Proceedings of the International Symposium on Engineering Lessons Learned fromthe 2011 Great East Japan Earthquake, March 1-4, 2012, Tokyo, Japan

CORRELATION ANALYSIS OF A
REINFORCED-CONCRETE BUILDING UNDERTSUNAMI LOADS AND EFFECT OF MASONRYINFILL WALLS IN TSUNAMI RESISTANCE
Anat Ruangrassamee1 and Piyawat Foytong2
1

Assistant Professor, Department of Civil Engineering, Chulalongkorn University,
Bangkok, Thailand, fcearr@eng.chula.ac.th2
Graduate Student, Department of Civil Engineering, Chulalongkorn University,
Bangkok, Thailand, piyawat_pwf@yahoo.com

ABSTRACT: The December 26th, 2004 Indian Ocean tsunami caused damage to manybuildings and killed many people in many Indian Ocean countries and the South ofThailand. Almost reinforced-concrete buildings in Thailand are the gravity load designed
buildings and damaged ranging from no damage to collapse from that event. To
understand behavior of a reinforced-concrete building, one-story building which is theformer office of Thai Meteorological Department located in Phang-Nga province wastested under tsunami load pattern. In this research, the reinforced-concrete building
model is constructed by using 3-dimensional non-linear static pushover analysis. In thebuilding model, masonry infill walls are considered and idealized as the diagonal stud by
using uniaxial non-linear springs. The results of the building model agree well with thetest results on the displacement of each frame and damage on the masonry infill walls.
The masonry infill wall in the middle frame can resist the lateral load of the top part load
about 60%. This building with masonry infill walls can resist the lateral load 3 times
higher than the resisting load of this building without masonry infill walls. To analyze theeffect of masonry infill wall of reinforced-concrete building, the patterns of the wall are
rearranged. The masonry infill walls with the appropriate arrangement can significantly
improve the load resisting capacity of the building.

Key Words: tsunami, tsunami load, reinforced concrete, building, nonlinear analysis

INTRODUCTION
The December 26th, 2004 Indian Ocean tsunami caused damage to several buildings in southern
provinces of Thailand. Reinforced-concrete buildings in the area are mainly designed for gravity loads.
One-story building which is the former office of Thai Meteorological Department located inPhang-Nga province was tested under tsunami load patterns. This research focuses on correlation
analysis that experimental results to evaluate forces distribution in each member, the lateral resistance528

force and the damage of building under tsunami loading. The building model is analyzed by using
non-linear static pushover analysis with TDAPIII program. A 3-dimensional fiber analytical model isused to analyze the building model. The masonry infill wall is considered and idealized as the diagonal
stud by using uniaxial non-linear springs. To analyze the, effect of masonry infill walls in a tsunami
load resisting capacity and to be the design guideline of reinforced-concrete buildings with masonry
infill wall, the patterns of the wall are rearranged.

DAMAGE OF BUILDING DUE TO 2004 INDIAN OCEAN TSUNAMI
The December 26th, 2004 Indian Ocean tsunami caused damage to buildings in Indian Ocean
countries. The damage of buildings were reported and analyzed by several researchers (Ruangrassmee
et al. 2006). Damage to reinforced-concrete buildings ranged from no damage to collapse. To
understand behavior of a reinforced-concrete building, the former office of Thai Meteorological
Department located in Phang-Nga province was tested by Lukkunaprasit et al. (2010). As shown in
Fig. 1, this building was exposed to the tsunami inundation height of 4.4 m and damaged in
non-structural members. In the test, the lateral pushover force was applied to represent thehydrodynamic force due to the tsunami. Fig. 2(a) depicts the pushover test setup and Fig. 2(b) shows
the relationship of lateral force and displacement of each frame.

Fig. 1 The former office of Thai Meteorological Department in Phang-Nga(Lukkunaprasit et al. 20010)
450
400

Load (kN)

350
300
250
200
150

Frame_A

100

Frame_B

50

Frame_C

0
0

2

4

6

8

10

12

14

16

Displacement (mm): Reference at base(a) Test setup(b) lateral force vs displacement relation

Fig. 2 Pushover test setup and results (Lukkunaprasit et al. 2010)

529

ANALYTICAL MODEL
In this study, the building model is analyzed by using non-linear static pushover analysis withTDAPIII program. A 3-dimensional fiber analytical model is used to predict the reinforced-concretebuilding under tsunami loading. The model is used to evaluate forces distribution in each member, thelateral resistance force and the damage of building under tsunami loading.
Reinforced-concrete frames
Analytical modelA 3-dimensional fiber model is used in the plastic region at the end of beams and columns to predict
the behavior of reinforced-concrete frames. The plastic lengths of beams and columns are evaluated byusing the equation proposed by Pauley and Priestley (1992). The fiber model consists of theunconfined concrete model, confined concrete model, longitudinal reinforcement model. The
stress-strain relationship of unconfined concrete is modeled using the equation proposed by Kent andPark (1971). The stress-strain relationship of confined concrete is modeled using the equation
proposed by Hoshikuma et al. (1997). The stress-strain relationship by Menegotto and Pinto (1973) isused for longitudinal reinforcement. The shear failure is considered using a non-linear spring as
proposed by Sezen and Mohele (2004).
Comparison with test results
To validate the structural model, the experimental results by Wehbe et al. (1999) and Anil and Altin(2007) are considered. From the study by Wehbe et al. (1999), the rectangular reinforced-concrete
column with 308 mm x 610 mm section was tested under cyclic loading and subjected to the axial
force of 615 kN. The column height was 2.050 m. The analytical column model consists of the zero
length shear spring, the fiber section element, and the elastic element. The calculated plastic length ofthe column is 0.352 m. The comparison between analytical result and experimental result of thiscolumn is shown in Fig. 3. The verification of analytical results is shown in Table 1. It is found that thereinforced concrete column model can capture the actual behaviors satisfactorily. For the initialstiffness, the analytical result is close to but slight higher than the experiment result. For shear strength
at first yield, analytical result agrees well with but slight less than the experiment result.

Lateral Load (kN)

500
300
100
-100
Analytical
Experimental

-300
-500
-200

-100
0
100
Lateral displacement (mm)200

Fig. 3 Comparison of experimental results by Wehbe et al. (1999) and analytical results
Table 1 Verification of analytical results with experimental results of Wehbe et al. (1999)

Experiment
Analysis
Ratio

Initial Stiffness (kN/m) Shear strength at yield (kN)21284.4
262.323379.2
255.2
1.10
0.97

530

Mode of Failure
FlexureFlexure-From the study by Anil and Altin (2007), the reinforced-concrete frame with the 100 mm x 150
mm column section and 150 mm x 300 mm beam section was tested under cyclic loading without
axial force. The frame had columns with a height of 750 mm and a 1,500 mm long beam. The
analytical model of the frame consists of the zero length shear springs at the end of columns, the fiber
section elements at the end of the columns and the beam, and elastic elements as shown in Fig. 4. The
plastic lengths are 0.174 m and 0.150 m for the columns and beam, respectively. The comparison
between analytical result and experimental result of this column are shown in Fig. 5. It is found thatthe reinforced concrete column model can capture the actual behaviors satisfactorily. The verificationof analytical results is shown in Table 2. For the initial stiffness and the shear strength, the analyticalresult is close to but slight less than the experiment result.

Fig. 4 Analytical model of bare frame
40

Shear Force (kN)

30
20
10
0

-10
-20
Analytical
Experimental

-30
-40
-60

-40

-20
0
20
40
Lateral displacement (mm)60

Fig. 5 Comparison of experimental results by Anil and Altin (2007) and analytical results
Table 2 Verification of analytical results with experimental results of Anil and Altin (2007)

Experiment
Analysis
Ratio

Initial Stiffness (kN/m) Shear strength at yield (kN)
4500.024.64422.8
23.2
0.98
0.94

Mode of Failure
Flexure in columns
Flexure in columns-

Masonry infill wall
Analytical model
There are several models to idealize masonry infill walls. The diagonal stud was used in this research.
For the lateral resisting force capacity of infill wall, the formulas proposed by FEMA 306 (1998) andMostafaei and Kabeyasawa (2004) are considered. The experimental results of Mehrabi et al. (1996)

531

are used to validate the masonry infill wall model. Four specimens were tested under monotonic
loadings with the same RC frames, but they were different in the masonry types and the distribution of
axial loads. The frame consisted of columns with a height of 1.537 m and a 2.312 m long beam.
Table 3 shows the comparison of the lateral resisting forces with calculated forces by equations by
FEMA 306 (1998) and Mostafaei and Kabeyasawa (2004). The resisting forces calculated fromequations by Mostafaei and Kabeyasawa (2004) agree well with the experimental results, thus theequation by Mostafaei and Kabeyasawa (2004) was used to calculate the wall resisting force.
Table 3 Comparison of lateral resisting forces
Specimen
No.
2
3
8
9

Experiment (1)14515.1
28304.5
19368.629846.7

Mostafaei andKabeyasawa (2)14215.1
23845.1
14975.921898.6

FEMA 306 (3)(2)/(1)(3)(1)

8884.414017.8
9178.313059.8

0.98
0.84
0.77
0.73

0.61
0.50
0.47
0.44

Comparison with test results
The masonry infill wall and frame was modeled as shown in Fig. 6. The masonry infill wall ismodeled as a diagonal stud. The fiber sections are used in the plastic region at the end of beams andcolumns. The plastic lengths are 0.174 m for columns and 0.237 m for a beam. Shear springs are used
to capture shear behaviors of columns and beam-column joints are assumed to be rigid. The
comparison of the lateral load and lateral displacement relationship between the experimental results
and analytical results for all four specimens are shown in Fig. 7. The verification of analytical results
is shown in Table 4. It is found that the model can capture the maximum load satisfactorily. The
stiffness of analytical results is the same trend as the stiffness of experiment. For the specimen No. 2,
the control of one of two actuators was lost, and then the data before cracking of the wall were notrecorded. Therefore, the actual lateral load may be higher than the presented result. The energy
dissipation of each specimen is computed for experiments and analysis with the same lateraldisplacement. The energy dissipation of the specimen No. 3 and No. 9 from the experiment is higher
than that from the analysis because the lateral loads of the analysis quickly dropped after the peak
point.

Fig. 6 The analytical model of bare frame with masonry infill wall model
Table 4 Verification of analytical results with experimental results of Mehrabi et al. (1996)
Specimen
No.2
No.3
No.8
No.9

Stiffness (kN/m)
Exp.
Ana.
Ratio
20158.1
32285.7
1.60129639.5 56372.4
0.43
57812.2
42201.2
0.73103361.2 57828.0
0.56Shear strength (kN)Exp. Ana. Ratio
142.4 207.3 1.46
277.7 290.1 1.04
190.0 211.9 1.12
292.8 270.3 0.92

532

Energy dissipation (kN-m)
Exp.
Ana.
Ratio
2.57
3.60
1.40
7.50
6.51
0.87
7.24
7.97
1.10
10.44
7.99
0.77

300

250

250

Lateral Load (kN)

Lateral Load (kN)

300

200
150
100
Analytical
Experimental

50

200
150
100
Analytical
Experimental

50
0

0
0

10

20
30
40
Lateral displacement (mm)

0

50

300

300

250

250

200
150
100
Analytical
Experimental

50

20
30
40
Lateral displacement (mm)50(b) Specimen No.3
Lateral Load (kN)

Lateral Load (kN)(a) Specimen No.2

10

200
150
100
Analytical
Experimental

50
0

0
0

10

20
30
40
Lateral displacement (mm)50(c) Specimen No.8

0

10

20
30
40
Lateral displacement (mm)50(d) Specimen No.9

Fig. 7 Comparison of experimental and analytical results

CORRELATION ANALYSIS OF RC BUILDING SUBJECTED TO TSUNAMI LOADSThe reinforced-concrete building which was the former office of Thai Meteorological Department inPhang-Nga Province was tested as mentioned in the previous section. The correlation analysis isconducted to understand the behavior of the building and investigate the effect of masonry infill wall.
This building is a one-story reinforced-concrete building. The building plan is illustrated in Fig. 8.
Fig. 9 shows the positions of the masonry infill walls. There is no masonry infill wall in the frame A.
For the frame B, there is the masonry in filled wall at the front span. For the frame C, there are walls
under window panels. The percentage of masonry infill walls is 21.8% in the plane parallel todirection of tsunami flows. The compressive strength of concrete obtained from in-situ coring was 12MPa, and the yield strength of reinforcement was 240 MPa. The span to depth ratio of the column is7.625. The axial load ratio is 0.128. The longitudinal reinforcement ratio and volumetric ratio oftransverse reinforcement are 0.0113 and 0.0038, respectively. Due to the large shear span ratio, thecolumn is governed by the flexural failure. The analytical models validated in the previous section areused in the correlation study. The building model is analyzed by using 3-dimensional non-linear
pushover analysis under force control as shown in Fig. 10. Six point loads consisting of three point
loads at the roof level and another three point load at the floor level are applied to the building at thesame locations as the field load test. These point loads represents hydrodynamic forces acting on
tributary areas. The fiber sections are used in the plastic region at the end of beams and columns. The
masonry wall is modeled as a diagonal springs. The ground and roof slabs are modeled as rigid
diaphragms.

533

(a) Ground plan(b) 1st and roof floor plan

Fig. 8 Plan of the former office of Thai Meteorological Department(a) Frame A(b) Frame B(c) Frame C
Fig. 9 The location of masonry infill wall of each frameFig. 10 3-dimensional model of the building

534

The comparison of lateral load and lateral displacement relationship between the experimental
results and analytical results of each frame are shown in Fig. 11. In analytical results, the load
resistance is 380.8 kN, and the load resistance at the roof level is 184.70 kN. The load resistance of theanalysis is slightly less than the load resistance of the experiment, 381.4 kN, because the load
resistance of the analysis that is limited by the lateral strength of the masonry infill wall in the frame B.
Considering the load resistance at the roof level, the load distributions of each frame are 21.23 kN,
136.69 kN and 26.77 kN for frame A, frame B and frame C, respectively. The masonry infill wall inframe B and frame C can resist the lateral load of the roof level about 63.1% and 24.6%, respectively.
It means that the lateral load distributes to the building frame only 12.3%. The ductility responses of
the column in frame A, B and C are about 1.3, 1.0 and 0.2, respectively. From Figure 19, it can be seenthat the analytical model can capture the initial stiffness well however the lateral displacement fromthe analysis is slightly larger. Fig. 12 shows the comparison of the torsion displacement at the roof
level. Fig. 13 shows the comparison of the lateral displacement for the ground level, the first floor
level and the roof level of each frame. From Fig. 12 and Fig. 13, the displacements of the analysis areagree well with the displacements of the experiment, but for the large lateral load, the displacements of
the analysis exceed the displacements of the experiment. Because, as discussing previously, themasonry infill wall in frame B is the primary member to resist the lateral load, then when the lateralload is larger, the wall in frame B resists the load exceeding the lateral yielding force of the wall;consequently, the building model is deformed so much. From the lateral resistance of the building
model limited by the strength of the wall in frame B, this result agreed well with the field load test thatcracks on the masonry infill wall in the frame B significantly widened at the maximum lateral load,
and there are new cracks occurred during the test as shown in Fig. 14, the crack width of the infill wallin frame B at initial state, maximum lateral load and unloading. The numbers in this figure are thewidth of the crack in mm unit.

Lateral resistance (kN)

500

400
300
200
Experiment

100

Analysis
0
0.000

400
300
200
100
0

0.005
0.010
0.015
Displacement (m)

0.020

0.000

(a) Frame A

0.005
0.010
Displacement (m)(b) Frame B

500
Lateral resistance (kN)

Lateral resistance (kN)

500

400
300
200
100
0
0.000

0.005
0.010
Displacement (m)0.015(C) Frame C
Fig. 11 The force and displacement relationship of building model

535

0.015

18
58.7 kN
Experiment165.1 kN
Experiment269.8 kN
Experiment381.4 kN
Experiment58.7 kN
Analysis165.1 kN
Analysis269.8 kN
Analysis380.8 kN
Analysis

16

Displacement (mm)

14
12
10
8
6
4
2
0
Frame A

Frame B

Frame C

Fig. 12 Comparison of the roof displacement of each frame
Roof

Roof

1st Floor

1st Floor

GroundGround

-5

0

5
10
15
Displacement (mm)

20

-5

0

5
10
15
Displacement (mm)(a) Frame A(b) Frame B
58.7 kN
Experiment165.1 kN
Experiment269.8 kN
Experiment381.4 kN
Experiment58.7 kN
Analysis165.1 kN
Analysis269.8 kN
Analysis380.8 kN
AnalysisRoof

1st Floor
Ground

-5

0

5
10
15
Displacement (mm)20(C) Frame C
Fig. 13 Comparison of the lateral displacement for each elevation of each frame

536

20

(a) Initial(b) Maximum load(c) Unloading
Fig. 14 Crack width of the masonry infill wall in frame B

EFFECT OF MASONRY INFILL WALL ON TSUNAMI RESISTING CAPACITY
The effect of masonry infill wall is investigated by arranging patterns of walls. The building modelis analyzed with the same load pattern as the field load test. The names of each masonry infill wall aredenoted as in Fig. 15. A, B, and C denotes the infill wall in both front and back spans in the frames A,
B, and C, respectively.

Fig. 15 Definition of masonry infill walls
Table 5 Results of rearranged masonry infill wallNo

Description

1
2
3
4
5
6

Without wall
A
B
A-C
A-B-C
A1-B1-C1

Percentage of
Max Load (kN)
FailureInfill Wall
0.0
138.8
All Columns
33.3
162.1
Columns in Frame C
33.3
694.1
Shear in Short Columns
66.7
704.6
Shear in Short Columns
100.0
706.2
Shear in Short Columns
50.0
685.4
Shear in Short Columns

537

Latteral Resisting Force (kN)

800
700
600
500
400

Eccentric w/o frame B wall
Eccentric w/ frame B wall
Concentric
Existing building

300
200
100
0
0

20

40
60
80
Percentage of Masonry Infilled Wall

100

Fig. 16 Relationship of lateral resisting force and percentage of infill wall
Table 5 summarizes the cases and results from the analysis. Several arrangement patterns of walls
are considered and it is found that if there is no wall in the building the load resistance of the building
is limited to only 138 kN which is governed by flexural failure of columns. If walls are provided in theframe A, torsional effect will result in the flexural failure of columns in the frame C. The wall in theframe B will significantly increase the lateral load capacity of the building to about 700 kN. If walls
are provided in all frames, the load resistance is about 700 kN which is limited by shear failure ofshort columns. Fig. 16 illustrates the relation of lateral load resisting capacity vs percentage of walls. It
is obvious that providing the wall in the frame B (33% of walls) is the most effective pattern to get alarge tsunami resisting capacity. The building is subjected to shear failure of short columns under thefloor slab.

CONCLUSIONSThis research studies on the correlation analysis of the reinforced-concrete building with masonry
infill walls under tsunami loading and the effect of masonry infill walls in a tsunami load resisting
capacity. The former office of Thai Meteorological Department located in Phang-Nga province is thedefault building of this study. Findings can be summarized as follows:
1) The former office of Thai Meteorological Department located in Phang-Nga province is used
for the 3-dimensional nonlinear pushover analysis. Material models are selected and compared withtest results before applying to the building. Then the 3-dimensional models are developed andsubjected to the load pattern similar to the field test assumed as the uniform pressure due to thetsunami hydrodynamic force by using force controlled method. The good agreement is obtained
between the test and analysis.
2) It is found that masonry infill walls play a major role in the tsunami load resisting capacity ofthe building. Hence the effect of infill walls is investigated by varying the arrangement pattern to findthe effective pattern of walls. If there is no wall in the building the load resistance of the building islimited to only 138 kN which is governed by flexural failure of columns. The wall in the middle frame
significantly increases the lateral load capacity of the building to about 700 kN. If walls are provided
in all frames, the load resistance is about 700 kN which is limited by shear failure of short columns. It
is obvious that providing the wall in the middle frame is the most effective pattern to get a large lateralload resisting capacity. However, the building is subjected to shear failure of short columns under thefloor slab. Enhancement of the shear capacity of the short columns will improve the performance of
this building.

538

ACKNOWLEDGMENTS
Office of the Higher Education Commission, Ministry of Education, Thailand is gratefully
acknowledged. The assistance of Dr. Nuttawut Thanasisathit is also acknowledged.

REFERENCES
Anil, O. and Altin, S. (2007). “An experimental study on reinforced concrete partially infilled frames.”
Engineering Structures, Vol. 29, 449-460.
FEMA 306. (1998). “Evaluation of earthquake damaged concrete and masonry wall buildings - Basic
procedures manual.” Federal Emergency Management Agency, Washington, DC.
Hoshikuma, J., Kawashima, K., Nagaya, K. and Taylor, A. W. (1997). “Stress-strain model for
confined reinforced concrete in bridge piers”. Journal of the Structural Engineering, ASCE, Vol.
123, No. 5, 624-633.
Kent, D. C. and Park, R. (1971). “Flexural members with confined concrete.” Journal of StructuralEngineering, ASCE, Vol. 97, No. 7, 1969-1990.
Lukkunaprasit, P., Ruanrassamee, A., Stitmannaithum, B., Chintanapakdee, C. and Thanasisathit, N.
(2010). “Calibration of tsunami loading on a damaged building.” Journal of Earthquake andTsunami, Vol. 4, No. 2, 105-114.
Mehrabi, A. B., Shing, P. B., Schuller, M. P. and Noland, J.L. (1996). “Experimental evaluation ofmasonry-infilled RC frames.” Journal of Structural Engineering, Vol. 122, 228-237.
Menegotto, M. and Pinto, P. (1973). “Method of analysis for cyclically loaded RC plane frames
including changes in geometry and non-elastic behavior of elements under combined normal force
and bending.” Symp. Resistance and ultimate deformability of structures acted on by well defined
repeated loads, IABSE Reports, Vol. 13, Lisbon, Portugal.
Mostafaei, H. and Kabeyasawa, T. (2004). “Effect of infill masonry walls on the seismic response ofreinforced concrete buildings subjected to the 2003 Bam Earthquake strong motion: A case study of
Bam telephone center.” Bulletin Earthquake Research Institute Univ. Tokyo, Vol. 79, 133-156.
Paulay, T. and Priestley, M. J. N. (1992). “Seismic design of reinforced concrete and masonry
structures.” John Wiley and Sons, Inc., New York, USA.
Ruangrassamee, A., Yanagisawa, H., Foytong, P., Lukkunaprasit, P., Koshimura, S. and Imamura, F.
(2006). “Investigation of tsunami-induced damage and fragility of buildings in Thailand after the
December 2004 Indian Ocean tsunami.” Earthquake Spectra, Vol. 22, S377–S401.
Sezen, H. and Moehle, J. P. (2004). “Shear strength model for lightly reinforced concrete columns.”
Journal of Structural Engineering, ASCE, Vol. 130, 1692-1703.
Wehbe, N. I., Saiidi, M. S. and Sanders, D. H. (1999). “Seismic performance of rectangular bridge
columns with moderate confinement.” ACI Structural Journal, Vol. 96, No. S27, 248-259.

539