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Proceedings of the 3
rd
International Conference on Civil Engineering for Sustainable Development
(ICCESD 2016), 12~14 February 2016, KUET, Khulna, Bangladesh (ISBN: 978-984-34-0265-3)
ICCESD 2016 721
LESSONS LEARNED FROM NEPAL EARTHQUAKE (M 7.8): DAMAGE
BEHAVIOUR OF BUILDINGS IN BANGLADESH
M.R. Awall
1
, M.A. Rahman
*2
, K.M.S. Uddin
3
1
Associate Professor, RUET, Rajshahi, 6204, Bangladesh, e-mail: robi95@gmail.com
2
B.Sc. in Civil Engineer, RUET, Bangladesh, e-mail: shuvo10ruet@gmail.com
3
B.Sc. in Civil Engineer, RUET, Bangladesh, e-mail: polashkhan107@gmail.com
ABSTRACT
In the last few years several devastating earthquakes has occurred in different part of the world. In the year
2015 a major earthquake has occurred in Nepal (M 7.8), caused a great loss of life and property. It also
affected the neighboring country like Bangladesh and India. This review paper represents the effect of Nepal
earthquake in buildings of Bangladesh. The buildings designed and constructed by taking proper earthquake
resistant measures have helped to minimize the damage. Some measures for designing earthquake resistant
buildings are also discussed in this paper. The significance of this work is to reduce the earthquake damage by
introducing some resistive measures in the design of buildings.
Keywords: Nepal earthquake, Damages, Earthquake resistant measures
1. INTRODUCTION
In, recent past major earthquake has not happened in Bangladesh. But Bangladesh is one of the most tectonically
active regions in the world. It is situated in the meeting point of the Indian tectonic plate, the Eurasian tectonic
plate and the Burmese tectonic plate (American Museum of Natural History, 2013). The Indian plate is moving
northwest gradually and it is slowly colliding with the Eurasian plate. As a result the Himalayas is rising. Along
this border active faults are notiched. The northern part of Bangladesh is enclosed by Dauki fault of length 300
km. Shilling Plateau fault system is the main risk for Bangladesh because it is closest to Bangladesh. On the
other hand in the east the Burmese plate pushes against the Indian plate to the west. The faults in the northern
and western part of Bangladesh can generate huge earthquake. The devastating 2004 earthquake and tsunami in
Sumatra occurred along the boundary between the Indian and Burmese plates (American Museum of Natural
History, 2013).
In different time terrible earthquakes occurred in Bangladesh. The first recorded earthquake in Bangladesh was
occurred in the year of 1548. Sylhet and Chittagong was affected by this earthquake. The next earthquake
occurred in 1642. Sylhet district was damaged terribly. In 1963 a severe earthquake occurred in ASSAM.
Another earthquake occurred in 2
nd
April, 1762. It caused a permanent submergence of 155.40 sq km area near
Chittagong (Institute of Earthquake Engineering Research, CUET, 2012). This earthquake seriously affected
Dhaka and along the eastern bank of the Meghna as far as Chittagong. In Dhaka about 500 persons lost their
lives, the rivers and Jheels were agitated and raised high above their usual levels. Another earthquake was
occurred in 1775 around April 10.
In 1812 earthquake occurred in many places of Bangladesh. Sylhet was
proved to be mostly affected. Cachar earthquake was occurred in 1869. Another earthquake of magnitude 7.5
occurred on 10 January, 1889 in Jaintia Hills.The great Indian earthquake of magnitude 8.7 was occurred in
1897. In 18 July, 1918 Srimangal earthquake was occurred. Its magnitude was 7.6 and epicenter was at
Srimangal. Dhubri earthquake of magnitude 7.1 was occurred at Dhubri, Assam in 1930 (Institute of Earthquake
Engineering Research, CUET, 2012). Eastern part of Rangpur district was affected by this earthquake. Another
earthquake of magnitude 8.4 was occurred at Assam, India. It took place on 15 August, 1950. In 1997 an
earthquake of magnitude 6.0 was occurred in Chittagong. 1999 and 2003 an earthquake of magnitude 5.2 and
5.1 respectively were occurred in Maheskhali Island and Rangamati. Recently a terrible earthquake was
occurred in Nepal. It occurred at 11:56 NST on 25 April 2015. This earthquake affected Nepal, India,
Bangladesh and China (Wikipedia, the free encyclopedia, 2015). It causes a great damage to life and property of
the people of this area. The prediction of scientists is that a major earthquake closer to Bangladesh is only a
matter of time (American Museum of Natural History, 2013).
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International Conference on Civil Engineering for Sustainable Development (ICCESD 2016)
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Figure 1: Earthquake zoning map of Bangladesh (Surraz et.al, 2015)
Based on seismic susceptibility Bangladesh has been divided into four zones like Zone-1, Zone-2, Zone-3 and
Zone-4. The north-eastern region of Bangladesh is considered as Zone-4 with the value of basic seismic co-
efficient z=0.36. This zone has high seismic risk. The district Rangpur, Tangail, Narshindi etc. are situated in
Zone-3. The basic seismic co-efficient of this zone is z=0.28. The central part of Bangladesh is considered as
Zone-2. The capital of Bangladesh, Dhaka is in this zone. The basic seismic co-efficient of this zone is z=0.20.
The south western part of Bangladesh is considered as Zone-1. This zone is comparatively safe zone. The basic
seismic co-efficient of this zone is z=0.12 (Surraz et.al, 2015). Figure 1 represents the earthquake zoning map of
Bangladesh.
2. NEPAL EARTHQUAKE
Recently a terrible earthquake has occurred in Nepal on 25
th
April 2015 at 11:56 NST with a magnitude of 7.8
(USGS, 2015). The epicenter was in the east of the Lamjung district located at a distance of 80 km from the
capital of Nepal and its hypocenter was located at a depth of approximately 8.2 km (5.1 mi) (Wikipedia, the free
encyclopedia, 2015). Figure 2 shows the location of epicentre of the Nepal earthquake. After the 1934 Nepal–
Bihar earthquake, it was the worst natural disaster in Nepal. About 8900 people was died in Nepal (“Massive
Damage”, 2015). Thousands of people have lost their home. Their villages were flattened. Centuries-old
buildings were destroyed at UNESCO World Heritage sites in the Kathmandu Valley, including some at the
Kathmandu Durbar Square, the Patan Durbar Squar, the Bhaktapur Durbar Square, the Changu Narayan Temple
and the Swayambhunath Stupa (Wikipedia, the free encyclopedia, 2015). More than 100 aftershocks were
recorded in Nepal. They have occurred within 15-20 minute interval. Among these shocks one shock reached
the magnitude of 6.7 on April 26 at 12:54:08 NST (Wikipedia, the free encyclopedia, 2015). Landslides have
also occurred in different part of the Nepal. This earthquake also affected India, Bangladesh and China. The
epicentre of the earthquake was located at a distance 745 km from the capital of Bangladesh. Figure 3 show the
relative position of Bangladesh and Nepal with respect to epicenter respectively.
Figure 2: Location of epicentre of the Nepal earthquake (Wikipedia, the free encyclopedia, 2015)
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International Conference on Civil Engineering for Sustainable Development (ICCESD 2016)
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Figure 3: Relative position of Bangladesh and Nepal with respect to epicenter (USGS, 2015)
3. EFFECT OF NEPAL EARTHQUAKE IN BANGLADESH
Bangladesh was affected by the Nepal earthquake. Most of the district of Bangladesh felt the shake of the Nepal
earthquake 2015. This earthquake created a great panic amongst the people of Bangladesh. In different places
buildings were cracked. The Ponds and Jheels were agitated and raised high above their usual levels.
In Bongsal, Dhaka a six storied building was tilted due to this earthquake as shown in Fig. 4 (“Losses of
Earthquake”, 2015). Due to vibration of earthquake differential settlement occurred in the soil layer below the
structure. As a result the building was tilted.
In Dhaka another building was affected by earthquake. Crack was formed in the wall of staircase of this
Building. In Bogura wall of a primary school was cracked and boundary wall of a hospital was collapsed as
shown in Fig. 5 (“Losses of Earthquake”, 2015). The primary cause of these types of failure is the use of solid
brick. Solid brick walls are vulnarable to earthquake. They can be supported only by sand and cement mortar. In
solid brick wall there is no way to provide rebar in horizontal or vertical direction for stiffening it. So due to
heavy shake of earthquake it cracks and collepses. Beside this due to use of solid bricks the total weight of
building increases which adversely affect the earthquake resisting capacity of the building structure.
Figure 4: Tilted Building in Bongsal (“Losses of Earthquake”, 2015)
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.
Figure 5: Cracked Staircase, Cracked wall of Primary school & Collasped boundary wall (“Losses of
Earthquake”, 2015)
In Khulna district, the Khulna City Corporation Women college Building was terribly damaged. Beams and
columns of this building were cracked seriously. A part of this Building was tilted and crack was formed along
the beams and columns of the inner face of the building. Cracked beam-column joint is shown in Fig. 6. It was
cracked during earthquake due to presence of eccentric beam-column joint. From Fig. 6 it can be seen that the
beam was not located centrally with the column. As a result eccentricity was developed at the joint and the joint
cracks during earthquake. A cracked column with an uncracked beam is shown in Fig. 7. In this case the
stiffness of the beam was more than the stiffness of the column. As a result cracking of column has occurred
during earthquake due to formation of plastic hinge in the column. If the column of the building frame was
made stronger than the beam then the energy of earthquake can be more uniformly distributed throughout the
building. In this system plastic hinge generally form in the beam while the column remains elastic. As a result
the structure become partially damaged which may be repairable. The tilted part of the Khulna City Corporation
Women College building is shown in Fig. 8. This part was tilted due to differential settlement in the soil layer.
Cracks were developed in different beams and columns of this tilted building.
Glass of a commercial building was broken in Shaheb Bazar, Rajshahi. The affected building is shown in Fig. 9.
The building is face to the west. Vibration of earthquake was in north-south direction. Due to this vibration
tension governs on one side of the structure and compression governs on the opposite side of the structure. But
the less stiff glass used in this building cannot stand with this tension and compression phenomenon. As a result
it broke. It is seen that annealed and heat strengthened laminated glass exhibited higher rasistance to glass fall
out during earthquake (Behr, 2001). So for better performance during earthquake these types of glass should be
used.
Figure 6: Cracked Beam-Column joint Figure 7: Cracked Column with uncracked beam
Cracked
Column
Beam
Crack
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Figure 8: Cracks of tilted Building Figure 9: Broken glass of the Building
Figure 10: Cracked beam, wall joint and displaced door of the affected building
Figure 11: Elevation of the Building
In Rajshahi another 6 storied building was affected by the earthquake. Cracks were formed in different beams,
walls and at the joint of wall with beam and columns. Cracked portion of the building is shown in Fig. 10. The
frames of door and window of this building were displaced from their original position by an amount 1/2
//
. The
elevation of the building is as shown in Fig. 11. From this figure, it can be seen that the building has vertical
irregularity. The left side of the building is higher than the right side. So, the mass of left portion of the building
is greater than the right portion. Again, the inertia force, generated during the earthquake is proportional to the
mass. So, the inertia force generated due to tilting of building in the left direction is greater than due to tilting of
building in the right direction. As a result displacement of building in the left direction is more. This uneven
displacement of structure due to shake of earthquake was resulted in cracks in different components of the
building.
The largest shopping center of Bangladesh “Jamuna Future Park” was also affected by the earthquake. Crack
was formed at different Beam-Column joints of this building as shown in Fig. 12. From this figure it can be seen
that the beam was not located centrally with column. As a result some eccentricity was induced in this joint. Due
to this eccentricity cracking of beam-column joint occur during earthquake.
The example of the damages of Fig. 6 to Fig. 12 were collected from different locations in Bangladesh.
Broken glass
of the building
Cracks in the
Beam-Column joint
Cracks in the beam
of tilted Building
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(a) (b) (c)
Figure 12: Cracked Beam-Column joints of Jamuna Future Park Shopping Center
Figure 13: Regular plans Figure 14: Irregular plans
Figure 15: Orientation of column in plan
4. POSSIBLE WAY TO MITIGATE EARTHQUAKE DAMAGES
Earthquake damages a huge amount of our life and property. It is not possible to stop earthquake or to predict
about the time of occurrence of earthquake. But it is possible to reduce the losses of earthquake by adopting
some preventive measures in the design of different structures. Some important measures are-
4.1 Avoiding Irregular Plan of Building
The plan of building should be regular to make it better against earthquake. H, I, O shaped plans as shown in
Fig. 13 are regarded as good plan. These plans are symetric with respect to any direction. On the other hand L,
C, T shaped plans as shown in Fig. 14 are regarded as bad plan (Mollick, 2013). These plans are not symetric.
Displacement of these type of plans is not same in both direction when subjected to earthquake shaking. As a
result the structure become imbalanced. Buildings with irregular plan have been observed to be susceptible to
significantly larger deformation and damages than building with regular plan when subjected to earthquake
motion.
4.2 More Stiff Column and Less Stiff Beam
By using strong column and weak beam energy of earthquake can be more uniformly distributed throughout the
building. In this system plastic hinge generally form in the beam while the column remains elastic. As a result
the structure become partially damaged which may be repairable. On the other hand if strong beam and weak
column is used then there is possibility of
forming plastic hinge in the columns of a lower storey. Due to this
total structure will collapse and causes a great loss of life and property (Smith, 1988).
4.3 Orientation of Column
Orientation of column in a plan of a building is very important. It will affect the stiffness of the building.
Consider the plan as shown in Fig. 15. Moment of inertia of the building is greater in east-west direction. So the
building is weaker in north-south direction and stronger in east-west direction. Assume the column section of
h
b
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International Conference on Civil Engineering for Sustainable Development (ICCESD 2016)
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width b and depth h. Here h>b. If column is oriented in north-south direction then the moment of inertia in this
direction will be /12. On the other hand if column is oriented in east-west direction then the moment of
inertia in north-south direction will be /12. Here /12> /12. For better stiffness in north-south direction
column should be oriented in north-south direction (Mollick, 2013).
4.4 Avoiding Flat Plate Design
In recent time flat plate design method become popular over beam-column frame method. But in flat plate
design method total weight of structure become high. During earthquake due to ground shake an internal force is
generated within the building. This force is called the inertia force. This force causes most of the seismic
damages (Lorant, 2012). This inertia force can be expressed by the equation given below-
F(inertia) = Mass(M) X Acceleration(A)
So, the inertia force increases with the increase of the mass (weight) of the building. In the flat plate design the
weight of the building is more. The inertia force will be more which results in increasing damage during
earthquake. Beside this weak beam-strong column philosophy cannot be applied in the flat plate design. As a
result building frame collapses due to formation of plastic hinge in the columns.
4.5 Use of Hollow Brick Instead of Solid Brick
Solid brick is heavier than hollow brick. So if solid brick is used, the weight of structure will be more. On the
other hand seismic force is proportional to the weight of the structure (Lorant, 2012). So, if we use solid brick
then the seismic force generated on the structure will be high. Beside this in hollow brick there is provision to
provide rebar in horizontal and vertical direction to increase the stiffness of brickwork. As a result the shear
resistance capacity of the brick wall increases (Mollick, 2013).
4.6 Avoiding Eccentric Beam-Column Joint
Eccentric beam-column joint make a building vulnerable to earthquake. Building collapses due to eccentric
beam-column joint during an earthquake. A research report founded that shear
strength of eccentric beam-
column joint is reduced by 40% due to seismic force. This results in the collapse of beam-column joint
(Hirosawa et al., 2000). So, eccentric beam column joint should be avoided. To avoid eccentricity in joint beam
should be connected centrally with the column. Beam-Column joints with and without eccentricity are shown in
Fig. 16.
With eccentricity Without eccentricity
Figure 16: Beam-Column joint with and without eccentricity
(Centre line of Beam and column
do not coincide )
(Centre line of Beam and
column coincide )
Centre line of Beam
Centre line of Column
Column
Beam
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Building with soft Storey Collapse of building due to soft storey
Figure 17: Presence of soft storey in a building and its effect
4.7 Avoiding Presence Of Soft Storey
If any storey of a building has stiffness less than 70% of the stiffnes of the storey immediately above it or less
than 80% of combined stiffness of three stories above, then it is called a soft storey. Presence of soft storey in
the structure will make it vulnerable to earthquake. Due to presence of soft story excessive drift occur in that
story. However, excessive drifts in the story coupled with p-delta effects on the yielded columns make buildings
collapse (Hejazil et al., 2011). Figure 17 shows the presence of soft storey in a building and its effect.
Besides, minimum clear space between two structures should be maintained. If not maintained, hammering will
occur between the structures due to the shake of earthquake and cause damages.
5. CONCLUSION
Earthquake is an unpredictable and unavoidable natural disaster. No one can say when and where it will occur.
The only way to be safe from earthquake is to take necessary precautions. In this review paper the effects of
Nepal Earthquake-2015 on the building structures of Bangladesh are discussed. From the observation it can be
concluded that in Bangladesh several number of buildings are damaged during the Nepal earthquake. Most of
these buildings were built with improper planning and not considering the adequate safety measures in design
which are required incase of earthquake. These damages during earthquake can be minimized by taking some
preventive measures which are also discussed in this paper. An investigation shows that Bangladesh has got a
natural destructive energy which is located 32-km below earth surface in the Indian area but only 250-km away
from the capital city of Bangladesh. This energy may come out any time with a major shaking all over
Bangladesh. So, sufficient measures should be taken to make the existing structures safe against earthquake. An
active interaction between earthquake engineers, structural engineers, seismologist, architects and government
authorities should take place which will greatly help in reducing the building seismic vulnerability. Beside this
training of engineers about earthquake resistant design and construction practices should be imparted on a
continued basis.
REFERENCES
American Museum of Natural History. (2013). Earthquake Risk in Bangladesh. Retrieved from http://
Earthquake risk in Bangladesh, amnh.org/education/Bangladesh, American Museum of Natural History
Institute of Earthquake Engineering Research,CUET. (2012). History of Earthquake in Bangladesh. Retrieved
from http://ieercuet.weebly.com
USGS. (2015). Magnitude 7.8 Earthquake in Nepal & Aftershocks. Retrieved from
http://www.usgs.gov/blogs/features/usgs_top_story/magnitude-7-8-earthquake-in-nepal/
Wikipedia, the free encyclopedia. (2015). April 2015 Nepal Earthquake. Retrieved from http://en.wikipedia.
org/wiki/April_2015_Nepal_earthquake
Massive Damage and Many Displaced persons. (2015, July 28). The AmeriCares. Retrieved from
http://www.americares.org/who-we-are/newsroom/news/americares-responding-to-nepal
earthquake.html?gclid=CNKkh-T2hMgCFRYQjgodWlALVQ
Losses of Earthquake throughout the country. (2015, April 25). The Daily ProthomAlo. Retrieved from
http://www.prothom-alo.com
Mollick, M.A.A. (2013). Assam Earthquake and our Buildings. Paper presented at a seminar in Rajshahi
University of Engineering & Technology auditorium, Rajshahi, Bangladesh, 24 August 2013.
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Lorant, G. (2012, March 15). Sesmic Design Principles. Retrieved from http://www.wbdg.
org/resources/seismic_design.php
Hirosawa, M., Akiyama, T., Kondo, T. & Zhou, J. (2000). Damage to Beam-to-Column Joint Panels of R/C
Buildings caused by the 1995 Hyogo-ken Nanbu Earthquake and the Analysis. Paper presented at 12th
World Conference on Earthquake Engineering, Auckland, NewZeland, 2000.
Hejazil, F., Jilani, S., Noorzaei, J., Chiengl, C.Y., Jaafar, M.S. & Ali, A.A.A. (2011). Effect of soft story on
Structural Response of High Rise Buildings. IOP science. Retrieved from
http://iopscience.iop.org/article/10.1088/1757-
899X/17/1/012034/pdf;jsessionid=97422215F9B176F774936B0C4C479FFF.c1
Behr, R.A. (2001). Architectural Glass for Earthquake-resistant Buildings. Retrieved from www.glassfiles.com
Surraz, A., Ali, M.K., Das, D.C. (2015). Seismic Vulnerability Assessment of Existing Building Stocks at
Chandgaon in Chittagong city, Bangladesh. American Journal of Civil Engineering 2015, 3(1), 1-8.
http://www.sciencepublishinggroup.com/j/ajce
Smith, J.W. (1988). Vibration of structures: Application in civil engineering design (1
st
ed., chap. 6, pp. 190-
191). New York: CHAPMAN AND HALL.