Seismic Survey and Condition Assessment of School Buildings ...

Seismic Survey and Condition Assessment of School
Buildings
(Case Study Done in the Eastern Province, Sri Lanka)
H.A.D.S.Buddika,
Department of Civil Engineering, University of Peradeniya, Sri Lanka
samithbuddika@gmail.com
Ranjith Dissanayke
Department of Civil Engineering, University of Peradeniya, Sri Lanka
ranjith@civil.pdn.ac.lk
Abstract
Major economic consequences and losses of lives are evident in recent Tsunami tidal waves that
ravaged several countries in the Indian Ocean Rim on December 26, 2004. Although considered a
moderate seismic region, in Sri Lanka, the 2004 Tsunami claimed over 38,000 lives and investment
need for post reconstruction strategy amounted to $2,089Mn. Schools are playing vital role in every
community. Disaster safe schools must be recognized as a basic human right. This statement is easy to
make but difficult to accomplish Therefore, it is the high time to investigate the disaster vulnerability
of important structures such as schools to withstand the future natural disasters.
This paper summarizes the outcomes of seismic vulnerability assessment procedure carried out on
schools in Eastern Province, Sri Lanka. The typical structural deficiencies found during the
investigation are summarized in this paper. The main aim of this work is to identify the existing
seismic vulnerable conditions in the school buildings, in order to establish detail investigation
procedure to minimize the damages to withstand future disasters.
Keywords: future disasters, rapid Visual Screening, structural deficiencies, vulnerability Assessment

1. Introduction
Schools are playing vital role in every community. The public school network in Sri Lanka is vast,
with about 4.2 million children enrolled in over 9,790 public schools around the country. These
schools contain a teaching force about 2 lacks [1] .Seismically safe schools must be recognized as a
basic human right. This statement is easy to make but difficult to accomplish. Government officials
and community stakeholders are accountable and morally responsible for acknowledging the necessity
to improve seismic safety in schools and to act upon that knowledge. Forging alliances between the
many groups involved in school administration and government can be an initial step towards
significant safety improvements. These alliances can provide a multi-disciplinary approach to
problem-solving, and bring added capacity and energy to accomplishing the daunting tasks of seismic
assessment and reconstruction [1].
Even though considered as a non-seismic region, Sri Lanka would expect maximum ground
acceleration of 0.3g [2]. Recent catastrophic natural hazard, 2004 Tsunami claimed over 38,000 lives
and investment need for post reconstruction strategy amounted to more than $2 billion in Sri Lanka.
Therefore, it is the high time to prepare against future disasters because repair and reconstruction of
school buildings are difficult and expensive after earthquake, when government resources are restrain.
Figure1: Tsunami memorial in school
Figure 2: Memories after period of one year
Those responsible for school safety must understand and manage these risks, particularly those risks
that threaten the lives of students, teachers, and staff. Earthquake risk is the product of hazard
exposure and building vulnerability, as shown in the following equation: [5]
RISK = HAZARD x VULNERABILITY x EXPOSURE

2. Seismic risk assessment Method
The various methods for the assessment of the vulnerability of buildings differ in expenditure and
precision. The type of method chosen depends on the objective of the assessment but also on the
availability of data and technology. The table 01 shows the Methods for the assessment of the
vulnerability of buildings [7].
Table 01: Methods for the assessment of the vulnerability of buildings
Total 30 schools (more than 400 buildings) were instigated with rapid visual screening procedure.
Since, Sri Lanka does not have local guidelines to do the visual screening; a novel screening format
was developed in order to cope with local conditions. This paper will highlight the structural
deviancies identified in the survey only. However, important details such as number of students, work
force and previous disaster were recorded for further research purposes.
3. Results and Discussion
The type of building identified during the investigation procedure can be categorized as, concrete
frame with unreinforced masonry infill walls, unreinforced masonry structures and etc. It is very
interested to notice that, majority of the buildings (about 70%) are comprised with unreinforced
masonry buildings with compared to reinforced concrete frame buildings that represent 29% of the
total buildings. The figure 3 illustrates the information’s found during the survey in a format of pie
chart. Other than that, most of the school buildings were constructed at the 10-20 years ago which is
now in bad conditions. Even though some buildings are relatively new it is required to further stress
that, these school buildings are vulnerable due to lack of maintenance; therefore some of them have
changed its use to administrative office only. The typical buildings found during the visual
observation procedure are shown in figures 4.

Figure 3: Classification of buildings according to type of construction
Figure 4: Typical single storey and multistory buildings in school
The deficiencies of the school buildings can be summarized under several topics. Firstly, some old
school buildings are of only load bearing masonry without any seismic safety provisions. Therefore,
the gravity load transfer is only through walls. Hence in the case of earthquake, the lateral load will be
transferred through the elements which are masonry (fig.3). As a result of that, the wall could be
cracked from the openings and may lead to collapse of building. In addition to that, in the reinforced
concrete (RC) structures the efficiency of the RC system depends on its beam-column foundation
interaction to transfer the lateral loads from earthquake. None of the school building has been design
in order to with stand lateral loads. It is necessary to further stress that, the joint detailing requires
special confinement to accomplished ductile mode of failure. The detailing have to be in such a way
that, failure has to be occurring in the beam not in the column. On the other word, strong column-weal
beam concept. The existing cracks in the main load bearing elements such as columns (fig.4) can be
vulnerable during earthquakes. Since, the structure is already crack its load bearing capacity
drastically goes down and building can fail due to its limited lateral load bearing capacity.

Figure 3: Brick columns in the building
Figure 4: Failure of corner columns
The irregular building configurations were observed in many of buildings. The “L” of the building in
plan was the popular configuration in many of buildings. Due to its irregularity in plane it can
undergo tensional mode of vibration during the earthquakes. Other than that, presences of short
columns were observed at the most of the school buildings. In case of earthquake the short columns
are liable to fail due to high stress concentrations (figure 5).
Figure 5: Short columns in the buildings
Despite of that, the foundation condition is one of important parameter to govern the seismic safety of
buildings. As the evidence found during the investigation procedure it can be conclude that the most
of the buildings possess bad foundation conditions due to scouring. Since the ground condition is
almost a sandy soil, the conditions can be vulnerable during the earthquake action.

Figure 6: Foundation conditions observed in the survey
In addition to the main structural deficiencies, control of fire is very much important after an
earthquake happen. As the evidence from the seismic survey it can be concluded that many of the
buildings are with bad electric installation systems. Therefore, fire can be initiate and spread after
disasters. The following figures show the typical wiring installation system in a school.
Figure 7: Typical electric installation systems found during the survey
The results obtain during the visual observation procedure show that a large number of school
buildings are moderately or highly vulnerable to earthquake loading. The main defective identified
during the study is poor structural conditions such as cracks, reinforced exposures, etc that consist of
68 % of total buildings. Other than that, 44 % of the building posses the week foundation conditions
such as scouring and permanent damages due to various actives. In addition to that, the other
structural defect is the short column problem which not only appears in old constructions but also in
new buildings constructed with no technical assistance consists of 23 % of total buildings. Soft storey
in buildings, structural irregularities were observed as other leading problems in the structural system
of school buildings. The results of the structural classification with respect to type of defects are
summarized in the figure 8.

Figure 8: Structural deficiencies as a percentage of totals
4. Conclusion
In this study total 30 school buildings (more than 400 buildings) were investigated with visual
observation procedure. This methodology shown to be effective capturing the basic features of the
school buildings for a rapid and economical assessment of the seismic vulnerability. From the basic
structural types identified, the unreinforced masonry structures are dominant. Others consist of
reinforced concrete structures and wooden structures. It is very interested to notice that, not only old
buildings but also newly constructed buildings posse’s structural deficiencies. Accordingly, it can be
concluded that, majority of school buildings are posse’s structural deficiencies against seismic loading
conditions. Therefore, it is recommended that, the school buildings need more attention prior to its
construction as well as during maintain in order to overcome such vulnerable conditions.
5. Reference
http://studentlanka.com/alevel/government-schools/
Prof Abayakoon S.B.S., Journal of the geological society of Sri Lanka, vol 6 (1995/96) 65-72, Sri
Lanka.
http://www.preventionweb.net/files/3285_UNISDRAsiaPacificRegional2.pdf
http://eusoils.jrc.ec.europa.eu/esdb_archive/eudasm/asia/lists/clk.htm
Rapid Visual Screening of Buildings for Potential Seismic Hazards, FEMA 154, Edition2, March
2002.

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