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SEISMIC VULNERABILITY ASSESSMENT of
SCHOOL BUILDINGS: GAZA STRIP SCHOOLS as
a CASE STUDY S. M. Shehada 1*, S. Q. Shurrab 2
1*,2 Department of Civil Engineering, Islamic University of Gaza, Gaza Strip, Palestine
Abstract:
This study introduces a new approach for seismic assessment of existing school buildings. The proposed
approach requires minimum human effort as it can be implemented by a small team of technical
construction background. The approach is based on EMS-98 scale in addition to rapid survey of
architectural and structural elements of existing school buildings. The study uses 64 selected public school
buildings sampled from a total of 364 schools in Gaza Strip. The results showed that 50% of the surveyed
schools are classified as Vulnerability class B, while 20 % are classified as Vulnerability Class A. The
results were verified using the ‘probability matrix damage’ approach and showed good satisfying
convergence. The results of the study are beneficial for the responsible parties who are expected to take
appropriate actions related to enhancing seismic performance of Gaza Strip schools against seismic
activities, due to the fact that these school buildings not only host about 450,000 students and teachers,
but also serve as emergency shelters for those who lose their homes as a result of political instabilities in
the region.
Keywords: Damage, Vulnerability, EMS-98, Seismic risk, structural type.
1. Introduction:
School buildings have often collapsed during
earthquakes. The 2001 Bhuj earthquake in India killed
1002 students and teachers, the 2005 Kashmir
earthquake in Pakistan killed about 19,000 children,
most of them in collapses of school buildings, and the
2008 Sichuan, earthquake in China destroyed about
6,898 schools killing thousands of students and
teachers (López et al., 2008). In Palestine, earthquakes
occur frequently where some Palestinian cities were
damaged during the past hundred years. Seismicity in
Palestine is mainly affected by the geodynamic
processes acting along the Dead Sea Transform. The
Dead Sea Transform is a left-lateral fault between the
Arabia and the Sinai tectonic plates (Al-Dabbeek and
El-Kelani, 2008, Fruend et al., 1968, Garfunkel, 1981,
Ginsburg et al., 1981, Quennell, 1959 and 1983).
Seismic vulnerability is a measure of how susceptible a
building is to damage for a given severity of the ground
shaking (Borzia, B., Pinhob, R. and Crowleya, H.,
2008). The building vulnerability is due to older
building design codes, poor design practices and poor
code enforcement (Solomn and Zheng, 2010 and
Jalayer et al., 2010).A number of procedures have been
outlined in the literature. The simplest and quickest
way, called walk-down survey, requires only
superficial data collected from a brief inspection of the
building. The number of stories, vertical and plan
irregularities, location of the building, age of the
building, its structural system and apparent material and
workmanship quality are typical parameters that are
used. The purpose of rapid evaluation is to identify or
rank highly vulnerable buildings that deserve further
investigation. The screening method is performed
without any structural analysis and takes little time to
complete. Basic structural hazard scores for various * Samir Shihada, Professor at department of Civil Engineering, The Islamic
University of Gaza, Gaza, Palestine, (e-mail: sshihada@iugaza.edu.ps).
Sallam Shurrab, Infrastructure Engineer at Qatar Ministry of Foreign Affairs,
Gaza, Palestine, (e-mail: sallam2005@hotmail.com).
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building types are provided on the Rapid Visual
Screening form (Aftabur and Shajib, 2012). More
refined methods which include detailed analysis and
take more time than Rapid Visual screening are used for
the evaluation of individual buildings only. In addition,
these methods can be used for rapid screening of
hazardous buildings (Grandori, 1982 and Yakut, 2004).
Al-Dabbeekand El-Kelani (2008) carried out a rapid
seismic vulnerability study of three Palestinian refugee
camps in the West Bank, based on EMS, 1998 and
FEMA 310 provisions. The results of the study showed
that very heavy structural and non-structural damages
to buildings in these camps are expected under the
influence of moderate to strong seismic activities. Al-
Dabbeek (2007) studied vulnerability, and expected
seismic performance of buildings in the West Bank.
Seven regions that represent the West Bank were
investigated by collecting information based on site
conditions, regularity and configuration of structural
and architectural elements of buildings, adjacency,
construction material conditions, etc. The collected data
and analysis were determined according to European
Macroseismic scale 1998 (EMS) and calibrated using
Japanese qualitative method. The results showed that
one third of the investigated buildings belong to seismic
vulnerability of class A (heavy damage), whereas about
40 percent of the buildings indicate class B (moderate
damage ( . Lazzali and Farsi (2012) used the European
Macroseismic Scale EMS-98 to define the relationship
between damage and macroseismic intensity to assess
the seismic vulnerability of buildings in Algiers area.
Results lead to the conclusion that Algiers buildings
have an average vulnerability class B. Panahi et al.
(2014) evaluated the seismic vulnerability of school
buildings in Tehran city based on the analytic hierarchy
process (AHP) and geographical information system
(GIS). The results indicated that only in 3 % of the
school buildings in the study area the destruction rate
will be very high and therefore need to be reconstructed.
Sobaih and Nasif (2012) evaluated the seismic
vulnerability of existing reinforced concrete school
buildings in Egypt using a methodology that is based
mainly on questionnaire forms and a computer program
in order to execute the methodology.
In this study, a new approach for seismic assessment of
existing school buildings in Gaza Strip has been
developed, based on European Macroseismic Scale
(EMS-98) scale and available literature and depends
mainly on rapid survey of school building architectural
and structural elements. The importance of this study
stems from the fact that Gaza Strip school buildings not
only host more than 450,000 students and teachers, but
also serve as emergency shelters for those who lose
their homes as a result of political instabilities in the
region.
2. Topology of existing school buildings in
Gaza Strip
There are 364 school buildings in Gaza Strip hosting
about 450,000 students. The distribution amongst the
directorates of Gaza Strip is shown in Table 1. These
schools are mainly administered by the Ministry of
Education and Higher Education (MEHE) and the
United Nations Relief and Works Agency (UNRWA)
and limited number of schools are considered private
schools. Gaza city, being the largest city in Gaza Strip,
holds the largest number of existing school buildings
(135 Buildings),Khan-yonis directorate includes 73
schools, Middle Area directorate includes 52 schools,
North Gaza directorate includes 60 schools and Rafah
directorate includes 44 schools. Figure 1 shows the
distribution of these school buildings in Gaza Strip
education directorates, (MEHE,2012).
Table 1: Student distribution in Gaza Strip
directorates
Directorate MEHE
students
UNRWA
students
Total
number
North Gaza 41,012 40,929 81,941
Gaza 99,435 57,615 157,050
Middle
Area 24,320 44,168 68,488
Khan-yonis 44,670 39,737 84,407
Rafah 20,236 35,156 55,392
Total 229,673 217,605 447,278
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113
Figure 1: Distribution of school buildings in Gaza
Strip directorates
3. School building structural systems:
Gaza Strip school structural systems fall into three
types; concrete block bearing walls, RC building
frames (Ordinary moment frames) and RC moment
resisting frames (Intermediate moment frames).
MEHE Schools
RC Building frames, which represent 78.15 % of
the total number of schools.
Concrete block bearing walls, which represent
17.23 %of the total number of schools.
Precast frames, which represent 4.62 % of the
total number of schools.
UNRWA Schools
RC Building frames which represent 70 % of
the total number of schools.
Concrete block bearing walls which represent 12
% of the total number of schools.
RC moment resisting frames which represent 18
% of the total number of schools.
4. Proposed Approach for Rapid Seismic
Survey of School Buildings
The new proposed approach for seismic evaluation of
existing school buildings is based on the European
Macroseismic Scale (EMS-98) and data collected from
field survey of school buildings. Fifteen structural and
architectural parameters that create vulnerability are
included within the survey forms. The method is
summarized in the following steps.
A. Preparing the field survey forms that take into
account the structural and architectural
parameters, which are listed below
1. Falling hazards (El.01).
2. Adequacy of entrance and distance of staircases (El.02).
3. Vulnerable sites / poor soil condition (El.03).
4. Short columns (El.04).
5. Plan irregularity in general (El.05).
6. Vertical irregularity in general (El.06).
7. Cantilever system (El.07).
8. Seismic joint (El.09).
9. Building construction material (El.10).
10. Seismic design (El.11).
11. Maintenance (El.12).
12. Large windows on one side of the classroom (El.13).
13. Standard building plans with seismic deficiencies (El.14).
14. Vulnerable forms of vernacular construction (El.15).
B. Defining school building names and their locations.
C. Selecting selected school building (64 building over Gaza
Strip), using a GIS software model.
D. In situ survey of school buildings.
E. Organizing and analyzing collected data.
F. Assigning vulnerability classes for each school
separately, according to the defined magnitude levels;
High (H), Medium (M) and Low (L).
G. Defining damage degree for corresponding vulnerability
classes of each surveyed school building.
H. Arranging expected damage grades, according to EMS-
98 scale.
Selection of school building samples for purposes
of field survey
Studying all of (364) existing school buildings in
Gaza Strip requires immense effort and long time.
GIS tool (Desktop Arc GIS software) is used in order
to locate the school building samples in each
directorate of Gaza Strip. A soil texture map
classifies Gaza Strip for six soil texture types (Figure
North Gaza17%
Gaza37%Middle
Area14%
Khanyonis20%
Rafah12%
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114
2); each soil texture is defined in specified terrain
area on Gaza Strip map. Existing school buildings
(MEHE and UNRWA administration) locations are
projected on the soil map. Then, school buildings
which are enclosed in each specific texture terrain
are listed in separate sheets (based on the
intersection between projected soil texture map and
school building locations by adopting a GIS model
as shown in Figure 3.
School buildings considered in the study
As discussed earlier, the selection is based on
building structural system, building age and
founding soil properties. Sixty four schools are
chosen as shown in Figure (4).
Assigning vulnerability classes
According to the Vulnerability Classes shown in
Table 2 (European Macroseismic Scale EMS-98),
most of Gaza Strip schools are considered as
vulnerability classes (B) to (C). For RC frame
buildings without earthquake resistant design (ERD)
and with serious defects (such as soft story, weak
columns, lack of stiffening elements, long or very
long cantilevers with heavy loads at the end, etc.),
vulnerability class (B) or even (A) may be
appropriate. Seismic vulnerability classes used in
EMS-98 scale (A, B, C, D) are assigned for each
school separately according to building structural
system. Rapid survey forms are used to assign
classes of vulnerability (see Table 3 in an appendix).
The analysis of the considered school buildings
provides the following vulnerability classes: 50% of
school buildings are classified as class (B), and
classes (A), (C) and (D) represe nt 20%, 22% and
8% respectively (As shown in Figure 5).
Figure(2) : Classification of soil texture
profile in the Gaza Strip
Figure (3) : Projection of existing school buildings
locations (vertical and horizontal coordinates) on Gaza
Strip soil texture map, using Arc GIS software (ArcGIS
9.3/9.3.1, ESRI Software, 2013)
NorthGaza
directorate
Gazadirecto
rate
Middledirecto
rate
Khanyonis
directorate
Rafahdirecto
rate
MEHE 5 10 5 9 3
UNRWA 7 8 5 7 5
17.5%
30%
14%
26%
12%
02468
101214161820
Nu
mb
er
of
scch
oo
ls
Figure 4: Selected school samples
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115
The information collected from the field survey
sheets is to identify most parameters that affect
identifying the attribution of the vulnerability class
(Adequacy of entrance and distance of staircases,
Short columns, Cantilever system...).The results
show that the most observed element in surveyed
schools are short columns (El.04), cantilever system
(E.07) and soft story (E.08) , (See Fig 6).
Estimate of Damage
The distribution of damage varies from directorate
to another. For each vulnerability class, the
percentages of damage grade for each of the
different degrees of macroseismic intensity is
described. According to many studies (Dabek,
2007), (Kahane, 1988)and (Yankelevsky, 2008),
Palestine could be exposed to strong earthquake
once or twice during each 50 years and the intensity
would be on Modified Mercalli of “VII” and
“VIII”).The distribution of damage degrees (D1 to
D5) for various EMS-98 intensities (V, VI, VII and
VIII) for the school buildings under study are shown
in (Fig. 7, 8and 9).
Table 2: Vulnerability Classes (European
Seismological Commission, 1998)
Class A20%
Class B50%
Class C22%
Class D8%
Vulnerability Classes of Building
Class A
Class B
Class C
Class D
Figure 5: Vulnerability classes for existing school
buildings in Gaza Strip
EL.1, 72.81%
EL.2, 89.69%
EL.3, 94.69%
EL.4, 90.63%
EL.5, 87.34%
EL.6, 85.16%
EL.7, 88.59%
EL.8, 91.09%
EL.9, 51.25%
EL.10, 79.69%
EL.11, 51.25%
EL.12, 83.44%
EL.13, 83.13%
EL.14, 85.00%
EL.15, 85.47%
0.0% 20.0% 40.0% 60.0% 80.0% 100.0%
EL.1
EL.2
EL.3
EL.4
EL.5
EL.6
EL.7
EL.8
EL.9
EL.10
EL.11
EL.12
EL.13
EL.14
EL.15
Figure 6: Fifteen structural and architectural elements
observed in existing school buildings
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116
EMS-98 damage probability matrix
The damage probability matrix is a matrix which
expresses the statistical distribution of the degrees of
damage for a given Macroseismic intensity (Lazzali
and Farsi, 2012). For purpose of convergence,
damage probability is generated for class (B), which
is the most dominant vulnerability class of
investigated existing school building, see Fig (10).
Conclusion:
The proposed approach for assessment existing
school building is based on simple procedure for the
evaluation of vulnerability classes and damage
distribution using a Macroseismic method (EMS-
98).
Based on the results of this study, about 70 % of
Gaza Strip school buildings are highly vulnerable to
seismic risk (categories A and B). Moreover, about
20 % are classified as category C. Therefore,
existing school buildings in Gaza Strip are
vulnerable to severe damages in case of minor
seismic activities. In addition, existing school
buildings in Gaza Strip are highly exposed to
seismic damage (EMS-98 damage grade) at low
grade, where 30.0 % of school building expected to
be classified as degree (2) damage. The most
Intensity (V)Intensity (VI)
Intensity (VII)Intensity (VIII)
0.00%
10.00%
20.00%
5 4 3 2 1
DA
MA
GE
PR
OP
AB
ILIT
Y
Intensity (V)Intensity (VI)
Intensity (VII)Intensity (VIII)
0.00%
20.00%
40.00%
5 4 3 2 1
Da
ma
ge
pro
ba
lity
Figure 7 :Distribution of damage degrees for
Vulnerability class (A)
Intensity (V)
Intensity (VI)
Intensity (VII)
Intensity (VIII)
0.00%
20.00%
40.00%
Da
ma
ge
pro
ba
bilit
y
Figure 8: Distribution of damage degrees for
Vulnerability class (B)
Intensity (V)Intensity (VI)
Intensity (VII)Intensity (VIII)
0.00%
10.00%
20.00%
5 4 3 2 1
Da
ma
ge
pro
ba
bilit
y
Figure 9: Distribution of damage degrees for
Vulnerability class (C)
Figure 10: Damage probability matrix degrees
for Vulnerability class (B)
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117
vulnerable forms of existing school building in Gaza
Strip are short columns, soft storey and adequacy of
entrance and distance of staircases. These forms tend
to increase seismic risk of school building
(Vulnerability).
References:
1- Aftabur, R. and Shajib, U., 2012, Seismic
vulnerability assessment of RC structures:
a review, Int. J Sci. Emerging Tech, 4(4),
171-177.
2- Al-Dabbeek, J. and El-Kelani R., 2008,
Rapid assessment of seismic vulnerability
in Palestinian refugee camps, Journal of
Applied Sciences, 8(8), 1371-1382.
3- Al-Dabbeek, J., 2007, Vulnerability, and
expected seismic performance of buildings
in West Bank, Palestine, The Islamic
University Journal (Series of Natural
Studies and Engineering), 15(1), 193-217.
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vulnerability analysis for large-scale
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Seventh European Conference on
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R., Fernandez N., Dominquez J., Bala T.,
Cornel G., Safina S., and Vielma R., 2008,
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Education (MEHE), 2012, Statistics about
the reality of education sector for
2011/2012, Gaza Strip, Palestine.
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2014, Seismic vulnerability assessement of
school buildings in Tehran city based on
AHP and GIS, Natural Haza
15- rds and Earth System Sciences, 14, 969-
979.
16- Shurrab, S., 2013, Evaluating seismic
performance of existing school buildings in
Gaza Strip, M.Sc. Thesis, Islamic
University of Gaza, Palestine.
17- Sobaih, M. and Nasif, M, 2012, A proposed
methodology for seismic risk evaluation of
existing reinforced school buildings,
HBRC Journal, 8, 204-211.
18- Solomon, T. and Zheng, L., 2010,
Earthquake induced damage classification
for reinforced concrete buildings,
Srtructual Safety, 32(2), 154-164.
19- Quennell, A., 1959, Tectonic of the Dead
Sea Transform, International Geological
congress, Mexico City, 22, 385-405.
20- Quennell, A., 1983, Evolution of the Dead
Sea Transform, A in Proc. 1st Jordanian
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(Editors), Amman, Jordan, 460-482.
21- Yakut, A.,M2004, Preliminary seismic
performance assessment procedure for
existing RC buildings, Engineering
Structures, 26(10), 1447-1461.
22- Yankelevsky. (2008). SEISMIC
ARCHITECTURE AS AN ESSENTIAL
COMPONENT of the Structural Integrity
of Apartment Buildings in Israel. The 14th
World Conference on Earthquake
Engineering (p. 8). Beijing, China:
Technion- Israel institute of Technology.
23- Kahane, Y. (1988). Earthquake Risk and
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Israeli Case. The Geneva Papers on Risk
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for-desktop.
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118
Appendix
Existing School building name: Banat El Khansa' Elem school Banat El Khansa' Elem school
#
Structural/ architecture parameter
Influence Degree
Rapid Field
survey evaluation
Vulnerability Classes Rapid Field
survey evaluation
Vulnerability Classes
A' B' C' D' A' B' C' D'
Structural System Type R.C Frame R.C Frame
1 Falling Hazards (H,M,L) WE,WH
L-WE
sch
oo
l bu
ildin
g is
clo
sed
to
be
clas
sifi
ed a
s (B
') c
lass
Inti
ial
vuln
erab
ilit
y c
lass
as
stru
ctura
l sy
stem
of
exis
ting
sch
oo
l b
uil
din
g, ac
cord
ing
to
Eu
ropea
n S
eism
olo
gic
al M
acro
seis
mic
,
199
8 T
able
(2
)
L-WE
sch
oo
l bu
ildin
g is
clo
sed
to
be
clas
sifi
ed a
s (B
') c
lass
Inti
ial
vuln
erab
ilit
y c
lass
as
stru
ctura
l sy
stem
of
exis
ting
sch
oo
l b
uil
din
g, ac
cord
ing
to
Eu
ropea
n S
eism
olo
gic
al M
acro
seis
mic
,
199
8 T
able
(2
)
2Adequacy of Entrance
(E,V.G,G,B) N.G N.G
3Vulnerable Sites / Poor Soil Condition
(H,M,L) L L
4 Short Columns (H,M,L) H H
5Plan Irregularity, General
(H,M,L) L L
6Vertical irregularity, General
(H,M,L) L L
7 Cantilever System (H,M,L) WE,WH
H H
8 Soft Storey (H,M,L) H H
9 Seismic Joint dis/ Nor - -
10Building Construction Material
(E,V.G,G,B) G G
11 Seismic Design with
/without Without Without
12 Maintenance (E,V.G,G,B) N.G N.G
13
Large Windows on One Side of 18-22% of surface area of Wall
(E,V.G,G,B) N.G N.G
14Standard building plans with seismic deficiencies
(H,M,L) H H
15Vulnerable forms of Vernacular construction
(H,M,L) H H
Table 3: An example of using Rapid survey forms (fifteen structural and architectural elements applied to
two selected existing school buildings)
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