Zavala, C. et al.

Paper:

Cyclic Behavior of Low Ductility Walls Considering
Perpendicular Action
Carlos Zavala, Patricia Gibu, Luis Lavado, Jenny Taira,Lourdes Cardenas, and Luis Ceferino
Laboratory of Structures, Japan-Peru Center for Earthquake Engineering Research and Disaster Mitigation (CISMID),
Faculty of Civil Engineering, National University of Engineering (UNI)
Av. Tupac Amaru 1150, Puerta 7, Campus UNI, Lima, Peru
E-mail: czavala@uni.edu.pe[Received November 12, 2012; accepted January 8, 2013]

Low ductility wall buildings became part of the Peruvian construction boom in the first decade of the 21st
century. Through government promotion under the“Mi Vivienda” (“My house”) program, the construction of low rise buildings of 5 stories using walls withwire mesh reinforcement, provided a partially solutionof an apartment deficit, at reasonable cost. The heightsof buildings started to grow, reaching 12 to 16 stories. In the design of these walls, provisions recommend walls corners confinement, because the actionof the walls ensemble provide limited ductility underseismic behavior. A comparison of H-shaped wall with
one-plane wall is presented in this paper. Here, an experimental test has been performed by a cyclic loading
test considering the action of a constant axial load of
40 kN, where the elastic stiffness of H-shaped wall ishigher than that of a one-plane wall. Also resistant of
the H-shaped wall increases, but ductility in both walls
remains similar.

Keywords: low ductility wall, concrete wall Perpendicular effectsign standards. In 2003 the Peruvian Concrete Standards
Committee published an addendum that included recommendations for the design of low ductility walls. By thattime new research had been performed on walls and fullscale tests, like in the study of Eng. Gabriela Medina at
CISMID Structural Lab, with the support of UNICONFORSA-PRODAC. This study produced parameters considered as a high limit of stress for these walls. Since thattime low-ductility walls have been widely used in middle
and low-rise buildings in Peru. Since in low rise buildings, the behavior of these walls had a predominant shear
failure, however during the knowledge gap on the standards, buildings of 12, 14 and 16 stories were build under
unknown criteria.
One of the concerns here is to understand when flexural behavior will be predominant and for what number ofstories. Also, how is the influence in the stiffness fromthe perpendicular wall against one-plane wall. In this paper the compares the action of a perpendicular wall witha one-plane wall. Here an experimental test is presented
by using cyclic lateral loading considering the action of aconstant axial load.

1. Introduction

2. Main Differences Between a Low Ductility
Wall and a Standard Wall

In 1997 as the initiative of Professor A. Galvez, who
propose the idea of replacing the masonry wall bricks
with a thin concrete wall, brought the opportunity to the
CISMID Structural Lab to start in Peru the study of low
ductility walls. The purpose of studying the behavior ofthese walls using low strength concrete ( fc = 100 kg/cm2 )and the reinforcement of Q62 wire mesh became a benchmark of the study for walls to be used in 4 storey buildings. In that research, walls with very light reinforcement
and low compressive stress, are considered as lower stresslimit for this kind of walls. However number of stories
in buildings grows between 1997-2003 as in Fig. 1. Investigations like those performed by UNICON-PRODAC
at the PUCP Structural Lab, were used as basic material for discussion among the members of the Peruvian
Concrete Standards committee to fill the gap of the de-

In Fig. 2 two of the main differences between a low
ductility wall and a standard concrete wall are presented.
The first difference is the thickness of the wall, where alow ductility wall could be 100 mm or even 80 mm versus
the 150 mm that is the minimum thickness of the standard
concrete wall.
The second difference is reinforcement showing deformed ductile bars at the edges of the walls and electro
welded wire mesh on the center of the wall. Also connection between wire mesh through dowels tied from basement or tied from lower story will produce uniformity,
against the deformed bars on center of the wall used in
the standard concrete wall.
Figure 3 presents the difference in construction wherebuilders offer a production of story and slab per day as anefficiency parameter. However this massive and continu-

312

Journal of Disaster Research Vol.8 No.2, 2013

Cyclic Behavior of Low Ductility Walls Considering Perpendicular Action

200

100

Fig. 1. Low ductility wall.
Fig. 4. Load condition for H wall and deformation undershear stress component.

posed to be to 5 story buildings, but many construction
companies started immediately building structures of 12,
14 and 16 stories, without confinement columns.
On 2003 the NTE-060 Peruvian Concrete Standard include recommendations for design and construction of
low-ductility walls. Stiffness contribution of the perpendicular wall is need in order to find how contribute on the
inelastic behavior under lateral load with and without perpendicular wall.
Fig. 2. Low ductility wall reinforcement and configuration.

3. Construction

Fig. 3. Construction process.

ous placement brings failures, however, such cold joints
at bases of walls or air bags inside the concrete. It increases the time needed in the construction process due toactions for repair these deficiencies. After a series of bad
experiences, some builders propose the use of fluid concrete with fibers in order to reduce the total time needed
for construction.
From 1998 to 2003, non regulation was applied in thedesign and construction of low-ductility walls due to they
were not qualify as shear walls. The application was supJournal of Disaster Research Vol.8 No.2, 2013

3. Theoretical Influence of the Perpendicular
Wall Effect
For a theoretical investigation of the influence of theperpendicular wall versus the in-plane wall, we consideran H-shaped wall of 2500 mm in length, and 2600 mm
in height and 100 mm in thickness. In speaking of an Hshaped wall as a steel shape, the in-plane wall is a web,and the perpendicular walls are flanges of the wall. The
flange length is therefore 2500 mm, with the same height
and thickness as the web.
Theoretically speaking, walls under perpendicular action and combined load demand show primary axial deformation, due to the axial forces, assigned as dead load
and live load in the building design process. Therefore
these axial forces produced a pattern of axial stresses.
Seismic action then appears, lateral deformation changes
the configuration of axial stress and shear stress produces
concentration and also the dissipation of stress on the wall
flange.
As an example, the load configuration and the deformation of the H wall under a lateral load with a constantaxial load is presented in Fig. 4, for simulation developedwith SAP2000. Here, 200 kN axial load is applied, producing a confinement axial stress of 8 kg/cm2 . This axial stress is reduced by the application of the lateral load
to a level of 7.2 kg/cm2 on the web, and increase on the313Zavala, C. et al.

B f = 1 7 5 0 mm, B f /L = 0 . 7
σ 11 = 4 . 0 2 kg/cm2

B f = 1 5 0 0 mm, B f / L = 0 . 6
σ 11 = 4. 15 kg/cm2

B f = 12 50 mm, B f /L = 0 . 5
σ 11 = 4. 32 kg/cm2

Fig. 5. Horizontal stress on perpendicular wall for different
flange length – web length ratio.

Fig. 7. Maximum axial stress variation for B f /L ratio.

Wall Flange
Wall WebB f = 2 50 0 mm, B f /L = 1. 0, σ 22 = − 15 . 8 5 kg/cm 2

Wall Flange
Wall WebB f = 17 5 0 mm, B f / L = 0. 7, σ 22 = − 1 7 . 1 2 kg/cm2

Wall Flange
Wall WebB f = 1 5 0 0 mm, B f / L = 0 . 6 , σ 22 = − 1 7. 89 kg/cm2

Wall Flange
Wall WebB f = 12 5 0 mm, B f / L = 0 . 5, σ 22 = − 1 8 . 9 7 kg/cm2

Fig. 6. Horizontal stress variation for B f /L ratio.

σσ

toe to 18 kg/cm2 near the intersection of web and flange.
Also horizontal stress on the flange wall shows the average value of a level of 4.0 kg/cm2 . Consider the variationin the geometrical parameter flange length, and produce
the variation in the flange length and web length ratio forthe component of the horizontal stress. Results of the investigation are presented in Figs. 5 and 6.
If is σrepeatedσ the example σ
to investigate
the change ofσσσ
stressinthe
axial
component
in
the
H
wall,
consideringσσσthat this kind of stress will have an initial level of axial
stress of 18 kg/cm2 , producing the stress change function
with the B f /L ratio is presented on Fig. 7. Fig. 8 presents
the stress distribution for each case. If we consider thedivision in elements and the amount of the elements on theflange wall, we can find that stresses have a similar levelof axial stress for b f /4. It means as long is the flange lessincrement on the axial stress is reached.
Let’s consider the variation in the shear stress underconstant axial and shear force. Fig. 9 presents the patternsof the shear stress for different values of B f /L. We musttake into account that 6.85 kg/cm2 is the starting point,since the value will decrease as the B f /L ratio decrease
as is presented at Fig. 10a.
Also the ratio between B f /L and shear stress for theflange wall is presented in Fig. 10b, where the level ofshear stress on the flange wall is almost the same as the314

Fig. 8. Axial stress on perpendicular wall for different
flange length - web length ratio.

shear stress of the web stress. The tendency of the stress isalmost the same, stress decrease as B f /L ratio decrease.
It means less flange less stress.

4. Experimental Test Considering Perpendicular Wall Effect
In order to investigate in experimentally the influenceof the perpendicular wall on and H-shaped configuration
versus one-plane wall, two experiments were performed:
Journal of Disaster Research Vol.8 No.2, 2013

Cyclic Behavior of Low Ductility Walls Considering Perpendicular Action

Wall Flangeτ 12 = 3. 30 kg/cm2
B f = 25 0 0 mm

Wall Webτ 12 = 6 . 9 6 kg/cm2
B f / L = 1. 0

Wall Flangeτ 12 = 3 . 0 7 kg/cm2
B f = 1 7 5 0 mm

Wall Webτ 12 = 6 . 7 0 kg/cm2
B f / L = 0. 7

Wall Flangeτ 12 = 2 . 9 3 kg/cm2
B f = 1 50 0 mm

Wall Webτ 12 = 6 . 5 5 kg/cm2
B f / L = 0. 6

Wall Flangeτ 12 = 2. 73 kg/cm2
B f = 1 2 5 0 mm

Wall Webτ 12 = 6 . 3 1 kg/cm2
B f / L = 0. 5

Fig. 9. Shear stress on wall and web walls.

Fig. 11. Test specimen configuration for H-shaped wall.

an experiment on a one-plane wall, and an experimentwith a perpendicular wall that produces an H-shaped wall.

(a)

(b)
Fig. 10. Shear stress variation for B f /L ratio.

Journal of Disaster Research Vol.8 No.2, 2013

4.1. About the Specimens
Both walls, one-plane and H-shaped wall have the same
dimensions: 2500 mm in length with 2600 mm in heightand 100 mm in thickness. In the case of the H-shaped
wall, a flange with a total dimension (B f ) of 2500 mm isincorporated into the one plane wall, in order for investigated the influence by the measured stresses.
The walls have confined reinforce on the corners of 3bars #4. Wire mesh appears as reinforcement of the web
and flange with electro welded mesh Q-158 (5.5 mm diameter 0.15 m As = 1.58 cm2 /m). Is common the useof 600 mm dowels between stories on buildings, but inthe case of the specimens dowels has same growing fromthe footing base. Fig. 11 presents the configuration ofboth specimens, one-plane and H-shaped wall. Noted that
there is a horizontal border beam of 300 mm by 300 mm
section on the top of each beam. Also foundation of
900 mm by 300 mm is on the bottom part of the specimen.
The construction process tried to replicate as near thereal environment on the site area. So wire mesh from thefooting was fixed with the wire mesh of the wall and threeductile bars #4 were placed on the corners of the specimens. Wood forms were used to encase the reinforcement
315

Zavala, C. et al.

Fig. 13. History of cyclic displacement in test.

Fig. 12. Four stages in the construction of the specimens.
Fig. 14. Displacement transducer setting.

and set the fluid mix of concrete inside to produce theconcrete wall.
On the top of each wall a loading beam is set to be use
for as loading steel frame. Fig. 12 presents four stage ofthe constructions of the specimens.

5. About the Test Execution
For the execution of the test 2 jacks and one actuator
were used for the application of the loads. Axial loadequivalent to 200 kN that approximate represents the loadof four stories over the wall.
During the execution of the test, this load will be applied at the beginning of the load process, and after reaching 200 kN, the load will remain constant during thewhole test. To simulate lateral action such as earthquake
movement, an increasingly cyclic displacement is applied
to the specimen in order to start the movement of the walland to measure the load in each step. Fig. 13 presents thehistory of the cyclic displacement applied to the wall. The
displacement was applied using the new jack system provided by JICA under the SATREPS project. This jacks(Rikken System) had a capacity of 500 kN and 400 mm
stroke.
To measure displacement, transducers were placed tomeasure displacement at different locations on the walls.
On the one plane wall and web wall (on H-shaped specimen), displacements transducers were set at the locations
316

Fig. 15. Test set up for one plane wall and H-shaped wall.

presented on Fig. 14.
Here sensors on the wall were set on the diagonal, vertical and horizontal directions in order to reproduce thedisplacement in all directions. To measure stress at points,
strain gauges were glued to the surface of the concrete andto the reinforce bars. All the sensors and gauges, wereconnected to an scanning box and Tokyo Sokki TDS 530
data logger.
The test setup of both specimens is presented in Fig. 15.
Note here the difference in setup due to the need for the
Journal of Disaster Research Vol.8 No.2, 2013

Cyclic Behavior of Low Ductility Walls Considering Perpendicular Action
CISMID/FIC/UNI-JICA SATREPS Project
Low ductility concrete wall -Wall 02
18/02/2012

CISMID/FIC/UNI-JICA SATREPS Project
Low ductility concrete wall -H- Wall 03
04/06/2012
500

400

400

300

300

Base Shear (kN)

200

-20

100
-15

-10

0 -2.185, 7.25
-5
0
5
-100

10

15

20

Base shear (kN)

500

200
100
0
-20

-15

-10

-200

-5

-100

0

5

10

15

20

-200

-300

-300

-400

-400
Displacement (mm)-500
Displacement (mm)Fig. 16. Hysteresis curves of one plane wall and H-shaped wall.

࢚࣮ࣛ ཧ↷ඖࡀぢࡘ࠿ࡾࡲࡏࢇࠋCISMID/FIC/UNI-JICA SATREPS Project
Comparison Low ductility concrete wall - Wall 02 vs Wall 03
Lareal Load (kN)

500
400
300
200
100

-20.00 -16.00 -12.00 -8.00

0-4.00 0.00
-100

4.00

8.00

12.00 16.00 20.00

-200
-300
-400
-500
One Plane Wall - M2

displacement (mm)Wall - H - M3

Fig. 18. Final stage of one-plane wall and H-shaped walls.

Fig. 17. Comparison of behavior curves of low ductility walls.
Table 1. Test results on walls.
Initial Stiffness End Elastic Limit τmax Stress(kN/mm)Drift
Drift (kg/cm2 )One Plane Wall
185.2
0.00034 0.0040
14.5
Wall - H
192.0
0.00040 0.0015
14.5
Specimen

application of the axial load and lateral load simultaneously specially in the case of the H-shaped wall where
space is quite narrow to apply both loads. In the case of Hshaped wall the perpendicular wall (flange wall) has threelines of sensors in order to investigate the displacement at
those locations and dissipation of the stress. Strain gauges
were also set࢚࣮ࣛfor the same
purpose.
ཧ↷ඖࡀぢࡘ࠿ࡾࡲࡏࢇࠋ

6. Test Results
The cyclic displacement versus base shear on the experimented walls is presented in Fig. 16, where hysteresis
curves of the development of each test are presented. Bothspecimens had almost the same level of maximum stress,
but in different failure modes. The reason for this similarity in stress level is due to an slip on the foundation
occurs after 4 mm displacement. In the case of the oneplane wall, shear cracking appears at the base of specimen. Then flexural cracks then start to appear in bothborders elements, propagating horizontally. Finally diagonal cracks finally appear and a combination of shear failJournal of Disaster Research Vol.8 No.2, 2013

ure and slip failure at the base, is the final failure pattern.
Comparison of behavior curves is presented on Fig. 17.
In the case of the H-shaped wall, the starting crack wasa diagonal crack that appeared at the intersection between
both walls. A shear cut of the basement appears, together
with an up light of the toe. Final stage of both specimens
is presented in Fig. 18.
A summary of the results of both tests is summarizedin Table 1. Here in the case of the H-shaped wall stiffness
is increased due to the perpendicular wall action. Also
the end of the elastic zone in the specimens is also presented in Table 1. Here, the stiffer is the wall, lower theductility. The maximum drift value for one-plane walls
is 0.004 against the maximum drift on the H-shaped wallof 0.0015. Therefore, more rigider the wall, the lower theductility.
317

Zavala, C. et al.

Shear Stress (kg/cm2 )CISMID/FIC/UNI-JICA SATREPS Project
Comparison Low ductility concrete wall - Wall 02 vs Wall 03-0.008-0.006-0.004

16
14
12
10
8
6
4
2
0
-0.002 -20.000
-4
-6
-8
-10
-12
-14
-16
One Plane Wall - M2

0.002

0.004

Acknowledgements
The authors would to express their gratitude to the Ministry of
Education of Japan, through the Japan Science and Technology
Agency (JST) and the Japan International cooperation Agency(JICA) for the support the Japan-Peru SATREPS Project. Our
gratitude also goes to Dr. Fumio Yamazaki PI investigator of the
SATRPES project and promoter of this investigation.

0.006

0.008

References:

Drift
Wall - H - M3

Fig. 19. Comparison of shear stress on low ductility walls.

[1] CISMID Report, “Experimental test on walls to investigated lateralload Behavior AGV System CISMID/FIC/UNI,” 1998 (in Spanish).
[2] C. Zavala, et al., “Behavior under lateral load of low concrete
strength walls with electro welded wire mesh reinforcement,” Material Bank of Peru, AGV & Association, CISMID Report, 19992000.
[3] G. Medina, “Study of the behavior of low ductility and one
story scale model reinforce with electrowelded wire mesh,” Graduate Thesis, FIC/UNI, Research supported by UNICON-FORSA,PRODAC-CISMID/FIC/UNI, 2004-2005.

Figure 19 presents a comparison of shear stress behavior in terms of drift and shear stress in the web wall on
both specimens. The H-shaped wall has a elastic drift
limit smaller than the one-plane wall specimen, where thevalues are presented in Table 1. Both walls reach the samelevel of maximum shear stress but with different drift.

Name:
Carlos Zavala

Affiliation:
Researcher, Laboratory of Structures, CISMID
Professor, Faculty of Civil Engineering, National
University of Engineering (UNI)

7. Conclusions• The contribution of the perpendicular action of a wall

to one-plane wall has been presented theoretically inthis paper. The influence of the flange size of thewall shows the spreading of the stress for L/4 to lowlevels. It is necessary to continue the study using
experimental tests of different flange lengths.
• One case of flange length has been studied exper-

imentally with the execution of two test: the firsttest with a one-plane wall and second test with an
H-shape wall with a flange length of 250 mm. The
height of the walls is 2600 mm and 100 mm in thickness. Both walls have been reinforced on the corners
with 3 bars #4. Wire mesh appears as reinforcement
for the web and flange with electro welded mesh Q158 (5.5 mm diameter 0.15 m As = 1.58 cm2 /m).
• Test results are summarized in Table 1. In the caseof H-shaped wall, stiffness is increases due to theperpendicular wall action. Maximum drift value for
one-plane walls is 0.004 against the maximum drift
for the H-shaped wall of 0.0015. Therefore, therigider the wall, the lower the ductility.
• We need to continue the study in order to verify the

spread of stress in the perpendicular flange wall andweb wall. At this time we need to process data fromstrain gauges to investigate this spread of stress.

318

Address:
Los Ishipingos (Ex-Abetos) 245 Dpt. 202, Urb. El Remanso La Molina,
Lima 12, Lima, Peru

Brief Career:
1984 Undergraduate Course, Faculty of Civil Engineering, National
University of Engineering (UNI), Lima, Peru
1989 Master Course, Graduate School Faculty of Civil Engineering,
National University of Engineering (UNI), Lima, Peru
1995 Ph.D., Graduate School of Architecture, University of Tokyo, Japan
2001 Professor, Faculty of Civil Engineering, National University ofEngineering, Lima, Peru
2007-2012 Director of Japan Peru Center of Earthquake Engineering
Research & Disaster Mitigation CISMID

Selected Publications:• C. Zavala, K. Ohi, and K. Takanashi, “A general Scheme for
Substructuring On-line Hybrid Test on Planar Moment Frames (TheNeural Network Model),” Proceedings of 4th Pacific Steel Structures
Conference, Pergamom Press, October 1995.
• C. Zavala, “Improvement on low cost housing through non-conventional
construction systems,” Proceedings of the 12th World Conference on
Earthquake Engineering, Auckland, New Zealand, February 2000.
• C. Zavala, C. Honma, P. Gibu et. al, “Full Scale On Line Test On Two
Story Masonry Building Using Handmade Bricks,” Proceedings of the 13th
World Conference on Earthquake Engineering (WCEE), Vancouver,
Canada, August 2004.
• C. Zavala, Z. Aguilar, and M. Estrada, “Evaluation of SRSND Simulator
against Fragility Curves for Pisco Quake,” Proceedings of the 8thInternational Conference on Urban Earthquake Engineering Tokyo
Institute of Technology, Tokyo, Japan, 2011.

Academic Societies & Scientific Organizations:• Peru Engineering Association (CIP)

Journal of Disaster Research Vol.8 No.2, 2013

Cyclic Behavior of Low Ductility Walls Considering Perpendicular Action

Name:

Name:

Patricia Gibu

Lourdes Cardenas Paredes

Affiliation:

Affiliation:

Associate Researcher, Laboratory of Structures,
CISMID
Associate Professor, Faculty of Civil Engineering, National University of Engineering (UNI)

Associate Researcher, Laboratory of Structures,
CISMID, National University of Engineering

Address:

Address:

Jr. Tumbes 255, Barranco, Lima 04, Lima, Peru

Enrique Villar Street 618, Sta Beatriz, Lima 01, Lima, Peru

Brief Career:

Brief Career:

1989 Undergraduate Course, Faculty of Civil Engineering, National
University of Engineering (UNI), Lima, Peru
1999 Master Course, Graduate School of Science & Technology, Nihon
University, Japan
2000 Assistant Teacher, Faculty of Civil Engineering, National Universityof Engineering (UNI) and Associate Researcher, Lab. Structures, CISMID
2005-2012 Chief, Laboratory of Structures, CISMID

2006 Undergraduate Course, Faculty of Civil Engineering, Ricardo Palma
University, Lima, Peru
2009 Master Course, National Graduate Institute for Policy
Studies/International Institute of Seismology and Earthquake Engineering,Japan
ATM Fellow 2010, Study Leave, IABSE

Academic Societies & Scientific Organizations:• L. Cardenas and C. Zavala, “Structural Vulnerability Assessment ofComercio Hotel,” URP, 2006.
• L. Cardenas and T. Mukai, “Evaluation of Structural Performance for
Confined Masonry Walls Retrofitted with Wire Mesh and with Disposable
Fiber Mats,” IISEE master program, 2009.
• C. Zavala, L. Cardenas, J. Taira, and F. Rios, “Report of Basic Data on
Non-Engineered Buildings Developed by The Japan Peru Center for
Earthquake Engineering Research and Disaster Mitigation of the National
University of Engineering,” CISMID-UNI, in collaboration with GRIPSTokyo, Japan, March 2010.

• Peru Engineering Association (CIP)

Name:
Luis Martin Lavado Duránd

Selected Publications:

Academic Societies & Scientific Organizations:
Affiliation:
Research Assistant, Structures Laboratory, CISMID, National University of Engineering (UNI)• Japan-Peru Center for Earthquake Engineering and Disaster Mitigation(CISMID-UNI)• Peru Engineering Association (CIP)

Address:
210 Tupac Amaru Avenue, Rimac, Lima, Peru

Name:

Brief Career:

Luis Ceferino Rojas

2000 Joined Structures Laboratory, CISMID, National University ofEngineering
2001 Internship BRI, Tsukuba, Japan
2010 Internship Applied Science University, Regensburg, Germany

Name:

Affiliation:
Research Assistant, CISMID

Address:
Mz F Lte 6 Los Pinos St. Ate-Vitarte, Lima, Peru

Jenny Taira

Brief Career:Affiliation:2011 Structural Design Assistant, CESEL Corp.
2010 Joined CIMID-UNI

Research Assistant, Structural Laboratory, CISMID

Selected Publications:• “Cyclic behavior of low ductility walls considering perpendicular action”(co-author).

Academic Societies & Scientific Organizations:• Japan-Peru Center for Earthquake Engineering and Disaster Mitigation(CISMID-UNI)

Address:
Av. Tupac Amaru 1150, Lima 25, Peru

Brief Career:
2006 Joined Structural Laboratory, CISMID
2008-2009 Master Degree in Earthquake Engineering, Building ResearchInstitute (BRI)
2012 Training Course in Disaster Risk Reduction, Kobe University

Selected Publications:• “Seismic Performance of Reinforced Concrete Wall-System with
Electro-Welded Mesh,” Master Degree thesis, 2009.

Journal of Disaster Research Vol.8 No.2, 2013319