Proceedings of the International Symposium on Engineering Lessons Learned fromthe 2011 Great East Japan Earthquake, March 1-4, 2012, Tokyo, JapanQUICK REPORT OF 2011 VAN EARTHQUAKEKoichi KUSUNOKI1, Akira TASAI2, Yo HIBINO3, Hidekazu WATANABE4,Muneyoshi NUMADA5, Mucip TAPAN6 and Alper ILKI7
1

Associate Professor, Institute of Urban Innovation, Yokohama National University, Japan,
kusunoki@ynu.ac.jp
2
Professor, Institute of Urban Innovation, Yokohama National University, Japan, tasai@ynu.ac.jp
3Assistant Professor, Structural Engineering Research Center, Tokyo Institute of Technology, Japan,
hibino@serc.titech.ac.jp
4Assistant Professor, Department of Architecture, Graduate School of Engineering, Hiroshima
University, Japan, hidekazu-watanabe@hiroshima-u.ac.jp
5Research Associate, The International Center for Urban Safety Engineering, Institute of Industrial
Science, The University of Tokyo, Japan, numa@iis.u-tokyo.ac.jp
6
Assistant Professor, Faculty of Engineering & Architecture, Department of Civil Engineering,
Yuzuncu Yil University, Turkey, mucip.tapan@gmail.com
7
Professor, Civil Engineering Faculty, Istanbul Technical University, Turkey, ailki@itu.edu.tr

ABSTRACT: On October 23, 2011 at 10:41:21 UTC, an intense earthquake (Mw=7.1
according to USGS) occurred in eastern Turkey. Another earthquake (Mw=5.6 accordingto USGS) occurred around Van city on November 9, 2011 which also caused the collapseof buildings weakened by the first shock. AIJ and JAEE organized a survey team after
the events. The team was dispatched to Van and Ercis cities, Turkey, and conducted
initial damage assessment in the damaged area with the survey groups from Yuzuncu Yil
University, Bogazici University and mainly Istanbul Technical University. This reportoutlines the findings obtained from the survey of the damaged area.
Key Words: 2011 Van earthquake, damage reconnaissance, R/C buildings, Masonrybuildings, Damage classification

OUTLINE OF THE EARTHQUAKEOn October 23, 2011 at 10:41:21 UTC, an intense earthquake (M7.1) occurred in eastern Turkey(Location: 38.691°N, 43.497°E). The focal depth was 16 km (USGS). The epicenter was 16 km (9miles) NNE from Van city. Another earthquake (M5.6) occurred around Van city on November 9, 2011
which also caused the collapse of buildings weakened by the earthquake on October 23.
These continuous seismic motions caused widespread destruction in the area of Ercis-Tabanli-Van.
Many inhabitants in the affected areas lost their houses by seismic motions. The death toll wasconfirmed respectively 604 and 40 people by the earthquake of Oct. 23rd and November 9th indamaged area according to Disaster and Emergency Management Presidency of Turkey (AFAD). A total of
2,300 people were seriously injured or slightly injured. 14,618 buildings and houses were damaged inthis area (USGS).

1950

OUTLINE OF THE INVESTIGATION
After the events, Architectural Institute of Japan (AIJ) and Japan Association of Earthquake
Engineering (JAEE) decided to dispatch a reconnaissance team to the affected area collaborating withTurkish reconnaissance team. The members of the team are listed on Table 1.
Table 1 Members of reconnaissance team
Koichi Kusunoki
Akira Tasai
Yo Hibino
Muneyoshi Numada
Hidekazu Watanabe
Alper Ilki
Cem Demir
Mustafa Comert
Mucip Tapan
Kutay Orakcal
Mubin Uslu
Hamdi Ates
Ahmet Sahin

AIJ team leader, Yokohama National University, Japan
Yokohama National University, Japan (AIJ)
Tokyo Institute of Technology, Japan (AIJ)
Institute of Industrial Science, The Univ. of Tokyo, Japan (JAEE)
Hiroshima University, Japan (AIJ)
Istanbul Technical University (ITU)
Istanbul Technical University (ITU)
Istanbul Technical University (ITU)
Yuzuncu Yil University
Bogazici University (BU)
Istanbul Technical University (ITU)
Istanbul Technical University (ITU)
Istanbul Technical University (ITU)

The team started reconnaissance at December 22nd in central area of Van city, and continued until 27th.
Reconnaissance was conducted in Ercis area at December 23rd, where is about 70km north from
central Van city and severely affected by the earthquakes of Oct. 23rd. The route of the investigation isshown in Fig. 1. Investigated buildings are listed below;

Fig. 1 Route of the investigation

Nineteen apartment buildings (7 were investigated in detail)Five schools
Five commercial buildings
Five masonry residential houses
Five mosques

1951







Four public buildings (all were investigated in details)
Four factories
Four bridges
One airport terminal
One non-engineered reinforced concrete residential house

BUILDING DAMAGESIn this section, outline of the damages of 4 buildings drawn in Fig. 1 and other typical damages
observed in the affected area are shown.
School building in Alakoy
The school building shown in Photo 1 is located in Alakoy and consisted of structurally independent
two reinforced concrete buildings stand side by side: three-story and two-story reinforced concretebuildings. The three-story building was severely damaged.
The second floor plan of the buildings and damage patterns are shown in Fig. 2. The details ofdamage are written beneath the column depicted by rectangular in Fig. 2. The three-story building has
four spans in the longitudinal direction and three bays in the transverse direction, and those of span
lengths are shown in Fig. 2. The columns are arranged in the same direction, except the column on thewest side, beside the entrance indicated as a triangle symbol. The typical geometry of cross section of
the columns shown in Fig. 2 has eighteen 16 plain bars, a 10 plain bar hoop spaced at 250 mm
approximately, and 20 mm of concrete cover. A clear height of 2.1 m at the second floor was assumed.

(a) Front view

FlexuralFailure(b) North-west side of view
Photo 1 Overview of building
FlexuralFailure

Flexural
FailureFlexural
FailureFlexural
Failure500 mm

3.5 m
ES

Shear
FailureFlexural
FailureFlexural
FailureFlexural
FailureFlexural
FailureFlexural
FailureFlexural
FailureFlexural
FailureFlexural
FailureFlexural
Failure3.2 m

W

300 mm

NFig. 2 Second floor plan and damage pattern of columns

1952

Photo 2(a) shows details of a west side column failed in shear. Concrete of the core was splitted off by
the shear crack and the longitudinal reinforcement buckled. All the columns failed in flexure innorth-south direction except the west side column as shown in Photo 2(b). Photo 3 shows theexpansion joint between two buildings and approximately gap of 60 mm at the top of the second floor
column observed. The unreinforced concrete masonry wall was damaged and had several shear cracks
of non-structural components.

(a) West side column failing in shear(b) Column flexural yielding at the top
Photo 2 Details of damaged columns

Photo 3 Expansion joint between two buildings
The story shear strength of the three-story building was calculated by assuming the ultimate shear
strength of columns at the second floor. The ultimate flexural strength and shear strength of thecolumns was calculated by Eq. (1), (2) and Eq. (3), respectively, and the minimum of those strengths
was used as the ultimate shear strength of the column.

NM u  0.8  at   y  D  0.5  N  D  1  b  D  B Qmu  2M u h

 0.068 pt0.23   B  18 Qsu  
 0.85 pw   wy  0.1 0   b  j M  Q  d   0.12
1953(1)(2)(3)

where at: total area of main bars in tensile (mm2), σy: yield strength of main bar (MPa, assumed as220MPa), D : height of column (mm), N: axial force (N, calculated from floor area supported by thecolumn and 12kN/m2 as unit weight), b:width of column (mm), σB: concrete strength (MPa, assumed
as 16MPa by concrete core tests), h: clear height of column (mm), pt:=100at/(b·D), M/(Q·d): assumed
as h/(2·d) if M/(Q·d)<1 then M/(Q·d)=1, if M/(Q·d)>3 then M/(Q·d)=3, pw: =aw/(b·s), aw: total area ofhoop (mm2), s:hoop pitch, σwy: yielding strength of hoop (MPa, assumed as 220MPa), σ0: =N/(b·D),
and j :=(7/8)d.
The calculated ultimate strengths of the columns are listed on Table 2. The story shear strength of
the floor is calculated as 674.4 kN, and the base shear strength coefficient, CB is calculated by using
the floor weight of two floors (2,688 kN) as 0.25. The west side end column was judged as failing inflexure as shown in Table 2, hence material property or bar arrangement detail are need to bediscussed.
Table 2 Calculated strengthsb×D(mm×mm)
500×300
300×500

Qmu (kN)
45.2
41.6

Qsu (kN)

Qsu/Qmu

Qu (kN)

134
2.96
45.2
170
4.08
41.6
Story shear strength (kN)

Number of columnΣQu (kN)

141632.8
41.6
674.4

School building in Gedikbulak
The building is three stories reinforced concrete building which is located at a village apart around 2
kilometers from the epicenter of the main-shock (October 23rd). The building was constructed insometime from 1980 to 1990. All stories completely collapsed by the earthquake as shown in Photo 4.
Fortunately no students and no teachers were killed, because the earthquake occurred on holiday.
Since no structural and construction information is available, unquestionable reason of the collapse isunknown. Many beams and columns were observed to be separated at the join as shown in Photo 5(a).
The reasons of such premature failures at joints were because of short anchorage length of beam main
rebar to column and lack of confinement in the joint, as shown in Photo 5(b). The photograph also
shows the ineffective anchorage length in the bottom bars of beam, which demonstrates the structuraldesign and/or detailing was conducted only for vertical load, not for seismic load. Thus, the building
must have collapsed by separation of beams and columns at every joint one after another during theearthquake, without providing enough resistance of structural members.

(a) West side of view(b) East side of view
Photo 4 Overview of building

1954

(a) Separation between beam and column(b) Anchorage failure of beam main rebar
Photo 5 Details of damaged beam-column joint
Damage classification of four apartment buildings (Bahcelieveler Sitesi A-D)
Four apartment buildings as shown in Photo 6 were investigated. The buildings are six stories
reinforced concrete buildings, and their layout is shown in Fig. 3. The first and second floor plan withthe damage level in the longitudinal direction of structural members of Building A, B, C and D are
shown in Fig. 4 to Fig. 7, respectively. Photo 7(a) shows details of shear failure at the top of a southside column. The beam-column joint failure was observed in the south-east corner of Building C asshown in Photo 7(b).

Fig. 3 Building layout
Y4

Photo 6 Noth-east side view of the buildings

Ⅱ

Ⅲ

Ⅰ

Ⅰ

Ⅰ

Ⅱ

Ⅱ

Ⅲ?

?

Ⅲ

Ⅱ

Ⅱ

Ⅲ

ⅡⅡ?

?

Ⅱ

Ⅱ?

Ⅱ

Y3
Y2

Ⅲ

Ⅲ

N

Y1

Ⅰ
X1

Ⅰ
X2

Ⅰ
X3

Ⅲ
X4

Ⅱ
X5

Ⅱ
X6

Ⅲ

Ⅴ
X7

X8Fig. 4 Second floor plan and damage level of structural members (Building A)

1955

Y4
Y3
Y2

Ⅰ

Ⅲ

Ⅰ

Ⅰ

Ⅰ

Ⅰ

Ⅴ

Ⅰ

Ⅰ

Ⅰ

Ⅰ

Ⅰ

Ⅰ?

Ⅰ

Ⅰ

Ⅰ

Ⅰ Ⅱ

Ⅰ

Ⅰ

Ⅰ

Ⅲ

Ⅱ

N

Y1

Ⅰ
X1

Ⅳ
X2

ⅢX3Ⅰ
X4Ⅲ
X5Ⅰ
X6Ⅰ
X7Ⅱ
X8Fig. 5 First floor plan and damage level of structural members (Building B)

Y4
Y3N

Y2
Y1

Ⅲ

Ⅲ

Ⅱ?

?

Ⅲ

ⅤⅤ

ⅡⅡⅡ

Ⅱ

ⅡⅡ

Ⅱ

Ⅲ

ⅡⅡ

Ⅱ

Ⅰ

ⅡⅡ

Ⅱ

Ⅱ

Ⅱ

Ⅱ

Ⅰ

Ⅰ

X1

X2?
Ⅲ
X3X4

X5Ⅰ
Ⅱ
X6

X7

X8Fig. 6 Second floor plan and damage level of structural members (Building C)

Y4
Y3

N

Y2
Y1

Ⅲ

Ⅰ

Ⅰ

Ⅰ

Ⅰ

Ⅰ

Ⅰ

Ⅴ

Ⅱ

Ⅰ

0

Ⅰ

0

Ⅰ

Ⅰ

Ⅱ

Ⅱ

Ⅰ Ⅰ

Ⅰ

Ⅰ

Ⅰ

Ⅱ

Ⅴ
X1Ⅰ
X2

Ⅰ
X3Ⅱ
X4Ⅴ
X5Ⅱ
Ⅰ
X6Ⅰ
X7

Ⅲ
X8Fig. 7 First floor plan and damage level of structural members (Building D)

1956

(a) shear failure of south side column(b) beam-column joint failureof Building A (damage level V)(south-east corner of Building C)
Photo 7 Details of damages
The damage levels of the buildings in the longitudinal direction are classified in Table 3 using thedamage evaluation method (The Building Disaster Prevention Association of Japan 2001).In themethod, the damage level of building is evaluated using the residual seismic performance ratio, whichis calculated according to damage level of vertical structural members and the failure mode ofmembers. In the methods 1 and 2, the columns are assumed to fail in flexure and shear, respectively. It
can be seen from Table 3 that the damage classification using the method 2 is more severe than using
the method 1 in Buildings B and D.
Table 3 Damage classification of the buildings

Building A
Building B
Building C
Building D

Damage evaluation method
Method 1 (Flexural failure)
Method 2 (Shear failure)
Severe damage
Severe damage
Moderate damage
Severe damage
Moderate damage
Moderate damage
Minor damage
Moderate damageBuilding of Department of Water Management (Devlet Su isleri Binail)The building has three stories and one semibasement floor. South-east side of the building is shown in
Photo 8. The plan of the main building is shown in Fig. 4. The building is separated into three portions.
They are not connected but have gap between buildings. Building A was constructed in 1975 withround bar and hand-mixed concrete. Building B and C were constructed in 1993 with round bar andhand-mixed concrete. Building D is new and was constructed in 2009 with deformed bar andready-mixed concrete.

1957

Fig. 4 Plan of the main building

Photo 8 South-east side of the building

Photo 9 South side of Building C

Building C was severely damaged as shown in Photo 9. All columns yielded at the top and bottom
ends of column and residual deformation was measured as about 7 degree. The residual gap between
Building B and C at the second floor level is 30cm. Dimensions of all columns are the same, 200mm
by 500mm. Bar arrangements in the columns were also investigated through cracks and with radar.
There are four bars as main bar, of which diameter is 16mm, and diameter of hoop is 8mm withspacing of 200mm. The plan and column arrangement of building C is shown in Fig. 5. Clear heightsof columns, story heights, standing wall heights, and total height of the building are also shown in thefigure.
Horizontal strengths of the columns, Qu , are calculated as min (Qsu,Qmu) with Eq. (1) to Eq. (3),where j:  7 8  D  50 , D is in mm, and concrete strength is assumed as 10 MPa.
Table 4 shows the calculated strengths. Only the column with D of 500mm and h of 1700mm isevaluated to fail in shear, although it showed flexural failure. Material tests are needed to discuss thefailure mode. Story shear strength is calculated as 1006.01kN, CB=0.14.

1958

Fig. 5 Floor plan and column arrangement of building C

Table 4 Strength of columnsb (mm)
200
200
D (mm)
500
500
h (mm)
1700 2500
Num. of col.
44Qmu (kN)
84.7 78.07
Qsu (kN)
71.25 97.04
Qsu/Qmu
0.84
1.24
Qu (kN)71.25 78.07
ΣQu (kN)
285 312.28

1959

500
200
2500
330.1254.62
1.8130.12
90.36

500
500
200
200
2600 170045
23.83 44.61
43.91 55.37
1.84
1.24
23.83 44.61
95.32 223.05

Other typical damages
An assessment of Bridge, Airport, Railway, Industrial structures and residential houses is presented inthis part of the paper. The seismic motions did not cause any significant damage to bridges, airport
terminals and railway, but the damage of some of the industrial structures and the residential houses
were severe.
The type of bridges in damaged area was mainly simple concrete beam bridge (Photo 10(a)).
Some bridges employed rubber bearings to have the effect of the seismic isolation as well as forconsideration of thermal effects (Photo 10(b)). The use of airport terminal building was limited due tothe damage of airport building. It should be mentioned the damage observed by our team was limitedwith the damages of non-structural members. On the other hand, the airplane service was completelyrecovered by utilization the new terminal building, which was taken into service right after the second
earthquake (Nov.9th) (Photo 10(c)). The railway is normally used for international logistic service. The
railway was available after the earthquake with no heavy damage (Photo 10(d)). The small scaleindustrial structures in the old industry zone were partially damaged. The structural systems of typicalmanufacturing structures were RC frames and infill wall of concrete blocks (Photo 11(a)). Photo 11(b)shows the total collapse of a manufacturing building. The adobe houses were also severely damaged(Photo 12(a)). The out of plane failure on the wall was observed (Photo 12(b)).

(a) Bridge with no significant damage(b) Rubber bearing of photo(a)(c) Damage of airport(d) Railway with no significant damage
Photo 10 Damage of infrastructures1960

(a) Typical industrial structure(b) Collapse of an industrial building

Photo 11 Damage of infrastructures(a) Damage of adobe house(b) Out of plane failure

Photo 12 Damage of houses

CONCLUDING REMARKS
Damages of several residential and public buildings due to 2011 VAN earthquake are presented in thispaper. Most of severely damaged reinforced concrete buildings were built before 2000 with plainround bars as longitudinal reinforcement and hand-mixed concrete of low quality. Concrete coresamples were taken from buildings, and the drawings are obtained and confirmed with the buildings.
Further investigation is needed to find out the reason of the damage comparing with the buildings
which suffered no damage.

ACKNOWLEDGMENTS
The investigation was conducted by the joint investigation team between Turkey and Japan. We would
like to acknowledge the great help and support provided by Yuzuncu Yil University, Istanbul Technical
University and people in Van city. Ph. D students and Technicians of Istanbul Technical University andDr. Kutay Orakcal of Bogazici University also gave a great help to the investigation. Other than thelogistical and financial supports of Istanbul Technical University and Yuzuncu Yil University, theencouragement of Rectors of both universities Prof. Dr. Muhammed Sahin and Prof. Dr. Peyami Battal
is also acknowledged.
REFERENCES
The Japan Building Disaster Prevention Association (2001). “The standard of damage evaluation andthe guidance of repair technology for the buildings hit by earthquakes.”, Tokyo, Japan. (inJapanese)

1961