MODIFIED SEISMIC EVALUATION METHOD FOR
REINFORCED CONCRETE BUILDINGS IN
MYANMAR
Way Phyo Linn
MEE12613

Supervisor:

Seitaro TAJIRI

ABSTRACTIn Myanmar, almost all RC buildings have been built without national building codes and seismic
design consideration. Myanmar still does not have proper seismic evaluation methods and regulation
procedures for existing RC buildings. RC structure is a typical and commonly constructed structure ofurban cities in Myanmar. Therefore, developing a Seismic evaluation method for existing RCbuildings is an important issue for earthquake disaster mitigation in Myanmar nowadays. This paper
describes the Seismic Evaluation of existing RC buildings by the Japanese method which is based
upon a performance design concept. A case study of the community center building in Tsukuba city,
Ibaraki Prefecture, Japan and the lecturer house of Sagaing University in Myanmar was conducted tounderstand more clearly about the Japanese Seismic evaluation method. There are three different
levels of screening to find the seismic capacity of RC buildings in the Japanese standard. In this study,
the first and second screening methods were used to evaluate the seismic performance of the Japanesebuilding which had minor damages on the 2011 Great East Japan earthquake and a good correlation
observed is described. After that, this method was applied again to our Myanmar RC building and an
attempt to adopt this method by modifying into a simple one by using the same concept in
combination of the ACI method in evaluation strength is also described. This study was conductedbased upon my strong desire to develop a simple method that is compatible to our structures and ourengineering society. ACI-318 is already familiar for Myanmar engineers. An easy and a familiar
method can be disseminated quickly. Although we have a time limitation, we need a sustainable study
to make a perfect method.

Keywords: Seismic Evaluation, Disaster mitigation
1. INTRODUCTION
The population of Myanmar has considerably increased from 15 million in 1930, at the time of theBago earthquake, to 60 million in 2012. Building typology, constructional material and construction
technology are in transitional phase that is moving from traditional to the modern. In the pastearthquakes, the buildings/houses constructed with traditional construction technology and materialstood even after earthquakes and there were only a few loss of life. However, due to urbanization
process, adaptation of new technology and material in construction of buildings without engineering
input and codal practice may change the scenario and losses may dramatically increase in case of atremendous earthquake in future. Therefore, mitigation measures need to be considered as a national
plan to check and evaluate seismic performance of the buildings before a huge earthquake comesagain.
Public Works, Ministry of Construction, Naypyidaw, Myanmar.
Building Research Institute (BRI), Tsukuba, Japan.

12. METHODOLOGY
In this paper, I focus on the Japanese Evaluation Method according to the 1st English version of the2001 edition for seismic evaluation and seismic retrofit of existing RC buildings by the Japan Building
Disaster Prevention Association. Earthquake resistance is not a function of lateral strength only. theseismic performance evaluation of existing buildings must involve both strength and deformability.
There are three different levels of screening to find the seismic capacity of RC buildings in theJapanese standard. In this study, the first and second screening methods were used to evaluate theseismic performance of the Japanese building which had minor damage on the 2011 Great East Japan
earthquake and a good correlation was observed. After that, this method was applied again to ourMyanmar RC building, the lecturer house from Sagaing University and an attempt to adopt thismethod by modifying into a simple one by using the same concept in combination of the ACI methodin evaluation strength is also described.
Myanmar once being a British colonial country, measuring and weighing with thefoot-pound-second (F.P.S) system is still dominating in our environment although the government
enforces to use the international system (S.I units) nowadays. Most of the people cannot guess or do
not know how weigh does a kilogram or how long is a meter, including the carpenters, masons, skillfullabors, co-workers and even some who are participating in construction industries. Moreover, most of
the Institutes and Universities have been teaching ACI trend to their students and most of theengineers are familiar with ACI method now. That is why we attempt to adopt by modifying somehard parts of strength evaluation by a more familiar ACI method. Thus, an easy and familiar method
can be disseminated quickly.
3. JAPANESE METHOD FOR SEISMIC EVALUATION OF EXISTING RC BUILDINGS
There are three levels of seismic evaluation methods in current Japanese standard guidelines. The first
method is easy and conservative. In the first method, the material strength and contribution of crosssectional areas of vertical members are considered. The second method is more accurate than the firstmethod. In the second method, the ductility or deformation capacity and strength of vertical members
are considered. For the third method, the contribution of the strength and ductility of beams anddiaphragm walls are also considered. The third screening level considers the failure mechanism of thestructures. In all three levels of screening the determination of basic seismic index (E 0) is the same (i.ethe product of F and C).
To know the seismic capacity of buildings, it is necessary to calculate the seismic index of
the structure (IS) first. The seismic index (IS) is an index which represents the seismic performance ofthe structure. The value of IS can also be defined as the value of maximum elastic response shear
coefficient of the story concerned. The seismic performance of the structures becomes higher as thevalue of IS larger. The seismic index of the target structures (IS) is calculated with following basic Eq.
(1) in all three methods. Basic concept is the same for all three methods in seismic evaluation.
(1)=
T
Then, seismic index of the target structure ( ) is compared with seismic demand index oftarget structure with the following equation.
=ZGU

(2)

Ifvalue is larger, the structure is considered to have enough seismic capacity to resist
assumed earthquake motions. The structure is assumed to have some seismic resistance capacity but it
is not enough if the value ofis larger than . The recommended value ofis 0.8 for the firstscreening and 0.6 for the second and third screenings which are based upon the past earthquake
damaged buildings and experiences. After satisfying the above equation, the target building should
also be satisfied by the following Eq. (3) to ensure the minimum story strength. It is observed from thepast earthquakes that the building which has relatively highindex can also suffer severe damage or2

still be vulnerable if the value of CTU x SD index is less than 0.3. Actually, this checking is verifying
the minimum strength of the structure to get a safe seismic performance.

SD

0.3 Z G U

(3)

3.1. First Level Screening Method of Seismic Evaluation
The first screening level screening considers only the vertical members. All columns and walls areconservatively assumed as brittle members. The seismic capacity is calculated based on thecross-sectional area of the vertical members, average shear stress and concrete strength. Thisprocedure is suitable for non-ductile structures with many walls, or structures with no or little ductility.
The vertical elements are divided into three groups depending upon h0/D values of different column
and wall types. The basic seismic index (E0) of the target structure is obtained by using following twoequations. They depend upon the target buildings which have extremely short column or not. Thelarger value would be taken from the Eq.(4) and (5).

E0 E0 n 1CW  1 .CC FWnin 1
C SC   2 .CW   3 .CC FSCni(4)(5)

3.2. Second Level Screening Method of Seismic Evaluation
In the second level, the axial force and reinforcement are considered to calculate the strengths andductility of the vertical members. The vertical elements are classified into five different categories.
The ductility indexes F of all vertical members are grouped into three different groups in maximum. Inthe second level seismic evaluation, shear force at ultimate flexural capacity and ultimate shear
capacity of columns and walls are calculated, and then their results were compared. The effective
strength factor  can be taken from the standard according to their different ductility F. Thecumulative strength index CT of each story can also be calculated by the sum of the strength C withmultiplication of the story shear modification factor (n+1)/(n+i).There are two basic equations in thesecond level screening. Eq.(6) is the ductility- dominant basic seismic index of the structure and Eq.(7)is strength-dominant basic seismic index of the structure.

n 1E12  E 22  E32nin 1E0 C1   j  j C j F1niE0 (6)(7)

The strength index C in the second screening method is the ratio of the ultimate
load-carrying capacity of the vertical members in the story concerned to the weight of the building
including live load for seismic calculation supported by the story concerned. For ultimate lateralload-carrying capacity of the vertical members (Qu), minimum value must be chosen from Qmu andQsu.

CQU
W

(8)

4. MODIFICATION OF JAPANESE METHOD TO AN ADOPTIVE METHOD BYIMPLEMENTATION OF ACI STRENGTH EVALUATIONIn Myanmar, as a British colonial country, measuring and weighing with the foot-pound-second(F.P.S) system is still dominating in our environment and Yangon Technological University or former
R.I.T (Rangoon Institute of Technology), Mandalay Technological University and others have been3

teaching ACI trend to their students and most of the engineers are familiar with ACI method now. An
attempt to modify and adopt the Japanese in order to be easy and familiar is carried out in this study.
The concept is the same with the Japanese method but substituting the strength evaluation of thevertical members by ACI method and the ductility factor evaluation is followed by the first levelscreening of the Japanese method. The sample Lecturer House building from case study II was usedagain to evaluate with this modified method.
5. CASE STUDY OF THE JAPANESE AND MYANMAR BUILDINGS
5.1. Case Study of A Community Center Building in JapanThe seismic performance of a Community Center Building in Tsukuba City, Ibaraki Prefecture, Japan
which is a two-story reinforced concrete structure with concrete load bearing walls was evaluated as acase study in this paper. It was built in 1980 with old building codes before the revision inconsideration of ultimate capacity design. . The height of the story for the first floor is 3.5 m and thesecond floor is 6 m. The first floor has a floor area of 499.17 m2 and the second floor has 338.79 m2. It
has some minor damages by the 2011 Great East Japan Earthquake (Tohoku Earthquake). Thebuilding has some cracks on the interior and exterior reinforced concrete walls on both directions bythe Tohoku Earthquake. The cracks are visible and from 0.2mm to 0.45mm wide. They are the minor
damages and the damage levels of I and II. A cylinder test was conducted after being damaged by
the 2011 Tohoku Earthquake and the compressive strengths for the 1st floor are 40.1, 36.1, 34 N/mm2
and 2nd floor are 36, 29.1, 37.4 N/mm2 respectively. By using the standard deviation method, thecompressive strength ( Fc ) 25.4 N/mm2 is obtained and that value was used in this case study of theseismic evaluation.

Photo 1. The community center building

Figure 1. First floor plan of the communitycenter building
5.2. Case Study of a Lecturer House from Myanmar
The seismic evaluation was conducted for a lecturer’s house designed by our department using theJapanese Method to compare the results. This building was built in 2012. It was situated in theSagaing University Campus. It was a two-story RC building with brick infill wall. The brick infill
walls were designed as non-structural elements and their strengths were neglected in this evaluation.
Cube tests for compressive strength were carried out during under construction period and the meanvalue of these strengths, 17.24 newton per millimeter square was used in this evaluation. The yield4

strength of the steel reinforcement (deformed bar) used in this calculation was 275 newton per
millimeter square. This two-story RC building has a floor area of 108 square meters in the second
floor and 95 square meters in the first floor. The story height of the first floor is 3.05 meters (10 feet)and the second floor is 3.35 meters (11 feet).

Figure 3. Front elevation
Figure 2. First floor plan
5.3. Results of Seismic Evaluation for Japanese building and Myanmar building
The calculated results of the Community Center Building and Myanmar Lecturer House Building arecompared as shown in the table below.
Table 1 The result comparison of Japanese and Myanmar building
Evaluation
StoryMethod
2
1st level
1screening
212
2nd level
1screening
2
1Direction
XYX
Y

Case study I (Japanese Bld.)IsCTU SD
Evaluation
1.66
Safe
1.7
Safe
1.42
Safe
1.82
Safe
1.22
0.96
Safe
1.15
1.37
Safe
0.81
1.01
Safe
1.05
0.54
Safe

Case study II (Myanmar Bld)IsCTU SD
Evaluation
0.49
Not safe
0.37
Not safe0.49
Not safe
0.35
Not safe
0.83
0.32
Safe
1.16
0.27
Not safe
0.88
0.34
Safe
0.49
0.25
Not safe

According to the above results the community center building is safe. It is found to be agreeing withthe real practice because that building has only minor damages in the damage level of I and II
according to Japanese Guidelines by the Great East Japan Earthquake. But our Myanmar building isnot safe if it were judged by the Japanese demand index. There is a big difference between theseismicity of Myanmar and Japan. Therefore, setting up an appropriate demand index for a country is
an important issue in disaster mitigation and that is a key role factor to keep the alive its evaluation
method. By comparing the results of case study I and II, Myanmar buildings are significantly lower instrength but the ductility indices are apparently larger than the Japanese values.
The following table shows the comparison of the results of the modified adopted method andJapanese method.

5Is00.8

0.6

Table 2 Comparison of Is values(a) X-direction

Story21Modifiedmethod
0.37
0.35

1st levelscreening0.49
0.35(b) Y-direction
2nd level
screening
0.83
<0.3

Story

Modified
method

1st level
screening

2nd level
screening

21

0.37
0.32

0.49
0.37

0.88
<0.3

The seismic indices in the second level screening are higher because in the second level screening theductility dominant factor in all members are considered. The strengths evaluated by the ACI have alittle higher value so the seismic indices obtained by the interaction of these strength and ductility
index have a bit higher value. But all are in consistent behavior and likely to be in same results.
6. CONCLUSIONS
Results from case study I proved that the results from the Japanese Standard and Guidelines for
Seismic evaluation level I and II screening coincide with the situation of the building struck by the2011 Great East Japan earthquake. Therefore, these evaluation methods are good enough to beadopted for checking the seismic performance of existing and new RC low rise buildings in Myanmar
after making some modifications and simplifications. However, this modified evaluation method is a
first stepping stone to become a typical evaluation method for RC buildings in Myanmar.
The sustainable study and research works have to be carried out for better accuracy andprecision of this method. Research and survey works should be in sustainable action to set up a basic
seismic demand index for Myanmar.
7. RECOMMENDATION
It is recommended to evaluate the ductile RC structures with relatively weak beams by the third levelscreening method. A good result is desirable for a low rise RC structure up to six stories. Japaneseequations used in this evaluation method are the empirical formula which is based on experiments.
The vertical member size and reinforcements of Myanmar buildings are fairly smaller than theJapanese buildings and therefore there may have some errors. It is also recommended to develop
another modification to simplify the procedure that is most likely required to be able to get results in
rapid assessment to use the procedure on a daily basis, as the first level screening of the Japanesemethod. Another option is the automation with computer aided for the process interacting with thedominant ductility feature of each vertical member.
ACKNOWLEDGEMENTS
I would like to express my gratitude to my supervisor Dr. Seitaro TAJIRI, a senior researcher from theBuilding Research Institute for his insightful comments, suggestions and guidance. I would like tothank my advisor Mr. Mizuo INUKAI for giving me practical and useful advices. I also thank Dr.
Koichi MORITA, Dr. Toshihide KASHIMA, Dr. Masanori TANI and all of our professors from
BRI/IISEE, GRIPS, other institutions and universities for their sincere contribution with theirknowledge.
REFERENCES
Arthur H. Nilson, David Darwin, Charles W. Dolan, 2004, Design of Concrete Structures,
Kaminosono, T., 1992, International Symposium on Earthquake Disaster Prevention, Volume II, pp.
44-53.
The Japan Building Disaster Prevention Association (JBDPA) (1st English Version 2001).” JBDPA

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