Building Damage Investigation ofthe 2010 Chile Earthquake and Tsunami Disaster
Taiki SAITO1, Susumu KONO2, Koichi KUSUNOKI3, Yousok KIM4, Tomoya MATSUI5,Masanori TANI6, Yo HIBINO7, Carlos ZAVALA8 and Patricia GIBU8
1Chief Research Engineer, IISEE, Building Research Institute(Tatehara 1, Tsukuba 305-0802, Japan)
E-mail:tsaito@kenken.go.jp
2Associate Professor, Kyoto University(Yoshida Honmachi, Sakyo-ku, Kyoto 606-8501, Japan)
E-mail: kono@archi.kyoto-u.ac.jp
3Associate Professor, Yokohama National University(79-1, Tokiwadai, Hodogayaku, Yokohama 240-8501. Japan)
E-mail: kusunoki@ynu.ac.jp
4Research Associate, Earthquake Research Institute, The University of Tokyo
(7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan)
E-mail: yskim@eri.u-tokyo.ac.jp
5Research Associate, Toyohashi University of Technology(1-1 Hibarigaoka Tenpaku-cho, Toyohashi 441-8580, Japan)
E-mail: matsui@ace.tut.ac.jp
6Research Associate, Kobe University(1-1 Rokkodai, Nada-ku, Kobe, 657-8501. Japan)
E-mail: mtani@port.kobe-u.ac.jp
7Research Associate, Materials and Structures Laboratory, Tokyo Institute of Technology(4259 Nagatsuda, Midori-ku, Yokohama 226-8503, Japan)E-mail: hibino@serc.titech.ac.jp
8Japan-Peru Center for Earthquake Engineering and Disaster Mitigation, National University of Engineering(Martin of Porres 161, San Isidro, Lima 27, Peru)
E-mail:czavala@uni.edu.pe, pgibu@uni.edu.pe

A great earthquake of magnitude 8.8 struck on the Pacific coast of Chile, at 3:34a.m. local time onFebruary 27, 2010, and the earthquake and Tsunami caused widespread damage in Chile. The group ofJapanese and Peruvian researchers conducted disaster investigation especially for buildings from 26 April
to 3 May, 2010.
Key Words : Chile Earthquake, building damage, reinforced concrete, RC quake resisting wall

1. INSTRUCTION
A great earthquake of Mw8.8 occurred at 3:34 A.M. on February 27, 2010 local time with the Pacific coastof Chile as the hypocenter. This earthquake collapsed or destroyed more than 810,000 buildings etc., resulting
in more than 1.8 million victims including 432 deaths (as of March 27). When the earthquake occurred, in Peru,
which a neighboring country of Chile, the Japan-Peru international joint research project, “Project for Enhancement of Earthquake and Tsunami Disaster Mitigation Technology in Peru” (JST-JICA Science andTechnology Research Partnership for Sustainable Development Project, representative researcher: Fumio
Yamazaki, professor at Chiba University, 2009-2014) was under way. Given that Peru and Chile are closely
related to each other in terms of the seismotectonic and natural/social environments, and hence the findings
obtained from the study on the great earthquake of Chile are expected to be mostly applied to Peru, withconsiderable ripple effects on other Latin-American countries, it was decided to perform investigation andinformation gathering on the damage caused by the earthquake and Tsunami that hit Chile, jointly with thecounterpart from Peru. In addition, it was also decided that the second investigation team (team leader: Susumu32Kawano) would be dispatched from the Architectural Institute of Japan to the site around the same period toperform a joint investigation.
The investigation was performed from April 26 to May 3, approximately two months after the earthquake.
Given the JICA Study Team (March 13 to 23) and a joint study team comprised of four societies (Japan Association for Earthquake Engineering, Japan Society of Civil Engineers, Japanese Geotechnical Society, andArchitectural Institute of Japan) (March 27 to April 8) already dispatched from Japan and the limited investigation days, this investigation was devoted chiefly to performing on-the-spot inspection of disaster-stricken
buildings, acquisition of design documents, hearing with relevant parties, and so on, with the objective ofelaborately investigating reinforced concrete buildings. While our activities included the investigation ofbuildings equipped with a base isolation or seismic control structures, we would like to report in this paper ourinvestigation results on the damage to reinforced concrete structures.

2. OUTLINE OF INVESTIGATION
The investigation was performed chiefly in principal cities (Santiago, Concepcion, and Viña del Mar) ofChile and the surroundings. Figure 1 was the investigation points and the locations of faults. Table 1 shows thelist of the investigated buildings. The results of our detailed investigation on the underlined buildings of thoselisted in the table are as follows.
Table 1(Santiago)
B1. Torre Titanium (vibration control)
B2. Ciudad Empresarial
B3. Edificio Leones 1300
B4. Sol Oriente 1 and 2
B5. Edificio Don Luis
B6. Edificio Don Tristan
B7. Edificio Don Luis
B8. Hall Arnoldo Hax (Catolica Univ., seismic isolation)
B9. Comunidad Andalucia (seismic isolation)

(4)
(1)

Fault

(2)

(Concepcion)
B10. Torre O'Higgins 241
B11. LINCOYAN 440 (Torre Livertad)
B12. CAUPOLICAN 518
B13. Alto Rio
B14. SALAS 1343
B15. LOS CARRERAS 1535
B16. ROZAS 1145 (Edificio Don Feodra)
B17. FREIRE 1965 (Edificio Centro Mayor)
B18. Plaza Mayor
B19. BARROS ARANA 272

(3)

4/27
4/28
4/29
4/30
5/1

Figure 1(1)
(1)
(2)
(2)
(4)

Investigated buildings

SantiagoSantiago
Concepcion
Concepcion, (3) Talcahuano
Viña Del Mar(Talcahuano)
B20.Edificio de Biblioteca Municipal de Talcahuano(Viña del Mar)
B21. Building Festival
B22. ACHS (Asociacion Chilena de Seguridad)(seismic isolation)
B23. Efidicio Rio Petrohue

Investigation points and locations of fault

3. INVESTIGATION RESULTS OF BUILDING DAMAGE(1) Damaged buildings in Santiago Citya) B4. Sol Oriente 1 and 2
It is an apartment complex constructed of box-frame-type reinforced concrete in 2007 with 18 stories above33

ground (2 stories underground) (Photo 1). The building was damaged particularly on the first basement level ofthe underground self parking lot (Photos 2, 3). The structural features and the summary of damage are follows:- Multi-story shear wall structure connected by flat slabs.
- Flexural tension failure occurred in three structure planes out of five 4-span ones on the first basement. An
end main reinforcement ruptured.
- The height of the north side multi-story shear wall on the basement is shorter by 1200 mm than on higherfloors. In addition, only the northern end of the north side multi-story shear wall lacks an orthogonal wall
(Figures 2, 3). Accordingly, the flexural strength of the north side multi-story shear wall is low on the firstbasement, likely resulting in the flexural tension failure in the south direction on the north side multi-story
shear wall.

Photo 1
Appearance of the building

Figure 2

Photo 2
Underground parking lot

Basement plan view

Figure 3

Photo 3
Shear wall on the first basement

Building section view (sketch)(2) Damaged buildings in Concepcion CityConcepcion City is a city located approximately 105 km away from the hypocenter with a population ofapproximately 220 thousand. The earthquake brought eight buildings into serious damage, of which one wascompletely collapsed. We could obtain entry permits to and design documents of several buildings thanks tothe cooperation of the Urban Development Bureau and the Police Bureau of Concepcion City.
a) B11. LINCOYAN 440 (Torre Livertad)
It is an RC wall flat slab structure constructed in 1973. The building has 17 stories above ground and one
basement (with no underground car park), of which the three lower floors are occupied by commercial tenants
and the fourth and above floors are used for housing (Photo 4). The machine room on the first basement washardly damaged. The non-structural brick wall collapsed more seriously on upper floors. The walls on the first34

and second floors failed in flexural tension with the wall-end main reinforcement fractured or buckled (Photo5). While the building was damaged particularly on the walls in the northeast and southwest directions, little
damage was observed on the walls in the orthogonal direction. The damage concentrated on the wall footing islikely attributable to the lack of flexural strength of the T section web resulting from the respective bending
deformation of two multi-story shear walls arranged in parallel due to the limited floor slab area in the staircase(Figures 4, 5, 6).

Figure 4
Building plan view
Photo 4
Appearance of the building

Figure 5
X-X' section view

2nd floor

Main Rebar

Figure 6
Failure mechanism of T-shaped section wall

Photo 5Wall fracture35b) B13. Alto Rio
It is a reinforced concrete apartment complex constructed in 2008 with 15 stories above ground and twostories underground (parking lot). The building completely fell down from the base on the first floor (Photo 6,7). Photo 7 shows the appearance of all the reinforcing bars on the first floor having been pulled out or cut
down from the wall pillars and load-bearing walls on the first floor during the overturning of the building.
Conversely, little damage was observed on the underground end plane walls. As shown in the plan view ofFigure 7, the walls on the first floor and the basements (parking lot) are smaller than those on the second andabove floors in both length and volume. This fact may have resulted in the damage particularly on the wall
footing on the basements.

Photo 6
Photo of the building before collapsed(excerpted from the Web Page)

Photo 7
Collapsed building

B1F

1F

1F

2520
3060
2520

2F
Figure 7 Difference in wall volume and layout among basement, first floor, and second floor36c) B14. SALAS 1343
It is an apartment complex constructed in 2007 with 13 stories above ground and an underground car parkprovided beside the building. It consists of two buildings arranged in L shape and connected with an expansion
joint (Photo 8, Figure 8). It is constructed with a middle corridor in planar shape with more wall volume in theridge direction. While the south side building was seriously damaged, the north side building was slightlydamaged. The south side building seems to have suffered torsional vibration caused by stiffness eccentricity
resulting from the many walls in the surrounding of elevators and staircases.

地下

駐車場
Undergroundparking lot
5620

4270

4270

2860

4120

2860

4270

4270

5620

810

3360

3020

3020

3580 520

810

階段NEV

Exp. joint4270

4270

2860

2900

3440

3690

エキスパンションジョイント部
階段5620

Photo 8
Appearance of the building

810

1F730 3360

3020

3020

3360

730

Figure 8

Plan view and damage(3) Damaged buildings in Viña del Mar City
Viña del Mar City is a city with a population of approximately 300 thousand. The 1985 Chile Earthquake(magnitude 7.8, 150 deaths) damaged many high-rise RC buildings within the city.
a) B21. Building Festival
It is an apartment complex (wall-type flat slab structure) with 14 stories above ground and one basement. Itwas severely damaged (Photo 9). The building had undergone seismic retrofitting such as the placement ofadditional concrete for walls and beams and the additional installation of walls in response to the earthquake in
1985, but suffered damage in the recent earthquake such as flexural tension failure and separation of concreteadded walls in the wall footing (Photo 10, Figure 9).

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Photo 9
Appearance of the building

Photo 10
Appearance of the building

Wall damage
at B1FNo damage at
floor beam

damage at floor
beam at 1F

damage at stair

too much bars

crack to 2F leveldamage
atretrofitted wallNot examined

Figure 9Plan view and damage

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4. SUMMARY
The characteristics of the damaged buildings are as summarized below.
Many of the damaged buildings are flat slab structures with no beam or frame column on the wall.
x
The standard size of wall reinforcement is D10@250-D.
x
At the wall end, confinement steel (or supplementary cross ties) is installed as well as bending reinx
forcement.
The wall pillars, which are provided in place of pillars, are arranged longitudinally in the span direction
xfor reasons of the layout of the parking lot. This fact may result in lower flexural strength and stiffness inthe ridge direction.
The length of a multi-story shear wall may be reduced in the underground parking lot space for the sake ofxvehicular traffic.
A parking lot in the underground of the building may be constructed in a shape protruded in one direction.
xIn this case, the parking lot is enclosed only by the three-side retaining walls immediately below thebuilding, with the other side of wall set back in the ridge direction.
Some walls or wall pillars in the span direction are not connected to orthogonal walls. Such walls include
xa wall extending in the span direction on the side without a retaining wall and a piloti-type wall pillar(ground parking lot). They were damaged probably due to the low flexural strength when the tensile load
was exerted to the side with no orthogonal wall.
The buildings have a relatively large number of stories and a high slenderness ratio. As a result, the walls
xof such buildings mostly underwent flexural tension failure. In addition, lack of enough strength to bear
the story shear force on the compression side may result in collapse of the building.
Most of the severely damaged or collapsed buildings were high-rise constructions with 13 or more stories
and damage concentrated on the footing of the multi-story shear wall observed as a common characteristic.
Conversely, most buildings in cities appeared to be sound and few buildings suffered intermediate damage, e.g.
slight or medium damage. This may be a characteristic of damage to box frame constructions without plastic
deformability. The damage can be considered generally minor, in view of the great magnitude of the recentearthquake at 8.8. While elaborate analysis is still required as to the extent of the seismic force applied to thebuildings, given the fact that the damage remained so modest after the great earthquake, the Chilean Seismic
Code seems to have functioned extremely well. One of the factors behind the major lack of damage to buildingsin the recent earthquake was the positive introduction of the load-bearing wall.
The Chilean Seismic Code includes a provision likely encouraging the positive introduction of theload-bearing wall such as a strict restriction of deformation and reduction of the design seismic force according
to the load ratio of the load-bearing wall. In Japan, the height of wall-type rigid-frame structures is limited to 15stories. Given the modest damage to buildings in the recent Chile Earthquake and the continuous usability of
post-earthquake buildings, Japan may also need to recognize anew the benefits of box frame constructions.
From the research perspective, a design method needs to be established to prevent such brittle failure after
flexural yielding as observed in the recent seismic damage. Structural testing on flexural failure of load-bearing
walls is not common in Japan and future research and development is awaited.

ACKNOWLEDGMENT
This damage investigation was performed as a part of the international joint research project “Project forEnhancement of Earthquake and Tsunami Disaster Mitigation Technology in Peru” (JST-JICA Science andTechnology Research Partnership for Sustainable Development Project, representative researcher: FumioYamazaki, professor at Chiba University, 2009-2014) and an earthquake disaster investigation of the Architectural Institute of Japan. In conducting this investigation, we obtained cooperation from many people including Professor Boroschek and Mr. Tomas of the University of Chile; Professor Cruz of the PontificalCatholic University; an ex-trainee, Mr. Raul; and the JICA Chile Office. We wish to express our gratitude tothem.

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REFERENCES
1) Hiroto Kato, Seitarou Tajiri, Tomohisa Mukai: 2010 Chile Earthquake Field Survey Report (Flash Report), Building ResearchInstitute, April 2010
2) A study team from the Japan Association for Earthquake Engineering and the Architectural Institute of Japan: Damage Investigation
Report for Maule, Chile, Earthquake of 27 February 2010 dated May 20103) ‘Learning from Earthquake, The Mw 8.8 Chile Earthquake of February 27, 2010,’ EERI Special Earthquake Report, 2010.6.
4) Riddle, R., Wood, S.L. and De La Liera, J.C.: ‘The 1985 Chile Earthquake,’ A Report to the National Science Foundation, ResearchGrants ECE 86—03789, Univ. of Illinois, 1987.

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