INVESTIGATION OF MATERIAL PROPERTIES FOR THE TURKISH MASONRY BUILDINGS ADİL BARAN ÇOBANOĞLU AUGUST 2014
INVESTIGATION OF MATERIAL PROPERTIES FOR THE TURKISH MASONRY BUILDINGS
Apr 01, 2023
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MASONRY BUILDINGS
MASONRY BUILDINGS
OF
FOR
IN
MASONRY BUILDINGS
Submitted by ADL BARAN ÇOBANOLU in partial fulfillment of the
requirements for the degree of Master of Science in Civil Engineering Department,
Middle EastTechnical University by,
Prof. Dr. Canan Özgen
Prof. Dr. Ahmet Cevdet Yalçner
Head of Department, Civil Engineering
Prof. Dr. Bar Binici
Examining Committee Members
Civil Engineering Dept., METU
Civil Engineering Dept., METU
Date: 29.08.2014
iv
I hereby declare that all information in this document has been obtained and
presented in accordance with academic rules and ethical conduct. I also declare
that, as required by these rules and conduct, I have fully cited and referenced all
material and results that are not original to this work.
Name, Last name: Adil Baran, Çobanolu
Signature :
v
ABSTRACT
MASONRY BUILDINGS
August 2014, 100 pages
Unreinforced masonry construction is still widespread among many urban and rural
areas, in developing countries such as Turkey. In order to prevent any loss of lives
during an earthquake, ensuring the safety of these buildings is crucial. The buildings
which are located in earthquake prone regions should be investigated and assessed so
that necessary precautions can be taken. Therefore, several questions and concerns
regarding the application of the assessment procedure, the assumptions and risk
decision for the current methods of masonry building assessment are raised.
This thesis addresses these concerns and investigates the material characteristics of
masonry buildings in Turkey and its effect on assessment methods. In this regard, ten
buildings were selected for the study and detailed information were collected on the
field regarding the selected buildings. After that, preliminary assessments were
conducted on the selected buildings according to the method described in RBTEIE
(2013) and the results were evaluated. Then, axial compression, diagonal tension and
sliding shear tests were conducted in the laboratory, on the wall specimens obtained
from the selected buildings. The test results were discussed along with the comparison
vi
with the strength values given in TEC (2007) and new material characteristics for
masonry buildings were recommended accordingly. Finally, assessment methods
described in TEC (2007) and RBTEIE (2013) were conducted to the selected buildings
with different material characteristics for all the earthquake zones. The assessment
results showed that, the assessments conducted with the allowable stress values
provided by TEC (2007) might lead to inaccurate and unsafe results.
Keywords: Masonry, Material Properties, Assessment
vii
ÖZ
NCELENMES
Tez Yöneticisi : Prof. Dr. Bar Binici
Austos 2014, 100 sayfa
Donatsz yma yaplar, Türkiye gibi gelien ülkerlerin kentsel ve krsal alanlarnda
hala yaygn olarak kullanlmaktadr. Olas bir deprem durumunda can kaybn önlemek
adna bu gibi binalarn güvenliini salamak çok önemlidir. Bu yüzden, ileri deprem
bölgelerindeki binalarn incelenip deerlendirilmesi ve gerekli önlemlerin alnmas
arttr. Bu balamda binalarn deerlendirilmesi ve deerlendirme srasnda yaplan
varsaymlar hakknda çeitli sorular ve endieler ortaya çkmaktadr.
Bu tez, belirtilen endieleri ele alarak Türkiye’deki yma yaplarn malzeme
özelliklerini inceleyip bu özelliklerin risk deerlendirme methodlar üzerindeki
etkisini aratrmaktadr. Bu kapsamda, çalma için on bina seçilmi ve binalar
hakknda detayl bilgi saha çalmalaryla toplanmtr. Öncelikle bütün binalar için
RBTEIE’de belirtilen yöntemle (2013) ön deerlendirme yaplmtr ve sonuçlar
irdelenmitir. Daha sonra, laboratuar ortamnda sahadan alnan numuneler üstünde
eksenel basnç, diyagonal çekme ve kayma deneyleri yaplmtr. Deney sonuçlar,
DBYBHY’de (2007) verilen dayanm deerleriyle karlatrlarak incelenmi ve yeni
viii
malzeme özellikleri önerilmitir. Son olarak, seçilen binalarn farkl malzeme
özellikleri ve farkl deprem bölgeleri için DBYBHY (2007) ve RBTEIE’de (2013)
belirtilen yöntemle detayl deerlendirmeleri yaplmtr. Deerlendirme sonuçlar,
DBYBHY’de (2007) verilen malzeme özellikleri kullanldnda hatal ve güvenli
olmayan sonuçlarn ortaya çkabilieceini göstermektedir.
Anahtar Kelimeler: Yma Bina, Malzeme Özellikleri, Risk Deerlendirmesi
ix
x
ACKNOWLEDGEMENTS
This study was carried out under the supervision of Prof. Dr. Bar Binici and I would
like to express my deepest gratitude to him for his support, guidance, criticism,
patience, encouragement throughout this study and above all, for not giving up on me.
This thesis benefited from the invaluable suggestions of Assoc. Prof. Dr. Erdem
Canbay and I would like to thank him for sharing his insight and experiences. I am
grateful to all M.S. examination committee members Prof. Dr. Ahmet Yakut, Prof.
smail Özgür Yaman and Asst. Prof. Dr. Ramazan Özçelik for their positive feedback.
I would like to thank the Ministry of Environment and Urbanization for their support.
I would like to express my gratitude to Hasan Metin, who taught everything I know in
the structural mechanics laboratory. I am also grateful to our technicians in structural
mechanics laboratory for their help throughout this study.
I would like to thank my roommates Alper Aldemir, smail Ozan Demirel and Erhan
Budak for their help and friendship. I felt lucky working with such great colleagues.
I would like to thank specially to ‘Ankara Crew’: Miran Dzabic, Pnar Berberolu,
Ylgün Gürcan, Onur Can Sert, Su Ertürkmen, Cihan imek, Murat Ayhan, Sinem
Laçin and Selçuk Öksüz for their great moral support and friendship through this
challenging process. I have been very fortunate to have such amazing friends.
I would also like to thank my dear friends Egemen Çam, Ece Boyacolu, Çaatay
Hanedan, Bar Hackerimolu, Kayra Ergen, Erturul Gören, lke Gören, Ufuk
Çalkan, Tuçe Güney, Nilay Doulu and Ava Bagherpoor for their invaluable
friendship throughout the years.
I owe a special thanks to Oya Memlük, who was there for me when I needed the most.
Thank you so much for everything.
Last but upmost, I would like to thank my whole family and especially my parents
Aye and Sezai Çobanolu to whom this thesis is dedicated to. It would not be possible
to finish this thesis without their love and endless support.
xi
2 BUILDING INFORMATION ....................................................................... 11
2.3 Preliminary Assesment of the Buildings ................................................. 33
3 MATERIAL TESTING ................................................................................. 35
3.2 Laboratory Tests ...................................................................................... 36
3.2.1 Compression Tests ........................................................................... 38
3.3 Discussion of Results and Recommendations ......................................... 80
xii
EXAMINED BUILDINGS .................................................................................... 85
4.1 General ..................................................................................................... 85
4.2 Assessment Method of Masonry Buildings described in RBTEIE (2013)
and TEC (2007) .................................................................................................. 86
5 CONCLUSION .............................................................................................. 95
5.1 Summary .................................................................................................. 95
5.2 Conclusions .............................................................................................. 96
Table 2.2 Detailed information about Building 1 ...................................................... 14
Table 2.3 Detailed information about Building 2 ...................................................... 16
Table 2.4 Detailed information about Building 3 ...................................................... 18
Table 2.5 Detailed information about Building 4 ...................................................... 20
Table 2.6 Detailed information about Building 5 ...................................................... 22
Table 2.7 Detailed information about Building 6 ...................................................... 24
Table 2.8 Detailed information about Building 7 ...................................................... 26
Table 2.9 Detailed information about Building 8 ...................................................... 28
Table 2.10 Detailed information about Building 9 .................................................... 30
Table 2.11 Detailed information about Building 10 .................................................. 32
Table 2.12 Preliminary assessment results................................................................. 34
Table 3.1 Test results ................................................................................................. 59
Table 3.2 Allowable compressive stress values of walls (TEC, 2007) ...................... 80
Table 3.3 Allowable shear stress values of walls (TEC, 2007) ................................. 80
Table 3.4 Comparison of test results with the values given in TEC (2007) .............. 81
Table 3.5 Recommended strength values based on masonry unit types .................... 82
Table 4.1 Material strengths used for the assessment ................................................ 88
Table 4.2 Assessment results consdering the buildings’ actual earthquake zone ...... 89
Table 4.3 Assessment results using the material strengths from the laboratory tests 90
Table 4.4 Assessment results using the material strengths provided by TEC (2007) 90
Table 4.5 Assessment results using the recommended material strengths................. 90
Figure 3.1 Examples from specimen removal process ............................................... 36
Figure 3.2 Displacement based test machine ............................................................. 37
Figure 3.3 Axial compression test setup .................................................................... 39
Figure 3.4 Building 1 compression test results along the axis parallel to the load
bearing direction of the wall ....................................................................................... 41
Figure 3.5 Building 1 compression test results along the axis parallel to the load
bearing direction of the wall ....................................................................................... 42
Figure 3.6 Building 1 compression test results along the axis perpendicular to the load
bearing direction of the wall ....................................................................................... 43
Figure 3.7 Building 2 compression test results along the axis parallel to the load
bearing direction of the wall ....................................................................................... 44
Figure 3.8 Building 2 compression test results along the axis perpendicular to the load
bearing direction of the wall ....................................................................................... 45
Figure 3.9 Building 3 compression test results along the axis parallel to the load
bearing direction of the wall ....................................................................................... 46
xv
Figure 3.10 Building 3 compression test results along the axis perpendicular to the load
bearing direction of the wall ...................................................................................... 47
Figure 3.11 Building 4 compression test results along the axis parallel to the load
bearing direction of the wall ...................................................................................... 48
Figure 3.12 Building 4 compression test results along the axis perpendicular to the load
bearing direction of the wall ...................................................................................... 49
Figure 3.13 Building 5 compression test results along the axis parallel to the load
bearing direction of the wall (Cellular concrete block) ............................................. 50
Figure 3.14 Building 5 compression test results along the axis parallel to the load
bearing direction of the wall (Adobe) ........................................................................ 51
Figure 3.15 Building 6 compression test results along the axis parallel to the load
bearing direction of the wall ...................................................................................... 52
Figure 3.16 Building 6 compression test results along the axis perpendicular to the load
bearing direction of the wall ...................................................................................... 53
Figure 3.17 Building 7 compression test result along the axis parallel to the load
bearing direction of the wall ...................................................................................... 54
Figure 3.18 Building 8 compression test results along the axis parallel to the load
bearing direction of the wall ...................................................................................... 55
Figure 3.19 Building 9 compression test results along the axis parallel to the load
bearing direction of the wall ...................................................................................... 56
Figure 3.20 Building 9 compression test results along the axis perpendicular to the load
bearing direction of the wall ...................................................................................... 57
Figure 3.21 Building 10 compression test results along the axis parallel to the load
bearing direction of the wall ...................................................................................... 58
Figure 3.22 Steel loading shoe ................................................................................... 60
Figure 3.23 Diagonal tension test setup ..................................................................... 61
Figure 3.24 Building 1 diagonal tension test results .................................................. 63
Figure 3.25 Building 2 diagonal tension test results .................................................. 64
Figure 3.26 Building 3 diagonal tension test results .................................................. 65
Figure 3.27 Building 4 diagonal tension test result ................................................... 66
Figure 3.28 Building 5 diagonal tension test results .................................................. 67
Figure 3.29 Building 6 diagonal tension test results .................................................. 68
xvi
Figure 3.30 Building 7 diagonal tension test result .................................................... 69
Figure 3.31 Building 8 diagonal tension test result .................................................... 70
Figure 3.32 Building 9 diagonal tension test results .................................................. 71
Figure 3.33 Building 10 diagonal tension test result .................................................. 72
Figure 3.34 The cutting of the cap to eliminate its contribution to shear strength ..... 73
Figure 3.35 Sliding shear test setup ........................................................................... 74
Figure 3.36 Building 1 triplet test results ................................................................... 75
Figure 3.37 Building 2 triplet test results ................................................................... 75
Figure 3.38 Building 3 triplet test results ................................................................... 76
Figure 3.39 Building 4 triplet test results ................................................................... 76
Figure 3.40 Building 6 triplet test results ................................................................... 77
Figure 3.41 Building 7 triplet test results ................................................................... 77
Figure 3.42 Building 8 triplet test results ................................................................... 78
Figure 3.43 Building 9 triplet test results ................................................................... 78
Figure 3.44 Building 10 triplet test results ................................................................. 79
Figure 3.45 Relationship between shear strength and compressive strength ............. 83
Figure 3.46 Relationship between diagonal tension strength and compressive strength
.................................................................................................................................... 83
Figure 3.47 Relationship between the modulus of elasticity and compressive strength
.................................................................................................................................... 84
1
CHAPTER 1
1 INTRODUCTION
1.1 Introduction
From the beginning of the civilized human life, one of the most basic needs had been
sheltering. It had been essential for people in terms of protection from both the wild
life and the nature. Being the only construction alternative at the time, masonry
construction had been the easiest way to fulfill the need. From simple cottages to
complex structures, the use of unreinforced masonry governed the construction
industry through centuries.
Contemporarily, unreinforced masonry (URM) construction is still widespread among
urban and rural areas. Due to the reasons such as the availability and durability of
materials, low cost and maintenance, reasonable insulation performance and most
importantly, constructing with little engineering knowledge enabled masonry
construction to maintain its popularity, especially for residential buildings (Hendry,
2001). Most of the residential building stock is composed of masonry structures all
over the world. In developing countries such as Turkey, the amount of masonry
construction was quite high in the midst of 20th century and started decreasing towards
the end of the century. A report prepared by the Housing Development Administration
of Turkey states that in urban areas, 48% of all buildings are brick masonry or timber
framed, while 30% of them are reinforced concrete frame type, and 22% are made
from adobe or rubble masonry. In rural areas the rate of any kind of masonry buildings
for housing increases to 82% (Erdik and Aydnolu, 2002).
2
Although masonry construction is widespread among many areas, it comes with
several drawbacks. According to Arya et.al, (1986) most of the masonry construction
is conducted without any engineering knowledge and guidance. Since more than 90%
of the population in the Middle East is still living and working on such buildings that
are in the moderate or severe seismic zones as exhibited by the past experience most
of the live losses occurred due to the collapse of such buildings during earthquakes
such as Elaz (Turkey, 2010), Bam (Iran, 2003) and Kashmir (Pakistan, 2005)
earthquakes. The rising population in the developing countries along with deficiency
of traditional building materials and construction techniques, lack of awareness and
necessary skills, are the main causes of the risk to the human life especially in
developing countries.
In this retrospect, ensuring the safety of these buildings during an earthquake is crucial
in order to prevent any loss of lives. The buildings that are located in earthquake prone
regions, should be investigated and assessed so that necessary precautions can be taken
beforehand. Depending on the assessment results, the buildings that are under high
earthquake risk should either be strengthened to resist expected earthquakes in that
region or renewed completely.
After the devastating earthquakes that resulted with the loss of thousands of lives in
Turkey, the importance given to the assessment and renewal of existing masonry
buildings increased dramatically. The implementation of new codes Turkish
Earthquake Code (TEC, 2007) and Guidelines for the Assessment of Buildings under
High Risk (RBTEIE, 2013) as per Law no. 6306 gave a better understanding for the
assessment of existing structures. In these documents, the assessment techniques for
existing reinforced concrete buildings are provided in details whereas the assessment
of masonry buildings are conducted with rather less accurate and more primitive
methods. The assessment process often results with the renewal of the existing
buildings and urban renewal projects became widespread along the country due to the
economical benefits rather than the consciousness of reducing seismic risk, which in
turn is the achieved objective. The popularity of the urban renewal projects, increased
the importance of the assessment methods, while raising several questions and
concerns regarding the application of the procedure, the assumptions and risk decision
for the current methods of masonry building assessment.
3
One of the main concerns about the assessment procedure for an existing masonry
building is the determination of the material properties while assessing the capacity of
the walls. A better understanding of the material characteristics of masonry is essential
since it may lead to more accurate assessment results. At this point, TEC (2007)
provides allowable stress values to be used if the capacity values cannot be obtained
through experiments conducted on the existing building. TEC (2007) recommended
values which depend on the masonry type. Unit compressive strength and mortar class
are specified, while the allowable compressive and shear strength values of walls are
also presented depending on the masonry unit type. Currently, those tabularized
allowable stress values are used as the material strength values in the assessment of all
of the existing masonry buildings. This situation obviously calls for a detailed
investigation of the accuracy and safety of the reported material strength values.
1.2 Literature Review
Many researchers studied masonry material characteristics, their correlation to each
other and factors affecting these properties. The easiest method to determine the
material characteristics of masonry is to perform appropriate laboratory tests on
specimens constructed with the exact same ingredients that are used on the building
site. Although this method provides reliable test results, the accuracy and possibility
of finding such specimens are questionable for existing masonry buildings. Therefore,
conducting experiments on specimens obtained from actual buildings provide a better
understanding of the material properties of existing buildings. There are numerous
publications on testing of masonry walls to obtain material strength along with many
numerical simulation results with various levels of sophistication. A brief review of
the literature conducted on both laboratory and in-situ material tests of masonry walls
are discussed in the following paragraphs.
Several codes implement methods to determine the material characteristics of the
masonry walls. For the determination of the compressive strength, FEMA 356 (2000)
and Eurocode 6 (2005) recommends to use one of the following methods: i)testing of
prisms that are extracted from the existing walls, ii) testing of prisms that are fabricated
4
from actual extracted masonry units or iii) estimating the compressive strength using
flatjack compression tests. If none of the tests are available, FEMA 356 (2000)
provides default lower bound compressive strength values varying between 2.1 MPa
and 6.2 MPa depending on the quality of the masonry condition, while Eurocode 6
(2005) gives equations based on the masonry unit and mortar to calculate the
compressive strength of masonry. In order to determine the shear strength of masonry
walls, both FEMA 356 (2000) and Eurocode 6 (2005) recommends to use an in-situ
shear test. If the test is not applicable, FEMA 356 (2000) provides default lower bound
shear strength values varying between 0.09 MPa and and 0.16 MPa depending on the
observed masonry condition. On the other hand, Eurocode 6 provides shear strength
values depending on masonry unit and mortar class that varies from 0.10 MPa to 0.30
MPa.
Gumaste et al., (2006) investigated the properties of brick masonry using 2 types of
bricks from India with various types of mortars. The strength and elastic modulus of
brick masonry under compression were evaluated. In order to observe the size effect
and different bonding arrangements, various sizes of prisms and wallettes were tested
and the failure mechanisms were observed. Combination of four types of masonry
specimens using table moulded bricks and wire-cut bricks with three different types of
mortar were tested. The compressive strength values varied between 0.67 MPa and
3.18 MPa for the moulded brick masonry while the compressive strength varied
between 5.3 MPa and 14.9 MPa for the wire-cut brick masonry. For the first type of
specimens the modulus of elasticity varied between 260 and 735 MPa. On the other
hand, the modulus of elasticity values were observed in a range of 2393-5232 MPa.
Different failure modes were observed between different types of specimens.
Empirical relationships for masonry strength depending on brick and mortar strength
were derived as the main result of the study.
Russell (2010), studied the characterization and seismic assessment of unreinforced
masonry buildings in order to develop a better understanding of the response of URM
buildings. During the study, Russell (2010), also investigated the diagonal tension
(shear) strength of unreinforced masonry having different mortar properties and bond
patterns. A total of nine diagonal tension tests were conducted and the results showed
that the capacities were between 0.04 MPa and 0.5 MPa. Even when the mortar type
5
and other variables were kept constant, the results indicated a significant variation in
the diagonal tension strength of the wall panels. The modulus of elasticity values were
also reported and they varied from 1960 MPa to 2560 MPa. These experiment results
along with some other…
MASONRY BUILDINGS
OF
FOR
IN
MASONRY BUILDINGS
Submitted by ADL BARAN ÇOBANOLU in partial fulfillment of the
requirements for the degree of Master of Science in Civil Engineering Department,
Middle EastTechnical University by,
Prof. Dr. Canan Özgen
Prof. Dr. Ahmet Cevdet Yalçner
Head of Department, Civil Engineering
Prof. Dr. Bar Binici
Examining Committee Members
Civil Engineering Dept., METU
Civil Engineering Dept., METU
Date: 29.08.2014
iv
I hereby declare that all information in this document has been obtained and
presented in accordance with academic rules and ethical conduct. I also declare
that, as required by these rules and conduct, I have fully cited and referenced all
material and results that are not original to this work.
Name, Last name: Adil Baran, Çobanolu
Signature :
v
ABSTRACT
MASONRY BUILDINGS
August 2014, 100 pages
Unreinforced masonry construction is still widespread among many urban and rural
areas, in developing countries such as Turkey. In order to prevent any loss of lives
during an earthquake, ensuring the safety of these buildings is crucial. The buildings
which are located in earthquake prone regions should be investigated and assessed so
that necessary precautions can be taken. Therefore, several questions and concerns
regarding the application of the assessment procedure, the assumptions and risk
decision for the current methods of masonry building assessment are raised.
This thesis addresses these concerns and investigates the material characteristics of
masonry buildings in Turkey and its effect on assessment methods. In this regard, ten
buildings were selected for the study and detailed information were collected on the
field regarding the selected buildings. After that, preliminary assessments were
conducted on the selected buildings according to the method described in RBTEIE
(2013) and the results were evaluated. Then, axial compression, diagonal tension and
sliding shear tests were conducted in the laboratory, on the wall specimens obtained
from the selected buildings. The test results were discussed along with the comparison
vi
with the strength values given in TEC (2007) and new material characteristics for
masonry buildings were recommended accordingly. Finally, assessment methods
described in TEC (2007) and RBTEIE (2013) were conducted to the selected buildings
with different material characteristics for all the earthquake zones. The assessment
results showed that, the assessments conducted with the allowable stress values
provided by TEC (2007) might lead to inaccurate and unsafe results.
Keywords: Masonry, Material Properties, Assessment
vii
ÖZ
NCELENMES
Tez Yöneticisi : Prof. Dr. Bar Binici
Austos 2014, 100 sayfa
Donatsz yma yaplar, Türkiye gibi gelien ülkerlerin kentsel ve krsal alanlarnda
hala yaygn olarak kullanlmaktadr. Olas bir deprem durumunda can kaybn önlemek
adna bu gibi binalarn güvenliini salamak çok önemlidir. Bu yüzden, ileri deprem
bölgelerindeki binalarn incelenip deerlendirilmesi ve gerekli önlemlerin alnmas
arttr. Bu balamda binalarn deerlendirilmesi ve deerlendirme srasnda yaplan
varsaymlar hakknda çeitli sorular ve endieler ortaya çkmaktadr.
Bu tez, belirtilen endieleri ele alarak Türkiye’deki yma yaplarn malzeme
özelliklerini inceleyip bu özelliklerin risk deerlendirme methodlar üzerindeki
etkisini aratrmaktadr. Bu kapsamda, çalma için on bina seçilmi ve binalar
hakknda detayl bilgi saha çalmalaryla toplanmtr. Öncelikle bütün binalar için
RBTEIE’de belirtilen yöntemle (2013) ön deerlendirme yaplmtr ve sonuçlar
irdelenmitir. Daha sonra, laboratuar ortamnda sahadan alnan numuneler üstünde
eksenel basnç, diyagonal çekme ve kayma deneyleri yaplmtr. Deney sonuçlar,
DBYBHY’de (2007) verilen dayanm deerleriyle karlatrlarak incelenmi ve yeni
viii
malzeme özellikleri önerilmitir. Son olarak, seçilen binalarn farkl malzeme
özellikleri ve farkl deprem bölgeleri için DBYBHY (2007) ve RBTEIE’de (2013)
belirtilen yöntemle detayl deerlendirmeleri yaplmtr. Deerlendirme sonuçlar,
DBYBHY’de (2007) verilen malzeme özellikleri kullanldnda hatal ve güvenli
olmayan sonuçlarn ortaya çkabilieceini göstermektedir.
Anahtar Kelimeler: Yma Bina, Malzeme Özellikleri, Risk Deerlendirmesi
ix
x
ACKNOWLEDGEMENTS
This study was carried out under the supervision of Prof. Dr. Bar Binici and I would
like to express my deepest gratitude to him for his support, guidance, criticism,
patience, encouragement throughout this study and above all, for not giving up on me.
This thesis benefited from the invaluable suggestions of Assoc. Prof. Dr. Erdem
Canbay and I would like to thank him for sharing his insight and experiences. I am
grateful to all M.S. examination committee members Prof. Dr. Ahmet Yakut, Prof.
smail Özgür Yaman and Asst. Prof. Dr. Ramazan Özçelik for their positive feedback.
I would like to thank the Ministry of Environment and Urbanization for their support.
I would like to express my gratitude to Hasan Metin, who taught everything I know in
the structural mechanics laboratory. I am also grateful to our technicians in structural
mechanics laboratory for their help throughout this study.
I would like to thank my roommates Alper Aldemir, smail Ozan Demirel and Erhan
Budak for their help and friendship. I felt lucky working with such great colleagues.
I would like to thank specially to ‘Ankara Crew’: Miran Dzabic, Pnar Berberolu,
Ylgün Gürcan, Onur Can Sert, Su Ertürkmen, Cihan imek, Murat Ayhan, Sinem
Laçin and Selçuk Öksüz for their great moral support and friendship through this
challenging process. I have been very fortunate to have such amazing friends.
I would also like to thank my dear friends Egemen Çam, Ece Boyacolu, Çaatay
Hanedan, Bar Hackerimolu, Kayra Ergen, Erturul Gören, lke Gören, Ufuk
Çalkan, Tuçe Güney, Nilay Doulu and Ava Bagherpoor for their invaluable
friendship throughout the years.
I owe a special thanks to Oya Memlük, who was there for me when I needed the most.
Thank you so much for everything.
Last but upmost, I would like to thank my whole family and especially my parents
Aye and Sezai Çobanolu to whom this thesis is dedicated to. It would not be possible
to finish this thesis without their love and endless support.
xi
2 BUILDING INFORMATION ....................................................................... 11
2.3 Preliminary Assesment of the Buildings ................................................. 33
3 MATERIAL TESTING ................................................................................. 35
3.2 Laboratory Tests ...................................................................................... 36
3.2.1 Compression Tests ........................................................................... 38
3.3 Discussion of Results and Recommendations ......................................... 80
xii
EXAMINED BUILDINGS .................................................................................... 85
4.1 General ..................................................................................................... 85
4.2 Assessment Method of Masonry Buildings described in RBTEIE (2013)
and TEC (2007) .................................................................................................. 86
5 CONCLUSION .............................................................................................. 95
5.1 Summary .................................................................................................. 95
5.2 Conclusions .............................................................................................. 96
Table 2.2 Detailed information about Building 1 ...................................................... 14
Table 2.3 Detailed information about Building 2 ...................................................... 16
Table 2.4 Detailed information about Building 3 ...................................................... 18
Table 2.5 Detailed information about Building 4 ...................................................... 20
Table 2.6 Detailed information about Building 5 ...................................................... 22
Table 2.7 Detailed information about Building 6 ...................................................... 24
Table 2.8 Detailed information about Building 7 ...................................................... 26
Table 2.9 Detailed information about Building 8 ...................................................... 28
Table 2.10 Detailed information about Building 9 .................................................... 30
Table 2.11 Detailed information about Building 10 .................................................. 32
Table 2.12 Preliminary assessment results................................................................. 34
Table 3.1 Test results ................................................................................................. 59
Table 3.2 Allowable compressive stress values of walls (TEC, 2007) ...................... 80
Table 3.3 Allowable shear stress values of walls (TEC, 2007) ................................. 80
Table 3.4 Comparison of test results with the values given in TEC (2007) .............. 81
Table 3.5 Recommended strength values based on masonry unit types .................... 82
Table 4.1 Material strengths used for the assessment ................................................ 88
Table 4.2 Assessment results consdering the buildings’ actual earthquake zone ...... 89
Table 4.3 Assessment results using the material strengths from the laboratory tests 90
Table 4.4 Assessment results using the material strengths provided by TEC (2007) 90
Table 4.5 Assessment results using the recommended material strengths................. 90
Figure 3.1 Examples from specimen removal process ............................................... 36
Figure 3.2 Displacement based test machine ............................................................. 37
Figure 3.3 Axial compression test setup .................................................................... 39
Figure 3.4 Building 1 compression test results along the axis parallel to the load
bearing direction of the wall ....................................................................................... 41
Figure 3.5 Building 1 compression test results along the axis parallel to the load
bearing direction of the wall ....................................................................................... 42
Figure 3.6 Building 1 compression test results along the axis perpendicular to the load
bearing direction of the wall ....................................................................................... 43
Figure 3.7 Building 2 compression test results along the axis parallel to the load
bearing direction of the wall ....................................................................................... 44
Figure 3.8 Building 2 compression test results along the axis perpendicular to the load
bearing direction of the wall ....................................................................................... 45
Figure 3.9 Building 3 compression test results along the axis parallel to the load
bearing direction of the wall ....................................................................................... 46
xv
Figure 3.10 Building 3 compression test results along the axis perpendicular to the load
bearing direction of the wall ...................................................................................... 47
Figure 3.11 Building 4 compression test results along the axis parallel to the load
bearing direction of the wall ...................................................................................... 48
Figure 3.12 Building 4 compression test results along the axis perpendicular to the load
bearing direction of the wall ...................................................................................... 49
Figure 3.13 Building 5 compression test results along the axis parallel to the load
bearing direction of the wall (Cellular concrete block) ............................................. 50
Figure 3.14 Building 5 compression test results along the axis parallel to the load
bearing direction of the wall (Adobe) ........................................................................ 51
Figure 3.15 Building 6 compression test results along the axis parallel to the load
bearing direction of the wall ...................................................................................... 52
Figure 3.16 Building 6 compression test results along the axis perpendicular to the load
bearing direction of the wall ...................................................................................... 53
Figure 3.17 Building 7 compression test result along the axis parallel to the load
bearing direction of the wall ...................................................................................... 54
Figure 3.18 Building 8 compression test results along the axis parallel to the load
bearing direction of the wall ...................................................................................... 55
Figure 3.19 Building 9 compression test results along the axis parallel to the load
bearing direction of the wall ...................................................................................... 56
Figure 3.20 Building 9 compression test results along the axis perpendicular to the load
bearing direction of the wall ...................................................................................... 57
Figure 3.21 Building 10 compression test results along the axis parallel to the load
bearing direction of the wall ...................................................................................... 58
Figure 3.22 Steel loading shoe ................................................................................... 60
Figure 3.23 Diagonal tension test setup ..................................................................... 61
Figure 3.24 Building 1 diagonal tension test results .................................................. 63
Figure 3.25 Building 2 diagonal tension test results .................................................. 64
Figure 3.26 Building 3 diagonal tension test results .................................................. 65
Figure 3.27 Building 4 diagonal tension test result ................................................... 66
Figure 3.28 Building 5 diagonal tension test results .................................................. 67
Figure 3.29 Building 6 diagonal tension test results .................................................. 68
xvi
Figure 3.30 Building 7 diagonal tension test result .................................................... 69
Figure 3.31 Building 8 diagonal tension test result .................................................... 70
Figure 3.32 Building 9 diagonal tension test results .................................................. 71
Figure 3.33 Building 10 diagonal tension test result .................................................. 72
Figure 3.34 The cutting of the cap to eliminate its contribution to shear strength ..... 73
Figure 3.35 Sliding shear test setup ........................................................................... 74
Figure 3.36 Building 1 triplet test results ................................................................... 75
Figure 3.37 Building 2 triplet test results ................................................................... 75
Figure 3.38 Building 3 triplet test results ................................................................... 76
Figure 3.39 Building 4 triplet test results ................................................................... 76
Figure 3.40 Building 6 triplet test results ................................................................... 77
Figure 3.41 Building 7 triplet test results ................................................................... 77
Figure 3.42 Building 8 triplet test results ................................................................... 78
Figure 3.43 Building 9 triplet test results ................................................................... 78
Figure 3.44 Building 10 triplet test results ................................................................. 79
Figure 3.45 Relationship between shear strength and compressive strength ............. 83
Figure 3.46 Relationship between diagonal tension strength and compressive strength
.................................................................................................................................... 83
Figure 3.47 Relationship between the modulus of elasticity and compressive strength
.................................................................................................................................... 84
1
CHAPTER 1
1 INTRODUCTION
1.1 Introduction
From the beginning of the civilized human life, one of the most basic needs had been
sheltering. It had been essential for people in terms of protection from both the wild
life and the nature. Being the only construction alternative at the time, masonry
construction had been the easiest way to fulfill the need. From simple cottages to
complex structures, the use of unreinforced masonry governed the construction
industry through centuries.
Contemporarily, unreinforced masonry (URM) construction is still widespread among
urban and rural areas. Due to the reasons such as the availability and durability of
materials, low cost and maintenance, reasonable insulation performance and most
importantly, constructing with little engineering knowledge enabled masonry
construction to maintain its popularity, especially for residential buildings (Hendry,
2001). Most of the residential building stock is composed of masonry structures all
over the world. In developing countries such as Turkey, the amount of masonry
construction was quite high in the midst of 20th century and started decreasing towards
the end of the century. A report prepared by the Housing Development Administration
of Turkey states that in urban areas, 48% of all buildings are brick masonry or timber
framed, while 30% of them are reinforced concrete frame type, and 22% are made
from adobe or rubble masonry. In rural areas the rate of any kind of masonry buildings
for housing increases to 82% (Erdik and Aydnolu, 2002).
2
Although masonry construction is widespread among many areas, it comes with
several drawbacks. According to Arya et.al, (1986) most of the masonry construction
is conducted without any engineering knowledge and guidance. Since more than 90%
of the population in the Middle East is still living and working on such buildings that
are in the moderate or severe seismic zones as exhibited by the past experience most
of the live losses occurred due to the collapse of such buildings during earthquakes
such as Elaz (Turkey, 2010), Bam (Iran, 2003) and Kashmir (Pakistan, 2005)
earthquakes. The rising population in the developing countries along with deficiency
of traditional building materials and construction techniques, lack of awareness and
necessary skills, are the main causes of the risk to the human life especially in
developing countries.
In this retrospect, ensuring the safety of these buildings during an earthquake is crucial
in order to prevent any loss of lives. The buildings that are located in earthquake prone
regions, should be investigated and assessed so that necessary precautions can be taken
beforehand. Depending on the assessment results, the buildings that are under high
earthquake risk should either be strengthened to resist expected earthquakes in that
region or renewed completely.
After the devastating earthquakes that resulted with the loss of thousands of lives in
Turkey, the importance given to the assessment and renewal of existing masonry
buildings increased dramatically. The implementation of new codes Turkish
Earthquake Code (TEC, 2007) and Guidelines for the Assessment of Buildings under
High Risk (RBTEIE, 2013) as per Law no. 6306 gave a better understanding for the
assessment of existing structures. In these documents, the assessment techniques for
existing reinforced concrete buildings are provided in details whereas the assessment
of masonry buildings are conducted with rather less accurate and more primitive
methods. The assessment process often results with the renewal of the existing
buildings and urban renewal projects became widespread along the country due to the
economical benefits rather than the consciousness of reducing seismic risk, which in
turn is the achieved objective. The popularity of the urban renewal projects, increased
the importance of the assessment methods, while raising several questions and
concerns regarding the application of the procedure, the assumptions and risk decision
for the current methods of masonry building assessment.
3
One of the main concerns about the assessment procedure for an existing masonry
building is the determination of the material properties while assessing the capacity of
the walls. A better understanding of the material characteristics of masonry is essential
since it may lead to more accurate assessment results. At this point, TEC (2007)
provides allowable stress values to be used if the capacity values cannot be obtained
through experiments conducted on the existing building. TEC (2007) recommended
values which depend on the masonry type. Unit compressive strength and mortar class
are specified, while the allowable compressive and shear strength values of walls are
also presented depending on the masonry unit type. Currently, those tabularized
allowable stress values are used as the material strength values in the assessment of all
of the existing masonry buildings. This situation obviously calls for a detailed
investigation of the accuracy and safety of the reported material strength values.
1.2 Literature Review
Many researchers studied masonry material characteristics, their correlation to each
other and factors affecting these properties. The easiest method to determine the
material characteristics of masonry is to perform appropriate laboratory tests on
specimens constructed with the exact same ingredients that are used on the building
site. Although this method provides reliable test results, the accuracy and possibility
of finding such specimens are questionable for existing masonry buildings. Therefore,
conducting experiments on specimens obtained from actual buildings provide a better
understanding of the material properties of existing buildings. There are numerous
publications on testing of masonry walls to obtain material strength along with many
numerical simulation results with various levels of sophistication. A brief review of
the literature conducted on both laboratory and in-situ material tests of masonry walls
are discussed in the following paragraphs.
Several codes implement methods to determine the material characteristics of the
masonry walls. For the determination of the compressive strength, FEMA 356 (2000)
and Eurocode 6 (2005) recommends to use one of the following methods: i)testing of
prisms that are extracted from the existing walls, ii) testing of prisms that are fabricated
4
from actual extracted masonry units or iii) estimating the compressive strength using
flatjack compression tests. If none of the tests are available, FEMA 356 (2000)
provides default lower bound compressive strength values varying between 2.1 MPa
and 6.2 MPa depending on the quality of the masonry condition, while Eurocode 6
(2005) gives equations based on the masonry unit and mortar to calculate the
compressive strength of masonry. In order to determine the shear strength of masonry
walls, both FEMA 356 (2000) and Eurocode 6 (2005) recommends to use an in-situ
shear test. If the test is not applicable, FEMA 356 (2000) provides default lower bound
shear strength values varying between 0.09 MPa and and 0.16 MPa depending on the
observed masonry condition. On the other hand, Eurocode 6 provides shear strength
values depending on masonry unit and mortar class that varies from 0.10 MPa to 0.30
MPa.
Gumaste et al., (2006) investigated the properties of brick masonry using 2 types of
bricks from India with various types of mortars. The strength and elastic modulus of
brick masonry under compression were evaluated. In order to observe the size effect
and different bonding arrangements, various sizes of prisms and wallettes were tested
and the failure mechanisms were observed. Combination of four types of masonry
specimens using table moulded bricks and wire-cut bricks with three different types of
mortar were tested. The compressive strength values varied between 0.67 MPa and
3.18 MPa for the moulded brick masonry while the compressive strength varied
between 5.3 MPa and 14.9 MPa for the wire-cut brick masonry. For the first type of
specimens the modulus of elasticity varied between 260 and 735 MPa. On the other
hand, the modulus of elasticity values were observed in a range of 2393-5232 MPa.
Different failure modes were observed between different types of specimens.
Empirical relationships for masonry strength depending on brick and mortar strength
were derived as the main result of the study.
Russell (2010), studied the characterization and seismic assessment of unreinforced
masonry buildings in order to develop a better understanding of the response of URM
buildings. During the study, Russell (2010), also investigated the diagonal tension
(shear) strength of unreinforced masonry having different mortar properties and bond
patterns. A total of nine diagonal tension tests were conducted and the results showed
that the capacities were between 0.04 MPa and 0.5 MPa. Even when the mortar type
5
and other variables were kept constant, the results indicated a significant variation in
the diagonal tension strength of the wall panels. The modulus of elasticity values were
also reported and they varied from 1960 MPa to 2560 MPa. These experiment results
along with some other…
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