WCCE – ECCE – TCCE Joint Conference: EARTHQUAKE & TSUNAMI
SHEAR BEHAVIOR OF HOLLOW BRICK INFILL WALL PANELS STRENGTHENED BY PRECAST
REINFORCED CONCRETE PANELS AND STEEL FIBER REINFORCED PLASTER
A Preliminary Study for RC Frame Strengthening
D. Okuyucu1, T. Sevil2, E. Canbay3
ABSTRACT
More than 90% of the land area of Anatolian Peninsula is located over one of the most active
seismic zones in the world. Hazardous earthquakes frequently occur and cause heavy damage to
the economy of the country as well as human lives due to the destructions of non-engineered
structures. This reality created a need of developing practical and reliable strengthening methods for
existing vulnerable building stock in Turkey. In the last decade, a number of strengthening methods
for reinforced concrete framed structures were evaluated experimentally in METU Structural
Mechanics Laboratory in order to develop practical and efficient strengthening techniques as an
alternative to cast-in-place RC infill application which requires evacuation of the inhabitants.
Attachment of high strength precast concrete panels to the existing infill brick walls by epoxy mortar
and introducing steel fiber reinforced plaster onto the existing infill brick wall were evaluated on
scaled frame tests experimentally. As the preliminary stage of the study, shear behavior of
strengthened hollow brick infill wall panels were investigated experimentally. Total of 46 infill panels
were subjected to diagonal compression. This preliminary study showed that, both proposed
techniques increase the shear capacity of individual hollow brick infill walls. Details of this study and
results of the infill wall panel tests are presented in this manuscript.
Keywords: Hollow Brick Infill, Steel Fiber, Precast Concrete Panel, Wall Strength, Shear Behavior,
Experimental.
1. INTRODUCTION
A great percentage of population in Turkey is located on highly active seismic zones and a great percentage
of occupants reside in vulnerable RC framed structures which are under high damage/collapse risks even for
a moderate seismic excitation. New, safe structures have been constructed by incorporating recent advances
in architecture and structural engineering. Existing vulnerable buildings, however, will be under service during
a major earthquake in the near future. Rehabilitation of such structures is required as urgent measures so that
they could remain operational after an earthquake. Therefore, their seismic resistance must be insured.
Non-Structural infill walls of RC buildings are constructed by hollow brick masonry. Studies have shown that,
infilled walls which are generally considered as non-structural elements, affect the lateral strength and
stiffness characteristics of the framed buildings under lateral seismic excitation [1, 2, 3, 4]. It is also
experimentally proved that, the replacement of existing infill walls by cast-in-place reinforced concrete infills
considerably improves seismic behavior of the structural system. Reinforced concrete infills decrease the load
effects on deficient frame members by carrying considerable amount of seismic forces and improve seismic
behavior of the structure by increasing lateral strength and stiffness of the system [5, 6, 7, 8, 9]. Therefore,
infill walls are a meaningful starting point to improve structural behavior under the lateral dynamic loads.
Cast-in-place RC infill application, as the most common strengthening technique in Turkey, is a time
consuming procedure and requires evacuation of inhabitants during the application. A number of alternative
techniques for strengthening RC framed structures which do not necessitate evacuation were experimentally
investigated in METU Structural Mechanics Laboratory in the last decade [10, 11, 12, 13, 14]. The main
objective of the research was to provide new, practical, efficient and occupant friendly strengthening
techniques for existing vulnerable RC building stock in seismic regions of Turkey. The basic idea is that if the
existing non-structural infill walls can be converted into load bearing structural members like RC
infills by practical methods, then the similar/same seismic behavior improvement can be obtained.
Introducing high strength precast concrete panels on the existing brick infill wall surface by a thin layer of
epoxy mortar and application of steel fiber reinforced plaster onto the existing infill plaster as second layer
are the two of the proposed strengthening techniques. In both methods, the infill is not replaced by any
material; it is only strengthened by new layers and a number of anchorage dowels are provided in between
1
PhD Candidate, METU & Res. Asst., Atatürk University, Erzurum, Turkey
PhD Student, Middle East Technical University, Ankara, Turkey
3
Associate Professor, Middle East Technical University, Ankara, Turkey
2
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WCCE – ECCE – TCCE Joint Conference: EARTHQUAKE & TSUNAMI
existing frame members and new layers for a monolithic structural nature in that particular frame part. As the
preliminary stage of the research, shear behavior and strength of the individual hollow brick infill wall panels
strengthened by means of the proposed techniques were experimentally investigated, prior to RC frame tests.
RC infill panels and brick infill wall panels were also tested to constitute maximum and minimum references.
[15, 16, 17, 18].
Tests were performed on 1:3 scale prototype walls. Total of 6 RC infill wall panels and 40 hollow brick infill
wall panels strengthened by proposed techniques with various properties were prepared in 1:3 scale and
tested under diagonal compression. All infills were square in shape, 700×700mm, and had varying
thicknesses according to the specimen properties. The tests were performed in 3 groups. 1st and 2nd groups
consist of the infill panels strengthened by steel fiber reinforced plaster application. 3rd group covers RC infills
as well as infill wall panels strengthened by high strength precast concrete panels. Non-plastered and
plastered hollow brick infill wall panels were also tested as reference specimens.
2. SPECIMEN DEFINITIONS
Infill wall panels were tested in three groups. First and second series cover the panels strengthened by steel
fiber reinforced plaster, and third group includes pure RC infills (representing cast-in-place RC infill
application) and hollow brick wall panels strengthened by precast concrete panels. Schematic views of test
specimens are given in Figure 1, Figure 2 and Figure 3. All panels were square in shape having dimensions of
700×700 mm. The dimensions and thickness may slightly vary remaining in acceptable engineering limits
because of workmanship. The specimen properties are given in Table 1. It should be noted that, at least 3
specimens were prepared for each specimen group. However, due to some technical problems of data
recording or damages in panel during the positioning of the specimen into the test setup, some of the tests
could not be taken into consideration and only 46 test results are presented.
Figure 1. Schematic Sectional Views of First Series Specimens and 1SNPP Specimen
Figure 2. Schematic Sectional Views of Second Series Specimens and 2SSF1P Specimen
Figure 3. Schematic Sectional Views of Third Series Specimens and 3SSPP Specimen
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Table 1. Summary Description of Test Specimens
Decription
Specimen
Hollow brick wall panel without plaster
1SNPP
Hollow brick wall panel with normal plaster on both sides
1SPP
Hollow brick plastered wall panel strengthened with
1SSF1P
10 mm thick steel fiber reinforced plaster on one side
Hollow brick plastered wall panel strengthened with
1SSF2P
20 mm thick steel fiber reinforced plaster on one side
nd
2 Group** Hollow brick wall panel without plaster
2SNPP
Hollow brick wall panel with normal plaster on both sides
2SPP
Hollow brick plastered wall panel strengthened with
2SSF1P
10 mm thick steel fiber reinforced plaster on one side
Hollow brick plastered wall panel strengthened with
2SSF2P
20 mm thick steel fiber reinforced plaster on one side
Hollow brick plastered wall panel strengthened with
2SSF1PD
10 mm thick steel fiber reinforced plaster on both side
Hollow brick plastered wall panel strengthened with
2SSF2PD
20 mm thick steel fiber reinforced plaster on both side
3rd Group*
Hollow brick wall panel with plaster on both sides
3SPP
Hollow brick plastered wall panel strengthened with
3SRPP
20 mm thick rectangular panels on one side
Hollow brick plastered wall panel strengthened with
3SSPP
20 mm thick strip panels on one side
Reinforced Concrete Infill Panel
3SRCP
* : Hollow brick wall panels have 10 mm thick mortar and 10 mm thick standard plaster.
** : Hollow brick wall panels have 6 mm thick mortar and 10 mm thick standard plaster.
Group
1st Group*
# 2 specimens
# 3 specimens
# 3 specimens
# 3 specimens
# 5 specimens
# 3 specimens
# 3 specimens
# 2 specimens
# 3 specimens
# 3 specimens
# 3 specimens
# 4 specimens
# 3 specimens
# 6 specimens
3. MATERIALS
Hollow brick infill wall is a non-homogenous, composite body, the mechanical properties of which depend on
individual characteristics of its constituents such as brick, mortar and plaster. Also, the interface properties of
the hollow brick and mortar/plaster and workmanship quality are of great importance. In this part, the
materials which were utilized in this experimental study and their mechanical properties will be presented.
The hollow bricks used in this research were a special production in 1:3 scale. The scaled bricks were
produced from the same material mix which is used to produce standard sized hollow bricks and cured under
the same conditions. The dimensions of 1:3 scaled hollow brick are given in Figure 4. In order to define
compressive strength of hollow brick; a number of randomly selected samples were subjected to uniaxial
compression test. The average compressive strengths of the hollow bricks with respect to the net and gross
sectional area were experimentally determined to be 27.3 MPa and 13.1 MPa, respectively with cov. = 0.10.
Figure 4. Hollow Brick Dimensions
The mortar and plaster were made with the same mix proportion for each group. Portland cement, lime,
fine aggregate and water were used in the mix. Besides, two different grades of concrete were used for
production of RC infills and high strength precast concrete panels. The maximum aggregate size was 3 mm
for mortar/plaster and 7 mm for concrete mixes. The cylinder samples of all mixes were kept under the same
conditions with infill panels and were subjected to the uniaxial compression tests at corresponding panel test
day. Although all mortar batches were prepared by using the same material and mix proportions, the
compressive strength differed considerably, as a preliminary indicator of variability in in-plane shear behavior
of non-homogenous infill wall panels. The compressive strength test results of all mortar and concrete mixes
are given in Table 2.
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1st Group
2nd Group
3rd Group
Table 2. Compressive Strength of Mortar and Concrete Samples
Mortar and
Steel Fiber Reinforced
Precast Panel
RC Infill Concrete
Plaster (MPa)
Plaster (MPa)
Concrete (MPa)
(MPa)
3.5
21.2
10.0
29.2
5.3
50.0
18.0
Specimens, except the reference ones (non-plastered and plastered panels), of 1st and 2nd group were
strengthened by steel fiber reinforced plaster. Several material tests were performed in order to obtain the
most appropriate steel fiber reinforced plaster mix. Different fiber ratios by volume of plaster and steel fiber
types were evaluated in the laboratory. The most important parameter was the workability of the steel fiber
reinforced plaster. Higher amounts of steel fiber and higher fiber aspect ratios resulted in difficulties in
workability of plaster together with a decrease in bond quality in between the existing plaster surface and new
reinforced plaster layer. Finally, 30 mm long steel fiber which has hooks at the ends was found to be
appropriate to be used as reinforcement of plaster by 2% percentage of plaster volume. The properties of
steel fiber are presented in Table 3.
Table 3. Properties of Steel Fiber
Length
Diameter
Min.Tensile Strength
Aspect Ratio
(mm)
(mm)
(MPa)
Steel Fiber*
30
0,55
54,5
1100
* : Steel fiber corresponds the requirements of ASTM A 820 and TS 10513.
Numerical Density
(# number / kg)
16750
1:3 scale, high strength reinforced precast concrete panels were prepared as the second strengthening
technique for the 3rd specimen group. 20 mm thick strip (700×120 mm) and rectangular (233×235 mm)
shape, high strength reinforced precast concrete panels were prepared in the laboratory. Panel types are
shown in Figure 5.
Figure 5. Reinforcement and Molding of Rectangular and Strip Panels
Both rectangular and strip panels were made of the same concrete mix. High strength precast concrete panels
were reinforced by one layer of welded wire steel mesh (Ø3/30mm). 60 mm thick RC wall panels were
reinforced by two layers of steel mesh (Ø6/150mm), which was made of plain bars and prepared in
laboratory without any welding representing the common application. The geometric and mechanical
properties of steel meshes are summarized in Table 4.
RC Panel
Precast Panel
Table 4. Properties of Steel Mesh Reinforcement
Mesh Spacing
Yield Strength
Diameter (mm)
(mm)
(MPa)
6
150
340
3
30
-
Ultimate Strength
(MPa)
460
680
The bonding agent used for attaching the high strength precast concrete panels to each other and infill wall
surface was SikaDur-31 epoxy mortar. This mortar is a two component adhesive with a tensile strength much
higher than that of concrete. The properties of SikaDur-31 epoxy mortar are given in Table 5, as stated in the
product catalog.
Table 5. Mechanical Properties of SikaDur – 31 Epoxy Mortar
Compressive
Tensile Strength
Adhesion (steel)
Strength (MPa)
(MPa)
(MPa)
SikaDur-31 Epoxy Mortar
65
20
20
4
Adhesion (concrete)
(MPa)
3.5
WCCE – ECCE – TCCE Joint Conference: EARTHQUAKE & TSUNAMI
4. TEST SET-UP AND PROCEDURE
All of the 46 specimens were tested under diagonal compression simulating the in-plane shear loading,
Figure 6. Due to laboratory intense schedule, two test setups were constructed in order to make tests
simultaneously. The first set-up was constructed on horizontal direction. 1st and 2nd group of test specimens
were tested in the first setup. This setup is supported by two stiff concrete blocks which are fixed on the strong
floor of the laboratory.
Figure 6. Views of Horizontal and Vertical Test Setups
The second setup for 3rd group specimens was constructed in a vertical load bearing stiff steel frame. Identical
hydraulic jacks, load cells, and measurement were used in both setups. Dial gages were used for
displacement measurements in two diagonal and two parallel to face directions.
Steel caps were placed to the specimen corners to prevent local crushing and to uniformly distribute the
applied load. Steel caps were fixed by means of gypsum mortar. All specimens except NPP were white washed
to observe crack patterns better. All specimens were tested under load control. Specimens were loaded
monotonically up to failure. An electronic Data-Acquisition system recorded the applied load and
deformations continuously.
5. TEST RESULTS
In this study, total of 1:3 scale, 46 infill panels with varying properties were tested under diagonal
compression. Due to non-homogenous structure of the panel body, it is very difficult to obtain any reliable
modulus of elasticity and Poisson ratio using the test data for any specimen. Even though the maximum load
capacities are closed to each other for each specimen group, these quantities (E, υ) varied a lot (cov.>>0.10)
Therefore, as a more reliable representation force–compression diagonal strain graphs are presented for
each group. Beyond the maximum load, the data was considered until the load decreases down to 80% of
Pmax to unify the representation of test data. Average maximum forces of each group were calculated and
these results will be presented for each group separately.
5.1. Test Results of the 1st Group Specimens
In the 1st group, total of 11 wall panels were tested under diagonal compression. The mortar thickness was 10
mm in all specimens. In Table 6, numerical results and comparisons are presented for this group.
Specimen
1SNPP
1SPP
1SSF1P
1SSF2P
Table 6. Summary of Test Results for First Group
At Max. Load Level
Maximum Load Capacity Comparison Compared to
Load (kN)
that of NPP
that of PP
10,4
~1,0 times
~0,3 times
31,9
~3,1 times
~1,0 times
68,8
~6,6 times
~2,2 times
103,4
~9,9 times
~3,2 times
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WCCE – ECCE – TCCE Joint Conference: EARTHQUAKE & TSUNAMI
1SNPP specimens failed in a very brittle manner. The failure was due to mortar between the hollow bricks and
the path was consequently stepwise diagonally between the loading corners. 1SPP specimens represent the
current infill walls in most RC framed structures in Turkey, and therefore, it is the main reference specimens of
the research. The test data shows that plaster existence on infill surface increases the ultimate load capacity
considerably (~3.1 times of 1SNPP). Tensile stresses perpendicular to the diagonal crack caused the failure of
1SPP specimens. 1SSF1P specimens were tested as the first strengthened wall panels by steel fiber reinforced
plaster and reached ~2.2 times ultimate load capacity of the reference 1SPP. 1SSF2P specimens were tested
as the last sub-group, resulting in ~3.2 times ultimate load capacity of the reference. In Figure 7, one test
data from each sub-group is presented.
200
1SNPP
1SPP
1SSF1P
1SSF2P
180
160
Load (kN)
140
120
100
80
60
40
20
0
0
1000
2000
Strain (microstrain)
3000
Figure 7. Load – Strain of Compression Diagonal Graphs for 1st Group Specimens
5.2. Test Results of the 2nd Group Specimens
Total of 19 wall panels were tested in 2nd group. The mortar thickness was 6 mm in all panels. The
mortar/plaster strength, however, was 10.0 MPa, while it was 3.5 MPa in 1st group specimens. In Table 7,
numerical results and comparisons for ultimate load capacities are presented for this group.
Specimen
2SNPP
2SPP
2SSF1P
2SSF2P
2SSF1PD
2SSF2PD
Table 7. Summary of Test Results for Second Group
At Max. Load Level
Maximum Load Capacity Comparison Compared to
Load (kN)
that of NPP
that of PP
44,1
~1,0 times
~0,8 times
57,6
~1,3 times
~1,0 times
83,9
~1,9 times
~1,5 times
119,7
~2,7 times
~2,1 times
138,0
~3,1 times
~2,4 times
148,2
~3,4 times
~2,6 times
In this series, total of 5 2SNPP specimens were tested. In the 1st group tests due to high slender nature of the
panel body, difficulty of placing non-plastered wall panels into the setup was experienced. In order to get
reliable number of test data, 5 specimens were prepared and all of them were successfully tested. The
average maximum load was reached to be 44.1 kN with a stepwise failure mode, while it was 10.4 kN in
1SNPP specimens. Approximately ~3 times increase in mortar strength results in ~4 times increase in
diagonal shear capacity, although the mortar thickness decreased from 10 mm to in 6 mm. 2SPP specimens
failed at an average maximum load of 57.6 kN due to increasing number of tensile cracks along the loaded
diagonal. The maximum average diagonal compressive force of 2SSF1P specimens was measured to be 89.9
kN resulting in an improvement of ~1.5 times of that of the reference specimen. However, it should be noted
that these panels behaved very stiff, when compared to 1SSF1P specimens. This can be attributed to higher
mortar and plaster strengths. 2SSF2P specimens reached an average ultimate diagonal compressive force of
119.7 kN. One test data from each sub-group is presented in Figure 8.
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Load (kN)
WCCE – ECCE – TCCE Joint Conference: EARTHQUAKE & TSUNAMI
200
180
160
140
120
100
80
60
40
20
0
2SNPP
2SPP
2SSF1P
2SSF2P
2SSF1PD
2SSF2PD
0
1000
2000
Strain (microstrain)
3000
Figure 8. Load – Strain of Compression Diagonal Graphs for 2nd Group Specimens
2SSF1PD specimens were the first panels which were strengthened by steel fiber reinforced plaster application
on both sides. These panels behaved very stiff up to ultimate load of 138.0 kN in average. The average
diagonal compressive force capacity of 2SSF2PD specimens can be stated as 148.2 kN. Besides, it should be
noted that capacities of 2SSF1PD and 2SSF2PD specimens varied a lot in each sub-group. Application of
reinforced plaster on both sides of the panel results in a considerable amount of increase in ultimate diagonal
compression capacity with respect to the one side application; but provided very stiff behavior as well as high
variation in ultimate strength.
5.3. Test Results of the 3rd Group Specimens
The last group specimens were tested in vertical loading setup. Total of 17 wall panels were successfully
tested. In all hallow brick wall panels the mortar and plaster are made of the same mix and thickness of 10
mm. Mortar/plaster compressive strength was 5.3 MPa. Numerical results of this series are presented in Table
8. One test data from each sub-group is presented in Figure 9.
Specimen
3SPP
3SRPP
3SSPP
3SRCP
Table 8. Summary of Test Results for Third Group
At Max. Load Level
Maximum Load Capacity Comparison compared to
Load (kN)
that of REF
64,7
~1,0 times
137,0
~2,1 times
176,0
~2,7 times
185,1
~2,9 times
Load (kN)
3SPP specimens reached the average ultimate diagonal compressive force of 64.7 kN and all specimens were
failed due to principal tensile stresses perpendicular to the diagonal crack in the loaded direction. 3SRPP
specimens were tested as the first strengthened infill wall panels. The average of ultimate diagonal force was
measured to be 137.0 kN, being ~2.1 times of that of reference specimens. During loading process, panel
concrete crushing occurred initially at the loading corner on the stiff side of the panel and then tension cracks
occurred on loaded diagonal (on the other side of the panel) prior to failure. On the free edges, separation
between brick and concrete panel layer was also observed.
200
180
160
140
120
100
80
60
40
20
0
3SPP
3SRCP
3SRPP
3SSPP
0
1000
2000
Strain (microstrain)
3000
Figure 9. Load – Strain of Compression Diagonal Graphs for 2nd Group Specimens
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WCCE – ECCE – TCCE Joint Conference: EARTHQUAKE & TSUNAMI
The average maximum diagonal compressive force of 3SSPP specimens was measured to be 176.0 kN;
approximately ~2.7 times of that of reference specimens. In these specimens, concrete crushing around
loading corner occurred on stiff side and diagonal tension cracks observed at other side together with corner
crushing prior to failure. 3SRCP specimens were tested as the upper bound reference of the 3rd group
specimens. First concrete crack occurred at different load levels in all 3SRCP panels. The average maximum
diagonal shear force was measured to be 185.1 kN; being very close to that of 3SSPP. In RC infills, tension
cracks occurred on the loading diagonal with increasing compressive force. Cracks widened together with
corner crushing prior to failure of panel.
6. CONCLUSIONS
The contribution of two different strengthening techniques on shear behavior of individual hollow brick infill
wall panels was experimentally investigated in this research. Average maximum loads of all specimen groups
are presented as bar charts in Figure 10. Some conclusions from the limited test results can be stated as
below.
Applying steel fiber reinforced plaster onto the existing plaster layer increases the diagonal compressive
capacity of hollow brick infill panels when compared to that of reference specimens. Some variables such as
one or two sided plaster application in either 10 mm or 20 mm thickness were evaluated. Double sided
strengthened specimens behaved very stiff up to the ultimate stage. It can be concluded that, one sided – 20
mm thick steel fiber reinforced plaster application has given the optimum results by means of maximum
diagonal compressive force and behavior.
Mortar/plaster strengths were different in both 1st and 2nd group specimens. The effect of mortar/plaster
strength on infill panel behavior is obvious for non-plastered infill panels in Table 9. Approximately 3 times
increase in mortar strength results in approximately 4 times increase in diagonal compressive capacity. Not
only for strengthening purposes but also for new constructions, it is suggested to give special attention for
mortar/plaster quality as well as workmanship of infill panels for better seismic performance of the structure.
Table 9. Effect of Mortar Strength
At Max. Load Level
Maximum Load Capacity Comparison Compared to
that of REF
10,4
44,1
~1,0 times
~4,2 times
RCP
SPP
RPP
SF2PD
3rd Group
SF1PD
2nd Group
SF2P
PP
1st Group
NPP
200
180
160
140
120
100
80
60
40
20
0
Load (kN)
SF1P
Mortar
Strength (Mpa)
1SNPP*
3,5
2SNPP**
10,0
* : Mortar thickness is 10 mm
** : Mortar thickness is 6 mm
Average Maximum Load (kN)
Specimen
Figure 10. Summary of Average Maximum Load Values
In 3rd group, application of both rectangular and strip shaped high strength precast concrete panels results in
~2.5 times increase in diagonal shear capacity in average when compared to that of plastered hollow brick
walls. The improvement is also very closer to the upper bound RC infill references.
This preliminary study showed that, both proposed techniques increase the shear capacity of individual hollow
brick infill walls. Attachment of anchorage dowels in between frame and new strengthening layers provides a
monolithic structure, which is similar to cast-in-place RC infill replacement. As a further information, in the
second step of the main research, both techniques were applied to deficient RC infilled frames considering a
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WCCE – ECCE – TCCE Joint Conference: EARTHQUAKE & TSUNAMI
number of parameters such as; aspect ratio, precast concrete panel type, steel fiber reinforced plaster
thickness, etc. and several frames were tested under reversed cyclic loading. The average seismic
performance improvement levels of frames by means of lateral load capacities are very similar to that of
individual wall panels.
Acknowledgements
This research was carried out in Middle East Technical University Department of Civil Engineering Structural
Mechanics Laboratory. The assistances of Mr. Osman KESKİN, Mr. Murat DEMİREL, Mr. Hasan METİN and
other laboratory staff is gratefully acknowledged. Part of the work was financed by The Scientific and
Technological Research Council of Turkey (TUBİTAK – Project Number 104M566).
References
[1] Benjamin, J. R., and Williams, H.A., “The Behavior of One Storey Brick Shear Walls”, Proceedings of
ASCE, v. 84, ST4., pp. 1723-1-1723-30, July, 1958.
[2] Smith, S., B., “Lateral Stiffness of Infilled Frames”, Journal of the Structural Division, Proceedings of ASCE,
88, No. ST 6., pp. 182-197, December, 1962.
[3] Bertero, V., and Brokken, S., “Infills in Seismic Resistant Building”, Journal of Structural Engineering, Vol.
109, No. 6, June, 1983.
[4] Govindam, P., Lakshmipathy. M., and Santhakumar, A., R., “Ductility of Infilled Frames”, ACI Structural
Journal, Technical Paper, Title No. 83-50, May-June, 1987.
[5] Klingner, R. E., and Bertero, V. V., “Earthquake Resistance of Infilled Frames”, Journal of structural
Division, Proceedings of the American Society of Civil Engineers, Vol. 104, No. ST6., June, 1978.
[6] Kahn, L.F., and Hanson, R.D. “Infilled Walls for Earthquake Strengthening”, Journal of the Structural
Division, Proceedings of the American Society of Civil Engineering, Vol. 105, No. ST2., February, 1979.
[7] Altin, S., Ersoy, U, and Tankut, T., “Hysteretic Response of Reinforced Concrete Infilled Frames”, Journal
of Structural Engineering, Vol. 118, No 8, August, 1992.
[8] Canbay, E., “Contribution of Reinforced Concrete Infills to the Seismic Behavior of Structural Systems”, A
Doctor of Philosophy Thesis in Civil Engineering, Middle East Technical University, Ankara, 2001.
[9] Sonuvar, M., O., Ozcebe, G., Ersoy, U., “Rehabilitation of Reinforced Concrete Frames with Reinforced
Concrete Infills”, ACI Structural Journal, V. 101, No. 4, July-August 2004.
[10] Duvarci, M. “Seismic Strengthening of Reinforced Concrete Frames with Precast Concrete Panels”, A
Master of Science Thesis in Civil Engineering, Middle East Technical University, Ankara, 2003.
[11] Süsoy, M., “Seismic Strengthening of Masonry Infilled Reinforced Concrete Frames with Precast Concrete
Panels”, A Master of Science Thesis in Civil Engineering, Middle East Technical University, Ankara, 2004.
[12] Baran, M., “Precast Concrete Panel Reinforced Infill Walls for Seismic Strengthening of Reinforced
Concrete Framed Structures”, A Doctor of Philosophy Thesis in Civil Engineering, Middle East Technical
University, Ankara, 2005.
[13] Erdem, I., “Strengthening of Existing Reinforced Concrete Frames”, A Master of Science Thesis in Civil
Engineering, Middle East Technical University, Ankara, 2003.
[14] Ozcebe, G. et. al., “Seismic Assessment and Rehabilitation of Existing Buildings, NATO SfP 977231,
2000.
[15] Holmes, M., Steel Frames with Brickwork and Concrete Infillings. Proceedings of the Intuition of Civil
Engineering, 19:473-478, 1961.
[16] Smith, S., B., “Methods for Predicting the Lateral Stiffness and Strength of Multi-Storey Infilled Frames”,
Building Science, Vol. 2, pp. 247-257, Pergamon Pres, Great Britain, 1967.
[17] Valuzzi, M., R., Tinazzi, D., and Modena, C., “Shear behavior of masonry panels strengthened by FRP
laminates”, Construction and Building Materials, Vol. 16, pp. 409–416, 2002.
[18] Gabor, A., Ferrier, E., Jacquelin, E., and Hamelin, P., “Analysis and modelling of the in-plane shear
behaviour of hollow brick masonry panels”, Construction and Building Materials, Vol. 20, pp. 308–321,
2006.
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