skeleton was left. This case wasoften seen (Photo 4.12). It is considered that an
external force that acts on the skeleton became
small, due to early washed away of the cladding
materials. In the remaining building, slight tiltingof the skeleton, member deformation on the faceaffected by tsunami, or members locallydamaged possibly by debris impact, wasobserved.

Photo 4.13 Remaining Ground Sill after Washoutof Superstructure
In the case of a maximum inundation depth ofabout 1 m, most of wood houses remained. Somewood houses were damaged possibly due todebris impact. In the case of a maximum
inundation depth of about 1 to 6 m, some woodhouses remained. Some wood houses behind therelatively stronger building for tsunami wave
force such as a reinforced concrete building
remained. This is possibly due to that a tsunami
wave force was significantly alleviated by thebuilding not washed away (Photo 4.14).

Photo 4.12 Remaining 3-story Steel Building
In another damage case, openings on the faceaffected by tsunami and on its opposite face, ortransverse faces were greatly damaged andfractured possibly due to stream runoff.
GSI
Photo 4.14 Remaining Wood Houses Behind
Remaining Building

4.3.3 Damage to wood houses
Damage patterns of wood houses that werecaused by tsunami are considered to be greatly42

In addition to these cases, a tsunami wave force
was reduced possibly due to many openings in
the direction affected by tsunami, or a wooden
house remained despite washed away of columns
and external walls in the corner of the building.
Several houses that have a reinforced concretepiloti on the first floor, or a mixture of wooden
and reinforced concrete structures, remained(Photo 4.15).

The Cabinet Office made guidelines for tsunami
evacuation buildings in 2005 [4.3]. After the
Tohoku earthquake, the committee on structuraldesign for tsunami evacuation buildings (Leader:Prof. Y. Nakano, University of Tokyo) was
organized in order to validate the equation oftsunami wave pressure on buildings, using thedatabase for 52 buildings and 44 structures
investigated in inundation areas due to thetsunami.
The NILIM announced the results of thevalidation of the equation of tsunami wave
pressure on buildings based on the interim
committee report in August, 2011 [4.3]. The
general content of the interim result is as follows.

Equation of Tsunami
Wave Pressure

3h

Buildings

Photo 4.15 Remaining Mixed Building withReinforced Concrete Piloti on First FloorhzDesign inundation depth

3ρgh

Equation of Tsunami Wave Pressure: qx=ρ g (3h-z)

4.4 Database for Investigated Buildings(1)

qx: design tsunami wave pressure ( kN/m2)
ρ： density of water (t/m 3)
g： gravitational acceleration (m/s 2)
h： design inundation depth (m)z： height from the ground (0≦z ≦ 3h) (m)Outer dimensions of about 100 buildings anddimensions of their skeletons were measured in
the site investigation. Maximum inundation
depths were measured from tsunami traces on
surveyed buildings and surrounding buildings.
These measurement results were integrated into a
database for investigated buildings. Building
name, address, purpose, construction year,
designation as tsunami evacuation building,
structure category, number of stories, outerdimension, distance from seacoast (river), GPS
position, altitude, surrounding circumstances,damage situations, etc., were included in the
database. In addition, photos of investigatedbuildings that were taken from four directions
where possible were attached to the database.
Based on the database, we estimated strengths ofthe buildings and tsunami loads on them, and are
evaluating whether the estimated values are
consistent with the damage situations.

In the Cabinet Office guidelines, the design
tsunami load for the tsunami evacuationbuildings was adopted as the tsunami wave
pressure eq. (1), hydrostatic pressure of 3 times
design inundation depth, based on the maximum
envelope of the experimental result in Japanbecause of the following reasons:

4.5 Discussion on Guidelines for Tsunami
Evacuation Buildings by the Cabinet Office ofJapan

The strength of reinforced concrete buildings andstructures was calculated from the database to beconverted into the depth of the hydrostatic

Fig. 4.1 Design Inundation Depth and Tsunami
Wave Pressure of Guidelines for Tsunami
Evacuation Buildings (The Cabinet Office) [4.2]1) Simple equation of the design tsunami load2) Safer estimation for the design tsunami load
including hydrodynamic effects
3) Lack of effective data for the design tsunami
load

43

pressure equivalent to the strength of thebuildings and structures under the following
conditions.

4) Tsunami load is simply reduced in proportion
to a ratio of openings to total elevation area
affected by tsunami.

Measured inundation depth ηm(m)

A depth ratio

is defined as eq. (2).
(2)

: depth ratio: depth of the hydrostatic pressure equivalent
to the strength of the buildings and structures (m): measured inundation depth (m)○ No damaged structures△ Inclined structures
× Collapsed structures◇ Survived buildings＊ Collapsed buildings

Fig. 4.2 plots damage situations of buildings andstructures with some obstacles for tsunami effectforand. A boundary of damage situationsof buildings and structures can be considered at
the depth ratio =1 except *1 and *2 in Fig. 4.2
when the inundation depth was measured lessthan about 10m. Many buildings at the depth
ratiomuch less than 1 remain when theinundation depth was measured more than 10m.

Depth ratio a

Fig. 4.2 Depth Ratio of Investigated Buildings
with Some Obstacles for Tsunami Effect [4.3]*1: structures paralleled to the tsunami direction*2: large openings in side faces of a buildingThis section classified the damage patterns fordifferent structural categories and briefly
discussed the factors that had caused various
types of damage. Based on the results of therelevant investigation, we are now conducting an
additional field investigation as required andcollecting design documents for damagedbuildings, while further evaluating the effects ofbuilding openings and buoyancy and proceedingwith the elucidation of mechanisms for causing
damage and the identification of tsunami loads
on buildings.

1) Mass per unit area for reinforced concretebuilding structures is 14 (kN/m2).
2) Compressive strength of a concrete is 21(N/mm2) and yielding stress of a round bar is294 (N/mm2).
3) Lateral load carrying capacity of reinforced
concrete building structures is roughly
estimated with total section area and average
ultimate shear stress of columns (σ=1
N/mm2) and structural walls (σ=3 N/mm2)
according to the Japanese seismic evaluationof existing reinforced concrete building
structures.

5.
ACTIVITIESONDEVELOPING
COUNTERMEASURES FOR MINIMIZINGTHE EFFECT OF THE LONG-PERIODGROUNDMOTIONSTO
BUILDING
STRUCTURES

the 2003 Tokachi-Oki earthquake. The longperiod motions caused by the large magnitude
earthquake and enlarged by the deep sedimentarybasin structures under the Tomakomai region
amplified and elongated the motions acting to thetanks and the excessive sloshing of the liquidsurface occurred and the liquid (oil) overflowed
the tanks and the liquid was ignitioned fire.

5.1 Background of the Study
A large scale of fire had broken out to the large
oil storage tanks in Tomakomai, Hokkaido after

After this earthquake, the long-period motions

44

featured with slow, cyclic and long duration
recalled the concerns on the future large
earthquakes to occur in the Pacific coast of Japangenerating such long-period motions and theexcessive responses to long-period building
structures such as super high-rise and seismicallyisolated (SI) buildings.

building codes and one of them was thedevelopment of the design long-period
earthquake motions. Under this funding, theselected working team and the BRI have been
doing the cooperative study on the long-period
motions. Various kinds of assistance were given
from experts on strong ground motion andstructural engineers.

Meanwhile, large earthquakes such as Nankai,
Tonankai and Tokai earthquakes are supposed tooccur on subduction zones around Japan in near
future. Therefore, we have serious concerns on
structural damage due to the long-period groundmotions generated by those large earthquakes.

The cooperative study had continued from fiscal
years 2008 to 2010 and a research report was
published by the BRI as product of thestudies.[5.4]Based on the study, the NILIM prepared atentative new proposal of some methodology toevaluate the long-period motions for new andexisting high-rise buildings in December 2010
and invited the public comments from the MLIT
(Tentative New Proposal by MLIT and NILIM).

The Central Disaster Management Council, theCabinet Office, had set up many committees on
establishing countermeasures for respective large
influential earthquakes. They had also started thestudy on the effect of the long-period earthquake
motions for several subduction-zone earthquakes
and estimated the ground motions andsubsequent damage for urbanized areas inJapan.[5.1]

These are the recent progress on the evaluationof long-period motions. Here, we would like tobriefly show the project for developing thecountermeasures for minimizing the effect of thelong-period motions that MLIT and NILIM
proposed.

The Headquarters for Earthquake Research
Promotion (HERP) established in the Ministry of
Education, Culture, Sports, Science andTechnology (MEXT) after 1995 Kobe earthquake
had also started the study on the hazard maps
showing the long-period motion estimates thatare based on the simulations with possible
earthquake source rupture process based on
experience during the past large earthquakes andthe estimated underground structures. The
preliminary maps for the Tonankai, Tokai and
Miyagi-Ken-Oki earthquakes were publicized in
September, 2009. [5.2] Preparation of theadditional long-period motion maps on someother subduction-zone earthquakes are now inprogress for publication by the HERP.

5.2 Brief History of Design Earthquake Motionsfor Super High-rise Buildings in Japan
In Japan, the construction of high-rise buildings
over 60 meters (hereafter, referred to as HRbuilding) started in the late 60’s. The recorded
motions available for design at the time werevery few both in number and quality. Therefore,
an amplitude-magnified recorded motions weremainly used as well as the well-known records
such as El Centro NS component from 1940
Imperial Valley earthquake or Taft EW
component from 1952 Kern County earthquakethat were already in use. The maximum
amplitude levels used for magnification were200-300 cm/s2 for elastic design, and 300500cm/s2 for elastic-plastic design. Afterwards,
the scaling with maximum velocity amplitudelevel was replaced as appropriate for relatively
longer-period dominant ground motions. The
scaling with maximum velocity amplitude with
25cm/s for damage-protection design and 50cm/s

The Architectural Institute of Japan (AIJ) had
also conducted the extensive study on safetymeasures for building structures against the longperiod earthquake motions. [5.3]
Under these various study activities including
those currently in progress as background, the
MLIT and the NILIM initiated the funding [1.4]
to maintain and promote the enhancement of the45

for collapse-protection was established in mid
80’s. [5.5] The scaling scheme is still maintainedfor parts of the design motions. In mid-90’s, aproject left a fruit that proposed a design motions
for the HR buildings. The project was conducted
as a cooperative research work between the
Building Center (BCJ) of Japan and the BRI of100

h=0.05

8
6

4

4

2

10

Engineering Bedrock

BCJ L2BSL E.B.
BSL Soil 1
BSL Soil 2
BSL Soil 3

Acceleratio (m/s)

Pseudo Velocity (cm/s)

2

Japan. In the proposal, the design motion was
defined at the outcropped hard soil surface thatwas referred to as ‘Engineering Bedrock’. This
motion is named as BCJ-wave. The pseudo
velocity response spectrum is shown in Fig. 5.1.
[5.6]

8
6
4

2
0
-2
-4

2
5 6 7

0.1

2

3

4 5 6712

3

4 5 6 70

10Period (s)

20

40

60
time (s)

80

100

120

Fig. 5.1 BCJ (L2) and Building Standard Law Design Spectra and Building Standard Law Wave forEngineering Bedrock

The Building Standard Law of Japan was partly
revised in 2000, consequently, the design
spectrum for response history analysis wasofficially added as one of its notifications. The
design spectrum was derived corresponding to
the conventional design seismic force and was
lower than the previously shown BCJ-wave
spectrum as also shown in Fig. 5.1. In Fig. 5.1,
an example of notification-spectrum compatible
waveform is shown. The notification also
requests site-specific motions referred to as ‘sitewave’ considering the earthquake environment of
the construction site such as nearby influential
active fault, etc. (CAO, 2008 [5.1], AIJ, 2007[5.2], etc.)

cities in Japan. Most of those are located onlarge deep sedimentary basins.
(4) Recorded long-period motions are stillinsufficient including building responses
although the nationwide seismometer
networks have been established after the
1995 Kobe earthquake.
(5) Urgently
neededistheevaluation
methodology of ground motions with large
earthquakes expected to occur in near future
for confirming the safety of many existingand new structures.

The problems are summarized as follows;(1) The longer-natural period buildings such as
high-rise and seismically isolated buildingsthat have been thought as advantageous tostrong earthquake motions turned to bevulnerable to long-period motions.
(2) The long duration time is important forbuildings with low-damping and/or equippedwith cumulative energy dissipation devices.
(3) Many such buildings have been built on large

The research on the evaluation of long-period
motions has widely been conducted using
theoretical method such as the 3D-FDM. On theother hand, the researches with the empiricalevaluation of the long-period motions are very
few to date. Kataoka (2008) [5.7] showed theattenuation formula for evaluating the response
spectral properties. However, almost no research
work has targeted on the time history generation.

5.3 New Methodology for Design Long-period
Ground Motions46

Considering the usefulness of the formula andexpecting the data accumulation in future, theempirical method will become much more usefulin engineering sense. In addition, the evaluatedmotion with the empirical method will be usefulenough to judge the plausibility of the theoreticalmethod.
Here, we used nationwide many ground motion
records to make an empirical model to predictthe ground motion with 0.1 to 10 second period
range. Furthermore, based on this formula, weinvestigated the method to construct the longperiod ground motion time histories generated byhypothetical large future earthquakes. [5.8].
5.3.1 Attenuation formula for acceleration
response spectra with 5% damping in longer
periodFig. 5.2 Location of Earthquake Epicenters Used
2

Amplification

The data used here are selected from JMA87,
JMA95, K-NET, and KiK-net, etc.
The selecting criteria of records are as follows,
1) Subduction Type :Mj>6.5 for hypocentral
distance<400km (Mj:JMA magnitude)2) Crustal Type: Mj>6.0 for hypocentral
distance<350km
3) Hypocentral depth<60km

10
6
5
4
3

AIC003
AIC004
OSKH02

2

1
2

4

6

8

10

Period (s)Fig. 5.3 Amplification Factors cj(T) of OSKH02
in Osaka, AIC003 and AIC004 in Aichi

The location of earthquake epicenters and theirmagnitudes are shown in Fig. 5.2. It is seen thatthe subduction type earthquakes are mainly on
the Pacific Ocean side.

In the least square analysis, the 5% damping acc.
response spectra is related with the moment
magnitude and the shortest distance fromrecording station to the assumed source area of
each recorded event, i.e.,log10 Sa (T )  a (T ) M w  b(T ) R log10 ( R p (T )  d (T )100.5 M )  c(T )  c j (T )w

where, Mw is the moment magnitude and R is theshortest distance in kilometer from the recordingsite to the source area, and a(T), b(T), d(T), p(T),c(T), cj(T) are coefficients to be determined withthe least squares analysis. The coefficient c(T) is
assumed to be the site amplification factor for
KiK-net FKSH19 station which is regarded as

47

benchmark station on the seismic bedrock andcj(T) is a site amplification factor for the j-th
recoding station. The least square analysis was
conducted separately for subduction and crustal
earthquake type datasets. However, the final
cj(T) was taken as a weighted average of cj(T)coefficients for both cases with data number
taken as weight. Therefore, the cj(T) is treated as
identical for subduction and crustal earthquakes.
Fig. 5.3 shows the site amplification factors forthree sites, OSKH02, AIC003, and AIC004. It isseen that the site amplification factor that shows
the amplification from seismic bedrock tosurface becomes nearly 20 at around 6 second for
OSKH02 site, located at the coast of the Osaka
Bay. The sites AIC003 and AIC004 are both in
the Aichi Prefecture, but it is seen that the site
amplification factors are different within the
Nobi plain. In addition, the site amplification
map for whole Japan area is also shown in Fig.
5.4. It is seen that the factor takes large value forarea such as Kanto, Osaka, Nobi, Niigata, Sakata,
Ishikari-Yufutsu, and Tokachi plains that holds
thick overlying soil medium.

Fig. 5.4 Nationwide Distribution of Amplification Factors cj(T) with Periods of 3, 5, and 7 Second
5.3.2 Empirical formula for frequency-dependent
average and variance of narrow-band groupdelay time

spectral non-stationarity of the wave seemingly
caused by the dispersion of surface waves. The
average values are corrected so that the rupture
initiation time should be zero.

The average value  tgr of the group delay timecorresponds to the gravity center of arriving timeof wave group in a narrowband. The standard
deviation  tgr of the group delay timecorresponds to the scatter of the arriving timethat is the duration time of the wave group in the
narrowband. [5.9] Since the group delay time isthe first derivative of the Fourier phase spectra,
once the initial phase angle is fixed, the otherphase angles are calculated recursively, assuming
a normal distribution with the average andstandard deviation values within the narrowband.
The method holds an advantage to realize theSince both of the average group delay time  tgr ,and the standard deviation  tgr of group delay
time can be related with the source property, patheffect and the site characteristic, both  tgr and tgr were eventually related in the following
2

relationship.

Y ( f )  A( f ) M 01/3  B ( f ) X  C j ( f )48

where, Y(f) is either  tgr or  tgr 2 , M0 is seismic

 tgr with horizontal component for OSKH02,

moment in dyne-cm, X is the hypo-central
distance in kilometer, the ‘f’ is frequency in Hz.
A(f), B(f) and Cj(f) are determined by the leastsquare analysis. The site coefficient for  tgr and

AIC003, AIC004 sites are shown in Fig. 5.5. It isseen from the figure, both site coefficients
become larger for longer period.

2

Fig. 5.5 Site Coefficient with Average (left) and Standard Deviation (right) of Group Delay Time

観測波形(NS 成分)

SA(5%)とtgr とtgr=平均

Fig. 5.6. Comparison of pSv and Waveform between Recorded and Simulated Motions for OSKH02

5.3.3 Generation of waves with empiricalformulaAt first, the method was examined with its
validity by simulating the recorded motions
during the 2004 Off-Kii-Peninsula earthquake(Mw=7.4). Fig. 5.6 shows the comparison of
response spectra and waveform between
recorded and generated waves for the 2004
earthquake for the OSKH02 site. The duration
time of generated velocity waveform is less than
the recorded, when the average values with thegroup delay time standard deviation is used.
These comparison shows the method canreproduce the recorded motion when a regression
error is taken into account appropriately.

For generation of the time history, the Fourierphase angles are firstly determined using theregression formula with tgr and  tgr andgiving initial phase angles and random numberswith normal distribution of  tgr and  tgr . Then,the 5% damping acc. response spectrum aredetermined with the attenuation formula. The
Fourier amplitudes will be corrected so that thegenerated wave holds the acc. Response
spectrum by correcting the Fourier amplitudes
cyclically. [5.10]

We generated the waves for Nankai (Mw=8.5)

49

earthquake with site OSKH02, and for TokaiTonankai (Mw=8.3) earthquake with sites
AIC003 and AIC004 sites. The macroscopic fault
plain modeled as a rectangle for Nankai
earthquake [5.11] and the rupture initiation
points and the location of the predicting site areindicated in Fig. 5.7(a). In Fig. 5.7(b), therectangular fault plain model for Tokai-Tonankai
earthquake based on Sato, et. al. (2006) [5.12]
etc. are shown. When the multiple plain fault
model is assumed, each generated wave fromsingle component fault model will be added
considering rupture time differences to get the
final total waveform.

速度波形：乱数 1

速度波形：乱数 2

加速度波形：乱数 1

Fig. 5.9. Velocity (two random number cases)
and Acceleration Waveforms with OSKH02 Site
for Hypothetical Nankai Earthquake

The pseudo response spectra for the Nankai
earthquake using the method was shown in Fig.
5.8, and compared with the preceding
simulations by Kamae (2006) [5.13], Tsurugi(2005) and Sekiguchi (2006) [5.14]. Kamae’s
result includes components longer than 2.5
second. Other simulations include short period
components. The generated velocity waveforms
are also shown in Fig. 5.9.

Fig. 5.10 Comparison of pSv’s for TonankaiTokai Earthquake between Previous Study (left)
with NST site at downtown Nagoya and thisstudy (right) with AIC003 and AIC004 sites

Mw8.0
Mw8.2
Mw8.2

km

Mw8.4

In addition, the pseudo velocity response spectra
for AIC003 and AIC004 for Tonankai-Tokai
earthquake were compared in Fig. 5.10 with thesimulated wave for NST site, located at
downtown Nagoya that was estimated with socalled hybrid procedure. It is seen that the
spectral levels at longer period for AIC004 andNST are comparable. In Fig. 5.11, the predictedwaveforms for both sites are also compared. The
maximum velocity amplitudes and the effective
duration times for both waves are almost
equivalent.

(a) Nankai Eq.
(b) Tonankai-Tokai Eq.
★ First rupture, ☆ Second rupture

Fig. 5.7 Source Models used for Nankai and
Tonankai-Tokai Earthquakes (Tsurugi, 2005,
Sato, 2006)h=5%(a) 既往の予測波(b) 本研究の予測波
Fig. 5.8
Comparison of pSv with
Other Research
Results (left) and This Study (right)

50

Fig.5.11 Selected areas from Tokyo, Aichi and Osaka and those area was divided into 9 sub-divided areas.
Each sub-area is given design spectrum and corresponding time history to represent the sub-area.

Fig.5.12 Assigned long-period motion for area No.2 in Tokyo corresponding to the pink area for therightmost map in Fig. 5.11. The acceleration and velocity waveforms are given above. The 5% damping
pseudo response spectrum and the 10% damping energy spectrum are given in the lower figure.

5.4 Tentative New Proposal for Countermeasures
on Long-period Earthquake Motions by MLIT
and NILIM

motions for HRs in early days do not necessarily
meet the standards of today, since there were notthe concept of the design long-period motion atthat time. Therefore, these buildings need to beverified their safety with the newly evaluateddesign motions.

Based on the studies introduced in the preceding
sections, the MLIT and the NILIM have made aso-called tentative new proposal on the
countermeasures of seismic safety for high-risebuildings in December, 2010. This section briefly
describes about it.

5.4.1 Earthquakes, evaluation of long-period
motions, and zonings
The Tonankai, the Tokai and the Miyagi-KenOki earthquakes were selected for the evaluationof the long-period motions. The earthquake
magnitudes and epicenters for these three

As explained in 5.2, the design earthquake
motions for high-rise buildings in Japan havebeen changing to date. Therefore, the design

51earthquakes were based on the HERP’s
specification, with which they also made longperiod motion maps.

assigned one even partly exceeds the used one,the building is requested for re-evaluation of theseismic safety with the newly assigned longperiod motions and for strengthening if necessary.

The highly urbanized area in Tokyo, Aichi, andOsaka was selected and made 9 zonings weremade that represent the surrounding area in viewof the long-period motions as shown in Fig.5.11.
The Tokyo Metropolitan area has 4 zonings that
represent Tokyo Bay, Tokyo uptown, Yokohama
and Chiba sub-areas. The Aichi area wasrepresented by three zonings, the western, thecentral and the eastern sub-areas. Finally, theOsaka area was represented by two zonings, bothfacing on the Osaka Bay also shown in Fig. 5.11.
Depending on the sub-area that each of theconstruction sites belongs, a long-period motion
is assigned for the safety check. For example,
area-2 in Tokyo (red area) is given the motion
given in Fig. 5.12.

5.4.3 The MLIT/NILIM proposals and re-start ofthe study
The MLIT/NILIM proposal immediately invitedthe public comments on December 21st until theend of February, 2011. Many comments werecollected. The brief summary of the comments
are disclosed by the MLIT. It says,
1. Agrees with the MLIT/NILIM actions for the
long-period ground motions
2. Some other earthquakes that control the areasuch as the Nankai earthquake should beconsidered.
3. Some alleviated countermeasure or financial
assistance will be recommended, because theretroactive application is too strict.
4. The design criteria in building performance
should be presented as well as the input
motions.

The 9 zonings are made specifically for the threeearthquakes.
For earthquakes other than these, the proposal
includes how to generate the long-period motions
for the specific site.

It is taken into consideration that these aresummarized comments collected before the
Tohoku earthquake occurred.

5.4.2 Application of the tentative new proposals
by the MLIT and the NILIM

In addition, huge number of strong motion
records is obtained by many public and private
earthquake
observation
networks.
Someverification study will be crucial using these data
to enhance the reliability of the methodology that
can account for the recorded data.

For new high-rise buildings, re-evaluation ofearthquake safety is requested using the assigned
long-period motion from aforementioned threelarge earthquakes.
Some consideration is requested for protecting
the furniture and utensils, such as copy machinesfrom overturning.

5.5 Conclusions

Some technical information for the promotion
with affordable design consideration will be
provided, for excess long-period motions withmultiple earthquake source events as well as the
motions from single event mentioned above,

In this paper, a method was proposed that would
produce broadband long-period (0.1-10 sec.)
earthquake motion waveforms using earthquake
parameters, such as, the seismic moment, themacroscopic fault plain model, rupture initiation
position, time difference among ruptures for
multiple events.

For existing high-rise or seismically isolatedbuildings that already acquired the minister’s
approval, the assigned motion is compared withthe actually used design motions and if theIt was suggested that the empirical formula forlong-period earthquake motions even in spectral
property was very few, however, the method
presented here will be useful in case of52

generating earthquake motion time history.

in parallel on the earthquake responses of the HR
buildings and/or the base-isolated buildings tothese simulated motions and their uncertainties.

The simulated waves using the proposed method
was in general comparable to the results in thepreceding research results, although the numberof the long-period earthquake records are in
general very small and the situation makes thestatistical study using those data unreliable andalso that there are some cases in which therecording time is not sufficient for the purpose.
In view of that these research results will beapplied to the specific field, seismic design ofbuildings, it is necessary to make further studies

In addition, the MLIT/NILIM tentative new
proposal for the countermeasures for the longperiod ground motions was introduced. The
proposal will be upgraded using the new datafrom the Tohoku earthquake.

The Building Structural Code Committee5
chaired by Tetsuo Kubo, University of Tokyo,
established in NILIM will investigate theseissues as shown in Fig. 6.1. Where, MLIT and
NILIM identify study items and invite those(“execution team”) who serve as volunteer for
the work on study items by utilizing the grant-inaid [1.4] for maintenance and promotion ofbuilding codes. BRI is appointed to work
together with the execution team.

6. COPING ACTIVITIES BY NILIM AND BRI
From the Tohoku earthquake, the following
issues are obtained to be countermeasured
administratively for example by modifying
current building technical standards.
(1) Evaluation of load effect by tsunami(2) Countermeasure for falling down of nonstructural elements, especially of ceilings(3) Long-period earthquake ground motion
countermeasure for buildings with long natural
periods(4) Liquefaction countermeasure for residential
land of detached housings
In addition to above issues, cracks in thedamping devices (lead damper) of theseismically isolated buildings were observed
under a number of reversed cycles of loadings
with small displacement amplitude even at placesof rather small ground motions, with no severe
damage in building structures. Lead rubber
bearing which is made of rubber layers andstiffening plates with lead plug inserted isthought to be investigated like cracked exposed
lead damper. The Japan Society of Seismic
Isolation has started the survey and investigationon this issue on the request by MLIT and NILIM
utilizing the grant-in-aid mentioned later, thus
the progress of the study should be carefully
observed.

5 Draft of the building structural codes prepared by NILIM

will be reviewed from the technical point of view by the
Building Structural Code Committee. The modified draftby NILIM based on the review will be sent and will be
put into Enforcement order or Notification by MLIT.

53

Building Structural Codes Committee
Chaired by Tetsuo Kubo, Tokyo University
Field Survey on the Earthquake on April 21 and 22
First meeting was on June 8, second on August 18
WG on Long-period earthquake
ground motion
First meeting was on July 20
Secretariat for supporting
Committee and WG
ＴＧ on Building Structural Codes andStandards in general
First meeting on July 26

Draft of
Building
Structural
Codes

Public comments on Tentative
Plan of countermeasures forlong-period motion
Collection of information byusing grant-in-aid formaintenance and promotion ofbuilding standards
42.Effect of long-period
motion on super high-risebuildings
21. Needs and seeds
collection

Publiccomments or
proposal ofbuilding
structural
codes fromprivateFig.6.1 Building Structural Codes Committee(1) Outline of evaluation of load effect bytsunamione side of the building whose inundation depth
is 3 times the design tsunami inundation depth.
Here, the value of 3 was determined from thelaboratory test utilizing waterway, which wasvalidated later by the field survey of tsunami
damage by the 2004 Indian Ocean Tsunami
Disaster [6.1]. However, the inundation depth of
this time tsunami reaches about 15m or morewhich is far above the previous study and the
topographical shape of rias coastline has not yet
been verified. According to the interim report by
the execution team, 44 examples of simple
structures and 52 examples of buildings which
subjected tsunami damage were collected andused for verification of the value. Fig. 6.2 shows
the comparison of the measured tsunami
inundation depth and the estimated value forsimple structures and buildings with and/or
without tide embankment etc. As seen from thefigure, the value of 3 seems to be reduced
drastically in case of with tide embankment, andthe value becomes less than 1 in case of higher
tsunami inundation depth such as over 10m. It is
explained in the interim report that the loadMiyagi Prefecture and Ishinomaki City assigned
building restrictions in the damaged urban area
based on the Article 84 of the Building Standard
Law6. This assignment is active for 8 months at
the maximum by the Special Law which cameinto force after the Tohoku earthquake. At thetime of reconstruction of these areas, it is surly
requested to reconstruct safe urban area even foranother tsunami. Therefore, the technicalinformation on the load effect by tsunami, which
can be used in designing new buildings, isurgently in need.
Investigation on the building structural codes in
the area of tsunami danger was started after theearthquake by the execution team of the Instituteof Industrial Science, Tokyo University lead by
Yoshiaki Nakano. The study items are 1)
verification of structural design method fortsunami evacuation building, and 2) building
restrictions, which should be, in the area oftsunami danger. In this section, 1) will be
explained briefly.

6 (Building Restrictions in Afflicted Urban Areas) Article

84. In case of a disaster in an urban area, the special
administrative agency may, if it deems it necessary forthe city planning or the land readjustment work under theLand Readjustment Law, designate areas and restrict or
prohibit the construction of buildings therein, for alimited period of time within one month from the day ofthe occurrence of the disaster.

In the existing guidelines [1.3] on the structuraldesign method for tsunami evacuation buildings,
as shown in Fig. 4.2, the tsunami load isestimated as the hydrostatic pressure acting on

54

Design Inundation Depth (m)effect by tsunami is the largest not at the highest
inundation depth, so the effective tsunami
inundation depth can be reduced in case of highdepth.

stiffness ceilings was send after the 2003
Tokachi-Oki earthquake, and an appropriate
strengthening of clip members which connect
ceilings to hanging bolts was indicated after the2005 Miyagi earthquake. Fig. 6.3 shows
schematically these technical advices. In the
figure, red circle potions should be taken care in
the design of ceilings. From the fiscal year of
2008, vibration measurement, time history
analysis, and vibration test using shaker on
gymnasiums were performed in order to prepare
concrete design manuals for ceilings against
falling down.

Blue marks are notdamaged, and red
marks are damaged.

Structures(a) Modified Value of 3 based on Surveyed Buildings(with Tide Embankment)

Design Inundation Depth (m)Structures

Red marks aredamaged.

Ceiling

BracesClearance between
ceilings

Clearance

Earthquake induced
motionCeiling iscontacting toStructural
Members(b) Modified Value of 3 based on Surveyed Buildings(without Tide Embankment)

Fig.6.2 Comparison of the Measured Tsunami
Inundation Depth and the Estimated Value

Stiffness difference between
ceilings in different levels

In the latter half of this fiscal year, study on thebuoyant force and the pile resistance through thestudy on the overturned buildings, study on theeffect of the openings of the buildings on
tsunami force, and study on the impact force by
the debris to the buildings will be carried out indetail. The report will be planned to besummarized by March, 2012.

Earthquake induced
motionFig.6.3 Schematic Explanation of Technical
Advice on Details of Ceilings
In the Tohoku earthquake, building collapse wasrarely observed but many ceilings falling down
was reported at the places with not large
earthquake motions and even death due to falling
down of ceilings was occurred for example in theImperial Crown Style building in Chiyoda Ward,
Tokyo.

(2) Outline of countermeasure for falling down of
non-structural elements, especially of ceilings
After the 2001 Geiyo earthquake, in which manyceilings fell down in the large space gymnasiums
stood in the urban park, the technical advice tokeep appropriate clearance between ceiling andsurrounding structure and to install braces on
hanging bolts was send from MLIT to the special
administrative agency7. An additional technicaladvice to keep clearance even between different

Therefore, in order to extensively study theceiling falling down including effectivenessstudy on the existing technical advices, the7 The head of a city, town, or village for the area of a city,

town, or village having building officials, or the
prefectural governor for the area of other cities, towns, orvillage.

55

investigation on establishing building structural
codes for non-structural elements based on theearthquake damage was initiated by the
execution team of Building PerformanceStandardization Association. The study items are1) collection and classification of ceilingdamages in the Tohoku earthquake, and 2)
building structural codes, which should be, fornon-structural elements especially for ceilings. In
the interim report, 151 examples of ceilings
falling down are collected through thequestionnaire to the special administrative
agency and field survey was made on theselected 10 examples. Fig. 6.4 summarizes theshape of the damaged ceilings in these buildings.
室

because the motions predicted by HERP justinclude the component of motions with 3.5
seconds or longer and so the higher mode of
response of the buildings cannot be represented.
The result was announced as the tentative new
proposal [1.1] and public comments werecollected. Many comments say that Nankai andcombined Tonankai-Nankai earthquakes should
also be included in the scope of the tentative new
proposal as they affect more on the buildings in
Nagoya and Osaka Areas than those in thecurrent scope.
Meanwhile, the Tohoku earthquake is muchlarger than the prediction by HERP and goodquality strong motion observations became
available. Therefore, the investigation of theeffect of long-period earthquake ground motions
on the buildings with long natural periods isstarted by the execution team of Osaki
Laboratory, Shimizu Cooperation.

室

Building A
Building B

Building C

室
Building E
Building D

Building F

Building G

Building H

Building J (Hall)

Building J (Exhibition Hall)

The study items are 1) validation of prediction
method (tentative new proposal) utilizing new
observation data for long-period earthquake
ground motions, 2) preparation of long-period
earthquake ground motions at principal places
for Nankai and combined Tonankai-Nankai
earthquakes, and 3) earthquake response
calculation of super high-rise buildings by the
prepared motions. In this section, the outline ofthe validation study in 1) will be explained
briefly.

Building I

Fig.6.4 Patterns of Ceilings Surveyed
During the next six months after the interim
report, concrete countermeasure methods forexisting ceilings and safety calculation methods
for new ceilings will be considered.
(3) Outline of long-period earthquake groundmotion countermeasure for buildings with longnatural periods

As the Tohoku earthquake occurred in thenortheastern part of Japan and the amplifying
accretionary wedge8 is not on the propagation
path, the amplification of long-period component
in Tokyo Metropolitan area is expected to be a
bit small, which agreed with the observation
results. Many good quality observed groundmotions at various places can be used to verify
the proposed site coefficient in the tentative new
proposal for long-period earthquake groundmotion prediction based on observation data. The
response observations of super high-risebuildings in Tokyo, Nagoya and Osaka, can also
be used for validation study. HERP is planning to

Prediction map of long-period earthquake groundmotions in 2009 (draft) was announced from the
HERP, MEXT, in which earthquake motions for
expected Tokai earthquake, Tonankai earthquake,and Miyagi-Ken-Oki earthquake are predicted,
which raised a social concern on the long-period
earthquake ground motions caused by megaearthquakes at the subduction zone near trench.
The MLIT and the NILIM has been working forthe practical solutions for prediction of longperiod earthquake ground motions based on
observation [5.4] with the assistance by BRI,

8 Thick sediment along Nankai Trough is thought toamplify the long-period component of ground motion.

56

develop source model even for combined
earthquakes by the next spring, which can bemade use of brushing up the tentative new
proposal.

investigation tool considering the cost in the fieldof residential land, thus the technical informationin the civil infrastructure field need sometranslation as the investigation tool is generally
in different.

(4) Outline of liquefaction countermeasure forresidential land of detached housings
Structural calculation is released for woodhouses in the Building Standard Law. Thus, theliquefaction
countermeasures
cannotbeconsidered in the building construction for thedetached housings. In fact, it was thought theliquefaction countermeasure is the issue of theland development and not of the housing
construction.

7. CONCLUSIONSThis paper presents outlines of the strong motion
observations recorded by the BRI strong motion
observation network etc. at in and out of thebuildings of various structural types, and of the
motion induced and tsunami induced building
damage field-surveyed by NILIM and BRI in theoccasion of the 2011 off the Pacific coast of
Tohoku earthquake (the Great East Japan
Earthquake).
“Tsunami”,“non-structuralelements”, “long-period earthquake groundmotion”, and “liquefaction” are identified asimportant administrative issues to be urgently
countermeasured in the building structural codes,
and lastly the outline of on-going coping
activities on these issues by NILIM and BRI
collaborated with the administration is
introduced.

To answer for the social demand in the consumer
protection on liquefaction of residential land, a
study is planned on the application of the systemof performance indication9 of detached housings.
It is the investigation on indicator of liquefaction
information for detached housings, and the study
items are 1) study on the validation of existingliquefaction
prediction
methods
andcountermeasuring construction methods, 2) study
on the information indicator for liquefaction, and3) knowledge and information collection onliquefaction prediction and countermeasuremethods in the previous investigation andtechnology development. The execution team is
now under the selection as of August 19, 2011.

8. ACKNOWLEDGMENTS
We would express deepest condolence to thevictims of the earthquake and tsunami and theirfamily members as well as those who are
affected. We also would like to give hearty
thanks for the outpouring of support andsolidarity given by all parts of the world to theJapanese people.

The liquefaction phenomenon is a big issue not
only for detached housings but also for civil
infrastructures related to sewerage, river, road,and harbor. In MLIT, technical examination
council [6.2] on liquefaction countermeasures
was established and the technical information ineach field is continuously exchanged. Urayasu
where subject to devastating liquefaction damage
establishedtechnical
examinationandinvestigation council [6.3] on liquefaction
countermeasures, and Tokyo Metropolitan alsoestablished similar council [6.4]. Each council
has just started its study, but it is expected thatthe technical knowledge obtained in each council
be unified into common goal. Here, it should be
noted that the Swedish weight sounding test
method may be the available foundation

9. REFERENCES[1.1] MLIT and NILIM: Tentative new proposal
for countermeasure against ling-period
earthquake ground motion of super high-risebuildings and seismically isolated buildings,
Dec. 21, 2010. http://www.mlit.go.jp/report/press/house05 _hh_000218.html (in Japanese)

9 Grading system for houses newly constructed or existing

one which is lead on the occasion of the enforcement of
the Housing Quality Assurance Act.

57

[3.2] Naohito KAWAI ： Quick Report of
Damage Survey on Buildings Due to The
2011 Off The Pacific Coast of Tohoku
Earthquake by Kogakuin University Survey
Team for Wood Buildings, Quick Report of
Damage Summary Survey in Osaki city and
Ichinoseki City on April 11. (An article on theway), non-publication document.
[3.3] TheJapan
Building
Disaster[1.2] NILIM, BRI: Quick Report of the Field
Survey and Research on “The 2011 off the
Pacific coast of Tohoku Earthquake” (theGreat East Japan Earthquake), May 2011.
http://www.kenken.go.jp/japanese/contents/
topics/20110311/0311quickreport.html(inJapanese)[1.3] Cabinet Office: Guidelines for tsunami
evacuation building, June 2006. http://www.
bousai.go.jp/oshirase/h17/tsunami_hinan.html(in Japanese)[1.4] MLIT,
NILIM:
Grant-in-aid
formaintenance and promotion of building codes.
http://www.mlit.go.jp/jutakukentiku/house/jut
akukentiku_house_fr_000037.html(inJapanese)[1.5] U.S. Geological Survey (USGS): HistoricWorld Earthquakes, Earthquake Hazards
Program.
http://earthquake.usgs.gov/
earthquakes/world/historical.php[1.6] National Research Institute for Earth
Science and Disaster Prevention K-NET,
http://www.k-net.bosai.go.jp/[1.7] National Police Agency: Damage situationand police action on the 2011 off the Pacificcoast of Tohoku earthquake, August 18, 2011.
http://www.npa.go.jp/archive/keibi/biki/higa
ijokyo.pdf (in Japanese)[1.8] Press Release by Urban Bureau of MLIT:
Damage Condition by the Great East Japan
Earthquake, August 4, 2011. http://www.mlit.
go.jp/common/000162533. pdf (in Japanese)[2.1] Yoshida, Y., H. Ueno, D. Muto, and S.
Aoki, Source process of the 2011 Off the
Pacific Coast of Tohoku earthquake with the
combination of teleseismic and strong motion
data, Earth Planets, and Space, 58, pp.1-5,
2011[2.2] BRI Strong Motion Network Website:
http://smo.kenken.go.jp/[2.3] T. Kashima and Y. Kitagawa: Dynamic
Characteristics of Buildings Estimated from
Strong Motion Records, Proceedings of the
8th U.S. National Conference on Earthquake
Engineering, Paper No. 1136, December 2005
[3.1] Masato MOTOSAKA：The 2011 Off The
Pacific Coast of Tohoku Earthquake - Quick
Report of The Damage Survey http://japonism.org/wpcontent/uploads/2011/04/motosaka-report.pdf

Prevention Association: Standard for
Seismic
Evaluationof
Existing
Reinforced Concrete Buildings, 2001
(English Version in 2005)[3.4] National Institute for Land andInfrastructure Management, Ministry of Land,
Infrastructure and Transport, Japan and
Building Research Institute, Independent
Administrative Institution, Japan: Damage
Investigation of Buildings due to the Mid
Niigata Prefecture Earthquake, pp.305-353,
October, 2006 (in Japanese)[3.5] Takashi Hasegawa, Akiyoshi Mukai,
Kazuo Nishida and Tadashi Ishihara: Damage
Investigation of Steel Gymnasiums Due to the
Niigataken-chuetsu Earthquake (Part1 Studyon structural damage), Summaries ofTechnical Papers of Annual Meeting, AIJ, B-2,
pp.569-570, September, 2005 (in Japanese)[3.6] Kazuo Nishida, Akiyoshi Mukai, Takashi
Hasegawa and Tadashi Ishihara: Damage
Investigation of Steel Gymnasiums Due to the
Niigataken-chuetsu Earthquake (Part2 Studyon nonstructural damage), Summaries ofTechnical Papers of Annual Meeting, AIJ, B-2,
pp.571-572, September, 2005 (in Japanese)[3.7] The Japan Building Disaster Prevention
Association: Damage evaluation standard andrepair technology guidelines of earthquake
damaged buildings, August, 2002 (inJapanese)[4.1] Fire and Disaster Management Agency:
Damage statistics of the Great East Japan
Earthquake on March 11, 2011.8.11 (inJapanese).
[4.2] The Cabinet Office: Guidelines for
Tsunami Evacuation Buildings, 2005.6 (inJapanese)[4.3] NILIM : Announcement of the Selectionof the Interim Report on “Investigation on thebuilding structural codes in the area of58

tsunami danger” by Institute of Industrial
Science, Tokyo University, July 2011 (inJapanese).
http://www.nilim.go.jp/japanese/organization/kenchiku/iinkai/20110818pdf/si
ryou1.pdf[5.1] The Central Disaster Management Council,
CAO (2008), Published Committee material,
Committee for Technical Investigation on
Tonankai-Nankai earthquake. (in Japanese)[5.2] The Headquaters for Earthquake Research
Promotion, “Tentative Predictive Maps forLong-Period Earthquake Motions”, MEXT,
September, 2009 (in Japanese)[5.3] Architectural Institute of Japan (2007),“Structural Response and Performance forLong Period Seismic Ground Motions,” AIJ.
(in Japanese)[5.4] Okawa, I. et al., “Study on the Safety
Countermeasures
forSuper-high-rise
Buildings etc. against the Long-period
Earthquake Ground Motions”, Building
Research Data, No.127, December 2010,
pp.1-453, Building Research Institute (inJapanese)[5.5] The Building Center of Japan (1986),
Building Letter 1986.6, BCJ (in Japanese)[5.6] BRI and BCJ (1992), “Technical Guideline
for Making Design Earthquake Motions,”
BC J (in Japanese)[5.7] Kataoka,
S.
(2008),“Attenuation
Relationship and Amplification Map for
Ground Motion in Rather-Long Period
Range”, Journal of the Japan Society for
Civil Engineers, Vol.64, N0.4, pp.721-738,(in Japanese)[5.8] Satoh, T. et.al. (2010), “Prediction of
Waveforms of Long-Period Ground Motionsfor Hypothetical Earthquakes Using
Empirical Regression Relations of Response
Spectra and Phase Spectra,” J. Struct. Constr.
Eng., AIJ, Vol.75, No.649, pp.521-530 (inJapanese)[5.9] Izumi, M., et.al., (1983), “A Fundamental
Study on Extraction of Phase-Information in
Earthquake Motions, Transactions of AIJ,
Vol.327, pp.20-28 (in Japanese)[5.10] Ohsaki, Y., (1994), “Introduction toSpectral Analysis of Earthquake Motions”,

Kajima Publishing Co. Ltd.(in Japanese)[5.11] Tsurugi, M., et.al. (2005), “A Strong
Motion Prediction in Osaka Area for
Tonankai-Nankai earthquake”, Proceedingsof the Symposium on the Prediction of the
Broadband Strong Motions, JSCE and AIJ.
(in Japanese)[5.12] Sato, T., et. al. (2006), “Strong Motion
Prediction
for
Hypothetical
Tokai
Earthquake by the Research Council on
Design Input Motions in Aichi Prefecture,”
Proceedings of the Symposium on thePrediction of the Broadband Strong Motions(2), JSCE and AIJ. (in Japanese)[5.13] Kamae, K., et.al. (2006), “Strong Motion
Prediction in Kinki Region for Nankai
Earthquake,” Proceedings of the 34th
Symposium on Ground Vibration, AIJ (inJapanese)[5.14] Sekiguchi, H., et.al., (2006), “A MultiScale Inhomogeneous Model for thePrediction of Broadband Seismic Wave due
to Mega-Interplate Earthquake and Its
Application to Nankai Earthquake”,
Proceedings of the Symposium on thePrediction of the Broadband Strong Motions(2), JSCE and AIJ.(in Japanese)[6.1]. Yoshiaki Nakano: Design Load Evaluation
for Tsunami Shelters based on Damage
Observations after Indian Ocean Tsunami
Disaster due to the 2004 Sumatra Earthquake,
AIJ J. of Technology and Design, Vol.13
No.25, 337-340, Jun., 2007 (in Japanese)[6.2] Technicalexamination councilonliquefaction countermeasures in MLIT (inJapanese). http://www.mlit.go.jp/report/press/kanbo08_ hh_000142.html.
[6.3] Technical examination and investigation
council on liquefaction countermeasures in
Urayasu City (in Japanese). http://www.city.
urayasu.chiba.jp/item26068. html
[6.4] Technical examination and investigation
council on liquefaction countermeasures inTokyo
Metropolitan(inJapanese).
http://www.metro.tokyo.jp/INET/KONDAN/2011/07/40l7k400.htm (in Japanese).

59