İstanbul Bizans mimarisinde kullanılan tuğlanın fiziksel ve mekanik özellikleri
Characteristics of brick used in Byzantine architecture in İstanbul
Yazar: YEGAN KAHYA
Danışman: PROF. DR. METİN AHUNBAY
İstanbul Teknik Üniversitesi / Fen Bilimleri Enstitüsü
Derece: Doktora, 1992
Konu: Mimarlık = Architecture
Dizin: Bizans mimarisi = Byzantine architecture ; Restorasyon = Restoration ; Tuğla = Brick ; Yapı malzemeleri = Building materials ; İstanbul = Istanbul

Özet:
Mimarlık Tarihi ile Yapı Malzemesi konularının arakesitinde yapılan bu çalışma, İstanbul'daki Bizans yapılarında kullanılan tuğlanın özelliklerini laboratuvar deneylerine dayalı olarak inceleyerek, bu konuda bir ölçüde ilgi eksikliğinden doğan boşluğu doldurmayı amaçlamaktadır. Alan araştırması, laboratuvar analizleri, kitaplık-arşiv araştırmaları ve değerlendirme aşamalarından oluşan bu tez çalışmasında konular altı ana başlıkta sunulmuştur. Tezin girişini oluşturan 1. Bölüm 'de, çalışmanın amacı, kapsamı ve uygulanan araştırma yöntemi ayrıntılı olarak açıklanmış, bu konuda daha önce yapılmış olan çalışmalar özetlenmiştir. Geleneksel üretimde tuğla malzemenin özelliklerini daha çok hammaddenin niteliği ile tuğlacının bilgi ve deneyimi belirlemektedir. Tecrübe yoluyla ustadan çırağa aktarılan bilgiler geniş bir zaman dilimi içinde çok yavaş gelişmiştir. İlkel yöntemlere dayalı bu üretim süreci Bölüm 2.1 'de ayrıntılı olarak ele alınmıştır. Bu üretimin Bizans dönemindeki organizasyonu Bölüm 2. 2' de tartışılmış, üretim yapılan yerlere ilişkin olarak elde edilen bazı ipuçları ise Bölüm 2. 3 'de değerlendirilmiştir. 3. Bölüm, iki başlıkta incelenmiş tir. Birinci alt bölümde tuğla malzemenin Bizans yapılarında kullanıldığı yerler ve kullanılış biçimine değinilmiş, ikincisinde ise Bizans tuğlasının biçimsel ve boyutsal özellikleri, Roma ve Osmanlı tuğlası ile karşılaştırmalı bir perspektifte incelenmiştir. Yine bu bölümde, İstanbul'da sık olarak kullanılan tuğla boyutları ve bu boyutların Bizans ölçü birimleriyle ilişkileri araştırılmıştır. Bu boyutların kronolojik olarak incelenmesiyle de bazı sonuçlara ulaşılmıştır. Laboratuvar çalışmalarında kullanılmak üzere tuğla örnek alınmasına izin verilen yapılar 4. Bölüm' de kronolojik bir düzende sunulmuştur. Çalışmanın 5.Bölümü'nü, bu yapılardan alman tuğla örnekler üzerinde yapılan laboratuvar çalışmaları oluşturmaktadır. Saptanan deney programı çerçevesinde 'karot' tuğla numuneleri üzerinde fiziksel ve mekanik özelliklerin belirlenmesine yönelik deneyler yapılmıştır. Bizans tuğla üretiminin düzeyini tartışabilmek için aynı deneyler, Erken Osmanlı tuğlası, çağdaş harman tuğla ve fabrikasyon tuğla üzerinde de yinelenmiştir. Laboratuvar çalışmalarından elde edilen sonuçlar Bölüm 5.4'de değerlendirilmiştir. Bulgular, Bizans tuğlasının fiziksel ve özellikle de mekanik özellikleri açısından oldukça iyi nitelikler taşıdığını göstermektedir. Günümüzden yüzyıllarca önce üretilen bu tuğlalar, aynı üretim yönteminin uygulandığı bu günkü harman tuğlalarından çok, tamamen endüstriyel yöntemlerle elde edilen çağdaş fabrika tuğlalarına daha yakın özellikler taşımaktadırlar. Genel sonuçları içeren 6-Bölüm'de, bölümlerden derlenen veriler toplu olarak değerlendirilmiş, Bizans tuğla teknolojisinin geleneksel yöntemlerle ulaştığı düzey nedenleriyle tartışılarak Bizans ustalarının üretimin her aşamasını denetleyebildikleri bir bilgi birikimi ve deneyime sahip oldukları sonucuna ulaşılmıştır. Çalışmanın sonunda dört ek bulunmaktadır. Ek A 'da İstanbul ve Trakya'daki tuğla üretim merkezlerini gösteren haritalar yeralmaktadır. Ek B'de, incelenen yapılarda ölçülen tuğla boyutlarının dökümü verilmiştir. Konulara ilişkin fotoğraflar, metin içinde bahsedildikleri sıraya göre Ek C'de sunulmuştur. Ek D ise yapılan deneylerin ay rıntılı sonuçlarını içeren tablolar şeklinde düzenlenmiştir.

Abstract:
Brick has been used in buildings since ancient times. Its widespread adoption was due to such factors as its raw material being readily available, its durability and the possibility that it could be produced in almost infinite variety of forms in a short time- mate also surv hist arti its negl cond take whic rese Ap rial f av ivin oria stic phys ecte ucti n f r h co arch prec, Ro oure g ex ns h f ea ical d. T ng 1 om B nsis and iati mans d by ampl ave ture pro his abor yzan ts o dat ng mad the es dev s of pert diss ator tine f fi a as the e use Byza of t oted brie ies a ertat y re buil eld w sessm valu of ntin heir the k us s a ion sear ding ork, ent e an it in es a arc ir a age i buil aims eh o s in lab is pr d ve grea s is hitec ttent n Byz ding at fi n cy 1st orato esent rsat t qu re ture ion anti mat İlin lind anbu ry ed i ility antiti f lecte Arc rathe ne arc erial g thi rical 1. Th tests, n six of es. I d by hitec r to hitec has s ga spec is s arc chapt the t was the tural the ture ; been P by imens tudy, hival ers. The first chapter of the dissertation is devoted to the introduction to the subject, namely the purpose and the methodology of the research. methods traditi one s i d on the transf e slow an not mu Byzanti methods can say today a Byzanti raw mat hapte of p onal e and other r of d Ion eh i ne bu did that re qu ne er erial r 2 rodu prod the sid expe g pr nfor ilde not con ite a. B -cl introd ction uction knowl e, det rience ocess mation rs. Co change ventio simila rick p ay- is uces t and the, the q edge an ermined from s in hist about nsideri much i nal bri r to th roducti quarri he pro uali d ex the enio ory. th ng t n th ck p e pr on h ed a data duct ty o peri qua rs t Unf e p he e co rodu oduc as f nd c on ion f th ence lity o a ortu rodu fact urse ctio tion our lean th at b e ra of of ppre nate ctio th of n me sy phas ed o e tra rickya w mate the br the br ntices iy, t n met at pr centur thods stem es. Fi f imp diti rds. rial ickm ick. wa here hods oduc ies, ado used rst urit onal In on aker The s a is of tion one pted in the ies. vmThen it is mixed with water to have the right consistency. The dough is then shaped by using molds. When the bricks are dry, they are ready for firing in the kiln. In section 2.1. the production process using traditional technology is studied in detail. Brick production in Byzantine period, with special reference to the organization of production, brick makers guild and the rules for professional inspec tion are discussed in section 2.2. plac asse cone the prod fact Otto Horn Harm cont was Müre Kira trad the Du es o ssme erni loc uced tha man, s anla inue near fte, z (K itio regi e to f br nt ng b alit. Fu t th peri ited r a d al Tek Kal iraz nal on. the ick p of rick ies rther ere od. 0 at nd K ong t irdağ amış, lı). brick sea roduc Ottom and t where rese were ne of vill araağ hese, at Erek Kilns prod rcity tion, an ile p the arch two thes ages aç. coast such li (E at t uctio of some docum roduc se on ki main e was like Tradi s unt loca rikli hese n, me publis assump ents. tion fo buildin In rem produ the co Haskö tional il 1970 lities ce), G sites a eting t hed tion Ott r Is 9 ains ctio asts y, br 's. as anos re s he m inf s we oman tanb mate co n s of Piri ick The Hor (G till oder ormation re made docum ul disc rials nf irmed ites du the Go paşa, E produc other ce e (Hoşk aziköy ) active n needs on by ents lose were the ring İden yüp, tion ntre öy), and in of It is significant that brick kilns were usually established near clay ore beds. Thus Ottoman historic data and our observations at the same sites may be taken as evidence that the same areas served for brick production during the Byzantine period. This assumption is backed up by the fact that the village of Piripaşa on the Golden Horn was known as the "Keremitya" in Byzantine period. The fact that for the reconstruction of the Valens Aqueduct (765/6) brickmakers were summoned from Thrace confirms this assump tion. comb Byza begi buil reac shap its adva prop Otto dime the syst cons Th inat ntin nnin ding hed ed o usa need erti man nsio resu ems. ider e dimen ion wit e build g of B mater its max rnament ge dur level es of B bricks ns of c Its we The ation. sion h ot ings yzan ial imum al t ing of p yzan. B ommo re rat Acco al p her m are tine for duri iles. Late roduc tine y me nly u relat io rding roper ateri discu peri wall ng Pa The Byz tion. brick ans sed b ed t of to t ties als ssed od, s a leol spec anti In are of rick o t shri he d of and t in C brie nd r ogan ial b ne p thi comp field s mer he B nkage ata, bri he w hapt k b oof i peri rick erio s c ared su e de yzan w assu ck, ay i er ecam ng. od w pr d m hapt wit rvey term tine as mpti its t was 3. Wi e the Brick ith sp pducti anif es er, p h Rom, fir ined a meas taken ons we use in used in th the major usage ecially on and ts the hysical an and st the nd then urement into re made IXon the size of Byzantine brick molds. It was possible to reach some conclusions about changes in brick sizes by chronological examination of the thickness and length of bricks used in Byzantine buildings in Istanbul. In general, a considerable decrease in brick lengths was observed in time. This result was reached by comparing the lengths of bricks from different buildings. It was also possible to distinguish different construction periods by the sizes of bricks in some buildings. As regards the thickness of bricks, no considerable change was observed during the Byzantine era. Due to the haphazard nature of the variations in brick thicknesses, it was not possible to come to definite conclusions. brie list the Due to monu Mona Chur coul cons take prop and In k sa ed c Earl to t take ment ster eh o d no true n ha erti anal the mples hrono y Ott he fa bri s fro y, t f Lip t be tion ve be es ha ysis fourth were t logical oman pe ct that ck spe m Paleo he Chu s Fionas include dates o en dete ve also of the chap aken iy. riod som cime loğa reh tery d in f wa rmin bee buil ter, for Brie bui e in ns n Pe of, Ki thi lis, ed ; n sp ding the lab k sam lding stitu by d riod Pamm lise s stu from brie ecif i s ine buil orat pies s fo tion rill like akar Cami dy. whi k c ed t lude ding ory wer r a s r ing, the isto si, In t ch ours hrou d in s f r exp e al comp ef us ma Ch s M Ese his the ing gh d the om erim so t arat ed ny urch onas Kap cha sam and etai sur whic ents aken ive perm imp of tery i M pter pies ma led vey. h the, are from study. ission ortant Chora., the escidi, the were terial survey The most significant part of the dissertation, Chapter 5, contains laboratory experiments on bricks which were produced hundred of years ago and are still in good condition. Experiments, on apparent density, water absorp tion (by weight and volume), porosity, hardness (Mohs), ultrasound and compression were carried on cylindrical specimens with a diameter of 2.5 cm and a height of 5.0 cm. Real density was tested on the powdered specimen taken from the same brick. Schmidt hardness was tested on the building. In order to test the mineralogical structures of bricks, thin sections of specimens were prepared. The results of the experiments were evaluated under three main headings in Section 5.4. The first sub-section is about the physical and mechanical properties of Byzantine brick. The change of these properties in time has been reviewed also. The second and third sub-sections were devoted to comparative analysis. In order to have a better estimation of Byzantine brick production, the results of tests on Byzantine specimens were compared with results obtained from Early Ottoman and contemporary bricks whichwere geogr Byzan produ and B prope moder physi brick conte stren Byzan concr tower St.Po Saray the 0 metho the r conse 11th- Byzan prod aphi tine ced yzan rtie n T cal s ha mpor ghts tine ete s Bl lyeu the ttom d, t esul cuti 12th tine uced w cal ar bricks bricks ; tine br s of By urkish and esp ve high ary br which bricks and in 5 and 5 ktos, t y even an brie hey cou ts of t ve per C. and era wh ith ea. iter com ick zant sta ecia er v icks vari app some 6 f he c surp ks w Id n ests iods th ich sim Obs e fa pari was ine ndar lly alue. E ed b roac exa rom hurc asse ere ot r, it na e L span ilar t erving r too s son bet made in bricks ds. Th mechani s than special etween hed the mples 1 the L h of t d this also pr each was mely ate th P 4 By s almos echn tha uper ween the are e r cal TS 7 iy 17 N qua ike and he valu oduc e sa ossi th-6 zant t a olog t t ior in thi also esul prop 04 s with /mm2 lity the Wal Pant e co ed me q ble th ine thou y wi he to th dustr rd su chec ts i ertie ugges the and of Ciste Is, ocrat nside by u ualit to C, peri sand thin prope e tra ially b-sec ked a ndica s of ted v ir c 35 N toda rn Ae the or a rably sing y. Ac demar 8th- od w years the rtie diti pr tion gain ted Byz alue ompr /mm2 y ' s tios chur nd. Al the cord cate 10th ithi same s of onally oduced. The st the that antine s for essive, the B.225, the ch of Tekfur though same ing to four C, n the Chapter six, which includes the conclusions of the research on Byzantine bricks in Istanbul contains discussions on the level of technology of Byzantine bricks under the light of findings of Chapter five and the remaining sections. product archite technol by the evident experie product the mol methods bricks, contemp propert 11 resu ion, p cture. ogy rea careful that B nee by ion pro ding, of thi posse orary i ies of Its aral The ched and yzan whic cedu dryi s pe ss ndus toda conf i lei high by t effi tine h the re f r ng a riod mecha trial y's t rm tha to it leve raditi cient f orema y wer om the nd fi were s nical ly pro raditi t there s dens 1 that onal me product ns had e able prepar ring s o deve proper duced b onally is e u th thod ion gr to atio tage lope ties rick prod a dev sage e Byz s can at tha eat k cont n of t s. Th d tha simi s ', ra uced b elop in anti be t ti nowl rol he c e p t, lar ther rick ed Byza ne expl me. edge all lay rodu Byza to tha s. brick ntine brick ained It is and the up to ction ntine the n the Although the chronological order established by this research on Byzantine bricks seems quite meaningful, we think that it should be considered with caution due to the limited number of cases included in the survey. Nevertheless, the results may initiate further research on the subject and if the results of future studies on the subject with increased number of specimens from more buildings confirm our finds, it will be possible to use this method for dating Byzantine buildings along with the xiassessment of other data like the quality of the brick, historical sources and construction details. When the method is justified, it will probably contribute to determination of approximate construction dates for buildings of unknown dates, even if it will fall within wide intervals like centuries. At the end of the study, there is an appendix which consists of four sections. The first (Ek A) includes maps showing the brick production sites in Istanbul and in Thrace. The list of brick measurements taken from the surveyed buildings is given in (Ek material is presented in (Ek C), appearance in the text. (Ek D) comprising the details of the conducted on the specimens. B). Related photographic in the order of its contains the tables results of the tests Xll