Symposium with International Participation on Strengthening and

Symposium with International Participation on Strengthening and

Symposium with International Participation on Strengthening and Preserving Historical
Buildings and Cultural Heritage – II, 15-17 October 2009, Diyarbakır, Turkey
SEISMIC PERFORMANCE EVALUATION OF
EMİR BAYINDIR CUPOLA IN AHLAT
Dilek Okuyucu1, Barış ERDİL2
Middle East Technical University, Ankara, Turkey
ABSTRACT
Cupola, in some cases termed as tomb, (kümbet in Turkish) is the special name for the
monumental mausoleum of a distinguished person in Turkish architecture. Ahlat town near
Lake Van is hosting a number of exotic cupolas dating back to even 12th century. The area is
somehow, denoted as first level of seismic zone in official Turkish Seismic Zoning Map. Emir
Bayındır Cupola in Ahlat is one of the spectacular examples of cupola type grave style. This
monument is reported not to have any structural evaluation and curing at least in the last four
decades; while it has some observable serious structural deterioration, cracks that can threaten
the monument during seismic excitations. Seismic performance of Emir Bayındır Cupola was
evaluated analytically within this perspective. Geometrical dimensions of the structure were
measured and in-situ, visual structural evaluations were performed first then the analysis was
performed. The main objective of the study is to take attention for special Turkish cupola
architecture and its open air museum, Ahlat. So that, a number of spectacular cupolas as well
as Seljukian grave stones, even dating back to early 12th century, in this land need structural
evaluation, protection, restoration and structural rehabilitation by means of cultural heritage
respect and transferring them to future. This manuscript provides information about Ahlat, its
cupolas and grave stones; then seismic performance evaluation and results of the analytical
study for Emir Bayındır Cupola.
Keywords: Cultural Heritage, Anatolia, Akkoyunlu Period, Cupola, Earthquake, Masonry
Seismic Evaluation, Macro Modeling, Seismic Strengthening.
1
2
PhD Candidate, METU, Ankara, Turkey & Res. Asst., Atatürk University, Erzurum, Turkey ([email protected])
PhD Candidate, METU, Ankara, Turkey & Res. Asst., Yüzüncü Yıl University, Van, Turkey ([email protected])
Uluslararası Katılımlı Tarihi Eserlerin Güçlendirilmesi ve Geleceğe Güvenle Devredilmesi
Sempozyumu – II, 15 - 17 Ekim 2009, Diyarbakır, Türkiye
AHLAT EMİR BAYINDIR KÜMBETİ DEPREM DAVRANIŞ ANALİZİ
Dilek OKUYUCU1, Barış ERDİL2
Orta Doğu Teknik Üniversitesi, Ankara, Türkiye
ÖZ
Kümbetler, Türk mimarisinde bir takım hizmet ve özellikleriyle toplumda öne çıkan insanlar
için yapılmış olan anıtsal mezarlardır. Van Gölü kenarında yer alan Ahlat, yapımı 12. yüzyıla
kadar tarihlenebilen çok sayıda özgün kümbete ev sahipliği yapmaktadır. Bununlar birlikte,
bölge Türkiye Deprem Bölgeleri Haritası’ nda 1. derece deprem bölgesi olarak ifade
edilmektedir. Yerinde yapılan incelemelerle, Ahlat’ taki bu önemli kültür mirasımızı korumak
ve gelecek nesillere devredilebilmek gayesiyle, bölgedeki çok sayıda kümbetin ve yine 12.
yüzyıl başlarına kadar tarihlenebilen, anıtsal nitelikli Selçuklu mezar taşlarının yapısal olarak
incelenmesi ve gerekli görülenlerin restorasyon, koruma ve yapısal güçlendirme
çalışmalarının yapılması gerekliliği kanısına varılmıştır. İlçedeki Emir Bayındır Kümbeti, bu
özel mezar yapısı türünün, mimari farklılılar açısından en dikkat çeken örneklerinden
birisidir. Yapıda gözle görülebilen ve olası yer hareketlerinde yapıyı tehdit edebileceği
düşünülebilecek hasarlar ve çatlaklar mevcut olmasına rağmen, son kırk yıl içerisinde
herhangi bir inceleme ya da onarım yapılmadığı ifade edilmiştir. Bu noktadan hareketle, Emir
Bayındır Kümbeti’ nin dinamik yükler altındaki davranışı analitik olarak incelenmiştir.
Öncelikli olarak, yapının geometrik boyutları ölçülmüş, genel durumu gözle yapılan inceleme
ile detaylandırılmış ve sonrasında deprem davranışı bilgisayar modeli üzerinde analitik olarak
incelenmiştir. Çalışmanın asıl amacı, çok özel bir Türk mimarisi ürünü olan kümbet
geleneğine ve bu bağlamda, açık hava kümbet müzesi niteliğindeki Ahlat bölgesine dikkat
çekmektir. Metinde öncelikli olarak Ahlat bölgesi kümbet ve mezar taşları hakkında bilgi
verilecek, Emir Bayındır Kümbeti için yapılmış olan yapısal analiz çalışmasının detay ve
sonuçları sunulacaktır.
Anahtar Kelimeler: Kültür Mirası, Anadolu, Akkoyunlu Dönemi, Kümbet, Deprem, Yığma,
Sismik Değerlendirme, Makro Modelleme, Sismik Güçlendirme
1
Doktor Adayı, ODTÜ, Ankara, Türkiye & Araştırma Görevlisi, Atatürk Üniversitesi, Erzurum, Türkiye. ([email protected])
2
Doktor Adayı, ODTÜ, Ankara, Türkiye & Araştırma Görevlisi, Yüzüncü Yıl Üniversitesi, Van Türkiye. ([email protected])
INTRODUCTION
Numerous civilizations survived on Anatolian land since the centuries, remaining their
fingerprints in forms of visual architectural products on the land area and cultural remains in
public life in forms of traditional applications. This multicolored, open air museum is,
unfortunately, located on one of the most active seismic zones of the earth. Seismic
excitations damage vulnerable existing buildings, somehow causing life losses on the
Anatolian Peninsula. This reality creates a need to protect our historical structures in the name
of cultural heritage respect. Historical buildings are basically made of brick and/or stone
masonry. In structural engineering perspective, masonry structures are very well known to be
quite vulnerable to seismic excitations. In order to carry our architectural-historical heritage to
the next generations by means of structural protection; seismic performance evaluation is first
needed and then, considering the evaluation results history-friendly seismic rehabilitation,
protection and proper restorations of ornaments, etc. are required to be applied for the
specified structure.
Emir Bayındır Cupola in Ahlat – Bitlis / Turkey was evaluated by the special interest of the
authors within this context. This structure, being one of the unique examples of Turkish –
Islamic monumental cupola (tomb) tradition, is reported to be constructed in 1481 during
Akkoyunlu period, in Ahlat. The cupola is a remarkable example of two layers of cupola
roofing system; an inner dome representing endlessness of the sky in Islamic view and a
covering cone representing Turkish tent tradition from Middle Asia. This approximately six
centuries old structure is unsymmetrical in plan and is stated to have a number of observable
structural problems, like wide cracks and stone deteriorations. Moreover, any structural
treatment is reported within the last four decades. Anyway, cupolas land of Ahlat is located
near Lake Van and this area is denoted as first level of seismicity zone in Turkish Seismic
Zoning Map. This region has experienced strong ground motions in the history and numerous
low magnitude excitations are still occurring as a kind of seismic fatigue loading.
In order to investigate the seismic performance in engineering point of view and to see the
structural deficiencies of Emir Bayındır Cupola, the structure was modeled and analyzed in
3D. First, the architectural dimensions were obtained, data related to current status of the
monument was collected and then structural model of the building was generated in SAP2000
Nonlinear Finite Element Analysis software. Macro modeling approach was taken into
consideration in structural modeling. Response spectrum method was applied for dynamic
analysis. The seismic vulnerability of the cupola by means of high tensile stress
concentrations reaching beyond the capacity was observed by the analysis.
The main objective of the study is to take attentions to cultural heritage in Ahlat region. The
area hosts a number of Seljukian stone work products which can be assumed as formal
documents expressing the existence times of Seljukians on Anatolian peninsula.
This paper provides information about Ahlat cupolas and Seljukian grave stones, the
historical and structural value of the Emir Bayındır Cupola. Structural model and analysis
details for seismic performance evaluation of the cupola will be explained, results will be
discussed in the whole manuscript.
AHLAT CUPOLAS and GRAVE STONES
Ahlat, a city used by Alp Arslan, who opened the doors of Anatolia for the Turks, as a base
before his famous victory in Malazgirt, can be considered an outdoor museum with its unique
cupolas and grave stones. Ahlat is exhibiting its historic heritage of mosques, cupolas, graves,
bridges, baths and aqueducts. The city has numerous structures that have witnessed the
passage of time, such as a Seljuk graveyard, a castle, Hasan Padişah's cupola, Emir Bayındır's
cupola, Sheik Necmettin's cupola, Erzen Hatun's cupola, the İskender Pasha Mosque and
Bayındır Bridge, etc..
Figure 1. Seljukian Grave Stones and Hasan Padişah Cupola
While it is named after Urartian King Lat, Ahlat contains numerous works of art and
architecture from the Seljuk and Ottoman empires. Legend has it that King Lat, ruling the
territory near Lake Van, was badly wounded during an attack against the city by the Med. The
king's daughter cried for her father, mourning and shouting: "Ah! Lat. Oh, dear Lat!” until the
Med conquered the city. When the Urartian king died, this city he loved very much was
named after him. The legend also claims that the Urartian people, the oldest inhabitants of the
city, called it "Halads" while Armenians referred to it as “Shaleat," Syriacs "Kelath," Arabs
"Hil'at" and the Persians and Turks called it "Ahlat."
The city's inhabitants were introduced to Islam during the time of Omar, the second caliph.
Eyad bin Ghanem, who conquered Jazira, also conquered Ahlat, making it part of the Islamic
state. The cupolas located at the entrance of the city, particularly that of Abdurrahman Gazi,
are among the prominent works of architecture that stand out as symbols of the city's Muslim
identity. Abdurrahman Gazi's cupola and the historic mosque near it are located on a green
patch of land covered with roses on a hilltop with a vantage point over Lake Van, hinting at
the richness of civilization in the district.
Cupolas and Grave Stones in Ahlat
Ahlat cupolas resemble Middle Asia Turkish tents by the shape. Thus, cupolas can be
assumed as the convertion of the tent art of Turkish life into architectural products. Therefore,
it is obvious that Turks have introduced cupola architecture into Islamic art. This art was in an
other shape called “Kurgan” in Turkish life, before they met with Islam. Cupola (tomb)
architecture starts in 11th century, within Seljukian period. It is possible to see this kind of
monumental graves on the Turkish migration route from Horasan to Anatolia. Cupolas are
generally constructed for the publicly known and important people like :
•
Rich people who could finance the cupola construction by themselves
•
Some important, successful military commanders
•
Some religiously important people
•
Some important people of public management and their family members
It is reported that Ahlat hosts 19 cupolas in total. 4 of these cupolas were destroyed,
remaining only the graves. Hacı Nene Cupola, Yeşil Cupola and Usta Şagirt Cupolas are the
examples of this damaged ones. Ahlat cupolas belong to Seljukian, İlhanlı, Karakoyunlu and
Akkoyunlu periods.
Figure 2. Erzen Hatun Cupola (left) – Emir Ali Cupola (middle) – Hasan Padişah Cupola (right)
Cupolas in Ahlat, characteristically, have a square base. Some of them were constructed with
four walls following the base and ending up in the same fashion, some of them were
transformed into octagonal form and closed thus in pyramidial shape.
Total of 12 cupolas with cylindircal web exist in Ahlat. Cylindirically webbed cupolas
jumped from square base to dodecagon form, then were transformed into cylindirical form
ending up with a tent type ceiling. Cylindirical cupolas were constructed with two storeys.
Grave was placed in basement, the upper story was arranged for praying.
Other than the cylindirical webbed cupolas, some cupolas which were coverted from square
shape to octagon in elevation. This type cupolas are one storey structures. It is also reported
that, there are 6 cupolas which could not be finished in Ahlat.
One cupola generally covers 3-4 graves. Ornaments on the cupolas are generally special
amblems for a specified family, nation, religious person, etc. Some of the ornaments are
termed as stone jewelleries. Çark-ı Felek ornament is the most commonly observed one
representing the spin of the globe.
Ahlat also hosts special Seljukian grave stones other than the cupolas. Seljukian Graveyard is
located in between İkikubbe neighborhood and Harabaşehir, being the largest graveyard of
Ahlat. Meydanlık Graveyard hosts approximately 1000 gravestones in different shapes and
ornamentings which are dated from early 12th century to 16th century. Besides, 7 graves in
tumulus type, named as “Akıt” by public, exist in Ahlat. This graveyard covering the most
important grave stones are accepted like a kind of formal document that implies the Turkish
existence time in Anatolia. .
Figure 3. Examples of Seljukian Grave Stones in Ahlat
Ahlat type of stone works like cupolas and grave stones are reported to be constructed using
Ahlat stone (ignimbrite). This stone is very soft when it is out of the natural source, then it
gains strength the by time it is faced to athmosphere. Therefore, the special ornaments and
difficult structural shapes of cupolas are thougth to be constructed sudden after the stone was
obtained from its source.
Histrocial value and richment of Ahlat can be further underlined by more cultural heritage
examples. Large-scale projects should be implemented in order to first protect and then
promote Ahlat and the rich civilization of this town to the world.
Authors focused on Emir Bayındır Cupola in Ahlat with a special interest, after area visit.
This two storey cupola is a spectacular example in shape with its openings. Besides, this
massive stone masonry structure is thougth to be vulnerable to seismic excitations due to its
slender structural details and structural deficiencies like cracks, etc. The cupola will be
introduced in detail and then seismic behavior analysis of the cupola will be presented below.
EMİR BAYINDIR CUPOLA
An inscriptive band below the cornice of the cupola announces that the building was built for
Bayindir ibn Rüstem, who died in 1481. It was commissioned by his wife Sah Selime Hatun
and completed in 1491. The architect is unknown, but Baba Can Bey is mentioned as the
builder on an inscriptive plaque found on the small mosque of Emir Bayindir to the north of
the cupola. Cupola belongs to Akkoyunlu Government period. It was restored in 1967 by
General Directorate of Religious Endowments.
Figure 4. Views of Emir Bayındır Cupola
The cupola was built as a part of a complex including a small mosque and zawiya (zaviye),
which is now completely lost now. The spherical cupola (tomb) is raised about 2.50 m above
the ground on a crypt and covered with a dome topped with a shallow conical crown on the
exterior.
The narrow door of the crypt, which is placed off center on the east façade, has sunken below
the ground level and is reached by seven steps. It is about 6.50 m2 on the interior and lit by
narrow slits on the east, west and south walls. A barrel vault aligned east-west supports the
chamber above.
Figure 5. Geometry of Emir Bayındır Cupola
The cylindrical body of the cupola sits on the square crypt whose corners are chamfered on
the exterior to create a dodecagon base for the cupola chamber. The entryway faces the qibla
wall of the mosque and is accessed with a double staircase. The door is framed by three
decorative bands and crowned by an unusual muqarnas vault with floral carvings. Elongated
niches on each side of the door are framed with a band of diamond motifs carved into the
stone. The southern hall of the cylinder facing the lake is opened with ten short columns
defining nine windows. The columns are about 1.00 m high and have heavy muqarnas capitals
are connected with small arches. The parapet below is carved with ornate niches aligned
vertically with the columns. The niche facing the qibla is left shallow to accommodate a
mihrab niche inside the cupola. The inscriptive band, bordered by decorative bands is placed
below the muqarnas cornice. The cupola is made of red (Ahlat) stone.
The cupola is reported not to have been treated within the last forty years. Stone deteriorations
and cracks were observed on the cupola body, by visual inspections of authors. Some stone
spillages on the three of the columns in the size of approximately 20x20x4 cm exist. A
number of serious cracks on arches in between the column muqarnases can be easily
observed. Besides, tension cracks developing from cupola web up to ceiling side seem to be
quiet important.
SEISMIC BEHAVIOR OF EMİR BAYINDIR CUPOLA
Emir Bayındır Cupola is a spectacular example of Turkish cupola tradition. It is reported that,
the architecture Baba Can Bey had constructed this type of cupola only twice; one in
Azerbaijan and the other in Ahlat. Emir Bayındır Cupola is a slender structure with its
columns and openings in the web. It is made of stone masonry. Some serious cracks and
deteriorations exist in the cupola body; probably will be threatening the structure during even
a moderate seismic excitation in the future. Authors desired to investigate the seismic
behavior of Emir Bayındır Cupola within this perspective, especially for the determination of
critical sections to crack under dynamic forces such as earthquakes. It is more convenient to
perform elastic calculations initially for the analyses before protection and restoration of
historic structures. Therefore, using SAP2000 software, the cupola was analyzed under
gravity forces due to the self-weight of the structure and under dynamic loads by linear
response spectrum method.
Material Properties
One of the most challenging cases of the analysis of historical masonry structures is no doubt
estimation of material properties due to a number of uncertainties. Cupola is a stone masonry,
made of Ahlat stone (ignimbrite). Some analysis related to ignimbrite reports
inappropriateness of structural utilization due to its weak mechanical properties and poor
durability abilities. Ignimbrite is basically suggested for decorative works. It has a porous
structure and not suggested for the applications in the regions of strong freezing – thawing
climate cycles. However, cupolas in Ahlat are made of ignimbrite and carry at least the heavy
ceilings consisting of dome and cone.
Regional name of ignimbrite, Ahlat Stone, is commonly used as cover material in various
areas like buildings, mosques, graveyard stones and vaults. The structures constructed with
Ahlat stone and in Selçuklu Era, are still preserving their properties. Ahlat stone has various
colors like brown, dark brown (chestnut), ash. Ahlat stones are some what soft whey they are
extracted from soil, but they harden by the effect of atmosphere. Soft Ahlat stone can be given
into desired shape by hand or by machine. 3-4 storey masonry structure constructed with
Ahlat stone are present in Ahlat district. It has been thought that, Ahlat stone when prevented
from absorbing water can show some degree of heat isolation.
Some properties of the Ahlat stone as stated in the literature are given in the table below.
Moreover, it should be underlined that varying material property values of ignimbrite are
stated in some of the commercial web sites of Ahlat stone suppliers such as compressive
strength (in between 10-45 Mpa), unit weight (in between 19 – 25 kN/m3). Elastic modulus
ignimbrite is reported to be 4500-5000 Mpa in various sources.
Table 1. Properties of Ahlat Stone (Ignimbrite) [9]
Property
Compressive Strength (Mpa)
Flexural Strength (Mpa)
Water Absorption by Volume(%)
Unit Weight (kN/m3)
Specific Gravity (kN/m3)
Porosity (%)
Fullness Ratio (%)
Abrasion (cm3 / 50cm2 )
Value
10.90
1.60
31.05
19.05
26.20
27.29
72.71
27.70
TS 1910 – TS 2513 Limits
50.00
5.00
1.80
2.55
15.00
Analytical Model and Analysis
Emir Bayındır Cupola was modeled in macro modeling approach and analyzed in sap2000,
Advanced Structural Analysis Program. Solid elements (total of 2924 solids) were used for
cupola body. Dome and cone were modeled as shell elements because of some numerical
solution necessities of the software. Mathematical model of the cupola was fined and finalized
for exact analysis step by step as explained below.
The cupola was first modeled considering the basement walls surrounded by ground.
However, first analysis results showed that the results are not seriously affected when the
fixity is started from the ground level. Therefore, the model was first simplified, ignoring the
thick basement walls surrounded by the ground, as shown in Figure 6, and used for further
analysis in order to shorten the analysis time.
In the second step of model fining, Model-2 was first analyzed ignoring all existing structural
deficiencies. Then considering the first analysis results of Model-2 and current situation of the
cupola, different material properties as stated in Table 2 was assigned to simulate the cracked
and damaged locations. All analysis was finally reperformed on the final version of Model-2.
Table 2. Assigned Modulus of Elasticity Values for Model-2 final
Structural Member
Cupola web and Dome
Cone and Damaged Columns
Cracked Arch Locations
Situation
relatively fine
having local deteriorations
having observable cracks
Modulus of Elasticity (Mpa)
4500
4000
2500
a
b
c
d
Figure 6. Model -1 (a-b) and Model – 2 (c-d) for Emir Bayındır Cupola
Dead load analysis, modal analysis and linear response spectrum analysis were performed for
the cupola on Model-2 final version. Linear-elastic analysis was performed so as to specify
critical parts that could exist due to various load effects and to determine overall stability of
the structure. Since the structure is stone masonry, stresses and especially tensile stress
concentrations obtained by the analysis was considered and evaluated basically.
Analysis Results
Results of Modal Analysis
Modal analysis was performed in order to define the period of the structure that will be used
in response spectrum analysis. Moreover, considering the period values together with the
stresses under dead loads; Model-2 was fined. Model–2, was modified and decided to be used
in further analysis as Model-2 final. The results of the modal analysis are stated in the Table 3
below.
Table 3. Modal Analysis Results
Mod Number
1
2
3
4
5
6
Period (sec)
Model-2
Model-2 final
0.192
0.205
0.174
0.185
0.106
0.113
0.075
0.080
0.064
0.068
0.047
0.051
Mod Number
7
8
9
10
11
12
Period (sec)
Model-2
Model-2 final
0.045
0.049
0.038
0.040
0.031
0.034
0.031
0.033
0.028
0.030
0.025
0.027
Results of Dead Load Analysis
Cupola was analyzed under dead loads (weights of dome and cone). Tensile stress
concentrations around the door opening, over the arches in between the column muqarnases
and in bracelet zone under ceiling were clearly observed; which mostly coincides with
existing wounded situation of the cupola. Since, the tensile stresses around these locations
basically vary around 0.60 Mpa being less than the capacity (The flexural capacity of
ignimbrite is reported to be 1.60 Mpa (kaynak).The split cylinder strength usually ranges
from 50 to 75% of the modulus of rapture. (kaynak) So, the tensile strength of the ignimbrite
could vary 0.80-1.20 Mpa.), it is thought that these cracks could have occurred due to material
loss of stones decreasing the capacity by durability effects in time or some kind of seismic
actions providing more sudden tensile stresses. Further, tensile stresses around 2.50 Mpa of
some few members were also obtained under the structure weigth itself.
Compressive stresses under dead loads reaching even the capacity (referred to Table xx) were
observed in very few elements under the basement of first storey (praying area).Compressive
stresses was obtained to reach up to 34% of compression strength (referred to Table xx) of the
stone material in some of the column webs and especially transition zones from muqarnas to
column body.
Figure xx. Contours under Dead Load
Results of Response Spectrum Analysis
Cupola was analyzed under dynamic forces by response spectrum method in both global
directions.(TEC) Maximum tensile stresses were obtained around the column bases and
arches in between the muqarnases, reaching up to 1.50 Mpa, which is beyond the capacity
(kaynak). This analysis result can be somehow support the idea that; cracks especially over
the arches could have occured due to some past seismic excitations.
Figure xx. Stress Contours by Linear Response Spectrum Analysis
Considering the dynamic analysis results and seismicity of the region, one can end up with
underlining the high vulnerabilty of the cupola for dynamic forces. This implies the necessity
of seismic protection of the cupola by a proper technique such as structural tendon systems.( )
CONCLUDING REMARKS
Emir Bayındır Cupola in Ahlat was analytically investigated on engineering perspective;
after visual inspections in-situ. However, the basic objective of the study was to take
attentions to Ahlat and its rich cultural heritage on ordinary world citizens’ perspective.
Seljukian style Ahlat cupolas and grave stones are some kind of formal historical documents
of first Turkish attendance to Anatolia dating back to 11th century. Visual inspections of
authors in Ahlat desire to underline the necessity of interdisciplinary partnership for cultural
heritage protection in the area. So that; historical masonry of the area was basically made of
ignimbrite which is reported to be unsuitable for structural purposes as well as poor durability
properties.
By in situ evaluations of historical stone works in Ahlat, Emir Bayındır Cupola seemed to be
the most vulnerable one among the others with its special architecture and existing situation.
So, this structure was chosen to be analyzed by the special interest of authors. Before
structural treatment and restorations, structural analysis of the historical masonry is necessary.
Some basic remarks of the study can be stated as below.
Linear-elastic analysis could be performed initially so as to specify critical parts that
could exist due to various load effects and to determine overall stability of the structure.
REFERENCES
1. Çelebi, C., Yaşayan Kültür Ahlat, Kültür Bakanlığı Yayınları: 2711, Kültür Bakanlığı
HAGEM, Ankara, (2001).
2.Demirtaşlı, E., Pisoni, C., .....,Ahlat-Adilcevaz Bölgesinin Jeolisi (Van Gölü Kuzeyi),
Maden Tetkik ve Arama Enstitüsü Yayınları, Ankara. (in Turkish)
3.Erken, S., 1977, Türkiyede Vakif Abideler ve Eski Eserler. Ankara: Vakiflar Genel
Müdürlügü Yayinlari, II, pp.262-267. (in Turkish)
4.Park, R., Paulay, T., 1975, Reinforced Concrete Structures, John Wiley and Sons
Publication, U.S.A.
5.Psycharis, I., N., “A Probe into the Seismic History of Athens, Greece from the Current
State of a Classical Monument”, 2007, Earthquake Spectra Volume 23, Issue 2, pp. 393415.
6.SAP2000 V11.0.0, Structural Analysis Program.
7.“Seismic Qualification of Passive Mitigation Devices”, 2005, Edited by Dorka, U., Garcia,
J., CASCADE, Report No-1.
8.Sözen, M., 1981, Anadolu'da Akkoyunlu Mimarisi. Istanbul: Turkiye Turing ve Otomobil
Kurumu, pp.155-157. (in Turkish)
9.Şimşek, O., Erdal, M., 2004, Investigation of Some Mechanical and Physical Properties of
the Ahlat Stone (Ignimbrite), Gazi University Journal of Science, Vol. 17(4), pp. 71-78.
10. Toker, S., Ünay, A., İ., 2004, Mathematical Modelling and Finite Element Analysis of
Masonry Arch Bridges, Gazi .Univerity . Journal of Science, Vol. 17(2, pp. 129-139.
11. TS 1910, 1977, Kaplama Olarak Kullanılan Doğal Taşlar, Türk Standardları Enstitüsü,
Ankara (1977).
12. TS 2513, Doğal Yapı Taşları, Türk Standardları Enstitüsü, Ankara, (1977).
13. Deprem Bölgelerinde Yapılacak Yapılar Hakkında Yönetmelik, 2007, (in Turkish)
14. Uluçam, A., 2002, Ortaçag Sonrasinda Van Gölü ve Çevresi Mimarligi II: Bitlis. Ankara:
Türkiye Cumhuriyeti Kültür Bakanligi Yayinlari, pp. 202-205. (in Turkish)
15. www.deprem.gov.tr (Official Website of General Directorate of Disaster Affairs
Earthquake Research Department of Turkey).
16. www.ahlattasi.com.tr (source for some pictures)
17. www.ahlat.bel.tr (Official Web Site for Ahlat Municipality)