A Simplified Method for Preliminary Seismic Vulnerability Assessment of Existing Building in Kundasang, Sabah, Malaysia

Abstract

A simplified method for preliminary seismic vulnerability assessment of existing building in particular area of Kundasang, Sabah Malaysia region is proposed. The surveys are mainly focused on building inventory such as identifying the building occupancy, building type and the storey number of buildings for study area. Rapid Visual Screening (RVS) can be effectively used to evaluate the vulnerability of large number of buildings for study area with less computational effort. The data collection form of the Federal Emergency Management Agency (FEMA 154) for RVS was gathered for this purpose. The objective of this study is to assess the vulnerable building that tendency to be further detailed analysis by the calculation of score in RVS method. Pre-assessment towards seismic vulnerability of every individual building in particular area has been assessed and the information of buildings in study region consist residential, industrial, government, school building occupancies were recorded and spatially analyzed using Geographical Information System (GIS) framework. Buildings in Kundasang are considered as less further evaluation (34%) which need have detailed analysis by modeling the structure, while another 66% considered as safe building based on rapid visual final score.

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72:3 (2015) 1–7 | www.jurnalteknologi.utm.my | eISSN 2180–3722 |
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Jurnal
Teknologi
A Simplified Method for Preliminary Seismic Vulnerability Assessment of
Existing Building in Kundasang, Sabah, Malaysia
M.Ghafar, N. Ramly, M. Alel*, Azlan Adnan, Edy Tonnizam Mohamad, M.Z.M.Yunus
Faculty of Civil Engineering, Universiti Teknologi Malaysia, 81310 UTM Johor Bahru, Johor Malaysia
*Corresponding author: alel@utm.my
Article history
Received: 17 August 2014
Received in revised form:
17 November 2014
Accepted: 24 December 2014
Graphical abstract
Abstract
A simplified method for preliminary seismic vulnerability assessment of existing building in particular
area of Kundasang, Sabah Malaysia region is proposed. The surveys are mainly focused on building
inventory such as identifying the building occupancy, building type and the storey number of buildings
for study area. Rapid Visual Screening (RVS) can be effectively used to evaluate the vulnerability of
large number of buildings for study area with less computational effort. The data collection form of the
Federal Emergency Management Agency (FEMA 154) for RVS was gathered for this purpose. The
objective of this study is to assess the vulnerable building that tendency to be further detailed analysis by
the calculation of score in RVS method. Pre-assessment towards seismic vulnerability of every individual
building in particular area has been assessed and the information of buildings in study region consist
residential, industrial, government, school building occupancies were recorded and spatially analyzed
using Geographical Information System (GIS) framework. Buildings in Kundasang are considered as less
further evaluation (34%) which need have detailed analysis by modeling the structure, while another 66%
considered as safe building based on rapid visual final score.
Keywords: Vulnerability assessment, Rapid Visual Screening, GIS.
Abstrak
Satu kaedah mudah bagi pra-penilaian seismik bangunan di kawasan tertentu wilayah Kundasang, Sabah,
Malaysia.. Kaedah tinjauan ini terutamanya tertumpu kepada membina inventori bangunan seperti
mengenal pasti penghunian bangunan, jenis bangunan dan bilangan tingkat bangunan bagi kawasan
kajian. Pemeriksaan Visual Pesat (RVS) boleh digunakan dengan berkesan bagi menilai kelemahan
sebilangan besar bangunan bagi kawasan tertentu dengan kaedah yang kurang pengiraan. Objektif kajian
ini adalah untuk menilai bangunan berpontesnsi kecenderungan untuk dianalisis lebih terperinci dengan
pengiraan skor dalam kaedah RVS . Bangunan di Kundasang dianggap sebagai kurang (34% ) yang
memerlukan analisis terperinci oleh pemodelan struktur, manakala selebihnya lagi dianggap bangunan
selamat 66 % berdasarkan faktor oleh seni bina. Semua pangkalan data bangunan direkodkan dan
dianalisis dengan menggunakan Sistem Maklumat Geografi rangka kerja (GIS).
Kata Kunci: Kelemahan bangunan, Penilaian Visual Rapid (RVS), GIS.
© 2015 Penerbit UTM Press. All rights reserved.
1.0 INTRODUCTION
Malaysia has been categorized under low seismicity area.
Consequently, earthquake resistant design has not been given
as emphasis until a decade ago when the Malaysian
lawmakers were briefed by Meteorological Department
(MMD), in 2002, on the distant of shock waves of the 2001
Gujarat earthquake, which travelled 600 km from its epicenter
to rock and cause devastation to many cities in India [1].
Since 2005, the government of Malaysia has taken various
efforts, through the Ministry of Science, Technology and
Innovation (MOSTI), to assess the risk associated with
potential earthquake events. A report from MMD, a weak
earthquake has occurred with magnitude 4.8 Richter scale in
Pekan Ranau, Sabah at 7:35pm on 01 February 2014.The
earthquake epicenter is located at latitude 6˚10’ N and
longitude 116˚ 45’E, 16 km Northeast of Ranau, Sabah.
Tremors felt near Ranau, Sabah. Most people perceive that
Malaysia is free from life-threatening seismic crisis. In reality,
seismic hazard in Malaysia is irrefutable, with seismic hazard
originating from seismically active neigbouring countries
such as Indonesia and Philippines [2].
In the past, Kundasang region has been jolted by
moderate earthquake events as reported in MMD database.
The study area is located at Kundasang, Sabah, Malaysia. It
lies from latitude 5˚ 58’ N to 6˚ 00’ and longitude from 116˚
33’ E to 116˚ 36’E and the covered area about 22.2 km.
Kundasang owes its moderate seismicity condition to the
active Mensaban and Lobou-Loubo faults zones, which have
brought about earthquake that cause light damages to
infrastructures such as road and bridge [3]. This region has
been identified as a potential site for a future catastrophic
earthquake and has already witnessed seismic events of lower
79
353
44 54
143
44
0
50
100
150
200
250
300
350
400
C3 W1 W2 S3 URM RM1
Building Type
No of Buildings againts Building Type

2 M.Ghafar et al. / Jurnal Teknologi (Sciences & Engineering) 72:3 (2015) 1–7
magnitude in recent past. These earthquakes have
demonstrates that the seismic vulnerability of the building
stocks in the region was primarily responsible for a large
number of human casualties [4]. Most of the buildings in the
region are non-engineered and awareness and knowledge
among the masses is lacking regarding earthquake-resistant
construction technique in areas of high seismic vulnerability.
Inadequate building by law and lenient regulatory regimes
only contribute to the problems. There is a need to assess the
vulnerability of building stocks in such seismically active
area. Due to non-availability of enough building inventory
data for seismic vulnerability assessment, a procedure based
on fieldwork called Rapid Visual Screening (RVS) is found to
be suitable and has been illustrates using Geographical
Information System (GIS) in term of building occupancy [5].
Vulnerability is often represented by the probability of
reaching or exceeding different damage state for a specified
hazard scenario. Vulnerability can be briefly defined as ‘being
prone to or susceptible to damage or injury’ [6]. To determine
vulnerability, a long chain of causes or factors can be
analyzed, and among them, natural, technological, social and
political are the salient factors. The assessment of
vulnerability to estimate the seismic risk requires particular
information on each one of the factors and elements at risk.
All items, like geologic evolution, urban development,
strength of structures and possible collateral effects, have to
be considered carefully to assess as accurately as possible the
seismic vulnerability of a site. Seismic vulnerability can be
measured either qualitatively or quantitatively [7]. The
qualitative measure of assessment can be carried out by
classification of damages to various types of constructions
using different earthquake intensity scales Modified Mercalli
Index (MMI). Another way of making qualitative measures of
vulnerability is in terms of damage states [8]. A specified
ward in Kundasang (Figure 1) was developed as boundary of
study. The inventory data needed for vulnerability assessment
of houses and buildings in study ward were gathered using
simplified form, in order to carry out an extensive survey.
Figure 1 Buildings, main roads and side roads in study ward.
2.0 METHODOLOGY
2.1 Building Inventory
Building Inventory was conducted during the fieldwork.
These include residential, commercial, industrial, religious,
government, emergency, history and education as building
occupancy data. The limitation on building inventory was
carried out only for particular area in Kundasang. Figure 2
shows example of buildings in Kundasang in term of building
occupancy. The data collection was prepared taking into
consideration of five (4) main types of construction practice
within the ward which are Reinforced Concrete (RC), brick,
wood (Wood for housing,W1 and Wood For Commercial use,
W2) and steel (Steel Frame Building,S3) as shown in Table 1.
Figure 3 illustrates the information such are occupancy
classes (Residential) and structure type (W1) required in the
rapid visual form in order to assess vulnerable buildings in
study area. Building databases are stored in Geographical
Information System (GIS) framework. GIS integrates
extremely diverse data and various tool into common
framework for analysis, cooperation and decision making [9].
The development of GIS system involves detailed information
that facilitates disaster preparedness, mitigation, rehabilitation
and reconstruction or even rescues operations [10].

3 M.Ghafar et al. / Jurnal Teknologi (Sciences & Engineering) 72:3 (2015) 1–7
Figure 2 Building occupancy in study ward area in Kundasang, Sabah.
Residential (top left), Education (top right), Government (down left) and
Religious (down right).
Table 1 Description of building types in Kundasang
Category
Building
Type
Description
Reinforcement
Concrete (RC)
C3
Concrete Frame
Brick
RM1
Reinforcement
Masonry
URM
Unreinforcement
Wood
W1
Wood for housing
W2
Wood for commercial
Steel
S3
Steel Frame
Figure 3 Buildings identity in Kundasang ward
2.2 Rapid Visual Screening (RVS)
The Rapid Visual Screening (RVS) method was designed to be
applied without performing any structural calculations. The
procedure utilizes scoring systems that require the trained
evaluator. The inspection, data collection and decision making
processes typically occurs at the building site. The total duration
for the processes was expected to take approximately 20 minutes
for each building based on numerical seismic hazard and
vulnerability score [11].
Detailed seismic vulnerability evaluation is a technically
complex procedure and can only be performed on a limited
number of buildings. Thus, it is very important to use simplified
procedure that can help to rapidly evaluate the vulnerability
profile of different types of buildings, so that the more complex
evaluation procedures can be limited to the most critical
buildings [12] To assess the buildings within the surveyed area,
the RVS method as suggested by Federal Emergency
Management Agency is used [13].
(a)
(b)
Figure 4 Moderate seismicity FEMA 154 form (a) Basic Score
Modifier for rapid visual screening (b). [14]
Basic Structural hazard scores for various building types are
provided in the RVS form. Figure 4(b) demonstrates the
screener modifies the basic structural hazard score by
identifying and circling score modifiers which are then added
(or subtracted) to the basic structural hazard score to arrive at a
final structural score, S. The basic structural hazard score, score
modifiers and the final structural score S, are all related to the
probability of building collapse [15]. The result of the screening
procedure is a final score that may range above the basic score,
with a high score indicating good expected seismic performance
and a low score indicating a potentially hazardous structure.
While the score is related to the estimated probability of major
damage, it is not intended to be a final engineering judgment of
the building, but merely to identify buildings that may be
hazardous and require detailed seismic evaluation. If the score is
2 or less, a detailed evaluation is recommended. On the basis of
detailed evaluation of engineering analysis through detailed
procedures, final determination of seismic adequacy for
rehabilitations can be made.
1.2
SCREENER

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3.0 RESULTS AND DISCUSSION
3.1 Building Occupancy
The areas covered under the survey are located in Kundasang
region. The survey was mainly focused on identifying building
classification, building type, plot size and shape, clear distances
from surrounding structures and basic information of the
building. Digital photographs of each building from at least two
directions were taken. A database was compiled in
Geographical Information System (GIS) attribute table. There
are approximately 717 structures in the surveyed areas of
Kundasang which differ in term of the type of buildings,
occupancy of buildings and number of storey.
Figure 5 Building Occupancy based on Field work III.
Figure 6 Building Type based on Field Work III.
Figure 7 The numbers of building against Building Occupancy based
on fieldwork.
Figure 5 shows the building occupancy in study ward regarding
on latest field work (F III). All the information provided are
illustrated and managed in Geographical Information System
(GIS) attribute table. Figure 6 shows the building occupancy in
study ward regarding on latest field work (F III). All the
information provided are illustrated and managed in GIS
attribute table. The bar chart shown in Figure 7 illustrates the
total number of buildings in term of building occupancy
respectively. Based on bar chart, the highest number of
buildings are in term of occupancy are the residential building
(571) followed by commercial buildings. This is because
Kundasang is categorized as rural area which has tourism and
agriculture as main attraction. Figure 8 shows the relation
between numbers of buildings with building types (such as C3,
W1, W2 S3, URM and RM1) and W1 type is the majority in
Kundasang. The figure indicates that most of Kundasang areas
are populated with villagers while other types of buildings such
as C3 are comprised mainly of school buildings, hotels and
government buildings.
Figure 8 The numbers of building against building type.
Fieldwork F I
Fieldwork F II
Fieldwork F III
0
100
200
300
400
500
600
Residential
Commercial
Industrial
Educational
Government
Religious
History
Emergency
257
75
224
19
35
0
515
84
324 19
356
571
84
324 19
358
Fieldwork F I
Fieldwork F II
Fieldwork F III
79
353
44 54
143
44
0
50
100
150
200
250
300
350
400
C3 W1 W2 S3 URM RM1
Building Type
No of Buildings againts Building
Type

5 M.Ghafar et al. / Jurnal Teknologi (Sciences & Engineering) 72:3 (2015) 1–7
Figure 9 illustrates the number of buildings according to the
number of storey. About 711 (99.2%) of buildings in
Kundasang are categorized as low rise, 5 (0.7%) are mid-rise
buildings of 4-6 storey while only 1 (0.1%) equal or exceed 7
storeys.
.
Figure 9 Relation Between number of buildings and number of storey.
3.2 Rapid Visual Screening Score Sheet, Analysis and Uses
The damage potential can be estimated based on Rapid Visual
Screening (RVS) score as given in Table 2. However, it should
be realized that the actual damage will depend on a number
factors that are not include in RVS procedure. As a result, this
table should only be used as indicative to determine the
necessity of carrying out simplified vulnerability assessment of
buildings.
Table 2 Structural Scores with Damage Potential
RVS Score
Damage Potential
S < 0.3
High probability of Grade 5
damage; Very high probability
of Grade 4 damage
0.3 < S < 0.7
High probability of Grade 4
damage; Very high probability
of Grade 3 damage
0.7 < S < 2.0
High probability of Grade 3
damage; Very high probability
of Grade 2 damage
2.0 < S < 2.5
High probability of Grade 2
damage; Very high probability
of Grade 1 damage
S > 2.5
Probability of Grade 1 damage
Table 3 shows the result of RVS based on type of building
in Kundasang. Most of the buildings in Kundasang are of the
residential type (571, 79.6%), out of which 183 (32%) are
hazardous while 388 (68%) are non-hazardous.
This is followed by commercial type (84, 11.7%), out of which
33 (39.3%) are hazardous while 51 (60.7%) are considered non-
hazardous. Both the residential type and commercial type which
are considered hazardous have a similar characteristic both in
that have vertical irregularities in term of shape. History type of
buildings (6, 75%) shown highest percentage out of which 4
(80%) are hazardous while 1 (20%) considered non-hazardous.
This is because most of the buildings are built with weathered
unreinforced masonry.
Figure 10 demonstrates the RVS result using GIS based
tool to locate the building which require further investigation.
The result obtained from RVS shows the location of buildings
that need further investigation, for which based on Table 10, the
total structural score less than 2 (S< 2) in Kundasang area is
lower (34%) than no need further investigation which is 66%
that score exceeding 2.5 (S>2.5). Figure 11(a) provides the
number and percentage of hazardous and non-hazardous in
study area respectively while figure 11(b) shows the
composition of the hazardous buildings. About 183 (75.6%)
considered hazardous buildings which is influenced by close
proximity to the hill sides followed by commercial buildings
(33, 13.6%), education buildings (10, 4.13%), government
buildings (5, 2.1%), emergency buildings (6, 2.5%), History
buildings (4, 1.7%), Industrial buildings (1, 0.4%), Religious
buildings (0, 0%)
0
100
200
300
400
500
600
700
800
1-3 4-6
≥7
711
51
Distribution according to Number
of Storey

6 M.Ghafar et al. / Jurnal Teknologi (Sciences & Engineering) 72:3 (2015) 1–7
Table 3 Cumulative results of buildings from rapid visual screening
Building Occupancy
Number of Buildings
Percentage Buildings per Area
Number of Detailed Evaluation
Buildings
(%)
YES
(Hazardous)
NO
(Non-
Hazardous)
Residential
571
79.6
183
388
Commercial
84
11.7
33
51
Educational
24
3.3
10
14
Government
19
2.6
5
14
Emergency
8
1.1
6
2
History
5
0.7
4
1
Industrial
3
0.4
1
2
Religious
3
0.4
0
3
TOTAL
717
100
242
475
Figure 10 Map of buildings detailed evaluation based on RVS.
(a) (b)
Figure 11 Number and percentage of hazardous and non-hazardous building respectively (a) Composition of the hazardous building in Kundasang (b)
183
33
10 5
6
41YES (Hazardous)
Residential
Commercial
Educational
Government
Emergency
History
Industrial
242, 34%
475, 66%
Number of
Detailed
Evaluation
Buildings YES
(Hazardous)
Number of
Detailed
Evaluation
Buildings NO
(Non-Hazardous)

7 M.Ghafar et al. / Jurnal Teknologi (Sciences & Engineering) 72:3 (2015) 1–7
4.0 CONCLUSION AND RECOMMENDATION
The identification of seismically vulnerable of buildings is
necessary first step in developing effective disaster mitigation
programs for the country. This study has shown that most of
the residential buildings in Kundasang have low vulnerability
level due to earthquake impact. Rapid Visual Screening
(RVS) method is one of the effective building assessments
tools, owing to its analyzing speed, user-friendliness, and low
cost. From the assessment by RVS method, the structure score
was produced based on five main aspects, namely the seismic
region type of soil, type of building, building classification,
vertical and plan irregularity. Geographical Information
System (GIS) integrates extremely diverse data and various
tools into a common framework for analysis, cooperation and
decision making. The development of GIS system involves
detailed information that facilitates disaster preparedness,
mitigation, rehabilitation and reconstruction or even rescues
operations. 34% of the buildings score lower than 2 (S<2)
indicate detailed analysis needed for further evaluation, while
another 66% of building in study ward can be marked as safe
buildings because score more than 2.5 (S>2.5) that show the
probability of grade 1 damage is slight damage. The low
numbers of building needed to be further analyzed show that
the buildings in Kundasang area tend to collapse when
subjected to earthquake excitation. The structures that needed
to be further evaluated have to be modeled in structural
analysis software to define vulnerable target element of
individual buildings instead of able to simulate earthquake
scenario.
Acknowledgement
The work was financially supported by Ministry of Science
and Technology of Malaysia, MOSTI (Grant No.Science
Fund 4S021).
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