UNIVERSITÀ DEGLI STUDI DI PADOVA Dipartimento di Ingegneria Civile Edile e Ambientale Laurea Magistrale a Ciclo Unico in Ingegneria Edile – Architettura SEISMIC VULNERABILITY ASSESSMENT OF CLUSTERED BUILDINGS IN THE HISTORICAL CENTER OF TIMISOARA: FRAGILITY CURVES FOR OUT-OF-PLANE LOCAL MECHANISMS OF COLLAPSE RELATORE: Ch.ma Prof.ssa DA PORTO FRANCESCA CORRELATORI: Ch.mo Prof. CLAUDIO MODENA Ing. MARSON CLAUDIA Ing. MUNARI MARCO Ing. TAFFAREL SABRINA LAUREANDA: MARGHERITA ROVERATO ANNO ACCADEMICO 2014 / 2015 ACKNOWLEDGEMENTS I wish to express my sincere thanks to Prof. Francesca da Porto, supervisor of this thesis, and to Prof. Carlo Modena for the disposability shown and for the help provided in this thesis. My sincere thank you to Ing. Marco Munari, Ing. Claudia Marson and Ing. Sabrina Taffarel for the valuable guidance and the continuous encouragement as well as for the infinite patience. I am also grateful to the Polytechnic University of Timisoara for the help and the hospitality during the on-site activities and in particular I would like to thank Ing. Marius Mosoarca and Arch. Bogdan Demetrescu for the great disposability and the indispensable material provided. Thank you to my colleague and friend Claudia, with whom I spend the most part of my time and energy in the last months, to make enjoyable even the most difficult moments of this thesis. My heartfelt thanks to Elena, Giorgia and Linda, which join me and enjoy with me every day, and I mean literally every day, of these five years of University. My most beautiful academic memories are bond to you. I wish to express my deepest gratitude to my Family which has encouraged me and support me every day of my life, as well as tolerated me on my study periods. I am also grateful to Michele, to support and endure me and to be my anchor of peacefulness. SUMMARY The evaluation of the seismic vulnerability of historical buildings is important in order to develop prevention strategies and to protect the existing cultural heritage. The vulnerability analysis gives a preliminary assessment of the possible damages that a building or an aggregate can develop during a seismic event. The adopted methodology provides an immediate tool to evaluate the seismic vulnerability of an entire city centre, starting from easily detectable geometrical features. In this thesis the vulnerability analysis of the historical city center of Timisoara is discussed. The city is situated in the Banat region in western part of Romania, which is considered as the second most important seismic zone of Romania, being subjected to shallow earthquakes of crustal type. The buildings of the historical centre are organized in rectangular blocks composed by clustered buildings. 36 blocks of the city center and 4 blocks of the district of Iosefin are analyzed, for a total of 245 analyzed structural units. The proposed methodology begins with a preliminary knowledge phase, in which an urban and historical research is performed. This analysis aims to define architectural and urban characteristics, urban evolution and recurrent constructive techniques, which are indeed essential to address the analysis and to choose the aspects to investigate. The second phase consisted in the on-site activity, in which important data about the building geometry, organization and structure are collected. The data are organized filling forms which are suitable for the rapid survey of masonry buildings. The collected data are analyzed in order to identify the most common geometrical and structural characteristics. The study continues with the typological analysis of the on-site data: for each building the most important characteristics have been analyzed and 8 macro- typologies have been defined. Each macro-typology has been subdivided in typologies according to the stories number and so defining a total of 33 typologies. Likewise each typology is divided in micro-typologies, in accordance with the wall thickness of the ground floor. Thanks to a map of the ground floor internal organization of the city center buildings, dated back approximately to the 1980, the analysis of the plan modules is possible. The combination of the on-site data and the plan modules analysis allow a complete knowledge of the main building characteristics that are relevant for the seismic behavior. A seismic vulnerability assessment is performed with the software Vulnus, which evaluates the vulnerability of out of plane and in plane local mechanisms of collapse. The software is used in two different applications: the first one regards the study of three blocks of the historical center, with the purpose of defining the vulnerability level of the three aggregate building; the second application regards the study of four singular structural units, to compare the results obtained for two different level of information, which are the real case, obtained by detailed plans and sections, and the survey case, obtained using the city plan of 1980 and information collected on-site. The final aim of this thesis is to define, for each typology, the vulnerability assessment for the out of plane mechanisms of simple overturning and vertical bending and consequently to provide a global vulnerability assessment of the entire historical center, with the possibility to extend the results to similar buildings and urban centers. Therefore the methodology goes through the analysis and the verification of these local mechanisms, up to define the capacity curve of each typology. The analysis is made considering a set of varying parameters which takes into account the uncertainty of information caused by a rapid and external survey. The validity of the entire process is checked comparing the results of four singular structural units, analyzed using three different levels of information: the real case, the rapid survey case and the typological case. Finally for each typology the fragility curves are defined, reporting the probability of exceeding defined levels of damage for specific peak ground accelerations. The typological analysis defines a preliminary vulnerability assessment starting from a rapid survey on large scale. The results can be extended to constructions with the same structural and geometrical characteristics of the analyzed ones, widen the assessment to an urban scale. INDEX 1 TIMISOARA ....................................................................................................... 5 1.1 GEOGRAPHICAL LOCATION .............................................................. 5 1.2 GEOMORPHOLOGY ............................................................................. 8 1.2.1 Morphology .............................................................................................. 12 1.2.2 Geological framework .............................................................................. 12 1.2.4 Geotechnical setting ................................................................................. 16 1.3 SEISMICITY .......................................................................................... 19 1.3.1 In Romania ............................................................................................... 20 1.3.2 In Banat region ........................................................................................ 21 1.4 HISTORICAL EARTHQUAKES ........................................................... 27 1.4.1 In Romania ............................................................................................... 27 1.4.2 In Banat .................................................................................................... 30 1.5 HISTORY OF TIMIŞOARA .................................................................. 34 1.5.1 Etymology ................................................................................................ 34 1.5.2 Antiquity .................................................................................................. 34 1.5.3 Dacian and Roman period ....................................................................... 35 1.5.4 Committee of Timiş ................................................................................. 36 1.5.5 Ottoman domination ................................................................................ 37 1.5.6 Habsburg rule ........................................................................................... 39 1.5.7 Revolution of 1848-1849 ......................................................................... 40 1.5.8 Voivodeship of Serbia and Banat of Temeschwar ................................... 41 1.5.9 The Kingdom of Hungary from 1860 to 1918 ......................................... 42 1.5.10 World War the First (1914-1920) ............................................................ 43 1.5.11 Interwar Period (1919 -1947) ................................................................... 44 1.5.12 Second World War ................................................................................... 45 1.5.13 Timisoara under socialist ........................................................................ 46 1.5.14 Student revolt of 1956 .............................................................................. 47 1.5.15 1989 Revolution ....................................................................................... 47 1.5.16 Romania today ......................................................................................... 49 1.6 URBAN EVOLUTION ........................................................................... 50 1.6.1 From XII